阅读说明：本技术 液态乙烯共聚物的高压聚合方法 (High pressure polymerization of liquid ethylene copolymers ) 是由 M·温德克尔 I·加西亚卡斯特罗 J·斯特里特马特 K·盖耶 W·格拉巴斯 M·舍尔 R 于 2019-03-14 设计创作，主要内容包括：本发明涉及一种制备液态乙烯共聚物的连续高压聚合方法,所述液态乙烯共聚物以聚合形式包含20-60重量％的乙烯和至少20重量％的丙烯酸酯(其选自(甲基)丙烯酸C<Sub>1</Sub>-C<Sub>22</Sub>烷基酯),其中使包含乙烯和丙烯酸酯的单体进料在至少2重量％的链转移剂存在下聚合。本发明还涉及可通过该聚合方法得到的液态乙烯共聚物；和包含可通过该聚合方法得到的液态乙烯共聚物的润滑剂；和一种用于减少移动表面之间摩擦的方法,该方法包括使表面与润滑剂或与乙烯共聚物接触的步骤。(The present invention relates to a continuous high pressure polymerization process for preparing a liquid ethylene copolymer comprising, in polymerized form, from 20 to 60% by weight of ethylene and at least 20% by weight of an acrylic acid ester selected from (meth) acrylic acid C 1 ‑C 22 Alkyl ester) wherein a monomer feed comprising ethylene and an acrylate is polymerized in the presence of at least 2 wt.% of a chain transfer agent. The invention also relates to a liquid ethylene copolymer obtainable by the polymerization process; and a lubricant comprising a liquid ethylene copolymer obtainable by the polymerization process; and a method for reducing friction between moving surfaces, the method comprising the step of contacting the surfaces with a lubricant or with an ethylene copolymer.)

1. A continuous high pressure polymerization process for the preparation of a liquid ethylene copolymer comprising in polymerized form

-20-60% by weight of ethylene; and

at least 20% by weight of an acrylate chosen from (meth) acrylic acid C₁-C₂₂An alkyl ester, a carboxylic acid,

wherein a monomer feed comprising ethylene and an acrylate is polymerized in the presence of at least 2 wt% of a chain transfer agent.

2. The polymerization process of claim 1, wherein the chain transfer agent is a saturated or unsaturated hydrocarbon, an aliphatic ketone, an aliphatic aldehyde, or hydrogen, or mixtures thereof.

3. The polymerization process of claim 1 or 2, wherein the chain transfer agent is propionaldehyde, methyl ethyl ketone, or hydrogen, or mixtures thereof.

4. The polymerization process according to any one of claims 1 to 3, wherein the monomer feed is polymerized in the presence of 4 to 18 wt.%, preferably 6 to 15 wt.%, in particular 9 to 13 wt.% of a chain transfer agent.

5. The polymerization process according to any one of claims 1 to 4, wherein the polymerization is carried out in a stirred autoclave.

6. The polymerization process according to any one of claims 1 to 5, wherein the reaction temperature is from 150 to 300 ℃, preferably from 170 to 250 ℃, in particular from 190 to 230 ℃.

7. The polymerization process according to any one of claims 1 to 6, wherein the polymerization process is carried out at a pressure of from 1000 to 4000 bar, preferably from 1200 to 2500 bar, in particular from 1600 to 2000 bar.

8. The polymerization process according to any one of claims 1 to 7, wherein the ethylene copolymer has a pour point of less than 25 ℃, preferably less than 20 ℃, in particular less than 15 ℃.

9. The polymerization process according to any one of claims 1 to 8, wherein the ethylene copolymer comprises, in polymerized form, from 25 to 55% by weight of ethylene.

10. The polymerization process according to any one of claims 1 to 9, wherein the ethylene copolymer comprises in polymerized form at least 30% by weight, preferably at least 40% by weight, in particular at least 50% by weight, of acrylate.

11. The polymerization process according to any one of claims 1 to 10, wherein the ethylene copolymer contains no other monomers than ethylene and acrylic acid esters.

12. The polymerization process of any one of claims 1-11, wherein the acrylate comprises

-is selected from (meth) acrylic acid C₁-C₅Polar acrylates of alkyl esters, and

-is selected from (meth) acrylic acid C₆-C₂₂Non-polar acrylates of alkyl esters.

13. The polymerization process of claim 12, wherein the ethylene copolymer comprises in polymerized form

25 to 55% by weight of ethylene,

At least 20% by weight of a polar acrylate, and

-at least 15 wt% of a non-polar acrylate.

14. The polymerization process according to any one of claims 1 to 13, wherein the ethylene copolymer comprises, in polymerized form, less than 2 mol%, preferably less than 1 mol%, of vinyl esters of the formula (I)

Wherein R is^c、R^dAnd R^eEach independently is H or C₁-C₄Alkyl, and R^fIs C₁-C₂₀An alkyl group.

15. A liquid ethylene copolymer obtainable by a polymerization process as defined in any one of the preceding claims.

16. A lubricant comprising a liquid ethylene copolymer obtainable by a polymerization process as defined in any one of the preceding claims.

17. A method of reducing friction between moving surfaces comprising the step of contacting said surfaces with a lubricant as defined in claim 16 or with an ethylene copolymer as defined in claim 15.

Examples

NBA: n-butyl acrylate is used as the monomer,

EHA: 2-ethylhexyl acrylate, commercially available from BASF SE.

PHA: 2-propylheptyl acrylate, commercially available from BASF SE.

LA: lauryl acrylate (acrylic acid C)₁₂:C₁₄Mixtures of alkyl esters 60: 40)

C17A: heptadecyl acrylate based on a mixture of branched C17 alkanols, commercially available from BASF SE.

Preparation of the copolymer

Continuous copolymerization is carried out using an autoclave of the type described in the literature (M.Buback et al, chem.Ing.Tech.1994, 66, 510-513).

Ethylene was continuously fed to the first compressor up to about 250 bar. Separately from this, a quantity of acrylic ester is also continuously compressed to an intermediate pressure of 250 bar and mixed with the ethylene feed. The ethylene acrylate mixture was further compressed using a second compressor. The reaction mixture was placed in a 1 liter autoclave with a pressure and temperature also according to table 1. The desired temperature is controlled depending on the amount of tert-amyl peroxypivalate initiator in isodecane, which is introduced into the autoclave separately from the monomer feed (about 1000-1500 ml/h).

Separately from this, a quantity of the chain transfer agent Propionaldehyde (PA) or Methyl Ethyl Ketone (MEK) is first compressed to a medium pressure of 250 bar and then fed continuously into the autoclave by means of a further compressor at the reaction pressure.

The output of the reaction in Table 1 is generally about 5 to 6kg/h at a conversion of 30 to 45% by weight, based on the ethylene feed. Details of the reaction conditions are summarized in table 1, and analytical data of the liquid ethylene copolymers are summarized in table 2. The modifier feed in table 1 is referred to as propionaldehyde, if not otherwise stated.

Table 1: preparation of liquid ethylene copolymers

Characterization of liquid ethylene copolymers

The number average molecular weight distribution Mn and the weight average molecular weight distribution Mw were determined by GPC. The polydispersity was calculated as PD ═ (Mw/Mn). GPC analysis was carried out using an RI detector, a PLgel MIXED-B column (column temperature 35 ℃) and THF containing 0.1% trifluoroacetic acid as the elution medium. Calibration was performed using a very narrow distribution polystyrene standard with a molecular weight M of 580-6,870,000g/mol from Polymer Laboratories.

Cloud Point CP is determined according to ISO 3015. Pour point PP is determined according to ASTM D97.

The results show that all ethylene copolymers are liquid at room temperature and have a pour point below 25 ℃.

The results further show that all ethylene copolymers tend to have good low temperature properties due to their low cloud point.

The amount of monomers present in the polymer in polymerized form is determined by H-NMR.

Table 2: analytical data of the copolymer

Viscosity and appearance of liquid ethylene copolymers

Kinematic viscosities at 40 ℃ (V40) and 100 ℃ (V100) were determined according to ASTM D445. Viscosity Index (VI) was determined according to ASTM D2270. The appearance of the liquid ethylene copolymer was determined visually.

The results indicate that the ethylene copolymer has the desired high kinematic viscosity and the desired high viscosity index.

Table 3: viscosity data

Miscibility with polyalphaolefins

The liquid ethylene copolymer was mixed with a polyalphaolefin having a kinematic viscosity of about 6cSt at 100 ℃ at a weight ratio of 50:50 at room temperature and mixed by tumbling at room temperature for 12 hours. The appearance of the mixture was again observed after homogenization and after 24 hours. When no phase separation was observed after 24 hours, the copolymer was considered to be compatible with the polyalphaolefin.

The results show that several ethylene copolymers are miscible with very non-polar low viscosity polyalphaolefins, typically based on poly (1-decene).

Table 4: miscibility with PAO-6 (50:50 vol%)