CURABLE COMPOSITION FOR ALKALINE SUBSTRATES

Abstract

Methods of using a curable composition, the curable composition including at least one polyether having blocked hydroxyl groups as the plasticizer on at least one alkaline substrate. The curable composition is storage-stable, easy to handle and highly elastic after curing, and does not show any tendency to separate or migrate. It enables elastic bonding, sealing or coating of alkaline substrates, such as, in particular, fresh or green concrete or cement mortar, without occurrence of troublesome odors triggered by plasticizer hydrolysis.

Claims

1. A method comprising: contacting a curable composition comprising at least one polyether having blocked hydroxyl groups as plasticizer with a surface of at least one alkaline substrate, the surface of the alkaline substrate being configured such that when the surface is wetted with water the pH of the water-wetted alkaline substrate surface is at least 10.

2. The method as claimed in claim 1, wherein the alkaline substrate is a fresh concrete, fresh cement mortar, fresh lime mortar or a fresh lime or silicate paint.

3. The method as claimed in claim 1, wherein the blocked hydroxyl groups are selected from the group consisting of acetal, ester, aceto ester, carbonate and urethane groups.

4. The method as claimed in claim 1, wherein 70% to 100% by weight of the repeat units in the polyether consist of 1,2-propyleneoxy groups, and 0% to 30% by weight of the repeat units consist of 1,2-ethyleneoxy groups.

5. The method as claimed in claim 1, wherein the polyether having blocked hydroxyl groups has an average molecular weight M.sub.n in the range from 600 to 10,000 g/mol, determined by means of gel permeation chromatography (GPC) versus polystyrene as standard with tetrahydrofuran as mobile phase, refractive index detector and evaluation from 200 g/mol.

6. The method as claimed in claim 1, wherein the polyether having blocked hydroxyl groups is derived from at least one hydroxy-functional polyether selected from the group consisting of alcohol-started polyoxypropylene monools having an OH number in the range from 25 to 90 mg KOH/g, polyoxypropylene diols having an OH number in the range from 12 to 155 mg KOH/g, trimethylolpropane- or glycerol-started, optionally ethylene oxide-terminated polyoxypropylene triols having an average OH functionality in the range from 2.2 to 3 and an OH number in the range from 22 to 230 mg KOH/g, and sugar alcohol-started polyoxypropylene polyols having an average OH functionality in the range from 3 to 6.

7. The method as claimed in claim 1, wherein the curable composition comprises at least one polymer containing isocyanate and/or silane groups.

8. The method as claimed in claim 1, wherein the curable composition comprises at least one polymer containing isocyanate groups and at least one latent curing agent.

9. The method as claimed in claim 1, wherein the curable composition comprises at least one filler based on calcium carbonate.

10. The method as claimed in claim 1, wherein the curable composition comprises: 10% to 50% by weight of polymer containing isocyanate and/or silane groups, 20% to 60% by weight of fillers, and 10% to 40% by weight of polyether having blocked hydroxyl groups.

11. The method as claimed in claim 1, wherein the curable composition is configured as a one-component moisture-curing composition.

12. A method of bonding or sealing or coating, comprising the steps of: (i) providing a curable composition as plasticizer, the curable composition comprising at least one polyether having blocked hydroxyl groups, (ii) providing at least one alkaline substrate, the surface of the alkaline substrate being configured such that when the surface is wetted with water the pH of the water-wetted alkaline substrate surface is at least 10, (iii) contacting the curable composition with the alkaline substrate, and (iv) curing the composition to form a cured composition.

13. An article obtained from the method as claimed in claim 12.

14. The article as claimed in claim 13, wherein the article is a parquet floor that has been bonded to a screed of concrete or cement mortar.

15. An adhesive bond obtained from the method as claimed in claim 1, the adhesive bond comprising a cured form of the curable composition and at least one substrate having a surface that is adhered to the cured form of the curable composition, wherein the surface of the at least one substrate is configured such that it was alkaline at the time of contacting the curable composition, and when the surface of the at least one substrate is wetted with water the pH of the water-wetted substrate surface is at least 10.

16. An adhesive bond obtained from the method as claimed in claim 12, the adhesive bond comprising the cured composition and at least one substrate having a surface that adheres to the cured composition, wherein the surface of the at least one substrate is configured such that it was alkaline at the time of contacting the curable composition, and when the surface of the at least one substrate is wetted with water the pH of the water-wetted substrate surface is at least 10.

Description

EXAMPLES

[0229] Working examples are adduced hereinafter, which are intended to elucidate the invention described. The invention is of course not limited to these described working examples.

[0230] “Standard climatic conditions” (“SCC”) refer to a temperature of 23±1° C. and a relative air humidity of 50±5%.

[0231] Unless otherwise stated, the chemicals used were from Sigma-Aldrich Chemie GmbH.

Preparation of Polyethers Having Blocked Hydroxyl Groups:

[0232] Viscosity was measured with a thermostated Rheotec RC30 cone-plate viscometer (cone diameter 25 mm, cone angle 1°, cone tip-plate distance 0.05 mm, shear rate 10 s.sup.−1).

[0233] Infrared spectra (FT-IR) were measured as undiluted films on a Nicolet iS5 FT-IR instrument from Thermo Scientific equipped with a horizontal ATR measurement unit with a diamond crystal. The absorption bands are reported in wavenumbers (cm.sup.−1).

[0234] .sup.1H NMR spectra were measured on a spectrometer of the Bruker Ascend 400 type at 400.14 MHz; the chemical shifts δ are reported in ppm relative to tetramethylsilane (TMS). No distinction was made between true coupling and pseudo-coupling patterns.

Polyether-1: n-Butanol-Started Acetylated PPG Monool with Average Molecular Weight about 800 g/mol

[0235] 120.00 g of n-butanol-started polyoxypropylene monool (Synalox® 100-20B, average molecular weight about 750 g/mol; from DowDuPont Inc.) and 18.74 g of acetic anhydride were initially charged in a round-bottom flask with distillation attachment under a nitrogen atmosphere. Then the reaction mixture was stirred under a gentle nitrogen stream at 130° C., with collection of acetic acid as distillate. Subsequently, the volatile constituents were removed from the reaction mixture at 80° C. and a reduced pressure of 10 mbar. A clear, colorless liquid having a viscosity of 75 mPa.Math.s at 20° C. was obtained.

[0236] FT-IR: 2970, 2931, 2867, 1738, 1454, 1372, 1345, 1296, 1241, 1098, 1014, 959, 925, 866, 827.

[0237] .sup.1H NMR (CDCl.sub.3): 5.02 (hept., 1H, CH.sub.2(CH.sub.3)CH—OAc), 3.75-3.34 (2×m, about 39H, OCH.sub.2CH(CH.sub.3)O), 3.33-3.28 (m, 2H, CH.sub.3CH.sub.2CH.sub.2CH.sub.2O), 2.04 (s, 3H, O(CO)CH.sub.3), 1.55 (quint., 2H, CH.sub.3CH.sub.2CH.sub.2CH.sub.2O), 1.36 (sext., 2H, CH.sub.3CH.sub.2CH.sub.2CH.sub.2O), 1.22 (d, 3H, CH.sub.2(CH.sub.3)CH—OAc), 1.17-1.10 (m, about 36H, OCH.sub.2CH(CH.sub.3)O), 0.91 (t, 3H, CH.sub.3CH.sub.2CH.sub.2CH.sub.2O).

Polyether-2: Diacetylated PPG Diol with Average Molecular Weight about 1100 g/mol

[0238] 80.00 g of polyoxypropylene diol (Voranol® P 1010, OH number 110 mg KOH/g; from DowDuPont Inc.) and 18.74 g of acetic anhydride were converted as described for Polyether-1. A clear, colorless liquid having a viscosity of 145 mPa.Math.s at 20° C. was obtained.

Polyether-3: Diacetylated PPG Diol with Average Molecular Weight about 2100 g/mol

[0239] 160.00 g of polyoxypropylene diol (Voranol® 2000 L, OH number 56 mg KOH/g; from DowDuPont Inc.) and 18.74 g of acetic anhydride were converted as described for Polyether-1. A clear, colorless liquid having a viscosity of 400 mPa.Math.s at 20° C. was obtained.

Preparation of Further Starting Materials:

Polymer P1:

[0240] 3080 g of polyoxypropylene diol (Acclaim® 4200, from Covestro AG; OH number 28.5 mg KOH/g), 1540 g of polyoxypropylenepolyoxyethylene triol (Caradol® MD34-02, from Shell Chemicals Co.; OH number 35.0 mg KOH/g) and 385 g of tolylene diisocyanate (Desmodur® T 80 P, Covestro AG) were reacted at 80° C. by a known method to give an NCO-terminated polyurethane polymer which is liquid at room temperature and has a content of free isocyanate groups of 1.50% by weight.

Aldimine-1: N,NBis(2,2-dimethyl-3-lauroyloxypropylidene)-3-aminomethyl-3,5,5-trimethylcyclohexylamine

[0241] 598 g (2.1 mol) of 2,2-dimethyl-3-lauroyloxypropanal was initially charged in a round-bottom flask under a nitrogen atmosphere. Then 170.3 g (1 mol) of 3-aminomethyl-3,5,5-trimethylcyclohexylam ine (Vestamin® IPD, from Evonik Industries AG) was added with good stirring, and then the volatile constituents were removed at 80° C. and a reduced pressure of 10 mbar. 732 g of a colorless liquid having an amine content of 2.73 mmol N/g was obtained, corresponding to a calculated aldimine equivalent weight of 367 g/mol.

Thixotropic Agent T-1:

[0242] A vacuum mixer was initially charged with 300 g of polyether-1 and 48 g of methylene diphenyl 4,4diisocyanate (Desmodur® 44 MC L, from Covestro AG) and heated up slightly, and then 27 g of n-butylamine was slowly added dropwise with vigorous stirring. The resultant paste was stirred for a further hour under reduced pressure while cooling. A white, finely divided, homogeneous, spreadable paste was obtained.

Thixotropic Agent T-2:

[0243] Prepared as described for thixotropic agent T-1, except that 300 g of polyether-2 was used in place of polyether-1. A white, finely divided, homogeneous, spreadable paste was obtained.

Thixotropic Agent T-3:

[0244] Prepared as described for thixotropic agent T-1, except that 300 g of diisodecyl phthalate (Palatinol® 10-P, from BASF SE) was used in place of Polyether-1. A white, finely divided, homogeneous, spreadable paste was obtained.

Thixotropic Agent T-4:

[0245] Prepared as described for thixotropic agent T-1, except that 300 g of diisononyl cyclohexane-1,2-dicarboxylate (Hexamoll® DINCH, from BASF SE) was used in place of Polyether-1. A white, finely divided, homogeneous, spreadable paste was obtained.

Production of Mortar Prisms:

[0246] A dry mix was produced with 1300 parts by weight (PW) of 0 to 1 mm quartz sand, 200 PW of ground limestone (unburnt) and 900 PW of CEM I 42.5N portland cement. Separately, 400 PW of water was mixed with 6.3 PW of Sika® ViscoCrete®-3082 (retardant/plasticizer; from Sika Schweiz AG), and this mixture was mixed well with the dry mix in a mechanical mixer for 3 min. The mortar obtained was poured into several 80×40×40 mm molds, covered with plastic film and stored under standard climatic conditions.

[0247] After 24 hours, the plastic film was removed and cured but still fresh mortar prisms were taken out of the molds, brushed on the outside with a steel brush and freed of dust. Curable compositions as described below were applied immediately to the fresh (green) mortar prisms thus prepared.

Production of Curable (One-Component) Compositions:

Compositions Z1 to Z5

[0248] For each composition, the ingredients specified in table 1 were mixed in the amounts specified (in parts by weight) by means of a centrifugal mixer (SpeedMixer™ DAC 150, FlackTek Inc.) with exclusion of moisture at 3000 rpm for one minute.

[0249] Each composition was tested as follows:

[0250] As a measure of the open time, skin time (ST) was determined. For this purpose, a few grams of the composition were applied to cardboard in a layer thickness of about 2 mm and, under standard climatic conditions, the first period of time after which no residues remained any longer on an LDPE pipette used to gently tap the surface of the composition was determined.

[0251] Shore A hardness was determined to DIN 53505 on test specimens cured under standard climatic conditions for 14 days.

[0252] To determine the mechanical properties, the composition was applied to a PTFE-coated film to give a film of thickness 2 mm, the film was stored under standard climatic conditions for 14 days, and a few dumbbells having a length of 75 mm with a bar length of 30 mm and a bar width of 4 mm were punched out of the film and these were tested in accordance with DIN EN 53504 at a strain rate of 200 mm/minute for Tensile strength (breaking force), Elongation at break, Modulus of elasticity 5% (at 0.5%-5% elongation) and Modulus of elasticity 25% (at 0.5%-25% elongation).

[0253] Appearance was assessed visually on the films produced. “Nice” was used to describe a nontacky film without blisters.

[0254] Odor was assessed by smelling by nose at a distance of 2 cm from the freshly produced films. “No” means that no odor was perceptible.

[0255] The results are reported in table 1.

[0256] The compositions labeled (Ref.) do not contain any inventive polyethers having blocked hydroxyl groups.

TABLE-US-00001 TABLE 1 Composition (in parts by weight) and properties of Z1 to Z5. Z4 Z5 Composition Z1 Z2 Z3 (Ref.) (Ref.) Polymer P1 28.00 28.00 28.00 28.00 28.00 Aldimine-1 2.58 2.58 2.58 2.58 2.58 Polyether-1 14.00 — — — — Polyether-2 — 14.00 — — — Polyether-3 — — 14.00 — — DIDP .sup.1 — — — 14.00 — DINCH .sup.2 — — — — 14.00 Thixotropic agent T-1 T-2 T-1 T-3 T-4 20.00 20.00 20.00 20.00 20.00 Chalk .sup.3 33.89 33.89 33.89 33.89 33.89 Salicylic acid solution .sup.4 1.50 1.50 1.50 1.50 1.50 Dibutyltin dilaurate 0.03 0.03 0.03 0.03 0.03 ST [min] 25 25 25 25 25 Shore A 10 16 14 15 15 Tensile strength [MPa] 1.14 1.37 n.d. 1.29 1.10 Elongation at break [%] 809 784 n.d. 918 840 Modulus of elasticity 5% 0.52 0.54 n.d. 0.86 0.73 Modulus of elasticity 25% 0.26 0.45 n.d. 0.47 0.55 Appearance nice nice nice nice nice Odor no no no no no “n.d.” stands for “not determined” .sup.1 diisodecyl phthalate (Palatinol ® 10-P, from BASF SE) .sup.2 diisononyl cyclohexane-1,2-dicarboxylate (Hexamoll ® DINCH, from BASF SE) .sup.3 Omyacarb ® 5-GU (from Omya AG) .sup.4 5% by weight in di(2-ethylhexyl) adipate

Use of the Curable Compositions on Fresh Mortar:

Examples 1 to 5

[0257] Each of compositions Z1 to Z5, produced as described above, was applied to two of the fresh (green) mortar prisms prepared as described above in a layer thickness of 2 mm over an area of 30×80 mm. The first prism coated in this way was stored in a closed aluminum can in an air circulation oven at 80° C. for 24 h, and then tested for odor development. These results are labeled “(1d 80° C.)”. The second coated prism was stored in a closed aluminum can under standard climatic conditions for 7 days and then likewise tested for odor development. These results are labeled “(7d SCC)”. Odor development was determined by cautiously opening the aluminum can under standard climatic conditions and immediately detecting any odor by smelling by nose in the headspace of the aluminum can and of the composition. “No” means that no odor was perceptible. “Mild” refers to a slight odor as is typical of the composition in the warm state as intrinsic odor. “Distinct” refers to a distinctly perceptible musty odor. “Strong” refers to a strong musty odor.

[0258] The results are reported in table 2.

[0259] The examples labeled (Ref.) are comparative examples.

TABLE-US-00002 TABLE 2 Properties (odor formation) of compositions Z1 to Z5 on fresh (green) mortar. 4 5 Example 1 2 3 (Ref.) (Ref.) Composition Z1 Z2 Z3 Z4 Z5 Odor formation (7 d SCC) no no no distinct distinct (1 d 80° C.) mild mild mild strong strong