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
  • C08F214/00—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 a halogen
  • C08F214/02—Monomers containing chlorine
  • C08F214/04—Monomers containing two carbon atoms
  • C08F214/06—Vinyl chloride
• • 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
  • C08F14/00—Homopolymers and 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 a halogen
  • C08F14/02—Monomers containing chlorine
  • C08F14/04—Monomers containing two carbon atoms
  • C08F14/06—Vinyl chloride
• • 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
  • C08F2/18—Suspension polymerisation
  • C08F2/20—Suspension polymerisation with the aid of macromolecular dispersing agents

Definitions

• the present invention relates to an improved process for the preparation of aqueous polymer dispersions stabilized by protective colloid, in particular by polyvinyl alcohol (PVAL), by single-stage radical polymerization of vinyl halides and / or vinyl alkanoates, optionally together with up to 50% by weight of other ethylenically unsaturated compounds copolymerizable therewith.
• protective colloid in particular by polyvinyl alcohol (PVAL)
• PVAL polyvinyl alcohol
• this new process can also be used to prepare dispersions of ethylene-containing polymers which also contain contents of more than 10% by weight, even more than 15% by weight. % and also more than 20% by weight of ethylene units in the polymer still have a high rate of attraction and are therefore also very suitable as adhesives.
• the invention relates to a process for the preparation of aqueous polymer dispersions which are stabilized by protective colloid, preferably only by protective colloid in the production, with contents of 20 to 75, preferably 20 to 70, in particular 30 to 50% by weight on total weight, by single-stage polymerization of vinyl halides, preferably vinyl chloride, and / or vinyl alkanoates, preferably vinyl acetate, optionally together with at most 50 percent by weight, based on the total weight of the monomers liquid under the reaction conditions, of other ethylenically unsaturated compounds copolymerizable therewith at temperatures from 0 to 120 ° C, preferably 20 to 100 ° C, and pressures up to 200 bar by means of at least partially water-soluble radical initiator systems and, if appropriate, in the presence of customary additives.
• the process is characterized in that with the dosing of protective colloid, preferably at least one PVAL with a degree of hydrolysis of 70 to 99.8 mol% and an average degree of polymerization of 200 to 3000, as the first dispersing agent only after a conversion of 1 to 60% by weight .-%, preferably 2 to 25 wt .-%, based on the total weight of the monomers liquid under the reaction conditions, is started.
• protective colloid preferably at least one PVAL with a degree of hydrolysis of 70 to 99.8 mol% and an average degree of polymerization of 200 to 3000
• the remaining amount of these monomers ie 60 to 99% by weight, or in particular 70 to 95% by weight, are. metered in the course of the polymerization, preferably in proportion to their consumption. It has proven to be advantageous in many cases to keep the concentration of these monomers in the reaction mixture approximately at the level which has been submitted until the metering has ended, for. B. 0.2 and 30, preferably 1 to 21, in particular 1.5 to 18 wt .-% (based on total weight of the reaction mixture). But it is of course possible to deviate from it, e.g. B. if special effects are to be achieved.
• “monomers which are liquid under the reaction conditions” are understood to mean those ethylenically unsaturated polymerizable compounds which can be liquefied in the range from 0 to 120 ° C. and up to 200 bar or are ready-to-use liquids.
• examples include primarily the vinyl halides, such as vinyl fluoride, vinyl bromide, preferably vinyl chloride, and the vinyl alkanoates (vinyl esters of saturated straight-chain or branched-chain carboxylic acids, preferably having up to 20 carbon atoms), such as vinyl formate, propionate, butyrate,
• the sum of these monomers is at least 50% by weight, preferably at least 80% by weight. -% of the total amount of the monomers liquid under the given reaction conditions.
• the vinyl chloride and vinyl acetate mentioned, and also one or more of the other vinyl halides and / or alkanoates up to 20% by weight, particularly preferably, such monomers can also be used:
• Mono- and dialkyl, glycidyl and hydroxyalkyl esters of ethylenically unsaturated mono- and dicarboxylic acids e.g. B. esters of (meth) acrylic acid, maleic acid, fumaric acid, crotonic acid and itaconic acid with (un) branched C 1 - to C 20 -alkanols, such as methanol, ethanol, n- and iso-propanol, n-, sec.- and tert.-butanol,
• Polyalcohols such as ethylene, propylene and butylene glycol and pentaerythritol;
• Vinylidene halides such as vinylidene chloride
• ethylenically unsaturated mono- and dicarboxylic acids their anhydrides, their amides and their N-methylolamides etherified with (poly) alkoxyl groups (ethoxyl or propoxyl groups), e.g. B. (meth) acrylic acid, (meth) acrylamide, N-methylol (meth) acrylamide, maleic anhydride, crotonic acid, crotonic acid amides;
• Vinyl derivatives of heterocyclic compounds e.g. B. N-vinyl pyridine and N-vinyl pyrrolidone;
• ⁇ -olefins e.g. B. propylene, butylene, octene, dodecene.
• Monomers with strongly polar groups e.g. B. vinyl sulfonate, the carboxylic acids, amides and anhydrides should preferably be used in total only 5% by weight, in particular 2% by weight, based on the monomers under the reaction conditions.
• Di- and polyvinyl and allyl compounds of di- and polycarboxylic acids and phenols as well as vinyl and allyl (meth) acrylate and / or crotonate can be used in amounts of 0 to 2, preferably up to 0.5% by weight, based on the liquid monomers are copolymerized.
• the monomers from the groups mentioned can be added or metered into the reaction vessel individually or as premixes, and after the start of metering * as a pre-emulsion. It is possible to introduce some or all of these monomers in whole or in part and to meter in the rest. For the sake of simplicity, it is often preferred to premix the desired monomers from the group mentioned and to use them as a mixture and thus to keep the composition of this monomer phase largely constant over the course of the reaction for a relatively long time.
• ethylene is also used as a comonomer in a further preferred embodiment of the process according to the invention.
• the reaction vessel is charged with ethylene up to a partial pressure of 200 bar, preferably up to 80 bar, before or during the reaction.
• This loading is preferably carried out before the reaction, so that the liquid reaction mixture can dissolve part of the ethylene up to the equilibrium of the gas space with the liquid phase.
• the ethylene can be added once, or its partial pressure can last for a long time, in particular until the end of the metering of the monomers which are liquid under the reaction conditions are kept largely constant by subsequent metering.
• the particle size distribution of the resulting dispersions can be controlled in a simple manner by the time and the amount of the protective colloid being added for the first time.
• the polymerization rate can be increased, since the lower viscosity allows the heat of reaction to be dissipated more quickly.
• This lower viscosity of dispersions produced according to the invention, even with high levels, is particularly surprising since it is known that the viscosity can be increased by adding protective colloid to aqueous dispersions.
• Another advantage of the method according to the invention is that in the preferred use of dispersions prepared according to the invention for the production of redispersible powders, e.g. B. for use in Construction sector as an adhesive or additive to hydraulically setting compositions, because of the lower grafting of the protective colloid, in particular the polyvinyl alcohol (PVAL), there is more free protective colloid at the end of the polymerization. This at least partially eliminates the need to add the protective colloid, in particular PVAL, during or after drying.
• PVAL polyvinyl alcohol
• the protective colloids used are those which are generally customary for the polymerization, for.
• At least one polyvinyl alcohol with a degree of hydrolysis of from 70 to 99.8 mol% (corresponding to the saponification number from approx. 10 to approx. 257) is preferred, preferably 74 to 99.5 mol% (corresponding to the saponification number from approx. 20 to approx. 240) ) and with an average degree of polymerization of 200 to 3000 (corresponding to an approximate Höppler viscosity of a 4% by weight aqueous solution at 20 ° C. of approx. 3 to approx.
• the protective colloid in particular the PVAL, is used in a total amount of 0.5 to 15% by weight, preferably 3 to 10% by weight, based on the monomers which are liquid under the reaction conditions. If comonomers are additionally used which are known to stabilize dispersion (e.g. vinyl sulfonate), z. B. even the addition of about 1 to 3 wt .-% protective colloid provide very good results.
• the polymerization is preferably carried out by means of so-called redox initiator systems, which generally consist of a combination of at least one peroxidic compound and * reducing agent.
• redox initiator systems which generally consist of a combination of at least one peroxidic compound and * reducing agent.
• One or all of these components can be initially introduced, the other component and optionally the rest of the partially introduced component or optionally both components are then metered in during the polymerization.
• the oxidation component can be introduced and the polymerization is controlled by metering in the reduction component. This is generally the preferred embodiment.
• peroxidic compounds are preferred examples of the oxidation component: Ammonium and potassium persulfate, -peroxodisulfate, hydrogen peroxide, alkyl hydroperoxides, such as tert. -Butyl hydroperoxide, peroxodiphosphates, such as potassium, sodium and ammonium peroxodiphosphate, and mixtures thereof.
• water-soluble sulfites and sulfoxylates such as alkali (Na, K) or ammonium sulfite or hydrogen sulfite or alkali (Na, K) or zinc formaldehyde sulfoxylate.
• Hydrogen / noble metal catalyst components are also suitable as activators with the simultaneous use of small amounts of heavy metal salts.
• Suitable initiator systems are u. a. "Fundamental Principles of Polymerization" G.F. Alelio, John Wiley and Sons Inc.,
• radical initiators e.g. B. the persulfates or peroxodiphosphates in the absence of a reducing agent possible. Both in this system and in the aforementioned, traces of salts of suitable heavy metals, e.g. B.- of iron or copper added.
• anionic and / or nonionic emulsifiers in amounts of 0 to 4% by weight, preferably up to 2% by weight, based on the solids content of the dispersion , are added.
• anionic and / or nonionic emulsifiers in amounts of 0 to 4% by weight, preferably up to 2% by weight, based on the solids content of the dispersion , are added.
• alkali or alkaline earth metal salts of alkylated benzene and naphthalenesulfonic acids such as sodium benzyl sulfonate, alkali alkyl sulfonates, such as, for.
• alkylsulfuric acids such as sodium lauryl sulfate, sodium alkyl
• the process according to the invention is preferably carried out at pH values from 2.5 to 7. However, this range can also be exceeded or undershot if necessary.
• customary buffer substances can also be added, e.g. B. bicarbonates, borates, acetates, citrates, mixtures of primary and secondary phosphates of the alkali metals.
• the process according to the invention is preferably produced by the metering process, but the entire amount of monomers can be introduced.
• at least one monomer can be introduced in whole or in part, while the others are metered in whole, and optionally the rest of the partially introduced monomers.
• the addition of protective colloid is preferred at the earliest when the (easy to determine) solid content of the dispersion of 2 units -%, preferably 5% by weight, and at the latest at a solids content of 40% by weight, more preferably 30% by weight, in particular 20% by weight.
• the dispersions produced by the process according to the invention are suitable as adhesives, for coating paper, fabrics and nonwovens, from natural or synthetic fibers, glass fibers, wood fibers, etc., as additives or as binders in concrete and mortar mixtures.
• the viscosities of the PVALs in mPas were determined by Höppler, those of the dispersions using the Epprecht rheometer, the measuring unit being given in ().
• the pH was kept at 2.5 to 5 by metering in ammonia or formic acid. The remaining amounts of monomer were metered in continuously as in the previous procedure.

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• 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)
• Polymerisation Methods In General (AREA)
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• 1982
  • 1982-07-20 DE DE19823227090 patent/DE3227090A1/de not_active Withdrawn
• 1983
  • 1983-06-09 JP JP58501991A patent/JPS59501363A/ja active Granted
  • 1983-06-09 US US06/518,308 patent/US4528315A/en not_active Expired - Fee Related
  • 1983-06-09 DE DE8383105657T patent/DE3366242D1/de not_active Expired
  • 1983-06-09 EP EP83901919A patent/EP0114834A1/de active Pending
  • 1983-06-09 WO PCT/EP1983/000149 patent/WO1984000369A1/de not_active Ceased
  • 1983-06-09 EP EP83105657A patent/EP0099463B1/de not_active Expired

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