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
  • C08F2/00—Processes of polymerisation
  • C08F2/04—Polymerisation in solution
  • C08F2/06—Organic solvent
• • 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
  • C08F2/00—Processes of polymerisation
  • C08F2/12—Polymerisation in non-solvents
  • C08F2/16—Aqueous medium
  • C08F2/22—Emulsion polymerisation
  • C08F2/24—Emulsion polymerisation with the aid of emulsifying agents
  • C08F2/26—Emulsion polymerisation with the aid of emulsifying agents anionic
• • 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
  • C08F218/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an acyloxy radical of a saturated carboxylic acid, of carbonic acid or of a haloformic acid
  • C08F218/02—Esters of monocarboxylic acids
  • C08F218/04—Vinyl esters
  • C08F218/08—Vinyl acetate

Definitions

• the invention relates to processes for the preparation of inylacetate-ethylene copolymers by means of emulsion polymerization, the vinyl acetate-ethylene copolymers obtainable in this way and their use in adhesives, in particular for the bonding of polymer substrates with cellulosic materials.
• Methods of emulsion polymerization of vinyl acetate with ethylene, optionally with further comonomers, in the aqueous phase for the preparation of polymer dispersions have long been known.
• water-soluble polymers for example polyvinyl alcohols, cellulose derivatives or polyvinylpyrrolidone
• protective colloids for example polyvinyl alcohols, cellulose derivatives or polyvinylpyrrolidone
• emulsifiers or surfactants for example, DE-OS 1595402 describes processes in which at least 75% of the vinyl acetate monomer is initially charged in order to improve the ethylene incorporation rate into vinyl acetate-ethylene copolymers and is polymerized in the presence of emulsifiers.
• VAE dispersions based on vinyl acetate and ethylene (VAE dispersions) which are obtainable in this way are used, for example, as binders, in particular for adhesives, paints or fibers. Fleece weave, used.
• VAE dispersions have become more and more specific over the years.
• adhesives are becoming increasingly demanding for bonding materials with low surface energy, for example when bonding polymer films with cellulosic materials, such as paper or cardboard.
• Common VAE dispersions such as, for example, the products according to DE-OS 1595402 or US Pat. No. 3,644,262, are unsuitable for this purpose because they cause too little adhesion of the adhesive bond. Therefore, various attempts have been made to provide VAE dispersions with improved adhesion.
• US-A-3,708,388 discloses vinyl acetate-ethylene copolymer based adhesives stabilized with alkylphenol ethoxylate emulsifiers and optionally protective colloids and having a defined Intrinsic Viscosity and can be used to lamination of films. At least 75% of the vinyl acetate is used in the preparation. To improve the mechanical strength at high temperatures, the use of crosslinking agents is recommended.
• EP 1212383 A1 describes processes for the preparation of adhesives with improved adhesion by preparing aqueous polymer dispersions by means of emulsion polymerization and, after the polymerization has ended, with emulsifiers.
• EP 1212383 A1 teaches that an improvement in the adhesion only occurs with subsequent addition of the emulsifiers, whereas the use of emulsifiers during the polymerization does not lead to an improvement in the adhesion.
• no adhesives having a property level with high cohesion and high adhesion are accessible with products according to EP 1212383 A1; For example, the adhesion to polyester films is too low and the setting speed of the dispersions too low.
• EP 890625 A1 describes vinyl acetate-ethylene polymer dispersions which fulfill certain values for a storage modulus of the polymer and are recommended as an adhesive for hard-to-bond top surfaces, such as polyethylene, polyester, metallized polyester and oriented polypropylene.
• a storage modulus of the polymer such as polyethylene, polyester, metallized polyester and oriented polypropylene.
• the use of regulators is recommended and in the polymerization process, less than 15% of the vinyl acetate is initially charged in the reactor charge, and the vinyl acetate content during the polymerization is kept below 5%.
• Polymer dispersions obtainable in this way have a high adhesion to difficult to bond polymer films. Unfortunately, the cohesion of the adhesive film is too low.
• alkylphenol ethoxylates having 4 to 100 ethylene oxide units are used as nonionic emulsifiers. However, such emulsifiers are frowned upon because of their environmental and health impact.
• EP 385734 A1 recommends certain vinyl acetate-ethylene polymers for adhesives having high setting rates.
• To prepare the vinyl acetate-ethylene copolymers mixtures of partially hydrolyzed polyvinyl alcohols and nonionic polyoxyethylene emulsifiers with defined HLB are used. Characteristic of the polymerization process is that 40 to 90 wt .-% of the vinyl acetate are emulsified in an aqueous solution containing the total amounts of polyvinyl alcohols, emulsifiers and reducing agent, so that a stable emulsion is formed and then after pressing ethylene, the remaining 10 be dosed to 60 wt .-% of vinyl acetate. Disadvantageously, this procedure also does not lead to copolymers having a property level with high cohesion and high adhesion; Adhesion to polyester films is too low.
• EP 279384 A1 describes vinyl acetate-ethylene polymer dispersions which are suitable as packaging adhesives and teaches that a combination of low molecular weight polyvinyl alcohols and nonionic emulsifiers to stabilize the dispersion additionally improves the setting speed of the adhesive even at high solids content.
• the low molecular weight polyvinyl alcohol is initially charged at least partially and the emulsifier fraction is completely introduced.
• so available products cause too little adhesion between cellulosic materials and polyester films.
• GB-A 1546275 describes vinyl acetate-ethylene polymer dispersions which, when used as pressure-sensitive adhesives, have a good balance of tack, cohesion and adhesion.
• examples using only hydroxyethylcellulose as the protective colloid and nonionic emulsifier and the comparative examples show, to achieve good adhesion, the use of chain regulators and a protective colloid content of not more than 1% by weight, based on the total monomer, are required.
• GB-A 1546275 also calls for intrinsic viscosity numbers between 0.6 and 1.0 dl / g. Although the products thus obtained have good adhesion properties, it is disadvantageous that the cohesion is too low and the setting speed too low.
• US Pat. No. 4,269,090 deals with adhesives which improve the wettability of polyvinyl chloride substrates and the setting speed with simultaneously high cohesion.
• US Pat. No. 4,269,090 recommends vinyl acetate-ethylene polymer dispersions obtained by using defined amounts of preferably nonionic emulsifiers the.
• the polymers obtainable in this way can not satisfy a property level with high cohesion and high adhesion, since the adhesion values for polyester films are too low.
• US-A-3769151 is concerned with providing vinyl acetate-ethylene copolymer dispersion based adhesives having improved adhesive properties, particularly to vinyl polymers, while improving thickening response. Described is a complex process of seed emulsion polymerization of vinyl acetate, 5 to 20 wt .-% of ethylene in the copolymer and 0.01 to 1 wt .-% of unsaturated acids, using a mixture of partially hydrolyzed and vollverseiften polyvinyl alcohols, wherein for the preparation of the Seeds only partially saponified polyvinyl alcohol, and in the seed polymerization, a blend with higher-saponified polyvinyl alcohol is used.
• Nonionic, cationic or anionic emulsifiers have no influence on the adhesive and cohesive properties of the vinyl acetate-ethylene copolymer dispersions.
• the emulsion polymerization is carried out in the presence of polyvinyl alcohol and anionic emulsifier Aerosol MA, a diester of sulfosuccinic acid having 6 C atoms in the alkyl radical, or in the presence of nonionic nonylphenol ethoxylate, or nonionic ethylene oxide-propylene oxide block copolymer or unsaturated nonionic ethoxylated emulsifier.
• US-A 3,769,151 describes a "not vinyl adhesion test" for determining a "creep resistance” time, which essentially characterizes the cohesion.
• aqueous polymers according to US Pat. No. 3,769,151 have a high cohesion, the adhesion to polymer substrates, in particular to polyesters, is too low, so that no property level with high cohesion and high adhesion is achieved.
• DE-A 102009001097 describes protective colloid- and emulsifier-stabilized dispersions of vinyl acetate-ethylene polymers and their use in adhesives, the emulsifiers being nonionic emulsifiers, optionally in combination with small amounts of anionic emulsifiers.
• DE-A 102009001097 discloses ethylene-vinyl acetate copolymers which are prepared by means of emulsion polymerization in the presence of protective colloids and selected nonionic emulsifiers and, when used as or in adhesives, exhibit a so-called balanced adhesion cohesion balance of the ethylene-vinyl acetate copolymers ,
• the prior art thus provides vinyl acetate-ethylene copolymers which, when used in adhesives, either have a high cohesion of the adhesive film or a high adhesion of the adhesive film to polymer substrates, but can not achieve a property level with high cohesion and high adhesion.
• vinyl acetate-ethylene copolymers in the presence of
• Protective colloids stabilized mostly polyvinyl alcohol is used.
• the amount of protective colloid used it is known from GB-A 1546275 that proportions of more than 1% by weight, based on monomer, adversely affect the adhesion.
• Emulsifiers are often used for additional stabilization of the polymer particles.
• Nonionic emulsifiers, in particular alkylphenol ethoxylates, are frequently used, whereas according to GB-A 1546275 the use of anionic emulsifiers is disadvantageous.
• EP 1212383 Al and US 3769151 the use of emulsifiers during the emulsion polymerization does not affect the adhesive properties of the products.
• EP 1212383 Al it is known from EP 1212383 Al that the subsequent addition of emulsifiers to a polyvinyl alcohol-stabilized dispersion can improve the adhesion.
• Adhesion is understood to mean the adhesion between a substrate and an adhesive film produced from an aqueous dispersion of a vinyl acetate-ethylene copolymer.
• Cohesion refers to the cohesion within the adhesive film produced from an aqueous dispersion of a vinyl acetate-ethylene copolymer.
• the minimum requirements for a property level with high cohesion and high adhesion of an adhesive can be quantified by the following parameters, according to which the adhesive preferably has an adhesive film with a cohesion, measured as heat resistance, of at least 0.2 N / mm 2 , preferably at least 0.4 N / mm 2 , and preferably simultaneously fulfilling the following adhesion parameters:
• Adh PS is preferably at least 3.8 N / cm, where Adh PS is the peel strength, that is an adhesive bond made of cotton and polystyrene Silveraplex® Polyflex 90 (PS film) at a peel rate of 5 mm / min;
• Adh PET1 is preferably at least 3.4 N / cm, with Adh
• PET1 is the peel strength exhibited by an adhesive-bonded composite of cotton and Hostaphan® RN125 polyethylene terephthalate film (PET film) at a peel rate of 10 mm / min; and
• Adh PET2 is preferably at least 1.2 N / cm, PET2 being the peel strength, and the cotton-bonded and polyethylene terephthalate film Hostaphan® RN125 (PET film) being made by adhesive bonding at a peel rate of 900 mm / min.
• the minimum requirements for a property level with high cohesion and high adhesion of an adhesive further include that it satisfies a liability sum, HS, of HS preferably 18, in particular HS ⁇ 17.
• adhesive films of aqueous dispersions of vinyl acetate-ethylene copolymers should have a high setting speed of, that is to say in particular, a tightening speed. speed (AZG) of preferably 3.0 seconds or less.
• the objects were in particular due to the synergistic interaction of ethylene content of vinyl acetate-ethylene copolymers and the use of solvents, in particular alkyl alcohols, and optionally certain amounts of special anionic sulfosuccinic dissolved in the emulsion polymerization for the preparation of vinyl acetate-ethylene copolymers.
• GB81625, GB682773 and GB895153 describe the addition of methanol, ethanol, ethylene glycol, glycerol, acetone or methyl acetate as an antifreezing agent, for example when carrying out polymerizations below 0 ° C.
• GB1018448 it is stated that acrylate dispersible by the addition of methanol, ethanol or isopropanol can be coagulated after synthesis to separate the polymers; the same also in GB548356 and in GB601807.
• Alcohols such as methanol or ethanol, used for the purification of polymers.
• GB621467 describes the emulsion polymerization of conjugated diene compounds, such as butadiene, optionally with styrene or chlorinated styrene in an aqueous, alcoholic medium.
• GB573366 mentions the utility of water / ethanol mixtures as a medium for vinyl chloride emulsion polymerization to increase VC solubility in the aqueous phase.
• US Pat. No. 4,708,139 describes the emulsion polymerization of cationic latices (acrylates / amino group-modified acrylates) in water / alcohol mixtures to improve colloidal stability and to reduce particle aggregation processes and to improve the mechanical stability of the dispersions.
• solvents mention may be made of alcohols, glycols, esters, cyclic ethers, hydroxylated ethers.
• DE1123470 describes the use of special cationic surfactants and solvents, such as methanol or hexylene glycol, in the emulsion polymerization of vinyl esters.
• R0116556 describes vinyl acetate / acrylate emulsion polymerizations in the presence of anionic and nonionic emulsifiers and coalescing aids from the group acetone or ethanol.
• JP11209430 describes the emulsion polymerization of ⁇ meth) acrylates in the presence of cyclic organic phosphates in water / alcohol mixtures. No.
• 3,577,376 describes the emulsion polymerization of vinyl acetate and acrylamide, wherein alkyl alcohols, in particular methanol, but also ethanol, i-propanol and t-butanol, and also other solvents such as formamide, dimethylformamide, dimethylacetamide, dimethyl sulfoxide, as "solubilizing agents" for solution DE2512589 describes self-crosslinking vinyl acetate-ethylene copolymers consisting of ethylene, vinyl acetate, a copolymerisable N-methylol compound, (meth) acrylic acid radicals (n), an unsaturated carboxylic acid and polyunsaturated monomers.
• Dispersants in example 8 of DE 2512589, a polymerization is carried out in the absence of protective colloid in the presence of methanol, in which case methanol can counteract the formation of coarse particulates (sieve residue)
• DE 1770395 relates to binders for pigments and fillers for paints so as additional
• the weight ratio of vinyl chloride to ethylene is 1: 2 to 3: 1.
• solvents serve, for example, as "antifreezing agents", to improve colloidal stability and to avoid particle aggregation processes, such as the formation of sieve residue or to improve shear stability
• vinyl acetate (co) polymers obtained in the presence of solvents are used as adhesives for bonding, for example, cellulosic materials, such as paper or paperboard, with polymer substrates, in particular with polystyrene and polyester films not suitable because they do not cause sufficient adhesion and / or sufficient cohesion.
• the invention relates to processes for the preparation of vinyl acetate-ethylene copolymers by free-radically initiated emulsion polymerization of vinyl acetate, ethylene and optionally one or more other comonomers in the presence of at least one protective colloid and optionally at least one emulsifier, characterized in that
• the vinyl acetate-ethylene copolymers 18 to 45 wt .-% of ethylene len units, based on the total weight of the vinyl acetate-ethylene copolymers, and
• R 1 is a linear or branched alkyl radical having 4 to 17 C atoms, an alkylene oxide group - ⁇ R z -O) n -X or a cation M, where
• R 2 is a linear or branched alkylene unit having 2 to 5 C atoms
• n is equal to an integer value of 2 to 20 and
• X is a linear or branched alkyl radical having 4 to 17 C atoms
• Another object of the invention are vinyl acetate-ethylene copolymers obtainable by free-radically initiated emulsion polymerization of vinyl acetate, ethylene and optionally one or more other comonomers in the presence of at least one protective colloid and optionally at least one emulsifier, characterized in that
• the vinyl acetate-ethylene copolymers 18 to 45 wt .-% of ethylene len units, based on the total weight of the vinyl acetate-ethylene copolymers, and
• ethylene units at least 70 wt .-% of ethylene units, based on the total weight of the ethylene units and the other comonomer units of vinyl acetate-ethylene copolymers, and contain
• the vinyl acetate-ethylene copolymers are obtainable by free-radically initiated emulsion polymerization in the presence of
• R 1 is -O-CO-CH 2 -CH (SO 3 ) -CO-OR 1 (I)
• R 1 is a linear or branched alkyl radical having 4 to 17 C atoms, an alkylene oxide group - (R 2 -O) n -X or a cation M, where
• R 2 is a linear or branched alkylene unit having 2 to 5 C atoms
• n is equal to an integer value of 2 to 20 and
• X is a linear or branched alkyl radical having 4 to 17
• the individual radicals X, R 1 and R 2 and M and the parameter n of the general formula (I) can each independently assume their meaning.
• the abbreviation C-Atom stands for a carbon atom.
• the anionic sulfosuccinic acid esters of the general formula (I) are a special embodiment of anionic emulsifiers.
• the term monomers stands for ethylenically unsaturated compounds and includes vinyl acetate, ethylene and the optionally present further comonomers and auxiliary monomers.
• alternative B the embodiments of the present invention in which one or more anionic sulfosuccinic acid esters of the general formula I are compulsorily used are designated as alternative B).
• alternative A the other embodiments which do not require the use of the abovementioned sulfosuccinic esters are referred to below as alternative A).
• Ethylene or ethylene units have the chemical empirical formula C 2 H 4 .
• the proportion of ethylene units in the vinyl acetate-ethylene copolymers is preferably from 19 to 40% by weight, more preferably from 20 to 35% by weight, and most preferably from 22 to 32% by weight, based in each case on the total weight the vinyl acetate-ethylene copolymers. In general, the proportion of vinyl acetate units in the
• Vinyl acetate-ethylene copolymers 60 to 81 wt .-%, preferably 65 to 80 wt .-%, particularly preferably 68 to 78 wt .-%, and am Most preferably 68 to 76 wt .-%, each based on the total weight of the vinyl acetate-ethylene copolymers.
• vinyl esters of carboxylic acids having 3 to 18 carbon atoms are preferred vinyl esters.
• Preferred vinyl esters are vinyl propionate, vinyl butyrate, vinyl 2-ethylhexanoate, vinyl laurate, 1-methylvinyl acetate, vinyl pivalate and vinyl esters of ⁇ -branched monocarboxylic acids having 9 to 11 C atoms, for example VeoVa9® or VeoValO® (trade names of Hexion ).
• Suitable further comonomers are also those from the group of esters of acrylic acid or methacrylic acid of unbranched or branched alcohols having 1 to 15 carbon atoms.
• Preferred methacrylic esters or acrylic esters are esters such as methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, n-butyl acrylate, n-butyl methacrylate, 2-ethylhexyl acrylate, norbornyl acrylate.
• Suitable comonomers are also vinyl halides such as vinyl chloride, or vinyl aromatics such as styrene, or olefins such as propylene.
• the further comonomers are preferably used at 1 to 19% by weight and more preferably at 2 to 15% by weight and most preferably 2 to 10% by weight, based in each case on the total amount of vinyl acetate and ethylene.
• auxiliary monomers are used.
• Hilfsmonoraere are ethylenically unsaturated mono- and dicarboxylic acids, preferably acrylic acid, methacrylic acid,
• Fumaric acid and maleic acid ethylenically unsaturated carboxylic acid amides and nitriles, preferably acrylamide and acrylonitrile; Mono- and diesters of fumaric acid and maleic acid, such as diethyl and diisopropyl esters, and also maleic anhydride, ethylenically unsaturated sulfonic acids or salts thereof, preferably vinylsulfonic acid, 2-
• Acrylamido-2-methylpropanesulfonic acid examples are precrosslinking comonomers such as polyethylenically unsaturated comonomers, for example divinyl adipate, diallyl maleate, allyl acrylate or triallyl cyanurate, or post-crosslinking comonomers, for example acrylamidoglycolic acid (AGA), methylacrylamidoglycolic acid methyl ester (MAGME), N-methylolacrylamide (NMA), N-methylolmethacrylamide (NMMA), N-methylolallyl carbamate, alkyl ethers such as the isobutoxy ether or esters of N-methylolacrylamide, N-Methylolmethacrylamids and N-Methylolallylcarbamats.
• precrosslinking comonomers such as polyethylenically unsaturated comonomers, for example divinyl adipate, diallyl maleate
• epoxide-functional comonomers such as glycidyl methacrylate and glycidyl acrylate.
• silicon-functional comonomers such as acryloxypropyltri (alkoxy) - and methacryloxypropyltri (alkoxy) silanes, vinyltrialkoxysilanes and vinylmethyldialkoxysilanes, where as alkoxy groups, for example, methoxy, ethoxy and ethoxypropylene glycol ether radicals may be present.
• methacrylic acid and acrylic acid hydroxyalkyl esters such as hydroxyethyl, hydroxypropyl or hydroxybutyl acrylate or methacrylate
• compounds such as diacetone acrylamide and acetoacetoxyethyl acrylate or methacrylate.
• no N-vinylformamide and / or N-vinylpyrrolidone is copolymerized. It is also preferable not to copolymerize acrylonitrile and / or vinyl halide such as vinyl chloride.
• the proportion of ethylene units in the vinyl acetate-ethylene copolymers is preferably at least 80% by weight, more preferably at least 90% by weight and most preferably at least 95% by weight, based on the total weight of the ethylene units , the further comonomer units and optionally the auxiliary monomer units of the vinyl acetate-ethylene copolymers.
• vinyl acetate-ethylene copolymers which contain no units of further comonomers and / or no units of auxiliary monomers.
• the polymerization takes place after the emulsion polymerization process in an aqueous medium, wherein the polymerization temperature is generally 40 ° C to 100 ° C, preferably 50 ° C to 90 ° C and in particular 60 ° C to 80 ° C.
• the polymerization pressure is generally between 40 and 100 bar, preferably between 45 and 90 bar, and most preferably between 45 and 85 bar.
• the initiation of the polymerization is preferably carried out with the customary for the emulsion polymerization redox initiator combinations.
• Suitable oxidation initiators are the sodium, potassium and ammonium salts of peroxodisulfuric acid, hydrogen peroxide, t-butyl peroxide, t-butyl hydroperoxide, potassium peroxodiphosphate, t-butyl peroxypivalate, cumene hydroperoxide, isopropylbenzene monohydroperoxide, azobisisobutyronitrile. Preference is given to the sodium, potassium and ammonium salts of peroxodisulfuric acid and hydrogen peroxide.
• the initiators mentioned are generally used in an amount of 0.05 to 2.0 wt .-%, based on the total weight of the monomers.
• Suitable reducing agents are the sulfites and bisulfites of the alkali metals and ammonium, for example sodium sulfite, the derivatives of sulfoxylic acid such as zinc or Alkaliformaldehydsulfoxylate, for example, sodium formaldehyde sulfoxylate (Brüggolit®) and formaldehyde derivatives of sulfinic acid and mixtures thereof known under the trade name Brüggolit® FF6 and (Iso) ascorbic acid and tartaric acid. Preference is given to Brüggolit®, Brüggolit® FF6, (iso) ascorbic acid and its salts, e.g. Na isoascorbate, and tartaric acid.
• the amount of reducing agent is preferably 0.05 to 3 wt .-%, based on the total weight of the monomers.
• the redox-initiator combination of hydrogen peroxide and Brüggolit® or Brüggolit® FF6 is preferred.
• hydrogen peroxide is generally used in an amount of from 0.06 to 0.4% by weight, preferably from 0.1 to 0.3% by weight, more preferably from 0.15 to 0.25% by weight, based on the total monomer used.
• the ratio of oxidizing agent to reducing agent is then generally from 10 to 70 to 10 to 3, preferably from 10 to 60 to 10 to 6, and most preferably from 10 to 60 to 10 to 10 parts by weight.
• Preferred protective colloids are partially hydrolyzed or fully hydrolyzed polyvinyl alcohols, so-called standard polyvinyl alcohols, having an average degree of hydrolysis of from 85 to 99.9 mol.
• standard polyvinyl alcohols having an average degree of hydrolysis of from 85 to 99.9 mol.
• polyvinyl alcohols having an average degree of hydrolysis of from 86 to 90 mol%, preferably in each case having a mass-average degree of polymerization of from 600 to 2000.
• fully hydrolyzed standard polyvinyl alcohols having an average degree of hydrolysis of from 96.1 to 99.9 mol%, preferably having an average degree of hydrolysis of from 97.5 to 99.5 mol%, alone or in mixtures with partially hydrolyzed standard polyvinyls are preferred.
• nylalkoholen wherein the fully hydrolysed polyvinyl alcohols are preferably characterized by a mass-average degree of polymerization of 600 to 3500.
• modified polyvinyl alcohols such as those bearing functional groups, such as acetoacetyl groups, or those containing comonomer units, such as vinyl laurate-modified or Versatic acid vinyl ester modified polyvinyl alcohols, or - and preferably - ethylene-modified polyvinyl alcohols, which are known for example under the trade name EXCEVAL®, alone or in combination with said standard polyvinyl alcohols, use.
• Preferred ethylene-modified polyvinyl alcohols have an ethylene content of up to 12 mol%, preferably 1 to 7 mol% and particularly preferably 2 to 6 mol%; in particular 2 to 4 mol%.
• the mass-average degree of polymerization is in each case from 500 to 5000, preferably 2000 to 4500, and particularly preferably 3000 to 4000.
• the average degree of hydrolysis is generally greater than 92 mol%, preferably 94.5 to 99.9 mole%, and more preferably 98.1 to 99.5 mole%.
• Suitable protective colloids are also water-soluble cellulose derivatives, for example and preferably hydroxyethyl cellulose, having viscosities in 2% strength by weight aqueous solutions of ⁇ 6500 mPas, preferably ⁇ 3500 mPas, more preferably ⁇ 1500 mPas and in particular ⁇ 500 mPas.
• Suitable protective colloids are furthermore polyvinylpyrrolidones having cuvettes between 10 and 30.
• Water-soluble means that their solubility in water under normal conditions is> 1 g / 100 ml of water.
• the protective colloids are generally in an amount of 1 to 7 wt .-%, preferably 1.5 to 5.5 wt .-%, particularly preferably 2 to 4 wt .-%, and in particular 2 to 3.5 wt. -%, in each case based on the total weight of the monomers, during the polymerization.
• the protective colloids in particular the polyvinyl alcohols, may be in the form of starting materials which, in addition to one or more protective colloids, contain a proportion of one or more solvents, in particular alkyl alcohols, such as methanol.
• the starting materials preferably contain a proportion of solvents of from 0.1 to 3% by weight, preferably from 0.1 to 2.6% by weight, more preferably from 0.1 to 2.0% by weight, and most preferably 0, 1 to 1% by weight, based in each case on the total mass of the starting material.
• the protective colloids in particular the polyvinyl alcohols, are generally used in the form of starting materials which have up to a maximum of 5% by weight of volatile organic compounds conditions of organic substances and residual moisture, such as water, based on the total mass of the starting materials.
• Feedstocks in addition to protective colloids other ingredients are often included in commercially available protective colloids as impurities.
• An essential aspect of the present invention is the performance of the emulsion polymerization in the presence of one or more solvents.
• the solvents generally give a solution with water and / or vinyl acetate.
• a solution is a single-phase, homogeneous mixture of at least two different substances and is under normal conditions according to DIN50014 in the form of a liquid.
• the solvent is more than 2 g, in particular more than 10 g in 100 g of water and / or in 100 g of vinyl acetate under normal conditions according to DIN50014 soluble.
• suitable solvents are linear or cyclic glycol ethers, in particular diethylene or dipropylene glycol, diols, in particular ethylene glycol or 1,2-propanediol, triols, in particular glycerol, or in general alkyl alcohols, in particular alkyl alcohols having 1 to 5 C atoms.
• Preferred solvents are alkyl alcohols having 1 to 5 C atoms, particularly preferably 2 to 4 C atoms and most preferably 2 to 3 C atoms.
• suitable alkyl alcohols are methanol, ethanol or propanol. Preferred are ethanol or 2Propanol. Preferably, no methanol is added as a solvent in the process according to the invention.
• starting materials used in the abovementioned preferred embodiment of the process according to the invention, for example starting materials containing protective colloids such as polyvinyl alcohols, can not nevertheless contain proportions of methanol. In a particularly preferred embodiment, however, all starting materials, in particular the starting materials, are free of methanol.
• the solvents during the emulsion polymerization are preferably from 0.2 to 10% by weight, more preferably from 0.3 to 5% by weight, still more preferably from 0.3 to 4.2% by weight .%, even more preferably from 0.4 to 4.1, most preferably from 0.6 to 4.1% by weight, and most preferably from 0.8 to 4.0% by weight, based in each case on the total weight of the monomers, which values can be combined in any desired manner.
• the abovementioned amounts of solvents also comprise the proportions of solvent which are introduced into the process according to the invention as an impurity or as an accompanying material of the educts, for example the starting materials, such as any alkyl alcohol impurities of polyvinyl alcohol.
• M is preferably a cation of hydrogen or alkaline earth metals or an ammonium ion, more preferably a cation of the alkaline earth metals or an ammonium ion, and most preferably a cation of sodium or potassium or ammonium.
• Preferred linear or branched alkyl radicals R 1 of the general formula (I) contain at least 4 C atoms, more preferably at least 6 C atoms, even more preferably at least 7 C atoms, more preferably at least 8 C atoms, even more preferably at least 9 C atoms, and most preferably at least 10 C atoms to preferably at most 14 C atoms, and more preferably at most 13 C atoms.
• R l the aforementioned
• Preferred alkylene oxide groups - ⁇ R 2 -O) n -X contain as R 2 preferably a linear or branched alkylene unit having 2 to 3 C atoms and particularly preferably an alkylene unit having 2 C atoms.
• R 2 preferably a linear or branched alkylene unit having 2 to 3 C atoms and particularly preferably an alkylene unit having 2 C atoms.
• n is preferably an integer from 2 to 20, more preferably from 2 to 10, and most preferably from 3 to 6.
• Preferred Alkylene Oxide Groups - (R 2 -O) n -X preferably contain as X, more preferably, even more preferably and most preferably the same linear or branched alkyl radicals which are correspondingly listed for R 1 of the general formula (I).
• R 1 of the general formula (I) are linear or branched alkyl radicals having 4 to 17 C atoms or for alkylene oxide groups - (R 2 -O) n -X; ie preferably no R 1 of the general formula (I) is a cation M.
• Suitable anionic sulfosuccinic acid esters of the general formula (I) are dioctylsulfusuccinate sodium salts or diethylhexylsulfosuccinate sodium salts, also known under the trade names Aerosol® OT or Empimin® OT; or didecylsulfosuccinate sodium salts, also known under the trade names Geropon® DDS65 or Empimin® ID65; or di-isotridecylsulfosuccinate sodium salts, also known under the trade names Geropon® Bis / Sodico or Empim® TR70 or Aerosol® TR70; or monoesters of the sulfosuccinic acid esters of the general formula (I) in which R 1 is - (R 2 -O) n -X and R 2 is an alkylene unit having 2 C atoms, X is a linear or branched alkyl radical having 10 to 12 C atoms and n is an integer
• anionic sulfosuccinic acid esters of the general formula (I) can be used as pure substance, as a mixture with vinyl acetate and / or further comonomers, as a mixture with water, or as a mixture with one or more solvents and optionally water in the process according to the invention.
• anionic sulfosuccinic acid esters of the general formula (I) It is also possible to use mixtures of several anionic sulfosuccinic acid esters of the general formula (I). It is also possible to use one or more anionic sulfosuccinic acid esters of the general formula (I) in admixture with one or more nonionic emulsifiers and / or one or more other anionic emulsifiers.
• nonionic emulsifiers which can be used in admixture with the anionic sulfosuccinic acid esters of the general formula (I) are nonionic, branched or linear alkyl ethoxylated emulsifiers, polyalkylene oxides or block copolymers of alkylene oxides.
• ethoxylated fatty alcohols including oxoalcohols, with branched or straight-chain alkyl radical, where the alkyl radical has 4 to 40 C atoms, preferably 8 to 18 C atoms and is ethoxylated with 2 to 60, preferably 4 to 40 ethylene oxide units.
• C12 to C14 fatty alcohols having 3 to 40 ethylene oxide units examples include C12 to C14 fatty alcohols having 3 to 40 ethylene oxide units, C13 to C15 fatty alcohols (oxo alcohols) having 3 to 40 ethylene oxide units, C16 to C18 fatty alcohols having 11 to 60 ethylene oxide units , C10 ⁇ or C13-fatty alcohols (oxo alcohols) with 3 to 40 ethylene oxide units, polyoxyethylene sorbitan monooleate with 20 ethylene oxide units.
• Particularly preferred ethoxylated fatty alcohols are the polyethylene oxide ethers with 2 to 60 ethylene oxide units of linear alcohols (such as oleyl alcohol, stearyl alcohol) or Iso tridecylalkohol.
• Copolymers of ethylene oxide (EO) and propylene oxide (PO) with an ethylene oxide content of 10 to 40% by weight and a molecular weight of 1500 to 3000 are also preferred as nonionic, ethoxylated emulsifiers.
• Particularly preferred are EO-PO copolymers with an EO content of 10 to 30 wt .-%.
• mixtures of said emulsifiers can be used.
• anionic emulsifiers which can be used in admixture with the anionic sulfosuccinic acid esters of the general formula (I) are linear or branched alkyl sulfates having 2 to 20, preferably 6 to 16, especially 8 to 14 C atoms or ethoxylated anionic emulsifiers , in particular linear or branched alkyl ether sulfates having 4 to 40 carbon atoms and 2 to 40 ethylene oxide units.
• one or more of the anionic sulfosuccinic acid esters of general formula (I) are used in admixture with one or more linear or branched alkyl nonionic ethoxylated emulsifiers or in admixture with one or more nonionic ethylene oxide-propylene oxide copolymers.
• the anionic sulfosuccinic acid esters of general formula (I) are in alternative B) generally in an amount of from 0.5 to 4 wt .-%, preferably 0.8 to 3.5 wt .-%, particularly preferably 1.0 to 3.0 wt .-%, and most preferably 1.2 to 2.7 wt .-%, each based on the total weight of the monomers, during the emulsion polymerization.
• the proportion of anionic emulsifiers, preferably of the anionic sulfosuccinic acid esters of general formula (I), in alternative B) is generally at least 10% by weight, preferably at least 30% by weight, more preferably at least 50% by weight. even more preferably at least 51% by weight, more preferably at least 55% by weight, very preferably at least 60, even more preferably at least 80% by weight, very preferably at least 90% by weight and in particular from 90 to 99 wt .-%, each based on the total weight of the total emulsifiers used in emulsion polymerization.
• the most preferred alternative emulsifiers used in the emulsion polymerization are exclusively the anionic sulfosuccinic acid esters of the general formula (I).
• the anionic sulfosuccinic acid esters of the general formula (I) are generally present in an amount of from 11.1 to 80.0% by weight, preferably 18.6 to 66.7% by weight, more preferably 25.5 to 55.6% by weight and most preferably 37.5 to 53.5% by weight, in each case based on the total weight of the protective colloids and anionic sulfosuccinic acid esters of the general formula (I), during the emulsion polymerization.
• the anionic sulfosuccinic acid esters of general formula (I) are in alternative B) generally in an amount of 10.0 to 79.4 wt .-%, preferably 16.6 to 61.2 wt .-%, particularly preferably 20.5 to 54.2% by weight, and most preferably 24.0 to 51.4% by weight, based in each case on the total weight of the emulsifiers and protective colloids, during the emulsion polymerization.
• the emulsifiers in alternative B) are generally present in an amount of 11.2 to 88.7% by weight, preferably 18.8 to 75.8% by weight, particularly preferably 25.7 to 70.2% by weight. and most preferably from 27.6 to 68.6% by weight, based in each case on the total weight of the emulsifiers and protective colloids, during the emulsion polymerization.
• one or more nonionic or ionic emulsifiers can be used alone or in admixture.
• the aforementioned nonionic or ionic emulsifiers are suitable.
• Ionic emulsifiers are preferably anionic emulsifiers.
• Suitable anionic emulsifiers are listed above in the description of the emulsifiers for alternative B).
• sulfosuccinic acid esters of the general formula (I) are generally excluded from emulsifiers, in particular ionic emulsifiers.
• any emulsifiers used may be used in an amount of 0.1 to 4% by weight, preferably 0.5 to 3.5% by weight and more preferably 1.0 to 3.0% by weight. , based in each case on the total weight of the monomers, during the emulsion polymerization. In preferred embodiments of alternative A) no emulsifiers are used.
• alkylphenol ethoxylates are used as emulsifiers.
• Alkylphenolethoxylates are umweit- and health.
• the solvents may be in the form of mixtures with the monomers,
• Protective colloids and / or optionally emulsifiers, in particular the anionic sulfosuccinic esters of the general formula (I) are introduced.
• mixtures of one or more solvents with one or more protective colloids or premixes containing one or more protective colloids and one or more solvents can be fed to the process according to the invention.
• one or more solvents can be mixed with one or more anionic sulfosuccinic acid esters of the general formula (I) or with premixes comprising one or more anionic sulfosuccinic acid esters of the general formula (I) and one or more solvents and in the form of the mixtures thus obtained be fed to the invention.
• the emulsifiers and / or protective colloids or the abovementioned premixes or starting materials are preferably 0.0 to 3.8% by weight, more preferably 0.5 to 3.8% by weight and most preferably 0, 5 to 3.0 parts by weight of solvent, based on the total weight of the monomers, mixed.
• the solvents can be introduced completely or partially before the initiation of the emulsion polymerization in the reactor or can be added in total or partly during the emulsion polymerization.
• the solvents can be added, for example, to substantial portions during the emulsion polymerization.
• the solvents are preferably distributed in the same ratio as the emulsifiers on initial and dosage. In this case, a greater proportion of the solvent is preferably simultaneously, but optionally spatially separated, with a portion of the anionic sulfosuccinic ester of the general formula (I) added after initiation of the emulsion polymerization as initially charged.
• Vinyl acetate is preferably added to from 10 to 70% by weight, more preferably from 10 to 50% by weight, most preferably from 15 to 50% by weight, and most preferably from 22 to 42% by weight, before initiation of the emulsion polymerization. submitted in the reactor, in each case based on the total weight of the total vinyl acetate used.
• preferably 40 to 100% by weight, more preferably 50 to 100% by weight and most preferably 50 to 75% by weight of ethylene are introduced into the reactor, in each case based on the total weight of the total ethylene used ,
• comonomers or auxiliary monomers can be initially introduced into the reactor before the initiation or added in total during the reaction.
• the other comonomers or auxiliary monomers can also be partially charged and partially metered.
• the protective colloids are preferably initially charged to at least 20% by weight, more preferably at least 50% by weight and most preferably to 100% by weight, prior to initiation of the emulsion polymerization, based in each case on the total weight of the total protective colloids used.
• the protective colloids can be metered to 100%, based on the total weight of the total protective colloids used.
• emulsifiers When emulsifiers are used, they are preferably at least 25% by weight, more preferably at least 40% by weight, most preferably from 55 to 85% by weight and most preferably from 62 to 82% by weight before initiation submitted to the emulsion, in each case based on the total weight of the total used
• Emulsifiers can be metered to 100%, based on the total weight of the total emulsifiers used.
• the solvents are preferably at least 20% by weight, more preferably at least 30% by weight, more preferably at least 40% by weight, and even more preferably at least 50% by weight, most preferably at least 65% by weight. -% and in particular to 80 to 100 % By weight, based in each case on the total weight of the total solvents used, prior to the initiation of the emulsion polymerization. The hereby optionally remaining proportion of solvent is added.
• the solvents may be at least 50% by weight, preferably at least 65% by weight, more preferably at least 85% and most preferably 90 to 100% by weight, based in each case on the total weight of the total used solvents are added after initiation of the emulsion polymerization.
• the hereby optionally remaining proportion of solvent is presented.
• solvents especially alkyl alcohols, at least 50 wt .-%, preferably at least 65 wt .-%, more preferably at least 85 wt .-% and most preferably at 90 to 100 wt .-%, each based on the Total weight of the total solvents used, submitted before initiation of the emulsion polymerization, provided that they are used in a proportion of 0.5 to 4 wt .-%, based on the total monomers used.
• solvents especially alkyl alcohols, at least 50 wt .-%, preferably at least 65 wt .-%, more preferably at least 85 wt .-% and most preferably from 90 to 100 wt .-%, each based on the total weight of the total solvents used, dosed after initiation of the emulsion polymerization during the course of the emulsion polymerization, provided that they are used in a proportion of greater than 4.5 wt .-%, based on the total monomers used.
• the cohesion and / or the adhesion properties of the vinyl acetate-ethylene copolymers obtainable in this way can be selectively increased or controlled not only with the amount but also with the distribution of the solvents on initial and metered additions.
• the initiator is preferably added in total.
• one of the two components is preferably at least partially introduced, particularly preferably, the reducing agent component is at least partially presented.
• the emulsion polymerization according to the invention is generally divided into the following phases or process steps as a whole:
• the procedure is generally such that the stated constituents of the reaction mixture, in particular monomers, protective colloid, solvent and / or optionally emulsifier, are initially charged in the stated proportions, and the initial charge is then heated to polymerization temperature.
• the reactor template is present on a larger scale
• the pH during the polymerization reaction is about 2 to 7, preferably about 3 to 6, and more preferably about 3.5 to
• pH-adjusting agents are known inorganic or organic acids, of which phosphoric acid and formic acid are particularly preferred. It is also possible to add customary buffer substances to the reactor master before the initiation or to meter it in during the reaction, preferably it is possible to dispense with such buffer substances.
• Volatile organic compounds such as residual monomers or solvents
• VOC volatile organic compounds
• entrainers such as nitrogen or preferably water vapor.
• the latter is also known under the term steam stripping.
• the distilling or stripping is preferably carried out at temperatures of 50 to 100 ° C, preferably in vacuo.
• the stripping can also be repeated several times.
• Volatile organic substances have a boiling point of less than 250 ° C at atmospheric pressure.
• the aqueous dispersions of the vinyl acetate-ethylene copolymers have a content of volatile organic substances of preferably ⁇ 2000 ppm and particularly preferably ⁇ 1000 ppm, based on the weight of the aqueous dispersions;
• the proportion of alkyl alcohols is preferably ⁇ 500 ppm, more preferably ⁇ 100 ppm and most preferably from -i 75 ppm, based on the weight of the aqueous dispersions of the vinyl acetate-ethylene copolymers.
• the procedure is such that 22 to 32 wt .-% of ethylene, based on the total monomer vinyl acetate and ethylene; 1.5 to 3.5 wt .-%, based on the total weight of all Mo monomers, to protective colloids, in particular to partially saponified standard polyvinyl alcohols having a mass-average degree of polymerization of from 600 to 2000 and an average degree of hydrolysis of from 86 to 96 mol%, or to fully saponified standard polyvinyl alcohols having a mass-average degree of polymerization of from 600 to 3500 and a mean Degree of hydrolysis of from 96.1 to 99.9 mol%, or of modified polyvinyl alcohols, in particular of ethylene-modified polyvinyl alcohols, having a mass-average degree of polymerization of from 500 to 4500 and an average degree of hydrolysis of from 94.5 to 99.9, or hydroxyethyl cellulose with viscosities, in 2% by weight aqueous solution of -1500
• % By weight of one or more solvents, based on the total weight of the solvents, a part of the reducing agent component and optionally 50 to 85 wt .-% of one or more emulsifiers, based on the total weight of the total emulsifiers used, be submitted before initiation in the reactor ;
• the reactor template is adjusted to a pH between 3 and 5 and heated to a starting temperature of 10 ° C to 60 ° C.
• the reaction can then be initiated by parallel dosing of oxidizing agent hydrogen peroxide and reducing agent Na formaldehyde sulfoxylate, Brüggolit®, or Brüggolit® FF6, and briefly after exothermic reaction start with uniform parallel metering of vinyl acetate, ethylene, water, solvents, optionally emulsifiers and continuing redox initiator dosages.
• the dosages of ethylene, solvents and, if appropriate, emulsifiers may end with the vinyl acetate dosage, preferably the dosages of ethylene, solvents and optionally emulsifiers are terminated before the end of the vinyl acetate dosage.
• the redox initiator doses continue in the polymerization phase until the exothermic reaction subsides and / or the unreacted vinyl acetate content decreases to less than 2% by weight, preferably less as 1 wt .-%, based on the total amount, of aqueous dispersion has decreased.
• the aqueous dispersions of vinyl acetate-ethylene copolymers obtainable in this way have a solids content of generally> 56%, preferably> 58%.
• the viscosity of the aqueous dispersions is generally between 1,000 and 20,000 mPas, preferably between 2,000 and 10,000 mPas, determined as Brookfield viscosity Bf20, at solids contents of 60% and 23 ° C.
• the emulsion polymerization may also be carried out in the presence of a preformed polymer dispersion, often referred to as a seed latex or seed.
• a preformed polymer dispersion often referred to as a seed latex or seed.
• a seed latex or seed For example, it is possible to use a produced by the process according to the invention vinyl acetate-ethylene copolymer as a seed and to submit the seed partially or completely or to dose partially or completely.
• no use of a seed is necessary. Due to this, the effort generated by the use of a seed can be dispensed with in the procedure according to the invention.
• the common chain regulators can be used.
• the use of chain regulators is dispensed with.
• no regulatory substances with transfer constants for viscous nylacetate C s > 100 * 10 "4 ; transfer constants for the polymerization of vinyl acetate to various substances are listed, for example, in” Vinyl Polymerization ", Part I, Ed. GE Ham, Marcel Dekker, New York 1967, Chapter 4.
• Particularly preferred is polymerized in the absence of aldehyde or mercapto regulators.
• the use of chain regulators leads to copolymers which surprisingly have a lower cohesion when used as adhesives.
• the average molecular weight of the vinyl acetate-ethylene copolymers was, as is customary and widespread in industrial practice, by the K value according to Fikentscher (H. Fikentscher, Cellulochemistry 13 (1932) 58; see also W. Philippoff : Viscosity of colloids, published by Theodor Steinkopff, 1942, p. 172), obtained from viscosity measurements in accordance with DIN 51562.
• the K value of the vinyl acetate-ethylene copolymers is generally 65 ⁇ K value ⁇ 130, preferably 75 to 125, more preferably 85 to 125 and in particular 90 to 120.
• the K value according to Fikentscher correlates with the limiting viscosity number [ ⁇ ] Staudinger (see eg PJ Flory, Principles of Polymer Chemistry, Cornell University Press, 1953, p. 308 ff); Accordingly, this amounts to 0.88 ⁇ [ ⁇ ] ⁇ 3.18 dl / g, preferably 1.14 dl / g ⁇ [ ⁇ ] ⁇ 2.96 dl / g, more preferably 1.44 dl / g ⁇ [ ⁇ ] - 2.96 dl / g and in particular 1.60 dl / g ⁇ [ ⁇ ] ⁇ 2.74 dl / g.
• the solvents used according to the invention in particular the alkyl alcohols, have a comparatively small influence on the K value and, as a rule, do not lower it below K values of 90.
• vinyl acetate-ethylene copolymers were obtained which, as or when used in adhesives, lead to an increase in the adhesion even on critical substrates, for example polymer substrates such as polystyrene or polyethylene terephthalate films, in comparison to conventional vinyl acetate-ethylene copolymers and at the same time the cohesion of the adhesive film satisfies the specified minimum requirement of preferably at least 0.2 N / mm 2 , in particular at least 0.5 N / mm 2 , and In some cases significantly higher cohesion values can be achieved and thus cause a property level with high cohesion and high adhesion.
• the proportion of ethylene or vinyl acetate according to the invention in the vinyl acetate-ethylene copolymers has a significant influence on adhesion and cohesion as well as the property level with high cohesion and high adhesion.
• vinyl acetate-ethylene Mischpoly erisaten with lower ethylene content for example, at an ethylene content of ⁇ 18 wt .-%, these properties fall dramatically compared to the results obtained according to the invention.
• solvents such as alkyl alcohol
• the advantageous adhesion and adhesion effects or the property level with high cohesion and high adhesion can be further increased by the distribution of vinyl acetate, ethylene, optionally emulsifier, solvent, especially alkyl alcohol, and protective colloid on initial charge and dosage.
• solvents especially the alkyl alcohols on the initial charge and the metered dose
• the effect of improving the adhesion could in some cases be increased while the cohesion was maintained at a high level.
• the vinyl acetate-ethylene copolymers according to the invention are suitable for use as or in adhesives for the bonding of any substrates, preferably cellulosic materials, such as paper, cardboard, wood, or plastics, such as polyethylene, polyvinyl chloride, polyamide, polyester, polystyrene or acrylonitrile Butadiene styrene.
• the substrates may be, for example, fibers, films or molded parts.
• the adhesives are in particular packaging materials or woven or non-woven fiber materials.
• vinyl acetate-ethylene copolymers as or in adhesives for the bonding of cellulosic substrates, in particular paper, cardboard or cotton fabric, with plastics such as polyethylene, polyvinyl chloride, polyamide, polyester, polystyrene or acrylonitrile-butadiene-styrene, in particular in the form of Kunststoffofffolien, or for the bonding of two plastics together, for example, for film / foil bonding.
• the vinyl acetate-ethylene copolymers are also suitable for other customary applications of such polymers, for example as binders and / or coating agents, in particular for fibrous substances or structures, for example in the area of wovens or preferably nonwovens, as for nonwovens or fabrics.
• the vinyl acetate-ethylene copolymers according to the invention optionally with the addition of further amounts of protective colloids and customary additives, are also suitable for the preparation of water-redispersible polymer powders, in particular by spray drying, and as such, for example, as additives. used in the construction industry for cementitious and non-cementitious applications to improve adhesive properties. It is possible to use the customary processes and apparatus in order to obtain the products of the emulsion polymerization according to the invention by means of
• adhesive films of the vinyl acetate-ethylene copolymers according to the invention preferably show cohesion values, measured as heat resistance, of at least 0.2 N / mm s , preferably of 0.5 N / mm 2, and preferably simultaneously the following high adhesion values, even for difficult to bond substrates:
• Polystyrene film Sidaplay® Polyflex 90 film adhesively bonded to vinyl acetate-ethylene copolymers according to the invention preferably exhibits a peel strength of at least 3.8 N / cm, preferably at least 4 N / cm, and with vinyl acetate according to the invention at a withdrawal speed of 5 mm / min.
• Ethylene copolymers to cotton bonded Polyethelenterephthalat film Hostaphan® RN125 preferably shows a peel strength of at least 3.4 N / cm, preferably at least 4 N / cm or at a take-off speed of 900 mm / min at a take-off speed of 10 mm / min a peel strength of at least 1.2 N / cm, preferably at least 1.5 N / cm.
• a liability sum, HS of preferably at most 18 seconds or less is achieved.
• the aqueous dispersions of the vinyl acetate-ethylene copolymers according to the invention have a high setting speed of the adhesive film which, measured as the starting speed (AZG), reaches values of preferably 3 seconds or less.
• the individual methods, conditions, and materials for determining the cohesive, adhesive, or tensile speed parameters are described in detail below under the heading "Adhesive Properties Testing Methods.”
• the viscosity of the dispersion was measured after tempering to 23 ° C with a Brookfield viscometer, using the optimum for the respective viscosity level spindle at 20 rpm. The viscosity is given in mPas.
• the viscosity values measured for the experimental solids content, FG-EX were values, BF20-EX, to a solids content of 60%: with satisfactory approximation, the following applies to the polymer dispersions investigated here:
• Bf20 (60%) (Bf20-EX) * EXP (0.5 * (60 - (FG-EX))).
• the dispersion was diluted with water.
• the particle size here is the central value of the volume distribution function of the particle diameter x 3 , 5 o in nanometers.
• the determined particle size distributions have essentially monomodal distribution densities whose mode value is close to the central value of the distribution. Results obtained are shown in Table 3.
• Dispersion larger than 40 ⁇ m.
• 100 grams of the dispersion was diluted with up to one liter of distilled water, then passed through a 150 mesh nylon screen cloth, and the passage filtered through a 40 mesh screen mesh. Each was rinsed with water until the passage was clear.
• the residue on the sieve fabrics was weighed back after drying and the sieve residue per sieve fabric, based on dispersion, was calculated. In Table 3, the total residue on both sieves was greater than 40] i.
• a dispersion sample was prepared by weighing into a 50 ml volumetric flask containing 0.5 g of polymer (without polyvinyl alcohol) and 4 g of water. While stirring, tetrahydrofuran (THF) was slowly added dropwise until a clear solution was formed. After tempering to 23 ° C was made up to the calibration mark with THF. The measurement solution had a concentration of 1 g of polymer per 100 ml of solution.
• THF tetrahydrofuran
• the K value is a common and useful measure correlated with the viscometric average molecular weight of the polymer.
• the K value is naturally dependent on the copolymer composition and generally decreases with increasing ethylene content of a vinyl acetate-ethylene copolymer.
• the concentration is in this case in grams per 100 ml of solution, ie in g / dl, ie [ ⁇ ] results here in dl / g.
• the maximum force at break is given as bond strength (cohesion) in N / mm 2 .
• bond strength cohesion
• the mean value of the tests of all 6 test specimens is rounded to one Decimal place specified.
• Cohesion values of at least 0.2 N / mm 8 preferably of at least 0.3 N / mm 2 and in particular of at least 0.5 N / mm 2 are required. Results of the cohesion test are given in Table 4.
• the liability sum was obtained, which can vary between 7 (very good adhesion on all 7 substrates) and 28 (no adhesion on all substrates).
• the liability sum should be ⁇ 18, preferably ⁇ 17.
• Results for the liability sum HS are given in Table 4.
• a Sidaplax® Polyflex 90 film was used as the polystyrene substrate PS and a Hostaphan® N125 film as the polyethylene terephthalate substrate.
• both the cotton fabric and the film were coated with the aqueous dispersion by means of a 100 ⁇ m wire doctor blade.
• the two coated substrates were then manually laminated and pressed using a rubber-coated metal roller (3.5 kg). After bonding, the specimens were each dried for 24 hours under standard conditions (23 ° C. and 50% relative atmospheric humidity).
• the cotton fabric was delaminated from the film in a tensile tester. For this purpose, the non-bonded sections of the strips were clamped and the cotton fabric peeled off at a withdrawal angle of about 180 degrees from the polymer film. The peel tests were carried out the day after drying of the adhesive bond.
• Adh PS adhesion to polystyrene
• a low take-off speed of 10 mm / min slow peeling, Adh PET1
• a high take-off speed of 900 mm / min rapid peeling, Adh PET2
• a 60 mm measuring path was set, whereby the tear propagation resistance between 20 and 60 mm was measured and averaged.
• a measuring path of 150 mm was set, whereby the tear propagation resistance between 20 and 150 mm was measured and averaged.
• the high take-off speed for PET film of 900 mm / min was additionally selected, since at high take-off speed weaknesses with regard to adhesion are particularly clear.
• 8 bonds were delaminated.
• the adhesion results from the average tear strength for all strips and the strip width of 2.5 cm in each case and is given in N / cm rounded to one decimal place.
• adhesion values it may be advantageous to achieve the following adhesion values:
• Mowilith® DM132 is a polyvinyl alcohol stabilized vinyl acetate-ethylene copolymer dispersion of Celanese Corp., which is well known in the art.
• Vinnapas® A920 is a stabilized in the presence of polyvinyl alcohol and APEO emulsifier vinyl acetate-ethylene copolymer dispersion of Wacker Chemie AG, which corresponds to the prior art.
• aqueous emulsifier solutions used in the Examples and Comparative Examples are characterized in Table 1 with regard to chemical composition, proportion of solvent, especially of alkyl alcohol, and with respect to concentration of emulsifier active substance.
• Comparative Examples V3 to VII was polymerized without separate addition of solvents, especially alkyl alcohols; amounts of alkyl alcohol of ⁇ 0.04% by weight, based on the total weight of the monomers, which were still present during the polymerization, resulted from corresponding proportions of alkyl alcohol in the polyvinyl alcohol used.
• examples 1 to 26 essentially different proportions of polyvinyl alcohol and different amounts of anionic sulfosuccinic acid esters of general formula I used according to the invention and of inventive solvent, especially alkyl alcohol, were used for the polymerization; Furthermore, the monomers vinyl acetate and ethylene, the sulfosuccinic acid ester used and the alkyl alcohol used were distributed in different proportions to the reactor charge and the dosage.
• Example 19 alternatively contained a nonionic emulsifier. The following general polymerization instructions were used to prepare the polymer dispersions. Table 2 contains the details of the variations of this process in the individual examples.
• the aqueous preparation was prepared, consisting of
• the pH of the aqueous receiver was controlled and usually adjusted by addition of phosphoric acid or formic acid to pH 3.5 ⁇ 0.1 (recipe amount 10 g).
• the final solids content of the dispersion may be smaller than the formulated solids content;
• deviations between the directive quantities and the Actual quantities for pH adjustments lead to deviations between experimental final solids (FG-Ex) and recipe solids (FG-R).
• the product was cooled to about 30 ° C and the reactor contents were depressurized. With the addition of 10% strength by weight sodium hydroxide solution (recipe amount 5 g), the pH was adjusted to about 5.5. If solids values of ⁇ 62% were determined (with an early end of the reaction), the product was diluted to about 60 to 60.5% solids content while adding water.
• dosage 1 with a 2% by weight hydrogen peroxide solution and as dosage 2 with a 9% strength by weight Na formaldehyde sulfoxylate solution (Brüggolit®) were used.
• the amount of feed water was determined by the concentration of the protective colloid solution used, the recipe solids, and the reactor at the end of the reaction, which - without taking into account the sampling - usually set between 90 and 96 vol .-% was.
• the total amount of monomer used in the template and doses was 1100 grams for all examples.
• Solvents especially alkyl alcohol (s), in particular ethanol or 2-propanol, were added according to their content in the emulsifier samples according to Table 1 and the emulsifier portion chosen for the polymerization introduced into the template and dosage 4; additional proportions of alkyl alcohol were used as ethanol proportional to the emulsifier content in the initial charge and dosage 4, or, regardless of the emulsifier content, only in dosage 4: For Examples 2, 5, 6, and 7, 5 was only the one corresponding to the respective emulsifier patterns 1 introduced alkyl alcohol present during the polymerization.
• alkyl alcohol s
• 2-propanol solvents
• the respective emulsifier patterns were diluted with addition of water and ethanol to 25% by weight emulsifier active substance each time and subdivided to give and dosage 4, so that the values shown in Table 2 for the emulsifier portion (columns 9 and 10) and alkyl alcohol portion (columns 7 and 8) resulted.
• Table 2 summarizes the recipe data. As illustrated by the data in Table 2, for proportions of polyvinyl alcohol based on total monomer was 2.5; 3.0 and 3.5% by weight of the ethylene Part between 19 wt .-% and 32 wt .-% varied wherein between 40 and 100% of the ethylene and 15% to 50% of the vinyl acetate were initially charged in the reactor.
• the emulsifier content based on the total monomer was varied between 0% by weight for the emulsifier-free examples and comparative examples and 3.5% by weight, with between 65% and 100% of the emulsifier being initially charged.
• the proportion of anionic emulsifiers according to the invention was between 1.4 and 3.5% by weight and the proportion of alkyl alcohol between 0.2 and 5.0% by weight, based in each case on the total monomer amount, varied.
• the proportion of solvent used according to the invention, especially alkyl alcohol, in the original varied between 0 and 100% by weight, based on the amount of alkyl alcohol used.
• the polymerizations were carried out at temperatures between 50 ° C and 70 ° C reaction temperature, while the reaction mixture was stirred, so that homogeneity of the reaction mixture and heat dissipation was ensured. For this purpose, speeds between 500 and 600 rpm were sufficient in the 2 liter reactor. The setpoint speed was not changed during the reaction. The desired temperature at the beginning of doses 1 and 2 can be lowered to 30 ° C to 40 ° C and the heat of reaction used to further heat the reaction mixture. It was found that the temperature profile of the polymerization in the specified range has no significant influence on the adhesive properties of the products.
• the recipe is given the emulsifier-free comparative example V4:
• the ethylene content of the vinyl acetate-ethylene copolymers was varied between 19 and 31% by weight and polymerized in the substantial absence of solvent.
• Adh-PET2 adhesion to polyester substrate on fast stripping
• HS adhesion enhancement
• Example 1 satisfies all the adhesive properties requirements and achieves high cohesion and high adhesion property levels.
• Examples 2 and 3 are based on Comparative Example C5 without emulsifier and alkyl alcohol.
• Examples 4, 5, 7, 9, 10 and 11 are based on comparative example V4, which is carried out without emulsifier and alkyl alcohol.
• Example 6 is based on Comparative Example V6 carried out without emulsifier and alkyl alcohol, and
• Example 8 is based on Comparative Example C3 without emulsifier and alkyl alcohol.
• Example 19 is also based on Comparative Example C4. It demonstrates the significant improvement in the adhesion values as a result of the use according to the invention of proportions of solvent, especially alkyl alcohol, in the presence of a nonionic emulsifier.
• Examples 20 to 26 demonstrate the achievement of high adhesion values Adh. PS, Adh-PETl and Adh-PET2 sometimes well above the required minimum values and simultaneously high cohesion values, without falling below the required minimum value, according to the invention using different amounts of solvent, especially alkyl alcohol, in its different distribution on template and dosage.
• solvent, especially alkyl alcohol was added only to Dose 4, for Examples 22 to 26, alkyl alcohol was dispensed between initial and dosage.
• Alkyl alcohol% indicates the proportion of alkyl alcohol in the emulsifier pattern in% by weight, based on the amount of emulsifier;
• Conc% indicates the proportion of emulsifier active substance in the emulsifier pattern in% by weight, based on the amount of the emulsifier pattern;
• Example Example number, V marked comparative example
• VAC-V% proportion of vinyl acetate in the original, based on total vinyl acetate, in% by weight
• alkyl alcohol% proportion of alkyl alcohol in wt .-%, based on total monomer
• alkyl alcohol% by volume proportion of alkyl alcohol in the initial charge in% by weight, based on the total amount of alkyl alcohol;
• Example Example number, V marked comparative example
• Example Example number, V marked comparative example
• Adh PS Adhesion / peel strength in N / cm on polystyrene

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• Adhesives Or Adhesive Processes (AREA)
• Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
• Treatments For Attaching Organic Compounds To Fibrous Goods (AREA)
• Polymerisation Methods In General (AREA)

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  • 2011-07-25 WO PCT/EP2011/062705 patent/WO2012016869A1/de active Application Filing
  • 2011-07-25 CN CN2011800478253A patent/CN103140514A/zh active Pending
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