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
  • C08F8/00—Chemical modification by after-treatment
  • C08F8/14—Esterification

Definitions

• the present invention relates to new crosslinked copolymers of ethylene and of an unsaturated acid ester as well as a process for their production and their application in the manufacture of industrial articles.
• Copolymers of ethylene and at least one (meth) acrylic ester are well known and have found
• copolymers are generally only usable
• the object of the present invention is to remedy the drawbacks of the crosslinking of the copolymers
• patent GB-A-936,732 describes the reaction of a copolymer of a vinyl monomer and of an unsaturated acid ester with a hydroxyl organic compound such that a transesterification takes place and that the ester group of the copolymer is replaced by an appropriate radical derived from the hydroxyl organic compound.
• vinyl may be ethylene;
• the unsaturated acid can be (meth) acrylic acid;
• the hydroxyl organic compound can be a dihydric or polyhydric alcohol such as a glycol, for example a polyethylene glycol having a molecular weight of 100 to 800.
• the transesterification is preferably carried out in the presence of an acid catalyst (sulfuric, phosphoric, hydrochloric, benzene and toluenesulfonic) and at a temperature of 50 ° C to 120 ° C.
• Example 6 describes the reaction of polyethylene glycol on a copolymer comprising 75% by weight of ethylene and 25% by weight of ethyl acrylate, having a molecular weight
• crosslinking is impossible under these conditions because the first hydroxyl function of a polyhydric alcohol is much more reactive than the other hydroxyl functions of said alcohol: once the esterification is carried out by reaction of a hydroxyl end, the polyhydric alcohol fixed on the polymer loses mobility and therefore reactivity.
• a problem which the present invention aims to solve therefore consists in determining the conditions under which a copolymer of ethylene and at least one ester of acrylic or methacrylic acid can be
• Another problem which the present invention aims to solve consists in developing a crosslinked copolymer based on ethylene and at least one ester of acrylic or methacrylic acid, said
• the present invention is based on the discovery that these two problems can be simultaneously resolved by choosing the melt index of the copolymer
• the first object of the present invention is ethylene / (meth) acrylic ester in a certain range and by subjecting it to a transesterification crosslinking reaction at high temperature with a polyol in an amount such that the molar ratio of the hydroxyl functions of the polyol to the ester functions of the copolymer does not exceed 1.
• copolymer comprising units derived from ethylene and units derived from an unsaturated acid ester by reaction with at least one polyol, characterized in that said copolymer having a melt index of 0.2 to 20 dg / min. approximately is subjected to a cross-linking transesterification reaction at a temperature of approximately 150 to 250 ° C. and at a pressure of between 1 and 100 bars approximately, the molar ratio of the hydroxyl functions of the polyol to the ester functions of the copolymer being at most equal to 1.
• the unsaturated acid preferably having ethylenic unsaturation adjacent to the carboxylic group.
• the unsaturated acid is preferably a mono-acid such as acrylic acid, methacrylic acid, acid
• the unsaturated acid ester can be a mono-ester or, preferably, a diester.
• the alcohol from which the unsaturated acid ester is derived preferably comprises from 1 to 8 carbon atoms.
• the esterifying group can be linear or branched, such as for example methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, isoamyl, n-hexyl, 2-ethylhexyl or isooctyl.
• the polyol with which the copolymer is reacted in accordance with the transformation process according to the invention is preferably chosen so as to be in the liquid state under the conditions (temperature, pressure) under which the cross-linking transesterification reaction is carried out.
• alkylene glycols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, the alkanediols preferably carrying the hydroxyl radicals in ⁇ , ⁇ such as 1,4-butanediol, 2,2-dimethyl-1,3-propanediol, 2-ethyl-2-methyl-1,3 -propanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, as well as polyethylene glycols having a molecular weight up to approximately 1000, 1,3-butanediol, neopentylg
• 1,4-cyclohexanediol 2,2,4-trimethyl-1,3-pentanediol, 2-ethyl-2-methyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, trimethylolethane, trimethylolpropane, glycerol, pentaerythritol, dipentaerythritol and polyols mono- or polyethoxylated or mono or polypropoxylated.
• starting copolymer is chosen in a range from 0.2 to 20 dg / min. about.
• the crosslinked copolymers according to the invention obtained from a copolymer with a melt index greater than 30 dg / min. indeed have insufficient mechanical properties which make them unsuitable for most of the envisaged applications.
• the transformation process according to the invention is applicable regardless of the proportion of units derived from the unsaturated acid ester in the copolymer. In most cases, this proportion is between 1 and 50% in moles approximately, preferably between 2 and 35% in moles approximately.
• the copolymer obtained from the transformation process according to the invention can, when the polyol used is a diol of formula HO- (CH 2 ) x -OH, be
• n represents the number of units derived from ethylene for a unit derived from the ester and x is an integer between 1 and 70 approximately.
• the copolymer obtained can be represented by a general formula similar to formula (I) but in which a multifunctional network node appears.
• copolymer subjected to the transformation process according to the invention can, in addition to the units derived from
• the anhydride present can be chosen from citraconic anhydride, itaconic anhydride,
• maleic anhydride When maleic anhydride is used and the polyol used is a diol of formula HO- (CH 2 ) x -OH, the copolymer obtained after transformation according to the invention can be represented by formula (II) on the following page , in which
• n represents the number of units derived from ethylene for a unit derived from the ester
• m represents the number of units derived from ethylene for a unit derived from anhydride
• x is an integer between 1 and 70 about.
• copolymer subjected to the transformation process according to the invention can, in addition to the units derived from
• the glycidyl monomer can be chosen in particular from glycidyl methacrylate and acrylate, monoet diglycidyl itaconate, mono-, di- and triglycidyl butenetricarboxylate.
• the copolymer obtained after transformation according to the invention can be represented by formula (III) on the following page , in which
• n represents the number of units derived from ethylene for a unit derived from the ester
• m represents the number of units derived from ethylene for a unit derived from glycidyl methacrylate
• x is an integer between 1 and 70 about.
• copolymer subjected to the transformation process according to the invention can, in addition to the units derived from
• Such a copolymer is obtained by reacting at a temperature between 150 ° C and 300 ° C an aminoalkylcarboxylic acid on an ethylene terpolymer / unsaturated acid ester / acid anhydride
• the copolymer obtained after transformation in accordance with the invention can be represented by the formula (IV) on the following page, in which n is the number of units derived from ethylene for a unit derived from the ester, m represents the number of units derived ethylene for a unit derived from N-carboxyalkylimide and x is an integer between 1 and 70 approximately.
• copolymer subjected to the transformation process according to the invention can, in addition to the units derived from
• polyol polymethacrylate these may be present in a proportion of up to approximately 0.4 mol% in the copolymer.
• poly (meth) acrylate forming part of such copolymers is meant any compound derived from a polyol and comprising at least two ester functions obtained by at least partial esterification of said polyol using acrylic or methacrylic acid. It can be a diol (di) methacrylate, triol, tetrol, etc., a triol tri (meth) acrylate, tetrol, etc., a tetra (meth) acrylate of a polyol having at least 4 alcohol functions.
• N-carboxyalkylimide of unsaturated dicarboxylic acid and / or of a poly (meth) acrylate are possible for the copolymer subjected to the transformation process according to the invention provided that they do not lead to its crosslinking during its synthesis and, therefore, combinations from the general formulas (II) to (IV) are possible to represent the inventive copolymers obtained after transformation.
• the molar ratio of the hydroxyl functions of the polyol to the ester functions of the copolymer is at most equal to 1. More particularly, this molar ratio is between 0.1 and 0.7 approximately, and more preferably it is between 0.15 and 0.5 approximately. In this way, the transesterification reaction is most often partial, while the crosslinking reaction is total or almost total. For this reason, the general formulas (I) to (IV) may be supplemented to indicate the presence, on the macromolecular chains, of units of formula:
• R 1 is chosen from the hydrogen atom and the alkyl groups (generally the methyl group) and R 2 is chosen from the alkyl groups preferably having from 1 to 8 carbon atoms, these units corresponding to the ester unsaturated acid that has not been transesterified.
• a duration of between 3 and 30 minutes approximately is generally sufficient for the implementation of the method according to the invention, this duration being of course the shorter the higher the implementation temperature.
• transesterification catalyst there may be mentioned acid catalysts such as sulfuric, hydrofluoric, hydrochloric, benzenesulfonic, paratoluenesulfonic acids, ion exchange resins, as well as basic catalysts such as lithium aluminum hydride, oxide and l hydroxide, alkyllithium, lithium tetraalkylborides, lithium and sodium carbonates, soda, sodium alcoholates, phosphates
• alkyltin such as dibutyltin oxide and dioctyltin oxide), dibutyltin dilaurate,
• transesterification catalyst to be used, which varies depending on the nature of the catalyst, is generally between 0.5 and 5% by weight of the total weight of the monomers present.
• the transformation process according to the invention can be implemented in any suitable kneading equipment or any plastic processing machine (vulcanization press, internal kneader, extruder with heating), if necessary comprising a device allowing '' remove the alcohol formed by transesterification.
• any suitable kneading equipment or any plastic processing machine vulcanization press, internal kneader, extruder with heating
• a device allowing '' remove the alcohol formed by transesterification comprising a device allowing '' remove the alcohol formed by transesterification.
• the presence of a small amount of alcohol in the crosslinked copolymer obtained is not detrimental to the qualities of the latter.
• an absorbent material such as a filler such as chalk, oxide calcium, diatomaceous earth, zeolites or kieselglick, in an amount up to 100 parts by weight, advantageously from 5 to 50 parts by weight, per 100 parts of copolymer.
• the crosslinked copolymers obtained by the process according to the invention have, compared to the copolymers from which they are derived, improved mechanical properties, better resistance to oils and better elasticity under compression. They find interesting applications in particular for coating metal cables, obtaining rods, tubes, pipes, profiles obtained by extrusion or in the form of industrial articles of various shapes obtained by injection.
• transesterification-crosslinking generally takes place during and / or after the shaping of the copolymer, depending on whether the shaping temperature reaches or does not reach the temperature range - 150 ° C. to 250 ° C. - in which said reaction begins to take place. It is possible, for example, to inject all the ingredients of the composition into a hot mold, mixed at a temperature below the transesterification temperature, or else by extruding the composition and passing the extrudate through an oven.
• copolymer (C) is chosen from the following products: C 1 : ethylene copolymer (86.5 mol%),
• butyl acrylate (1.1 mole%) having a flow index (ASTM D-1238 standard, 190oC, 2.16 kg) equal to 2.8 dg / min.
• butyl acrylate (8.6 mol%), having a melt index of 4 dg / min.
• composition is kneaded at a temperature of 75oC for 5 minutes then it is introduced into a press where the crosslinking is carried out at 200oC (except in Example 4: 220oC), under a pressure of 50 bars and for the duration t (expressed in minutes) indicated in the table below.
• the rate of frost after a stay of. 48 hours of the copolymer of Example 1 in cyclohexane at 23 ° C is equal to 89%.

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• Chemical & Material Sciences (AREA)
• General Chemical & Material Sciences (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
• Polyesters Or Polycarbonates (AREA)

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• 1989
  • 1989-03-16 FR FR8903453A patent/FR2644464A1/fr active Pending
• 1990
  • 1990-03-15 JP JP2504955A patent/JPH04505169A/ja active Pending
  • 1990-03-15 EP EP90904862A patent/EP0426782A1/de not_active Withdrawn
  • 1990-03-15 WO PCT/FR1990/000172 patent/WO1990010654A1/fr not_active Application Discontinuation
  • 1990-03-15 KR KR1019900702459A patent/KR920700234A/ko not_active Application Discontinuation
  • 1990-03-15 CA CA002026884A patent/CA2026884A1/fr not_active Abandoned

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