Preparation of low-viscosity polymers

Abstract

The present invention relates to a method for preparing a polymer composition, said method comprising the steps of: a) preparing a reaction mixture comprising as component A) an ethylenically unsaturated monomer or a mixture of ethylenically unsaturated monomers and as component B) a 1-alkene or a mixture of 1-alkenes; b) adding a Co(II) complex as a catalytic chain transfer agent to the reaction mixture; c) adding a radical initiator; and d) reacting the reaction mixture to obtain the polymer composition, wherein the total amount of the radical initiator added to the reaction mixture is at least 0.05% by weight relative to the total weight of components A) and B). The present invention also relates to the use of a Co(II) complex as catalytic chain transfer agent for the polymerization of a reaction mixture comprising an ethylenically unsaturated monomer or a mixture of ethylenically unsaturated monomers, a radical initiator, and a 1-alkene or a mixture of 1-alkenes, wherein the total amount of the radical initiator added to the reaction mixture is at least 0.05% by weight relative to the total weight of the ethylenically unsaturated monomer or mixture of ethylenically unsaturated monomers and the 1-alkene or mixture of 1-alkenes.

Claims

1. A method for preparing a polymer composition, said method comprising: preparing a reaction mixture comprising a component A) and a component B), wherein component A) is an ethylenically unsaturated monomer having a formula (I) or a mixture of ethylenically unsaturated monomers each having a formula (I): ##STR00007## wherein R.sup.1 and R.sup.2 each independently represent a hydrogen atom or a group of the formula COORS.sup.5, R.sup.3 represents a hydrogen atom or a methyl group, R.sup.4 represents a C.sub.1 to C.sub.30 alkyl group, a C.sub.2 to C.sub.30 alkenyl group, a C.sub.2 to C.sub.30 alkynyl group or a C.sub.3 to C.sub.30 cycloalkyl group, and R.sup.5 represents a hydrogen atom or a C.sub.1 to C.sub.30 alkyl group, a C.sub.2 to C.sub.30 alkenyl group, or a C.sub.2 to C.sub.30 alkynyl group, and component B) is a 1-alkene or a mixture of 1-alkenes selected from the group consisting of 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene, 1-eicosene, 1-heneicosene, 1-docosene, 1-tricosene, 1-tetracosene, 1-pentacosene, 1-hexacosene, 1-heptacosene, 1-octacosene, 1-nonacosene, 1-triacontene, 1-hentriacontene, and 1-dotriaconene; adding a Co(II) complex as a catalytic chain transfer agent to the reaction mixture; adding a radical initiator; and reacting the reaction mixture to obtain a polymer composition having a kinematic viscosity of less than 25 mm.sup.2/s measured at 100 C. according to ASTM D 445, wherein a total amount of the radical initiator added to the reaction mixture is at least 0.05% by weight relative to a total weight of components A) and B).

2. The method according to claim 1, wherein the reaction mixture comprises at least 50% by weight of component A) relative to the total weight of components A) and B).

3. The method according to claim 1, wherein the reaction mixture comprises at least 10% by weight of component B) relative to the total weight of components A) and B).

4. The method according to claim 1, wherein the Co(II) complex comprises Co(II) and at least one of the ligands according to formulae (VI) to (XI) ##STR00008## wherein each R.sup.22 independently represents a phenyl group or a C.sub.1 to C.sub.12 alkyl group, or two R.sup.22 on adjacent carbon atoms together represent a C.sub.5 to C.sub.8 alkylene group; each R.sup.23 independently represents a hydrogen atom or a C.sub.1 to C.sub.12 alkyl group; each R.sup.24 independently represents a hydroxyl group or an amino group; each R.sup.25 independently represents a hydrogen atom, a C.sub.1 to C.sub.12 alkyl group, a phenyl group, a hydroxyphenyl group, or a C.sub.1 to C.sub.4 alkoxyphenyl group; and each n represents an integer 2 or 3.

5. The method according to claim 1, wherein the amount of Co(II) added to the reaction mixture is from 30 to 500 ppm by weight relative to the total weight of components A) and B).

6. The method according to claim 1, wherein a total amount of radical initiator added to the reaction mixture is from 0.1 to 3.5% by weight relative to the total weight of components A) and B).

7. The method according to claim 1, wherein component B) comprises 1-decene.

8. The method according to claim 1, wherein component A) comprises a mixture of C.sub.12- and C.sub.14-methacrylates.

9. The method according to claim 8, wherein component B) comprises 1-decene.

10. The method according to claim 1, wherein component A) comprises a mixture of C.sub.10-, C.sub.12-, C.sub.13-, C.sub.14- and C.sub.15-methacrylates.

11. The method according to claim 10, wherein component B) comprises 1-decene.

12. The method according to claim 11, wherein the Co(II) complex comprises 5,10,15,20-tetraphenyl porphine cobalt(II).

13. The method according to claim 1, wherein the Co(II) complex comprises 5,10,15,20-tetraphenyl porphine cobalt(II).

14. A process, comprising polymerizing a reaction mixture with a Co(II) complex as catalytic chain transfer agent, to obtain a polymer composition having a kinematic viscosity of less than 25 mm.sup.2/s measured at 100 C. according to ASTM D 445, wherein the reaction mixture comprises an ethylenically unsaturated monomer or a mixture of ethylenically unsaturated monomers, a radical initiator, and a 1-alkene or a mixture of 1-alkenes selected from the group consisting of 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene, 1-eicosene, 1-heneicosene, 1-docosene, 1-tricosene, 1-tetracosene, 1-pentacosene, 1 -hexacosene, 1 -heptacosene, 1 -octacosene, 1 -nonacosene, 1 -triacontene, 1 -hentriacontene, and 1-dotriaconene, wherein a total amount of the radical initiator added to the reaction mixture is at least 0.05% by weight relative to a total weight of the ethylenically unsaturated monomer or mixture of ethylenically unsaturated monomers and the 1 -alkene or mixture of 1-alkenes, and wherein the ethylenically unsaturated monomer has a formula (I) or the mixture of ethylenically unsaturated monomers has a formula (I): ##STR00009## wherein R.sup.l and R.sup.2 each independently represent a hydrogen atom or a group of the formula COOR.sup.5, R.sup.3 represents a hydrogen atom or a methyl group, R.sup.4 represents a C.sub.1 to C.sub.30 alkyl group, a C.sub.2 to C.sub.30 alkenyl group, a C.sub.2 to C.sub.30 alkynyl group or a C.sub.3 to C.sub.30 cycloalkyl group, and R.sup.5 represents a hydrogen atom or a C.sub.1 to C.sub.30 alkyl group, a C.sub.2 to C.sub.30 alkenyl group, or a C.sub.2 to C.sub.30 alkynyl group.

Description

EXAMPLES

(1) In the following examples, Isodecyl-methacrylate (IDMA) is a mixture consisting of 98.7% by weight C.sub.10 methacrylate, 0.8% by weight C.sub.12 methacrylate, and 0.5% by weight C.sub.14 methacrylate. The degree of linearity of IDMA is approximately 0%.

(2) Methacrylate from LIAL 125 alcohol (LIMA) is a mixture consisting of 24.3% by weight C.sub.12 methacrylate, 29.4% by weight C.sub.13 methacrylate, 28.4% by weight C.sub.14 methacrylate, and 17.9% by weight C.sub.15 methacrylate. The degree of linearity of LIMA is approximately 40%.

(3) Lauryl methacrylate (LMA) is a mixture consisting of 72.2% by weight C.sub.12 methacrylate, and 27.8% by weight C.sub.14 methacrylate. The degree of linearity of LIAL is approximately 100%.

Example 1

Comparative Example

(4) Example 1 is equal to Example 1 as disclosed in U.S. Pat. No. 5,691,284 and was prepared as follows:

(5) 141 g of 1-decene was heated to 160 C. in a reaction vessel. A mixture of 113 g of IDMA and 135 g of LIMA was fed in over 4 hours. At the end of the feed, the batch was polymerized for another 12 hours. During the entire reaction time of 16 hours, with the exception of the last hour, di-tert-butyl peroxide was added at 30-minute intervals (here, 30 portions, total amount 2.8% by weight relative to the total weight of 1-decene and methacrylate monomers).

Example 2

(6) 109 g of 1-decene, 87 g of IDMA, and 104 g of LIMA were charged into a 500 mL 4-necked round bottom flask. 0.225 g of 5,10,15,20-Tetraphenyl Porphine Cobalt(II) was then added to the flask. The contents of the flask were mixed using an overhead stirrer, inerted with nitrogen, and heated to 140 C. Once the mixture reached temperature and the cobalt catalyst appeared to be dissolved, 2.8 g of initiator solution comprising 50% by weight 2,2-bis-tert-butyl-peroxybutane was added to the flask using a syringe through a rubber septum. The reaction was allowed to proceed for 30 minutes. Five additional shots of 2.8 g of initiator solution were added 30 minutes apart.

(7) Residual monomer was measured by gas chromatography on the resultant polymers to ensure full monomer conversion.

(8) Residual amounts of unreacted 1-decene were removed by via rotary evaporation at 100 C. and less than 15 mm Hg pressure.

Example 3

(9) 109 g of 1-decene, 87 g of IDMA, and 104 g of LIMA were charged into a 500 mL 4-necked round bottom flask. 0.225 g of 5,10,15,20-Tetraphenyl Porphine Cobalt(II) was then added to the flask. The contents of the flask were mixed using an overhead stirrer, inerted with nitrogen, and heated to 140 C. Once the mixture reached temperature and the cobalt catalyst appeared to be dissolved, 1.1 g of initiator solution comprising 50% by weight 2,2-bis-tert-peroxybutane was added to the flask using a syringe through a rubber septum. The reaction was allowed to proceed for 30 minutes. Five additional shots of 1.1 g of initiator solution were added 30 minutes apart.

(10) Residual monomer was measured by gas chromatography on the resultant polymers to ensure full monomer conversion.

(11) Residual amounts of unreacted 1-decene were removed by via rotary evaporation at 100 C. and less than 15 mm Hg pressure.

Example 4

(12) 90 g of 1-decene and 210 g of LMA were charged into a 500 mL 4-necked round bottom flask. 0.225 g of 5,10,15,20-Tetraphenyl Porphine Cobalt(II) was then added to the flask. The contents of the flask were mixed using an overhead stirrer, inerted with nitrogen, and heated to 140 C. Once the mixture reached temperature and the cobalt catalyst appeared to be dissolved, 1.1 g of initiator solution comprising 50% by weight 2,2-bis-tert-butyl-peroxybutane was added to the flask using a syringe through a rubber septum. The reaction was allowed to proceed for 30 minutes. Five additional shots of 1.1 g of initiator solution were added 30 minutes apart.

(13) Residual monomer was measured by gas chromatography on the resultant polymers to ensure full monomer conversion.

(14) Residual amounts of unreacted 1-decene were removed by via rotary evaporation at 100 C. and less than 15 mm Hg pressure

Example 5

(15) 90 g of 1-decene and 210 g of LMA were charged into a 500 mL 4-necked round bottom flask. 0.225 g of 5,10,15,20-Tetraphenyl Porphine Cobalt(II) was then added to the flask. The contents of the flask were mixed using an overhead stirrer, inerted with nitrogen, and heated to 140 C. Once the mixture reached temperature and the cobalt catalyst appeared to be dissolved, 1.1 g of initiator solution comprising 50% by weight of 2,2-bis-tert-butyl-peroxybutane was added to the flask using a syringe through a rubber septum. The reaction was allowed to proceed for 30 minutes. Five additional shots of 1.1 g of initiator solution were added 30 minutes apart.

(16) Residual monomer was measured by gas chromatography on the resultant polymers to ensure full monomer conversion.

(17) Residual amounts of unreacted 1-decene were removed by via rotary evaporation at 100 C. and less than 15 mm Hg pressure

Comparative Example 6

(18) 250 g of LMA were charged into a 500 mL 4-necked round bottom flask. 0.188 g of 5,10,15,20-Tetraphenyl Porphine Cobalt(II) was then added to the flask. The contents of the flask were mixed using an overhead stirrer, inerted with nitrogen, and heated to 90 C. Once the mixture reached temperature and the cobalt catalyst appeared to be dissolved, 1 g of initiator solution comprising 25% by weight 2-(2-cyanobutan-2-yldiazenyl)-2-methylbutanenitrile (Vazo67) in diisobutyl ketone was added to the flask using a syringe through a rubber septum. The reaction was allowed to proceed for 60 minutes. Two additional shots of 1 g of initiator solution were added 60 minutes apart. The reaction was allowed to hold for one hour after the final addition of initiator.

Measurements of Viscosity, Molecular Weight, and Sonic Shear Stability

(19) The kinematic viscosities of the polymers were measured according to ASTM D 445. The polymer molecular weights were measured by gel permeation chromatography (GPC) calibrated using poly(methyl-methacrylate) standards. The sonic shear stability was determined according to ASTM D 5621. The pour point was determined according to ASTM D 6749. The viscosity index was determined according to ASTM D 2270.

(20) Examples 2 to 5 demonstrate that the use of a cobalt based catalytic chain transfer agent for the polymerization of methacrylate and 1-alkene monomers yields polymers with a kinematic viscosity of less than 25 mm.sup.2/s measured at 100 C. according to ASTM D 445 (table 1). Comparative example 1 demonstrates that this is not achievable without the cobalt based chain transfer agent. An additional beneficial feature when using the method of the present invention is a greater efficiency of the 1-decene to reduce viscosity, such that only half the charge of 1-decene is required in example 5 as compared to comparative example 1. These features demonstrate the utility of the inventive method to enable the preparation of polymers with lower viscosities and a high methacrylate to 1-alkene ratio.

(21) Molecular weight data show that the extremely low molecular weight methacrylate-decene polymers of examples 2 to 5 have a degree of polymerization of about 5, whereas previous cobalt based catalytic chain transfer polymerizations of lauryl-methacrylate without the alpha-olefin comonomer showed an average degree of polymerization of about 9. A direct comparison of example 4 and comparative example 6 shows the impact of incorporating 1-decene in the presence of a cobalt based catalytic chain transfer agent on polymer M.sub.w (from 4400 g/mol to 1800 g/mol) and product viscosity at 100 C. (from 40 mm.sup.2/s to 9 mm.sup.2/s). Indeed, it was observed that polymers which are prepared by CCT polymerization using cobalt(II) as a catalytic chain transfer agent, but without the presence of a 1-alkene component, have kinematic viscosity values which quickly reach a plateau, even by increasing the amount of cobalt catalytic chain transfer agent, and which are not getting to a lower kinematic viscosity value than 40 mm.sup.2/s at 100 C. according to ASTM D 445 (see below Examples 6 to 9 in Table 1 and Table 1 continued). Said decreasing activity of the Cobalt catalytic transfer agent was also observed and commented in the publication Smirnov et al, Polym. Sci. 1981, A23, 1158.

(22) On the contrary, the inventive method, combining CCT polymerization using cobalt(II) as a catalytic chain transfer agent in the presence of a 1-alkene component, surprisingly allows preparing polymer compositions with special properties, namely, a kinematic viscosity of less than 25 mm.sup.2/s measured at 100 C. according to ASTM D 445 (Examples 2 to 5 in Table 1).

(23) The direct comparison of examples 2 and 3 shows that a reduction in the amount of radical initiator yields a lower viscosity of the product polymers. This is contrary to what is normally observed in free radical polymerization, where a reduction in polymerization initiator typically results in higher viscosity. This effect is beneficial in helping reduce the overall amount of initiator by-products that may be present in the product polymer. Examples 2 and 3 also show that a reduction in the amount of radical initiator lowers the pour point of the product polymer.

(24) As the different pour points of examples 2 to 5 indicate, the pour point may also be tuned by varying the composition of the monomer mixture, in particular by varying the amount of 1-alkene.

(25) TABLE-US-00001 TABLE 1 Viscosimetric data of examples 1 to 6. The amounts given are relative to the total weight of the sum of 1-decene and the methacrylate monomers. Example 1 2 3 4 5 6 1-decene [% by weight] 36 36 36 30 30 0 C.sub.10 methacrylate [% by weight] 29 29 29 0 0 0 C.sub.12 methacrylate [% by weight] 9 9 9 51 51 72 C.sub.13 methacrylate [% by weight] 10 10 10 0 0 0 C.sub.14 methacrylate [% by weight] 10 10 10 19 19 28 C.sub.15 methacrylate [% by weight] 6 6 6 0 0 0 Co(II) [ppm by weight] 0 66 66 66 66 66 Initiator [% by weight] 2.8 2.8 1.1 1.1 1.1 0.3 M.sub.W [kg/mol] 4.0 2.4 1.8 1.8 1.8 4.4 Kinematic viscosity at 100 C. [mm.sup.2/s] 45.1 19.6 11.6 9.07 9.10 40 Kinematic viscosity at 40 C. [mm.sup.2/s] 489 176 84.1 54.5 52.7 437 Viscosity Index 146 128 129 147 154 140 Pour point [ C.] 43.2 39 48 27 27 ND Example 7 8 9 1-decene [% by weight] 0 0 0 C.sub.10 methacrylate [% by weight] 0 0 0 C.sub.12 methacrylate [% by weight] 72 72 72 C.sub.13 methacrylate [% by weight] 0 0 0 C.sub.14 methacrylate [% by weight] 28 28 28 C.sub.15 methacrylate [% by weight] 0 0 0 Co(II) [ppm by weight] 26 40 162 Initiator [% by weight] 0.3 0.3 0.3 M.sub.W [kg/mol] 10.6 6.2 4.4 Kinematic viscosity at 100 C. [mm.sup.2/s] 192 75 40 Kinematic viscosity at 40 C. [mm.sup.2/s] Viscosity Index Pour point [ C.]

(26) Table 2 shows the properties of two commercially available group IV polyalphaolefin base oils (Spectrasyn 10) and ester-based fluids (Esterex TM101) in comparison to examples 3 and 4. The data show that examples 3 and 4 deliver viscosity indices greater than those of the commercial products, and are able to provide base fluids with excellent pour points.

(27) TABLE-US-00002 TABLE 2 Comparison of commercial base fluids to examples 3 and 4. Spectrasyn Esterex Example Product 10 TM101 3 Example 4 Kinematic viscosity 10 9.8 11.6 9.07 at 100 C. [mm.sup.2/s] Kinematic viscosity 66 89 84.1 54.5 at 40 C. [mm.sup.2/s] Viscosity Index 137 86 129 147 Pour Point [ C.] 48 36 48 27