ANTICORROSIVE COMPOSITION

Abstract

The present invention relates to an anticorrosive composition and the use of such a composition for imparting anticorrosive properties to a material, and a material comprising such a composition.

Claims

1.-13. (canceled)

14. An anticorrosive composition, wherein the composition comprises: (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.

15. The composition of claim 14, wherein in at least one of the one or more alkali metal silicate components x is from 0.5 to 3.0.

16. The composition of claim 14, wherein at least one of the one or more carboxylic acids has 7-14 carbon atoms.

17. The composition of claim 14, wherein at least one of the one or more alkali metal silicate components is Na.sub.2SiO.sub.3.

18. The composition of claim 14, wherein at least one of the one or more alkali metal phosphate components is a sodium phosphate.

19. The composition of claim 14, wherein at least one of the one or more alkali metal phosphate components is Na.sub.3PO.sub.4.

20. The composition of claim 14, wherein at least one of the one or more carboxylic acids is of formula HO.sub.2C(CH.sub.2).sub.nCO.sub.2H.

21. The composition of claim 20, wherein n in the formula is 2-20.

22. The composition of claim 20, wherein n in the formula is 4-10.

23. The composition of claim 20, wherein n in the formula is 8.

24. The composition of claim 14, wherein the composition comprises 60-96 weight parts (a), 1-25 weight parts (b), and 1-20 weight parts (c), based on a total weight of (a), (b) and (c).

25. The composition of claim 14, wherein the composition comprises 70-93 weight parts (a), 2-20 weight parts (b), and 2-15 weight parts (c).

26. The composition of claim 14, wherein the composition further comprises at least one surface-active compound selected from soaps and surfactants.

27. The composition of claim 14, wherein the composition further comprises at least one surface-active compound selected from alkali stable water dispersible surfactants, alkali stable water soluble surfactants, and emulsifying surfactants.

28. The composition of claim 14, 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 surface-active compound.

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

30. The composition of claim 14, wherein the composition further comprises one or more water-miscible organic solvents.

31. A method of imparting anticorrosive properties to a product selected from mineral wool products and aerogel products, wherein the method comprises contacting the product with the composition of claim 14.

32. The method of claim 31, wherein the composition is dispersed in a mineral wool product.

33. The method of claim 31, wherein the product is selected from a pipe section, a roof product, a facade product, a mat, a wired mat.

Description

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] The present invention is directed to an anticorrosive composition comprising one or more alkali metal silicate components of the formula Me.sub.2O xSiO.sub.2, wherein x is 0.5 to 3.0, one or more alkali metal phosphate components of the formula Me.sub.2O: nP.sub.2O.sub.5, wherein n is 0.33 to 1, or hydrates thereof, one or more carboxylic acids with 6-22, such 7-14 carbon atoms, or salts thereof.

[0018] In one embodiment, the anticorrosive composition according to the present invention is in form of a mixture of solids.

[0019] In one embodiment, the anticorrosive composition according to the present invention is in form of an aqueous solution/dispersion.

Alkali Metal Silicate Component

[0020] The present inventors have found that alkali metal silicate components of the formula Me.sub.2O.Math.xSiO.sub.2, wherein x is 0.5 to 4.0, such as wherein x is 0.5 to 3.0, can be used in a very effective anticorrosive composition. These components are inexpensive, easy to handle and harmless for humans and the environment.

[0021] In one embodiment, the alkali metal silicate component is a sodium silicate of the formula Na.sub.2O.Math.xSiO.sub.2x, with x=1 or 2, such as Na.sub.2SiO.sub.3.

[0022] In one embodiment, the alkali metal silicate component is Na.sub.4O.sub.4Si (sodium orthosilicate), corresponding to Me.sub.2O.Math.xSiO.sub.2, wherein x is 0.5.

[0023] It is pointed out that the alkali metal silicate component, such as sodium silicate of the formula Na.sub.2O.Math.xSiO.sub.2x, with x=1 or 2, such as Na.sub.2SiO.sub.3 can hold crystal water.

Alkali Metal Phosphate Component

[0024] The present inventors have surprisingly found that alkali metal phosphates of the formula Me.sub.2O: nP.sub.2O.sub.5, wherein n is 0.33 to 1, or hydrates thereof, can be used in a highly effective anticorrosion composition. These alkali metal phosphate components are inexpensive, easy to handle and completely harmless for humans and the environment.

[0025] In one embodiment, the alkali metal phosphate component is a sodium phosphate such as Na.sub.3PO.sub.4.

Carboxylic Acid Component

[0026] The present inventors have surprisingly found that carboxylic acids with 6-22, such 7-14 carbon atoms, or salts thereof, can be used in a highly effective anticorrosion composition. These carboxylic acid components are inexpensive, easy to handle and completely harmless for humans and the environment.

[0027] In one embodiment, the carboxylic acid component is a dicarboxylic acid component of the formula HO.sub.2C(CH.sub.2).sub.nCO.sub.2H, whereby preferably n is 2-20, in particular 4-10, such as n=8.

[0028] In one embodiment, the carboxylic acid component is in form of a soap, such as e.g. sodium stearate.

Weight Proportion of the Components

[0029] In principle, the components of the anticorrosive composition of the present invention can be used in any weight proportions.

[0030] In one embodiment, the weight proportion of the alkali metal silicate component, alkali metal phosphate component, and carboxylic acid component is 60-96 weight parts, such as 70-93 weight parts, such as 75-90 weight parts alkali metal silicate component, 1-25 weight parts, such as 2-20 weight parts, such as 3-15 weight parts alkali metal phosphate component, and 1-20 weight parts, such as 2-15 weight parts, such as 5-12 weight parts carboxylic acid component, based on the total weight of alkali metal silicate component, alkali metal phosphate component and carboxylic acid component.

[0031] In one embodiment, the composition is an aqueous solution/dispersion and comprises 4-30 gram/litre, such as 6-20 gram/litre, such as 8-14 gram/litre alkali metal silicate component, 0.1-5 gram/litre, such as 1-3.5 gram/litre, such as 2-2 gram/litre alkali metal phosphate component, and 0.1-10 gram/litre, such as 0.2-5 gram/litre, such as 0.3-1.5 gram/litre carboxylic acid component, based on the total volume of the aqueous solution/dispersion.

In Another Embodiment, the Composition is an Aqueous Solution/Dispersion and Comprises 100-500 g/l such as 150-300 g/l Na.sub.2SiO.sub.3; 2-50 g/l such as 10-20 g/l sebacic acid; 20-80 g/l such as 30-60 g/l Na.sub.3PO.sub.4

Further Components

[0032] The anticorrosive composition according to the present invention can comprise further components which can further improve the properties of the composition.

[0033] In one embodiment, the composition further comprises a hydrophobic agent comprising at least one silicone compound, such as silicone resin, such as a reactive silicone resin, such as a reactive silicone resin chosen from the group of polyalkylethoxysiloxane, polymethylethoxysiloxane, polyphenylethoxysiloxane, polyphenylsiloxane, polyphenylmethylsiloxane.

[0034] In one embodiment, the composition according to the present invention comprises a hydrophobic agent comprising polymethylethoxysiloxane in an amount of 30 to 60 percent by weight, and octyltriethoxysilane in an amount of 1 to 5 percent by weight, based on the total weight of the hydrophobic agent, an emulsifier and optionally trace amounts of ethanol.

[0035] In one embodiment, the composition according to the present invention comprises one or more alkali stable water dispersible surfactants.

[0036] In the framework of the present invention, surface active compounds are to be understood as compounds which lower the surface tension between two liquids, between a gas and a liquid, or between a liquid and a solid.

[0037] In another embodiment, the composition according to the present invention comprises one or more alkali stable water soluble surfactants.

[0038] In one embodiment, the composition according to the present invention comprises a surface-active compound selected from the list of soaps, surfactants, such as an alkali stable water dispersible surfactant, such as an alkali stable water soluble surfactant, such as an emulsifying surfactant.

[0039] In one embodiment, the composition according to the present invention comprises [0040] 100-500 g/l such as 150-300 g/l Na.sub.2SiO.sub.3 [0041] 2-50 g/l such as 10-20 g/l sebacic acid [0042] 20-80 g/l such as 30-60 g/l Na.sub.3PO.sub.4 [0043] 0.1-100 g/l surface-active compound, such as [0044] 0.05-50 g/l alkali stable surfactant and optional [0045] 0.1-100 g/l emulsifying co-surfactant.

[0046] In one embodiment, the composition according to the present invention comprises at least one siliconate compound, such as an organically modified water glass, such as alkalimetal organosiliconate, such as potassium methyl siliconate.

[0047] In one embodiment, the composition according to the present invention is an aqueous solution/dispersion and comprises 0.01-20 gram/litre, such as 0.05-15 gram/litre, such as 0.1-10 gram/litre silicone compound.

[0048] In one embodiment, the composition further comprises one or more water-miscible organic solvents.

[0049] In one embodiment, the water-miscible organic solvent is an alcohol, such as isopropanol.

[0050] In one embodiment, the composition according to the present invention comprises: [0051] 5-60 g/l, such as 25-45 g/l Na.sub.2SiO.sub.3 [0052] 0.5-5 g/l, such as 1.5-3.5 g/l sebacic acid [0053] 2-15 g/l, such as 4-10 g/l Na.sub.3PO.sub.4 [0054] 50-500 ml/l, such as 150-350 ml/l isopropyl alcohol.

[0055] In one embodiment, the composition further comprises one or more surfactants.

[0056] In one embodiment, the composition according to the present invention comprises: [0057] 100-500 g/l such as 150-300 g/l Na.sub.2SIO.sub.3 [0058] 2-50 g/l such as 10-20 g/l sebacic acid [0059] 20-80 g/l such as 30-60 g/l Na.sub.3PO.sub.4 [0060] 0.05-50 g/l alkali stable surfactant [0061] 0,1-100 g/l emulsifying co-surfactant

Use of the Composition

[0062] The present invention is also directed to the use of the composition described above for imparting anticorrosive properties to a material. There is no principal limitation to the materials on which the composition can be used for imparting anticorrosive properties.

[0063] In one embodiment, the present invention is directed to the use of the anticorrosive composition described above for imparting anticorrosive properties to a product selected from the group consisting of a mineral wool product, such as stone wool or glass wool, and other fibrous materials.

[0064] In one embodiment, the present invention is directed to the use of an anticorrosive composition described above for imparting anticorrosive properties to an insulation product selected from the group of a mineral wool insulation product, such as stone wool or glass wool insulation product, and an insulation product made from other fibrous materials.

[0065] In one embodiment, the use of the anticorrosive composition is such that the composition is dispersed in the product, such as a mineral wool product, such as a mineral wool insulation product or the other fibrous materials, such as the aerogel insulation product.

[0066] In one embodiment, this dispersion is such that dispersion takes place on a surface layer, such as a surface layer having a thickness of 0.5 to 10 cm, of the mineral wool product, such as mineral wool insulation product, or other fibrous materials, such as aerogel insulation product.

[0067] In one embodiment, the use is such that the product is selected from a pipe section, a roof product, a facade product, a mat, a wired mat.

Product

[0068] The present invention is also directed to a material, which has been treated by the anticorrosive composition described above.

[0069] In one embodiment, the product is a mineral wool product.

[0070] In one embodiment, the product is an aerogel.

[0071] In one embodiment, the product is a mineral wool product or other fibrous materials with improved anticorrosion properties, in particular improved anticorrosion under insulation properties.

[0072] The present invention is further illustrated by the following examples:

[0073] 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 Prorox PS960 with the anticorrosive composition according to the present invention has been compared with the anticorrosive performance of a standard stone wool pipe section Prorox PS960 without the anticorrosive composition according to the present invention.

Test Setup and Test Conditions

[0074] The test setup in general follows ASTM G189-07, but with the following modifications: [0075] PTFE spacers between samples have been replaced by special silicone O-rings [0076] Clamping of the test equipment and coupons is achieved using a spring compression system to counter for thermal expansion of the system [0077] Ring formed test coupons are 14.3 mm wide compared to the width in ASTM G189-07 of 6.35 mm

[0078] None of the modifications can be considered a relaxation compared to the test method and apparatus described in ASTM G189-07.

Equipment

[0079] The following simulation equipment is used: [0080] 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. [0081] b) O-rings for sealing and separation. [0082] c) Pipe insulation, ?160 ex., ?60 inside with and without corrosion inhibitor. [0083] d) Aluminium pipe jackets. [0084] e) Specially designed test rig consisting of two end pieces, between which test rings are mounted. [0085] f) Threaded rods mounted with coil springs to tighten the arrangement. The coil springs ensure that thermal extensions can be absorbed. [0086] g) Julabo Corio heating/cooling bath with circulation as well as pipe and hose connections. The bath is programmable according to the time/temperature control. [0087] 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. [0088] i) Control computer. [0089] j) Data logger for logging temperature during test. [0090] k) Test liquid delivery system/metering pumps with controllers. [0091] l) Silicone sealant. [0092] m) Insulation for heating pipes between heaters and installation.

[0093] 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.

Test Conditions

[0094] Two separate tests were conducted. The Conditions during the test were as follows:

Test 1:

[0095] 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 of 21 days

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 [0096] b) Test duration 21 cycles (21 days) [0097] c) Test solution is deionized water [0098] d) Test solution enters through the top of the insulation via two feed tubes placed 42.9 mm apart, see FIGS. 1 and 2 [0099] e) The insulation is drained via a centred hole in the bottom of the insulation, see FIG. 1 [0100] 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 [0101] 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:

[0102] 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 of 21 days

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

[0103] Two different concentrations of the anticorrosive composition were used in the two tests and were applied to the stone wool insulation with different techniques, however resulting in the same concentration of anticorrosive composition per cubic centimetre of treated pipe insulation.

Test 1:

[0104] 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: [0105] 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

[0106] 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: [0107] 1. 33,75 g of sodium silicate Na.sub.2SiO.sub.3 and let dissolve under stirring/shaking [0108] 2. 2,25 g of sebacic acid, and let dissolve under stirring or shaking [0109] 3. 6,75 g trisodium phosphate Na.sub.3PO.sub.4 and let dissolve

[0110] In the end 0,25 L IPA is to be used with each 0,75 L mixture.

[0111] 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.

[0112] The insulation sample, now treated with the anticorrosive composition is then tested for CUI performance as per above described test 1.

Test 2:

[0113] To apply the anticorrosive composition to a 500 mm long pipe insulation, with inner diameter of 60 mm, a total of 0,13 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: [0114] 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 emusifying co-surfactant+4 g/l alkali stable surfactant

[0115] All chemicals dissolved in demineralized water in the above order balanced to 1 litre.

[0116] 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.

[0117] The insulation sample now treated with the anticorrosive composition is then tested for CUI performance as per above described test 2.

Results

[0118] 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.

[0119] After removal of corrosion products, the extent of localised corrosion was estimated (if relevant), as well as measurement of pitting depth (if relevant).

[0120] The results are summarised in table 1 (test 1 with Prorox PS960 with corrosion inhibitor), table 2 (test 1 with Prorox PS960) and table 3 (test 2 with Prorox PS960 with corrosion inhibitor, and higher water injection during test)

[0121] Photos from test 1 of test coupons tested with Prorox PS960 with corrosion inhibitor prior to and after removal of deposits and corrosion products can be seen in FIGS. 4 to 7.

[0122] Photos from test 1 of test coupons tested with Prorox PS960 prior to and after removal of deposits and corrosion products can be seen in FIGS. 8 to 12.

[0123] Photos from test 2 of test coupons tested with Prorox PS960 with corrosion inhibitor prior to and after removal of deposits and corrosion products can be seen in FIGS. 13 to 20.

Test 1 Prorox PS960 with Corrosion Inhibitor

[0124] Regarding the results from testing with Prorox PS960 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.

[0125] On test coupon A21-6 one small diameter pit was detected.

[0126] 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.

[0127] During the 21 cycles of testing water draining from the test were measured to be slightly alkaline (app. pH 8-10).

TABLE-US-00003 TABLE 1 Prorox PS960 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

[0128] 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.

[0129] 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).

TABLE-US-00004 TABLE 2 Prorox PS960, 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 Prorox PS960 with Corrosion Inhibitor

[0130] The test where conducted in duplicate with a 40% higher water injection volume than in test 1.

[0131] 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.

[0132] 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.

[0133] During the 21 cycles of testing water draining from the test A&B were measured to be slightly alkaline (app. pH 8-10).

TABLE-US-00005 TABLE 3 Prorox PS960 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

[0134] 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 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.