CA1061942A - Manufacture of copolymers of ethylene - Google Patents
Manufacture of copolymers of ethyleneInfo
- Publication number
- CA1061942A CA1061942A CA252,152A CA252152A CA1061942A CA 1061942 A CA1061942 A CA 1061942A CA 252152 A CA252152 A CA 252152A CA 1061942 A CA1061942 A CA 1061942A
- Authority
- CA
- Canada
- Prior art keywords
- ethylene
- tert
- zone
- per cent
- butyl acrylate
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F210/00—Copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond
- C08F210/02—Ethene
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
- C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
- C08F220/04—Acids; Metal salts or ammonium salts thereof
- C08F220/06—Acrylic acid; Methacrylic acid; Metal salts or ammonium salts thereof
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
- C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
- C08F220/10—Esters
- C08F220/12—Esters of monohydric alcohols or phenols
- C08F220/16—Esters of monohydric alcohols or phenols of phenols or of alcohols containing two or more carbon atoms
- C08F220/18—Esters of monohydric alcohols or phenols of phenols or of alcohols containing two or more carbon atoms with acrylic or methacrylic acids
- C08F220/1804—C4-(meth)acrylate, e.g. butyl (meth)acrylate, isobutyl (meth)acrylate or tert-butyl (meth)acrylate
Abstract
ABSTRACT OF THE DISCLOSURE: A process for the manufacture of copolymers of ethylene with butyl acrylate and acrylic acid at from 200 to 350°C under pressures above 800 atmospheres, in which the reaction mixture obtained from the polymerization is kept for from 2 to 10 minutes at from 200 to 250°C under a pressure of 500 at-mospheres. Terpolymers are obtained which may be used as hot-melt adhesives in the form of thin and extremely homogeneous films.
Description
O~Z. ~ 51 MANUFACTU~E OF COPOLYMERS OF ETHYLENE
The invention ~elates to a process for the manufackure o~ co~
polymers of ethylene which çontain, as copolymerizçd units, more than 60 per cent by weight of ethylene, from 1 to 20 per cent by weight of tert.-butyl acrylate and/or tert.-butyl methacrylate and I
from ~ to 10 per cen~ by weight of acrylic acid and/or methacrylic acid, by copolymerization of ethylene and tert -butyl acrylate and/or tert.-buty~ methacrylate at from 200 to 350C at pressures above 800 atmospheres.
~ ~rench Yatent 1,596~991 discloses a process for the manufac-ilO~ ture o~ ethylene copolymers whiqh contain, as copolymerized units, ; a predominant amount of ethylene, an alkene-carboxylic acid of 3 to 12~carbon atoms, minor ~mounts of alkenes of 3 to 8 carbon atoms and, optionallyg esters of alkenecarboxylic acids of ~ to 12 carbon atoms with secondary alkanols of 3 to 8 carbon atoms or tertiary alkanpls of 4 to 8 carbon atoms, and/or further monomers which are copolymerlzable with ethylene. The copolymers are manufactured by copolymerizing monomer mixtures of ethylene, an ester of an alkene-carboxyli¢ acid of ~ to 12 carbon atoms with a secondary alkanol of 3 to~8 carbon atoms or a tertiary alkanol of ~ to 8 carbon atoms ZO and~ optionally~ further monomers which are copolmyerizable with ethyleneJ at pressures of from 100 to 8,ooo atmospheres, and at `~ from 110 to 350C using catalyt,ic amounts of free radical initia-tors. The temperature in the reactor must be at least sufficiently high that the secondary or tertiary ester groups in the polymer o.z 31J351 pyr^~yze partially or completely. Free carboxylic acid groups are then obtained in the polymer, an alkene being eliminated.
However, the homogeneity of the products manufactured by the said process is unsatisfactary. This phenomenon is particularly ob-~ectionable if the polymers are used as hot-melt adhesivqs, because very thin films are required for this purpose, Irregularities in the hot-melt adheslve ~ilm (holes~ specks) are a considerable dis-advantage because they ~educe the adhesion at the interface between the hot-melt adhesive and the material to be honded (eg. polyethylene or metals). If ~he bonded areas are subjected to substantial stressJ
the materials bonded to one another can separate~ for example where the film contains specks. Inhomogeneous films of these polymers give considerable technical difficulties when used in the manufacture of laminates.
A further disadvantage o~ the conventional process is that the copolymer content and melt index of the products obtained show con-siderable variation.
~i It is an ob~ect of the present i~vention to modify the pro-cess described above so that homogeneous ethylene copolymers are ~20 obtained in which the copolymer content and melt index show little variation. It is a further ob~ect that the ethylenq copolymers should be çapable of conversion to very thin films which do not exhibit ob~ectionable irregularities.
~ç have found that these objects are achieved, according to the invention, by passing the reaction mixture, obtained after the polymerization~ into a zone in which the pressure is below 500 atmos~heres and the temperature is from 200 to 250C, the mean re-sidence time of the reaction mixture in the zone belng from 2 to 10 minutes.
In a preferred embodiment of the process9 the temperature of the reaction mixture in the high pressure isolation zone, which is from 200 to 250C, is not allowed to vary by more than ~ 2C.
Acqording to the invention, substantially more homogeneous
The invention ~elates to a process for the manufackure o~ co~
polymers of ethylene which çontain, as copolymerizçd units, more than 60 per cent by weight of ethylene, from 1 to 20 per cent by weight of tert.-butyl acrylate and/or tert.-butyl methacrylate and I
from ~ to 10 per cen~ by weight of acrylic acid and/or methacrylic acid, by copolymerization of ethylene and tert -butyl acrylate and/or tert.-buty~ methacrylate at from 200 to 350C at pressures above 800 atmospheres.
~ ~rench Yatent 1,596~991 discloses a process for the manufac-ilO~ ture o~ ethylene copolymers whiqh contain, as copolymerized units, ; a predominant amount of ethylene, an alkene-carboxylic acid of 3 to 12~carbon atoms, minor ~mounts of alkenes of 3 to 8 carbon atoms and, optionallyg esters of alkenecarboxylic acids of ~ to 12 carbon atoms with secondary alkanols of 3 to 8 carbon atoms or tertiary alkanpls of 4 to 8 carbon atoms, and/or further monomers which are copolymerlzable with ethylene. The copolymers are manufactured by copolymerizing monomer mixtures of ethylene, an ester of an alkene-carboxyli¢ acid of ~ to 12 carbon atoms with a secondary alkanol of 3 to~8 carbon atoms or a tertiary alkanol of ~ to 8 carbon atoms ZO and~ optionally~ further monomers which are copolmyerizable with ethyleneJ at pressures of from 100 to 8,ooo atmospheres, and at `~ from 110 to 350C using catalyt,ic amounts of free radical initia-tors. The temperature in the reactor must be at least sufficiently high that the secondary or tertiary ester groups in the polymer o.z 31J351 pyr^~yze partially or completely. Free carboxylic acid groups are then obtained in the polymer, an alkene being eliminated.
However, the homogeneity of the products manufactured by the said process is unsatisfactary. This phenomenon is particularly ob-~ectionable if the polymers are used as hot-melt adhesivqs, because very thin films are required for this purpose, Irregularities in the hot-melt adheslve ~ilm (holes~ specks) are a considerable dis-advantage because they ~educe the adhesion at the interface between the hot-melt adhesive and the material to be honded (eg. polyethylene or metals). If ~he bonded areas are subjected to substantial stressJ
the materials bonded to one another can separate~ for example where the film contains specks. Inhomogeneous films of these polymers give considerable technical difficulties when used in the manufacture of laminates.
A further disadvantage o~ the conventional process is that the copolymer content and melt index of the products obtained show con-siderable variation.
~i It is an ob~ect of the present i~vention to modify the pro-cess described above so that homogeneous ethylene copolymers are ~20 obtained in which the copolymer content and melt index show little variation. It is a further ob~ect that the ethylenq copolymers should be çapable of conversion to very thin films which do not exhibit ob~ectionable irregularities.
~ç have found that these objects are achieved, according to the invention, by passing the reaction mixture, obtained after the polymerization~ into a zone in which the pressure is below 500 atmos~heres and the temperature is from 200 to 250C, the mean re-sidence time of the reaction mixture in the zone belng from 2 to 10 minutes.
In a preferred embodiment of the process9 the temperature of the reaction mixture in the high pressure isolation zone, which is from 200 to 250C, is not allowed to vary by more than ~ 2C.
Acqording to the invention, substantially more homogeneous
-2-0.~ 31,351 ethylene copolymers are obtained than by the conventional pro-cess.
The ethylene employed for the polymerlzation should be at least 98 per cent pure. tert.-Butyl acrylate and tert.-butyl meth-acrylate are commercially available. The ethylene copolymers, which contain~ as copolymerized units, a predominant amount of ethylene, from 1 to 10 per cent by we~ght of acrylic acid and/or methacrylic acid and ~rom 1 to 20 per cent by weight of tert.-butyl acrylate and~or tert.-butyl methacrylate, are manufactured in conventional equipment, eg. autoclaves or tubul~r reactors. It has proved par-ticularly advantageous to carry out the process continuously. Pre-ferably, the polymerization is qarried out in tubular reactors, cf. Ullmanns Encyklopadie der technischen Chemie, 3rd Edition, Urban and Schwarzenberg~ Berlin-Munich 1963, Volume 14~ page 139.
The polymerization of the monomer mixture is carried out at pres-sures above 800 atmospheres, 4s a rule, pressures of up to 3,000 atmospheres are used, but the polymerization can also be carried out at pressures of up to 8,ooo atmospheres. The polymerization temperature is from 200 to 350C and preferably from 280 to 330Co Ethylene is copolymerized with tert.-butyl acrylate~ tert.-butyl methacrylate or a mixture of both acrylates in the presence of free radical initiators. By free radical polymerization initia-tors are to be understood catalysts which can also be used for the high pressure homopolymeriæation of ethylene. For exampleJ
oxygenJ ad~antageously in amounts of from 10 to 200 molar ppm, based on the ethylene to be polymerizqd, may be used. Peroxides and other compounds which form free radicals may also be used, as well as mixtures of peroxides having different decomposition points, hydroperoxidesJ and mixtures o~ oxygen and peroxides and/or hydro-peroxides. Examples of peroxides and hydroperoxides are tert.-butyl peroxypivalate, di~tert.-butyl peroxide, tert,-butyl hydro-peroxide, tert.-butyl perbenzoate, p-menthane hydroperoxide and dilauroyl peroxide. Compounds such as azoisobutyrodinitrile are
The ethylene employed for the polymerlzation should be at least 98 per cent pure. tert.-Butyl acrylate and tert.-butyl meth-acrylate are commercially available. The ethylene copolymers, which contain~ as copolymerized units, a predominant amount of ethylene, from 1 to 10 per cent by we~ght of acrylic acid and/or methacrylic acid and ~rom 1 to 20 per cent by weight of tert.-butyl acrylate and~or tert.-butyl methacrylate, are manufactured in conventional equipment, eg. autoclaves or tubul~r reactors. It has proved par-ticularly advantageous to carry out the process continuously. Pre-ferably, the polymerization is qarried out in tubular reactors, cf. Ullmanns Encyklopadie der technischen Chemie, 3rd Edition, Urban and Schwarzenberg~ Berlin-Munich 1963, Volume 14~ page 139.
The polymerization of the monomer mixture is carried out at pres-sures above 800 atmospheres, 4s a rule, pressures of up to 3,000 atmospheres are used, but the polymerization can also be carried out at pressures of up to 8,ooo atmospheres. The polymerization temperature is from 200 to 350C and preferably from 280 to 330Co Ethylene is copolymerized with tert.-butyl acrylate~ tert.-butyl methacrylate or a mixture of both acrylates in the presence of free radical initiators. By free radical polymerization initia-tors are to be understood catalysts which can also be used for the high pressure homopolymeriæation of ethylene. For exampleJ
oxygenJ ad~antageously in amounts of from 10 to 200 molar ppm, based on the ethylene to be polymerizqd, may be used. Peroxides and other compounds which form free radicals may also be used, as well as mixtures of peroxides having different decomposition points, hydroperoxidesJ and mixtures o~ oxygen and peroxides and/or hydro-peroxides. Examples of peroxides and hydroperoxides are tert.-butyl peroxypivalate, di~tert.-butyl peroxide, tert,-butyl hydro-peroxide, tert.-butyl perbenzoate, p-menthane hydroperoxide and dilauroyl peroxide. Compounds such as azoisobutyrodinitrile are
-3-~ O.Z. 31,351 a'~o included under free radical polymerization initiators In a special embodiment Or the process according to the in-vention, conventional polymqrization regulators are used. By means of these ~t is possible to vary the melt index of the ethylene co-polymers produced. Examples of suitable regulator~ are hydro~en, ~etoneS, alcohols, ethers and normal and branched hydrocarbons;
propylene, methyl ethyl ketone and propionaldehyde are used pre-ferentially. In general, from 0.2 to 5 mole per cent of the poly-merization regulators, based on the ethylene to be polymerized, are employed.
The copolymerization of the ethylene with tert.-butyl acrylate or tert.-butyl methacrylate can also be carried out in the presence of other compounds whioh are copolymerizable with ethylene. Examples of suitable çomonomers are vlnyl esters derived from saturated carb-oxylic acids of 3 to 8 carbon atoms, other acrylic acid esters and methacrylic acid esters, fumaric acid esters and maleic acid esters.
The polymerization is in general carried out in the absence of a solvent. The small amou~ts of an inert solvent, eg. benzene, petroleum or other inert solvents, in which the polymerization initiators are dissolve~, are negligible compared to the other ma-terials employed. If oxygen is used ~s the polymerization intiator, no solvent whatsaever is necessary.
At the e~d Or the polymerization reactor, the temperature of the reaction mixture is in general above 285C. The reaction mix-ture is then passed into a cooling zone where it is cooled to from 200 to 250C. This step may either be carried out under the pres-sure at which the polymerization is carried out, or after letting down the reaction mixture3 at ~ressures below 500 atmospheres. Im-mediately aftqr the cooling treatment, the reaction mixture is fed ; ~0 into a high pressure product isolation zone in which it ls kept at a temperature of from 200 to 25QC which preferably varies by at most ~ 2C, and where it undergoes partial pyrolysis. This con-verts the copolymerized tert.-butyl acrylate units or tert.-butyl oOZ. 31y351 me~acrylate units partially into acrylic acid units or methacrylic acid units, with elimination of isobutyleneO The temperature of the reaction mixture in the pyrolysis zone pre~erably does not va-ry by more than -~ 2C. If the temperature variation in this zone is greater, the pyrolysis o~ the tert.-butyl acrylate or tert,-bu-tyl methaorylate units becomes uncontrolled and inhomogeneous pro-ducts are obtained. The mean residence time o~ the reaction mix-ture in the pyrolysis zone is in general rrom 2 to 10 minutes. The mean residence time is the time for which the copolymer formed re-mains in the reactor zone in which a pressure below 500 atmospheresand a temperature of from 200 to 250C prevails. The mean residence time is defined by the ratio of the volume of the apparatus to the mean volume of product which has passed through the volume o~ the apparatus per unit tlme. The pressure in the pyrolysis zone is in general from 50 to 500 atmospheres. However~ the pyrolysis can al-so be carried out at lower pressures or under reduced pressure, eg.
at from 1 to 50 mm Hg. According to the inventionl homogeneous co-polymers are obtained, which contain, as copolymerized units9 more ; than 60 per cent by weight of ethylene, from l to 10 per cent by weight of acrylic acid and/or methacrylic acid and ~rom l to 20 per cent by weight of tert,-butyl acrylate and/or tert.-butyl meth-acrylate. The ethylçne copolymers manufactured by the process of the invention are homogeneous and are used~ above allg as hot-melt adhesives, eg. ~or metals, ceramics, paper, textilesg plastics, ; wood, glass and the like. For example, in contrast to polyethylene, the copolymers can easily be colored or printed with most conven-tional dyes. When blended with polyole~ins, the copolymers give mixtures which can also be printed and dyed. Since the ethylene copolymers manufactured according to the invention are homogeneous~
they can easily be converted to thin, homogeneous films which are employed as hot~melt adhesive films. The melt index o~ the ethyl-ene copolymers manufactured according to the invention is from 0.1 to 50, preferab}y from 1 to 20, g/10 min. (determined ac-~ O~Z ~351cord~ to ASTM D 123~-65 T at from 190~ under a load of 2v16 kg)o The Examples which follow illustrate the inventionO The poly-merization apparatus is a tubular reactor as conventional~y employed for continuous high-pressure polymerizationO The ratio of the dia-meter of the reaction tube to its length is 1020,000. The reaction tube is surrounded by a jacketing tube which contains a heat trans fer medium. The reaction tu~e is divided into two zones which can be heated independently of one another, the first zone extending over two-fifth~ of the length of the tube and the second over the remain-ing three-fifths of the length of the reaction tubeO ~t the end of the reaction tube there is a valve which serves both to regulate the pressure in the polymerization space and also to discharge the reaction productl This valve is followed by a ~acketed tube in which the reaction mixture which has left the reaction tube is cooled to a temperature of from 200 to a maximum of 250~o The pressure in this zone is less than 500 atmospheres. At this temperature~ the re action mixture is then passed into a high pressure product isola-tion zone or high pressure separator, in which the pressure is ap-proximately the same as in the preceding jacketed tubeO In this zone, the polymer obtained in the reaction tube is separated from the non-polymerized monomers. The mean residence time of the reaction mix-ture9 obtained from the polymerizationJ after having been cooled to from 200 to 250C~ is from 2 to 10 minutesO ~rom the high pressure product lsolation zone the polymer~ which still contains small amounts of monomer, is passed to a low pressure product separator at pres-sures of less than 10 atmospheres, and from this latter separator the polymer is fed to an extruder. The non-polymerized monomers are recycled to the reactor, via a conventional separator system for re movlng materials which are liquid under normal conditionsO The amount of these components removed from the c~rculation system is only suf-ficient to ensure a stationary state when the reactor is operatlng continuously.
In the Examples, parts are by weightO
-6;
3La~ f~ o zO ~ 51 EXAMPIE, 1 A mixture whioh consists of 10,000 parts of ethylene, 270 parts of tert.-butyl acrylate and 14 molar ppm of` oxygen, based on ethyl-ene, is compressed to 2,200 atmospheres and fed to the reaotor de-scribed above. The heat transfer medium in zones I and II of the re actor jacket is kept at 200C during the polymerizationO As a re-sult of the exothermicity of the reaction" the reaction mixture reaches peak temperatures of 300C in both the reaction zones~ The mean residence time of the reaction mixture in the reactor is 50 seconds.
The polymer is cooled to 250C under a pressure of ;500 at-mospheres and is left under a pressure of 270 atmospheres at 250C
in the high pressure separator which is downstream from the reactor.
The temperature in the high pressure separator is kept constant so that the maximum deviation is -~ 2C. The mean residence time of the ethylene copolymer in the high pressure separator is 10 minutes.
1,850 parts of an ethylene copolymer which contains ~7 per cent by weight of tert.-butyl acrylate and 508 per cent by weight of acrylic acid, as copolymerized units, are obtained. The ethylene copolymer has a melt index (190C/2.16 kg) of 7.1 g~10 mins and a density (ac cording to DIN 53,479/7.2) of 0.927~ g/cm3, and exhibits good ho-mogenelty and gives films having good properties.
EXAMPI~E 2 The procedure described in Example 1 is followed but the poly-merization is carried out under a pressure of 29300 atmospheres~ As a result of the exothermicity of the reaction, the reaction mixture reaches peak temperatures of 315C. The polymer is cooled to 210C
under a pressure of 300 atmospheres and is then transferred direct-ly to the high pressure separator in which it is kept for 8 minutes at a pressure OI 280 atmospheres and at 210C9 with a maximum de-viation of + 2Cc 1,900 parts of an ethylene copolymer containing ~0 7.8 per cent by weight of ter~ -butyl acrylate and ~iOO per cent by weight of acrylic acidj as copolymerized unitsi are obtairled, The 6'~L~f~
OoZo ~1 9351 eth~ene copolymer has a melt index (190C/2016 kg) of 7~4 g/10 mins and a density of 0.9269 g/cm~, and exhibits good homogeneity and gives films having good properties~
The procedure described in Example 2 is ~ollowed but the po-lymer is pyrolyzed at 2~0C lnstead o~ 210Co The temperature of the polymer in the pyrolysis zone is kept constant and deviates by at most + 2C. 1,900 parts of an ethylene copolymer containing 6.6 per cent by wei~ht of tert.-butyl acrylate and 4~1 per cent by weight of acrylic acid are obtainedO The ethylene copolymer has a melt index (190C/2.16 kg) of 8.0 g/10 mins and a density (accord-ing to DIN 53,479/7.2) of 0.9271 g/cm3) and exhibits good homoge-neity and gives films having good properties.
A mixture of 10,000 parts of ethyleneJ 270 parts of tert -` butyl acrylate and 14 molar ppm of oxygen, based on ethylene, ispolymerized by the method described in Example 1~ under a pressure of 2,200 atmospheres. The polymerization conditions are the same as those stated in Example 1. In modification of Example 19 the polymer is not cooled and instead is transferred direct to a pro-duct separator in which it remains for 60 seconds at ~10Co The temperature fluctuates by about +10 CO An ethylene copolymer which is inhomogeneous and unsuitable for the manufacture of thin hot-melt adhesive films is obtained. Various samples of the product whioh were taken show that the composikion varies; egO, from 7.0 to 9.0 per cent by weight of acrylic acid, and a melt index (190C/
2.16 kg) of from 4.5 to 8.8 g/10 mins, are found The copolymerized tert.-butyl acrylate is pyrolyzed completely under the stated conditions.
A mixture whioh consists of 10,000 parts of ethylene and ~00 parts of tert.-butyl acrylate and is compressed to 29~00 a~-~0 mospheres is fed to the reactor desoribed in Example 1, The poly-~6~ oOzO ~1,351 meri ~tion is carried out in the presence of ~0 ppm of oxygen~ Thetemperature o~ the heat transfer medium is 180C in zone I and 200C
in zone II. As a result of the exothermicity of the reaction, the reaction mixture reaches a maximum temperature of 270C in both zones. The residenae time during polymerization is 60 seconds, The reaction mixture is then le~t for 50 seconds ln t}le product sepa-rator at 320 C under a pressure of 280 atmospheres~ 13 900 parts of an ethylene copolymer which contains ~rom 7.5 to 9,6 per cent by weight o~ acrylic acid as copolymerized units are obtainedO The co-polymerized tert.-butyl acrylate is pyrolyzed completely under the above conditions. The ethylene copolymer obtained is very inhomo-geneous and is unsuitable for the manufacture o~ hot-melt adhesive fil~s.
The homogeneity of t~ ethylene copolymersJ referred to in the Examples, was determined on 40/u thick films~ The films were pre-pared by extruding the ethylene copolymer, obtained in the various ExamplesJ at a material temperature of 150C~ The draw off speed is 6.5 m/minute, the ~rost line 250 mm and the blow-up ratio is 1.2.
The extruded tubular film passes through an optical instrument which 1:
;i20 continuously measures inhomogeneities in the film. The measurement covers a 5 cm zone of the lay-flat film which passes through it and which is 23 cm wide. Each inhomogeneity in the film (specks, clots, ~ish-eyesj generates an electrical pulseO The number of pulses, ~ which corresponds to the number of specks, is counted over a period ;~ of measurement of, eg., 400 seconds (corresponding to the scanning of a film area of 4,3 m2). By varying the sensitlvity setting used for the measurement, the inhomogeneities can be divlded into 3 groups, namely I speck sizç from 0.5 to 1 mm II speck size from 1 to 2 mm III speck size greater than 2 mmO
The results are summarized in the TableO
~' , ) ~ o.z. ~ 51 .g U~'~
â ~ ~
H ~ C~J ~1 C~l H ~ o C i . O 11~ ~
. C`l 0 ~3 ~ h p~ E; . ' . ~
ta ~ 8 $
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,~
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~ ~~ o æ rl +l ~1. +1 . I . 1. h . ~ ~ ~.
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a ,,},. O O O , .X h ~ ~ ~1 . +1 +1 ~I c) O a) ~
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P~ O C~ , O O O ~ o ~ )~!1 0 ,~, x ~ o o o ) a~ h ~ ,~
0 +1 ~1 +1 1 1 ~ o ~ :~
' .~ r-l r-l r~ J O Lr~ ~ 1~
~D ~ ~- 0 ;i- ;~'_ ~ ~ O
a, u~
r l r~ - + r-l 1;o o o g) o t~ a) tl~ a ~I rl h r~h rl O O t~
P~ .t~ ~:4t~ p, t~
E E3 ' ~ Ql E3P( ~3 ~ '~ 'x 8 ~a x ~ ~ H O E-l .
,' . ' ..
. :
,_", . , .,,, .. ,, _ ,.. ...
propylene, methyl ethyl ketone and propionaldehyde are used pre-ferentially. In general, from 0.2 to 5 mole per cent of the poly-merization regulators, based on the ethylene to be polymerized, are employed.
The copolymerization of the ethylene with tert.-butyl acrylate or tert.-butyl methacrylate can also be carried out in the presence of other compounds whioh are copolymerizable with ethylene. Examples of suitable çomonomers are vlnyl esters derived from saturated carb-oxylic acids of 3 to 8 carbon atoms, other acrylic acid esters and methacrylic acid esters, fumaric acid esters and maleic acid esters.
The polymerization is in general carried out in the absence of a solvent. The small amou~ts of an inert solvent, eg. benzene, petroleum or other inert solvents, in which the polymerization initiators are dissolve~, are negligible compared to the other ma-terials employed. If oxygen is used ~s the polymerization intiator, no solvent whatsaever is necessary.
At the e~d Or the polymerization reactor, the temperature of the reaction mixture is in general above 285C. The reaction mix-ture is then passed into a cooling zone where it is cooled to from 200 to 250C. This step may either be carried out under the pres-sure at which the polymerization is carried out, or after letting down the reaction mixture3 at ~ressures below 500 atmospheres. Im-mediately aftqr the cooling treatment, the reaction mixture is fed ; ~0 into a high pressure product isolation zone in which it ls kept at a temperature of from 200 to 25QC which preferably varies by at most ~ 2C, and where it undergoes partial pyrolysis. This con-verts the copolymerized tert.-butyl acrylate units or tert.-butyl oOZ. 31y351 me~acrylate units partially into acrylic acid units or methacrylic acid units, with elimination of isobutyleneO The temperature of the reaction mixture in the pyrolysis zone pre~erably does not va-ry by more than -~ 2C. If the temperature variation in this zone is greater, the pyrolysis o~ the tert.-butyl acrylate or tert,-bu-tyl methaorylate units becomes uncontrolled and inhomogeneous pro-ducts are obtained. The mean residence time o~ the reaction mix-ture in the pyrolysis zone is in general rrom 2 to 10 minutes. The mean residence time is the time for which the copolymer formed re-mains in the reactor zone in which a pressure below 500 atmospheresand a temperature of from 200 to 250C prevails. The mean residence time is defined by the ratio of the volume of the apparatus to the mean volume of product which has passed through the volume o~ the apparatus per unit tlme. The pressure in the pyrolysis zone is in general from 50 to 500 atmospheres. However~ the pyrolysis can al-so be carried out at lower pressures or under reduced pressure, eg.
at from 1 to 50 mm Hg. According to the inventionl homogeneous co-polymers are obtained, which contain, as copolymerized units9 more ; than 60 per cent by weight of ethylene, from l to 10 per cent by weight of acrylic acid and/or methacrylic acid and ~rom l to 20 per cent by weight of tert,-butyl acrylate and/or tert.-butyl meth-acrylate. The ethylçne copolymers manufactured by the process of the invention are homogeneous and are used~ above allg as hot-melt adhesives, eg. ~or metals, ceramics, paper, textilesg plastics, ; wood, glass and the like. For example, in contrast to polyethylene, the copolymers can easily be colored or printed with most conven-tional dyes. When blended with polyole~ins, the copolymers give mixtures which can also be printed and dyed. Since the ethylene copolymers manufactured according to the invention are homogeneous~
they can easily be converted to thin, homogeneous films which are employed as hot~melt adhesive films. The melt index o~ the ethyl-ene copolymers manufactured according to the invention is from 0.1 to 50, preferab}y from 1 to 20, g/10 min. (determined ac-~ O~Z ~351cord~ to ASTM D 123~-65 T at from 190~ under a load of 2v16 kg)o The Examples which follow illustrate the inventionO The poly-merization apparatus is a tubular reactor as conventional~y employed for continuous high-pressure polymerizationO The ratio of the dia-meter of the reaction tube to its length is 1020,000. The reaction tube is surrounded by a jacketing tube which contains a heat trans fer medium. The reaction tu~e is divided into two zones which can be heated independently of one another, the first zone extending over two-fifth~ of the length of the tube and the second over the remain-ing three-fifths of the length of the reaction tubeO ~t the end of the reaction tube there is a valve which serves both to regulate the pressure in the polymerization space and also to discharge the reaction productl This valve is followed by a ~acketed tube in which the reaction mixture which has left the reaction tube is cooled to a temperature of from 200 to a maximum of 250~o The pressure in this zone is less than 500 atmospheres. At this temperature~ the re action mixture is then passed into a high pressure product isola-tion zone or high pressure separator, in which the pressure is ap-proximately the same as in the preceding jacketed tubeO In this zone, the polymer obtained in the reaction tube is separated from the non-polymerized monomers. The mean residence time of the reaction mix-ture9 obtained from the polymerizationJ after having been cooled to from 200 to 250C~ is from 2 to 10 minutesO ~rom the high pressure product lsolation zone the polymer~ which still contains small amounts of monomer, is passed to a low pressure product separator at pres-sures of less than 10 atmospheres, and from this latter separator the polymer is fed to an extruder. The non-polymerized monomers are recycled to the reactor, via a conventional separator system for re movlng materials which are liquid under normal conditionsO The amount of these components removed from the c~rculation system is only suf-ficient to ensure a stationary state when the reactor is operatlng continuously.
In the Examples, parts are by weightO
-6;
3La~ f~ o zO ~ 51 EXAMPIE, 1 A mixture whioh consists of 10,000 parts of ethylene, 270 parts of tert.-butyl acrylate and 14 molar ppm of` oxygen, based on ethyl-ene, is compressed to 2,200 atmospheres and fed to the reaotor de-scribed above. The heat transfer medium in zones I and II of the re actor jacket is kept at 200C during the polymerizationO As a re-sult of the exothermicity of the reaction" the reaction mixture reaches peak temperatures of 300C in both the reaction zones~ The mean residence time of the reaction mixture in the reactor is 50 seconds.
The polymer is cooled to 250C under a pressure of ;500 at-mospheres and is left under a pressure of 270 atmospheres at 250C
in the high pressure separator which is downstream from the reactor.
The temperature in the high pressure separator is kept constant so that the maximum deviation is -~ 2C. The mean residence time of the ethylene copolymer in the high pressure separator is 10 minutes.
1,850 parts of an ethylene copolymer which contains ~7 per cent by weight of tert.-butyl acrylate and 508 per cent by weight of acrylic acid, as copolymerized units, are obtained. The ethylene copolymer has a melt index (190C/2.16 kg) of 7.1 g~10 mins and a density (ac cording to DIN 53,479/7.2) of 0.927~ g/cm3, and exhibits good ho-mogenelty and gives films having good properties.
EXAMPI~E 2 The procedure described in Example 1 is followed but the poly-merization is carried out under a pressure of 29300 atmospheres~ As a result of the exothermicity of the reaction, the reaction mixture reaches peak temperatures of 315C. The polymer is cooled to 210C
under a pressure of 300 atmospheres and is then transferred direct-ly to the high pressure separator in which it is kept for 8 minutes at a pressure OI 280 atmospheres and at 210C9 with a maximum de-viation of + 2Cc 1,900 parts of an ethylene copolymer containing ~0 7.8 per cent by weight of ter~ -butyl acrylate and ~iOO per cent by weight of acrylic acidj as copolymerized unitsi are obtairled, The 6'~L~f~
OoZo ~1 9351 eth~ene copolymer has a melt index (190C/2016 kg) of 7~4 g/10 mins and a density of 0.9269 g/cm~, and exhibits good homogeneity and gives films having good properties~
The procedure described in Example 2 is ~ollowed but the po-lymer is pyrolyzed at 2~0C lnstead o~ 210Co The temperature of the polymer in the pyrolysis zone is kept constant and deviates by at most + 2C. 1,900 parts of an ethylene copolymer containing 6.6 per cent by wei~ht of tert.-butyl acrylate and 4~1 per cent by weight of acrylic acid are obtainedO The ethylene copolymer has a melt index (190C/2.16 kg) of 8.0 g/10 mins and a density (accord-ing to DIN 53,479/7.2) of 0.9271 g/cm3) and exhibits good homoge-neity and gives films having good properties.
A mixture of 10,000 parts of ethyleneJ 270 parts of tert -` butyl acrylate and 14 molar ppm of oxygen, based on ethylene, ispolymerized by the method described in Example 1~ under a pressure of 2,200 atmospheres. The polymerization conditions are the same as those stated in Example 1. In modification of Example 19 the polymer is not cooled and instead is transferred direct to a pro-duct separator in which it remains for 60 seconds at ~10Co The temperature fluctuates by about +10 CO An ethylene copolymer which is inhomogeneous and unsuitable for the manufacture of thin hot-melt adhesive films is obtained. Various samples of the product whioh were taken show that the composikion varies; egO, from 7.0 to 9.0 per cent by weight of acrylic acid, and a melt index (190C/
2.16 kg) of from 4.5 to 8.8 g/10 mins, are found The copolymerized tert.-butyl acrylate is pyrolyzed completely under the stated conditions.
A mixture whioh consists of 10,000 parts of ethylene and ~00 parts of tert.-butyl acrylate and is compressed to 29~00 a~-~0 mospheres is fed to the reactor desoribed in Example 1, The poly-~6~ oOzO ~1,351 meri ~tion is carried out in the presence of ~0 ppm of oxygen~ Thetemperature o~ the heat transfer medium is 180C in zone I and 200C
in zone II. As a result of the exothermicity of the reaction, the reaction mixture reaches a maximum temperature of 270C in both zones. The residenae time during polymerization is 60 seconds, The reaction mixture is then le~t for 50 seconds ln t}le product sepa-rator at 320 C under a pressure of 280 atmospheres~ 13 900 parts of an ethylene copolymer which contains ~rom 7.5 to 9,6 per cent by weight o~ acrylic acid as copolymerized units are obtainedO The co-polymerized tert.-butyl acrylate is pyrolyzed completely under the above conditions. The ethylene copolymer obtained is very inhomo-geneous and is unsuitable for the manufacture o~ hot-melt adhesive fil~s.
The homogeneity of t~ ethylene copolymersJ referred to in the Examples, was determined on 40/u thick films~ The films were pre-pared by extruding the ethylene copolymer, obtained in the various ExamplesJ at a material temperature of 150C~ The draw off speed is 6.5 m/minute, the ~rost line 250 mm and the blow-up ratio is 1.2.
The extruded tubular film passes through an optical instrument which 1:
;i20 continuously measures inhomogeneities in the film. The measurement covers a 5 cm zone of the lay-flat film which passes through it and which is 23 cm wide. Each inhomogeneity in the film (specks, clots, ~ish-eyesj generates an electrical pulseO The number of pulses, ~ which corresponds to the number of specks, is counted over a period ;~ of measurement of, eg., 400 seconds (corresponding to the scanning of a film area of 4,3 m2). By varying the sensitlvity setting used for the measurement, the inhomogeneities can be divlded into 3 groups, namely I speck sizç from 0.5 to 1 mm II speck size from 1 to 2 mm III speck size greater than 2 mmO
The results are summarized in the TableO
~' , ) ~ o.z. ~ 51 .g U~'~
â ~ ~
H ~ C~J ~1 C~l H ~ o C i . O 11~ ~
. C`l 0 ~3 ~ h p~ E; . ' . ~
ta ~ 8 $
H ~ s ~ r~l ~--1 'd h, ` ' r-t . ~ ~ ~ ho ~1 ' h _, t~
,~
~ ~ 'O 'O '~. O ' O ~ O
.~; ~ ;~ ~ ~J g g ~ h ~
H I . ; .. I ~ t) aD
O . o t~
. . .
;~ . . . ~ r 3 h h o q~ ~ q~ ~ ~ ~ h h '~
E~ ~ O ~ O ~ O O, O
. o ~ ~ ~ o ~ o o o h o ':' ~ )~ ~) O
1~ ~ ",,, o o o a~ o~
~ ~~ o æ rl +l ~1. +1 . I . 1. h . ~ ~ ~.
nd`-- 0 o ~1 ~ . m o ~ ~
,, ,~. ~ ~ . ~ ' '. ~ O.
a ,,},. O O O , .X h ~ ~ ~1 . +1 +1 ~I c) O a) ~
h o æ a~ r~ .D ~3 0 s J ~ ~5) . , a~ q~, a) rl ~1 . ~ h ' . ' ~ C~ ,1 0 u~ a~ ~3 Q) - ~ 3 c~ n. ,~ . ~ h a o c~ l ~ Ul h ~ .-. . , . ~
P~ O C~ , O O O ~ o ~ )~!1 0 ,~, x ~ o o o ) a~ h ~ ,~
0 +1 ~1 +1 1 1 ~ o ~ :~
' .~ r-l r-l r~ J O Lr~ ~ 1~
~D ~ ~- 0 ;i- ;~'_ ~ ~ O
a, u~
r l r~ - + r-l 1;o o o g) o t~ a) tl~ a ~I rl h r~h rl O O t~
P~ .t~ ~:4t~ p, t~
E E3 ' ~ Ql E3P( ~3 ~ '~ 'x 8 ~a x ~ ~ H O E-l .
,' . ' ..
. :
,_", . , .,,, .. ,, _ ,.. ...
Claims (2)
1. A process for the manufacture of copolymers of ethylene which contain, as copolymerized units, more than 60 per cent by weight of ethylene, from 1 to 20 per cent by weight of tert.-butyl acrylate and from 1 to 10 per cent by weight of acrylic acid, by copolymerization of ethylene and tert.-butyl acrylate at from 200 to 350°C at pressures above 800 atomspheres, wherein the reaction mixture obtained after the polymerization is passed into a zone which is at a pressure below 500 atmospheres and at from 200 to 250°C, the mean residence time of the reaction mixture in this zone and in the high pressure product isolation zone immediately down-strean therefrom being from 2 to 10 minutes.
2. A process as claimed in claim 1, wherein the temperature of the reaction mixture in the high pressure product isolation zone is from 200 to 250°C and varies by at most + 2°C.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE2524274A DE2524274B2 (en) | 1975-05-31 | 1975-05-31 | Process for the production of copolymers of ethylene |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1061942A true CA1061942A (en) | 1979-09-04 |
Family
ID=5947971
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA252,152A Expired CA1061942A (en) | 1975-05-31 | 1976-05-10 | Manufacture of copolymers of ethylene |
Country Status (8)
| Country | Link |
|---|---|
| JP (1) | JPS6011725B2 (en) |
| AT (1) | AT343353B (en) |
| BE (1) | BE842394A (en) |
| CA (1) | CA1061942A (en) |
| DE (1) | DE2524274B2 (en) |
| FR (1) | FR2313406A1 (en) |
| GB (1) | GB1538894A (en) |
| NL (1) | NL7605786A (en) |
Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4599392A (en) * | 1983-06-13 | 1986-07-08 | The Dow Chemical Company | Interpolymers of ethylene and unsaturated carboxylic acids |
| SE453622B (en) * | 1983-12-08 | 1988-02-15 | Asea Ab | SEMICONDUCTOR COMPONENT FOR GENERATING OPTICAL RADIATION |
| DE3404743A1 (en) * | 1984-02-10 | 1985-08-14 | Basf Ag, 6700 Ludwigshafen | COPOLYMERISATES OF ETHYLENE WITH COMONOMERS CONTAINING CARBOXYL GROUPS |
| JPS61127709A (en) * | 1984-11-27 | 1986-06-16 | Sumitomo Chem Co Ltd | Production of ethylene copolymer |
| US5945083A (en) * | 1995-03-10 | 1999-08-31 | Kawasaki Jukogyo Kabushiki Kaisha | Process for producing iron carbide and equipment therefor |
| DE10008931A1 (en) | 2000-02-25 | 2001-08-30 | Basf Ag | Process for the preparation of emulsifiable ethylene polymers |
| JP2008050148A (en) * | 2006-08-28 | 2008-03-06 | Kansai Kanaami Kk | Conveyor belt and conveying device |
| CN101679565B (en) * | 2007-03-30 | 2012-05-23 | Lg化学株式会社 | Copolymer comprising alkene, acrylate and unsaturated organic acid, and method for preparing the same |
| EP3181599A1 (en) * | 2015-12-18 | 2017-06-21 | Borealis AG | Novel process for producing a polar ethylene copolymer with low melt flow rate |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| BE591916A (en) * | 1959-06-23 | |||
| US3132120A (en) * | 1961-02-03 | 1964-05-05 | Du Pont | Method for the preparation of ethylene copolymers |
| DE1720335C3 (en) * | 1967-12-21 | 1985-01-03 | Basf Ag, 6700 Ludwigshafen | Process for the production of copolymers of ethylene |
| DE1770777A1 (en) * | 1968-07-03 | 1971-12-02 | Basf Ag | Process for the production of waxy copolymers of ethylene |
| DE2119047C3 (en) * | 1971-04-20 | 1978-09-14 | Basf Ag, 6700 Ludwigshafen | Process for the production of copolymers of ethylene |
-
1975
- 1975-05-31 DE DE2524274A patent/DE2524274B2/en active Granted
-
1976
- 1976-05-10 CA CA252,152A patent/CA1061942A/en not_active Expired
- 1976-05-21 JP JP51058003A patent/JPS6011725B2/en not_active Expired
- 1976-05-27 GB GB22031/76A patent/GB1538894A/en not_active Expired
- 1976-05-28 FR FR7616211A patent/FR2313406A1/en active Granted
- 1976-05-28 NL NL7605786A patent/NL7605786A/en not_active Application Discontinuation
- 1976-05-28 AT AT393676A patent/AT343353B/en not_active IP Right Cessation
- 1976-05-31 BE BE167479A patent/BE842394A/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| GB1538894A (en) | 1979-01-24 |
| DE2524274C3 (en) | 1987-09-10 |
| DE2524274B2 (en) | 1980-03-13 |
| ATA393676A (en) | 1977-09-15 |
| FR2313406A1 (en) | 1976-12-31 |
| NL7605786A (en) | 1976-12-02 |
| JPS6011725B2 (en) | 1985-03-27 |
| DE2524274A1 (en) | 1976-12-09 |
| JPS52886A (en) | 1977-01-06 |
| BE842394A (en) | 1976-12-01 |
| FR2313406B1 (en) | 1980-12-19 |
| AT343353B (en) | 1978-05-26 |
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