DE102005023405B4 - Grafted polyvinyl acetals - Google Patents

Abstract

graft of polyvinyl acetals available by polymerization of ethylenically unsaturated monomers in the presence of polyvinyl acetals with unsaturated Acetal.

Description

The This invention relates to grafted polyvinyl acetals, to methods of preparation of grafted polyvinyl acetals and their use.

The Preparation of polyvinyl acetals derived from the corresponding polyvinyl alcohols by polymer-analogous reaction with the corresponding aldehydes to be obtained, has been known since 1924, being in the aftermath a variety of aldehydes for the preparation of the corresponding polyvinyl acetals have been used. Polyvinyl acetals are used in a 3-stage process (polyvinyl acetate → polyvinyl alcohol → polyvinyl acetal) producing products resulting in addition to vinyl acetal groups still contain vinyl alcohol and vinyl acetate units. commercial Polyvinylformal, Polyvinylacetacetal and Polyvinyl butyral (PVB) obtained.

Of the largest scope for polyvinyl acetals is the manufacture of safety glass in the automotive industry and in architecture, using plasticized polyvinyl butyral films as Intermediate layer can be used in glass panes. Another one Field of application for Polyvinyl butyral is the use in anti-corrosive Coatings. Partly because of its good pigment binding power Polyvinyl butyrals are also used as binders in paints and especially used in printing inks. In this application will be the requirement posed that the organic solutions the polyvinyl butyrals as possible have low solution viscosity should, so that colors with high solids content as possible To be able to produce high binder content.

To meet the requirements of the applications mentioned, the polyvinyl acetals are frequently modified. Examples of modified polyvinyl butyrals in the pane film are those in the EP-A 368832 described with sulfonate, carboxylate and phosphate-functional acetal units, which are characterized by improved block and flow behavior.

Examples of modified polyvinyl acetals in the field of corrosion protection are known from EP-A 1055686 it can be seen where polyvinyl acetals modified with tertiary alkanolamines are used. Examples of the ink range are the modified low viscosity solution polyvinyl butyrals of the DE-A 19641064 which are obtained by acetalization of a copolymer with vinyl alcohol and 1-alkyl-vinyl alcohol units.

The prior art also discloses processes in which polyvinyl acetals are modified by means of graft polymerization. In the EP-A 364939 vinyl acetate is grafted onto polyurethane, the vinyl acetate groups saponified and then acetalized. In the JP-A 2003-213182 It is recommended to use hydroxyethyl methacrylate inkjet inks and styrene-grafted polyvinyl butyral. In the JP-A 2003-096357 is used with styrene grafted polyvinyl butyral. The JP-A 2001-172553 describes the use of polyvinyl butyral grafted with alkyl (meth) acrylates as a binder for ceramic powders. Subject of the JP-A 08-335311 is the use of polyvinyl acetal grafted with a styrene- (meth) acrylate copolymer as a binder in magnetic tapes. In Toncheva VD et al., Eur. Polym. J. Vol. 28, no. 2, 191-198, 1992, polyvinyl acetal is grafted with polyethylene oxide and polydimethylsiloxane.

at This grafting reaction did not affect monomers and polymers grafted modified polyvinyl acetal. As a result, runs the Grafting usually incomplete and rather uncontrolled, so often in large part homopolymer next to Polyvinyl acetal present separately. This leads to significant disadvantages. Examples include demixing and phase separation due to incompatibilities the per se different polymers, resulting in organic solvents for example, for turbidity or even lead to Absitz can. In the previously described in the prior art graft products of Polyvinyl acetals and organic monomers are often misery of different polymers. The products are inhomogeneous and for that many applications unusable. Only if a real grafting and thus a covalent attachment the monomers are carried out on the polyvinyl acetals results a completely new property profile and behavior that can not be achieved with an ordinary "blending".

It It was therefore the task, in a simple and effective way Monomers, and optionally also polymers, to polyvinyl acetals to tie, so that homogeneous grafting products are formed.

Surprisingly, it has been found that polyvinyl acetals which carry unsaturated groups, Äu are very active against grafting reactions with organic monomers. It was found that even a slight modification with double bonds along the side chain is sufficient to ensure almost complete attachment of the monomers or polymers.

object Graft copolymers of polyvinyl acetals can be obtained by means of the invention Polymerization of ethylenically unsaturated monomers in the presence of polyvinyl acetals with unsaturated Acetal.

in the The following are among polyvinyl acetals with unsaturated Acetal units understood those which, in addition to the above three Units vinyl acetate, vinyl alcohol and vinyl acetal or vinylacetal groups, containing one or more unsaturated groups.

Suitable polyvinyl acetals with unsaturated acetal units are known from the DE-A 102004053312 known. These are polyvinylacetals with unsaturated acetal units, obtainable by Ace talisierung of partially saponified or fully saponified vinyl ester polymers with> 50 mol% of vinyl alcohol units with one or more, saturated aliphatic aldehydes, and one or more unsaturated, acyclic, aliphatic aldehydes, wherein the Aldehydes can also be used in the form of their hemiacetals and acetals.

suitable conduct partially hydrolyzed or fully saponified vinyl ester polymers from polymers which contain 50 to 100 mol% of vinyl ester units contain. Suitable vinyl esters are vinyl esters of unbranched or branched carboxylic acids with 1 to 15 carbon atoms. Preference is given to vinyl acetate. In addition to the vinyl ester units can optionally also comprising one or more monomers from the group methacrylic and acrylic acid esters of alcohols having 1 to 15 carbon atoms, olefins, dienes, vinylaromatics and vinyl halides copolymerized. These vinyl ester polymers are commercially available or can be prepared in a known manner by means of polymerization; preferably by bulk polymerization, suspension polymerization or by Polymerization in organic solvents, especially preferred in alcoholic solution. Suitable solvents and regulators are, for example, methanol, ethanol, propanol, isopropanol. The polymerization is refluxed at Temperature of 40 ° C up to 100 ° C performed and by adding common Initiators initiated radically.

The Saponification of the vinyl ester polymers is carried out in a manner known per se For example, by the band or kneader method, in the alkaline or acids with the addition of acid or base. Preferably, the vinyl ester solid resin is in alcohol, for example methanol, adjusting a solids content from 10 to 80 wt .-% added. Called as fully hydrolyzed vinyl ester polymers while those polymers whose degree of hydrolysis ≥ 96 mol% is. Partially hydrolyzed polyvinyl esters are to be understood as meaning with a degree of hydrolysis ≥ 50 Mol% and <96 Mol%. The partially or fully hydrolyzed vinyl ester polymers have preferably a degree of hydrolysis of from 50 mole% to 99.9 mole%, especially preferably from 70 mole% to 99.9 mole%, most preferably from 96 mol% to 99.9 mol%.

Preferred unsaturated, acyclic, aliphatic aldehydes, where the aldehyde function can also be present as hydrate, half or full acetal, can be given by the following structural formula: R ² - [CR ⁴ = CR ⁴ ] _z - {CHR ¹ } _y - (CH ₂ ) _x -CH = O.

In the structural formula, R ^{1 is} a branched, saturated or unsaturated, optionally substituted alkyl radical having 1 to 20 C atoms, which may optionally be interrupted by heteroatoms of the type N, O, S. R ¹ also has the meaning OR ³ , where R ^{3 is} a vinyl, (meth) acrylic, allyl or styryl radical. R ² is H or an alkyl, alkenyl, (meth) acryloyl, (meth) acrylic or styryl radical. R ⁴ may be identical or different and is H or a branched, saturated or unsaturated, optionally substituted alkyl radical having 1 to 20 C atoms, which may optionally be interrupted by heteroatoms of the type N, O, S. x and y describe the number of repeating units of the corresponding building block mentioned above, the sum of these respective building blocks being integers between 0 and 40. z is an integer from 0 to 10, wherein at z = 0 at least one of the radicals R ^{1 is} unsaturated. The arrangement of the structural elements (CH ₂ ) _x , (CHR ¹ ) _y , (CR ⁴ = CR ⁴ ) _z can be distributed in blocks, alternately or statistically along the chain.

Especially preferred aldehydes of the above structural formula are acrolein (2-propenal), Crotonaldeyhyd (2-butenal), 2-ethylhexenal, pentenal, hexenal, heptenal and 3- (meth) acryloyl-butyraldehyde. Most preferred are acrolein and crotonaldehyde.

The unsaturated, acyclic, aliphatic aldehydes are used in mixtures with a or more, saturated, aliphatic aldehydes used to form an unsaturated polyvinylacetal receive. Suitable saturated Aldehydes are those from the group comprising aliphatic aldehydes with 1 to 15 carbon atoms, as well their hydrates, hemiacetals and acetals. Preference is given to formaldehyde, Acetaldehyde, propionaldehyde. Particularly preferred are butyraldehyde or mixtures of butyraldehyde and acetaldehyde.

Of the Proportion of unsaturated Groups amounts in the unsaturated Polyvinyl acetals to a value of 0.01 to 60 wt .-%, especially preferably from 0.1 to 40% by weight, and most preferably from 0.5 to 20 wt .-%, based on the total weight of the unsaturated Polyvinyl acetal. The unsaturated polyvinyl acetals used have between 0.001 and 20 mmol / g polymer double bonds. Prefers is a set of double bonds that range between 0.01 and 5 mmol / g polymer moves. The total degree of acetalization of the unsaturated Polyvinyl acetals is 1 to 80 mole%, in the preferred ranges 1 to 25 mole% and 40 to 80 mol%. The viscosity the unsaturated one Polyvinyl acetals (DIN 53015, Höppler method, 10% solution in Ethanol) 4 mPas to 1200 mPas, preferably 4 to 120 mPas.

suitable ethylenically unsaturated Monomers which are based on the unsaturated Polyvinyl acetals can be grafted, are those with a or more ethylenically unsaturated Structural units. Preferably one or more monomers from the Group comprising vinyl esters of unbranched or branched alkylcarboxylic acids with 1 to 15 carbon atoms, (meth) acrylic acid ester of alcohols having 1 to 15 carbon atoms, (meth) acrylamides, vinylaromatics, Olefins, dienes, vinyl halides, vinyl ketones, vinyl ethers, polymerizable silanes, unsaturated Mono- and dicarboxylic acids or their salts, ethylenically unsaturated carboxylic acid amides and -nitriles, mono- and diesters of fumaric and maleic acid, ethylenic unsaturated sulfonic acids or salts thereof, ethylenically unsaturated phosphorus-containing monomers, cationic monomers and silicone macromers.

Suitable vinyl esters are vinyl esters of unbranched or branched carboxylic acids having 1 to 15 carbon atoms. Preferred vinyl esters are vinyl acetate, vinyl propionate, vinyl butyrate, vinyl 2-ethylhexanoate, vinyl laurate, 1-methylvinyl acetate, vinyl pivalate and vinyl esters of α-branched monocarboxylic acids having 5 to 13 carbon atoms, for example VeoVa9 ^R or VeoVa10 ^R (trade names of Resolution Performance Products). Particularly preferred is vinyl acetate.

suitable Monomers from the group of esters of acrylic acid or methacrylic acid are Esters of unbranched or branched alcohols with 1 to 15 C-atoms. Preferred methacrylic acid esters or acrylic acid ester are methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, Propyl acrylate, propyl methacrylate, n-, iso- and t-butyl acrylate, n-, iso- and t-butyl methacrylate, 2-ethylhexyl acrylate, norbornyl acrylate. Especially preferred are methyl acrylate, methyl methacrylate, n-, iso- and t-butyl acrylate, 2-ethylhexyl acrylate and norbornyl acrylate.

suitable Dienes are 1,3-butadiene and isoprene. Examples of copolymerizable olefins are ethene and propene. As vinyl aromatics, styrene and vinyl toluene be copolymerized. From the group of vinyl halides are usually Vinyl chloride, vinylidene chloride or vinyl fluoride, preferably vinyl chloride used.

suitable ethylenically unsaturated Mono- and dicarboxylic acids or their salts are, for example, crotonic acid, itaconic acid, acrylic acid, methacrylic acid, fumaric acid and Maleic acid. Suitable ethylenically unsaturated carboxamides and nitriles are acrylamide and acrylonitrile. As mono- and diesters of fumaric acid and maleic acid can Diethyl and diisopropyl ester and maleic anhydride can be used. ethylenically unsaturated sulfonic acids and their salts are preferably vinylsulfonic acid and 2-acrylamido-2-methylpropanesulfonic acid. When ethylenically unsaturated Phosphorus-containing monomer can be used vinylphosphonate. As cationic monomers are diallyldimethylammonium chloride (DADMAC), 3-trimethylammoniumpropyl (meth) acrylamide chloride (MAPTAC) and 2-trimethylammoniumethyl (meth) acrylate chloride used.

Suitable polymerisable silanes are γ-acrylo- and γ-methacryloxypropyltri (alkoxy) silanes, α-methacryloxymethyltri (alkoxy) silanes, γ-methacryloxypropyl-methyldi (alkoxy) silanes, vinylalkyldi (alkoxy) silanes and vinyltri (alkoxy) silanes, where as alkoxy groups For example, methoxy, ethoxy, methoxyethylene, ethoxyethylene, Methoxypropylenglykolether- or Ethoxypropylenglykolether residues can be used. Examples of these are vinyltrimethoxysilane, vinyltriethoxysilane, vinyltripropoxysilane, vinyltriisopropoxysilane, vinyltris (1-methoxy) isopropoxysilane, vinyltributoxysilane, vinyltriacetoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, methacryloxymethyltrimethoxysilane, 3-methacryloxypro pyltris (2-methoxyethoxy) silane, vinyltrichlorosilane, vinylmethyldichlorosilane, vinyltris (2-methoxyethoxy) silane, trisacetoxyvinylsilane, 3- (triethoxysilyl) propylsuccinic anhydride silane.

Further for the Grafting suitable monomers are functionalized (meth) acrylates and functionalized allyl or vinyl ethers, especially epoxy-functional ones such as glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether, vinyl glycidyl ether, or hydroxyalkyl-functional such as hydroxyethyl (meth) acrylate, or substituted or unsubstituted aminoalkyl (meth) acrylates, or cyclic monomers, such as N-vinylpyrrolidone; or N-vinylformamide or N-vinylacetamide.

Further examples for suitable monomers are pre-crosslinking comonomers such as multiply ethylenic unsaturated Comonomers, for example divinyl adipate, divinylbenzene, diallyl maleate, Allyl methacrylate, butanediol diacrylate or triallyl cyanurate, or post-crosslinking comonomers, for example acrylamidoglycolic acid (AGA), methylacrylamidoglycolic acid methyl ester (MAGME), N-methylolacrylamide (NMA), N-methylolmethacrylamide, N-methylolallylcarbamate, Alkyl ethers such as the isobutoxy ether or ester of N-methylolacrylamide, of N-methylolmethacrylamide and N-methylolallylcarbamate.

For grafting also silicone macromers can be used. These are linear, branched, cyclic and three-dimensionally crosslinked silicones (polysiloxanes) having at least 10 siloxane repeating units and having at least one free-radically polymerizable functional group. Also suitable are the polymerizable silicone macromers, as described in the EP-A 614924 or the silicone macromers with dendrimeric structure described in U.S. Pat EP-A 1095953 are indicated.

Prefers are α, ω-divinyl-polydimethylsiloxanes, α, ω-di- (3-acryloxypropyl) polydimethylsiloxanes, α, ω-di- (3-methacryloxypropyl) polydimethylsiloxanes. When just with unsaturated Groups of substituted silicones are α-monovinyl-polydimethylsiloxanes, α-mono (3-acryloxypropyl) -polydimethylsiloxanes, α-mono (acryloxymethyl) -polydimethylsiloxanes, α-mono- (3-methacryloxypropyl) -polydimethylsiloxanes prefers. Located at the monofunctional polydimethylsiloxanes at the other end of the chain is an alkyl or alkoxy radical, for example a methyl or butyl radical.

Next These organic monomers can additionally with polymers the unsaturated one Polyvinyl acetal are grafted. In addition to the addition polymers, from the above-mentioned organic monomers by free-radical Polymerization can be prepared, for example, vinyl ester homo- and co-polymers, as polymers, for example, polyimines such as polyethyleneimine, Polyethers such as polyglycols or polyethylene oxide, polyamides, polyesters, Polycarbonates, polyurethanes, or even modifications of natural Polymers such as nitrocellulose in question. These can also be with the unsaturated Linked to polyvinyl acetals be, wherein the organic monomers by grafting reactions The link enable.

Consequently can to the unsaturated Polyvinyl acetals also "foreign" polymer chains of others Monomers not obtained by radical polymerization can, but only by anionic or cationic polymerization, polycondensation or polyaddition accessible are about the organic monomers are grafted on. This is only through the activation of the grafting tendency of the polyvinyl acetals the introduction of unsaturated Groups possible.

in the In general, the graft copolymers of polyvinyl acetals a proportion of 0.1 to 99.9 wt .-% polyvinyl acetals with unsaturated Acetal units, and 0.1 to 99.9 wt .-% grafted, ethylenic unsaturated Monomers, in each case based on the total weight of the graft copolymers, and wherein the data in wt .-% added up to 100 wt .-%. In addition to the grafted polymer units, which differ from the ethylenic unsaturated Derived monomers, a proportion of up to 80 wt .-% polymer, based on the total weight of ethylenically unsaturated Monomer and polymer grafted

The Free-radically initiated grafting reaction of the ethylenically unsaturated Monomers and optionally additional Polymers of unsaturated Polyvinyl acetals can basically with all this known polymerization processes, such as bulk polymerization, solution, precipitation, Suspension polymerization in water and emulsion polymerization in water. In the suspension and emulsion polymerization is for example, the unsaturated one Polyvinyl acetal dissolved in organic monomer and fed to the polymerization. Prefers are suspension polymerization and solution polymerization, most preferred is the solution polymerization.

The Polymerization temperature is generally 20 ° C up to 100 ° C, preferably 40 ° C up to 90 ° C. at the copolymerization of gaseous Comonomers such as ethylene, 1,3-butadiene or vinyl chloride can also under pressure, generally between 1 bar and 100 bar worked become. The initiation of the polymerization can with the usual water-soluble or monomer-soluble Initiators or redox initiator combinations take place. Examples for water-soluble initiators are the sodium, potassium and ammonium salts of peroxodisulfuric acid, hydrogen peroxide, t-butyl peroxide, potassium peroxodiphosphate, t-butylperoxopivalate, cumene hydroperoxide, Isopropylbenzene monohydroperoxide, azobisisobutyronitrile. Examples for monomer-soluble initiators are dicetyl peroxydicarbonate, dicyclohexyl peroxydicarbonate, dibenzoyl peroxide, t-butyl perneodecanoate, t-butyl-per-2-ethylhexanoate and t-butyl perpivalate. The initiators mentioned are generally used in an amount of 0.01 to 10.0 wt .-%, preferably 0.1 to 2.0 wt .-%, each based on the total weight of the monomers used. As redox initiators one uses combinations of the mentioned initiators in combination with reducing agents. 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 alkali formaldehyde sulfoxylates, for example, sodium hydroxymethanesulfinate, and ascorbic acid. The Reducing agent amount is generally 0.01 to 10.0 wt .-%, preferably 0.1 to 2.0 wt .-%, respectively based on the total weight of the monomers.

at the solution polymerization become organic solvents such as tetrahydrofuran, diethyl ether, petroleum ether, methyl acetate, Ethyl acetate, methyl ethyl ketone, acetone, isopropanol, propanol, ethanol, methanol, Toluene or benzene or mixtures of these solvents used. Prefers are ethyl acetate, methyl acetate and ethanol. Is the unsaturated polyvinyl acetal, to be grafted on, water-soluble, so water is recommended as a solvent or a mixture of water and a miscible organic Solvent.

at the said method of suspension and emulsion polymerization becomes in the presence of surface-active Substances such as protective colloids and / or emulsifiers polymerized. Suitable protective colloids are, for example, partially hydrolyzed polyvinyl alcohols, Polyvinyl pyrrolidones, polyvinyl acetals, starches, celluloses and their Carboxymethyl, methyl, hydroxyethyl, hydroxypropyl derivatives. Suitable emulsifiers are both anionic, cationic and nonionic emulsifiers, for example anionic surfactants, such as Alkyl sulfates with one chain length from 8 to 18 C atoms, alkyl or alkylaryl ether sulfates having 8 to 18 C atoms in the hydrophobic radical and up to 60 ethylene or propylene oxide units, Alkyl- or Alkylarylsulfonate with 8 to 18 C-atoms, esters and Half ester of sulfosuccinic acid with monohydric alcohols or alkylphenols, or nonionic Surfactants such as alkyl polyglycol ethers or alkylaryl polyglycol ethers with up to 60 ethylene oxide or propylene oxide units.

The Adjustment of the molecular weight and the degree of polymerization is known to the skilled person. This can be done, for example, by adding Regulator, by the solvent content, by varying the initiator concentration and by varying the Temperature done.

The Monomers and optionally additional Polymers that are grafted with can be submitted as a whole, be added in total or be presented in shares and the remainder being added after initiation of the polymerization. The unsaturated ones Polyvinyl acetals to which grafting may also be presented in their entirety will be added in total or presented in shares and the remainder are metered in after initiation of the polymerization.

Prefers is to submit all components and grafting by initiator addition or dosing. Most preferred is the unsaturated Polyvinyl acetals grafted onto, completely submit and to partially introduce the monomers and to dose the remainder. The Dosing times usually amount to 1 to 8 hours, preferably for 2 to 6 hours.

To Completion of the polymerization can Residual monomers and volatile Components by postpolymerization, distillation, passing of inert gas or water vapor or a combination of these measures be removed. For the preparation of water-redispersible Polymer powders can the watery Dispersions, which by means of emulsion and suspension polymerization accessible are, after addition of protective colloids as Verdüsungshilfe in a known manner spray dried become.

The graft copolymers based on polyvinyl acetal with a content of polyvinyl acetal <50 wt .-% are preferably, depending on the polymerization process, in solid form, used as a solution in organic solvents or as a dispersion. They are preferably suitable as binders, in particular in paints, and for the production of adhesives, in particular of heat-sealable coatings and laminating agents. Wei Other fields of application are as base materials for finishes and chewing gum masses. The solid resins are also suitable for the low profile range, in the sound damping area (sound insulation), or as a low shrinking additive.

she can used profitably in the coating or powder coating sector be used, for example, to coat wood, metals, plastics, for example, films, or glass. Also for the textile sector are the Resins best suited. Furthermore, the resins in cosmetics find advantageous use, such as in hairsprays or generally in the hairstyling area. By grafting onto unsaturated polyvinyl acetals the property profile of solid resins is significantly improved for many applications.

Lie in the resin in addition functional groups, for example when using functional Monomers such as glycidyl methacrylate, N-methylolacrylamide, silane-containing Monomers or acrylic acid, the Resins are crosslinked. In this case, the resin itself can crosslink, optionally with the addition of suitable catalysts, or else it can crosslinking mixtures of two different resins are made, for example, one resin has a carboxylic acid function, the other resin has an epoxide function.

With the graft copolymers of the invention based on polyvinyl acetal, with a proportion of polyvinyl acetal ≥ 50 wt .-%, products become accessible, which opposite the hitherto known th conventional polyvinyl acetals have much better properties in many applications. It can the properties and behavior of grafted polyvinyl acetals be varied within a wide range, for example by the Type and amount of monomers, in addition optionally polymers with which the unsaturated polyvinyl acetal is grafted. Depending on the polymerization process are the grafted Polyvinyl acetals in solid form or in the form of an aqueous or organic solution in front. By emulsion polymerization products in the form of a aqueous Dispersion obtained. The grafted polyvinyl acetals are preferred obtained in solid form, as granules, beads, pellets or flakes.

As mentioned in the beginning, There is a need for binders, especially in the printing ink industry with as possible good adhesion to flexible films of different polymers to thus printing inks available to be able to which are very firmly connected to the substrate after application and thus are very difficult to detach from the printed substrate. By grafting on monomers, the adhesion can be significantly improved become.

in the Printing ink area, where polyvinyl acetals used as a binder the interactions with the pigments are of great importance. These interactions can also by the grafting of monomers, and optionally additionally still polymers, on the unsaturated Polyvinyl acetal be influenced extremely favorable depending on the application. So can one for the application of beneficial ink rheology as well over the Binder can be adjusted, such as suitable gloss and transparency.

suitable Ink formulations are known and included in the art in general from 5 to 30% by weight of pigment fraction, for example disazo or phthalocyanine pigments, 5 to 30% by weight of polyvinyl acetal binder and solvents, for example, alcohols such as ethanol or esters such as ethyl acetate.

Possibly can other additives such as retarders, adhesion promoters, plasticizers and other additives such as fillers or waxes be.

Also for laminated safety glass and glass composites and disc foils are the grafted polyvinyl acetals very suitable, in addition to improved adhesion to glass also a higher one Tensile strength can be achieved. The mechanical behavior or the parameters in the melt can be significantly influenced by grafting in the polyvinyl acetals.

Of others serve water-soluble, grafted polyvinyl acetals as protective colloid, for example for aqueous dispersions and in the polymerization in aqueous Medium, and in the preparation of water-redispersible Dispersible polymer powders.

The grafted polyvinyl acetals can furthermore in paints on watery Basis or based on organic solvents. By grafting with "foreign" monomers can also the compatibility increased to other polymers or formulation ingredients or be improved. Another application is the use of grafted polyvinyl acetals in powder coatings.

Further Fields of application of the grafted polyvinyl acetals are the use as a binder in corrosion inhibitors, with the advantage of the better liability is to be mentioned. Next are the grafted polyvinyl acetals also as a binder in the ceramics industry, especially as a binder for ceramic Green body, suitable. To mention is also the use as a binder for ceramic powder and metal powder in injection molding (powder injection molding) and as a binder for the inner coating of cans.

The The following examples serve to further illustrate the invention, without to restrict these in some way:

Preparation of the unsaturated polyvinyl acetals:

Example A:

In In a 6 liter glass reactor, 2690 ml of dist. Water, 1114 ml of a 20% hydrochloric acid (HCl) and 1160 ml of a 20% aqueous solution of a fully saponified polyvinyl alcohol (Viscosity 3.0 mPas; DIN 53015; Method according to Höppler; 4% aqueous solution), submitted. Well was stirring at 10 ° C chilled and at this temperature, 2.5 g of acrolein was added. acrolein was for 30 minutes at 10 ° C pre-reacted with the polyvinyl alcohol, whereby an effective attachment took place. Subsequently was cooled to -1 ° C and There were, within a period of 5 minutes, 151.2 g of butyraldehyde added. The internal temperature of the reactor rose to 0.5 ° C. Within short Time was again cooled to -1 ° C. 3 minutes after the addition of butyraldehyde, the initially clear approach was milky cloudy, and already 5 minutes later the product precipitated in a powdered form. After 40 minutes Reaction time at -1 ° C was the Temperature over a period of 105 minutes increased to 25 ° C and this temperature for more Held for 90 minutes. Thereafter, the powdery product was filtered off and while washed with distilled water until the filtrate is neutral responded. Subsequently the drying took place up to a solids content of at least 98%, first at 22 ° C, then at 35 ° C in a vacuum.

An unsaturated polyvinyl butyral containing 19.06% by weight (42.89 mol%) of vinyl alcohol units was obtained (by ¹ H NMR spectroscopy). The vinyl acetate content was 1.28 wt% (1.47 mol%). The butyral content was 78.50 wt% (54.73 mol%) and the acrolein acetal content (unsaturated moiety) was 1.16 wt% (0.91 mol%). The unsaturated polyvinyl butyral thus has 0.092 mmol double bonds / g polymer. The glass transition temperature Tg was found to be 67.5 ° C. The viscosity (DIN 53015, Höppler method, 10% ethanolic solution) was 19.5 mPas.

Example B:

As Example 1 with the difference that 1.0 g of acrolein and 152.7 g of butyraldehyde were used for the acetalization. An unsaturated polyvinyl butyral containing 18.51% by weight (42.00 mol%) of vinyl alcohol units was obtained (by ¹ H NMR spectroscopy). The vinyl acetate content was 1.44 wt% (1.67 mol%). The butyral content was 79.52 wt% (55.91 mol%) and the acrolein acetal content (unsaturated moiety) was 0.53 wt% (0.42 mol%). The unsaturated polyvinyl butyral thus has 0.042 mmol double bonds / g polymer. The glass transition temperature Tg was found to be 67.3 ° C. The viscosity (DIN 53015, Höppler method, 10% ethanolic solution) was 22.6 mPas.

It was found that the double bonds in the unsaturated polyvinyl butyrals were still completely retained even after a longer storage time of 6 months, as proved by ¹ H NMR spectroscopy.

Grafting on polyvinyl acetals:

Example 1:

• Analysen: FG: 99.9%, Viskosität (Höppler, 10%-ige Lösung in Ethylacetat) = 11.7 mPas, Viskosität (Höppler, 10%-ige Lösung in Ethanol) = 20.7 mPas, Glasübergangstemperatur Tg = 65.0°C.

108.34 g of ethyl acetate, 50.02 g of the unsaturated polyvinyl acetal from Example A, 3.33 g of methyl methacrylate (MMA) and 177.85 mg of PPV (t-butyl perpivalate, 75% solution in aliphatics) were placed in a 1 l glass stirrer with anchor stirrer, reflux condenser and metering devices , Subsequently, the original was heated to 70 ° C. at a stirrer speed of 200 rpm. After reaching the internal temperature of 70 ° C., the initiator feed (46.39 g of ethyl acetate and 711.4 mg of PPV) was started at a rate of 8.73 ml / h. Ten minutes after initiator dosing started, the monomer feed (13.34 g of methyl methacrylate) was retracted at a rate of 2.82 ml / hr. The initiator dosage extended over a period of 360 minutes, the monomer dosage took 300 minutes. After the end of both doses was still 60 minutes Postpolymerized at 70 ° C. The resulting polymer solution was then completely concentrated until a polymer melt remained. After cooling to room temperature, a grafted polyvinyl acetal was obtained in the form of a transparent resin.

• Analyzes: FG: 99.9%, viscosity (Hoppler, 10% solution in ethyl acetate) = 11.7 mPas, viscosity (Hoppler, 10% solution in ethanol) = 20.7 mPas, glass transition temperature Tg = 65.0 ° C.

Example 2:

• Analysen: FG: 99.7%, Viskosität (Höppler, 10%-ige Lösung in Ethylacetat) = 10.2 mPas, Viskosität (Höppler, 10%-ige Lösung in Ethanol) = 16.7 mPas, Glasübergangstemperatur Tg = 64.7°C.

The procedure was as in Example 1, but with the difference that was grafted onto the unsaturated polyvinyl acetal of Example B.

• Analyzes: FG: 99.7%, viscosity (Hoppler, 10% solution in ethyl acetate) = 10.2 mPas, viscosity (Hoppler, 10% solution in ethanol) = 16.7 mPas, glass transition temperature Tg = 64.7 ° C.

Example 3:

• Analysen: FG: 99.9%, Viskosität (Höppler, 10%-ige Lösung in Ethylacetat) = 9.0 mPas, Viskosität (Höppler, 10%-ige Lösung in Ethanol) = 28.9 mPas, Glasübergangstemperatur Tg = 65.1°C.

108.34 g of ethyl acetate, 50.02 g of the unsaturated polyvinyl acetal from Example A, 16.67 g of methyl methacrylate (MMA) and 177.85 mg of PPV (t-butyl perpivalate, 75% solution in aliphatics) were initially taken in a 1 l glass stirrer vessel with anchor stirrer, reflux condenser and metering devices , Subsequently, the original was heated to 70 ° C. at a stirrer speed of 200 rpm. After reaching the internal temperature of 70 ° C., the initiator feed (46.39 g of ethyl acetate and 711.4 mg of PPV) was started at a rate of 8.73 ml / h. The initiator dosage extended over a period of 360 minutes. After the end of the dosing, polymerization was continued at 70 ° C. for a further 60 minutes. The resulting polymer solution was then completely concentrated until a polymer melt remained. After cooling to room temperature, a grafted polyvinyl acetal in the form of a transparent resin was obtained.

• Analyzes: FG: 99.9%, viscosity (Hoppler, 10% solution in ethyl acetate) = 9.0 mPas, viscosity (Hoppler, 10% solution in ethanol) = 28.9 mPas, glass transition temperature Tg = 65.1 ° C.

Comparative Example 4

• Analysen: FG: 99.8%, Viskosität (Höppler, 10%-ige Lösung in Ethylacetat) = 13.6 mPas, Viskosität (Höppler, 10%-ige Lösung in Ethanol) = 7.2 mPas, Glasübergangstemperatur Tg = 61.8°C.

The procedure was as in Example 1, but with the difference that was grafted onto a saturated polyvinyl acetal. The commercially available Polyvinylbutyral BL 18 from Wacker Polymer Systems having the composition 18.0% by weight of vinyl alcohol units, 2.0% by weight of vinyl acetate units and 80.0% by weight of butyral units was used.

• Analyzes: FG: 99.8%, viscosity (Hoppler, 10% solution in ethyl acetate) = 13.6 mPas, viscosity (Hoppler, 10% solution in ethanol) = 7.2 mPas, glass transition temperature Tg = 61.8 ° C.

Comparative Example 5:

• Analysen: FG: 99.9%, Viskosität (Höppler, 10%-ige Lösung in Ethylacetat) = 6.2 mPas, Viskosität (Höppler, 10%-ige Lösung in Ethanol) = 12.4 mPas, Glasübergangstemperatur Tg = 62.5°C.

The procedure was as in Example 3, but with the difference that was grafted onto a saturated polyvinyl acetal. The commercially available polyvinyl butyral BL 18 from Wacker Polymer Systems having the composition 18.0% by weight of vinyl alcohol units, 2.0% by weight of vinyl acetate units and 80.0% by weight of butyral units was used.

• Analyzes: FG: 99.9%, viscosity (Hoppler, 10% solution in ethyl acetate) = 6.2 mPas, viscosity (Hoppler, 10% solution in ethanol) = 12.4 mPas, glass transition temperature Tg = 62.5 ° C.

Example 6:

• Analysen: FG: 99.8%, Viskosität (Höppler, 10%-ige Lösung in Ethylacetat) = 10.7 mPas, Viskosität (Höppler, 10%-ige Lösung in Ethanol) = 15.9 mPas, Glasübergangstemperatur Tg = 62.5°C.

The procedure was as in Example 1, with the only difference that vinyl acetate (VAc) (instead of MMA) was used as the monomer.

• Analyzes: FG: 99.8%, viscosity (Hoppler, 10% solution in ethyl acetate) = 10.7 mPas, viscosity (Hoppler, 10% solution in ethanol) = 15.9 mPas, glass transition temperature Tg = 62.5 ° C.

Example 7:

• Analysen: FG: 99.7%, Viskosität (Höppler, 10%-ige Lösung in Ethylacetat) = 8.7 mPas, Viskosität (Höppler, 10%-ige Lösung in Ethanol) = 14.9 mPas, Glasübergangstemperatur Tg = 56.0°C.

The procedure was as in Example 1, but with the difference that was used as the monomer vinyl acetate (VAc) (instead of MMA) and that was grafted onto the unsaturated polyvinyl acetal of Example B.

• Analyzes: FG: 99.7%, viscosity (Hoppler, 10% solution in ethyl acetate) = 8.7 mPas, viscosity (Hoppler, 10% solution in ethanol) = 14.9 mPas, glass transition temperature Tg = 56.0 ° C.

Comparative Example 8

• Analysen: FG: 99.8%, Viskosität (Höppler, 10%-ige Lösung in Ethylacetat) = 7.5 mPas, Viskosität (Höppler, 10%-ige Lösung in Ethanol) = 12.9 mPas, Glasübergangstemperaturen: Tg1 = 34.8°C; Tg2 = 56.7°C.

The procedure was as in Example 7, except that vinyl acetate was grafted onto a saturated polyvinyl acetal. The commercially available polyvinyl butyral BL 18 from Wacker Polymer Systems having the composition 18.0% by weight of vinyl alcohol units, 2.0% by weight of vinyl acetate units and 80.0% by weight of butyral units was used.

• Analyzes: FG: 99.8%, viscosity (Hoppler, 10% solution in ethyl acetate) = 7.5 mPas, viscosity (Hoppler, 10% solution in ethanol) = 12.9 mPas, glass transition temperatures: Tg1 = 34.8 ° C .; Tg2 = 56.7 ° C.

Example 9:

• Analysen: FG: 99.9%, Viskosität (Höppler, 10%-ige Lösung in Ethylacetat) = 11.2 mPas, Viskosität (Höppler, 10%-ige Lösung in Ethanol) = 19.5 mPas, Glasübergangstemperatur Tg = 60.8°C.

The procedure was as in Example 1, except that styrene (instead of MMA) was used as the monomer and that was grafted onto the unsaturated polyvinyl acetal of Example B.

• Analyzes: FG: 99.9%, viscosity (Hoppler, 10% solution in ethyl acetate) = 11.2 mPas, viscosity (Hoppler, 10% solution in ethanol) = 19.5 mPas, glass transition temperature Tg = 60.8 ° C.

Comparative Example 10:

• Analysen: FG: 99.8%, Viskosität (Höppler, 10%-ige Lösung in Ethylacetat) = 9.8 mPas, Viskosität (Höppler, 10%-ige Lösung in Ethanol) = 18.0 mPas, Glasübergangstemperaturen: Tg1 = 66.2°C; Tg2 = 93.7°C.

The procedure was as in Example 9 except with the difference that was grafted onto a saturated polyvinyl acetal. The commercially available polyvinyl butyral BL 18 from Wacker Polymer Systems having the composition 18.0% by weight of vinyl alcohol units, 2.0% by weight of vinyl acetate units and 80.0% by weight of butyral units was used.

• Analyzes: FG: 99.8%, viscosity (Hoppler, 10% solution in ethyl acetate) = 9.8 mPas, viscosity (Hoppler, 10% solution in ethanol) = 18.0 mPas, glass transition temperatures: Tg1 = 66.2 ° C .; Tg2 = 93.7 ° C.

Example 11:

In a 1 liter glass stirrer with anchor stirrer, Reflux condenser and Dosing devices were 108.34 g of ethyl acetate, 50.02 g of the unsaturated Polyvinyl acetal from Example A, 2.00 g of methyl methacrylate (MMA), 6.67 g of polymethyl methacrylate (PMMA, Tg = 105 ° C, Mw = 50,000 g / mol, prepared by radical polymerization in solution) and 177.85 mg of PPV (t-butyl perpivalate, 75% solution in aliphatics). Then the template was added a stirrer speed from 200 rpm to 70 ° C heated. After reaching the internal temperature of 70 ° C was the Initiator dosing (46.39 g of ethyl acetate and 711.4 mg PPV) with a Rate of 8.73 ml / h started. Ten minutes after initiator dosing has started was the monomer (8.00 g of methyl methacrylate) with a Retracted rate of 1.70 ml / h. The initiator dosage extended over a period of 360 minutes, the monomer dosage lasted 300 Minutes.

• Analysen: FG: 99.8%, Viskosität (Höppler, 10%-ige Lösung in Ethylacetat) = 12.9 mPas, Viskosität (Höppler, 10%-ige Lösung in Ethanol) = 25.1 mPas, Glasübergangstemperatur Tg = 67.5°C.

After the end of both doses, polymerization was continued at 70 ° C. for a further 60 minutes. The resulting polymer solution was then completely concentrated until a polymer melt remained. After cooling to room temperature, a grafted polyvinyl acetal in the form of a transparent resin was obtained.

• Analyzes: FG: 99.8%, viscosity (Hoppler, 10% solution in ethyl acetate) = 12.9 mPas, viscosity (Hoppler, 10% solution in ethanol) = 25.1 mPas, glass transition temperature Tg = 67.5 ° C.

Comparative Example 12:

• Analysen: FG: 99.4%, Viskosität (Höppler, 10%-ige Lösung in Ethylacetat) = 10.7 mPas, Viskosität (Höppler, 10%-ige Lösung in Ethanol) = 23.2 mPas, Glasübergangstemperaturen: Tg1 = 66.3°C; Tg2 = 104.3°C (klein).

The procedure was as in Example 11, but with the difference that was grafted onto a saturated polyvinyl acetal. The commercially available polyvinyl butyral BL 18 from Wacker Polymer Systems having the composition 18.0% by weight of vinyl alcohol units, 2.0% by weight of vinyl acetate units and 80.0% by weight of butyral units was used.

• Analyzes: FG: 99.4%, viscosity (Hoppler, 10% solution in ethyl acetate) = 10.7 mPas, viscosity (Hoppler, 10% solution in ethanol) = 23.2 mPas, glass transition temperatures: Tg1 = 66.3 ° C .; Tg2 = 104.3 ° C (small).

Comparative Example 13

(Polymer blend with 75% by weight of PVB and 25% by weight of PMMA) 7.5 g of powdered polyvinyl butyral Pioloform BL 18 from Wacker Polymer Systems and 2.5 g powdered, ground PMMA (Tg = 105 ° C, Mw = 50,000 g / mol, prepared by free-radical polymerization in solution) were blinded to each other.

Example 14:

In a 1 liter glass stirrer with anchor stirrer, Reflux condenser and Dosing devices were 110.81 g of ethyl acetate, 34.11 g of the unsaturated Polyvinyl acetal from Example A, 6.82 g vinyl acetate (VAc) and 181.91 mg PPV (t-butyl perpivalate, 75% solution in aliphatics) submitted. Subsequently the template became at a stirrer speed from 200 rpm to 70 ° C heated. After reaching the internal temperature of 70 ° C, the initiator feed was (47.45 g of ethyl acetate and 727.6 mg of PPV) at a rate of 8.9 ml / h started. Ten minutes after initiator dosing started the monomer dosage (27.29 g vinyl acetate) at a rate of 5.9 retracted ml / h. The initiator dosage extended over one 360 minutes, the monomer dosage took 300 minutes.

• Analysen: FG: 99.8%, Viskosität (Höppler, 10%-ige Lösung in Ethylacetat) = 6.8 mPas, Viskosität (Höppler, 10%-ige Lösung in Ethanol) = 13.6 mPas, Glasübergangstemperatur Tg = 35.0°C.

After the end of both doses, polymerization was continued at 70 ° C. for a further 60 minutes. The resulting polymer solution was then completely concentrated until a polymer melt remained. After cooling to room temperature, a grafted polyvinyl acetal in the form of a transparent resin was obtained.

• Analyzes: FG: 99.8%, viscosity (Hoppler, 10% solution in ethyl acetate) = 6.8 mPas, viscosity (Hoppler, 10% solution in ethanol) = 13.6 mPas, glass transition temperature Tg = 35.0 ° C.

Comparative Example 15

• Analysen: FG: 99.5%, Viskosität (Höppler, 10%-ige Lösung in Ethylacetat) = 4.5 mPas, Viskosität (Höppler, 10%-ige Lösung in Ethanol) = 8.6 mPas, Glasübergangstemperaturen Tg1 = 32.9°C, Tg2 = 54.9°C.

The procedure was as in Example 14, but with the difference that vinyl acetate was grafted onto a saturated polyvinyl acetal. The commercially available polyvinyl butyral BL 18 from Wacker Polymer Systems having the composition 18.0% by weight of vinyl alcohol units, 2.0% by weight of vinyl acetate units and 80.0% by weight of butyral units was used.

• Analyzes: FG: 99.5%, viscosity (Hoppler, 10% solution in ethyl acetate) = 4.5 mPas, viscosity (Hoppler, 10% solution in ethanol) = 8.6 mPas, glass transition temperatures Tg1 = 32.9 ° C, Tg2 = 54.9 ° C.

Application Testing: Solubility in ethanol

When very sensitive and at the same time very simple method to find out whether the graft polymer is homogeneous between polyvinyl acetal and monomer is or the monomer is complete grafting, the determination of the solubility in ethanol (EtOH) serves. However, this method is only for graft polymers with a Polyvinyl acetal content greater than about 50 wt .-% suitable. Some monomers lead to homopolymers that completely insoluble in EtOH, such as MMA and styrene. Only by the effective linking polyvinyl acetal, which is very soluble in EtOH, can be clear and single-phase solutions to be obtained.

This leads to the high sensitivity of the measuring method. Because the less monomer could be grafted to the polyvinyl acetal and not instead is knüpftes Homopolymer formed the stronger Phase separation occurs in ethanolic solution, that is, the solutions are increasingly cloudy. Is grafted with monomers whose homopolymers insoluble in Ethanol, forms with insufficient grafting and attachment insoluble Sediment or Absitz.

For the exam were the graft polymers of the examples and comparative examples 10% dissolved in ethanol.

• Note 1: Absolut klare Lösung (komplett homogen)
• Note 2: Leichte (kolloidale) Trübung, aber noch transparent
• Note 3: Starke (kolloidale) Trübung, minimale Transparenz
• Note 4: Milchige Trübung, keine Transparenz, ggf. minimaler unlöslicher Anteil
• Note 5: Phasenseparation, merklicher ungelöster Anteil, Absitz
• Note 6: komplette Unverträglichkeit, hoher unlöslicher Anteil, starker Absitz (komplette Inhomogenität)

The solutions were assessed as follows (school grading system):

• Grade 1: Absolutely clear solution (completely homogeneous)
• Grade 2: Slight (colloidal) haze, but still transparent
• Grade 3: Strong (colloidal) haze, minimal transparency
• Grade 4: Milky cloudiness, no transparency, if necessary, minimum insoluble fraction
• Grade 5: Phase separation, noticeably unresolved portion, paragraph
• Grade 6: complete incompatibility, high insoluble content, strong Absitz (complete inhomogeneity)

The results of the test are shown in Table 1: Table 1: example Polyvinyl acetal g = saturated u = unsaturated Monomer (wt%) Number of glass stages Tg Solubility in EtOH; grade 1 u MMA (25) 1 1 2 u MMA (25) 1 1-2 3 u MMA (25) 1 1-2 V4 G MMA (25) 1 3 V5 G MMA (25) 1 3-4 6 u VAc (25) 1 1 7 u VAc (25) 1 1-2 V8 G VAc (25) 2 3 9 u Styrene (25) 1 1-2 V10 G Styrene (25) 2 4-5 11 u MMA / PMMA (15/10) 1 2 V12 G MMA / PMMA (15/10) 2 5 V13 G PMMA (25) blend 2 6 14 u VAc (50) 1 2 V15 G VAc (50) 2 4

Table 1 shows the following:
In Examples 1 and 2, MMA was grafted onto polyvinyl acetals having different levels of unsaturated groups. In both cases, a very effective attachment of the monomer occurred, although the polyvinyl acetal in Example 2 has only a relatively small proportion of double bonds. An effective grafting is thus also at a very low content of double bonds in the polyvinyl acetal. In the case of the graft polymers, clear, single-phase and homogeneous solutions (10% strength in EtOH) were always obtained when grafted onto unsaturated polyvinyl acetals.

In Example 3 was MMA with another method (batch mode in contrast for presentation / Dosierfahrweise in Examples 1 and 2) to an unsaturated Polyvinyl acetal grafted. The grafting was also done in this Case completely and resulted in stable, clear and homogeneous solutions in Ethanol. It should be noted here that with the method of the grafting reaction the properties (such as the mechanical behavior) of the Graft polymers can be varied to a great extent.

The Grafting of organic monomer (MMA) is incomplete as soon as one saturated as a graft Polyvinyl acetals used. This is proven by the comparative examples 4 and 5, where once a template / dosing, the other time a Submission procedure for the grafting reaction was used. The solutions showed here - in comparison to Examples 1 to 3 - a clear cloudiness on, what for inhomogeneities speaks.

One An analogous result was obtained when vinyl acetate was used as the monomer for the Grafting. Examples 6 and 7 focused on unsaturated polyvinyl acetals grafted. This resulted in graft polymers, the clear and homogeneous solutions 10% in EtOH. When using saturated Polyvinyl acetals, however, was the grafting of vinyl acetate only incomplete (Comparative Example 8). A very cloudy ethanolic solution was obtained. This inhomogeneity, lack of connection of vinyl acetate to the polyvinyl acetal and the formation of homopolymer (here PVAc) is also reflected in the fact that the graft polymer two glass transition steps Tg has.

In Example 9, styrene was grafted onto an unsaturated polyvinyl acetal. The attachment was again complete, since clear and homogeneous solutions in ethanol were obtained with the graft polymer. Comparative Example 10 shows what happens when instead grafting styrene onto a saturated, conventional polyvinyl acetal. In this case, the attachment is incomplete and it forms a large proportion of homopolymer (polystyrene). Accordingly, very cloudy solutions were obtained in ethanol, with ei niger components did not solve (probably polystyrene) and these settled on the ground. As in Comparative Example 8, two glass transition temperatures Tg were also found in Comparative Example 10, which demonstrates the inhomogeneity of the graft polymer. In the case of the homogeneous graft polymer from Example 9, obtained by grafting onto an unsaturated polyvinyl acetal, only one Tg was found in the same composition and with the same preparation process.

In Example 11 was in addition to monomer (MMA) with already preformed Polymer (PMMA) on an unsaturated Polyvinyl acetal grafted. It found the same result as in Examples 1 to 3 (graft polymers containing 75% by weight of polyvinyl acetal) and 25% by weight of PMMA), that is the attachment of both monomer and Polymer was almost completely. The ethanolic solution was only slightly cloudy, and Surprisingly, it was only one in the graft polymer Tg found.

at analogous grafting to a saturated polyvinyl acetal on the other hand, because of a lack of connection, obtained inhomogeneous graft polymers, the two glass transition stages (comparative example 12). The 10% solutions in ethanol were biphasic, with a significant proportion of undissolved constituents, which settled on the ground. This found the same behavior as in the case of a misery or a mixture of 75 wt .-% polyvinyl acetal and 25 wt% PMMA (Comparative Example 13) where the polymer is PMMA also not linked to the polyvinyl acetal and because of the insolubility of PMMA in ethanol forms a sediment while the polyvinyl acetal forms in Ethanol dissolved becomes.

In Example 14 was 50% by weight vinyl acetate with a template / dosing method to 50% by weight unsaturated Polyvinyl acetal grafted. It resulted in a homogeneous graft polymer with a Tg that dissolved almost completely in ethanol. In the analogous grafting from VAc to a saturated one Polyvinyl acetal (Comparative Example 15) gives a known Result: an inhomogeneous graft polymer with two glass transition stages, which also dissolves inhomogeneously in ethanol (strong turbidity, phase separation).

Claims (23)

Graft copolymers of polyvinyl acetals obtainable by means of Polymerization of ethylenically unsaturated monomers in the presence of polyvinyl acetals with unsaturated Acetal. Graft copolymers of polyvinyl acetals according to claim 1, characterized in that as a graft polyvinyl acetals available, available by acetalization of partially hydrolyzed or fully hydrolyzed vinyl ester polymers with> 50 mol% of vinyl alcohol units with one or more, saturated, aliphatic aldehydes, and one or more unsaturated, acyclic, aliphatic aldehydes or hydrates, hemiacetals and full acetals. Graft copolymers of polyvinyl acetals according to claim 1 or 2, characterized in that the unsaturated acetal derived from aldehydes, the general formula R ² - [CR ⁴ = CR ⁴ ] _z - {CHR ¹ } _y - (CH ₂ ) _x - CH = O, wherein R ^{1 is} a branched, saturated or unsaturated, optionally substituted alkyl radical having 1 to 20 C atoms, which may be interrupted by heteroatoms of the type N, O, S optionally, or R ^{1 is} OR ³ , wherein R ^{3 is} a vinyl, (meth) acrylic, allyl or styryl radical, and R ^{2 is} H or an alkyl, alkenyl, (meth) acryloyl, (meth) acrylic or styryl radical, and R ^{4 may be the} same or different, and is H or a branched, saturated or unsaturated, optionally substituted, alkyl radical having 1 to 20 C atoms, which may be interrupted by heteroatoms of the type N, O, S, is, and x and y are each 0 to 40, the sum of x + y ≤ 40, and z = 0 to 10. Polyvinyl acetals with unsaturated acetal units according to Claim 3, characterized in that the unsaturated Derive acetal units from aldehydes, from the group comprising Acrolein, crotonone deyhyd, 2-ethylhexenal, pentenal, hexenal, heptenal and 3- (meth) acryloyl-butyraldehyde. Graft copolymers of polyvinyl acetals with unsaturated Acetal units according to claim 1 to 4, characterized in that in addition to the unsaturated Acetal units still saturated Acetal units are included, which are derived from saturated Aldehydes from the group comprising aliphatic aldehydes with 1 to 15 C atoms. Graft copolymers of polyvinyl acetals with unsaturated acetal units according to claim 1 to 5, characterized in that the proportion of acetal units which carry unsaturated groups is from 0.01 to 60 wt .-%, based on the total weight of the saturated acetal units and unsaturated acetalein units. Graft copolymers of polyvinyl acetals with unsaturated Acetal units according to Claims 1 to 6 having a degree of acetalization from 1 to 80 mol%. Graft copolymers of polyvinyl acetals with unsaturated Acetal units according to claim 1 to 7, characterized in that the used unsaturated Polyvinyl acetals of 0.001 to 20 mmol / g polymer double bonds exhibit. Graft copolymers of polyvinyl acetals with unsaturated Acetal units according to claim 1 to 8, characterized in that one or more monomers grafted are included in the group Vinyl esters of unbranched or branched alkylcarboxylic acids with 1 to 15 carbon atoms, (Meth) acrylic esters of Alcohols having 1 to 15 carbon atoms, (meth) acrylamides, vinyl aromatics, Olefins, dienes, vinyl halides, vinyl ketones, vinyl ethers, polymerisable Silanes, unsaturated Mono- and dicarboxylic acids or their salts, ethylenically unsaturated carboxylic acid amides and -nitriles, mono- and diesters of fumaric and maleic acid, ethylenic unsaturated sulfonic acids or salts thereof, ethylenically unsaturated phosphorus-containing monomers, cationic monomers and silicone macromers. Graft copolymers of polyvinyl acetals with unsaturated Acetal units according to claim 1 to 9, characterized in that in addition to the ethylenically unsaturated Additional monomers still polymers on the unsaturated Polyvinyl acetal are grafted. Graft copolymers of polyvinyl acetals with unsaturated Acetal units according to Claims 1 to 10, characterized the graft copolymers have a proportion of 0.1 to 99.9% by weight Polyvinyl acetals with unsaturated Acetal units, and 0.1 to 99.9 wt .-% grafted, ethylenic unsaturated Monomers, in each case based on the total weight of the graft copolymers, contain. Process for the preparation of the graft copolymers of polyvinyl acetals with unsaturated Acetal units according to claim 1 to 11 by mass polymerization, solution, Precipitation polymerization, suspension polymerization in water or emulsion polymerization in water. Method according to claim 12, characterized in that that the polyvinylacetals with unsaturated acetal units complete be submitted and the monomers are partially submitted and the remainder is added. Use of the graft copolymers of polyvinyl acetals with unsaturated Acetal units according to claim 1 to 11 as a binder in printing inks and corrosion inhibitors. Use of the graft copolymers of polyvinyl acetals with unsaturated Acetal units according to claim 1 to 11 as a binder in the ceramic industry. Use of the graft copolymers of polyvinyl acetals with unsaturated Acetal units according to claim 1 to 11 as a binder for ceramic powder and metal powder by injection molding. Use of the graft copolymers of polyvinyl acetals with unsaturated Acetal units according to claim 1 to 11 as a binder for the inner coating of cans. Use of the graft copolymers of polyvinyl acetals with unsaturated Acetal units according to claims 1 to 11 in laminated safety glass, Glass composites and disc foils. Use of the graft copolymers of polyvinyl acetals with unsaturated Acetal units according to Claims 1 to 11 as binders in paints, Laminating agents and adhesives. Use of the graft copolymers of polyvinyl acetals with unsaturated Acetal units according to claims 1 to 11 as bases for seasonings and chewing gum masses. Use of the graft copolymers of polyvinyl acetals with unsaturated Acetal units according to claim 1 to 11 in the low profile range, in Sound Damping area or as Low Shrinkage additive. Use of the graft copolymers of polyvinyl acetals with unsaturated acetal units according to claim 1 to 11 in the coating or powder coating area. Use of the graft copolymers of polyvinyl acetals with unsaturated Acetal units according to claim 1 to 11 in cosmetics.