Corrosion-inhibiting, radically cureable composition

Abstract

A composition for sealing joints, penetrations and other leaks in particular in the construction field, including at least one ethylenically unsaturated, radically polymerizable water-soluble compound, at least one radical initiator, water and at least one corrosion inhibitor including at least one phosphate. The corresponding composition has a corrosion-inhibiting effect with respect to metal.

Claims

1. A composition for sealing joints and penetrations, comprising: a) at least one ethylenically unsaturated, free-radically polymerizable water-soluble compound, b) at least one free-radical initiator, c) water, and d) at least one corrosion inhibitor comprising at least one phosphate, wherein: the at least one ethylenically unsaturated, free-radically polymerizable water-soluble compound has a proportion by weight of 25 to 55 percent by weight, based on the total weight of the composition, the at least one phosphate comprises an alkali metal or alkaline earth metal salt of orthophosphoric acid, or a mixture thereof, and a weight ratio of the at least one ethylenically unsaturated, free-radically polymerizable water-soluble compound to water is in a range of from 0.1:1 to 3:1.

2. The composition as claimed in claim 1, wherein the at least one ethylenically unsaturated, free-radically polymerizable water-soluble compound includes at least one water-soluble (meth)acrylic compound.

3. The composition as claimed in claim 1, wherein the at least one phosphate comprises potassium dihydrogenphosphate (KH.sub.2PO.sub.4), dipotassium hydrogenphosphate (K.sub.2HPO.sub.4), potassium phosphate (K.sub.3PO.sub.4), or a mixture thereof.

4. The composition as claimed in claim 1, wherein the at least one phosphate has a proportion by weight of 0.50-10.00 percent by weight, based on the total weight of the composition.

5. The composition as claimed in claim 1, wherein the composition additionally includes at least one amine.

6. The composition as claimed in claim 5, wherein: the at least one phosphate has a proportion by weight of 0.10-5.00 percent by weight, based on the total weight of the composition, and the at least one amine has a proportion by weight of 1.00-10.00 percent by weight, based on the total weight of the composition.

7. The composition as claimed in claim 5, wherein the composition additionally comprises at least one accelerator for free-radical formation, and the accelerator comprises an ascorbic acid, a transition metal salt, a transition metal complex or a further amine other than the at least one amine.

8. The composition as claimed in claim 1, wherein the composition additionally comprises at least one accelerator for free-radical formation, and the accelerator comprises an ascorbic acid, a transition metal salt, a transition metal complex or an amine.

9. The composition as claimed in claim 1, wherein the pH of the composition is in the range from 7.0 to 13.0.

10. The composition according to claim 1, wherein: the composition is a two-component or multicomponent composition, and the amount of water in one or more components of the two-component or multicomponent composition is not more than 20.0% of a total amount of water in the two-component or multicomponent composition.

11. The composition as claimed in claim 1, wherein the at least one ethylenically unsaturated, free-radically polymerizable water-soluble compound includes a hydroxy (meth)acrylate selected from the group consisting of hydroxyethyl acrylate (HEA), hydroxyethyl methacrylate (HEMA), hydroxypropyl acrylate (HPA), hydroxypropyl methacrylate (HPMA), hydroxybutyl acrylate (HBA) and hydroxybutyl methacrylate (HBMA), or a mixture thereof.

12. A process for producing the composition as claimed in claim 1, comprising: i) providing a precursor comprising: a) the at least one ethylenically unsaturated, free-radically polymerizable water-soluble compound, b) the at least one free-radical initiator, c) water in a proportion less than 1.0 percent by weight, based on the total weight of the precursor, and d) the corrosion inhibitor, the precursor being a two-component or multicomponent composition, and ii) mixing the precursor with such an amount of water that the weight ratio of the at least one ethylenically unsaturated, free-radically polymerizable water-soluble compound to water is in the range from 0.1:1 to 3:1.

13. An injection medium for sealing joints and penetrations, comprising the composition as claimed in claim 1, wherein the composition is injected into a cavity.

14. A hydrogel obtained by polymerizing a composition comprising: a) at least one ethylenically unsaturated, free-radically polymerizable water-soluble compound, b) at least one free-radical initiator, c) water, and d) at least one corrosion inhibitor comprising at least one phosphate, wherein: the at least one ethylenically unsaturated, free-radically polymerizable water-soluble compound has a proportion by weight of 25 to 55 percent by weight, based on the total weight of the composition, the at least one phosphate comprises an alkali metal or alkaline earth metal salt of orthophosphoric acid, or a mixture thereof, and a weight ratio of the at least one ethylenically unsaturated, free-radically polymerizable water-soluble compound to water is in a range of from 0.1:1 to 3:1.

15. A method of sealing joints and penetrations, comprising: i) making up the composition as claimed in claim 1, and ii) applying the composition to a site to be sealed, where the composition polymerizes and forms a hydrogel.

16. A method of creating a steel-passivating layer in a cavity of a previously damaged reinforced concrete structure, comprising: i) making up the composition as claimed in claim 1, and ii) introducing the composition into a cavity of the reinforced concrete structure, in which the composition polymerizes and forms a steel-passivating layer in the form of a hydrogel.

Description

EXAMPLES

(1) Adduced hereinafter are working examples which are intended to elucidate the invention described in detail. It will be appreciated that the invention is not restricted to these described working examples.

(2) The following materials were used in the experiments:

(3) TABLE-US-00001 TABLE 1 HEMA hydroxyethyl methacrylate (HEMA) comprising 400 ppm of hydroquinone monomethyl ether (HMME) as polymerization inhibitor Na-AMPS sodium salt of AMPS (2-acrylamido-2- AMPS 2405 methylpropanesulfonic acid), 50% solution Monomer, in water Lubrizol TEA triethanolamine (technical grade quality, Triethanolamin 85, 85% TEA/15% diethanolamine) Ineos Oxide NAPS sodium persulfate (diluted with water to a CAS # 7775-27-1 10 wt % solution) KOH potassium hydroxide CAS # 1310-58-3 Ethanolamine CAS # 141-43-5 2-Amino-2-methyl-1-propanol CAS # 124-68-5 MDiPA N-methyldiisopropanolamine CAS # 4402-30-6 Dipotassium CAS # 7758-11-4 hydrogenphosphate Tripotassium CAS # 7778-53-2 phosphate Potassium CAS # 7778-77-0 dihydrogenphosphate
Determination of the Relevant Properties

(4) The corrosion properties of the test compositions were tested in a measurement arrangement according to European Standard EN 480-14.

(5) For the corrosion experiments, three test specimens were produced from each composition tested. In the production of the test specimens, Teflon molds with steel electrodes inserted therein were filled with the test compositions. After the test compositions had polymerized to completion, the resulting hydrogels with the steel electrode embedded in each case were removed from the molds.

(6) In the subsequent corrosion test, a constant voltage, relative to a reference electrode, was applied to the steel electrode of the test specimen. The voltage chosen corresponds to the potential difference that can be observed for steel in concrete.

(7) All the harmful effects that emanate from the composition are immediately apparent since the induced current flow does not stop owing to lack of passivation, which leads to increasing anodic dissolution of the steel electrode.

(8) The electrolyte used in the test cell was a saturated calcium hydroxide solution at a temperature of 20 C.

(9) The result of the corrosion test is either passed or failed.

(10) The viscosity of the composition was determined at 23 C. prior to the polymerization reaction with a Physica MCR101 viscometer to ISO 3219 with a coaxial cylinder measurement system at a cone angle of 120.

(11) The gelation time (gel time) at 23 C. was determined by visual testing with a 40 g batch of the composition tested in a beaker of diameter 4.5 cm. Gel time corresponds to the time before which the first gel structures are visually apparent in the reaction solution.

(12) For the swelling in water (swelling), samples having dimensions of 2.51.251.25 cm were cut out of the test specimens produced as described above and placed into demineralized water at 23 C. such that free swelling in the test medium is possible. The change in weight of the test specimens introduced was determined by gravimetric means after storage in water for 3 d and 7 d. The curing time before storage in water was 24 h.

Example 1

(13) The inventive compositions EX1 to EX6 were produced by mixing the constituents as listed in table 2. The gel time of the compositions obtained was in the range from 3 to 6 minutes, and the compositions comprising 2.0 percent by weight or more of phosphate passed the DIN EN 480-14 corrosion test.

(14) TABLE-US-00002 TABLE 2 Experiment EX 1 EX 2 EX 3 EX4 EX 5 EX 6 Constituent, percent by weight HEMA 50 50 50 50 50 50 Water 36 37 35 37 35 37 TEA (50% in water) 9 9 9 9 9 9 NAPS (10% in water) 3 3 3 3 3 3 Dipotassium 2 1 hydrogenphosphate Tripotassium phosphate 3 1 Potassium 3 1 dihydrogenphosphate Total, % by wt. 100 100 100 100 100 100 Results Gel time (min) 3 3 3 3.5 6 4 pH (average) 10.1 10 11.7 10.9 8.0f/ 8.7fresh 8.0a1h Swelling 3 d, [%] 114 80 23 28 129 122 Swell rate 7 d, [%] 150 97 9 22 140 131 DIN EN 480-14 passed yes no yes no yes no Viscosity at 5.0 n.m. 6.0 n.m. 5.0 n.m. 23 C., mPa .Math. s n.m., not measured

Example 2

(15) The inventive compositions EX7 to EX11 were produced by mixing the constituents as listed in table 3. The gel time of the compositions obtained was in the range from 3 to 6 minutes, and the compositions comprising 1.0 percent by weight or more of phosphate together with alkanolamines passed the DIN EN 480-14 corrosion test. The viscosities of the compositions were in the region of 5.0 mPa.Math.s.

(16) TABLE-US-00003 TABLE 3 Experiment EX 7 EX 8 EX 9 EX 10 EX 11 Constituent, % by wt. HEMA 50 50 50 50 50 Water 34.5 34 32.5 32 31 TEA (50% in water) 9 9 9 9 9 NAPS (10% in water) 3 3 3 3 3 Ethanolamine 3 3 5 5 MDiPA 6 Tripotassium phosphate 4 Potassium 0.5 1 0.5 1 1 dihydrogenphosphate Total, % by wt. 100 100 100 100 104 Results Gel time (min) 6 5 4 4 3 pH (average) 10.4 10.4 10.8 10.8 9.2 Swelling 3 d, [%] 109 163 25 117 193 Swell rate 7 d, [%] 113 206 4 194 228 Gel consistency very moder- moder- moder- very soft ate ate ate soft DIN EN 480-14 passed no yes yes yes yes Viscosity at 23 C., mPa .Math. s n.m. 5.0 5.0 5.0 6.0 n.m., not measured

Comparative Examples

(17) Compositions EX12 to EX16 were produced by mixing the constituents as listed in table 4. The gel time of the compositions obtained was in the range from 3 to 5 minutes. None of these compositions contains a phosphate-based corrosion inhibitor and none of the compositions passed the DIN EN 480-14 corrosion test.

(18) TABLE-US-00004 TABLE 4 Experiment EX 12 EX 13 EX 14 EX 15 EX 16 Constituent, % by wt. HEMA 50 50 50 50 50 Water 36 37 36 35 34 TEA (50% in water) 9 9 7 7 7 NAPS (10% in water) 3 3 3 3 3 Ethanolamine 2 1 4 5 6 Total, % by wt. 100 100 100 100 100 Results Gel time (min) 3 3.5 5 4.5 5 pH (average) 10.7 10.5 Swelling 3 d, [%] 19 23 15 16 17 Swell rate 7 d, [%] 0 15 17 17 17 DIN EN 480-14 passed no no no no no