CA1268676A - Anticorrosion coatings for porous concrete metal reinforcing structures - Google Patents
Anticorrosion coatings for porous concrete metal reinforcing structuresInfo
- Publication number
- CA1268676A CA1268676A CA000496003A CA496003A CA1268676A CA 1268676 A CA1268676 A CA 1268676A CA 000496003 A CA000496003 A CA 000496003A CA 496003 A CA496003 A CA 496003A CA 1268676 A CA1268676 A CA 1268676A
- Authority
- CA
- Canada
- Prior art keywords
- metal reinforcing
- diorganopolysiloxane
- reinforcing structures
- coating
- crosslinked
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 229910052751 metal Inorganic materials 0.000 title claims abstract description 22
- 239000002184 metal Substances 0.000 title claims abstract description 22
- 239000004567 concrete Substances 0.000 title claims abstract description 20
- 238000000576 coating method Methods 0.000 title claims abstract description 19
- 230000003014 reinforcing effect Effects 0.000 title claims abstract description 13
- 239000000203 mixture Substances 0.000 claims abstract description 36
- PPBRXRYQALVLMV-UHFFFAOYSA-N Styrene Chemical compound C=CC1=CC=CC=C1 PPBRXRYQALVLMV-UHFFFAOYSA-N 0.000 claims abstract description 28
- 229920005645 diorganopolysiloxane polymer Polymers 0.000 claims abstract description 20
- 239000011248 coating agent Substances 0.000 claims abstract description 16
- 229920001577 copolymer Polymers 0.000 claims abstract description 16
- 150000003254 radicals Chemical class 0.000 claims abstract description 8
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims abstract description 7
- 238000007334 copolymerization reaction Methods 0.000 claims abstract description 7
- 238000005260 corrosion Methods 0.000 claims abstract description 7
- 230000007797 corrosion Effects 0.000 claims abstract description 7
- 239000001257 hydrogen Substances 0.000 claims abstract description 7
- 229910052739 hydrogen Inorganic materials 0.000 claims abstract description 7
- 239000011203 carbon fibre reinforced carbon Substances 0.000 claims abstract description 6
- 229920001296 polysiloxane Polymers 0.000 claims abstract description 6
- 238000006482 condensation reaction Methods 0.000 claims abstract description 5
- 238000004132 cross linking Methods 0.000 claims abstract description 5
- CERQOIWHTDAKMF-UHFFFAOYSA-N Methacrylic acid Chemical compound CC(=C)C(O)=O CERQOIWHTDAKMF-UHFFFAOYSA-N 0.000 claims abstract description 4
- 238000000034 method Methods 0.000 claims description 8
- KPUWHANPEXNPJT-UHFFFAOYSA-N disiloxane Chemical compound [SiH3]O[SiH3] KPUWHANPEXNPJT-UHFFFAOYSA-N 0.000 claims description 7
- 238000009877 rendering Methods 0.000 claims 1
- 229920001971 elastomer Polymers 0.000 abstract description 5
- 239000000806 elastomer Substances 0.000 abstract description 5
- 239000012779 reinforcing material Substances 0.000 description 11
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 9
- 239000002253 acid Substances 0.000 description 5
- 150000002148 esters Chemical class 0.000 description 5
- 229910000077 silane Inorganic materials 0.000 description 5
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 4
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 4
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 4
- 239000004205 dimethyl polysiloxane Substances 0.000 description 4
- 235000013870 dimethyl polysiloxane Nutrition 0.000 description 4
- 239000007789 gas Substances 0.000 description 4
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 229920000435 poly(dimethylsiloxane) Polymers 0.000 description 4
- BLRPTPMANUNPDV-UHFFFAOYSA-N Silane Chemical compound [SiH4] BLRPTPMANUNPDV-UHFFFAOYSA-N 0.000 description 3
- CQEYYJKEWSMYFG-UHFFFAOYSA-N butyl acrylate Chemical compound CCCCOC(=O)C=C CQEYYJKEWSMYFG-UHFFFAOYSA-N 0.000 description 3
- -1 for example Chemical class 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- SOGAXMICEFXMKE-UHFFFAOYSA-N Butylmethacrylate Chemical compound CCCCOC(=O)C(C)=C SOGAXMICEFXMKE-UHFFFAOYSA-N 0.000 description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- BAPJBEWLBFYGME-UHFFFAOYSA-N Methyl acrylate Chemical compound COC(=O)C=C BAPJBEWLBFYGME-UHFFFAOYSA-N 0.000 description 2
- 125000005396 acrylic acid ester group Chemical group 0.000 description 2
- 239000007864 aqueous solution Substances 0.000 description 2
- 238000009833 condensation Methods 0.000 description 2
- 230000005494 condensation Effects 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 125000005397 methacrylic acid ester group Chemical group 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- 238000006116 polymerization reaction Methods 0.000 description 2
- 238000002360 preparation method Methods 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 239000011541 reaction mixture Substances 0.000 description 2
- 238000010992 reflux Methods 0.000 description 2
- 150000003839 salts Chemical class 0.000 description 2
- 235000012239 silicon dioxide Nutrition 0.000 description 2
- 239000000377 silicon dioxide Substances 0.000 description 2
- 239000011780 sodium chloride Substances 0.000 description 2
- OGZPYBBKQGPQNU-DABLZPOSSA-N (e)-n-[bis[[(e)-butan-2-ylideneamino]oxy]-methylsilyl]oxybutan-2-imine Chemical compound CC\C(C)=N\O[Si](C)(O\N=C(/C)CC)O\N=C(/C)CC OGZPYBBKQGPQNU-DABLZPOSSA-N 0.000 description 1
- VXEGSRKPIUDPQT-UHFFFAOYSA-N 4-[4-(4-methoxyphenyl)piperazin-1-yl]aniline Chemical compound C1=CC(OC)=CC=C1N1CCN(C=2C=CC(N)=CC=2)CC1 VXEGSRKPIUDPQT-UHFFFAOYSA-N 0.000 description 1
- JIGUQPWFLRLWPJ-UHFFFAOYSA-N Ethyl acrylate Chemical compound CCOC(=O)C=C JIGUQPWFLRLWPJ-UHFFFAOYSA-N 0.000 description 1
- PIICEJLVQHRZGT-UHFFFAOYSA-N Ethylenediamine Chemical compound NCCN PIICEJLVQHRZGT-UHFFFAOYSA-N 0.000 description 1
- 229910000640 Fe alloy Inorganic materials 0.000 description 1
- VVQNEPGJFQJSBK-UHFFFAOYSA-N Methyl methacrylate Chemical compound COC(=O)C(C)=C VVQNEPGJFQJSBK-UHFFFAOYSA-N 0.000 description 1
- 229910001294 Reinforcing steel Inorganic materials 0.000 description 1
- UKLDJPRMSDWDSL-UHFFFAOYSA-L [dibutyl(dodecanoyloxy)stannyl] dodecanoate Chemical compound CCCCCCCCCCCC(=O)O[Sn](CCCC)(CCCC)OC(=O)CCCCCCCCCCC UKLDJPRMSDWDSL-UHFFFAOYSA-L 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 150000001335 aliphatic alkanes Chemical class 0.000 description 1
- 125000001931 aliphatic group Chemical group 0.000 description 1
- 239000010426 asphalt Substances 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- GOAZMLKQUGCOPO-UHFFFAOYSA-N cetoxime Chemical compound C=1C=CC=CC=1N(CC(/N)=N/O)CC1=CC=CC=C1 GOAZMLKQUGCOPO-UHFFFAOYSA-N 0.000 description 1
- 229950011200 cetoxime Drugs 0.000 description 1
- 239000008199 coating composition Substances 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- SUPCQIBBMFXVTL-UHFFFAOYSA-N ethyl 2-methylprop-2-enoate Chemical compound CCOC(=O)C(C)=C SUPCQIBBMFXVTL-UHFFFAOYSA-N 0.000 description 1
- FKIRSCKRJJUCNI-UHFFFAOYSA-N ethyl 7-bromo-1h-indole-2-carboxylate Chemical compound C1=CC(Br)=C2NC(C(=O)OCC)=CC2=C1 FKIRSCKRJJUCNI-UHFFFAOYSA-N 0.000 description 1
- 239000000706 filtrate Substances 0.000 description 1
- 239000011381 foam concrete Substances 0.000 description 1
- 239000007792 gaseous phase Substances 0.000 description 1
- 238000007654 immersion Methods 0.000 description 1
- 230000006698 induction Effects 0.000 description 1
- 239000011256 inorganic filler Substances 0.000 description 1
- 229910003475 inorganic filler Inorganic materials 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000005055 methyl trichlorosilane Substances 0.000 description 1
- JLUFWMXJHAVVNN-UHFFFAOYSA-N methyltrichlorosilane Chemical compound C[Si](Cl)(Cl)Cl JLUFWMXJHAVVNN-UHFFFAOYSA-N 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 239000000178 monomer Substances 0.000 description 1
- PNJWIWWMYCMZRO-UHFFFAOYSA-N pent‐4‐en‐2‐one Natural products CC(=O)CC=C PNJWIWWMYCMZRO-UHFFFAOYSA-N 0.000 description 1
- BOQSSGDQNWEFSX-UHFFFAOYSA-N propan-2-yl 2-methylprop-2-enoate Chemical compound CC(C)OC(=O)C(C)=C BOQSSGDQNWEFSX-UHFFFAOYSA-N 0.000 description 1
- LYBIZMNPXTXVMV-UHFFFAOYSA-N propan-2-yl prop-2-enoate Chemical compound CC(C)OC(=O)C=C LYBIZMNPXTXVMV-UHFFFAOYSA-N 0.000 description 1
- NHARPDSAXCBDDR-UHFFFAOYSA-N propyl 2-methylprop-2-enoate Chemical compound CCCOC(=O)C(C)=C NHARPDSAXCBDDR-UHFFFAOYSA-N 0.000 description 1
- PNXMTCDJUBJHQJ-UHFFFAOYSA-N propyl prop-2-enoate Chemical compound CCCOC(=O)C=C PNXMTCDJUBJHQJ-UHFFFAOYSA-N 0.000 description 1
- 230000002787 reinforcement Effects 0.000 description 1
- 239000011369 resultant mixture Substances 0.000 description 1
- 238000005096 rolling process Methods 0.000 description 1
- 239000005049 silicon tetrachloride Substances 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
Classifications
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
- E04C5/00—Reinforcing elements, e.g. for concrete; Auxiliary elements therefor
- E04C5/01—Reinforcing elements of metal, e.g. with non-structural coatings
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/31504—Composite [nonstructural laminate]
- Y10T428/31652—Of asbestos
- Y10T428/31663—As siloxane, silicone or silane
Abstract
ANTICORROSION COATINGS FOR POROUS
CONCRETE METAL REINFORCING STRUCTURES
Abstract of the Disclosure The present invention relates to a corrosion resistant coating for metal reinforcing structures that are used in porous concrete which comprises coating the metal reinforcing struc-tures with an organopolysiloxane elastomer obtained by cross-linking a diorganopolysiloxane-based composition by the conden-sation reaction or by the addition of Si-bonded hydrogen to an aliphatic carbon-carbon double bond, in which the composition contains a copolymer that is obtained via a free radical copoly-merization of styrene and a(meth)acrylic acid ester in the pre-sence of the diorganopolysiloxane.
CONCRETE METAL REINFORCING STRUCTURES
Abstract of the Disclosure The present invention relates to a corrosion resistant coating for metal reinforcing structures that are used in porous concrete which comprises coating the metal reinforcing struc-tures with an organopolysiloxane elastomer obtained by cross-linking a diorganopolysiloxane-based composition by the conden-sation reaction or by the addition of Si-bonded hydrogen to an aliphatic carbon-carbon double bond, in which the composition contains a copolymer that is obtained via a free radical copoly-merization of styrene and a(meth)acrylic acid ester in the pre-sence of the diorganopolysiloxane.
Description
-1- Docket No. Wa-8429 Paper No. 1 0 ~.~
ANTICORROSION COATINGS FOR POROUS
CONCRETE ME~AL REINFORCING STRUCTURES
The present invention relates to anticorrosion coat-ings and more particularly relates to anticorrosion coatings for metal reinforcing struc-tures -that are used in porous concrete.
Back~round of the Invention .
Metallic reinforcing materials which are embedded in porous concrete such as metal bars or mesh have a tendency to corrode over a period of time in the presence of a corrosive medium such as aqueous solutions of metallic salts such as, for example, sodium chloride~
It is therefore an object of the present invention to provide a coating for metal reinforcing materials which will prevent corrosion of these materials when embedded in porous concrete. Another object of the present invention is to provide a coating for metal reinforcing materials which are used in porous concrete. Still another object of the present invention ~is to provide a coating for metal reinforcing structures which are used in porous concrete which is applied only once and that requires little or no energy for drying. A further object of the present invention is to provide a coating for metal rein-forcing materials that is thermally stable under relatively high~temperatures which are used in some processes for manufacturing porous concrete~ A further object of the present invention is to provide a coating that provides a high degree of protection against corrosion even when the coating on the metal reinforcin~
structures is~ relatively thin. ~ still further object of the present invention is to pxovide an organopolysiloxane elasto meric coating which protects porous concrete metal reinforcing materials against corrosion.
. .
: . -: ~ ::' ""; ' ' ~
6~7 Summary of the Invention The foregoing objects and others which will becomeapparent from the following description are accomplished in accordance with this invention, generally speaking, by providing an organopolysiloxane elastomeric coating for metal reinorcing materials that are used in porous concrete to prevent corrosion of the reinforcing materials, in which the elastomeric coatinq is a crosslin~ed diorganopolysiloxane containing a copolymer obtained from the free radical copolymerization of styrene and a (meth~crylic acid ester in the presence of the diorganopolysi-loxane.
Descri~tion of the Invention The organopolysiloxane elastomers used to coat the metal reinforcing materials used in porous concrete are com-positions which can be crosslinked by the condensation reactionor ~y the addition of Si-bonded hydrogen to an aliphatic carbon-carbon double bond. These elastomers are based on diorganopoly-siloxanes containing a copolymer that has been obtained from the copolymerization of styrene and a(meth~crylic acid ester in the presence of the diorganopolysiloxane by mean~ of free radicals.
These compositions may be single compone~t systems, i.e., compo-sitions which are available commercially as a single package; or they may be two-component systems, i.e., compositions which are obtained ~y mixing at least two components more or less immedi-25 ately prior to the composition being applied to the reinforcingelements which axe to be protected against corrosion.
The diorganopolysiloxane-based compositions containing a copolymer which is obtained from the copolymerization of styrene and a(meth~crylic acid ester by mean~ of free radicals in the presence of the diorganopolysiloxane, and which can be crosslinked to form elastomer~, by the condensation reaction or by the addition o~ Si-honded hydrogen to an aliphatic carbon-carbon double bond are well known and have been previously described in ~he art~ The camposi$ions and their methods of preparation are described, for example~ in U. S. Patent No.
3,555,109 to Getson; U. SO Patent No. 3,7~6,875 to Getson; U. S.
Paten~ No. 4,032,499 to Kxeuzer et al; U. S. Patent No. 4,014,B51 to Bluestein; and in UO S. Patent No . 4 ,13B, 387 to Bluestein .
, , ~ , :, : :
., ', ~ :'',',,,' :,. -.; ' : .
.. ..
..... ,.~. .
3L~ 7~
It is preferred that the compositions based on a dior-ganopolysiloxane containing a copolymer obtained from the copolymerization of styrene and a(meth`acrylic acid ester by means of free radicals in the presence of the diorganopoly-siloxane, which can be crosslinked by the condensation reactionor by the addition of Si-bonded hydrogen to an aliphatic carbon-carbon double bond, comprise rom 20 to 80 percen-t by weight of the diorganopolysiloxane, based on the total weight of the diorganopolysiloxane and the copolymer consisting o~ styrene and methacrylic acid ester.
Moreover, it is preferred that the copolymers of styrene and(meth~crylic acid ester which are formed in the presence of the diorganopolysiloxane contain from 35 to ~0 percent by weiyht of units that are derived from styrene and that the remainder consist of units deri~ed from methacrylic acid ester.
The preferred copolymers which are produced in the presence of the diorganopolysiloxane are those consisting of styrene and n-butylacrylate. ~Iowever, the n-butylacrylate may also be at least partially subs-tituted by, for example, methyl-acrylate, ethylacrylate, n-propylacrylate, isopropylacrylate, sec-butylacryalte, methylmethacrylate, ethylmethacrylate, n-propylmethacrylate, isopropylmethacrylate, n-butylmethacrylate or sec-butylmethacrylate or a mixture of two or more of these ~et~acrylic acid esters.
Because of their availabillty, it is preEerred that at least 80 percent of the number of the SiC-bonded organic radicals of the diorganopolysiloxanes in whose presence the copolymers consisting of styrene and(meth)acrylic acid ester are prepared, be methyl radicals.
The anticorrosion coating compositions of this inven-tion contain the diorganopolysiloxane which can be crosslinked by the condensation reaction or by the addition of Si-bonded hydrogen to an aliphatic carbon-carhon double bond, the copoly-mer of styrene and ~eth~acrylic acid ester which is prepared inthe presence of the diorganopolysiloxane, crosslinking agen~s such as methyltris-tmethylethylketoximo)~silane and a cross-linking catalyst such as di-n-butyltin dilaurate. In addition, , ' ~ :
., .~.
-~4 the compositions may also contain additiona] materials, such as diorganopolysiloxanes, especially a dimethylpolysiloxane having an Si~bonded hydroxyl group in each of its terminal units and which has a viscosity of 50 to 100,n00 mPa.s at 25C. These diorganopolysiloxanes are preferably prescnt in the compositions in an amount of from 10 to 80 percent by weight, based on the total weight of the composition. Other additives ~hich may be present in the coatin~ compositions are inorganic fillers, such as pyrogenically produced silicon dioxide and or~anic solvents.
The composi-tions of this invention may be applied to the metal reinforcing materials by any method that is suitable for applying liquid or paste-like substances. These compositions may be applied by immersion, spraying, coating, pouring or rolling. After the compositions have been applied to the metal reinforcing materials, they are crosslinked to form organopoly-siloxane elastomers. Crosslinking may take place at room temper-ature, or it may be accelerated by heating to between 50 and 150C, and more preferably about 70C, for example, by induction heating. It is preferable that the coatings be applied at a 20 thickness of from about 30 to 200 microns, and more preferably from about 60 to 80 microns.
It is preferred that the metal reinforcing materials which are coated with the diorganopolysiloxane-based compositions be made of iron or iron alloys, especially reinforcing steel.
These coated metal reinforcing materials are employed in porous concrete such as gas concrete, foam concrete or li~htweight concrete.
The followin~ example describes a preferred embodiment of this inven-tion.
Example (a) To a 4-liter flask equipped with an agitator, a reflux condenser, a thermometer and a dropping funnel, and con-taining 330 g (4.36 mol) of methylethyl]cetoxime, 14~ g (2.33mol) of ethylenediamine and 1.5 liter of toluene is added over a period of 2~ hours, a mixture consistin~ of 56.7 g (0.33 mol) of silicon tetrachloride and 150 g (1 mol) oE methyltrichlorosilane in 375 g of toluene. The contents of -the flask increases to about 60C. After the addition of the silane mixture, stirring -- . .
.: .
- ' ' . `
, ~ :
7~
.s continued for an additional 2 hours and then the mix-ture is filtered to remov~ the amine-hydrochloride. Toluene and other volatile materials are then remove~ from the filtrate in a rotating evaporator at about 16 hPa (abs.). The product consists of 385 g o~ a clear mixture that is liquid at room temperature and which consists of methyltris-(methylethylketoximo)-silane and tetra(methylethylketoxirno)-silane.
(b) A polymerization reactor having an inside diameter of 312 mm which is equipped with a 50 rpm anchor stirrer having a maximum diameter of 295 mm and in addition a gas inlet port, a reflux condenser and temperature recorder is us~d -to heat over a period of 7 hours under an atmosphere of nitrogen, and with the aid of an aqueous s-team jacket that is main-tained at a temperature of 100C, a mixture comprising 5.2 kg (50 mol) of styrene, 4.2 kg (33 mol) of n-butylacrylate, 4.04 kg of dimethylpolysiloxane having an Si-bonded hydroxyl group in each of its -terminal units and having a viscosity of 430 mPa.s at 25C, 0.8 kg of water and 0.141 kg of 1,1-di-tert-butylperoxy-3,3,5-trimethylcyclohexane.
The contents of the polymerization reactor is maintained at a temperature at or below 97C.
In order to remov~ unreacted monomers and water, nitrogen is then blown through the reaction mixture at a tem-perature between 100 and 130C and subsequently the reaction mixture is heated to a temperature of 130C for 3 hours at 16 hPa (abs.~. The viscosity of the resultant mixture is 22,000 mPa.s at 25C.
(c) About 125 parts by weight of the mixture prepared in (b) above are mixed in the following sequence with 11 parts by wei~ht of a dimethylpolysiloxane having an Si-bonded hydroxyl group in each of its terminal units and having a viscosity of 500 mPa.s at 25~C, 4 parts by weight of a dimethylpolysiloxane having an Si-bonded hydroxyl group in each of its terminal units and having a viscosity of 20,000 mPa.s at 25C, 13 parts by weight of a mixture containing one part by weight of silane mixture whose preparation was described in (a) above, one part by weight of methyltris-~ethylethylketoximo)-silane and 4 parts by weight of silicon dioxide that was produced in the gaseous phase and which has a BET-surface area of 200 m2/g. Air bubbles are :,-~ 6--~vacua-ted from the resultant composition, and -then 41 parts by weight of an alkane mixture having a boiling range of from 100 to 140C at 1,020 hPa (abs.) are mixe-l in the compositionO The di~spersion thus obtained has a viscosity of about 25,000 mPa.s at 25C.
(d) Metal reinforcing rods are coated with the composition prepared in (c) above, and then exposed to atmospheric air for 7 days. The coated rods are then incorporated in gas concrete blocks which are then immersed for a period of 2 hours at a time, over a period of 3 days for a total of 10 times in a 3 percent by weight aqueous solution of sodium chloride and then air-dried. Similar gas concrete bloc~s containing untreated reinforcin~ rods are exposed to salt water and -thereafter the reinforcement rods are removed from the concrete and the extent of rust on the reinforcing rods determined.
The results are shown in the following table.
T L
CoatingRust as a percentage thicknessof rust covering ~ _ micronsuntreated rods to Method (d) 70 Less than 1 Prepared according 100 Less than 1 to method (d~
Bitumen* 300 2 to 7 Bitumenlatex* 300 2 to 7 Cementbitumen* 500 1 to 5 Cementlatex* 500 1 to 5 Commercially available products.
' ;,~ . ~
- ,:
ANTICORROSION COATINGS FOR POROUS
CONCRETE ME~AL REINFORCING STRUCTURES
The present invention relates to anticorrosion coat-ings and more particularly relates to anticorrosion coatings for metal reinforcing struc-tures -that are used in porous concrete.
Back~round of the Invention .
Metallic reinforcing materials which are embedded in porous concrete such as metal bars or mesh have a tendency to corrode over a period of time in the presence of a corrosive medium such as aqueous solutions of metallic salts such as, for example, sodium chloride~
It is therefore an object of the present invention to provide a coating for metal reinforcing materials which will prevent corrosion of these materials when embedded in porous concrete. Another object of the present invention is to provide a coating for metal reinforcing materials which are used in porous concrete. Still another object of the present invention ~is to provide a coating for metal reinforcing structures which are used in porous concrete which is applied only once and that requires little or no energy for drying. A further object of the present invention is to provide a coating for metal rein-forcing materials that is thermally stable under relatively high~temperatures which are used in some processes for manufacturing porous concrete~ A further object of the present invention is to provide a coating that provides a high degree of protection against corrosion even when the coating on the metal reinforcin~
structures is~ relatively thin. ~ still further object of the present invention is to pxovide an organopolysiloxane elasto meric coating which protects porous concrete metal reinforcing materials against corrosion.
. .
: . -: ~ ::' ""; ' ' ~
6~7 Summary of the Invention The foregoing objects and others which will becomeapparent from the following description are accomplished in accordance with this invention, generally speaking, by providing an organopolysiloxane elastomeric coating for metal reinorcing materials that are used in porous concrete to prevent corrosion of the reinforcing materials, in which the elastomeric coatinq is a crosslin~ed diorganopolysiloxane containing a copolymer obtained from the free radical copolymerization of styrene and a (meth~crylic acid ester in the presence of the diorganopolysi-loxane.
Descri~tion of the Invention The organopolysiloxane elastomers used to coat the metal reinforcing materials used in porous concrete are com-positions which can be crosslinked by the condensation reactionor ~y the addition of Si-bonded hydrogen to an aliphatic carbon-carbon double bond. These elastomers are based on diorganopoly-siloxanes containing a copolymer that has been obtained from the copolymerization of styrene and a(meth~crylic acid ester in the presence of the diorganopolysiloxane by mean~ of free radicals.
These compositions may be single compone~t systems, i.e., compo-sitions which are available commercially as a single package; or they may be two-component systems, i.e., compositions which are obtained ~y mixing at least two components more or less immedi-25 ately prior to the composition being applied to the reinforcingelements which axe to be protected against corrosion.
The diorganopolysiloxane-based compositions containing a copolymer which is obtained from the copolymerization of styrene and a(meth~crylic acid ester by mean~ of free radicals in the presence of the diorganopolysiloxane, and which can be crosslinked to form elastomer~, by the condensation reaction or by the addition o~ Si-honded hydrogen to an aliphatic carbon-carbon double bond are well known and have been previously described in ~he art~ The camposi$ions and their methods of preparation are described, for example~ in U. S. Patent No.
3,555,109 to Getson; U. SO Patent No. 3,7~6,875 to Getson; U. S.
Paten~ No. 4,032,499 to Kxeuzer et al; U. S. Patent No. 4,014,B51 to Bluestein; and in UO S. Patent No . 4 ,13B, 387 to Bluestein .
, , ~ , :, : :
., ', ~ :'',',,,' :,. -.; ' : .
.. ..
..... ,.~. .
3L~ 7~
It is preferred that the compositions based on a dior-ganopolysiloxane containing a copolymer obtained from the copolymerization of styrene and a(meth`acrylic acid ester by means of free radicals in the presence of the diorganopoly-siloxane, which can be crosslinked by the condensation reactionor by the addition of Si-bonded hydrogen to an aliphatic carbon-carbon double bond, comprise rom 20 to 80 percen-t by weight of the diorganopolysiloxane, based on the total weight of the diorganopolysiloxane and the copolymer consisting o~ styrene and methacrylic acid ester.
Moreover, it is preferred that the copolymers of styrene and(meth~crylic acid ester which are formed in the presence of the diorganopolysiloxane contain from 35 to ~0 percent by weiyht of units that are derived from styrene and that the remainder consist of units deri~ed from methacrylic acid ester.
The preferred copolymers which are produced in the presence of the diorganopolysiloxane are those consisting of styrene and n-butylacrylate. ~Iowever, the n-butylacrylate may also be at least partially subs-tituted by, for example, methyl-acrylate, ethylacrylate, n-propylacrylate, isopropylacrylate, sec-butylacryalte, methylmethacrylate, ethylmethacrylate, n-propylmethacrylate, isopropylmethacrylate, n-butylmethacrylate or sec-butylmethacrylate or a mixture of two or more of these ~et~acrylic acid esters.
Because of their availabillty, it is preEerred that at least 80 percent of the number of the SiC-bonded organic radicals of the diorganopolysiloxanes in whose presence the copolymers consisting of styrene and(meth)acrylic acid ester are prepared, be methyl radicals.
The anticorrosion coating compositions of this inven-tion contain the diorganopolysiloxane which can be crosslinked by the condensation reaction or by the addition of Si-bonded hydrogen to an aliphatic carbon-carhon double bond, the copoly-mer of styrene and ~eth~acrylic acid ester which is prepared inthe presence of the diorganopolysiloxane, crosslinking agen~s such as methyltris-tmethylethylketoximo)~silane and a cross-linking catalyst such as di-n-butyltin dilaurate. In addition, , ' ~ :
., .~.
-~4 the compositions may also contain additiona] materials, such as diorganopolysiloxanes, especially a dimethylpolysiloxane having an Si~bonded hydroxyl group in each of its terminal units and which has a viscosity of 50 to 100,n00 mPa.s at 25C. These diorganopolysiloxanes are preferably prescnt in the compositions in an amount of from 10 to 80 percent by weight, based on the total weight of the composition. Other additives ~hich may be present in the coatin~ compositions are inorganic fillers, such as pyrogenically produced silicon dioxide and or~anic solvents.
The composi-tions of this invention may be applied to the metal reinforcing materials by any method that is suitable for applying liquid or paste-like substances. These compositions may be applied by immersion, spraying, coating, pouring or rolling. After the compositions have been applied to the metal reinforcing materials, they are crosslinked to form organopoly-siloxane elastomers. Crosslinking may take place at room temper-ature, or it may be accelerated by heating to between 50 and 150C, and more preferably about 70C, for example, by induction heating. It is preferable that the coatings be applied at a 20 thickness of from about 30 to 200 microns, and more preferably from about 60 to 80 microns.
It is preferred that the metal reinforcing materials which are coated with the diorganopolysiloxane-based compositions be made of iron or iron alloys, especially reinforcing steel.
These coated metal reinforcing materials are employed in porous concrete such as gas concrete, foam concrete or li~htweight concrete.
The followin~ example describes a preferred embodiment of this inven-tion.
Example (a) To a 4-liter flask equipped with an agitator, a reflux condenser, a thermometer and a dropping funnel, and con-taining 330 g (4.36 mol) of methylethyl]cetoxime, 14~ g (2.33mol) of ethylenediamine and 1.5 liter of toluene is added over a period of 2~ hours, a mixture consistin~ of 56.7 g (0.33 mol) of silicon tetrachloride and 150 g (1 mol) oE methyltrichlorosilane in 375 g of toluene. The contents of -the flask increases to about 60C. After the addition of the silane mixture, stirring -- . .
.: .
- ' ' . `
, ~ :
7~
.s continued for an additional 2 hours and then the mix-ture is filtered to remov~ the amine-hydrochloride. Toluene and other volatile materials are then remove~ from the filtrate in a rotating evaporator at about 16 hPa (abs.). The product consists of 385 g o~ a clear mixture that is liquid at room temperature and which consists of methyltris-(methylethylketoximo)-silane and tetra(methylethylketoxirno)-silane.
(b) A polymerization reactor having an inside diameter of 312 mm which is equipped with a 50 rpm anchor stirrer having a maximum diameter of 295 mm and in addition a gas inlet port, a reflux condenser and temperature recorder is us~d -to heat over a period of 7 hours under an atmosphere of nitrogen, and with the aid of an aqueous s-team jacket that is main-tained at a temperature of 100C, a mixture comprising 5.2 kg (50 mol) of styrene, 4.2 kg (33 mol) of n-butylacrylate, 4.04 kg of dimethylpolysiloxane having an Si-bonded hydroxyl group in each of its -terminal units and having a viscosity of 430 mPa.s at 25C, 0.8 kg of water and 0.141 kg of 1,1-di-tert-butylperoxy-3,3,5-trimethylcyclohexane.
The contents of the polymerization reactor is maintained at a temperature at or below 97C.
In order to remov~ unreacted monomers and water, nitrogen is then blown through the reaction mixture at a tem-perature between 100 and 130C and subsequently the reaction mixture is heated to a temperature of 130C for 3 hours at 16 hPa (abs.~. The viscosity of the resultant mixture is 22,000 mPa.s at 25C.
(c) About 125 parts by weight of the mixture prepared in (b) above are mixed in the following sequence with 11 parts by wei~ht of a dimethylpolysiloxane having an Si-bonded hydroxyl group in each of its terminal units and having a viscosity of 500 mPa.s at 25~C, 4 parts by weight of a dimethylpolysiloxane having an Si-bonded hydroxyl group in each of its terminal units and having a viscosity of 20,000 mPa.s at 25C, 13 parts by weight of a mixture containing one part by weight of silane mixture whose preparation was described in (a) above, one part by weight of methyltris-~ethylethylketoximo)-silane and 4 parts by weight of silicon dioxide that was produced in the gaseous phase and which has a BET-surface area of 200 m2/g. Air bubbles are :,-~ 6--~vacua-ted from the resultant composition, and -then 41 parts by weight of an alkane mixture having a boiling range of from 100 to 140C at 1,020 hPa (abs.) are mixe-l in the compositionO The di~spersion thus obtained has a viscosity of about 25,000 mPa.s at 25C.
(d) Metal reinforcing rods are coated with the composition prepared in (c) above, and then exposed to atmospheric air for 7 days. The coated rods are then incorporated in gas concrete blocks which are then immersed for a period of 2 hours at a time, over a period of 3 days for a total of 10 times in a 3 percent by weight aqueous solution of sodium chloride and then air-dried. Similar gas concrete bloc~s containing untreated reinforcin~ rods are exposed to salt water and -thereafter the reinforcement rods are removed from the concrete and the extent of rust on the reinforcing rods determined.
The results are shown in the following table.
T L
CoatingRust as a percentage thicknessof rust covering ~ _ micronsuntreated rods to Method (d) 70 Less than 1 Prepared according 100 Less than 1 to method (d~
Bitumen* 300 2 to 7 Bitumenlatex* 300 2 to 7 Cementbitumen* 500 1 to 5 Cementlatex* 500 1 to 5 Commercially available products.
' ;,~ . ~
- ,:
Claims (6)
PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. An anticorrosive coating for metal reinforcing structures which comprises metal reinforcing structures having an organopolysiloxane elastomeric coating thereon, said oryano-polysiloxane elastomeric coating is a crosslinked diorganopoly-siloxane copolymeric composition which is obtained from the free radical copolymerization of styrene and a(meth)acrylic acid ester in the presence of the diorganopolysiloxane.
2. The coating of claim 1, wherein the diorganopoly-siloxane copolymeric composition is crosslinked by a condensation reaction.
3. The coating of claim 1, wherein the diorganopoly-siloxane copolymeric composition is crosslinked by the addition of Si-bonded hydrogen to an aliphatic carbon-carbon double bond.
4. A process for rendering porous concrete metal reinforcing structures resistant to corrosion which comprises applying a crosslinkable diorganopolysiloxane copolymeric compo-sition which is obtained from the free radical copolymerization of styrene and(meth)acrylic acid ester in the presence of the diorganopolysiloxane to the reinforcing structures and there-after crosslinking the diorganopolysiloxane copolymeric compo-sition.
5. The process of claim 4, wherein the diorganopoly-siloxane copolymeric composition is crosslinked by a condensa-tion reaction.
6. The process of claim 4, wherein the diorganopoly-siloxane copolymeric composition is crosslinked by the addition of Si-bonded hydrogen to an aliphatic carbon-carbon double bond.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP3503276.6 | 1985-01-31 | ||
| DE19853503276 DE3503276A1 (en) | 1985-01-31 | 1985-01-31 | REINFORCEMENT ELEMENTS PROTECTED BY CORROSION AGAINST CORROSION OR IN PORO CONCRETE |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1268676A true CA1268676A (en) | 1990-05-08 |
Family
ID=6261303
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000496003A Expired CA1268676A (en) | 1985-01-31 | 1985-11-22 | Anticorrosion coatings for porous concrete metal reinforcing structures |
Country Status (5)
| Country | Link |
|---|---|
| US (1) | US4649066A (en) |
| EP (1) | EP0189890A3 (en) |
| JP (1) | JPS61181876A (en) |
| CA (1) | CA1268676A (en) |
| DE (1) | DE3503276A1 (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CH674752A5 (en) * | 1988-03-18 | 1990-07-13 | Proceq Sa | |
| DE3901734A1 (en) * | 1988-03-21 | 1989-10-05 | Bauakademie Ddr | Aqueous anticorrosion composition for steel reinforcements of autoclaved silicate concretes |
| DE4023226C1 (en) * | 1990-07-21 | 1992-01-23 | Institut Fuer Baustoffpruefung Waldkirch Gmbh, 7808 Waldkirch, De | |
| DE102004052420A1 (en) * | 2004-10-28 | 2006-05-04 | Wacker Chemie Ag | Chromate-free preparation for anti-corrosive coatings on metals |
| US9734878B1 (en) * | 2016-02-15 | 2017-08-15 | Qualcomm Incorporated | Systems and methods for individually configuring dynamic random access memories sharing a common command access bus |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB829051A (en) * | 1958-01-09 | 1960-02-24 | Siporex Int Ab | Improvements in the manufacture of reinforced light-weight concrete |
| US3555109A (en) * | 1967-09-08 | 1971-01-12 | Stauffer Wacker Silicone Corp | In situ generation of unique particulate matter in organopolysiloxanes |
| GB1589064A (en) * | 1977-01-12 | 1981-05-07 | Goldschmidt Ag Th | Process for the manufacture of organopolysiloxanes |
| US4292423A (en) * | 1979-04-19 | 1981-09-29 | Wacker-Chemie Gmbh | Process for the preparation of organopolysiloxanes |
| JPS58127769A (en) * | 1982-01-25 | 1983-07-29 | Hitachi Ltd | Prevention of corrosion fatigue failure of ferroalloy structural material |
| DE3216969A1 (en) * | 1982-05-06 | 1983-11-10 | Basf Farben + Fasern Ag, 2000 Hamburg | METHOD FOR PRODUCING A CORROSION PROTECTIVE COATING |
| US4435472A (en) * | 1982-08-27 | 1984-03-06 | Pennwalt Corporation | Adherent, acid cured resin protective coatings for concrete and steel |
| DE3303649A1 (en) * | 1983-02-03 | 1984-08-09 | Wacker-Chemie GmbH, 8000 München | EXCLUDING WATER STORAGE CROSS-LINKABLE DIMENSIONS WHEN THE WATER ACCESSES AT ROOM TEMPERATURE |
| DE3406266A1 (en) * | 1984-02-21 | 1985-08-29 | Wacker-Chemie GmbH, 8000 München | METHOD FOR PRODUCING PROTECTIVE COATINGS ON ASPHALT CONCRETE COATINGS AND COATED COATINGS |
-
1985
- 1985-01-31 DE DE19853503276 patent/DE3503276A1/en not_active Withdrawn
- 1985-11-14 US US06/798,048 patent/US4649066A/en not_active Expired - Fee Related
- 1985-11-22 CA CA000496003A patent/CA1268676A/en not_active Expired
-
1986
- 1986-01-28 EP EP19860101072 patent/EP0189890A3/en not_active Withdrawn
- 1986-01-30 JP JP61016982A patent/JPS61181876A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| EP0189890A2 (en) | 1986-08-06 |
| JPS61181876A (en) | 1986-08-14 |
| US4649066A (en) | 1987-03-10 |
| JPS6343433B2 (en) | 1988-08-30 |
| EP0189890A3 (en) | 1988-01-27 |
| DE3503276A1 (en) | 1986-08-07 |
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