WO2005037877A1 - Compositions containing polyvinylacetal, films and composite glass and method for the production thereof - Google Patents

Abstract

The invention relates to compositions containing at least 10 wt. % of at least one polyvinylacetal in relation to the overall weight of the composition, obtainable by means of a method wherein a polymer (A), which, in relation to the overall weight of said polymer (1) contains 25.5 to 100 wt. % structural units of formula 1, wherein R<1> represents hydrogen or methyl, b) 0 74.5 wt. % structural units of formula (2) R<2> represents hydrogen or an alkyl radical with 1 - 6 carbon atoms, c) 0 -70 wt.- % structural units of formula (3), wherein R<3>,R<4>, R<5> and R<6>, independently from each other respectively represent radicals with a molecular weight ranging from 1-500 g/mol, is reacted with at least one compound (B) of formula (4), wherein R<7> and R<8> are independently from each other respectively represent hydrogen, COOH, COOM, an alkyl group with 1 - 10 carbon atoms or an optionally substituted aryl group with 6 - 12 carbon atoms and wherein M is a metal cation or an optionally alkylated ammonium cation, wherein the polyvinyl acetal contains 25.5 - 50 wt. % structural units of formula (1).

Description

 Compositions, films and laminated glasses containing polyvinyl acetal and processes for their production

The present invention relates to polyvinyl acetal-containing compositions and to films and laminated glasses which have the polyvinylacetal-containing compositions. In addition, the present invention relates to methods for producing these compositions and films.

Polyvinyl acetals, which are usually obtained by acetalization of the corresponding polyvinyl alcohols, have been known for a long time and are thermoplastic processed in large quantities and, in particular, extruded to form foils which, among other things. a. are characterized by excellent mechanical properties and can be used as intermediate layers in laminated glass, preferably for vehicle glass panes, architectural glasses for the construction sector and bulletproof glass panes.

Polyvinyl acetals suitable for use in laminated glasses are described, for example, in WO 02/055595. Such films already have a good property profile, but there is a permanent need to improve the safety properties of a laminated glass.

In view of the prior art, it was therefore an object of the present invention to provide a composition with which laminated glasses can be produced which have particularly excellent safety properties.

Furthermore, the present invention was based on the object of specifying a composition which can be processed easily. In particular the composition should show a low tendency to yellowing when producing polyvinyl acetal films.

It was also an object of the present invention to provide compositions which can be easily manufactured and processed on an industrial scale and inexpensively.

It was also an object of the present invention to provide films for safety glasses which can be easily adapted to the particular needs.

These and other tasks which are not explicitly mentioned, but which can easily be derived or inferred from the contexts discussed herein, are achieved by a composition with all the features of claim 1. Appropriate modifications of the compositions according to the invention are protected in the subclaims which refer back to claim 1 , Furthermore, a method for producing the composition according to the invention is claimed in the method claims. Furthermore, the subordinate product claims 12 and 22 describe particularly advantageous areas of use of the composition according to the invention.

The fact that a polymer (A) which, based on the total weight of the polymer (A), a) comprises 25.5 to 100.0% by weight of structural units of the formula (1)

where R ^{1 is} hydrogen or methyl,

b) 0 to 74.5% by weight of structural units of the formula (2)

worin R² Wasserstoff oder einen Alkylrest mit 1 bis 6 Kohlenstoffatomen darstellt,

in which R ^{2 represents} hydrogen or an alkyl radical having 1 to 6 carbon atoms,

c) 0 to 70.0% by weight of structural units of the formula (3)

worin R³, R⁴, R⁵ und R⁶, jeweils unabhängig voneinander Reste mit einem Molekulargewicht im Bereich von 1 bis 500 g/mol sind, enthält, mit mindestens einer Verbindung (B) der Formel (4),

wherein R ³ , R ⁴ , R ⁵ and R ⁶ , each independently of one another, contain residues with a molecular weight in the range from 1 to 500 g / mol, with at least one compound (B) of the formula (4),

worin R und R jeweils unabhängig voneinander Wasserstoff, COOH, COOM, eine Alkylgruppe mit 1 bis 10 Kohlenstoffatomen oder eine gegebenenfalls substituierte Arylgruppe mit 6 bis 12 Kohlenstoffatomen sind und wobei M ein Metallkation oder ein gegebenenfalls alkyliertes Ammoiuumkation ist, so umsetzt, dass das erhaltene Polyvinylacetal 25,5 bis 50 Gew.-% Struktureinheiten der Formel (1) enthält, werden Zusammensetzungen umfassend mindestens 10 Gew.-% Polyvinylacetale, bezogen auf das Gewicht der Zusammensetzung, zur Verfügung gestellt, mit denen Verbundgläser hergestellt werden können, die besonders hervorragende Sicherheitseigenschaften aufweisen.

wherein R and R are each independently hydrogen, COOH, COOM, an alkyl group having 1 to 10 carbon atoms or an optionally substituted aryl group having 6 to 12 carbon atoms and where M is a metal cation or an optionally alkylated ammonium cation, that the polyvinyl acetal obtained contains 25.5 to 50% by weight of structural units of the formula (1), compositions comprising at least 10% by weight, based on the weight of the composition, of polyvinyl acetals are made available, with which laminated glasses can be produced, which have particularly excellent security properties.

Furthermore, further advantages are achieved by the present invention. These include:

> The compositions according to the invention can be produced inexpensively.

> The compositions of the present invention can easily be protected against yellowing in the course of thermoplastic processing.

> The adhesion properties of the compositions according to the invention and of the films on glass obtainable therefrom can be adjusted over a very wide range. In this way, this property can be perfectly adapted to the special needs of the users.

The polyvinyl acetal can be obtained by reacting at least one polymer (A) with at least one compound (B), the polymer (A) in each case comprising the following structural units, based on its total weight: a) 25.5 to 100.0% by weight, preferably 50.0 to 100.0% by weight, in particular 50.0 to 99.9% by weight, structural units of the formula (1)

b) 0 bis 74,5 Gew.-% Struktureinheiten der Formel (2)

b) 0 to 74.5% by weight of structural units of the formula (2)

c) 0 to 65.0% by weight, preferably 0 to 60.0% by weight, in particular 0.01 to 60.0% by weight, of structural units of the formula (3)

The respective structural units are of course different from one another, in particular in the context of the present invention the structural unit of the formula (3) does not include the structural units of the formula (1) or (2).

The radical R ¹ each independently represents hydrogen or methyl, preferably hydrogen.

The radical R ² denotes hydrogen or an alkyl radical with 1 to 6 carbon atoms, preferably an alkyl radical with 1 to 6 carbon atoms, advantageously a methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl -, tert-butyl, n-pentyl or an n-hexyl group, advantageously a methyl or an ethyl group, in particular a methyl group. The radicals R ³ , R ⁴ , R ⁵ and R ⁶ are each, independently of one another, radicals with a molecular weight in the range from 1 to 500 g / mol, advantageously hydrogen, an optionally branched, aliphatic or cycloaliphatic

Radical having 1 to 16 carbon atoms, which may optionally contain one or more carboxylic acid, carboxylic anhydride, carboxylic ester, carboxamide and / or sulfonic acid groups.

Particularly preferred structural units of the formula (3) are derived from straight-chain or branched olefms having 2 to 18 carbon atoms, (meth) acrylic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid, (meth) acrylamides and or ethylene sulfonic acid. Here, olefins, especially those with a terminal C-C double bond, which preferably have 2 to 6 carbon atoms, in particular ethylene, have proven to be very particularly favorable. Furthermore, structural units (3) which are derived from acrylamidopropenylsulfonic acid (AMPS) also lead to very particularly advantageous results according to the invention.

The total number of structural units of the formula (2) is preferably in the range from 0.01 to 40 mol%, advantageously in the range from 0.05 to 25.0 mol%, in particular in the range from 0.1 to 15.0 mol -%, each based on the total number of structural units of the formula (1) and (2). According to a first preferred embodiment of the present invention, a polymer (A) is used which, based on the total number of structural units of the formula (1) and (2), contains 0.1 to 2.0 mol% of structural units of the formula (2) , According to a second preferred embodiment of the present invention, a polymer (A) is used which, based on the total number of structural units of the formula (1) and (2), contains 3.0 to 7.0 mol% of structural units of the formula (2). According to a third preferred embodiment of the present invention, a polymer (A) is used which, based on the total number of structural units of the formula (1) and (2), contains 10.0 to 15.0 mol% of structural units of the formula (2). According to a further particularly preferred embodiment of the present invention, the polymer (A), based in each case on its total weight, contains greater than 50.0% by weight, advantageously greater than 60.0% by weight, advantageously greater than 70.0% by weight, in particular greater than 80.0% by weight of structural units of the formula (1) and / or (2). Particularly advantageous results can be achieved with polymers (A) which, based in each case on their total weight, are greater than 85.0% by weight, advantageously greater than 90.0% by weight, advantageously greater than 95.0% by weight, contain in particular greater than 99.0% by weight of structural units of the formula (1) and or (2). It has proven to be particularly advantageous according to the invention that the polymer (A) contains more than 95.0% by weight of structural units of the formula (1).

In the context of the present invention, the polymer (A) can have a syndiotactic, isotactic and / or atactic chain structure. Furthermore, it can exist both as a random and as a block copolymer.

The viscosity of the polymer (A) is of minor importance according to the invention; in principle, both low-molecular and high-molecular polymers (A) can be used. Nevertheless, it has proven to be particularly favorable in the context of the present invention that the polymer (A) has a viscosity in the range from 1.0 to 70 mPas, preferably in the range from 2.0 to 40 mPas, in particular in the range from 2. 5 to 35 mPas, (measured as a 4% by weight aqueous solution according to Höppler at 20 ° C, DIN 53015).

The polymers (A) to be used according to the invention can be prepared in a manner known per se in a two-stage process. In a first step, the corresponding vinyl ester is in a suitable solvent, usually water or an alcohol, such as methanol, ethanol, propanol and or Butanol, radical polymerized using a suitable radical initiator. If the polymerization is carried out in the presence of free-radically copolymerizable monomers, the corresponding vinyl ester copolymers are obtained.

The vinyl ester (co) polymer is then saponified in a second step, usually by transesterification with methanol, it being possible to set the degree of saponification in a manner known per se, for example by varying the catalyst concentration, the reaction temperature and / or the reaction time. For further details, reference is made to the current specialist literature, in particular to Ullmann's Encyclopedia of Industrial Chemistry, Fifth Edition on CD-Rom Wiley-VCH, 1997, Keyword: Poly (Vinyl Acetals) and the references cited therein.

According to the invention, the compound (B) satisfies the formula (4)

The radicals R ⁷ and R ⁸ are each independently hydrogen, COOH, COOM, an alkyl group with 1 to 10 carbon atoms or an aryl group with 6 to 12 carbon atoms. These alkyl and aryl radicals can be substituted with one or more carboxyl, hydroxyl, sulfonic acid groups and / or halogen atoms, such as fluorine, chlorine, bromine, iodine. The radical M denotes a metal cation or an optionally alkylated ammonium cation. Particularly favorable metal cations are derived from elements of PSE with an electronegativity less than 2.0, preferably less than 1.5, and include in particular Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ , Be ²⁺ , Mg ²⁺ , Ca ²⁺ , Sr ²⁺ , Ba ²⁺ and Al ³⁺ . To those particularly useful for the purposes of the present invention Ammonium cations include NH ₄ ⁺ , H ₃ NCH ₃ ⁺ , H ₃ NC ₂ H ₅ ⁺ , H ₃ NC ₃ H ₇ ⁺ , H ₃ NC ₄ Hc H ₂ N (CH ₃ ) ₂ ⁺ , H ₂ N (C ₂ H ₅ ) ₂ ⁺ , H ₂ N (C ₃ H ₇ ) ₂ ⁺ , H ₂ N (C ₄ H ₉ ) ₂ ⁺ , HN (CH ₃ ) ₃ ⁺ , HN (C ₂ H ₅ ) ₃ ⁺ , HN (C ₃ H ₇ ) ₃ ⁺ , HN (C ₄ H ₉ ) ₃ ⁺ , N (CH ₃ ) ₄ ⁺ , N (C ₂ H ₅ ) ₄ ⁺ , N (C ₃ H ₇ ) ₄ ⁺ and N (C ₄ H ₉ ) ₄ ⁺ .

Compounds (B) which are particularly preferred for the purposes of the present invention include formaldehyde, acetaldehyde, propionaldehyde, n-butyraldehyde, isobutyraldehyde, 2-ethoxybutyraldehyde, paraldehyde, 1,3,5-trioxane, capronaldehyde, 2-ethylhexanal, pelargonaldehyde, 3,5,5-trimethylhexanal, 2-formylbenzenesulfonic acid, acetone, ethyl methyl ketone, butyl ethyl ketone and / or ethyl hexyl ketone. According to a further preferred embodiment, glyoxylic acid HCO-COOH is used as compound (B).

In the context of the present invention, the use of aldehydes, i. H. of compounds of formula (4) with R = hydrogen and R = hydrogen, a methyl, ethyl, n-propyl or an iso-propyl group, preferably of formaldehyde, acetaldehyde and / or n-butyraldehyde, especially of n-butyraldehyde , especially proven.

The amounts of compound (B) can in principle be chosen arbitrarily in the context of the present invention. Advantageously, between 0.1 and 150 parts by weight, preferably between 10 and 80 parts by weight, particularly preferably between 20 and 70 parts by weight of compound (B), in each case based on 100 parts by weight of polymer (A ), used.

The starting compounds (A) and (B) are preferably reacted in at least one solvent. A particularly useful solvent in this connection is water.

The reaction is also conveniently carried out in the presence of acidic catalysts. Suitable acids include both organic acids such as for example acetic acid as well as mineral acids such as hydrochloric acid, sulfuric acid and / or nitric acid, the use of hydrochloric acid, sulfuric acid and / or nitric acid having proven particularly useful in technology. The reaction is preferably carried out by introducing a mixture of components (A) and (B) in aqueous solution and then adding the acidic catalyst dropwise.

The reaction temperature can be varied over a wide range, but often the temperature is in the range from -20.0 ° C to 100.0 ° C, preferably in the range from 0.0 ° C to 80.0 ° C. The same applies to the pressure at which the implementation is carried out. The reaction can take place both under negative pressure and under positive pressure. However, it is preferably carried out at normal pressure.

Alternative methods of producing the polymers are obvious to the person skilled in the art. For example, instead of compound (B) it is possible to use compounds which release compounds (B) under the chosen reaction conditions. These include a. cyclic trimers of aldehydes and acetals of aldehydes or ketones.

It is essential in the reaction that the polyvinyl acetal obtained contains at least 25.5% by weight, preferably at least 25.8% by weight, of structural units of the formula (1). The polyvinyl acetal obtained contains at most 50% by weight, preferably at most 40% by weight and particularly preferably at most 35% by weight, of structural units of the formula (1).

This proportion can be determined in a generally known manner. This includes spectroscopic and chemical methods. For example, the polyvinyl acetal can be acetylated with an excess of acetic anhydride in pyridine. After the reaction, the excess becomes with water Acetic anhydride hydrolyzed and the resulting acetic acid titrated potentiometrically with sodium hydroxide solution. The PVOH content is calculated based on the consumption of sodium hydroxide solution.

In addition to the use of corresponding molar proportions of the at least two components (A) and (B), the proportion of structural units of the formula (1) can also be achieved by the type, in particular by the duration, of the reaction, since the acetalization reaction is terminated before complete conversion can be.

According to a preferred embodiment of the present invention, the polyvinyl acetal is cross-linked. The crosslinking can be carried out in a manner known per se, for example by reacting remaining hydroxyl groups in the polyvinyl acetal with di- or polyaldehydes. However, it is particularly advantageous to crosslink the polyvinyl acetal by reaction and intermolecular esterification of remaining hydroxyl groups in the polymer with an anacetalized aldehyde carboxylic acid, in particular glyoxylic acid.

In a further preferred embodiment of the present invention, the polyvinyl acetal is not crosslinked and preferably has a weight average molecular weight of less than 1,000,000 g / mol, advantageously less than 500,000 g / mol, in particular less than 200,000 g / mol. The weight average molecular weight can be determined in a manner known per se, for example by means of static light scattering. For the purposes of the present invention, gel permeation chromatography, advantageously using a polyvinyl acetal calibration, has also proven particularly useful.

According to the invention, the composition comprises at least 10% by weight, in particular at least 30% by weight, preferably at least 50% by weight, and particularly preferably at least 70% by weight of polyvinyl acetals, based on the weight of the composition.

According to a particular embodiment of the present invention, the composition can comprise plasticizers, for example to vary the glass transition temperature. In general, the composition has 0 to 50% by weight, preferably 25 to 40% by weight, of plasticizer, based on the weight of the composition, without any intention that this should impose any restriction.

A list of commercially available plasticizers, which contains information about their compatibility with polyvinyl acetals, in particular polyvinyl butyral, can be found, for example, in the publication Modern Plastics Encyclopedia 1981/1982, pp. 710 to 719. Preferred plasticizers are diesters of aliphatic diols, in particular of aliphatic polyether-or polyether polyols, with aliphatic carboxylic acids, preferably diesters of polyalkylene oxides, in particular diesters of di-, tri- and tetraethylene glycol with aliphatic (C ₆ -C ₁ o) -carboxylic acids, preferably 2 Ethyl butyric acid and n-heptanoic acid, he diester of aliphatic or aromatic (C ₂ -C ₈ ) dicarboxylic acids, preferably adipic, sebacic and phthalic acid, with aliphatic (C -Cj) alcohols, preferably dihexyl adipate, phthalates, trimellitates, Phosphates, fatty acid esters, especially triethylene glycol bis (2-ethylbutyrate), aromatic carboxylic acid esters, especially dibenzoates, and / or hydroxycarboxylic acid esters.

Particularly preferred plasticizers are dibenzoates of alkylene and / or polyalkylene glycols, in particular di-, tri- and / or tetraalkylene glycols. Of these, the dibenzoates of the dialkylene glycols are very particularly preferred, the dipropylene glycol dibenzoate to be mentioned in particular. In addition, ethers of alkylene and / or polyalkylene glycols, in particular di-, tri- and / or tetraalkylene glycols, are preferred plasticizers. These include in particular dialkyl ethers of polyethylene glycols, with tetraethylene glycol dimethyl ether being particularly preferred.

In the context of the present invention, the composition can also oxalic acid,. H. a compound of the formula

aufweisen. Hierbei können auch Derivate der Oxalsäure, beispielsweise die Mono- und Diester, insbesondere die Methyl-, Ethyl-, Propyl- und/oder Butylester verwendet werden.

exhibit. Derivatives of oxalic acid, for example the mono- and diesters, in particular the methyl, ethyl, propyl and / or butyl esters, can also be used here.

The content of oxalic acid is generally in the range from 0 to 2% by weight, preferably 0.01 to 1.8% by weight, based on the weight of the composition, without any intention that this should impose a restriction.

According to a further aspect of the present invention, the composition can have antioxidants. In the context of the present invention, antioxidants, sometimes also substances called oxidation inhibitors, preferably refer to organic compounds which inhibit and or prevent undesired changes in the polyvinyl acetal caused by the action of oxygen, inter alia, by oxidative processes. Such connections are well known from the prior art and z. B. in plastics and rubbers (in particular to protect against aging), fats (in particular to protect against rancidity), oils, animal feed, automotive gasoline and jet fuels (in particular to protect against resinification), Transformer and turbine oil (especially to protect against sludge formation), aroma substances (in particular to protect against the formation of undesirable aroma components) and paints (in particular to protect against skin formation).

The effect of the antioxidants is mostly that they act as a radical scavenger for the free radicals that occur during auto-oxidation. For further details, reference is made to the current specialist literature, in particular to the Römpp Lexicon Chemistry; Editor: J. Falbe, M. Regitz; Stuttgart, New York; 10th edition (1996); Keyword "antioxidants" and the literature references cited here.

Antioxidants particularly suitable for the purposes of the present invention include u. a. Tocopherol, tert-butylmetoxyphenol (BHA), butylated hydroxytoluene (BHT), octyl gallate, dodecyl gallate, ascorbic acid, lactic acid, citric acid, tartaric acid, optionally substituted phenols, optionally substituted hydroquinones, optionally substituted quinones, optionally substituted pyrocatechols, optionally substituted aromatic amines, optionally substituted metal complexes of an aromatic amine, optionally substituted triazines, organic sulfides, organic polysulfides, organic dithiocarbamates, organic phosphites and organic phosphonates.

In addition, further preferred antioxidants are described in EP 0 568 999 A1.

According to a particular aspect of the present invention, the composition can comprise a mixture of oxalic acid and at least one antioxidant. The weight ratio of oxalic acid to antioxidant is advantageously in the range from 1:20 to 20: 1, advantageously in the range from 1:10 to 10: 1, particularly preferably in the range from 1: 5 to 5: 1. In the context of the present invention, it may be expedient that the composition — depending on the application — contains further additives. Additives which are particularly useful in this context include further polymer resins, plasticizers, pigments, fillers, light stabilizers, preferably UV stabilizers, in particular benzotriazole derivatives, adhesion improvers, non-stick agents, theological auxiliaries, additives and substances which influence the pH, and chemical reactions between the polyvinyl acetal catalyze themselves or with the other polymer resins, if any, or between the polymer resins, if any, or cause them themselves. Additives that are particularly advantageous according to the invention are fiber-strengthening materials, in particular short glass fibers, long glass fibers, aramid fibers and / or carbon fibers.

The proportion of additives depends primarily on the intended application and thus the required property profile. Both very small amounts, for example only 0.001% by weight, based on the total weight of the composition, and very large amounts may be required. However, it has proven to be particularly favorable that the total proportion of additives, in each case based on the total weight of the composition, is at most 50.0% by weight, preferably at most 40.0, advantageously at most 35.0% by weight, preferably at most 30.0% by weight.

Methods for producing the composition according to the invention are immediately obvious to the person skilled in the art. If the composition comprises additives, the preparation can preferably be carried out by mixing the components, which can be done both stepwise and simultaneously. Furthermore, the addition of the oxalic acid and / or the antioxidant (s) can be used both in the preparation of the polyvinyl acetal, ie before or during the Acetalization of the starting polyvinyl alcohol, as well as during further processing, especially before extrusion, of the polyvinyl acetal is carried out by, in the latter case, preferably first dissolving or dispersing the oxalic acid and / or the antioxidants in a plasticizer and plasticizing the polyvinyl acetal with the plasticizer solution.

The antioxidant or antioxidants can preferably be added in the course of the preparation of the polyvinyl acetal by preferably adding the stabilizers to the aqueous polyvinyl alcohol solution to be acetahased, or if appropriate in drops in a water-dilutable solvent, such as methanol or methanol / acetone 1: 1, added dropwise , whereby the entire amount of stabilizer is well distributed in the resulting polyvinyl acetal.

On the other hand, the oxalic acid, as described above, can preferably be added in a dispersed manner in the plasticizer before the preferably thermoplastic processing of the polyvinyl acetal.

According to a further preferred embodiment of the present invention, the individual components and, if appropriate, further additives are mixed with one another in the respective amounts used by kneading, which is preferably carried out at a temperature below 230 ° C., in particular in the range from 100 to below 220 ° C.

According to a further preferred embodiment of the present invention, the components are mixed together in the respective amounts used by thermoplastic processing, preferably by means of an extruder. The thermoplastic processing is advantageously carried out at a temperature in the range from 100 to 300 ° C. Possible areas of use for the composition according to the invention are obvious to the person skilled in the art. It is particularly suitable for all applications which are drawn for polyvinyl acetals, in particular for polyvinyl formals and / or polyvinyl butyrals. Due to the characteristic property profile, however, it is particularly advantageous in applications in which the highest possible mechanical stability is desired.

Areas of application which are particularly preferred according to the invention include the use of the composition according to the invention as a raw material for the production of laminated glass films.

A particularly preferred area of application of the composition according to the invention in the context of the present invention is flat structures and moldings, in particular films or foils, preferably with a thickness in the range from 100 μm to 2.0 mm. Depending on the desired glass transition temperature Tg, these can contain certain amounts, preferably less than 100% by weight, in particular less than 60% by weight, based on the total amount of polyvinyl acetal, of conventional plasticizers or plasticizer mixtures.

The optionally plasticized polyvinyl acetals are preferably extruded by means of thermoplastic extrusion through slot dies to preferably 100 μm to 2.0 mm, in particular 0.2 to 2 mm thick flat films. The extrusion temperature of the extrusion molding compositions is in the usual range, preferably between 140 and 250 ° C., although higher temperatures can also be reached for a short time. Flat films can also be produced by thermoplastic molding of the stabilized polyvinyl acetal molding compositions according to the invention on a heatable three-roll mill or a calender. In addition to the stabilizers and plasticizers already mentioned above, the extrusion molding compositions may also contain other customary additives, such as, for example, small amounts of basic compounds, preferably for example 0.001 to 0.1% by weight, based on the polyvinyl acetal, alkali metal hydroxide or alkaline-reacting alkali metal salt for stabilization of polyvinyl acetal against acid hydrolysis. This alkali content is usually also referred to as the alkali titer of polyvinyl acetal. The plasticized polyvinyl acetal extrusion molding compositions can furthermore contain known non-stick agents in conventional amounts, for example alkali metal salts or alkaline earth metal salts of carboxylic acids, preferably potassium, sodium or magnesium salts of formic acid, acetic acid, higher carboxylic acids or of hydroxycarboxylic acids or combinations thereof. Furthermore, alkali metal or alkaline earth metal salts of dicarboxylic acids or magnesium acetylacetonate as well as various silanes or siloxanes, such as, for example, 3- (methyltriethylene glycoloxy) propylsilane-tris-methyltriethylene glycol ester. The amount of these non-stick agents used is preferably in the range from 0.001 to 0.2% by weight, based on the total weight of the composition according to the invention.

In addition, in the case of film extrusion of plasticized polyvinyl acetals, in particular polyvinyl butyrals, it is particularly important to be able to extrude at the highest possible melt temperatures, in order to lower the melt viscosity of the plasticized extrusion composition as much as possible or to keep it as low as possible and to achieve the highest possible extruder throughputs per unit of time without damaging the extrusion mass oxidatively and / or thermally and producing yellowing. By using stabilized polyvinyl acetals, these requirements can be largely met. Films obtainable according to the invention generally have at least 50% by weight, preferably at least 80% by weight and particularly preferably at least 95% by weight of a composition according to the invention, without any intention that this should impose a restriction.

After air conditioning at 23 ° C. and 30% relative atmospheric humidity, preferred films have a water content in the range from 0.6% by weight to 2.0% by weight, in particular from 0.7% by weight to 1.6% by weight. -%. This value generally results, inter alia, from the high content of hydrophilic and hydrophobic groups, these influences being known to the person skilled in the art.

The water content of the films is generally in the range from 0 to 2.0% by weight, in particular from 0.2 to 1.2% by weight, 0.4 to 0.6% by weight, based on the weight the slide. The water content of the film can be adjusted by conventional methods, for example drying or moistening.

According to a special aspect, the film can adhere to glass according to the compression shear test in the range from 1 to 30 N / mm ² , in particular from 5 to 25 N / mm ² .

Furthermore, the Pummel experiment shows that the films have excellent adhesion, as described in DE 101 00 681. The film can preferably have pummel values in the range from 2 to 10, particularly preferably 3 and 6, after lamination to 2.1 mm thick Planilux glass.

Furthermore, a film according to the invention can be provided with further layers in order to adjust the adhesion to glass to a desired area. For example, multilayer films can be produced by coextrusion which contain at least one polyvinyl acetal according to the invention Layer comprises further layers which, for example, have polyvinyl acetals with a lower proportion of structural units of the formula (1).

The films according to the invention show surprisingly good mechanical properties. For example, films with a tear strength of at least 30 N / mm, preferably at least 35 N / mm in accordance with DIN ISO 34-1 (draft May 2003) can be obtained from the compositions according to the invention.

In addition, the ball drop test according to ECE-R 43 shows that preferred films have a surprisingly high penetration resistance. In general, the films, which have a thickness of at least 0.76 mm, after lamination with 2.1 mm thick Planilux glass withstand a ball drop height of at least 5.75 m, preferably at least 6.0 m according to ECE-R 43, without this is to be a limitation.

According to a particular aspect of the present invention, the quotient from the falling height of the ball to the thickness of the film is preferably at least 7.5 m / mm, particularly preferably at least 7.9 m / mm.

The films described above are particularly suitable for the production of laminated safety glass, which is advantageously carried out in a known manner by the autoclave method, for the test glass laminates of 30 × 30 cm in an autoclave at 140 ° C., a pressure of 12 bar and a holding time of 2 hours getting produced. If the films are equipped with stabilizers, in particular oxalic acid and antioxidants, reduced discoloration or yellowing of the films can be determined in a known manner using the Yellowness Index in accordance with ASTM-D-1925. The invention is explained in more detail below by means of examples and comparative examples, without any intention that this should impose a restriction.

methods

Determination of the content of vinyl acetate units of polyvinyl acetals The polyvinyl acetal was dissolved in a benzyl alcohol / ethanol mixture. The acetate groups were saponified with an excess of alcoholic potassium hydroxide solution. The excess potassium hydroxide solution was titrated back with hydrochloric acid. The vinyl acetate unit content was calculated from the hydrochloric acid consumption.

Determination of the content of vinyl alcohol groups in polyvinyl acetals A mixture of pyridine and acetic anhydride was added to the polyvinyl acetal. After standing for 12 hours at 50 ° C. in a closed vessel, 1,2-dichloroethane and distilled water were added and the acetic acid formed was titrated with sodium hydroxide solution. The content of vinyl alcohol groups was calculated from the consumption of sodium hydroxide solution.

film production

Polyvinyl butyrals with different residual PVOH contents were mixed with different plasticizers before extrusion. The mixing took place in a laboratory mixer (manufacturer: Papenmeier, type TGHKV20 / KGU63). In the plasticizer of the mixtures, a UV stabilizer (eg Tinvin ^® 571, manufactured by Ciba Specialty Chemicals) were prior to preparation, and a certain amount of anti-blocking agent (for example Mg-Diisooctanoat or potassium acetate), dissolved or emulsified. Flat films with a thickness of 0.78 mm were extruded from the PVB / plasticizer mixtures. The extrusion was carried out using a twin-screw extruder with co-rotating screws (manufacturer: Leistritz), equipped with a melt pump and a slot die, at a melt temperature of 200 ° C. Tear strength

The tear propagation strength was determined on PVB films in accordance with DIN ISO 34-1 (draft May 2003) at 23 ° C and 50% relative humidity on angle test specimens without incision. The measurement was made lengthways and crosswise to the direction of extrusion. Before the test specimens were punched out, the films were pressed to a thickness of 0.76 mm at 100 ° C. and a pressure of 30 bar, the pressing time being 2 min. The test specimens were conditioned at 23 ° C. and 50% relative atmospheric humidity for 24 h before measurement. 6 test specimens were measured per film and the mean value was formed.

Manufacture of laminated safety glass

The PVB films were air-conditioned at a climate of 23 ° C and 30% relative humidity for 24 h. Laying took place between 2.1 mm thick Planilux glasses in fire / tin, fire / fire and tin / tin orientation of the glass surface to the film. The glass was washed with demineralized water before loading. The laminated glass panes were produced by pressing the composites in the pre-composite furnace with calender rolls at temperatures between 40 ° C and 100 ° C, followed by pressing the composites in an autoclave at a pressure of 12 bar and a temperature of 140 ° C for 30 min.

Measurement of film moisture

The film moisture was measured on the laminated glass with a reflective

Photometer from Pier Electromcs, Wallau, equipped with a measuring head type

10/03, measured. The calibration of the measuring device was carried out with calibration standards, on which the water content was determined absolutely by Karl Fischer titration. Pummel test

Test specimens with a size of 10 × 30 cm were cut from the laminated glasses to carry out the pummel test. The test was carried out in accordance with DE10100681. The adhesion of the film to the fire and the tin side of the glass was assessed.

Shear test measurement

10 test specimens with a size of 25.4 x 25.4 mm were cut from the laminated glasses for carrying out the shear test. The test specimens were tempered at 23 ° C./50% relative atmospheric humidity for 4 h before measurement. The test specimens are clamped in a sample holder according to Figure 1 at an angle of 45 °. The upper half of the test specimen is subjected to a steadily increasing, vertically downward force until a shear occurs between the glass and the film within the test specimen. The force required to shear was averaged over 10 test specimens for each example and standardized to the area of the test specimen.

Measurement of the fallow height / penetration resistance

Ball drop tests at 23 ° C with a steel ball weighing 2.26 kg were carried out on the laminated glass produced in accordance with ECE Regulation No. 43: "Uniform regulations for the approval of safety glass and glazing materials for motor vehicles and their trailers". Laminated glass panes measuring 30 x 30 cm with fire / tin orientation of the film to the glass surfaces were tested. The ball hit the tin side of the laminated glass. The safe fallow height (SBH) was determined in m, ie the maximum fall height at which the bullet did not break through when testing 6 test specimens. Molecular weight Mw

The determination of the molecular weights Mw (= weight average)

Polyvinyl butyrals were carried out by means of gel permeation chromatography (GPC)

Use of RI detectors. The detectors were calibrated using

PVB calibration standards, the absolute values of which were determined by means of static light scattering.

embodiments

Comparative Example 1

2250 g of PVB with a polyvinyl alcohol content of 20.4% by weight, a polyvinyl acetate content of 1.1% by weight and a molecular weight Mw of 104,000 g / mol, 750 g of dihexyl adipate, 4.5 g of Tinuvin 571 and 6 g of a 25 %, aqueous solution of potassium acetate used.

Example 2

2325 g of PVB with a polyvinyl alcohol content of 25.8% by weight, a polyvinyl acetate content of 1.3% by weight and a molecular weight Mw of 102000 g / mol, 675 g of tetraethylene glycol dimethyl ether (TEGDME), 4.5 g of Tinuvin 571 and 10 were obtained g of a 30% solution of Mg diisooctanoate in ethylene glycol monobutyl ether.

Example 3

2250 g of PVB with a polyvinyl alcohol content of 25.8% by weight, a polyvinyl acetate content of 1.3% by weight and a molecular weight Mw of 102000 g / mol, 375 g of tetraethylene glycol dimethyl ether (TEGDME), 375 g of dipropylene glycol dibenzoate, 4.5 g Tinuvin 571 and 14 g of a 30% solution of Mg diisooctanoate in ethylene glycol monobutyl ether.

The results of the test are summarized in Table 1. Table 1

Claims

claims: Composition comprising, based on the total weight of the composition, at least 10.0% by weight of at least one polyvinyl acetal, obtainable by a process in which a polymer (A) which, based on the total weight of the polymer (A), a) 25, 5 to 100.0% by weight of structural units of the formula (1)

wherein R ^{1 is} hydrogen or methyl, b) 0 to 74.5% by weight of structural units of the formula (2)

wherein R represents hydrogen or an alkyl radical having 1 to 6 carbon atoms, c) 0 to 70.0% by weight of structural units of the formula (3)

wherein R ³ , R ⁴ , R ⁵ and R ⁶ , each independently of one another, contain residues with a molecular weight in the range from 1 to 500 g / mol, are reacted with at least one compound (B) of the formula (4),

wherein R ⁷ and R ^{8 are} each independently hydrogen, COOH, COOM, an alkyl group having 1 to 10 carbon atoms or an optionally substituted aryl group having 6 to 12 carbon atoms and where M is a metal cation or an optionally alkylated ammonium cation, characterized in that the polyvinyl acetal obtained contains 25.5 to 50 wt .-% structural units of formula (1). 2. Composition according spoke 1, characterized in that between 20 and 70 parts by weight of compound (B), based on 100 parts by weight of polymer (A), is used. 3. Composition according to claim 1 or 2, characterized in that the composition comprises at least one plasticizer. 4. Composition according to claim 3, characterized in that the composition comprises at least 20 wt .-% plasticizer. 5. Composition according to claim 3 or 4, characterized in that the plasticizer comprises at least one dibenzoate of alkylene and / or polyalkylene glycols. 6. Composition according to one of the preceding claims 3 to 5, characterized in that the plasticizer comprises at least one ether of alkylene and / or polyalkylene glycols. 7. Composition according to one of the preceding claims, characterized in that the composition contains at least one stabilizer. 8. Composition according to one of the preceding claims, characterized in that the stabilizer comprises at least one antioxidant. 9. Composition according to one of the preceding claims, characterized in that the composition comprises oxalic acid. 10. Composition according to one of the preceding claims, characterized in that the composition contains non-stick agents. 11. A process for the preparation of a composition according to any one of claims 1 to 10, characterized in that a polymer (A) which, based on the total weight of the polymer (A), a) 25.5 to 100.0 wt .-% Structural units of the formula (1)

wherein R ^{1 is} hydrogen or methyl, b) 0 to 74.5% by weight of structural units of the formula (2)

wherein R ^{2 represents} hydrogen or an alkyl radical having 1 to 6 carbon atoms, c) 0 to 70.0% by weight of structural units of the formula (3)

wherein R ³ , R ⁴ , R ⁵ and R ⁶ , each independently of one another, contain residues with a molecular weight in the range from 1 to 500 g / mol, are reacted with at least one compound (B) of the formula (4),

wherein R ⁷ and R ^{8 are} each independently hydrogen, COOH, COOM, an alkyl group having 1 to 10 carbon atoms or an optionally substituted aryl group having 6 to 12 carbon atoms and where M is a metal cation or an optionally alkylated ammonium cation, characterized in that the polyvinyl acetal obtained contains 25.5 to 50 wt .-% structural units of formula (1). 12. A film containing at least 50% by weight of a composition according to any one of claims 1 to 10. 13. A film according to spoke 12, characterized in that the film has a tear resistance according to DIN ISO 34-1 of at least 30 N / mm. 14. Film according to spoke 12 or 13, characterized in that an at least 0.76 mm film after lamination with 2.1 mm thick Planilux Glass withstands a falling height of at least 5.75 m according to ECE-R 43. 15. Film according to one of claims 12 to 14, characterized in that the film has a thickness in the range from 100 μm to 2.0 mm. 16. Film according to one of claims 12 to 15, characterized in that the film has a multilayer structure. 17. The film according to claim 16, characterized in that at least one of the layers comprises at least one polyvinyl acetal which has at most 25% by weight of structural units of the formula (1). 18. Film according to one of claims 12 to 17, characterized in that the film after air conditioning at 23 ° C and 30% relative humidity shows a water content in the range from 0.6% by weight to 2.0% by weight. 19. Film according to one of claims 12 to 17, characterized in that the film has a water content in the range from 0.2 to 1.2% by weight. 20. Film according to one of claims 12 to 19, characterized in that the film has an adhesion to glass according to the compression shear test in the range from 1 to 30 N / mm ² . 21. A method for producing a film according to any one of claims 12 to 20, characterized in that extruding a composition according to one of claims 1 to 10. 22. Laminated glass comprising at least one film according to one of claims 12 to 20.