Anticorrosive composition

Abstract

An anticorrosive composition comprising (a) one or more alkali metal silicate components of the formula Me.sub.2O.Math.xSiO.sub.2, wherein x has a value of from 0.5 to 4.0, (b) one or more alkali metal phosphate components of the formula Me.sub.2O:nP.sub.2O.sub.5, wherein n has a value of from 0.33 to 1 and/or hydrates thereof, (c) one or more carboxylic acids having 6-22 carbon atoms and/or salts thereof: and the use of the composition for imparting anticorrosive properties to a material such as a mineral wool product.

Claims

1. A method of imparting anticorrosive properties to a product selected from mineral wool products and aerogel products, wherein the method comprises contacting at least a surface layer of the product with an anticorrosive composition, wherein the composition comprises: 100-500 g/L Na.sub.2SiO.sub.3, 2-50 g/L sebacic acid, 20-80 g/L Na.sub.3PO.sub.4, 0.1-100 g/L of at least one surface-active compound.

2. The method of claim 1, wherein the at least one surface-active compound is selected from soaps and surfactants.

3. The method of claim 1, wherein the at least one surface-active compound is selected from alkali stable water dispersible surfactants, alkali stable water soluble surfactants, and emulsifying surfactants.

4. The method of claim 1, wherein the composition further comprises a hydrophobic agent comprising at least one silicone compound.

5. The method of claim 1, wherein the composition further comprises one or more water-miscible organic solvents.

6. The method of claim 1, wherein the composition is dispersed in a mineral wool product.

7. The method of claim 1, wherein the product is selected from a pipe section, a roof product, a facade product, a mat, and a wired mat.

8. The method of claim 1, wherein the product is selected from mineral wool products.

9. An anticorrosive composition, wherein the composition comprises: 100-500 g/L Na.sub.2SiO.sub.3, 2-50 g/L sebacic acid, 20-80 g/L Na.sub.3PO.sub.4, 0.1-100 g/L of at least one surface-active compound, and wherein the composition is present on and/or in a mineral wool product or an aerogel product.

10. The composition of claim 9, wherein the mineral wool product or aerogel product is selected from a pipe section, a roof product, a facade product, a mat, and a wired mat.

11. The composition of claim 9, wherein the mineral wool product or aerogel product is a pipe section or a mat.

12. The composition of claim 11, wherein the composition is present in a surface layer of the pipe section or mat.

13. The composition of claim 9, wherein the at least one surface-active compound comprises at least one of a soap and a surfactant.

14. The composition of claim 9, wherein the composition further comprises a hydrophobic agent comprising at least one silicone compound.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention will be described in more detail and by way of example on the basis of the drawings in which

(2) FIG. 1 is a schematic illustration of the setup of the tests described below;

(3) FIG. 2 shows a real setup of the testing equipment;

(4) FIG. 3 is a graphical representation of the cycling test set forth below;

(5) FIG. 4 shows the top side of steel coupons previously covered by Prorox PS960 (see below) treated with corrosion inhibitor after 21 cycles (no removal of deposits);

(6) FIG. 5 shows the bottom side of steel coupons previously covered by Prorox PS960 treated with corrosion inhibitor after 21 cycles (no removal of deposits);

(7) FIG. 6 shows a close-up of the coupons shown in FIG. 5

(8) FIG. 7 shows a close-up of a test coupon (A-21-6 as identified below) shown in FIGS. 5 and 6 after cleaning;

(9) FIG. 8 shows the top side of steel coupons previously covered by Prorox PS960 not treated with corrosion inhibitor after 21 cycles (no removal of deposits);

(10) FIG. 9 shows the bottom side of steel coupons previously covered by Prorox PS960 not treated with corrosion inhibitor after 21 cycles (no removal of deposits);

(11) FIG. 10 shows the side of steel coupons previously covered by Prorox PS960 not treated with corrosion inhibitor after 21 cycles (no removal of deposits);

(12) FIG. 11 shows a close-up of FIG. 10;

(13) FIG. 12 shows a close-up of a test coupon (B-21-6 as identified below) shown in FIGS. 8 to 11 after cleaning;

(14) FIG. 13 shows the top side of steel coupons previously covered by Prorox PS960 WR-Tech treated with corrosion inhibitor after 21 cycles (no removal of deposits; see Test A below);

(15) FIG. 14 shows the bottom side of steel coupons previously covered by Prorox PS960 WR-Tech treated with corrosion inhibitor after 21 cycles (no removal of deposits; see Test A below);

(16) FIG. 15 shows a close-up of a test coupon (A-22-4 as identified below) as shown in FIGS. 13 and 14 after cleaning;

(17) FIG. 16 shows a close-up of a test coupon (A-22-6 as identified below) as shown in FIGS. 13 and 14 after cleaning;

(18) FIG. 17 shows the top side of steel coupons previously covered by Prorox PS960 WR-Tech treated with corrosion inhibitor after 21 cycles (no removal of deposits; see Test B below);

(19) FIG. 18 shows the bottom side of steel coupons previously covered by Prorox PS960 WR-Tech treated with corrosion inhibitor after 21 cycles (no removal of deposits; see Test B below);

(20) FIG. 19 shows a close-up of a test coupon (B-22-2 as identified below) as shown in FIGS. 17 and 18 after cleaning; and

(21) FIG. 20 shows a close-up of a test coupon (B-22-3 as identified below) as shown in FIGS. 17 and 18 after cleaning.

(22) The present invention is further illustrated by the following examples:

(23) In order to test the performance of the anticorrosive composition according to the present invention, the CUI performance of stone wool pipe sections of the commercially available product ProRox PS 960 with an anticorrosive composition according to the present invention has been compared with the anticorrosive performance of a standard stone wool pipe section of ProRox PS 960 without the anticorrosive composition according to the present invention.

(24) Test Setup and Test Conditions

(25) The test setup in general follows ASTM G189-07, but with the following modifications: PTFE spacers between samples have been replaced by special silicone O-rings Clamping of the test equipment and coupons is achieved using a spring compression system to counter for thermal expansion of the system Ring formed test coupons are 14.3 mm wide compared to the width in ASTM G189-07 of 6.35 mm

(26) None of the modifications can be considered a relaxation compared to the test method and apparatus described in ASTM G189-07.

(27) Equipment

(28) The following simulation equipment is used: a) Ring shaped test coupons made from carbon steel pipe, ASTM A106 Grade B, with a width of 14.3 mm and diameter of 60 mm, polished to a 600 grit finish. b) O-rings for sealing and separation. c) Pipe insulation, 160 ex., 60 inside with and without corrosion inhibitor. d) Aluminium pipe jackets. e) Specially designed test rig consisting of two end pieces, between which test rings are mounted. f) Threaded rods mounted with coil springs to tighten the arrangement. The coil springs ensure that thermal extensions can be absorbed. g) Julabo Corio (laboratory circulator) heating/cooling bath with circulation as well as pipe and hose connections. The bath is programmable according to the time/temperature control. h) Liquid circulating non-corrosive heating medium that can run at 60 and 150 C. Thermocouples measuring the temperature on the pipe surface under the insulation. i) Control computer. j) Data logger for logging temperature during test. k) Test liquid delivery system/metering pumps with controllers. l) Silicone sealant. m) Insulation for heating pipes between heaters and installation.

(29) A schematic of the test setup can be seen in FIG. 1 and a picture of the test setup can be seen in FIG. 2.

(30) Test Conditions

(31) Two separate tests were conducted. The Conditions during the test were as follows:

(32) Test 1:

(33) (a) Cyclic testing with the following temperature conditions, see also FIG. 3 for graphical representation of the test cycle. Total water injection per test cycle is 85 mL and total injection of 1785 mL for the entire test is 21 days.

(34) TABLE-US-00001 Ramp Ramp Step Wet up Dry down Temperature [ C.] 60 60 to 150 150 150 to 60 Duration [hr] 18 1 4 1 Water injection 40 ml/10 min. + no no no 2.5 ml/hr b) Test duration 21 cycles (21 days) c) Test solution is deionized water d) Test solution enters through the top of the insulation via two feed tubes placed 42.9 mm apart, see FIGS. 1 and 2 e) The insulation is drained via a centred hole in the bottom of the insulation, see FIG. 1 f) 6 identical ring formed test coupons made from carbon steel pipe, ASTM A106 Grade B, with a width of 14.3 mm and diameter of 60 mm, polished to a 600 grit finish g) The insulation material is sealed to the test pipe using silicone, creating a 25 cm long annulus. The insulation is secured tightly to the pipe surface using stainless steel wire. The outer aluminium jacket is secured around the insulation using hose clamps and sealed longitudinally and to the flange ends using silicone.
Test 2:

(35) Test conditions identical to Test 1, but with a higher volume of water injected per test cycle. Total water injection per test cycle is 119 mL and total injection of 2499 mL for the entire test is 21 days.

(36) TABLE-US-00002 Ramp Ramp Step Wet up Dry down Temperature [ C.] 60 60 to 150 150 150 to 60 Duration [hr] 18 1 4 1 Water injection 42.5 ml (injected no no no over a period of 10 min.) + 4.25 ml/hr
Anticorrosive Composition Tested

(37) Two different concentrations of the anticorrosive composition were used in the two tests and were applied to the stone wool insulation with different techniques, resulting in the same concentration of anticorrosive composition per cubic centimeter of treated pipe insulation.

(38) Test 1:

(39) To apply the anticorrosive composition to a 500 mm long pipe insulation, with inner diameter of 60 mm, a total of 0.85 liters of the anticorrosive composition mixture is needed, in order to treat the inner layer of the pipe insulation with a depth of 10 mm. The anticorrosive composition according to the present invention tested was as follows:

(40) 33.75 g/L Na.sub.2SiO.sub.3+2.25 g/L sebacic acid+6.75 g/L Na.sub.3PO.sub.4+250 mL/L isopropyl alcohol and 750 mL/L demineralized water

(41) The corrosion inhibitor has been applied to the test specimen by mixing in a plastic container of 1 L size 0.75 litres of demineralized water and then mix in the following chemicals in the order listed below: 1. 33.75 g of sodium silicate Na.sub.2SiO.sub.3 and let dissolve under stirring/shaking 2. 2.25 g of sebacic acid, and let dissolve under stirring or shaking 3. 6.75 g trisodium phosphate Na.sub.3PO.sub.4 and let dissolve

(42) In the end 0.25 L IPA (isopropyl alcohol) is to be used with each 0.75 L mixture.

(43) The solution is then sprayed on the inner side of the pipe insulation, first the IPA and then the anticorrosive mixture to ensure that at the inner layer of the insulation product is fully impregnated with a depth of around 10 mm, and then dry it.

(44) The insulation sample, now treated with the anticorrosive composition is then tested for CUI performance as per above described test 1.

(45) Test 2:

(46) To apply the anticorrosive composition to a 500 mm long pipe insulation, with inner diameter of 60 mm, a total of 0.13 L of the anticorrosive composition mixture is needed, in order to treat the inner layer of the pipe insulation with a depth of 10 mm. The anticorrosive composition according to the present invention tested was as follows: 220 g/L Na.sub.2SiO.sub.3+14.67 g/L sebacic acid+44 g/L Na.sub.3PO.sub.4+10 g/L emulsifying co-surfactant+4 g/L alkali stable surfactant

(47) All chemicals dissolved in demineralized water in the above order balanced to 1 L.

(48) The solution is then sprayed on the inner side of the pipe insulation and the inner layer of the insulation product is fully impregnated with a depth of around 10 mm and then dried.

(49) The insulation sample now treated with the anticorrosive composition is then tested for CUI performance as per above described test 2.

Results

(50) Upon conclusion of the 21 test cycles, specimens have been washed with DI water and a nylon brush, rinsed with ethanol and dried to remove loose corrosion products and insulation from the surface, before the first weighing. Following this, corrosion products have been removed from the test specimens by immersion in inhibited 16 wt % hydrochloric as per DS/EN ISO 8407. Following rinsing the test specimens were weighed again.

(51) After removal of corrosion products, the extent of localised corrosion was estimated (if relevant), as well as measurement of pitting depth (if relevant).

(52) The results are summarized in Table 1 (Test 1 with ProRox PS 960 treated with corrosion inhibitor), Table 2 (Test 1 with ProRox PS 960) and table 3 (Test 2 with ProRox PS 960 treated with corrosion inhibitor, and higher water injection during test)

(53) Photographs from Test 1 of test coupons tested with ProRox PS 960 treated with corrosion inhibitor prior to and after removal of deposits and corrosion products can be seen in FIGS. 4 to 7.

(54) Photographs from Test 1 of test coupons tested with ProRox PS 960 prior to and after removal of deposits and corrosion products can be seen in FIGS. 8 to 12.

(55) Photographs from Test 2 of test coupons tested with ProRox PS 960 WR-Tech treated with corrosion inhibitor prior to and after removal of deposits and corrosion products can be seen in FIGS. 13 to 20.

(56) Test 1 ProRox PS 960 treated with corrosion inhibitor

(57) Regarding the results from testing with PS 960 treated with corrosion inhibitor, there is an error in the weight result from test coupon A-21-1, as some of the original mill scale from the unexposed side of the coupon was removed during cleaning, thus resulting in an erroneous weight loss result. The coupon was upon inspection free from corrosion, and only one very shallow small pit-like attack was observed using 10 magnification.

(58) On test coupon A21-6 one small diameter pit was detected.

(59) Due to the very few, small and shallow localised attacks observed on the tested coupons and the inherent uncertainties and measurement error associated with determining the area of affected surface, calculation of localised corrosion rate has not been performed as this would give misleading results.

(60) During the 21 cycles of testing water draining from the test was measured to be slightly alkaline (app. pH 8-10).

(61) TABLE-US-00003 TABLE 1 ProRox PS 960 with corrosion inhibitor, measurement data from test coupons Weight, Max. after Weight, Estimated local Max. test, with after Weight affected Uniform corrosion Meassured Weight, corrosion test, Weight difference Exposure Surface surface corrosions rate, pitting Specimen Specimen start products cleaned difference corrected time area area rate estimated depth position no. [g] [g] [g] [g] [g] [days] [cm2] (%) [m/year] [m/year] [m] 1 A-21-1 97.5218 97.5220 97.5041 0.0177 0.0129 21 26.85 na 10.61 na 10 2 A-21-2 97.4840 97.4861 97.4757 0.0083 0.0035 21 26.85 na 2.86 na na 3 A-21-3 97.0120 97.0157 97.0055 0.0065 0.0017 21 26.85 na 1.37 na na 4 A-21-4 97.6135 97.6137 97.6065 0.007 0.0022 21 26.85 na 1.79 na na 5 A-21-5 97.6579 97.6585 97.6474 0.0105 0.0057 21 26.85 na 4.67 na 50 6 A-21-6 97.1038 97.1059 97.0983 0.0055 0.0007 21 26.85 na 0.55 na <10
Prorox PS960 ProRox PS 960

(62) The corrosion attacks observed on the test coupons as result of the test although localised in nature due to the wetting properties of the insulation material and the metal surface do not give rise to pronounced pitting corrosion, instead the corrosion is observed to be general in appearance upon removal of the corrosion products, see FIG. 12.

(63) During the 21 cycles of testing, water draining from the test were measured to go from slightly alkaline (app. pH 8) to slightly acidic (app. pH 6).

(64) TABLE-US-00004 TABLE 2 ProRox PS 960, measurement data from test coupons Weight, Max. after Weight, Estimated local Max. test, with after Weight affected Uniform corrosion Measured Weight, corrosion test, Weight difference Exposure Surface surface corrosions rate, pitting Specimen Specimen start products cleaned difference corrected time area area rate estimated depth position no. [g] [g] [g] [g] [g] [days] [cm2] (%) [m/year] [m/year] [m] 1 B-21-1 97.2259 97.2035 97.1884 0.0375 0.0327 21 26.85 45 26.93 59.85 60 2 B-21-2 96.8226 96.8069 96.7936 0.029 0.0242 21 26.85 30 19.93 66.42 30 3 B-21-3 97.2541 97.2319 97.2157 0.0384 0.0336 21 26.85 40 27.68 69.19 60 4 B-21-4 97.6102 97.5888 97.5683 0.0419 0.0371 21 26.85 55 30.56 55.57 60 5 B-21-5 97.0744 97.0368 97.0160 0.0584 0.0536 21 26.85 65 44.17 67.95 30 6 B-21-6 97.2803 97.2492 97.2130 0.0673 0.0625 21 26.85 70 51.51 73.58 50
Test 2 PS960 ProRox PS 960 Treated with Corrosion Inhibitor

(65) The tests were conducted in duplicate with a 40% higher water injection volume than in Test 1.

(66) The coupons were upon inspection free from corrosion and only small areas with shallow localised corrosion was observed upon inspection under 10-50 magnification. The total area of these the localised corrosion attacks was less than 0.5% of total exposed sample area.

(67) Due to the very few, small and shallow localised attacks observed on the tested coupons and the inherent uncertainties and measurement error associated with determining the area of affected surface, calculation of localised corrosion rate in table 3 has not been performed as this would give misleading results. The calculated average annual uniform corrosion rate, based on all twelve test coupons and on the 21 test cycles, is 2.22 m/year.

(68) During the 21 cycles of testing water draining from the test A&B were measured to be slightly alkaline (app. pH 8-10).

(69) TABLE-US-00005 TABLE 3 ProRox PS 960 WR-Tech with corrosion inhibitor, measurement data from test coupons Weight, Max. after Weight, Estimated local Spec- test, with after Weight affected Uniform corrosion imen Spec- Weight, corrosion test, Cleaning Weight difference Exposure Surface surface corrosions rate, posi- imen start products cleaned time difference corrected time area density area rate estimated tion no. [g] [g] [g] (min) [g] [g] [days] [cm2] [g/cm3] (%) [m/year] [m/year] 1 A-22-1 84.7434 84.7791 84.7391 30 0.0043 0.0014 21 26.75 7.85 na 1.12 na 2 A-22-2 87.9846 88.1281 87.9782 30 0.0064 0.0035 21 26.75 7.85 na 2.86 na 3 A-22-3 85.2461 85.3503 85.2395 30 0.0066 0.0051 21 26.75 7.85 na 4.25 na 4 A-22-4 85.6372 85.6660 85.6339 20 0.0033 0.0023 21 26.75 7.85 na 1.92 na 5 A-22-5 88.7391 88.7749 88.7342 20 0.0049 0.0039 21 26.75 7.85 na 3.24 na 6 A-22-6 88.6460 88.6730 88.6420 20 0.004 0.0030 21 26.75 7.85 na 2.50 na 1 B-22-1 86.0922 86.1644 86.0887 20 0.0035 0.0025 21 26.75 7.85 na 2.09 na 2 B-22-2 84.0520 84.0897 84.0490 20 0.003 0.0020 21 26.75 7.85 na 1.67 na 3 B-22-3 84.2084 84.2998 84.2042 20 0.0042 0.0032 21 26.75 7.85 na 2.67 na 4 B-22-4 88.1556 88.2877 88.1524 20 0.0032 0.0022 21 26.75 7.85 na 1.84 na 5 B-22-5 89.1120 89.1383 89.1100 20 0.002 0.0010 21 26.75 7.85 na 0.84 na 6 B-22-6 85.5794 85.5911 85.5764 20 0.003 0.0020 21 26.75 7.85 na 1.67 na

CONCLUSION

(70) The modified ASTM G189-7 test schedule was carried out successfully testing stone wool insulation material with and without treatment with corrosion inhibiting compounds using no spacers to the pipe substrate. The stone wool insulation material impregnated with corrosion inhibiting compounds results in a markedly lower corrosion rate on the pipe specimens compared to tests performed with the standard stone wool pipe insulation material. The calculated annual uniform corrosion rate, based on the 21 test cycles, is in average approximately fourteen times lower on the test substrates using the anticorrosive insulation material.