REDISPERSIBLE POLYMER POWDER COMPOSITIONS WITH IMPROVED IMPACT RESISTANCE

Abstract

The present invention relates to a vinyl ester latex polymer composition, a process for preparing the composition, a water redispersible polymer powder with improved impact resistance obtained therefrom and to the use of the polymer powder for construction applications.

Claims

1. A vinyl ester latex polymer composition, comprising, based on the total amount of monomers, a) from 50 to 99% by weight of vinyl esters of C2-C12-carboxylic acids and from 1% to 50% of acrylic esters, methacrylic esters, maleic esters, ethylene or any other monomer capable of copolymerizing with the said vinyl esters by radical emulsion polymerization, and b) from 0.5% to 10% by weight, based on total amount of monomers, of di- and/or tri-hydroxy alcohols of MW (molecular weight) lower than 500 g/mol and that this component is present during the polymerization process.

2. The latex polymer composition of claim 1 where the hydroxy component is glycerol.

3. The latex polymer composition of claim 1 where the hydroxy component is a glycol of MW less than 250 g/mol.

4. The latex polymer composition of claim 1, wherein the vinyl esters of C2-C12-carboxylic acids are selected from at least one member of the group consisting of vinyl acetate, vinyl propionate, vinyl butyrate, vinyl laurate and vinyl esters of -branched monocarboxylic acids, particularly vinyl 2-ethylhexanoate, 1-methylvinyl acetate and vinyl pivalate.

5. The latex polymer composition of claim 4, wherein the vinyl esters of C2-C12-carboxylic acids are selected from vinyl acetate and/or vinyl esters of -branched monocarboxylic acids.

6. The latex polymer composition of claim 1, wherein the acrylic or methacrylic esters are selected from methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, n-butyl acrylate, tert.-butyl acrylate, n-butyl methacrylate, tert.-butyl methacrylate and/or 2-ethylhexyl acrylate, preferably butyl acrylate and 2-ethyl hexyl acrylate.

7. The latex polymer composition of claim 1, wherein the maleic esters are selected from di-butyl maleate and/or di-octyl maleate.

8. The latex polymer composition of claim 1, wherein said latex polymer further comprises from 0.01 to 5% by weight, based on the total weight of the polymer, of one or more auxiliary monomer units for crosslinking or to modify the adhesion properties,

9. The latex polymer composition of claim 8, wherein the auxiliary monomer unit for crosslinking is derived from N-methylolacrylamide, N-methylolmethacrylamide; N-(alkoxymethyl)acrylamides or N-(alkoxymethyl)methacrylamides containing a C.sub.1-C.sub.6-alkyl radical, including N-(isobutoxymethyl)acrylamide (IBMA), N-(isobutoxymethyl)methacrylamide (IBMMA), N-(n-butoxymethyl)acrylamide (NBMA), N-(n-butoxymethyl)methacrylamide (NBMMA); multiple ethylenically unsaturated comonomers including ethylene glycol diacrylate, 1,3-butylene glycol diacrylate, 1,4-butylene glycol diacrylate, propylene glycol diacrylate, divinyl adipate, divinyl benzene, vinyl methacrylate, vinyl acrylate, allyl methacrylate, allyl acrylate, diallyl maleate, diallyl phthalate, diallyl fumarate, methylenebisacrylamide, cyclopentadienyl acrylate and triallyl cyanurate.

10. The latex polymer composition of claim 8, wherein the auxiliary monomer unit to modify the adhesion properties is derived from hydroxylalkyl methacrylates and hydroxylalkyl acrylates including hydroxyethyl, hydroxypropyl and hydroxybutyl acrylate or methacrylate, diacetone-acrylamide or acetylacetoxyethyl acrylate or methacrylate.

11. The latex polymer composition of claim 1, further comprising one or more protective colloids or emulsifiers or combinations of both in a total amount of from 2 to 40%, more preferably 3 to 15% and most preferably 5 to 10% by weight based on the total weight of the monomers, preferably comprising one or more protective colloids selected from polyvinyl alcohols, polyethylene glycol, polyvinylpyrrolidone, celluloses including hydroxyethylcellulose, hydroxypropylcellulose and carboxymethylcellulose, starches and dextrins, cyclodextrins, and homopolymers or copolymers of acrylamidopropanesulfonic acid.

12. A process for producing the latex polymer composition of claim 1 where the polymerization reaction is carried out by emulsion polymerization in a temperature range from 0 to 100 C. and is initiated by means of water-soluble free-radical initiators used for emulsion polymerization.

13. A water redispersible polymer powder obtainable by spray-drying the latex polymer composition of claim 1.

14. Use of the water redispersible polymer powder as defined in claim 13 as an additive for EPS and XPS boards in ETICS applications.

Description

EXAMPLE 1

[0041] Preparation of Vinyl Acetate/2-Ethylhexyl Acrylate Based Emulsion Polymer with Mono Ethylene Glycol

[0042] A monomix-1 (monomer blend) consisting of 501.96 parts of vinyl acetate and 16.02 parts of 2-ethylhexyl acrylate was prepared. 40 parts of this monomix was set aside (seed monomix) and the rest was placed in a dosing funnel attached to one of the reactor's necks.

[0043] 134 parts of deionized water and 191 parts of polyvinyl alcohol 13/88 (14% solution in DI water) are added to a 3-necked flask equipped with a stirrer, thermometer and a reflux condenser. The flask is heated to 65 C. and the seed monomix is added. 0.49 parts of hydrogen peroxide dissolved in 4.5 parts of deionized water and then 0.21 parts of BruggoliteFF6 and 0.38 parts of sodium bicarbonate dissolved in 11.48 parts of deionized water are introduced. Upon reaction of the seed monomer, the rest of the monomix-1 is fed parallel with 2.59 parts of hydrogen peroxide dissolved in 40 parts of deionized water, and 1.1 parts of BruggoliteFF6 and 2.01 parts of sodium bicarbonate dissolved in 40 parts of deionized water. After 464.58 parts of the monomix-1 have been fed, feeding of 16.02 parts of mono ethylene glycol is started parallel with the monomer mixture. After 3 hours of the reaction which was carried out at 72-75 C., feeds are completed and the resulting polymer dispersion is heated for 30 minutes at 80 C. The reaction temperature is decreased to 70 C. and 0.21 parts of tert.-butyl hydroperoxide dissolved in 10 parts of deionized water is added to the flask. After that, 0.10 parts of BruggoliteFF6 is added dissolved in 10 parts of deionized water. 139 parts of polyvinyl alcohol 3/88 (18% solution in DI water) are introduced. The final latex polymer has a solid content of 48.3%, pH 5.8, viscosity is 800 cps (LVT 3/20), Tg is 30.5 C.

EXAMPLE 1 SD

[0044] Preparation of the Spray-Dried Redispersible Powder of Example 1

[0045] The latex polymer obtained from Example 1 is mixed at 50 C. The liquid emulsion is spray dried in a Niro spray dryer system using an inlet temperature of 140 C. The drying gas is air. To prevent caking of the powder, 10% of kaolin and for water resistance sodium oleate are introduced via other nozzles. The obtained powder is free-flowing, blocking resistant and could easily be stirred into water to give a stable dispersion. Other characteristics of the powder are: ash content: 10.00%, bulk density: 0.590 g/cm.sup.3 particle size: 0.35% over 400 m screen, humidity: 1.00%)

EXAMPLE 2

[0046] Preparation of Vinyl Acetate/2-Ethylhexyl Acrylate Based Emulsion Polymer with Glycerin

[0047] A monomix-2 (monomer blend) consisting of 501.96 parts of vinyl acetate and 16.02 parts of 2-ethylhexyl acrylate was prepared. 40 parts of this monomix was set aside (seed monomix) and the rest was placed in a dosing funnel attached to one of the reactor's necks.

[0048] 134 parts of deionized water and 191 parts of polyvinyl alcohol 13/88 (14% solution in DI water) are added to a 3-necked flask equipped with a stirrer, thermometer and a reflux condenser. The flask is heated to 65 C. and the seed monomix is added. 0.49 parts of hydrogen peroxide dissolved in 4.5 parts of deionized water and then 0.21 parts of BruggoliteFF6 and 0.38 parts of sodium bicarbonate dissolved in 11.48 parts of deionized water are introduced. Upon reaction of the seed monomix, the rest of the monomix-2 is fed parallel with 2.59 parts of hydrogen peroxide dissolved in 40 parts of deionized water, and 1.1 parts of BruggoliteFF6 and 2.01 parts of sodium bicarbonate dissolved in 40 parts of deionized water. After 464.58 parts of the monomer mixture have been fed, feeding of 16.02 parts of glycerin is started parallel with the monomer mixture. After 3 hours of the reaction at 72-75 C., it is heated for 30 minutes at 80 C. The reaction temperature is decreased to 70 C. and 0.21 parts of tert.-butyl hydroperoxide dissolved in 10 parts of deionized water are added to the flask. After that, 0.10 parts of BruggoliteFF6 is added dissolved in 10 parts of deionized water. 139 parts of polyvinyl alcohol 3/88 (18% solution in DI water) is introduced. The final latex polymer has a solid content of 48.3%, pH 5.8, viscosity is 800 cps (LVT 3/20), Tg is 28.5 C.

EXAMPLE 2 SD

[0049] Preparation of the Spray-Dried Redispersible Powder of Example 2

[0050] The latex polymer obtained from Example 2 is mixed at 50 C. The liquid emulsion is spray dried in a Niro spray dryer system using an inlet temperature of 140 C. The drying gas is air. To prevent caking of the powder 10% of kaolin and for water resistance sodium oleate are introduced via other nozzles. The obtained powder is free-flowing, blocking resistant and could easily be stirred into water to give a stable dispersion. Other characteristics of the powder are: ash content: 10.56%, bulk density: 0.591 g/cm.sup.3 particle size: 0.30% over 400 m screen, humidity: 1.03%

COMPARATIVE EXAMPLE 3

[0051] Preparation of Vinyl Acetate/2-Ethylhexyl Acrylate Based Emulsion Polymer without Di- or Tri-Hydroxy Alcohols

[0052] A monomix-3 (monomer blend) consisting of 501.96 parts of vinyl acetate and 16.02 parts of 2-ethylhexyl acrylate was prepared. 40 parts of this monomix was set aside (seed monomix) and the rest was placed in a dosing funnel attached to one of the reactor's necks.

[0053] 134 parts of deionized water and 191 parts of polyvinyl alcohol 13/88 (14% solution in DI water) are added to a 3-necked flask equipped with a stirrer, thermometer and a reflux condenser. The flask is heated to 65 C. and the seed monomix is added. 0.49 parts of hydrogen peroxide dissolved in 4.5 parts of deionized water and then 0.21 parts of BruggoliteFF6 and 0.38 parts of sodium bicarbonate dissolved in 11.48 parts of deionized water are introduced. Upon reaction of the seed monomix, the rest of the monomix-3 is fed parallel with 2.59 parts of hydrogen peroxide dissolved in 40 parts of deionized water, and 1.1 parts of BruggoliteFF6 and 2.01 parts of sodium bicarbonate dissolved in 40 parts of deionized water. After 3 hours of reaction at 72-75 C., it is heated for 30 minutes more at 80 C. The reaction temperature is decreased to 70 C. and 0.21 parts of tert.-butyl hydroperoxide dissolved in 10 parts of deionized water is added to the flask. After that, 0.10 parts of BruggoliteFF6 is added dissolved in 10 parts of deionized water. 139 parts of polyvinyl alcohol 3/88 (18% solution in DI water) is introduced. The final latex polymer has a solid content of 48.0%, pH 5.4, viscosity is 850 cps (LVT 3/20), Tg is 30 C.

COMPARATIVE EXAMPLE 3 SD

[0054] Preparation of the Spray-Dried Redispersible Powder of Example 3

[0055] The latex polymer obtained from Comparative Example 3 is mixed at 50 C. The liquid emulsion is spray dried in a Niro spray dryer using an inlet temperature of 140 C. The drying gas is air. To prevent caking of the powder 10% of kaolin and for water resistance sodium oleate are introduced via other nozzles. The obtained powder is free-flowing, blocking resistant and could easily be stirred into water to give a stable dispersion. Other characteristics of the powder are: ash content: 10.20%, bulk density: 0.592 g/cm.sup.3, particle size: 0.39% over 400 m screen, humidity: 1.03%.

[0056] Application Tests of the Examples in ETICS Plasters

[0057] The EPS test samples were cured at 232 C. and 5010% relative humidity conditions. The application tests of these samples were evaluated according to European test standards. For determination of impact resistance, EN 13497 standard was followed. The tensile bonding strength of the samples was evaluated based on EN 13494. The tensile bonding strength and breaking of EPS surface tests were done in a Zwick Universal Testing machine. In addition to these, the determination of water absorption coefficient due to capillary action of the cured mortars was also evaluated according to EN 1015-18 standard (Table 1).

[0058] It can be easily observed that the impact resistance of the building materials were remarkably improved in Examples 1 SD and 2 SD when compared to Comparative Example 3 SD where neither di- nor tri-hydroxy alcohol was used. In addition to impact resistance, the tensile bonding strength, breaking up of EPS surface is significantly improved while the use of the water soluble MEG and glycerol did not have any detrimental effect on water absorption of the cured mortar samples.

TABLE-US-00001 TABLE-1 Application test results of the samples in ETICS applications Internal References Comparative (Ref. A) Example Example Example VAM/2EHA + (Ref. B) (Ref. C) Application Tests 1 SD 2 SD 3 SD 0.5% Benzoflex VAM/2EHA VAM/VeoVa Measured Tg ( C.) 30.5 28.5 30.0 29.5 3.0 21 Tensile bond strength 85 k/Pa 83 k/Pa 68.66 k/Pa 83 k/Pa 81 k/Pa 56.16 k/Pa on EPS after 28 days (min 80 k/Pa) Breaking of EPS 100% 100% 0% 100% 100% 0% surface after 7 days (min 40%) Breaking of EPS 100% 100% 0% 100% 100% 0% surface after 14 days (min 40%) Breaking of EPS 100% 100% 0% 100% 100% 0% surface after 28 days (min 40%) Impact resistance good (no good (no poor (cracks poor (cracks poor (cracks poor (cracks after 3 days cracks) cracks) observed) observed) observed) observed) Impact resistance good (no good (no poor (cracks poor (cracks poor (cracks poor (cracks after 7 days cracks) cracks) observed) observed) observed) observed) Impact resistance good (no good (no poor (cracks poor (cracks poor (cracks poor (cracks after 14 days cracks) cracks) observed) observed) observed) observed) Impact resistance good (no good (no poor (cracks poor (cracks poor (cracks poor (cracks after 28 days cracks) cracks) observed) observed) observed) observed) water absorption 0.1 0.05 0.07 0.5 0.11 0.08 (0.5 kg/m2; min 0.5)

[0059] In the left column of the table the minimum values are indicated which are the minimum values to be considered acceptable in accordance with the norms cited hereinabove as the standard norms for evaluating each of the properties compared in this table.

[0060] The three internal references on the table illustrate the counterintuitive improvement in impact resistance effected by the present invention.

[0061] Ref A is a powder based on a similar composition, comparable Tg and similar bonding strength onto EPS as Examples 1 SD and 2 SD. The impact resistance is remarkably lower than that of Examples 1 SD and 2 SD even though it has been helped by post-addition with plasticizer (Benzoflex) to improve its flexibility.

[0062] Ref B is a powder based on a similar monomer composition but using a much higher ratio of 2EHA in order to dramatically increase flexibility and induce softness, resulting in a much lower Tg (about 25 C. lower). Although the powder compound shows good flexibility and bonding strength onto EPS, it could not pass the impact resistance test as Examples 1 SD and 2 SD do.

[0063] Ref C is a typical VAM/VeoVa composition of Tg around 20 C. Despite the fact that its Tg is lower than that of Examples 1 SD and 2 SD, it did not pass the impact resistance test and showed a much poorer adhesion performance onto EPS.

[0064] Taking the above results into account, it is an extra advantage to be able to obtain good impact resistance with relatively high Tg. Particularly in ETICS application (exterior) soft polymers or plasticized ones tend to show a reduced mineral pigments and fillers binding power along with a remarkable tendency to pick up dirt.

COMPARATIVE EXAMPLES 4 AND 5

[0065] Further comparative examples were carried out to demonstrate that polyetherdiols as used in U.S. Pat. No. 4,542,182 do not result at all in the same or similar technical effect as the present invention, i.e. to provide a comparison between glycols (dihydroxyalcohols) and so-called polyethylene glycols (PEG's, polyethylene oxide or polyetherdiols).

[0066] Two commercially available polyethylene glycols from BASF (Pluriol E 1000) and CLARIANT (polyglykol-400) were selected. PEG-400, with an average molecular weight of 400 g/mol, falling within the MW<500 g/mol criteria for the di- and tri-hydroxy alcohols in accordance with the present invention, and PEG-1000, with an average molecular weight of 1000 g/mol, that falls outside that MW<500 g/mol criteria.

[0067] These comparative examples were run using PEG-400 and PEG-1000 in parallel with Example 1 given hereinabove. Moreover, since in accordance with the present invention the di- and/or tri-hydroxy component are present during the polymerization process, each comparative example using PEG has been doubled in order to cover all possible ways, resulting in two versions (A) and (B). In version A, PEG is used late with the monomer feeding as in Example 1, whereas in version B, it is added into the reactor before monomer feeding starts.

[0068] The following examples and the corresponding impact resistance results clearly demonstrate that polyethylene oxide (under the name polyethylene glycol, PEG, or whichever) does not have the same technical effect as the present invention irrespective of whether it has smaller or greater molecular weight than 500 g/mol.

COMPARATIVE EXAMPLE 4-(A) WITH PEG-400

[0069] Preparation of Vinyl Acetate/2-Ethylhexyl Acrylate Based Emulsion Polymer with Polyethylene Glycol with an Average Molecular Weight of 400 g/mol (A)

[0070] The procedure of Example 1 herein above was repeated with the exception that polyethylene glycol with a molecular weight of 400 g/mol was used instead of ethylene glycol.

[0071] A monomix-4 (monomer blend) consisting of 501.96 parts of vinyl acetate and 16.02 parts of 2-ethylhexyl acrylate was prepared. 40 parts of this monomix was set aside (seed monomix) and the rest was placed in a dosing funnel attached to one of the reactor's necks. 134 parts of deionized water and 191 parts of polyvinyl alcohol 13/88 (14% solution in DI water) were added to a 3-necked flask equipped with a stirrer, thermometer and a reflux condenser. The flask was heated to 65 C. and the seed monomix was added. 0.49 parts of hydrogen peroxide dissolved in 4.5 parts of deionized water and then 0.21 parts of BruggoliteFF6 and 0.38 parts of sodium bicarbonate dissolved in 11.48 parts of deionized water were introduced. Upon reaction of the seed monomer, the rest of the monomix-4 was fed parallel with 2.59 parts of hydrogen peroxide dissolved in 40 parts of deionized water, and 1.1 parts of BruggoliteFF6 and 2.01 parts of sodium bicarbonate dissolved in 40 parts of deionized water. After 464.58 parts of the monomix-4 has been fed, feeding of 16.02 parts of PEG-400 (polyethylene glycol with a molecular weight of 400 g/mol) was started parallel with monomer mixture. After 3 hours of the reaction which was carried out at 72-75 C., feeds were completed and the resulting polymer dispersion was heated for 30 minutes at 80 C. The reaction temperature was decreased to 70 C. and 0.21 parts of tert.-butyl hydroperoxide dissolved in 10 parts of deionized water was added to the flask. After that, 0.10 parts of BruggoliteFF6 was added as dissolved in 10 parts of deionized water. 139 parts of polyvinyl alcohol 3/88 (18% solution in DI water) was introduced. The final latex polymer has a solid content of 49.8%, pH 5.1, viscosity is 220 cps (LVT 3/60), Tg is 27 C.

COMPARATIVE EXAMPLE-4 SD-(A)

[0072] Preparation of the Spray-Dried Redispersible Powder of Comparative Example 4 with PEG-400-(A)

[0073] The procedure of Example 1 SD given herein above was repeated with Comparative Example 4 using PEG-400-(A).

[0074] The latex polymer obtained from Comparative Example-4 with PEG-400-(A) was mixed at 50 C. The liquid emulsion was spray dried in a Niro spray dryer system using an inlet temperature of 140 C. The drying gas was air. To prevent caking of the powder, 10% kaolin and for water resistance sodium oleate were introduced via other nozzles. The obtained powder was free-flowing, blocking resistant and could easily be stirred into water to give a stable dispersion. Other characteristics of the powder are: ash content: 10.0%, bulk density: 0.591 g/cm.sup.3, particle size: 0.35% over 400 m screen, humidity: 1.00%

COMPARATIVE EXAMPLE-4-(B) WITH PEG-400

[0075] Preparation of Vinyl Acetate/2-Ethylhexyl Acrylate Based Emulsion Polymer with Polyethylene Glycol with a Molecular Weight of 400 g/mol (B)

[0076] The procedure of Comparative Example 4-(A) with PEG-400 was repeated with the exception that polyethylene glycol with a molecular weight of 400 g/mol was used in reactor pre-charge instead of feeding it parallel to the monomer mixture.

[0077] A monomix-4 (monomer blend) consisting of 501.96 parts of vinyl acetate and 16.02 parts of 2-ethylhexyl acrylate was prepared. 40 parts of this monomix was set aside (seed monomix) and the rest was placed in a dosing funnel attached to one of the reactor's necks.

[0078] 134 parts of deionized water, 191 parts of polyvinyl alcohol 13/88 (14% solution in DI water) and 16.02 parts of PEG-400 (polyethylene glycol with a molecular weight of 400 g/mol) were added to a 3-necked flask equipped with a stirrer, thermometer and a reflux condenser. The flask was heated to 65 C. and the seed monomix was added. 0.49 parts of hydrogen peroxide dissolved in 4.5 parts of deionized water and then 0.21 parts of BruggoliteFF6 and 0.38 parts of sodium bicarbonate dissolved in 11.48 parts of deionized water were introduced. Upon reaction of the seed monomer, the rest of the monomix-4 was fed parallel with 2.59 parts of hydrogen peroxide dissolved in 40 parts of deionized water, and 1.1 parts of BruggoliteFF6 and 2.01 parts of sodium bicarbonate dissolved in 40 parts of deionized water. After 3 hours of the reaction which was carried out at 72-75 C., feeds were completed and the resulting polymer dispersion was heated for 30 minutes at 80 C. The reaction temperature was decreased to 70 C. and 0.21 parts of tert.-butyl hydroperoxide dissolved in 10 parts of deionized water were added to the flask. After that, 0.10 parts of BruggoliteFF6 were added as dissolved in 10 parts of deionized water. 139 parts of polyvinyl alcohol 3/88 (18% solution in DI water) was introduced. The final latex polymer has a solid content of 50.2%, pH 5.1, viscosity is 260 cps (LVT 3/60), Tg is 26.5 C.

COMPARATIVE EXAMPLE-4 SD-(B)

[0079] Preparation of the Spray-Dried Redispersible Powder of Comparative Example 4-(B) with PEG-400

[0080] The procedure of Example 1 SD given herein above was repeated with Comparative Example 4-(B) using PEG-400.

[0081] The latex polymer obtained from Comparative Example-4 with PEG-400-(B) was mixed at 50 C. The liquid emulsion was spray dried in a Niro spray dryer system using an inlet temperature of 140 C. The drying gas was air. To prevent caking of the powder, 10% kaolin and for water resistance sodium oleate were introduced via other nozzles. The obtained powder was free-flowing, blocking resistant and could easily be stirred into water to give a stable dispersion. Other characteristics of the powder are: ash content: 10.0%, bulk density: 0.591 g/cm.sup.3, particle size: 0.35% over 400 m screen, humidity: 1.00%

COMPARATIVE EXAMPLE 5-(A) WITH PEG-1000

[0082] Preparation of Vinyl Acetate/2-Ethylhexyl Acrylate Based Emulsion Polymer with Polyethylene Glycol with a Molecular Weight of 1000 g/mol (A)

[0083] The procedure of Example 1 given herein above was repeated with the exception that polyethylene glycol with a molecular weight of 1000 g/mol was used instead of ethylene glycol.

[0084] A monomix-5 (monomer blend) consisting of 501.96 parts of vinyl acetate and 16.02 parts of 2-ethylhexyl acrylate was prepared. 40 parts of this monomix was set aside (seed monomix) and the rest was placed in a dosing funnel attached to one of the reactor's necks.

[0085] 134 parts of deionized water and 191 parts of polyvinyl alcohol 13/88 (14% solution in DI water) were added to a 3-necked flask equipped with a stirrer, thermometer and a reflux condenser. The flask was heated to 65 C. and the seed monomix was added. 0.49 parts of hydrogen peroxide dissolved in 4.5 parts of deionized water and then 0.21 parts of BruggoliteFF6 and 0.38 parts of sodium bicarbonate dissolved in 11.48 parts of deionized water were introduced. Upon reaction of the seed monomer, the rest of the monomix-5 was fed parallel with 2.59 parts of hydrogen peroxide dissolved in 40 parts of deionized water, and 1.1 parts of BruggoliteFF6 and 2.01 parts of sodium bicarbonate dissolved in 40 parts of deionized water. After 464.58 parts of the monomix-5 had been fed, feeding of 16.02 parts of PEG-1000 (polyethylene glycol with a molecular weight of 1000 g/mol) was started parallel with monomer mixture (since it is solid at room temperature, it has been melted beforehand in order to feed in liquid form). After 3 hours of the reaction which was carried out at 72-75 C., feeds were completed and the resulting polymer dispersion was heated for 30 minutes at 80 C. The reaction temperature was decreased to 70 C. and 0.21 parts of ter.-butyl hydroperoxide dissolved in 10 parts of deionized water was added to the flask. After that, 0.10 parts of BruggoliteFF6 was added as dissolved in 10 parts of deionized water. 139 parts of polyvinyl alcohol 3/88 (18% solution in DI water) was introduced. The final latex polymer has a solid content of 49.8%, pH 5.1, viscosity is 270 cps (LVT 3/60), Tg is 27 C.

COMPARATIVE EXAMPLE-5 SD-(A)

[0086] Preparation of the Spray-Dried Redispersible Powder of Comparative Example 5-(A) with PEG-1000

[0087] The procedure of Example 1 SD given herein above was repeated with Comparative Example 5-(A) using PEG-1000.

[0088] The latex polymer obtained from Comparative Example-5-(A) with PEG-1000 was mixed at 50 C. The liquid emulsion is spray dried in a Niro spray dryer system using an inlet temperature of 140 C. The drying gas was air. To prevent caking of the powder, 10% kaolin and for water resistance sodium oleate were introduced via other nozzles. The obtained powder was free-flowing, blocking resistant and could easily be stirred into water to give a stable dispersion. Other characteristics of the powder are: ash content: 10.0%, bulk density: 0.591 g/cm.sup.3, particle size: 0.35% over 400 m screen, humidity: 1.00%

COMPARATIVE EXAMPLE 5-(B) WITH PEG-1000

[0089] Preparation of Vinyl Acetate/2-Ethylhexyl Acrylate Based Emulsion Polymer with Polyethylene Glycol with a Molecular Weight of 1000 g/mol (B)

[0090] The procedure of comparative Example 5-(A) with PEG-1000 was repeated with the exception that polyethylene glycol with a molecular weight of 1000 g/mol was used in reactor pre-charge, instead of feeding it parallel to the monomer mixture.

[0091] A monomix-5 (monomer blend) consisting of 501.96 parts of vinyl acetate and 16.02 parts of 2-ethylhexyl acrylate was prepared. 40 parts of this monomix was set aside (seed monomix) and the rest was placed in a dosing funnel attached to one of the reactor's necks.

[0092] 134 parts of deionized water, 191 parts of polyvinyl alcohol 13/88 (14% solution in DI water) and 16.02 parts of PEG-1000 (polyethylene glycol with a molecular weight of 1000 g/mol) were added to a 3-necked flask equipped with a stirrer, thermometer and a reflux condenser. The flask was heated to 65 C. and the seed monomix was added. 0.49 parts of hydrogen peroxide dissolved in 4.5 parts of deionized water and then 0.21 parts of BruggoliteFF6 and 0.38 parts of sodium bicarbonate dissolved in 11.48 parts of deionized water were introduced. Upon reaction of the seed monomer, the rest of the monomix-5 was fed parallel with 2.59 parts of hydrogen peroxide dissolved in 40 parts of deionized water, and 1.1 parts of BruggoliteFF6 and 2.01 parts of sodium bicarbonate dissolved in 40 parts of deionized water. After 3 hours of the reaction which was carried out at 72-75 C., feeds were completed and the resulting polymer dispersion was heated for 30 minutes at 80 C. The reaction temperature was decreased to 70 C. and 0.21 parts of ter.-butyl hydroperoxide dissolved in 10 parts of deionized water was added to the flask. After that, 0.10 parts of BruggoliteFF6 was added as dissolved in 10 parts of deionized water. 139 parts of polyvinyl alcohol 3/88 (18% solution in DI water) was introduced. The final latex polymer has a solid content of 49.8%, pH 5.1, viscosity is 270 cps (LVT 3/60), Tg is 28 C.

COMPARATIVE EXAMPLE-5 SD-(B)

[0093] Preparation of the Spray-Dried Redispersible Powder of Comparative Example 5-(B) with PEG-1000

[0094] The procedure of Example 1 SD given herein above was repeated with Comparative Example 5-(B) using PEG-1000.

[0095] The latex polymer obtained from Comparative Example-5-(B) with PEG-1000 was mixed at 50 C. The liquid emulsion was spray dried in a Niro spray dryer system using an inlet temperature of 140 C. The drying gas was air. To prevent caking of the powder, 10% kaolin and for water resistance sodium oleate were introduced via other nozzles. The obtained powder was free-flowing, blocking resistant and could easily be stirred into water to give a stable dispersion. Other characteristics of the powder are: ash content: 10.2%, bulk density: 0.589 g/cm.sup.3, particle size: 0.35% over 400 m screen, humidity: 1.01%

[0096] Impact Resistance Test Results of the Examples in ETICS Plasters:

[0097] The EPS test samples were cured at 232 C. and 5010% relative humidity conditions. The impact resistance test was done according to EN 13497.

TABLE-US-00002 TABLE 1 Impact resistance test results of the comparative examples which contain different types of PEG Comparative Comparative Comparative Comparative Example-4 SD- Example-4 SD- Example-5 SD- Example-5 Application Example 1 (A) with (B) with (A) with SD-(B) with Tests SD PEG-400 PEG-400 PEG-1000 PEG-1000 Measured Tg ( C.) 30.5 27 26.5 27 28 Impact resistance good (no poor poor poor poor after 3 days cracks) (cracks observed) (cracks observed) (cracks observed) (cracks observed) Impact resistance good (no poor poor poor poor after 7 days cracks) (cracks observed) (cracks observed) (cracks observed) (cracks observed)

[0098] Many variations of the present invention can be made without departing from the scope of its teachings. The specific embodiments and examples described here are offered as a way of illustrating and making more comprehensible the present application.