CROSSLINKABLE POLYMER-POWDER COMPOSITIONS REDISPERSIBLE IN WATER

Abstract

A crosslinkable polymer powder compositions redispersible in water includes one or more vinyl ester polymers, one or more compounds bearing epoxide groups and optionally one or more curing agents which crosslink with the compounds bearing epoxide groups. The vinyl ester polymers do not comprise any epoxide-functional monomer units. The crosslinkable polymer powder compositions redispersible in water includes ≥51% by weight, based on the total weight of the vinyl ester polymers, of one or more compounds bearing epoxide groups.

Claims

1-11. (canceled)

12. A crosslinkable polymer powder composition redispersible in water, comprising: one or more protective colloid-stabilized vinyl ester polymers; one or more compounds bearing epoxide groups; and optionally one or more curing agents which crosslink with the compounds bearing epoxide groups, wherein the vinyl ester polymers do not comprise any epoxide-functional monomer units, and the crosslinkable polymer powder compositions redispersible in water comprise ≥51% by weight, based on the total weight of the vinyl ester polymers, of one or more compounds bearing epoxide groups and mixtures of the protective colloid-stabilized vinyl ester polymers and the compounds bearing epoxide groups have glass transition temperatures Tg of −40° C. to +20° C., determined by differential scanning calorimetry.

13. The crosslinkable polymer powder composition of claim 12, wherein one or more epoxy resins are present as compounds bearing epoxide groups.

14. The crosslinkable polymer powder composition of claim 12, wherein 55 to 300% by weight of compounds bearing epoxide groups are present, based on the total weight of the vinyl ester polymers.

15. The crosslinkable polymer powder composition of claim 12, wherein that 20 to 75% by weight of compounds bearing epoxide groups are present, based on the total weight of the crosslinkable polymer powder compositions redispersible in water.

16. The crosslinkable polymer powder composition of claim 12, wherein one or more vinyl ester polymers are based on ≥50% by weight of vinyl esters, based on the total weight of the vinyl ester polymers.

17. The crosslinkable polymer powder composition of claim 12, wherein one or more vinyl ester polymers are selected from the group comprising vinyl ester homopolymers, copolymers of vinyl acetate with ethylene, copolymers of vinyl acetate with ethylene and one or more further vinyl esters, copolymers of one or more vinyl esters, vinyl chloride and ethylene and copolymers of vinyl acetate with ethylene and one or more acrylic esters.

18. The crosslinkable polymer powder composition of claim 12, wherein 15 to 75% by weight of vinyl ester polymers are present, based on the total weight of the crosslinkable polymer powder compositions.

19. The crosslinkable polymer powder composition of claim 12, wherein the crosslinkable polymer powder composition has a glass transition temperature Tg in the range of −40° C. to +20° C., determined by differential scanning calorimetry, and the plot for determining the glass transition temperature Tg only has one maximum.

20. A process for producing the crosslinkable polymer powder composition of claim 12, comprising: polymerizing one or more vinyl esters by means of free-radically initiated emulsion polymerization or suspension polymerization in water and then drying thereof, wherein ≥51% by weight, based on the total weight of the vinyl esters, of compounds bearing epoxide groups are added before or during the polymerization or before or during drying.

21. The process of claim 20, wherein one or more compounds bearing epoxide groups are added wholly or partially during or after post-polymerization or wholly or partially after completion of the polymerization or wholly or partially before drying.

22. The use of the crosslinkable polymer powder composition of claim 12 in construction chemical products selected from the group comprising tile adhesives, integrated thermal insulation adhesives, renders, spackling compounds, steam barriers, levelling compounds, sealing slurries, jointing mortars, repair mortars and paints or in coatings or binders for woven and nonwoven textiles and paper.

Description

THE FOLLOWING EXAMPLES SERVE TO FURTHER ELUCIDATE THE INVENTION

Production of Aqueous Dispersions Based on Polymers and Epoxy Resins

Example 5

[0074] 125 kg of an aqueous dispersion of a polyvinyl alcohol-stabilized vinyl acetate-ethylene copolymer (Tg of 14.1° C.; solids content of 58.0%) were initially charged in a reactor of 400 L volume and heated to 70° C. with stirring at 60 rpm.

[0075] Then 88.6 kg of the epoxy resin Epilox F17-00 were metered in over 15 minutes. The dispersion thus obtained comprised 55% by weight epoxy resin, based on the dry weight of vinyl acetate-ethylene copolymer and epoxy resin.

Examples 1˜4, Examples 6˜11 and Comparative Examples 1˜3

[0076] The dispersions were prepared analogously to Example 5, but with the provisions of Table 1.

[0077] Determination of Glass Transition Temperatures Tg for Dispersions or Polymer Powders Based on Polymers and Epoxy Resin:

[0078] The glass transition temperatures Tg were determined in accordance with DIN-EN-ISO 11357-2.

[0079] A film was produced from the respective dispersion at room temperature overnight. The film was dried under vacuum for 24 hours at room temperature and stored under nitrogen; the glass transition temperature Tg was then determined.

[0080] To determine the glass transition temperature Tg on the basis of a powder, the relevant powder was dried under vacuum for 24 hours at room temperature; the glass transition temperature Tg was then determined.

TABLE-US-00001 TABLE 1 Dispersions based on polymers and epoxy resin: Tg.sup.b) Epoxy resin Polymer.sup.a) [° C.] Epoxy resin.sup.c) content.sup.d) [wt. %] Ex.1 VAE −7.1 Epilox F17-00 55 Ex.2 VAE −7.1 Epilox F17-00 66 Ex.3 VAE −7.1 Araldite GY776 55 Ex.4 VAE −7.1 Araldite GY776 66 Ex.5 VAE 14.1 Epilox F17-00 55 Ex.6 VAE 14.1 Epilox F17-00 66 Ex.7 VAE 14.1 Araldite GY776 55 Ex.8 VAE 14.1 Araldite GY776 66 Ex.9 VAE 20.4 Epilox F17-00 50 Ex.10 VAE 20.4 Epilox F17-00 60 Ex.11 VAc 37 Epilox F17-00 57 CEx.1 Sty/BA 36.1 Epilox F17-00 38 CEx.2 Sty/BA 36.1 Araldite GY250 55 CEx.3 Sty/BA −15 Epilox F17-00 50 .sup.a)VAE: vinyl acetate-ethylene copolymer; VAc: vinyl acetate homopolymer; Sty/BA: styrene-butyl acrylate copolymer; .sup.b)Glass transition temperature Tg of the polymers; .sup.c)Epilox F17-00: bisphenol F type, glass transition temperature Tg: −31.7° C., trade name of Leuna Harze; Araldite GY776: bisphenol A type, glass transition temperature Tg: −23.1° C., trade name of Huntsman; Araldite GY250: bisphenol A type, trade name of Huntsman; .sup.d)% by weight epoxy resin, based on the dry weight of polymer and epoxy resin.

[0081] Investigation of the Stability of the Dispersions Based on Polymers and Epoxy Resin:

[0082] The stability of the dispersions was assessed on the basis of their tendency to phase separation using the following qualitative criteria: [0083] Note 1:

[0084] no phase separation after 72 hours' storage at room temperature; [0085] Note 2:

[0086] extensive phase separation after less than 24 hours at room temperature; [0087] Note 3:

[0088] extensive phase separation after less than 12 hours at room temperature.

[0089] This test is also used to assess whether the dispersions are suitable for spray drying for the production of powders. Dispersions rated 1 are required for spray drying.

[0090] Discussion of the Stability and the Glass Transition Temperatures Tg of the Dispersions of the (Comparative) Examples:

[0091] The glass transition temperatures Tg and the assessment of the stability of the dispersions of Examples 1-11 and Comparative examples 1-3 are summarized in Table 2.

[0092] The dispersions of inventive Examples 1-11 with vinyl ester polymers gave only one glass transition, whereas the non-inventive Comparative examples 1-3 with styrene-butyl acrylate copolymers resulted in at least two glass transitions.

[0093] Testing the stability of the dispersions showed that the styrene acrylate polymer dispersions with high epoxy resin contents according to the invention are so unstable that they are not suitable for spray drying—in contrast to the inventive vinyl ester polymer dispersions of the Examples, which are characterized by high stability.

TABLE-US-00002 TABLE 2 Glass transition temperatures Tg and stability of the dispersions: Glass transition temperature Tg [° C.] Glass transition Stability Ex.1 −17.3 single stage 1 Ex.2 −19.0 single stage 1 Ex.3 −16.5 single stage 1 Ex.4 −18.3 single stage 1 Ex.5 −11.1 single stage 1 Ex.6 −15.9 single stage 1 Ex.7 −9.4 single stage 1 Ex.8 −14.5 single stage 1 Ex.9 −8.7 single stage 1 Ex.10 −14.3 single stage 1 Ex.11 −7.9 single stage 1 CEx.1 −10.8/−7.1 multi-stage 2 CEx.2 −14.3/−0.9 multi-stage 3 CEx.3 −21.6/−6.3 multi-stage 3

[0094] Particle Sizes of Polymers in Dispersions:

[0095] The dispersions of Examples 12-16 and Comparative examples 4-6 were prepared analogously to Example 5, but with the provisions of Table 3.

[0096] The weight-average particle diameter Dw of the respective polymer dispersion Dw(D1) and of the respective dispersion Dw(D2) comprising polymers and epoxy resin were determined (determination method: Coulter LS 1320).

[0097] The quotient of Dw(D2)/Dw (D1) is an indicator of the homogeneity and stability of the dispersion comprising polymers and epoxy resin.

[0098] For a dispersion to be particularly suitable for spray drying, the quotient of Dw(D2)/Dw(D1) should preferably be ≤2.5.

[0099] Higher ratios can indicate inhomogeneity and instability of the dispersion.

[0100] Table 3 summarizes the results. Comparative examples 4-6 show that the aforementioned criterion for the quotient Dw(D2)/Dw (D1) is not met with styrene acrylate polymers and epoxy resin contents according to the invention—in contrast to the dispersions according to the invention with vinyl ester polymers.

TABLE-US-00003 TABLE 3 Dispersions based on polymers and epoxy resin: Epoxy resin Dw.sup.e) Tg.sup.b) content.sup.d) [μm] Dw(D2)/ Polymer.sup.a) [° C.] Epoxy resin.sup.c) [wt %] D1 D2 Dw(D1) CEx. 4 Sty/BA 36.1 Araldite GY250 55 2.2 11.6 5.27 CEx. 5 Sty/BA 20.5 Epilox F17-00 55 3.1 26.3 8.5 CEx. 6 Sty/BA 14 Epilox F17-00 55 2.2 21.8 9.9 Ex. 12 VAc 37 Epilox F17-00 66 1.3 2.8 2.2 Ex. 13 VAE 14.1 Epilox F17-00 66 1.1 2.2 2.0 Ex. 14 VAE 14.1 Araldite GY776 66 1.1 1.7 1.5 Ex. 15 VAE 14.1 Epilox F17-00 55 1.1 1.7 1.5 Ex. 16 VAE 14.1 Araldite GY776 55 1.1 1.9 1.7 .sup.a)VAE: vinyl acetate-ethylene copolymer; VAc: vinyl acetate homopolymer; Sty/BA: styrene-butyl acrylate copolymer; .sup.b)Glass transition temperature Tg of the polymers; .sup.c)Epilox F17-00: bisphenol F type, glass transition temperature Tg: −31.7° C., trade name of Leuna Harze; Araldite GY776: bisphenol A type, glass transition temperature Tg: −23.1° C., trade name of Huntsman; Araldite GY250: bisphenol A type, trade name of Huntsman; .sup.d)% by weight of epoxy resin, based on dry weight of polymer and epoxy resin; .sup.e)Dw: weight-average particle diameters determined using Coulter LS 1320; D1: Polymer dispersion; D2: Dispersion based on polymer and epoxy resin.

Production of Crosslinkable Redispersible Powders (DPP) According to the Invention

Example 17

[0101] In a reactor of 10 L volume, 2000 g of a 58% aqueous polyvinyl alcohol-stabilized dispersion of a vinyl acetate homopolymer (glass transition temperature Tg 37° C.) were homogenized for 2 hours at 70° C. with 1856 g of the epoxy resin Araldite GY250 (bisphenol A type, trade name of Huntsman).

[0102] After cooling to 40° C., 452 g of a 20% aqueous polyvinyl alcohol solution (Hoppler viscosity of 4 mPas, degree of hydrolysis of 88%) and 1856 g of an 11% aqueous polyvinyl alcohol solution (Hoppler viscosity of 13 mPas, degree of hydrolysis of 88%) were added. To this were also added 7.5 g of the defoamer Surfynol MD20 (trade name of APCI) and 22.6 g of the defoamer Foamstar SI 2213 (based on mineral oil/silicone oil; trade name of BASF).

[0103] The dispersion thus obtained had a solids content of 53.7% and a viscosity of 180 mPas (Brookfield 20 RMP, 23° C., spindle 1) and was dried in a cocurrent dryer using a compressed air atomizer at an input temperature of 135° C. and an output temperature of 85° C. with metered addition of 2.5% by weight kaolin, based on organic constituents, as an antiblocking agent.

[0104] This gave 2968 g of a colorless, free-flowing powder redispersible in water. The powder was mixed with 10% by weight kaolin, based on organic constituents, as an antiblocking agent. The powder comprised 50% by weight epoxy resin and 31% by weight vinyl acetate homopolymer, which corresponds to a proportion of 161.3% by weight epoxy resin, based on vinyl acetate homopolymer.

Comparative Example 7

[0105] An aqueous, polyvinyl alcohol-stabilized dispersion of a styrene-butyl acrylate copolymer was used (glass transition temperature Tg: 20.5° C.; solids content 52%); otherwise,

[0106] Comparative example 7 was carried out analogously to Example 17.

[0107] A homogeneous, free-flowing powder could not be obtained.

[0108] This shows that redispersible polymer powders having a high epoxy resin content are not achievable using styrene-butyl acrylate copolymers.

Examples 18-21 and Comparative Example 8

[0109] The crosslinkable redispersion powders of Examples 18-21 and Comparative example 8 were prepared analogously to Example 17, but with the provisions of Table 4.

TABLE-US-00004 TABLE 4 Crosslinkable redispersion powders based on polymers and epoxy resin: Tg.sup.b) Epoxy resin Polymer.sup.a) [° C.] Epoxy resin.sup.c) content.sup.d) [wt. %] Ex.17 VAc 37 Araldite GY250 61 Ex.18 VAc 37 Epilox F17-00 61 Ex.19 VAc 37 Epilox F17-00 61 Ex.20 VAE 14.1 Epilox F17-00 61 Ex.21 VAE −7.0 Epilox F17-00 61 CEx.8 Sty/BA 20.5 Epilox F17-00 23 .sup.a)VAc: vinyl acetate homopolymer; VAE: vinyl acetate-ethylene copolymer; Sty/BA: styrene-butyl acrylate copolymer; .sup.b)Glass transition temperature Tg of the polymers; .sup.c)Epilox F17-00: bisphenol F type, glass transition temperature Tg: −31.7° C., trade name of Leuna Harze; Araldite GY250: bisphenol A type, trade name of Huntsman; .sup.d)% by weight epoxy resin, based on the dry weight of polymer and epoxy resin.

[0110] Discussion of the Crosslinkable Redispersible Powders (DPP):

[0111] Comparative example 8 shows that crosslinkable redispersion powders are achievable with styrene acrylate polymers provided that the epoxy resin content is low.

[0112] In contrast, crosslinkable redispersion powders based on styrene acrylate polymers and a higher proportion of epoxy resin were not achievable, as shown above with Comparative example 7.

TABLE-US-00005 TABLE 5 Glass transition temperatures Tg and stability of the powders of the (comparative) examples: Glass transition temperature Tg [° C.] Glass transition Ex.17 −6.1 single stage Ex.18 −9.8 single stage Ex.19 −8.8 single stage Ex.20 −11.5 single stage Ex.21 −18.2 single stage CEx.8 +2.0 single stage

[0113] Crosslinkable redispersion powders with high proportions of epoxy resin were achievable using vinyl ester polymers (Examples 17-21). The crosslinkable redispersion powders according to the invention (Examples 17-21) all show single-stage glass transitions, as shown in Table 5.

[0114] Cement-Free Mortar Formulation and Testing Thereof:

[0115] The formulations of the cement-free mortar formulations are specified in Table 6. The crosslinkable redispersion powders of Example 18 and Comparative example 8 described above were used as redispersion powders (DPP).

[0116] In the cement-free mortar formulation of Comparative example 11, the redispersion powder CEx.9 was used. The redispersion powder CEx.9 corresponded to Example 18, with the difference that it did not comprise any epoxy resin.

TABLE-US-00006 TABLE 6 Formulations of cement-free mortar formulations: Ex.22 CEx.10 CEx.11 [Wt. %] [Wt. %] [Wt. %] Redispersion powder Ex.18 120.0 CEx.8 162 CEx.9 200 Aradur 3965 .sup.a) 78 69.1 Melflux 6681F .sup.b) 0.6 0.6 0.6 Quartz sand 12 .sup.c) 604.8 604.8 578.02 Quartz sand F .sup.32 d) 225.4 225.4 215.38 Natrosol 250 GR .sup.e) 2.1 2.1 2.0 Refined hydrated lime .sup.f) 4.2 4.2 4.0 Water (total) 145 145 145 .sup.a) Aradur 3965: aqueous solution (55%), trade name of Huntsman, curing agent; .sup.b) Dispersant, trade name of BASF; .sup.c) Filler, sieve line 0.06-0.2; .sup.d) Filler, sieve line 0.24; .sup.e) Hydroxyethyl cellulose, trade name of Ashland, thickener; .sup.f) Ca(OH).sub.2, accelerator.

[0117] The cement-free mortar formulations were produced by first combining and homogenizing the powder components in a laboratory mixer.

[0118] The curing component Aradur 3965 was added with the mixing water.

[0119] The mortar was mixed for one minute with a dissolver with a 6 cm toothed ring at 2000 rpm. After a resting time of 2 minutes, the mixture was stirred for 15 seconds and placed in shuttering molds. Prisms of dimensions 2*2*4 cm were obtained.

[0120] The test specimen from Example 22 could be demolded after just 1 day at room temperature, in contrast the test specimen from Comparative example 11 only after 2 days at room temperature.

[0121] The test specimen from Comparative example 10 could not be demolded non-destructively even after 12 days at room temperature, so that determination of the pressure resistance was impossible.

[0122] The test specimen from Example 22 showed a significantly higher pressure resistance than the test specimen from Comparative example 11. The pressure resistance was determined on the basis of the test specimens in accordance with DIN EN 12808 Part 3 using 2*2*4 cm prisms. The pressure resistance value relates to the corrected contact area. The test results are summarized in Table 7 (column “after RT curing”).

TABLE-US-00007 TABLE 7 Test results of test specimens based on cement-free mortar formulations: Pressure resistance [N/mm.sup.2] Demolding after RT after [Days] curing crosslinking Ex.22 1 8 25 CEx.10 12 — 3.2 CEx.11 2 4.5 Test specimen deformed, not testable

[0123] Post-Crosslinking Experiments:

[0124] For this purpose, the non-demolded test specimens described above of (comparative) Examples 22, 10 and 11 were stored at 120° C. for 12 h. The pressure resistance was then determined in accordance with DIN EN 12808 Part 3 using 2*2*4 cm prisms. The pressure resistance value relates to the corrected contact area. The test results are summarized in Table 7.

[0125] The test specimen from Example 22 showed a considerable post-crosslinking effect: the pressure resistance could be increased further by post-crosslinking.

[0126] No significant post-crosslinking effect could be achieved for the test specimen from Comparative example 11.

[0127] Even after post-crosslinking, the pressure resistance of the test specimen from Comparative example 10 remained dramatically below that of Example 22.

[0128] Crosslinkability of Polymer Films

[0129] The crosslinkable redispersible powders (DPP) of Example 18, Example 20 and Comparative example 8 were each redispersed in water to form a dispersion with a 50% solids content.

[0130] Then the curing agent Epilink 701 (trade name of EVONIK) was mixed according to the molar mixing ratios in Table 8.

[0131] Polymer films were produced with the dispersions thus obtained.

[0132] After drying, the polymer films were stored as indicated below, and the breaking strengths were then determined in accordance with DIN 53504 (S3a): [0133] 7d RT: 7 days storage in air at room temperature; [0134] 7d H.sub.2O+7d RT: 7 days of storage in water and then 7 days of storage in air at room temperature.

[0135] The results are summarized in table 8.

[0136] The results show that the inventive crosslinkable redispersion powders of Examples 18 and 20 can be effectively crosslinked after redispersion in water and that the epoxy resin is amenable to crosslinking with amine crosslinkers such as Epilink 701.

[0137] It follows from this that in the course of the production and storage of the crosslinkable redispersion powders according to the invention there was no premature crosslinking and the crosslinkable redispersion powders according to the invention are very readily redispersible, despite their high epoxy resin content.

TABLE-US-00008 TABLE 8 Test results with crosslinked polymer films: Redispersion Molar ratio Epoxide/ Breaking strength powders curing agent Storage [MPa] Ex.20 0 7d RT 1.69 0.8 7d RT 10.4 0.8 7d H.sub.2O + 7d RT 7.78 1.2 7d RT 14.2 1.2 7d H.sub.2O + 7d RT 15.9 Ex.18 0 7d RT 2.38 0.8 7d RT 11.8 0.8 7d H.sub.2O + 7d RT 10.4 1.2 7d RT 15.8 1.2 7d H.sub.2O + 7d RT 15 CEx.8 0 7d RT 7.1 0.8 7d RT 10.3 0.8 7d H.sub.2O + 7d RT 9.7 1.2 7d RT 9.2 1.2 7d H.sub.2O + 7d RT 5.1