WO2004003028A1 - Polyvinyl acetals, the production and use thereof - Google Patents

Abstract

The invention relates to a method for producing polyvinyl acetals, which is characterised by the following: a blend of A.) 50.0 to 99.5 parts by weight of at least one polymer (A), which contains a.) 1.0 to 99.9 wt. % structural units of formula (1), b.) 0 to 99.0 wt. % structural units of formula (2), c.) 0 to 70.0 wt. % structural units of formula (3), each relating to the total weight of the polymer (A) and B.) 0.01 to 50.0 parts by weight of at least one hydroxy compound (B) of formula (4), C.) are reacted with at least one compound (C) of formula (5), whereby between 0.0005 and 0.5 mol of compound (C) is used per mol hydroxyl groups that are contained in total in the polymer (A) and the hydroxy compound (B). In said formulas, the groups R<1 >to R<10>, in addition to the index n are defined as cited in the description. In addition, the invention relates to polyvinyl acetals that are obtained by said method and to the use of the latter.

Description

 Polyvinyl acetals, their preparation and use

The present application relates to polyvinyl acetals, processes for their preparation and their use.

The modification of polyvinyl alcohol by acetalization is a long known and used reaction. Usually, this condensation reaction is carried out with fully hydrolyzed polyvinyl alcohols, wherein the reactions take place so far that water-insoluble products are obtained. In recent times, partially hydrolyzed polyvinyl alcohols were used as starting material, which gave polyvinyl butyrals with special properties (DE 198 16722 AI).

The partial reaction of the polyvinyl alcohols with aldehydes is known. In these processes, products are obtained which are still soluble in water. Such methods and products are u. a. described in DD-A 216028.

By a specific adjustment of the degree of conversion special products are still available that neither in pure water nor in pure solvent, eg. As ethanol, are soluble. Such products are soluble only in very specific mixing ratios of water and solvent.

In many applications of pure polyvinyl alcohols, the modified products (described above) and the highly acetalized polyvinyl acetals, the addition of plasticizers of any kind is required to achieve the desired properties in various applications. These are, for example, films of polyvinyl acetals, especially polyvinyl butyrals, for use as intermediate layers of automobile windows (front and side windows) and architectural (window) panes (structural glass panes). Also to be mentioned: the production of cast or extrusion foils from (modified) Polyvinyl alcohols, where appropriate amounts of plasticizers must be added in order either to enable the desired type of processing in the first place (extrusion) or to advantageously influence the properties of the products obtained (films, pouches, pouches, etc.) (flexibility, solubilities, sound insulation ). I

Known plasticizers for polyvinyl acetals are esters of aliphatic mono- and dicarboxylic acids with mono- or polyhydric alcohols or Oligoalkylenglykolethern and various phthalates, as described for example in US 5,137,954 A. However, the diesters of di-, tri- and tetraethylene glycols with aliphatic monocarboxylic acids and adipic acid dialkyl esters are preferably used. Triethylene glycol di-e-ethylhexanoate (see DE-A-24 53 780 and WO 97/24230) is frequently used in the art because it is readily compatible with the polyvinyl acetal, but especially with polyvinyl butyral, albeit only at low polyvinyl alcohol contents and is also available at low cost.

Furthermore, all these additives have in common that these are mixtures of one or more compounds (plasticizers, additives, etc. plus polymer), which are more or less compatible with each other. This has the consequence that such mixtures or blends segregate or separate by migration (exudation of the plasticizer). The consequence is that the (mechanical) properties of the products change (disadvantageously). For example, foams on films by the plasticizer accumulates on the surface and thus the film loses its elasticity.

It would therefore be desirable to have a process, as well as plastified acetal polymers produced thereafter, which contain substances acting as plasticizers but which advantageously do not have their separation from the remainder of the polymer. The prior art also discloses a process for the preparation of polyvinyl acetals in which the reaction of the polyvinyl alcohols with the aldehyde or ketone is not carried out in water but in ethanol, as otherwise customary (see Ullmann's Encyclopedia of Industrial Chemistry, Fifth Edition on CD-Rom Wiley-VCH, 1997, Keyword: Poly (Vinyl Acetals)). In practice, however, this method has not been able to prevail due to the increased amount of by-products. In addition, such a procedure leads to non-plasticized polyvinylactalene.

In view of the state of the art, it was therefore an object of the present invention to make available polyvinyl acetals which have comparable properties as the "plasticized" polyvinyl acetals and retain them for a longer period of time In particular, a change in the profile of properties of the polymers according to the invention by migration and / or or exuding components as much as possible.

A further object of the present invention was to provide a process for the preparation of the polymers according to the invention which can be carried out in a simple manner, industrially and inexpensively.

According to a third aspect of the present invention, particularly advantageous fields of application of the polymers according to the invention should also be pointed out.

These and other objects which are not explicitly mentioned, but which are readily derivable or deducible from the contexts discussed herein, are solved by polyvinyl acetals obtainable by a production process having all the features of patent claim 1. Advantageous modifications of the method according to the invention are provided in the dependent claims on claim 1 under protection. The polyvinyl acetals obtainable by the process according to the invention are characterized by Claimed product claims and the claims of the use category describe particularly advantageous -Einsatzgebiete the polyvinyl acetals of the invention.

By providing a process for the preparation of polyvinyl acetals, which is characterized in that a mixture of

A.) 50.0 to 99.99 parts by weight of at least one polymer (A) which contains a) 1.0 to 99.99% by weight of structural units of the formula (1)

wobei R¹ Wasserstoff oder Methyl bedeutet, b.) 0 bis 99,0 Gew.-% Struktureinheiten der Formel (2)

where R ^{1 is} hydrogen or methyl, b.) 0 to 99.0% by weight of structural units of the formula (2)

wobei R² Wasserstoff oder einen Alkylrest mit 1 bis 6 Kohlenstoffatomen darstellt, c.) 0 bis 70 Gew.-% Struktureinheiten der Formel (3)

where R ^{2 is} hydrogen or an alkyl radical having 1 to 6 carbon atoms, c.) 0 to 70% by weight of structural units of the formula (3)

wobei R³, R⁴, R⁵ und R⁶, jeweils unabhängig voneinander Reste mit einem Molekulargewicht im Bereich von 1 bis 500 g/mol sind, jeweils bezogen auf das Gesamtgewicht des Polymers (A) enthält, und B.) 0,01 bis 50,0 Gewichtsteilen mindestens einer Hydroxyverbindung (B) der Formel (4)

wherein R ³ , R ⁴ , R ⁵ and R ^{6 are} each independently radicals having a molecular weight in the range of 1 to 500 g / mol, based in each case on the total weight of the polymer (A), and B.) 0.01 to 50.0 parts by weight of at least one hydroxy compound (B) of the formula (4)

wobei R⁷ jeweils unabhängig voneinander Wasserstoff oder einen Alkylrest mit 1 bis 6 Kohlenstoffatomen bedeutet, R⁸ Wasserstoff oder einen

wherein R ⁷ is independently hydrogen or an alkyl group having 1 to 6 carbon atoms, R ^{8 is} hydrogen or a

Represents alkyl radical having 1 to 10 carbon atoms and n is a number greater than or equal to 2,

C.) with at least one compound (C) of the formula (5),

Λ _R '° ⁽⁵⁾ wherein R ⁹ and R ^{10 are} each independently hydrogen, COOH, an alkyl group of 1 to 10 carbon atoms or an optionally substituted aryl group of 6 to 12 carbon atoms, wherein per mole of hydroxyl groups containing the polymer (A ) and the hydroxy compound (B) in total 0.0005 to 0.5 mol of the compound (C), it is not readily predictable way to access polyvinyl acetals with improved properties, the comparable properties as the conventional " In particular, in the case of the polyvinyl acetals according to the invention, a change in the property profile due to separation, concentration, migration and / or exudation of components even after a prolonged period, such as one year, is not observed.

At the same time, a number of further advantages can be achieved by the method according to the invention: A "softening" of the polyvinyl acetals obtainable by the process according to the invention, for example by adding conventional plasticizers, is no longer necessary.

The process according to the invention makes it possible to produce the polyvinyl acetals according to the invention in a simple manner, industrially and cost-effectively.

=> The polyvinyl acetals according to the invention can be used in many ways. Their application is not limited to the known fields of use of conventional polyvinyl acetals, but due to their significantly improved long-term stability of their properties, they are also suitable for new applications, which are closed for the conventional polyvinyl acetals.

The polymers according to the invention are obtainable by a process in which a mixture of

A.) 50.0 to 99.99 parts by weight of at least one polymer (A) and

B.) 0.01 to 50.0 parts by weight of at least one hydroxy compound (B)

C.) with at least one compound (C) of the formula (5).

The sum of the parts by weight of A.) and B.) is preferably 100 parts by weight.

b.) 0 bis 99,0 Gew.-% Struktureinheiten der Formel (2)The polymer (A) contains, based in each case on its total weight a) 1.0 to 99.9% by weight of structural units of the formula (1)

b.) 0 to 99.0% by weight of structural units of the formula (2)

c.) 0 bis 70,0 Gew.-%, vorzugsweise 0,01 bis 70,0 Gew.-%, Struktureinheiten der Formel (3)

c.) 0 to 70.0% by weight, preferably 0.01 to 70.0% by weight, of structural units of the formula (3)

Of course, 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 comprise the structural units of the formula (1) or (2).

The radical R ¹ is in each case independently of one another hydrogen or methyl, preferably hydrogen.

The radical R ² denotes hydrogen or an alkyl radical having 1 to 6 carbon atoms, preferably an alkyl radical having 1 to 6 carbon atoms, suitably 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 radicals having a molecular weight in the range of 1 to 500 g / mol, suitably hydrogen, an optionally branched, aliphatic or cycloaliphatic radical having 1 to 16 carbon atoms, optionally may contain one or more carboxylic acid, carboxylic anhydride, carboxylic acid ester, carboxylic acid amide and / or sulfonic acid groups.

Particularly preferred control units of the formula (3) are derived from straight-chain or branched olefins having 2 to 18 carbon atoms, (meth) acrylic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid, (meth) acrylamides and / or ethylene sulfonic acid. In this case, olefins, in particular those having a terminal C-C double bond, which preferably have 2 to 6 carbon atoms, in particular ethylene. proved to be particularly favorable. Furthermore, structural units (3) 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 of 0.1 to 40 mol%, preferably in the range of 0.5 to 25.0 mol%, especially in the range of 1.0 to 15.0 mol -%, in each case based on the total number of structural units of the formula (1) and (2). In this case, according to a first preferred embodiment of the present invention, a polymer (A) is used, which contains based on the total number of structural units of the formula (1) and (2) 1.0 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 from 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> 50.0% by weight, expediently> 60.0% by weight, advantageously> 70.0% by weight , In particular> 80.0 wt .-% of Strakmreinheiten of formula (1) and / or (2). Particularly advantageous results can be achieved with polymers (A) which, based in each case on their total weight, are> 85.0% by weight, expediently> 90.0% by weight, advantageously> 95.0% by weight, in particular> 99.0% by weight of structural units of the formula (1) and / or (2).

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

The viscosity of the polymer (A) is according to the invention of minor importance, in principle, both low molecular weight and high molecular weight polymers (A) can be used. Nevertheless, it has been found within the scope of the present invention to be particularly favorable that the polymer (A) has a viscosity in the range from 1 to 70 mPas, preferably in the range from 2 to 40 mPas, in particular in the range from 3 to 30 mPas (measured as 4% by weight aqueous solution according to Hoppler at 20 ° C., DIN 53015).

The preparation of the polymers (A) to be used according to the invention can be carried out in a manner known per se in a two-stage process. In a first step, the corresponding vinyl ester is radically polymerized in a suitable solvent, usually water or an alcohol, such as methanol, ethanol, propanol and / or butanol, 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, wherein the degree of saponification can be adjusted in a known manner, for example by varying the catalyst concentration, the reaction temperature and / or the reaction time. For further details reference is made to the standard literature, in particular to Ulhnann's Encyclopedia of Industrial Chemistry, Fifth Edition on CD-Rom Wiley-VCH, 1997, Keyword: Poly (Vinyl Acetals) and the references cited therein.

The hydroxy compound (B) according to the invention satisfies the formula (4)

The radical R ⁷ denotes hydrogen or an alkyl radical having 1 to 6 carbon atoms, preferably a methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, tert-butyl, n-butyl Pentyl or an n-hexyl group, in particular a methyl group. In a very particularly preferred embodiment of the present invention, the radical R ^{7 is} hydrogen.

In this case, the radicals R ^{7 can} each be selected independently of one another, ie each repeating unit -CHR ⁷ -CH ₂ -O- can have a different radical R ⁷ . Thus, the above definition of the hydroxy compound (B) includes both polyethylene glycol (monoether) and polypropylene glycol (monoether) and polyethylene glycol-co-propylene glycol (monoether). The latter can have both a statistical and a block-like structure.

The radical R ⁸ denotes hydrogen or an alkyl radical having 1 to 10 carbon atoms, preferably a methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, tert-butyl, n-butyl Pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl or n-decyl, in particular a methyl group. According to one In a very particularly preferred embodiment of the present invention, the radical R ^{8 is} hydrogen.

n is a number greater than or equal to 2, preferably a number in the range from 2 to 1000, advantageously in the range from 3 to 300, advantageously in the range from 3 to 25, particularly preferably in the range from 3 to 10, in particular in the range from 4 to 6. Furthermore, particularly favorable results can be achieved if n is a number in the range of 10 to 20, in particular in the range of 12 to 15.

The compound (C) according to the invention has the formula (5)

The radicals R ⁹ and R ¹⁰ are each independently hydrogen, COOH, an alkyl group having 1 to 10 carbon atoms or an aryl group having 6 to 12 carbon atoms. These alkyl and aryl radicals may be substituted by one or more carboxyl, hydroxyl, sulfonic acid groups and / or halogen atoms, such as fluorine, chlorine, bromine, iodine. Preferred compounds (C) include formaldehyde, acetaldehyde, propionaldehyde, n-butyraldehyde, isobutyraldehyde, 2-ethoxybutyraldehyde, paraldehyde, 1,3,5-trioxane, capronaldehyde, 2-ethylhexanal, pelargonaldehyde, 3,5,5- Trimethylhexanal, 2-formyl-benzoesulfonic acid, acetone, ethyl methyl ketone, butyl ethyl ketone and / or ethyl hexyl ketone. According to another preferred embodiment, glyoxylic acid HCO-COOH is used as compound (C).

In the context of the present invention, the use of aldehydes, ie compounds of formula (5) where R ⁹ = hydrogen and R ¹⁰ = hydrogen, a methyl, ethyl, n-propyl or iso-propyl group, preferably of formaldehyde and / or n-butyraldehyde, in particular of n-butyraldehyde, very particularly proven.

The proportions of the starting compounds (A), (B) and (C) are selected according to the invention such that from 0.0005 to 0.5 mol per mole of hydroxyl groups which contain the polymer (A) and the hydroxy compound (B) in total the compound (C) is used.

Moreover, the compounds (B) and (C) are preferably used in a compound (C) / compound (B) ratio greater than or equal to one.

The reaction of the starting compounds (A), (B) and (C) is preferably carried out in at least one inert solvent, the term "inert solvent" being those solvents which do not react with the compounds present in the reaction system under the respective reaction conditions particularly useful solvent in this context is water.

Furthermore, the reaction is conveniently carried out in the presence of acidic catalysts. Suitable acids include both organic acids, such as, for example, acetic acid and 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 the art. The reaction is preferably carried out by initially charging a mixture of components (A) and (B) in aqueous solution, adding compound (C) to this solution, and then dropping the acidic catalyst. According to a further preferred embodiment of the present invention, it has also proved to be favorable to initially charge a mixture of components (A) and (B) in aqueous solution, to stir the acidic catalyst into this solution and then to react the reaction by addition of the compound (C ) to start. The reaction temperature can be varied over a wide range, but often the temperature is in the range of -20.0 ° C to 100.0 ° C, preferably in the range of 0.0 ° C to 80.0 ° C. The same applies to the pressure at which the implementation is completed. Thus, the reaction can take place both at low pressure and at overpressure. Preferably, however, it is carried out at atmospheric pressure. Although the reaction can also take place under air, it has proven favorable in the context of the present invention to carry out the reaction under a protective gas atmosphere, preferably nitrogen and / or argon, wherein preferably a low oxygen content is present.

The solubility behavior of the polymers according to the invention can be adjusted via the degree of acetalization. This increases in the course of the reaction, whereby the solubility of the resulting product in the aqueous medium decreases. By shifting the hydrophilic-lipophilic balance (HLB) increasingly towards hydrophobic, the product separates from the aqueous phase, visible first by clouding of the solution and finally by complete precipitation from the same. The "finalized" final product is no longer soluble in water and is separated as a solid and, after appropriate work-up, recovered as a pure product.

If the amount of compound (C) is now reduced, the reaction continues until the total consumption of the same. Depending on the amount used, the product is completely water-soluble or shows a temperature-dependent cloud point with increasing acetalization, ie the solubility of the polymer in water - at a given temperature - depends on the level of the reaction. In this way, it is also possible to produce products which, although in the synthesis of the aqueous phase ausölen by the addition of organic solvents, eg. As alcohols, such as ethanol, but can be completely dissolved again. These products are then only in this special, the HLB Value of the polymer adapted, mixture soluble. Films produced therefrom are then soluble neither in pure water nor in the organic solvent.

Alternative methods of preparation of the polymers of the invention will be apparent to those skilled in the art. For example, instead of the compound (C) it is possible to use compounds which release compounds (C) under the chosen reaction conditions. These include u. a. cyclic trimers of aldehydes and acetals of aldehydes or ketones. Furthermore, it is of course also possible to first partially acetalize the polymer (A) by reaction with an appropriate amount of compound (C), then to admix the hydroxy compound (B) and to react the resulting mixture with a further amount of compound (C).

The structure of the polyvinyl acetals according to the invention is not yet completely clarified at the present time. Nevertheless, the present results indicate that the hydroxy compound (B) is covalently bound to the polymer since, unlike conventional plasticizers, it is no longer polymerizable, for example by extraction (eg, by Soxhlet extraction ), isolate. It is understood, however, that the teachings of the present invention are not limited to this interpretation.

The property profile of the polyvinyl acetals according to the invention differs markedly both from conventional polyvinyl acetals which contain no plasticizer and from those polyvinyl acetals which have been plasticized at the same degree of conversion (degree of acetalization) by the addition of plasticizer. For example, compared to conventional polyvinyl acetals containing no plasticizer, the polyvinyl acetals of the present invention, at the same degree of acetalization, have a lower glass transition temperature, an increased shape-changing ability, a lower entropy elasticity elastic properties, lower hardness and usually increased adhesion.

Compared to the polyvinyl acetals, which were plasticized with the same degree of conversion (degree of acetalization) by the addition of plasticizer, they are characterized in particular by improved long-term stability of their properties, especially in the polyvinyl acetals according to the invention a change in the property profile by separation, concentration, migration and / or Exudation of components by atmospheric influences even after a long time, such as a year, not observed. In this context, atmospheric influences are understood as meaning all the factors that may occur when using the polyvinyl acetals according to the invention, in particular outdoors, such as sunlight, oxygen, ozone, other gaseous components of air, temperature, humidity, precipitation, dust deposits, etc ..

These improved long-term properties, in particular when comparing the glass transition temperature (preferably measured by DSC, Mettler Toledo Star System, heating rate lOK / min, 2. heating), the entropy elastic modulus (preferably measured according to DIN 7724 (February 1972)), the tear strength (preferably measured according to DIN 53455), the elongation at break (preferably measured according to DIN 53455), the water absorption and / or the surface tension of the polyvinyl acetals according to the invention with conventionally externally plasticized polyvinyl acetals are observed.

The products of the invention can be processed in a conventional manner and show novel and special properties in many applications. For example, the solubility in pure water is adjustable as desired over the HLB value. The objects and moldings produced therefrom may, in their solubility, interact with the special conditions of their interaction be adapted to passing media. For example, the solubility can be optimized to specific pH ranges without the objects losing their properties, such as flexibility and resilience. This is particularly advantageous when packaging household chemicals or agrochemicals. Films from the products according to the invention can be optimized for good solubility, for example at pH 2, which was previously not possible with commercial products. Also, the solubility in the alkaline is often not given. Again, the products of the invention represent a solution.

Possible fields of application for the highly transparent plastic according to the invention are obvious to the person skilled in the art. It is particularly suitable for all applications that are predetermined for polyvinyl acetals, especially for polyvinyl formal and / or Polyvmylbutyrale. Preferred applications include their use as laminated glass sheets and for adhesives and peelable coatings. Also, they are particularly advantageous as fibers.

In many cases, new, expanded areas of application will be accessible; for example in the field of additives for construction chemicals (tile adhesive, mortar, cementitious materials and the like), in the field of emulsion and suspension polymerization.

A particularly preferred field of application of the polyvinyl acetals according to the invention in the context of the present invention are fabrics, in particular films, preferably having a thickness in the range from 0.5 μm to 1 mm. These can - depending on the desired glass transition temperature Tg - small amounts, preferably less than 10% by weight based on the total amount of polyvinyl acetal, conventional plasticizers such as phthalates, trimellitates, acyclic aliphatic dicarboxylic acid esters, phosphates, fatty acid esters, especially triethylene glycol bis (2 -ethylbutyrat) and / or hydroxycarboxylic acid esters. Nevertheless, it has been found in the context of the present invention to be particularly favorable that the polyvinyl acetals contain no further additives.

According to a very particularly preferred embodiment of the present invention, the polyvinyl acetal films are used as a film composite which has at least one layer of the polyvinyl acetal according to the invention. Preferably, they are laminated to multilayer sandwich films for security interlayer, which can be used in the field of sound insulation. The sound insulation in such glass composites is z. Zt. Achieved by z. B. the intermediate film used are mixed with very large amounts of suitable plasticizer to the necessary low glass transition temperature of z. B. 10-20 ° C to reach. The migration has already been pointed out above, especially in the case of solar radiation and the resulting harmful effects. Another method consists of laminating such "sound insulation foils" on both sides with films of conventional polyvinyl acetal films which contain substantially less plasticizer, in order to optimize the sound barrier effect deteriorate.

In contrast, a film of the polyvinyl acetal according to the invention has a substantially lower glass transition temperature with the same external plasticization as conventional polyvinyl acetal types. If you hide these two types with z. B. same plasticizer content, thus resulting in a migration-free composite film with adjusted sound insulation and temporally constant overall properties. Even better results can be achieved with a composite film which is obtainable by laminating various types of polyvinyl acetal according to the invention, which differ preferably in the glass transition temperature and are preferably free of plasticizer. The following examples and the comparative example serve to illustrate the invention, without this being intended to limit it. The polyvinyl alcohols used are described according to the nomenclature used by Kuraray Specialties Europe GmbH (KSE). The number mentioned in the type designation at the first position indicates the viscosity of the 4% aqueous solution at 20 ° C as a relative measure of the degree of polymerization of the polyvinyl alcohols; the second number indicates the degree of hydrolysis (degree of saponification) of the type of polyvinyl acetate on which the type is based (partially hydrolyzed and fully hydrolyzed polyvinyl alcohol types). The usual fluctuations in the characteristic data given by the company Kuraray Specialties Europe GmbH apply, ie, the viscosity may have a fluctuation of ± 0.5 mPa s, the degree of hydrolysis a fluctuation of ± 1 mol%.

Example 1:

504 g of polyvinyl alcohol Mowiof 10-98 are dissolved in 6696 ml of water. After introduction of 50.4 g of polyethylene glycol PEG 200, 320 g of n-butyraldehyde are added. By addition of 20 wt .-% hydrochloric acid solution, the reaction is started at 5 ° C. The total dosing time for a total of 1008 ml of hydrochloric acid is 180 minutes. After completion of the hydrochloric acid dosing, the reaction solution is heated to 30 ° C over a period of 2 hours and held at this temperature for a further 2 hours. The precipitated solid is filtered off and washed sufficiently with water and made alkaline with 10 wt .-% sodium hydroxide solution. Excess liquor is removed by brief washing with water. Subsequently, the product is dried. The product obtained has a residual acetate content of 1.59 mol% based on the total number of all OH groups in the originally used Mowiol and a residual Polyvmylalkoholgehalt of 20.14 mol- based on the total number of all OH groups in the originally used Mowiol. The viscosity according to Hoppler according to DIN 53015 amounts to 10% by weight solution in ethanol 440 mPas and with a 5% strength by weight solution in butanol 113 mPa s. The glass point (Tg) determined by DSC measurement is 70 ° C.

Example 2:

504 g of polyvinyl alcohol Mowiof 28-99 are dissolved in 6696 ml of water. After adding 50.4 g of polyethylene glycol PEG 200, 325 g of n-butyraldehyde are added. By addition of 20 wt .-% hydrochloric acid solution, the reaction is started at 5 ° C. The total dosing time for a total of 1008 ml of hydrochloric acid is 180 minutes. After completion of the hydrochloric acid dosing, the reaction solution is heated to 30 ° C over a period of 2 hours and held at this temperature for a further 2 hours. The precipitated solid is filtered off and washed sufficiently with water and made alkaline with 10 wt .-% sodium hydroxide solution. Excess liquor is removed by brief washing with water. Subsequently, the product is dried. The product obtained has a residual acetate content of 1.09 mol% based on the total number of all OH groups in the originally used Mowiol and a residual polyvinyl alcohol content of 20.34 mol- based on the total number of all OH groups in the originally used Mowiol. The viscosity according to Hoppler according to DIN 53015 is 173 mPa s for a 5% by weight solution in ethanol and 570 mPa s for a 5% strength by weight solution in butanol. The glass point (Tg) determined by DSC measurement is 72 ° C.

Example 3:

504 g of polyvinyl alcohol Mowiof 18-88 are dissolved in 6696 ml of water. After adding 61.7 g of triethylene glycol, 314 g of n-butyraldehyde are added. By adding 20% strength by weight hydrochloric acid solution, the reaction is started at 1 ° C. After metering in 16% of the total amount of HCl over a period of 40 minutes, the metered addition is stopped for 60 minutes. The total dosing time for a total of 1008 ml of hydrochloric acid is 180 minutes. After completion of the hydrochloric acid dosing, the reaction solution is heated over a period of 2 hours at 30 ° C and a further hour at maintained this temperature. The precipitated solid is filtered off and washed sufficiently with water and made alkaline with 10 wt .-% sodium hydroxide solution. Excess liquor is removed by brief washing with water. Subsequently, the product is dried. The Höppler viscosity in accordance with DIN 53015 is 854 mPas for a 10% by weight solution in ethanol and 2805 mPas for a 10% by weight solution in butanol. The glass point (Tg) determined by DSC measurement is 66 ° C.

Example 4:

504 g of polyvinyl alcohol Mowiof 4-98 are dissolved in 6696 ml of water. After adding 50.4 g of Genapol PF 10, 321 g of n-butyraldehyde are added. By addition of 20 wt .-% hydrochloric acid solution, the reaction is started at 5 ° C. The total dosing time for a total of 1008 ml of hydrochloric acid is 120 minutes. Then it is stirred for 30 minutes. Subsequently, the reaction solution is heated to 30 ° C over a period of 2 hours and held at this temperature for a further hour. The precipitated solid is filtered off and washed sufficiently with water and made alkaline with 10 wt .-% sodium hydroxide solution. Excess liquor is removed by brief washing with water. Subsequently, the product is dried. The Höppler viscosity according to DIN 53015 is 31.55 mPa s in the case of a 10% by weight solution in ethanol and 115 mPa s in the case of a 10% strength by weight solution in butanol. The glass point (Tg) determined by DSC measurement is 62 ° C.

Example 5:

504 g of polyvinyl alcohol Mowiof 8-88 are dissolved in 6696 ml of water. After adding 50.4 g of Genapol PF 20, 258 g of n-butyraldehyde are added. By addition of 20 wt .-% hydrochloric acid solution, the reaction is started at 5 ° C. The total dosing time for a total of 1008 ml of hydrochloric acid is 120 minutes. Then it is stirred for 30 minutes. Subsequently, the reaction solution is heated to 30 ° C over a period of 2 hours and held at this temperature for a further hour. The precipitated solid is filtered off and washed sufficiently with water and made alkaline with 10 wt .-% sodium hydroxide solution. Excess liquor is removed by brief washing with water. Subsequently, the product is dried. The Höppler viscosity according to DIN 53015 is 325 mPa s for a 10% by weight solution in ethanol and 945 mPa s for a 10% strength by weight solution in butanol. The glass point (Tg) determined by DSC measurement is 69 ° C.

Example 6:

504 g of polyvinyl alcohol Mowiof 28-99 are dissolved in 6696 ml of water. After adding 50.4 g of Genapol PF 20, 325 g of n-butyraldehyde are added. By addition of 20 wt .-% hydrochloric acid solution, the reaction is started at 5 ° C. The total dosing time for a total of 1008 ml of hydrochloric acid is 120 minutes. Then it is stirred for 30 minutes. Subsequently, the reaction solution is heated to 30 ° C over a period of 2 hours and held at this temperature for a further hour. The precipitated solid is filtered off and washed sufficiently with water and made alkaline with 10 wt .-% sodium hydroxide solution. Excess liquor is removed by brief washing with water. Subsequently, the product is dried. The Höppler viscosity according to DIN 53015 is 136 mPa s for a 5% strength by weight solution in ethanol and 453 mPa s for a 5% strength by weight solution in butanol. The glass point (Tg) determined by DSC measurement is 71 ° C.

Example 7:

Polyvinyl alcohol Mowiof 26-88 (1080 g) is dissolved in E-water (6120 g) according to the known manner. After cooling the solution, 43.2 g of polyethylene glycol PEG 200 (corresponding to 4 mol% based on the polyvinyl alcohol used) and n-butyraldehyde (27.6 g, 4 mol%, based on the polyvinyl alcohol used) are stirred at 40 ° C. with stirring ) was added. At room temperature, a quantity of 200 ml of 20% strength by weight hydrochloric acid is metered in over a period of 120 minutes and then stirred for 120 minutes. With 10 wt .-% sodium hydroxide solution is then to pH 7 to 8 set. The pH is monitored over a period of 2-3 hours and readjusted if necessary. The product obtained has a viscosity of 19.63 mPa s (4 wt .-% water, Hoppler, DIN 53015) and 229 mPa s (8 wt .-% in water, Höppler, DIN 53015). The cloud point at 4 wt .-% aqueous solution is 56 ° C, at 8 wt .-% aqueous solution 50 ° C. The precipitation points at 4 wt .-% aqueous solution are 67 ° C, at 8 wt .-% aqueous solution 66 ° C. The glass point (Tg) determined by DSC measurement is 70 ° C.

Comparative Example 1

Example 7 was repeated, but without the addition of polyethylene glycol PEG 200. The analytical data are as follows: viscosity 21.7 mPa s (4% by weight in water, Höppler, DIN 53015) or 270 mPa s (8% by weight in water, Höppler, DIN 53015). The cloud point at 4 wt .-% aqueous solution is 61 ° C, at 8 wt .-% aqueous solution 72 ° C. The precipitation points at 4 wt .-% aqueous solution are 69 ° C, at 8 wt .-% aqueous solution 75 ° C. The glass point (Tg) determined by DSC measurement is 75 ° C.

Example 8:

900 g of a carboxyl-containing polyvinyl alcohols having an initial viscosity of 14 m Pas (4 wt .-% aqueous solution, Höppler, DIN 53015) and a degree of hydrolysis of 95 mol% were dissolved in 6300 ml of water, creating a 12.5 wt .-% polyvinyl alcohol solution was obtained. After cooling to about 40 ° C., 90 g of polyethylene glycol PEG 200 (10% by weight, based on the polyvinyl alcohol used) and 66 g of n-butyraldehyde were introduced into this solution and stirred for 5 minutes. At ambient temperature, 422 ml of a 20% strength by weight hydrochloric acid were metered in to achieve a pH of 1. The reaction was started automatically by the acid addition and carried out at room temperature. After dosing, the mixture was stirred for 120 minutes at this temperature. With sodium hydroxide (10 wt .-%) was then set a neutral to slightly alkaline pH (consumption: approx. 940 ml). The product solution thus obtained had a solids content of 13.4 wt .-%. The viscosity according to Hoppler according to DIN 53015 was 8.5 mPas for a 4% strength by weight aqueous solution and 55 mPas for an 8% strength by weight aqueous solution. The product solution had neither a cloud point at 43 ° C. (4% by weight aqueous solution) and a precipitation point at 55 ° C. (4% by weight aqueous solution).

From the aqueous solution, a film was produced by casting technology and determined its properties. The values obtained are shown in Table 1.

Table 1:

Example 9:

The procedure was as in Example 9, but using 15 wt .-% polyethylene glycol PEG 200, based on the polyvinyl alcohol used. The properties of a film obtained therefrom are also shown in Table 1.

Comparative Example 2:

The procedure was as in Example 9, but without polyethylene glycol PEG 200. The properties of a film obtained therefrom are also shown in Table 1.

Example 10:

1080 g of polyvinyl alcohol Mowiof 8-88 are dissolved in 6,120 ml of water. After entry of 108 g of polyethylene glycol PEG 200 is a mixture of 69.4 g n-. Added butyraldehyde and 42.3 g of paraldehyde. By adding 20% strength by weight hydrochloric acid solution until it reaches a pH of about 1 (195 ml), the reaction is started at 22 ° C. After completion of the hydrochloric acid metering, the reaction solution is stirred for a period of 2 hours. With 10% by weight sodium hydroxide solution is made alkaline (500ml). The Höppler viscosity according to DIN 53015 is 6.7 mPa s for a 4% strength by weight aqueous solution and 39.8 mPa s for an 8% strength by weight aqueous solution. The glass point (Tg) determined by DSC measurement is 60 ° C.

Example 11: 1080 g of polyvinyl alcohol Mowiof 10-98 are dissolved in 6,120 ml of water. After the addition of 108 g of polyethylene glycol PEG 200, a mixture of 86.0 g of n-butyraldehyde and 52.5 g of acetaldehyde is added. By metering in 20% strength by weight hydrochloric acid solution until a pH of about 1 is reached (200 ml), the reaction is started at 20 ° C. After completion of the hydrochloric acid metering, the reaction solution is stirred for a period of 2 hours. With 10 wt .-% sodium hydroxide solution is made alkaline (455 ml). The viscosity according to Hoppler according to DIN 53015 is 8.4 mPa e for a 4% strength by weight aqueous solution and 59 mPa s for an 8% strength by weight aqueous solution. The glass point (Tg) determined by DSC measurement is 71 ° C.

Comparative Example 3

Example 11 was carried out but without the addition of polyethylene glycol PEG 200. The analytical data are as follows: Viscosity 10.8 mPa s (4 wt%, aqueous solution, Hoppler, DIN 53015) and 90.5 mPa s (8 wt%, aqueous solution, Hoppler). The glass point (Tg) determined by DSC measurement is 85 ° C.

Example 12:

100 kg of polyvinyl alcohol Mowiof 18-88 are dissolved in 567 kg of water. After adding 5000 g of polyethylene glycol 200, 3.24 kg of n-butyraldehyde are added. By addition of 20 wt .-% hydrochloric acid solution, the reaction is started at 20 ° C (24.1 1). After completion of the hydrochloric acid metering, the reaction solution is stirred for a period of 2 hours. With 10 wt .-% sodium hydroxide solution is made alkaline (60.2 1). The Höppler viscosity according to DIN 53015 is 13.17 mPa s for a 4% strength by weight aqueous solution and 120.50 mPa s for an 8% strength by weight aqueous solution. The cloud point at 4 wt .-% aqueous solution is -42 ° C, at 8 wt .-% aqueous solution -40 ° C. The precipitation points at 4 wt .-% aqueous solution are -58 ° C, at 8 wt .-% aqueous solution -60 ° C. Example 13:

100 kg of polyvinyl alcohol Mowiof 26-88 are dissolved in 566.67 kg of water. After introduction of 13000 g of polyethylene glycol 200, 5.22 kg of n-butyraldehyde are added. By addition of 20 wt .-% hydrochloric acid solution, the reaction is started at 20 ° C (15.0 1). After completion of the hydrochloric acid metering, the reaction solution is stirred for a period of 2 hours. With 10 wt .-% sodium hydroxide solution is made alkaline (26.4 1). The Höppler viscosity according to DIN 53015 is 17.46 mPa s for a 4% strength by weight aqueous solution and 236.4 mPa s for an 8% strength by weight aqueous solution. The cloud point at 4 wt .-% aqueous solution is -37 ° C, at 8 wt .-% aqueous solution -36 ° C. The precipitation points at 4 wt .-% aqueous solution are -41 ° C, at 8 wt .-% aqueous solution -41 ° C.

Example 14:

100 kg of polyvinyl alcohol Mowiof 28-99 are dissolved in 900 kg of water. After adding 3000 g of polyglycol B 11/50, 6.54 kg of n-butyraldehyde are added. By addition of 20 wt .-% hydrochloric acid solution, the reaction is started at 20 ° C (23.6 1). After completion of the hydrochloric acid metering, the reaction solution is stirred for a period of 2 hours. With 10 wt .-% sodium hydroxide solution is made alkaline; pH 8 (52.8 1). The Höppler viscosity in accordance with DIN 53015 is 23.94 mPa s for a 4% strength by weight aqueous solution and 327.40 mPa s for an 8% strength by weight aqueous solution. The cloud point at 4% by weight is -46 ° C, at 8% by weight -44 ° C. The precipitation points at 4 wt .-% solution are -56 ° C at 8 wt .-% solution -60 ° C.

Example 15:

100 kg of polyvinyl alcohol Mowiof 4-88 are dissolved in 567 kg of water. The solution is heated to 95 ° C for at least 30 minutes. At about 50 - 40 ° C. internal temperature, 5000 g of polyethylene glycol 200 are introduced. After stirring for 30 minutes 3.25 kg of n-butyraldehyde are added. By addition of 20 wt .-% hydrochloric acid solution, the reaction is started at 20 ° C (5.6 1). After completion of the hydrochloric acid metering, the reaction solution is stirred for a period of 2 hours. With 10% by weight sodium hydroxide solution is made alkaline; pH 8 (25.1 l). The Höppler viscosity in accordance with DIN 53015 is 23.94 mPa s for a 4% strength by weight aqueous solution and 327.40 mPa s for an 8% strength by weight aqueous solution. The cloud point at 4 wt .-% aqueous solution is -70 ° C at 8 wt .-% aqueous solution -74 ° C. Precipitation points are not observed.

In the table below, a multiplicity of modifications has been carried out by way of example for a partially hydrolyzed and a fully hydrolyzed polyvinyl alcohol, here Mowiol 18-88 or 28-99, and the analytical data of the products obtained have been determined (see Tables 2 and 3).

Table 2: Polymer (A): Mowiol 18-88, degree of acetalization: 8 mol% based on the total number of all OH groups in Mowiol, compound (B): PEG 200, compound (C): n-butyraldehyde

: bezogen auf das Gesamtgewicht des Polymers n.b. nicht bestimmt

: Not determined based on the total weight of polymer nb

Table 3: Polymer (A): Mowiol 28-99, degree of acetalization: 8 mol% based on the total number of all OH groups in Mowiol, compound (B): PEG 200, compound (C): n-butyraldehyde

bezogen auf das Gesamtgewicht des Polymers

based on the total weight of the polymer

Table 4: Polymer (A): Mowiol 18-88, degree of acetalization: 8 mol% based on the total number of all OH groups in Mowiol, compound (C): n-butyraldehyde

n.b. nicht bestimmt

nb not determined

Claims

Claims: 1. A process for the preparation of polyvinyl acetals, characterized in that a mixture of A.) 50.0 to 99.99 parts by weight of at least one polymer (A) which contains a) 1.0 to 99.9% by weight of structural units of the formula (1)

where R ^{1 is} hydrogen or methyl, b.) 0 to 99.0% by weight of structural units of the formula (2)

wherein R ^{2 is} hydrogen or an alkyl radical having 1 to 6 C.) 0 to 70.0% by weight of structural units of the formula (3)

wherein R ³ , R ⁴ , R ⁵ and R ^{6 are} each independently radicals having a molecular weight in the range of 1 to 500 g / mol, based in each case on the total weight of the polymer (A), and B.) 0.01 to 50.0 parts by weight of at least one hydroxy compound (B) of the formula (4)

wherein R ^{7 are} each independently hydrogen or a Alkyl radical having 1 to 6 carbon atoms, R ^{8 represents} hydrogen or an alkyl radical having 1 to 10 carbon atoms and n is a Number greater than or equal to 2, C.) with at least one compound (C) of the formula (5), Λ _R. ° ⁽⁵⁾ wherein R ⁹ and R ¹⁰ are each independently hydrogen, COOH, an alkyl group having 1 to 10 carbon atoms or an optionally substituted aryl group having 6 to 12 carbon atoms, being used per mol hydroxyl groups which the polymer (A ) and the hydroxy compound (B) in total, 0.0005 to 0.5 mol of the compound (C) is used. 2. The method according to claim 1, characterized in that one uses a polymer (A), which contains based on the total number of Stinktoreinheiten of formula (1) and (2) 0.1 to 40 mol% of structural units of the formula (2) , 3. The method according to at least one of the preceding claims, characterized in that one uses a polymer (A) which contains 0.01 to 70 wt .-% of structural units of the formula (3), which consists of olefins having 2 to 18 carbon atoms, (Meth) acrylic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid, (meth) acrylamides and / or ethylene sulfonic acid derived. 4. The method according to claim 3, characterized in that one uses a polymer (A) which contains structural units of the formula (3) derived from ethylene. 5. The method according to at least one of the preceding claims, characterized in that one uses a hydroxy compound (B), wherein n is a number in the range of 2 and 1000. 6. The method according to at least one of the preceding claims, characterized in that one uses a hydroxy compound (B), wherein R ^{8 is} hydrogen. 7. The method according to at least one of the preceding claims, characterized in that one uses a hydroxy compound (B), wherein each R ⁷ is independently hydrogen or methyl. 8. The method according to at least one of the preceding claims, characterized in that formaldehyde, acetaldehyde, propionaldehyde, n-butyraldehyde, iso-butyraldehyde, 2-ethoxybutyraldehyde, caproic aldehyde, 2-ethylhexanal, pelargonaldehyde, 3,5,5-trimethylhexanal, 2nd -Formylbenzenesulfonic acid, acetone, ethyl methyl ketone, butyl ethyl ketone and / or ethyl hexyl ketone as the compound (C). 9. The method according to at least one of the preceding claims, characterized in that one uses the compounds (B) and (C) in a molar ratio of compound (C) / compound (B) greater than or equal to one. 10. The method according to mindeetens one of the preceding Anβprüche, characterized in that one carries out the reaction in the presence of acidic catalysts. 11. Polyvinyl acetal obtainable by a process according to any one of the preceding claims. 12. polyvinyl acetal according to claim 11 as a sheet. 13. polyvinyl acetal according to claim 12 as a film having a thickness in the range of 0.5 .mu.m to 1 mm. 14. Use of a polyvinyl acetal according to any one of claims 11 to 13 for laminated glass films and adhesives and peelable coatings. 15. Use of a polyvinyl acetal according to claim 11 as a fiber. 16. Foil composite comprising at least one layer of polyvinyl acetal according to at least one of claims 11 to 13. 17. Use of a film composite according to claim 16 for sound insulation.