FR2464969A1 - PROCESS FOR PREPARING COPOLYMERS OF ETHYLENE - Google Patents

Abstract

PROCESS FOR PREPARING ETHYLENE COPOLYMERS CONTAINING ALKENOIC ACIDS BY POLYMERIZATION OF MIXTURES OF CORRESPONDING MONOMERS CONTAINING ESTERS OF ALKENOIC ACIDS. AFTER FORMATION OF A COPOLYMER INTO PARTICLES OF SIZE 0.1 TO 8MM, WE SUSPEND THESE PARTICLES IN A KETONE, AN ALCOHOL OR AN ESTER RESPECTIVELY RESPONDING TO THE GENERAL FORMULAS: (CF DRAWING IN BOPI) IN WHICH R AND R, IDENTICAL OR DIFFERENT, EACH REPRESENT A C1-C6 ALKYL GROUP, AND WE SUBJECT TO SCISION AT TEMPERATURES OF 40 TO 75C IN THE PRESENCE OF ACID CATALYSTS.

Description

The present invention relates to a process for preparing copolymers of

  ethylene which contain (1) at least 50% by weight of ethylene; (2) from 0 to 25% by weight of C 3 -C 12 alkenoic acid esters and C 3 -C 8 secondary alcohols and / or tertiary C 4 -C 8 alcohols,

  (3) from 0 to 25% by weight of a viryl ester of a carboxylic acid

  C 1 -C 6 saturated monobasic aliphatic ring; (4) from 1 to 25% by weight of C 3 -C 12 alkenic acids; and

  (5) minor proportions of other customary monomers copoly-

Merisable with ethylene.

  The preparation of copolymers containing alkenotic acids is known. Thus, mixtures of ethylene, alkenoic acids and other monomers, at high pressure and high temperature, can be converted by radical initiators (see, for example, patent applications of the Federal Republic of Germany). Published in DOS 2,400,978 and 1,669,685). A disadvantage of this process is the corrosive effect of the acids

  free alcohols on the switchgear parts under the conditions

  observed. Highly colored polymers are then obtained.

  To avoid these difficulties and according to other

  known compounds are used as monomers in the poly-

  esterification of the esters of the alkenotic acids, and the alcohol radical is then removed. A way to break the bond between alcohol

  and the acid is to hydrolyze the ester in an acidic or alkaline medium.

  For this purpose, the polymer is treated with acids or with alkali metal hydrocides. The cleavage by hydrolysis of the ester groups is

  performed in solution and supposes long operating times.

  It is then necessary to isolate the reaction product with the aid of a precipitating agent. These long and painful operations make the process only of limited interest from an industrial point of view. Another method is to cut the esters by pyrolysis (see, for example, U.S. Patent No. 3,132,120 and Federal Republic of Germany Patent Applications under DOS).

  1,720,335 and 2,119,047). This process requires the observation of

  relatively high eratures. On the other hand, there occur side reactions consisting of other undesirable scission reactions. Moreover, there may be reactions from

  intermolecular condensation leading to products that pre-

  have a marked feeling of defects called "fish eyes".

  Finally, the homogeneity of products prepared thermally

  also leaves something to be desired. This defect manifests itself

  especially disadvantageous when the polymers are intended for

  be used as fusible adhesives. -

  There is therefore a need for a process for preparing copolymers of ethylene containing

  alkenotics, which are homogeneous, uncrosslinked and unstained.

  Other purposes and advantages of the invention are

  will read the description below.

  According to the invention, these objects and advantages have been achieved in a process for the preparation of ethylene copolymers containing more than 50% by weight of ethylene, from 0 to 25% by weight of alkenotic acid esters in C 3 -C 12 and secondary alcohols C 3 -C 8 and / or tertiary alcohols C 4 -C 8 O

  25% by weight of a vinyl ester of a carboxylic acid

  C 1 -C 6 saturated monobasic phage, from 1 to 25% by weight of C 3 -C 12 alkenoic acids and, if appropriate, minor proportions

  other customary monomers copolymerizable with ethylene, by poly-

  merification of monomer mixtures which, as such, consist of at least 50% by weight of ethylene, 2 to 50% by weight of C 3 -C 12 alkenoic acid esters and C 3 -C 3 secondary alcohols. C 8 and / or C 4 -C 8 tertiary alcohols, 8 to 30% by weight of a vinyl ester of a C 1 -C 6 saturated monobasic aliphatic carboxylic acid, up to 3% by weight of C 3 -C 12 alkenotec acids and minor proportions of other copolymerizable monomers

  with ethylene, at pressures of 100 to 8000 bar and

  from 150 to 3501C, in the presence of catalytic amounts of

  radical ductors. The novel process is characterized by suspending 1 part by weight of copolymer particles having a size of 0.1 to 8 mm, preferably 1 to 5 mm, in 1 to 12 parts by weight of a ketone, an alcohol or an ester of the respective general formulas: "I RC-R ', R-OH and R-COOR' in which R and R ', having identical or different meanings, each representing an alkyl group straight or branched C 1 -C 6, and the alkenoic acid esters contained in the polymer are cleaved at temperatures of 40 to 75 C in the presence of

acid catalysts.

  Against all expectations, the process according to the invention gives not only homogeneous and non-colored products, but also avoids the incidents that may occur as a result of deposits of alkenic acids, sticky, in reactors and

ways of installation.

  The ethylene used as starting material is at the

  the usual purity of at least 99.9% for the poly-

  merization. Among the esters of C 3 -C 12 alkenoic acids and of secondary and / or tertiary alcohols, mention may be made, for example, of tert-butyl acrylate, tert-butyl methacrylate, tert-butyl crotonate and the like. .-butyl, isopropyl acrylate, methacrylate

  isopropyl, di-tert.-butyl maleate and di-tertiary fumarate.

  butyl. We obtained particularly satisfactory results

  with the esters of acrylic or methacrylic acid and of

  butanol, tert.-butanol and tert.-amyl alcohol. Among the suitable vinyl esters, in addition to vinyl acetate, which is the preferred ester, mention may be made of vinyl esters of saturated C 1 -C 6 monobasic carboxylic acids and, for example, vinyl formate, propionate of vinyl and butyrate

of vinyl.

  The usual monomers copolymerizable with ethylene which may be further contained in the polymers according to the invention are, for example, C 3 -C 8 alkenes,

  C 3 -C 12 alkenotic acids, vinyl esters and alkenyl

4.

  vinyl ethers, alkenyl ethers, vinyl alcohols,

  and alkenyl, N-vinyl and N-alkenyl compounds

  such as N-vinylpyrrolidone, N-vinylcarbazole, N-vinylcapro-

  lactam, acrylamides and methacrylamides, acrylonitriles and methacrylonitriles, alkenyl halides such as vinyl fluoride and vinylidene fluoride, vinyl and alkenyl ketones, vinyl and alkenyl sulfones and sulfonates. In addition to the ethylenically unsaturated compounds, it is also possible to copolymerize other copolymerizable substances such as carbon monoxide and

sulfur dioxide.

  The preparation of the copolymers of ethylene con-

  containing esters of alkenotic acids and which are cleaved

  According to the invention, the copolymers containing alkenoic acids are produced in a manner known per se by reacting the monomers at pressures of 100 to 8000 bar and at temperatures of 110 to 350 ° C., in an autoclave or in tubular reactors. (see Ullmanns Encyclopudie der technischen Chemie,

  3rd edition, (1963), volume 14, page 139). The method is preferably

  It is used continuously, and the fractions of the monomers which are not converted are recycled. The reaction is carried out in the presence of catalytic amounts of radical initiators, for example oxygen, in amounts of 2 to 250 ppm molar, relative to the ethylene to be polymerized. In addition to oxygen, one can

  also use peroxides as inducers

  tert.-butyl benzoate, dilauroyl peroxide, ditert-butyl peroxide or azobutyrodinitrile in amounts of 2 to 200 ppm molar, based on ethylene. The polymerization is advantageously carried out in the presence of moderators such as aliphatic alcohols and carbonyl compounds, saturated hydrocarbons

  and unsaturated or chlorinated hydrocarbons and hydrogen.

  At polymerization, the polymers are obtained at

  the particle size of 0.1 to 8 mm required for the treatment

  later by catalytic scission, so that this avoids

  additional operations such as grinding operations.

  A defining characteristic of the process according to the invention resides in the suspension of the original granules in certain organic liquids which diffuse inside the granules and, consequently, also transport the catalyst in the dissolved state. Usually, 1 to 12 parts are used in

  weight, preferably from 2 to 6 parts by weight of auxiliary products.

  suspending agents per part by weight of the copolymer. Among the auxiliary products of organic suspension are ketones, alcohols or esters. These products can be used in pure form or in the mixing state. The important thing is that the auxiliary product

  suspension dissolves the catalyst but not the copolymer at the temperatures

  less than the melting range of the starting material.

  Among the suspension auxiliaries, ketones, alcohols and esters corresponding to the respective general formulas: ## STR1 ## in which R represents a straight or branched C 1 -C 6 alkyl group and R 'a straight or branched C 1 -C 6 alkyl group, have

  particularly satisfactory results and, in particular,

  acetone, methyl ethyl ketone, methyl isobutyl ketone, propanol, isopropanol, butanol, isobutanol, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, isobutyl acetate and mixtures thereof. As catalysts for the cleavage of the alkenotic acid ester contained in the polymer, acidic compounds are used

  and, for example, sulfuric acid or p-toluenesulfonic acid.

  The catalyst can be used in theoretical amount, in excess or in defect, with respect to the copolymerized alkenoic acid ester. Depending on the amount of catalyst, it is possible to regulate at a desired degree of scission. When the excess catalyst is used, the alkenoic acid esters are split almost quantitatively,

  whereas if we use the theoretical quantity or a defect of cata-

  lyser, reaction products are obtained which still contain

  greater or lesser proportions of esters of alkenoic acids.

  The cleavage of the alkenoic acid esters is carried out at temperatures of 40 to 750 ° C. If operating at temperatures below the melting range of the polymer, the granule particles remain intact and their size is substantially unaltered. When speaking of a temperature below the melting range of the polymer, this means a temperature at which the granular particles swell.

  but do not dissolve. This temperature is in a

  from about 5 to 10C below the temperature at which

  the melting phenomenon is triggered.

  To influence the degree of cleavage, regardless of the amount of catalyst added, the operating time can also be used. The latter, depending on the operating temperature, the size of the granules and the amount of copolymerized alkenoic acid esters, is from 30 minutes to 10 hours, in particular from 30 minutes to 5 hours, and preferably from 2 minutes to 3 hours. 4 hrs. Low operating temperatures, strong particle sizes and. the

  high proportions of alkenic acid esters require, for

  come to the same degree of split, longer operating times

  that in the case of high operating temperatures, small

  particle sizes and small proportions of alkenotic acid esters.

  In practice, the split is achieved by

  In a simple way, the polymer is suspended in the ketone, alcohol or ester. The mixture is heated with stirring to the desired temperature, the cleavage catalyst is added and allowed to react.

  until the desired degree of splitting has been achieved.

  The polymers according to the invention find

  plications as glues and, after grinding, as products

coating.

  Supports suitable for gluing or coating

  The copolymers according to the invention are based on ceramic materials, glass, wood or synthetic resins, provided that they resist the thermal stress necessary to melt the synthetic resin powder. The surface of the objects to be coated is advantageously freed before coating

2A64969

  impurities, oils or other impurities, eg oxide layers, solvent cleaning or mechanical cleaning. To further improve the adhesion of the synthetic resin layer on the support, the surface of the latter can be treated by sandblasting, brushing or pickling. However, in many cases, and taking into account the excellent adhesion of the copolymers used according to the invention, such pretreatment is not necessary. Unlike many other synthetic resin powders used for the same purpose,

  for example polyethylene, polyvinyl chloride, acetonitrile

  cellulose butyrate, adhesion of copolymers of ethylene

  containing an alkenotic acid on most materials is sufficient

  It is good that, when submitting test pieces to the tear test, it is not the bonding line that yields but the coating itself which is destroyed. As a result, we can avoid

  the use of a special bonding agent.

  The following examples illustrate the invention without limiting it; in these examples, the indications of parts

  and% are by weight unless otherwise indicated. In these examples

  abbreviations, the meaning of which is in-

hereinafter:

  E ethylene. VAC vinyl acetate.

  t-BA tert-butyl acrylate. MEK methyl ethyl ketone.

  AS acrylic acid. MiBK methyl isobutyl ketone.

EXAMPLE 1

  In a 2 l flask equipped with a stirrer, a reflux condenser and a contact thermometer, 400 g of granules of a copolymer E / t-BA / VAC (composition: 16.8%) are placed. t-BA, 2.77, VAC), m.p. (1900C / 2 kg): 24 and 1.6 L MEK. We add in two portions: 60% immediately, 40% after 3 hours of

  reaction at 66-68 ° C, three times the theoretical amount of sulfuric acid.

  concentrated fur (78 g = 43 ml) relative to the amount of t-BA contained in the ternary copolymer. After a total reaction time of 6 hours, the granules are filtered off and extracted for 2 hours at room temperature.

  reaction temperature with MEK and dried at 60 ° C. under vacuum.

  355 g of colorless granules containing 9.3% AS, 0.4% tBA and 2.7% VAC are obtained; the melt index (190 C / 2kg) is 3.5 g / 10 min.

EXAMPLE 2

  In a flask equipped with a stirrer, a reflux condenser and a contact thermometer, 400 g of granules of a ternary copolymer E / t-BA / AS (composition: 1658% of t-BA) are placed. , 2.7 AS), melt index (190 C / 2 kg): 170 g / 10 min, 1.6 L MEK and 28 ml (51.5 g) concentrated sulfuric acid (twice the equivalent quantity in relation to the quantity of t-BA contained

  in the polymer). After 6 hours of reaction at 65 ° C., the

  are extracted, the MEK is extracted at the reaction temperature and

  then dried at 60 ° C under vacuum. 350 g of unconcentrated granules are obtained.

  lores containing 11.4% AS, 1.4% t-BA, melt index (190 C / 2 Kg): 30 g / 10 min.

EXAMPLE 3

  In a 2 liter flask equipped with a stirrer, a reflux condenser and a contact thermometer, 400 g of granules of a copolymer E / t-BA / VAC (composition: 19% by weight) are placed in a flask. BA,

  3.2% VAC), melt index (190 C / 2 Kg): 100 and 1.20 Kg MEK.

  At the reaction temperature of 68 ° C. and over 4 hours, 14.5 g of concentrated sulfuric acid dissolved in 100 ml of MEK are added dropwise, ie half the amount equivalent to the amount of copolymerized t-BA. . After a further 4 hours of reaction, the procedure is as described in Example 1. 365 g of colorless, partially split granules containing 6.7% AS, 6.9% t-BA and 3.1% are obtained. of VAC, melt index (190 C / 2 kg): 42 g / 10 min.

EXAMPLE 4

  In a 2 l flask equipped with a stirrer, a reflux condenser and a contact thermometer, 400 g of granules of a ternary copolymer E / t-BA / AS (composition: 16.8 %

26 64969

  t-BA, 1.4% / AS), m.p. (190 C / 2 Kg): 35 g / 10 min, and 1.600 ml MEK. In two portions, 70% is added immediately, after 3 hours of reaction at 60 ° C., three times the theoretical amount of concentrated sulfuric acid (78 g, ie 43 ml), relative to the amount of t-BA contained in the reaction mixture. ternary copolymer. After a further 3 hours of reaction at 60 ° C., the granules are filtered off, extracted at reflux temperature with a solution of 9 parts of MEK and 1 part of acetone and dried at 60 ° C. under vacuum. 370 g of colorless granules containing 5.7% of AS and 9.2% of t-BA are obtained, melt index (190 C / 2 kg): 15 g / 10 min.

EXAMPLE 5

  In a 2 l flask equipped with a stirrer, a reflux condenser and a contact thermometer, 200 g of granules of a copolymer E / t-BA / VAC (composition: 19% by weight) are placed in a flask. -BA, 3.3% VAC), melt index (190 C / 2 kg): 110 g / 10 min, and

1.200 g of MEK.

  At 68 ° C., the reaction mixture is continuously added over 4 hours.

  g of toluene-4-sulphonic acid monohydrate, ie 1/3 of the amount

  equivalent to the amount of copolymerized t-BA, dissolved in 200 ml of 85% formic acid. After a further reaction time of 4 hours at 68 ° C., the reaction is terminated in the usual manner. 176 g of colorless granules containing 9.7% AS, 1.7% t-BA and 3.2% VAC are obtained. The melt index (190 C / 2 kg) is 26 g / 10 min.

EXAMPLE 6

  In a 2 l flask equipped with a stirrer, a reflux condenser and a contact thermometer, 400 g of granules of a ternary copolymer E / t-BA / AS (composition: 16.4 % t-BA, 3.0% AS), melt index (190 C / 2 kg): 3.2 g / 10 min and 1.600 ml MEK. It is added in two portions: 70% immediately, 30% after 2 hours of reaction at 68 C, three times the theoretical amount

  concentrated sulfuric acid (78 g = 43 ml) compared to the qua

  t-BA content contained in the ternary copolymer. After a further 2 hours of reaction at 68 ° C., the product is filtered off, extracted with MEK and dried at 60 ° C. under vacuum. 368 g of colorless granules containing 12.1% of AS and 0.2% of t-BA are obtained, melt index (190 C / 2 kg): 0.4 g / 10 min.

EXAMPLE 7

  In a 2 liter flask equipped with a stirrer, a reflux condenser and a contact thermometer, 400 g of granules of a copolymer E / t-BA / VAC (composition: 9.5%) are placed. t-BA, 4.5% VAC), m.p. (190 C / 2 Kg): 23 g / 10 min, and 1.600 ml MiBK. The tertiary quantity of concentrated sulfuric acid is added dropwise continuously over 4 hours at 64 ° C.

  (44 g) relative to the amount of t-BA fixed in the copolymer.

  After a further 2 hours of reaction at 64 ° C., the granules are filtered off, extracted with MEK and dried at 60 ° C. under vacuum. 370 g of colorless granules containing 5.1% of AS, 0.4% of t-BA and 4.4% of VAC are obtained, melt index (190 C / 2 kg): 3 g / 10 min.

EXAMPLE 8

  In a 2 l flask equipped with a stirrer, a reflux condenser and a contact thermometer, 400 g of granules of a ternary copolymer E / t-BA / VAC (composition: 19.8 % t-BA, 2.9% VAC), melt index (190 C / 2 kg): 140 g / 10 min and 1,600 ml of isobutyl acetate. It is added in two portions: 60%

  40% after 2 hours of reaction at 65 ° C, twice the amount

  theory of concentrated sulfuric acid (61 g) relative to the amount of t-BA contained in the ternary polymer. After a further 2 hours of reaction at 65 ° C., the suspension medium is separated, washed 4 times for 30 minutes with 1 liter of acetone at 50 ° C. each time and then dried at 600 ° C. 354 g of colorless granules are obtained

  containing 9.9% AS, 1.6% t-BA and 2.9% VAC, fu-

(190 C / 2 kg): 33 g / 10 min.

EXAMPLE 9

  In a 2 l flask equipped with a stirrer, a reflux condenser and a contact thermometer, 400 g of granules of a ternary copolymer E / t-BA / VAC (composition: 19.8 t-BA, 2.9% VAC), m.p. (190 C / 2 Kg): 140 g / 10 min, with 1.600 ml ethyl acetate. 60% is added immediately in two portions, 40% after 2 hours of reaction at 70 ° C., twice the theoretical amount of concentrated sulfuric acid (61 g) relative to the amount of t-BA contained in the ternary copolymer. After another 2 hours of reaction at 70 ° C., the product is filtered off with suction, washed 4 times with 1 liter of acetone at 50 ° C. each time and dried at 60 ° C. in a vortex bed dryer. 350 g of colorless granules containing 10% AS, 1.9% are obtained. t-BA and 2.8% VAC, melt index (190 C / 2 Kg) 39 g / 10 min.

EXAMPLE 10

  In a 2 l flask equipped with a stirrer, a reflux condenser and a contact thermometer, 300 g of granules of a copolymer E / t-BA / VAC (composition: 19.0%) are placed. t-BA, 3.3% VAC), m.p. (190 C / 2 Kg): 110 g / 10 min, and

1,200 ml of isopropanol.

  At 75 ° C., 5 hours of continuous reaction are added continuously.

  28 g of toluene-4-sulphonic acid monohydrate, ie 1/3 of the amount

  equivalent to the amount of copolymerized t-BA, dissolved in 150 ml of 85% formic acid. After a further 5 h of reaction at 75 ° C., the granules are filtered off, washed 4 times for 30 minutes with 1 liter of isopropanol at 75 ° C. each time and dried at 60 ° C. under vacuum. 274 g of colorless granules containing 5.1% of AS, 9.9% of t-BA and 3.2% of VAC are obtained, melt index (190 C / 2 kg): 48 g / 10 min.

Claims (4)

  1. A process for the preparation of ethylene copolymers containing more than 50% by weight of ethylene, from 0 to 25% by weight of C 3 -C 12 alkenotech esters and C 3 -substituted alcohols C 8 and / or C 4 -C 8 tertiary alcohols, from 0 to 25% by weight   weight of a vinyl ester of a mono-substituted aliphatic carboxylic acid   basic saturated containing 6 carbon atoms, from 1 to 25%   the weight of C 3 -C 12 alkenotic acids and, where appropriate,   minor portions of other customary monomers copolymerizable with ethylene, by polymerization of monomer mixtures consisting, as such, of at least 50% by weight of ethylene, 2 to 50% by weight of alkenotec acid esters in C 3-C 12 and C 3 -C 8 secondary alcohols and / or tertiary C 4 -C 8 alcohols, 0 to 30% by weight of a saturated monobasic aliphatic carboxylic acid vinyl ester containing from 1 to to 6 carbon atoms, up to 37% by weight of C 3 -C 12 alkenoic acids and minor proportions of other monomers copolymerizable with ethylene, at pressures of 100   at 8000 bars and temperatures from 150 to 350 C in the presence of   catalytic properties of radical initiators, this process is   stabilizing by suspending a part by weight of   copolymer particles having a size of 0.1 to 8 mm, preferably 1 to 5 mm, in 1 to 12 parts by weight of a ketone, an alcohol or an ester corresponding to the general formulas RC- R ', R-OH and R-COOR' wherein R and R ', having identical or different meanings, each represents a straight or branched C 1 -C 6 alkyl group, and the alkenoic acid esters contained in the polymer at temperatures of 40 to 75 C in the presence of acid catalysts.   2. Method according to claim 1, characterized in that one suspends a part by weight of particles of the copolymer in 2 to 6 parts by weight of ketone, alcohol or ester. 3. Process according to claim 1 or 2, characterized in that the copolymer particles are suspended in acetone, methyl ethyl ketone, methyl isobutyl ketone, propanol, isopropanol, butanol and isobutanol. , methyl, ethyl, propyl, butyl or isobutyl acetate or their mixtures.   4. Method according to any one of the claims   1 to 3, characterized in that the acid is used as catalyst   sulfuric acid or p-toluenesulfonic acid.