KR101153015B1 - A preparation method of ethylene-acrylate copolymer - Google Patents

Abstract

The present invention relates to a method for preparing an ethylene-acrylate copolymer, and more particularly, to polymerizing an ethylene monomer and an acrylate comonomer in the presence of a metal oxide that can be recovered and reused by a physical method. It relates to a method for producing an ethylene-acrylate copolymer, characterized in that.

According to the present invention, the process is simple, the equipment can be safely operated, and the ethylene-acrylate copolymer having the same level of polar comonomer content can be prepared while replacing the conventional Lewis acid. Easy to control In addition, the filtering device alone can recover and reuse nearly 100% of the metal oxide, which significantly lowers manufacturing costs and improves process stability against moisture, thereby facilitating industrial operation.

Ethylene-acrylate copolymers, metal oxides, recovery,

Description

Process for producing ethylene-acrylate copolymer {A PREPARATION METHOD OF ETHYLENE-ACRYLATE COPOLYMER}

The present invention relates to a method for producing an ethylene-acrylate copolymer, and more particularly, to replace the conventional Lewis acid by using a metal oxide that can be recovered and reused by physical methods, while having the same level of polar comonomer content. It relates to a method for producing an ethylene-acrylate copolymer having a copolymer.

When copolymerized with comonomers such as alkyl acrylates or alkyl methacrylates, olefins can form polymers with different physical properties that cannot be obtained from simple polyethylene. For example, some properties, such as adhesion, low temperature toughness, and the like, can be significantly improved as the content of comonomer (s) increases. Therefore, the development of copolymers in which these olefins and other comonomers are mixed has been the subject of much research in recent years.

Conventionally, it has been common technique to prepare olefin-alkyl acrylate or olefin-alkyl methacrylate copolymers by high temperature and high pressure reaction. Therefore, a method is disclosed in which a reaction is carried out by simultaneously introducing an olefin and an acrylate monomer under severe conditions of 1000 to 100 ° C. using a tubular reactor or an autoclave reactor to withstand high temperature and high pressure. The copolymer obtained under these conditions is a copolymer containing 3 to 35% of an acrylic monomer which is a polar monomer on an olefin basis.

However, in order to implement such high temperature and high pressure conditions, an additional device for safety of an operator, such as a primary compressor, a secondary compressor, and a special reactor, is required. In addition, due to the harsh process conditions, a lot of constraints are required to change the composition change of the copolymer in the desired direction, the prepared copolymer has a limitation that the content of the polar monomer is not high.

Therefore, a method using a metal complex compound and a controlled radical polymerization method have been proposed to prepare a copolymer having high crystallinity and a high degree of polar comonomer without crystallinity, while avoiding high temperature and high pressure polymerization conditions. . In particular, the method of preparing a polar copolymer using Lewis acid has an advantage of obtaining a copolymer having a higher content of the polar vinyl monomer than the olefin content. Korean Patent No. 2006-0038843 (filed April 28, 2006) discloses related methods.

However, the above methods have to remove the metal complex or the metal ions of Lewis acid to obtain the final copolymer polymerized polymer after the polymerization is completed, and inevitably undergo a chemical reaction step. Japanese Patent Application Laid-Open No. 194-0287256 (published 14.10.11), 2005-105073 (published Apr. 21, 2005), 2002-020480 (published Jan. 23, 2002) and US Patent No. 5,248,833 (published Sep. 28, 1993) ), EP 1053974 (published on November 22, 2000) and the like disclose a method for removing metal ions.

A commonly used method for removing metal ions is to extract metal ions remaining in the polymer solution with a mixed solution of excess hydrochloric acid and ethanol. Since this method uses strong acid, the molecular weight of the copolymer may be reduced, and the use of acid / base in the chemical process may require the addition of a unit process necessary for neutralization, safety of equipment, increase of equipment cost, and environmental problems. This can be presented.

Another method for removing metal ions is a method of forming a metal compound and a chelating compound using a chelating agent to precipitate the precipitate, and then filtering and removing the metal ion. In this method, since a small amount of the chelating agent is added, the amount of the chelating agent remaining in the polymer solution after the reaction is small, and the boiling point of the chelating agent can be used to remove the chelating agent remaining in the copolymer through heating and reduced pressure. Korean Patent No. 2005-0111412 (filed Nov. 21, 2005) discloses a method that does not require an additional filtration process for removal of a chelating compound by selecting an appropriate chelating agent, a solvent, and a nonsolvent.

However, the amount of Lewis acid added to increase the content of the non-polar monomer is considerable, which can lead to equipment corrosion and operation risks. In addition, there is a problem that increases the manufacturing cost because it is impossible to reuse.

In order to solve the problems of the prior art as described above, the present invention replaces the conventional Lewis acid by using a metal oxide that can be recovered and reused by a physical method, while having an ethylene-acrylate system having an equivalent level of polar comonomer content. It is an object to provide a method for producing a copolymer.

These and other objects of the present invention can be achieved by the present invention described below.

In order to achieve the above object, the present inventors have intensively studied, and when polymerizing an ethylene monomer and an acrylic comonomer using a metal oxide, it is possible to avoid the conditions of high temperature and high pressure, replacing the conventional Lewis acid At the same time, it was possible to prepare an ethylene-acrylate based copolymer having an equivalent level of polar comonomer content. In addition, it was confirmed that the physical method using only a filtration device can recover almost 100% of the metal oxide, and that the recovered metal oxide can be used for polymerization again, thereby completing the present invention.

The present invention provides a method for producing an ethylene-acrylate copolymer, comprising the step of polymerizing an ethylene monomer and an acrylate comonomer in the presence of a metal oxide.

The metal oxide may be recovered by a physical method and reused in the preparation of the ethylene-acrylate copolymer.

The present invention also provides an ethylene-acrylate copolymer prepared by the above production method.

Hereinafter, the present invention will be described in detail.

The method for preparing the ethylene-acrylate copolymer of the present invention includes (a) polymerizing ethylene and an acrylate comonomer in the presence of a metal oxide that can be recovered and reused by a physical method.

The acrylate-based comonomer is preferably a compound represented by the following formula (1).

In Formula 1, R ₁ , R ₂ and R ₃ are each independently a monovalent hydrocarbon group having 1 to 30 carbon atoms which may include a hydrogen atom or a hetero atom, and R ₄ is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms to be.

Specific examples of the acrylate-based comonomer include one or more selected from the group consisting of alkyl acrylates, alkyl methacrylates, and alkyl butacrylates, including alkyl groups having 1 to 12 carbon atoms in a straight or branched chain. This is preferable.

Metal oxides can be recovered by physical methods and can be reused during polymerization.

As the metal oxides, alkaline earth metals, transition metals, group 13 and 14 metal oxides, and the like are preferable. Specific examples include aluminum oxide (Al ₂ O ₃ ), yttrium oxide (Y ₂ O ₃ ), zinc oxide (ZrO ₂ ), hafnium oxide (HfO ₂ ), silicon oxide (SiO ₂ ), and boron oxide (B ₂ O ₃ ), cesium oxide (CeO ₂ ), dysprosium oxide (Dy ₂ O ₃ ), erbium oxide (Er ₂ O ₃ ), europium oxide (Eu ₂ O ₃ ), gadolinium oxide (Gd ₂ O ₃ ), holmium oxide (Ho ₂ O ₃ ), lanthanum oxide (La ₂ O ₃ ), lutetium oxide (Lu ₂ O ₃ ), neodymium oxide (Nd ₂ O ₃ ), praseodymium oxide (Pr ₆ O ₁₁ ), samarium oxide (Sm ₂ O ₃ ), Terbium oxide (Tb ₂ O ₃ ), thorium oxide (Th ₄ O ₇ ), thorium oxide (Tm ₂ O ₃ ), ytterbium oxide (Yb ₂ O ₃ ), tin oxide (SnO), titanium oxide (TiO ₂ ), dysprosium Aluminate (Dy ₃ Al ₅ O ₁₂ ), Yttnium Aluminate (Y ₃ Al ₅ O ₁₂ ), Aluminum Titanate (Al ₂ O ₃ ? TiO ₂ ), Aluminum Silicate (3Al ₂ O ₃ ? 2SiO ₂ ), Calcium Titanate (CaTiO ₃ ), calcium zirconate (CaZrO ₃ ), iron titanate (FeTiO ₃ ), magnesium aluminate (MgO Al ₂ O ₃ ), cesium aluminate (CeAl ₁₁ O ₁₈ ), aluminum sulfate (Al ₂ (SO ₄ ) ₃ ), and at least one member selected from the group consisting of aluminum phosphate (AlPO ₄ ).

The metal oxide may be used in a ratio of 0.1 to 10 moles based on 1 mole of the acrylate comonomer, and is preferably used in a ratio of 0.5 to 3 moles. If the amount is less than 0.1 molar ratio, there is a problem that the amount of ethylene introduced is less, and if it exceeds 10 molar ratio, there is a problem that stirring is difficult due to excessive metal oxide particles.

In the presence of the metal oxide as described above, a polymerization solvent, a polymerization initiator, and the like commonly used in the art may be added to polymerize the ethylene monomer and the acrylate comonomer.

As the polymerization solvent, one or more selected from the group consisting of toluene, chlorobenzene, n-hexane, n-heptane, tetrahydrofuran, chloroform and methylene chloride can be used. The polymerization solvent may be used in a 0.5 to 5.0 volume ratio, preferably 1.5 to 3.5 volume ratio based on the total volume of the acrylate-based comonomer. If the amount is less than 0.5 volume ratio, there is a problem that the amount of ethylene introduced is less, when the amount exceeds 5.0 volume ratio, there is a problem that the molecular weight of the produced copolymer is less.

As the polymerization initiator, one or more selected from the group consisting of peroxides and azo compounds can be used. The polymerization initiator may be used in 0.001 to 1.0 molar ratio, preferably 0.01 to 0.1 molar ratio based on 1 mole of the acrylic comonomer. If the amount is less than 0.001 molar ratio, there is a problem that the yield of polymerization is lowered, and if it exceeds 0.1 mol%, there is a problem that a copolymer is not formed.

The polymerization is preferably carried out at a pressure of atmospheric pressure to 200 atm, and a temperature of 30 to 150 ° C, more preferably at a pressure of 5 to 50 atm, and a temperature of 50 to 120 ° C. If the pressure is less than the atmospheric pressure there is a problem that ethylene is not introduced, if the pressure exceeds 200 atm there is a problem that the reaction apparatus is complicated. In addition, when the temperature is less than 30 ℃ there is a problem that the copolymer is not polymerized, if it exceeds 150 ℃ there is a problem that the polymerization reaction occurs rapidly and difficult to control.

The method for preparing an olefin-acrylate copolymer of the present invention may further include (b) recovering the metal oxide from the polymerization solution after the polymerization step as described above is completed.

The recovery step of the metal oxide is a method comprising (i) filtering the polymerization solution to separate the metal oxide, and (ii) washing the separated metal oxide with a solvent, followed by drying.

The recovery amount of the metal oxide recovered in the recovery step may be 90 to 100% based on the content of the metal oxide used for the first time.

In addition, a solvent may be added to the polymerization solution in which the metal oxide is separated by filtration in step (iii) to precipitate the polymer, followed by curing, to obtain a final olefin-acrylate copolymer. The precipitation is preferably carried out two or more times using a solvent four times or more relative to the total volume of the polymerization solution, and the curing is preferably performed using four times or more water based on the total volume of the polymerization solution.

 The method for producing an ethylene-acrylate copolymer of the present invention may further include (c) reusing the recovered metal oxide to polymerize the ethylene monomer and the acrylate monomer. At this time, the recovered metal oxide can be reused about 20 times.

The yield of step (c) of reusing the metal oxide may be 90% or more of the yield of step (a) of using the metal oxide for the first time. In addition, the ethylene monomer content in the ethylene-acrylate copolymer of step (c) may be 90% or more of the ethylene monomer content in the ethylene-acrylate copolymer of step (a).

The present invention provides an ethylene-acrylate copolymer prepared by the above method.

The ethylene-acrylate copolymer preferably has a composition ratio of 5 to 50 mol% of ethylene monomers and 50 to 95 mol% of acrylate monomers.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the present invention. Such variations and modifications are intended to be within the scope of the appended claims.

[Example]

Example 1

A 2 L high pressure reactor was vacuumed and then filled with argon. 114.4 g (1.12 mol) of aluminum oxide (Al ₂ O ₃ ), 300 ml of toluene, and 120 ml (1.12 mol) of methyl methacrylate (MMA) were added to an argon atmosphere reactor. Then, 1.12 mmol of azobisisobutyronitrile (AIBN), an initiator, dissolved in toluene was added thereto. Subsequently, after charging 35 bar of ethylene, the reactor temperature was raised to 70 ° C. and the polymerization was performed for 20 hours with stirring at 250 rpm using a mechanical stirrer.

After the polymerization reaction was completed, the reaction temperature was dropped to room temperature, and then filtered to recover aluminum oxide. Thereafter, the polymer solution from which the metal oxide was removed was dropped in non-solvent ethanol to precipitate the polymer in the solid phase. The solid phase was allowed to settle, the supernatant was removed, ethanol was added to wash once more, water was added to stir the particles, and the mixture was stirred and filtered to recover the copolymer. The recovered copolymer was dried in a vacuum oven at 60 ° C. for one day.

Example 2

Except that in Example 1, the content was adjusted so that the molar ratio of MMA / Al ₂ O ₃ to 2 was carried out in the same manner as in Example 1.

Example 3

Except that the content was adjusted in Example 1 to the molar ratio of AIBN / MMA to 0.004 was carried out in the same manner as in Example 1.

Example 4

Except that the reaction pressure was adjusted to 25 bar in Example 1 was carried out in the same manner as in Example 1.

Example 5

Except that the reaction temperature in Example 1 was adjusted to 60 ℃ was carried out in the same manner as in Example 1.

division MMA / Al ₂ O ₃ (molar ratio) AIBN / MMA (molar ratio) Pressure (bar) Temperature (℃) Time (hr) Example 1 One 0.001 35 70 20 Example 2 2 0.001 35 70 20 Example 3 One 0.004 35 70 20 Example 4 One 0.001 25 70 20 Example 5 One 0.001 35 60 20

The physical properties of the ethylene-acrylate copolymers prepared in Examples 1 to 5 were measured by the following method, and the results are shown in Table 2 below.

* Ethylene content (mol%)-It measured using 500 Hz nuclear magnetic resonance method (NMR, Varian company make).

* Glass transition temperature (Tg, ℃) and pyrolysis temperature (Td, ℃)-was measured using a differential scanning calorimeter (DSC).

* Weight average molecular weight (Mw) and molecular weight distribution (polydispersity index, PDI)-was measured using gel permeation chromatography (GPC, Waters).

Recovered metal oxide (Al ₂ O ₃ ) content (% by weight)-After washing and drying the filtered aluminum oxide, the recovery content of the total amount of aluminum oxide used for the first time was measured. Recovery content measurement was quantified using a scale (manufactured by Metro Toledo) capable of measuring up to 100 mg.

division Ethylene content
(mole%) Tg (占 폚) Td (℃) Mw PDI Recovered Al ₂ O ₃ Content
(weight%) Example 1 35 75 440 150,000 1.8 90 Example 2 41 69 444 141,000 1.7 91 Example 3 33 76 439 54,000 1.6 96 Example 4 19 85 431 162,000 1.8 92 Example 5 34 73 439 174,000 1.8 90

As shown in Table 2 above, when the ethylene monomer and the acrylate-based comonomer are polymerized in the presence of a metal oxide, the ethylene-acrylate-based air having a content of 50-95 mol% of the acrylate-based polar comonomer The coalescence could be prepared. In addition, it was confirmed that the metal oxide can be recovered to 90% by weight or more of the initial usage by a physical method using only a simple filtration device.

Example 6

After the polymerization reaction was completed in Example 3, it was carried out in the same manner as in Example 3 except that the recovered Al ₂ O ₃ was reused once.

Example 7

After the polymerization reaction was completed in Example 3, it was carried out in the same manner as in Example 3 except that the recovered Al ₂ O ₃ was reused twice.

Example 8

On the completion of the polymerization in Example 3, it was carried out as Example 3, except for the number of Al ₂ O ₃ to a re-use three times.

Example 9

After the polymerization reaction was completed in Example 3, it was carried out in the same manner as in Example 3 except that the recovered Al ₂ O ₃ was reused 20 times.

The physical properties of the ethylene-acrylate copolymers prepared in Examples 6 to 9 were measured, and the results are shown in Table 3 below.

division Number of uses of metal oxides Ethylene content
(mole%) Tg (占 폚) Td (℃) Mw PDI Recovered Al ₂ O ₃ Content
(weight%) Example 3 First use 33 76 439 54,000 1.6 96 Example 6 1 time 34 77 441 64,000 1.8 95 Example 7 Episode 2 33 76 439 51,000 1.7 94 Example 8 3rd time 32 74 436 55,000 1.6 94 Example 9 20 times 30 70 439 59,000 1.6 93

As shown in Table 3, after the polymerization of the ethylene monomer and the acrylate comonomer is completed according to the present invention, the metal oxide is separated by filtration and reused in the polymerization reaction of the ethylene monomer and the acrylic comonomer, Compared to the first use, the yield is not lowered, it was confirmed that the physical properties of the prepared copolymer is also similar.

As described above, according to the present invention, the process is simple, the equipment can be safely operated, and the ethylene-acrylate copolymer having the same level of polar comonomer content can be prepared while replacing the conventional Lewis acid. It is easy to control the physical properties of the copolymer. In addition, since only 100% of the metal oxide can be recovered and reused only by the filtration device, not only the manufacturing cost is significantly lowered but also the process stability against moisture is improved, and industrial operation is easy.

Claims (18)

(a) polymerizing an ethylene monomer and an acrylate comonomer in the presence of at least one metal oxide selected from the group consisting of alkaline earth metals, transition metals, group 13 metals and group 14 metal oxides; And (b) recovering the metal oxide from the polymerization solution prepared in step (a) by a physical method; In step (b), (Iii) filtering the polymerization solution to separate the metal oxide, and (Ii) washing the separated metal oxide with a solvent, followed by drying. Method for producing ethylene-acrylate copolymer. delete The method of claim 1, The metal oxide is aluminum oxide, yttrium oxide, zinc oxide, hafnium oxide, silicon oxide, boron oxide, cesium oxide, dysprosium oxide, erbium oxide, europium oxide, gadolinium oxide, holmium oxide, lanthanum oxide, ruthetium oxide, neodymium oxide Praseodymium oxide, samarium oxide, terbium oxide, thorium oxide, thulium oxide, ytterbium oxide, tin oxide, titanium oxide, dysprosium aluminate, yttrium aluminate, aluminum titanate, aluminum silicate, calcium titanate, calcium zirconate, At least one member selected from the group consisting of iron titanate, magnesium aluminate, and cesium aluminate. Method for producing ethylene-acrylate copolymer. delete delete The method of claim 1, The recovery amount of the metal oxide is characterized in that 90 to 100% by weight of the metal oxide content of the step (a) Method for producing ethylene-acrylate copolymer. The method of claim 1, The manufacturing method further comprises the step of polymerizing the ethylene monomer and the acrylate comonomer by (c) reusing the metal oxide recovered in the step (b). Method for producing ethylene-acrylate copolymer. The method of claim 7, wherein The yield of step (c) is characterized in that more than 90% by weight of the step (a) yield Method for producing ethylene-acrylate copolymer. The method of claim 7, wherein The ethylene monomer content in the ethylene-acrylate copolymer of step (c) is 90% by weight or more of the ethylene monomer content in the ethylene-acrylate copolymer of step (a). Method for producing ethylene-acrylate copolymer. The method of claim 1, The polymerization is carried out at a pressure of atmospheric pressure to 200 atm, and temperature conditions of 30 to 150 ℃ Method for producing ethylene-acrylate copolymer. The method of claim 1, The polymerization is carried out using a polymerization solvent and a polymerization initiator. Method for producing ethylene-acrylate copolymer. 12. The method of claim 11, The polymerization solvent is at least one member selected from the group consisting of toluene, chlorobenzene, n-hexane, n-heptane, tetrahydrofuran, chloroform and methylene chloride. Method for producing ethylene-acrylate copolymer. The method of claim 11 or 12, The amount of the polymerization solvent is used, characterized in that 0.5 to 5.0 volume ratio based on the total volume of the acrylate-based comonomer. Method for producing ethylene-acrylate copolymer. 12. The method of claim 11, The polymerization initiator is at least one member selected from the group consisting of peroxides and azo compounds Method for producing ethylene-acrylate copolymer. The method according to claim 11 or 14, The amount of the polymerization initiator used is 0.001 to 1.0 molar ratio, based on 1 mole of acrylic comonomer. Method for producing ethylene-acrylate copolymer. The method of claim 1, The acrylate-based comonomer is represented by the formula (1) [Formula 1]

In Chemical Formula 1, R ₁ , R ₂ and R ₃ are each independently a monovalent hydrocarbon group having 1 to 30 carbon atoms which may include a hydrogen atom or a hetero atom, and R ₄ is represented by a hydrogen atom or an alkyl group having 1 to 6 carbon atoms By Method for producing ethylene-acrylate copolymer. The method according to claim 1 or 16, The acrylate comonomer is at least one member selected from the group consisting of alkyl acrylates, alkyl methacrylates, and alkyl butyacrylates, each containing a linear or branched alkyl group having 1 to 12 carbon atoms. doing Method for producing ethylene-acrylate copolymer. delete