CA1117705A - Corrosion-inhibiting pigment based on phosphate - Google Patents
Corrosion-inhibiting pigment based on phosphateInfo
- Publication number
- CA1117705A CA1117705A CA000339536A CA339536A CA1117705A CA 1117705 A CA1117705 A CA 1117705A CA 000339536 A CA000339536 A CA 000339536A CA 339536 A CA339536 A CA 339536A CA 1117705 A CA1117705 A CA 1117705A
- Authority
- CA
- Canada
- Prior art keywords
- corrosion
- pigment
- inhibiting
- phosphate
- iron
- 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
- 239000000049 pigment Substances 0.000 title claims abstract description 40
- 230000007797 corrosion Effects 0.000 title claims abstract description 30
- 238000005260 corrosion Methods 0.000 title claims abstract description 30
- 230000002401 inhibitory effect Effects 0.000 title claims abstract description 25
- 229910019142 PO4 Inorganic materials 0.000 title claims abstract description 10
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 title claims abstract description 5
- 239000010452 phosphate Substances 0.000 title claims abstract description 5
- 239000000203 mixture Substances 0.000 claims abstract description 18
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 12
- 229910000640 Fe alloy Inorganic materials 0.000 claims abstract description 7
- 229910052742 iron Inorganic materials 0.000 claims abstract description 6
- MHJAJDCZWVHCPF-UHFFFAOYSA-L dimagnesium phosphate Chemical compound [Mg+2].OP([O-])([O-])=O MHJAJDCZWVHCPF-UHFFFAOYSA-L 0.000 claims abstract description 3
- FUFJGUQYACFECW-UHFFFAOYSA-L calcium hydrogenphosphate Chemical compound [Ca+2].OP([O-])([O-])=O FUFJGUQYACFECW-UHFFFAOYSA-L 0.000 claims abstract 2
- 235000019700 dicalcium phosphate Nutrition 0.000 claims abstract 2
- XLYOFNOQVPJJNP-ZSJDYOACSA-N heavy water Substances [2H]O[2H] XLYOFNOQVPJJNP-ZSJDYOACSA-N 0.000 claims abstract 2
- 235000021317 phosphate Nutrition 0.000 claims description 6
- 150000001875 compounds Chemical class 0.000 claims description 3
- 150000003013 phosphoric acid derivatives Chemical group 0.000 claims description 3
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 claims description 2
- 239000011575 calcium Substances 0.000 claims description 2
- 229910052791 calcium Inorganic materials 0.000 claims description 2
- 239000011777 magnesium Substances 0.000 claims description 2
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 claims 1
- 229910052749 magnesium Inorganic materials 0.000 claims 1
- 238000010422 painting Methods 0.000 abstract description 5
- 239000004606 Fillers/Extenders Substances 0.000 abstract description 3
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 description 6
- 239000003795 chemical substances by application Substances 0.000 description 6
- 229910052751 metal Inorganic materials 0.000 description 6
- 239000002184 metal Substances 0.000 description 6
- LRHPLDYGYMQRHN-UHFFFAOYSA-N N-Butanol Chemical compound CCCCO LRHPLDYGYMQRHN-UHFFFAOYSA-N 0.000 description 4
- TZCXTZWJZNENPQ-UHFFFAOYSA-L barium sulfate Chemical compound [Ba+2].[O-]S([O-])(=O)=O TZCXTZWJZNENPQ-UHFFFAOYSA-L 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 230000002411 adverse Effects 0.000 description 3
- 239000011230 binding agent Substances 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 3
- 239000001506 calcium phosphate Substances 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 239000000945 filler Substances 0.000 description 3
- 238000005755 formation reaction Methods 0.000 description 3
- 150000003839 salts Chemical class 0.000 description 3
- 239000007921 spray Substances 0.000 description 3
- 239000000454 talc Substances 0.000 description 3
- 229910052623 talc Inorganic materials 0.000 description 3
- 238000003466 welding Methods 0.000 description 3
- 239000011787 zinc oxide Substances 0.000 description 3
- 229910000165 zinc phosphate Inorganic materials 0.000 description 3
- ZNQVEEAIQZEUHB-UHFFFAOYSA-N 2-ethoxyethanol Chemical compound CCOCCO ZNQVEEAIQZEUHB-UHFFFAOYSA-N 0.000 description 2
- 235000019739 Dicalciumphosphate Nutrition 0.000 description 2
- 239000004129 EU approved improving agent Substances 0.000 description 2
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 2
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 2
- 229920000180 alkyd Polymers 0.000 description 2
- SVPXDRXYRYOSEX-UHFFFAOYSA-N bentoquatam Chemical compound O.O=[Si]=O.O=[Al]O[Al]=O SVPXDRXYRYOSEX-UHFFFAOYSA-N 0.000 description 2
- 229910000389 calcium phosphate Inorganic materials 0.000 description 2
- 235000011010 calcium phosphates Nutrition 0.000 description 2
- ZCDOYSPFYFSLEW-UHFFFAOYSA-N chromate(2-) Chemical class [O-][Cr]([O-])(=O)=O ZCDOYSPFYFSLEW-UHFFFAOYSA-N 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- GUJOJGAPFQRJSV-UHFFFAOYSA-N dialuminum;dioxosilane;oxygen(2-);hydrate Chemical compound O.[O-2].[O-2].[O-2].[Al+3].[Al+3].O=[Si]=O.O=[Si]=O.O=[Si]=O.O=[Si]=O GUJOJGAPFQRJSV-UHFFFAOYSA-N 0.000 description 2
- 235000019791 dimagnesium phosphate Nutrition 0.000 description 2
- OGQYPPBGSLZBEG-UHFFFAOYSA-N dimethyl(dioctadecyl)azanium Chemical compound CCCCCCCCCCCCCCCCCC[N+](C)(C)CCCCCCCCCCCCCCCCCC OGQYPPBGSLZBEG-UHFFFAOYSA-N 0.000 description 2
- 238000011156 evaluation Methods 0.000 description 2
- 239000004137 magnesium phosphate Substances 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- 229910052901 montmorillonite Inorganic materials 0.000 description 2
- 231100000252 nontoxic Toxicity 0.000 description 2
- 230000003000 nontoxic effect Effects 0.000 description 2
- 230000001681 protective effect Effects 0.000 description 2
- 239000010936 titanium Substances 0.000 description 2
- 229910052719 titanium Inorganic materials 0.000 description 2
- QORWJWZARLRLPR-UHFFFAOYSA-H tricalcium bis(phosphate) Chemical compound [Ca+2].[Ca+2].[Ca+2].[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O QORWJWZARLRLPR-UHFFFAOYSA-H 0.000 description 2
- LRXTYHSAJDENHV-UHFFFAOYSA-H zinc phosphate Chemical compound [Zn+2].[Zn+2].[Zn+2].[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O LRXTYHSAJDENHV-UHFFFAOYSA-H 0.000 description 2
- 239000005909 Kieselgur Substances 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- 238000007605 air drying Methods 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 229910052787 antimony Inorganic materials 0.000 description 1
- WATWJIUSRGPENY-UHFFFAOYSA-N antimony atom Chemical compound [Sb] WATWJIUSRGPENY-UHFFFAOYSA-N 0.000 description 1
- 239000007900 aqueous suspension Substances 0.000 description 1
- 150000004649 carbonic acid derivatives Chemical class 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000004927 clay Substances 0.000 description 1
- 239000008199 coating composition Substances 0.000 description 1
- 238000002425 crystallisation Methods 0.000 description 1
- 230000008025 crystallization Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- NEFBYIFKOOEVPA-UHFFFAOYSA-K dicalcium phosphate Chemical compound [Ca+2].[Ca+2].[O-]P([O-])([O-])=O NEFBYIFKOOEVPA-UHFFFAOYSA-K 0.000 description 1
- 229910000390 dicalcium phosphate Inorganic materials 0.000 description 1
- 229940038472 dicalcium phosphate Drugs 0.000 description 1
- 229910000395 dimagnesium phosphate Inorganic materials 0.000 description 1
- ILLRQJVNDWDWBA-UHFFFAOYSA-K dimagnesium;phosphate Chemical class [Mg+2].[Mg+2].[O-]P([O-])([O-])=O ILLRQJVNDWDWBA-UHFFFAOYSA-K 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- 230000001939 inductive effect Effects 0.000 description 1
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 1
- 239000004922 lacquer Substances 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- GVALZJMUIHGIMD-UHFFFAOYSA-H magnesium phosphate Chemical class [Mg+2].[Mg+2].[Mg+2].[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O GVALZJMUIHGIMD-UHFFFAOYSA-H 0.000 description 1
- 235000010994 magnesium phosphates Nutrition 0.000 description 1
- QQFLQYOOQVLGTQ-UHFFFAOYSA-L magnesium;dihydrogen phosphate Chemical compound [Mg+2].OP(O)([O-])=O.OP(O)([O-])=O QQFLQYOOQVLGTQ-UHFFFAOYSA-L 0.000 description 1
- 229910001463 metal phosphate Inorganic materials 0.000 description 1
- 229910000401 monomagnesium phosphate Inorganic materials 0.000 description 1
- 235000019785 monomagnesium phosphate Nutrition 0.000 description 1
- 239000003973 paint Substances 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 235000011837 pasties Nutrition 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 239000011253 protective coating Substances 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- APSBXTVYXVQYAB-UHFFFAOYSA-M sodium docusate Chemical compound [Na+].CCCCC(CC)COC(=O)CC(S([O-])(=O)=O)C(=O)OCC(CC)CCCC APSBXTVYXVQYAB-UHFFFAOYSA-M 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 230000002195 synergetic effect Effects 0.000 description 1
- 239000004408 titanium dioxide Substances 0.000 description 1
- 231100000331 toxic Toxicity 0.000 description 1
- 230000002588 toxic effect Effects 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
- 239000010456 wollastonite Substances 0.000 description 1
- 229910052882 wollastonite Inorganic materials 0.000 description 1
- NDKWCCLKSWNDBG-UHFFFAOYSA-N zinc;dioxido(dioxo)chromium Chemical class [Zn+2].[O-][Cr]([O-])(=O)=O NDKWCCLKSWNDBG-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09C—TREATMENT OF INORGANIC MATERIALS, OTHER THAN FIBROUS FILLERS, TO ENHANCE THEIR PIGMENTING OR FILLING PROPERTIES ; PREPARATION OF CARBON BLACK ; PREPARATION OF INORGANIC MATERIALS WHICH ARE NO SINGLE CHEMICAL COMPOUNDS AND WHICH ARE MAINLY USED AS PIGMENTS OR FILLERS
- C09C1/00—Treatment of specific inorganic materials other than fibrous fillers; Preparation of carbon black
- C09C1/0081—Composite particulate pigments or fillers, i.e. containing at least two solid phases, except those consisting of coated particles of one compound
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
- C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
- C09D5/08—Anti-corrosive paints
- C09D5/082—Anti-corrosive paints characterised by the anti-corrosive pigment
- C09D5/084—Inorganic compounds
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Composite Materials (AREA)
- Inorganic Chemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Wood Science & Technology (AREA)
- Paints Or Removers (AREA)
- Pigments, Carbon Blacks, Or Wood Stains (AREA)
- Preventing Corrosion Or Incrustation Of Metals (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE:
This invention relates to a phosphate-based, corrosion inhibiting pigment consisting of 3 to 97 weight % of MgHPO4 ? 3H2O, the balance being CaHPO4 ? 2H2O. The pigment is used to avoid corrosion of iron and iron alloys and is employed in the form of a painting composition or paste. Up to 95 weight % of the pigment can be replaced by a pigment exten-der.
This invention relates to a phosphate-based, corrosion inhibiting pigment consisting of 3 to 97 weight % of MgHPO4 ? 3H2O, the balance being CaHPO4 ? 2H2O. The pigment is used to avoid corrosion of iron and iron alloys and is employed in the form of a painting composition or paste. Up to 95 weight % of the pigment can be replaced by a pigment exten-der.
Description
~1177~5 The present invention relates to a phosphate-based pig-ment inhibiting the corrosion of iron and iron alloy sur-faces.
It has long been known that painting or coating compo sitions which are based on a binder and contain metal phos-phate as a protective pigment can be applied to the surfaces of iron or iron alloy articles so as to avoid corrosion in contact with the atmosphere. A pigment based on calcium phosphate and zinc phosphate has been disclosed in British Patent Specification 915 512, and a pigment prepared from a mixture of calcium phosphate and zinc oxide has been dis-closed in British Patent Specification 990 167.
Further corrosion-inhibiting pigments which are based on magnesium phosphates, and more especially on trimagnesium orthosphosphate, have been described in &erman Patent Spe-cification "Offenlegungsschrift" 24 58 706.
A still further corrosion-inhibiting pigment based on acid magnesium phosphate which may be used in admixture with an aluminum paste has been described in Patent Specification (~erman Democratic Republic) 114 423.
Nontoxic corrosion-inhibiting pigments which are based on phosphates are, howe~er, unable to produce the good corrosion-inhibiting effects typical of toxic pigments, such as red lead or metal chromates, especially zinc chromates. These latter pigments are also unsatisfactory in respect of the following points: Pores are liable to be formed in the weld seams of sur~ace-treated ~ron or iron alloy art~cles. In addition to this, grinding and welding operations are liable lil77~5 to entail conversion of the lead and al~o of the chromate , .
compounds to dusty material so that it is obligatory for these compounds to be processed with the use of dust-ex-hausting means, for medicinal reasons.
Stil further, anhydrous pigments do not necessarily en-sure the low electric resistance which is so important in modern spot welding.
It is therefore an ob~ect of the present invention to providè a nontoxic h~ghly efficient corrosion-inhibiting pigment which is easy to apply as a protective coating to the surfaces of iron or iron alloy articles and does not adversely affect welding operations.
In accordance with our present invention, we have unexpec-tedly found that the corrosion-inhibiting effect produced ~n-dividually by dicalc~um phosphate and dimagnesium phosphatecan be synergetically improved by the use of a mixture of secondary phosphates of calcium and magneRium as a corrosion inhibiting pigment. This synergetic effect remains substan-tially unaffected by the mixing ratio, whic ~ ay vary within wide limits, selected for preparing the above mixture of secondary dicalcium and dimagnesium phosphates containing water of crystallization. Even a mixture composed of 3 to 97 weight % of CaHP04 2H20, the balance being Mg~P04 3H20, produces the above ~ynergetic effect.
Pigment compositions of 5 to 35 weight % of MgHP04 3H20, the balance being CaHP04 2~20, have especially good corro-sion-inhibiting properties.
Up to 95 weight % of the pigment can be replaced by sui-table fillers or extenders substantially in the absence of il~77~5 any significant adverse effect on the corrosion-inhibiting properties of the pigment. Useful pigment filler materials comprise e.g. barites, talc, alXaline earth metal carbonates or wollastonite. It has also been found that the present cor-rosion-inhibiting pigments have no inherent coloration which would adversely affect the coloration of the compositions ma-de therefrom.
The present invention relates more particularly to corro-sion-inhibiting pigments comprising a mixture of dicalcium phosphate and dimagnesium phosphate, the individual pigment particles being superficially fixed by means of a suitable binder, such as a drying oil, self-hardening resin or aqueous suspension dye.
The corrosion-inhibiting pigments of the present inven-tion can be used in painting compositions, such as in air-drying compositions or in baking lacquers, or in pasty for~
for the surface protection of iron and iron-alloy articles, the compositions or pastes being used in admixture with cu-stomary binders, solvents, fillers and color-improving agents.
These latter agents, regardless of whether they are added individually or collectively, do substantially not affect the corrosion inhibiting properties of the present pigments. Cu-stomary color-improving agents comprise, e.g. titanium dioxi-de as a turbid$ty inducing agent, asbestines or porcelaine clay for inhibiting the deposition of solid matter, antimony ox~de for inhibiting chalking, ethylmethylketox$me for inhi-biting ski.~ning, and diatomaceous earth for promotin~ the spreading out of the painting composition.
lli77~)S
It is preferable for the painting composition cr paste to contain the pigment in a concentration by volume (brief-ly termed PCV hereinafter) of 10 to 60, preferably 20 to 40 % by volume. The term "pigment concentration by volume"
as used herein denotes the percentage by volume of all pig-ments including pigment extender contained in the overall volume of the dried protecti~e layer.
The pigments of the present invention were applied to sheet metal specim ?nS and the specimens were sub~ected to the following short time tests: Salt Spray Test (ASTM B
117-64; briefly referred to as SST hereinafter); Condensed Moisture Test (DIN 50017; DIN-stands for German Industrial Standard; thls test is briefly referred to as CWT herein-after); Kesternich Test (DIN 50018; briefly referred to as KT hereinafter~ The specimens so tested were inspected for:
degreee of corrosion (rust) (European scale for determining the degree of corrosion of anticorrosive paints - obtainab-le upon request from Fédération Nationale des Industries des Peintures, Vernis, Encres d'imprimerieet Couleurs fines, 42.
AY. Marceau, 75008 Paris, France); degree of blister forma-tion (DIN 5~209); and corrosion of metal underlying pigment of cross-scratched specimen. The standardized magnitudes deflning the degree of corrosion and formation of blisters, and the corrosion depth (im millimeters) of the underlying metal were assigned an evaluation score (ES~ of 0 to 100.
More specifically, the score (decreasing from 100 to 0) assigned to the individual specimens was the lower the more serious the degree of corosion or blister formation or cor-rosion of the underlying metal. Each of the above three tests ill77;~5 provides for a maximum score of 300 ~o be assigned to a 100 ~ corrosion_proof specimen.
In order to identify the efficiency of the present cor-rosion-inhibiting pigment by a numerical value, the three evaluation scores (ES) were converted to a single characteri-stic value (CV). The salt spray test is the best to reveal the protective efficiency under long term outdoor conditions.
This is the reason why the factor 2 has been assigned to the salt spray test in calculating the characteristic value in accordance with the following formula:
CV = 2 ES (SST) ~ ES (CWT) + ES (KT) 100 As can be seen, a pigment affording a 100 ~ corrosion_proof effect can be assigned a maximum caracteristic value of 100.
The following Examples illustrate the invention:
EXAMPLE 1:
The following materials were homogenized in a mixer pro-vided with a stirrer; the parts being by weight Alkyd resin (ALFTALATE AF 342; this is a38.0 registered Trade Mark of HOECHST AG; Germany) Ethyl glycol 4.0 White spirlt 4,0 25 n-butanol ~,5 Antiskinning agent (A~ITOL XL 297; th~s is 0.5 a registered Trade Mar~ of HOECHST AG) 'l i~177~5 Dimethyl-dioctadecyl-ammonium montmorillonite 1.O
(Bentone 34; 10 % strength, a pro-B duct of Titangesellschaft, Germany) Talc 3.2 5 Barium Sulfate 4.6 Titanium dioxide (RN 59; a product of 4.8 Titangesellschaft) Slm CaHP04 2H20 ~ MgHP04-3H20 5.2 A corrosion-inhibiting composition wlth a PCV = 20 was made. The results obtained therewith are indicated in the Table hereinafter.
EXAMPLE 2:
The following materials were homogenized in a mixer pro-vided with a stirrer, the parts being by weight:
Alkyd resin (ALFTALATE AF 342) 38.0 Ethyl glycol 4.0 White spirit 4.0 n-butanol 0.5 Antiskinning agent (AD~ITOL XL 297) 0.5 20 Dimethyl-dioctadecyl-ammonium montmorillonite 1.O
(Bentone 34; 10 % strength) Talc 10.0 Barium sulfate 11.0 Titanium diox~de (RN 59) 13.0 Sum Ca~P04-2H20 + MgHP04 3H2 18.0 A corrosion-inhibit~ng composition with a PCV = 36 was made. The results cbtained therewith are indicated in the following Table.
* ~ rk 11177~5 EXAMPLE 3: (Comparative Example3 Example 1 was repeated save that a zinc phosphate pig-ment of the formula Zn3(P04)2 2H20 was substituted for CaHP04 2H20 and MgHP04 3H20.
A composition with a PCV = 36 was made. The result ob-talned therewith is indicated in the follGwing Table.
EXAMPLE 4: (Comparative Example) Example 1 was repeated save that a zinc oxide pigment was substituted for MgHP04 3H20. CaHP04 2H20 and zinc oxide were used in a mixing ratio of 75 : 25.
A composition with a PCV = 36 was made. The result ob-tained therewith is indicated in the following Table.
11177~5 ~ ~ , a~ 1~ 0 ~ CJ~ 0 J ~ S) ~ 1~ 0 0 a) ~
V ~ ~ ~
~q ~
C N . . , ~ ~ ~ ~ O O ~ U~O ~ ~ ~ l l a. .
. O
N
,~, bl~ o, __ ~__ .
~ ~.~ 11111111111~1ll 01 0 0~
~. .
. I ~ U~ O O O O O O O O O ~ ~ O
O ~ t~J ~ J u~ ~L) ~ 0 ~ ~ 0~ G
.~ ~:
~ o i~ ~
+~ O t~ O G O O O O O O O Lt~
~ 11~ OSJ~ __ P< V
It has long been known that painting or coating compo sitions which are based on a binder and contain metal phos-phate as a protective pigment can be applied to the surfaces of iron or iron alloy articles so as to avoid corrosion in contact with the atmosphere. A pigment based on calcium phosphate and zinc phosphate has been disclosed in British Patent Specification 915 512, and a pigment prepared from a mixture of calcium phosphate and zinc oxide has been dis-closed in British Patent Specification 990 167.
Further corrosion-inhibiting pigments which are based on magnesium phosphates, and more especially on trimagnesium orthosphosphate, have been described in &erman Patent Spe-cification "Offenlegungsschrift" 24 58 706.
A still further corrosion-inhibiting pigment based on acid magnesium phosphate which may be used in admixture with an aluminum paste has been described in Patent Specification (~erman Democratic Republic) 114 423.
Nontoxic corrosion-inhibiting pigments which are based on phosphates are, howe~er, unable to produce the good corrosion-inhibiting effects typical of toxic pigments, such as red lead or metal chromates, especially zinc chromates. These latter pigments are also unsatisfactory in respect of the following points: Pores are liable to be formed in the weld seams of sur~ace-treated ~ron or iron alloy art~cles. In addition to this, grinding and welding operations are liable lil77~5 to entail conversion of the lead and al~o of the chromate , .
compounds to dusty material so that it is obligatory for these compounds to be processed with the use of dust-ex-hausting means, for medicinal reasons.
Stil further, anhydrous pigments do not necessarily en-sure the low electric resistance which is so important in modern spot welding.
It is therefore an ob~ect of the present invention to providè a nontoxic h~ghly efficient corrosion-inhibiting pigment which is easy to apply as a protective coating to the surfaces of iron or iron alloy articles and does not adversely affect welding operations.
In accordance with our present invention, we have unexpec-tedly found that the corrosion-inhibiting effect produced ~n-dividually by dicalc~um phosphate and dimagnesium phosphatecan be synergetically improved by the use of a mixture of secondary phosphates of calcium and magneRium as a corrosion inhibiting pigment. This synergetic effect remains substan-tially unaffected by the mixing ratio, whic ~ ay vary within wide limits, selected for preparing the above mixture of secondary dicalcium and dimagnesium phosphates containing water of crystallization. Even a mixture composed of 3 to 97 weight % of CaHP04 2H20, the balance being Mg~P04 3H20, produces the above ~ynergetic effect.
Pigment compositions of 5 to 35 weight % of MgHP04 3H20, the balance being CaHP04 2~20, have especially good corro-sion-inhibiting properties.
Up to 95 weight % of the pigment can be replaced by sui-table fillers or extenders substantially in the absence of il~77~5 any significant adverse effect on the corrosion-inhibiting properties of the pigment. Useful pigment filler materials comprise e.g. barites, talc, alXaline earth metal carbonates or wollastonite. It has also been found that the present cor-rosion-inhibiting pigments have no inherent coloration which would adversely affect the coloration of the compositions ma-de therefrom.
The present invention relates more particularly to corro-sion-inhibiting pigments comprising a mixture of dicalcium phosphate and dimagnesium phosphate, the individual pigment particles being superficially fixed by means of a suitable binder, such as a drying oil, self-hardening resin or aqueous suspension dye.
The corrosion-inhibiting pigments of the present inven-tion can be used in painting compositions, such as in air-drying compositions or in baking lacquers, or in pasty for~
for the surface protection of iron and iron-alloy articles, the compositions or pastes being used in admixture with cu-stomary binders, solvents, fillers and color-improving agents.
These latter agents, regardless of whether they are added individually or collectively, do substantially not affect the corrosion inhibiting properties of the present pigments. Cu-stomary color-improving agents comprise, e.g. titanium dioxi-de as a turbid$ty inducing agent, asbestines or porcelaine clay for inhibiting the deposition of solid matter, antimony ox~de for inhibiting chalking, ethylmethylketox$me for inhi-biting ski.~ning, and diatomaceous earth for promotin~ the spreading out of the painting composition.
lli77~)S
It is preferable for the painting composition cr paste to contain the pigment in a concentration by volume (brief-ly termed PCV hereinafter) of 10 to 60, preferably 20 to 40 % by volume. The term "pigment concentration by volume"
as used herein denotes the percentage by volume of all pig-ments including pigment extender contained in the overall volume of the dried protecti~e layer.
The pigments of the present invention were applied to sheet metal specim ?nS and the specimens were sub~ected to the following short time tests: Salt Spray Test (ASTM B
117-64; briefly referred to as SST hereinafter); Condensed Moisture Test (DIN 50017; DIN-stands for German Industrial Standard; thls test is briefly referred to as CWT herein-after); Kesternich Test (DIN 50018; briefly referred to as KT hereinafter~ The specimens so tested were inspected for:
degreee of corrosion (rust) (European scale for determining the degree of corrosion of anticorrosive paints - obtainab-le upon request from Fédération Nationale des Industries des Peintures, Vernis, Encres d'imprimerieet Couleurs fines, 42.
AY. Marceau, 75008 Paris, France); degree of blister forma-tion (DIN 5~209); and corrosion of metal underlying pigment of cross-scratched specimen. The standardized magnitudes deflning the degree of corrosion and formation of blisters, and the corrosion depth (im millimeters) of the underlying metal were assigned an evaluation score (ES~ of 0 to 100.
More specifically, the score (decreasing from 100 to 0) assigned to the individual specimens was the lower the more serious the degree of corosion or blister formation or cor-rosion of the underlying metal. Each of the above three tests ill77;~5 provides for a maximum score of 300 ~o be assigned to a 100 ~ corrosion_proof specimen.
In order to identify the efficiency of the present cor-rosion-inhibiting pigment by a numerical value, the three evaluation scores (ES) were converted to a single characteri-stic value (CV). The salt spray test is the best to reveal the protective efficiency under long term outdoor conditions.
This is the reason why the factor 2 has been assigned to the salt spray test in calculating the characteristic value in accordance with the following formula:
CV = 2 ES (SST) ~ ES (CWT) + ES (KT) 100 As can be seen, a pigment affording a 100 ~ corrosion_proof effect can be assigned a maximum caracteristic value of 100.
The following Examples illustrate the invention:
EXAMPLE 1:
The following materials were homogenized in a mixer pro-vided with a stirrer; the parts being by weight Alkyd resin (ALFTALATE AF 342; this is a38.0 registered Trade Mark of HOECHST AG; Germany) Ethyl glycol 4.0 White spirlt 4,0 25 n-butanol ~,5 Antiskinning agent (A~ITOL XL 297; th~s is 0.5 a registered Trade Mar~ of HOECHST AG) 'l i~177~5 Dimethyl-dioctadecyl-ammonium montmorillonite 1.O
(Bentone 34; 10 % strength, a pro-B duct of Titangesellschaft, Germany) Talc 3.2 5 Barium Sulfate 4.6 Titanium dioxide (RN 59; a product of 4.8 Titangesellschaft) Slm CaHP04 2H20 ~ MgHP04-3H20 5.2 A corrosion-inhibiting composition wlth a PCV = 20 was made. The results obtained therewith are indicated in the Table hereinafter.
EXAMPLE 2:
The following materials were homogenized in a mixer pro-vided with a stirrer, the parts being by weight:
Alkyd resin (ALFTALATE AF 342) 38.0 Ethyl glycol 4.0 White spirit 4.0 n-butanol 0.5 Antiskinning agent (AD~ITOL XL 297) 0.5 20 Dimethyl-dioctadecyl-ammonium montmorillonite 1.O
(Bentone 34; 10 % strength) Talc 10.0 Barium sulfate 11.0 Titanium diox~de (RN 59) 13.0 Sum Ca~P04-2H20 + MgHP04 3H2 18.0 A corrosion-inhibit~ng composition with a PCV = 36 was made. The results cbtained therewith are indicated in the following Table.
* ~ rk 11177~5 EXAMPLE 3: (Comparative Example3 Example 1 was repeated save that a zinc phosphate pig-ment of the formula Zn3(P04)2 2H20 was substituted for CaHP04 2H20 and MgHP04 3H20.
A composition with a PCV = 36 was made. The result ob-talned therewith is indicated in the follGwing Table.
EXAMPLE 4: (Comparative Example) Example 1 was repeated save that a zinc oxide pigment was substituted for MgHP04 3H20. CaHP04 2H20 and zinc oxide were used in a mixing ratio of 75 : 25.
A composition with a PCV = 36 was made. The result ob-tained therewith is indicated in the following Table.
11177~5 ~ ~ , a~ 1~ 0 ~ CJ~ 0 J ~ S) ~ 1~ 0 0 a) ~
V ~ ~ ~
~q ~
C N . . , ~ ~ ~ ~ O O ~ U~O ~ ~ ~ l l a. .
. O
N
,~, bl~ o, __ ~__ .
~ ~.~ 11111111111~1ll 01 0 0~
~. .
. I ~ U~ O O O O O O O O O ~ ~ O
O ~ t~J ~ J u~ ~L) ~ 0 ~ ~ 0~ G
.~ ~:
~ o i~ ~
+~ O t~ O G O O O O O O O Lt~
~ 11~ OSJ~ __ P< V
Claims (3)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. Phosphate-based pigment inhibiting the corrosion of iron and iron alloy surfaces comprising a mixture of secondary phosphates of calcium and magnesium as the corrosion-inhibiting pigment.
2. Corrosion-inhibiting pigment as claimed in claim 1, comprising the compounds Ca H PO4 ? 2 H2O and Mg H PO4 ? 3 H2O.
3. Corrosion-inhibiting pigment as claimed in claim 1, comprising 3 to 97 weight % of MgHPO4 ? 3H2O, the balance being CaHPO4 ? 2H2O.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP2849712.3 | 1978-11-16 | ||
| DE19782849712 DE2849712A1 (en) | 1978-11-16 | 1978-11-16 | CORROSION-INHIBITING PIGMENT ON PHOSPHATE-BASED |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1117705A true CA1117705A (en) | 1982-02-09 |
Family
ID=6054825
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000339536A Expired CA1117705A (en) | 1978-11-16 | 1979-11-09 | Corrosion-inhibiting pigment based on phosphate |
Country Status (6)
| Country | Link |
|---|---|
| EP (1) | EP0011223B1 (en) |
| JP (1) | JPS5571759A (en) |
| AT (1) | ATE924T1 (en) |
| CA (1) | CA1117705A (en) |
| DE (2) | DE2849712A1 (en) |
| NO (1) | NO155248C (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5126074A (en) * | 1987-09-21 | 1992-06-30 | Dr. Hans Heubach Gmbh & Co. Kg | Anti corrosive pigments based on alkaline earth hydrogen phosphates |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2951126A1 (en) * | 1979-12-19 | 1981-06-25 | Hoechst Ag, 6230 Frankfurt | METHOD FOR PRODUCING FINE DISPERSIBLE, SLIGHTLY SOLUBLE SALTS OF OXYGEN ACIDS OF PHOSPHORUS |
| US4740393A (en) * | 1985-07-10 | 1988-04-26 | Nl Chemicals, Inc. | Coating composition containing a calcium phosphite and process for protecting a surface from corrosion |
| NO312911B1 (en) | 1994-12-22 | 2002-07-15 | Budenheim Rud A Oetker Chemie | Anti-corrosion pigment and its use |
| RU2151157C1 (en) * | 1999-07-19 | 2000-06-20 | Общество с ограниченной ответственностью "Производственное предприятие "Ярпромцентр" | Anticorrosive pigment |
| PL2222793T3 (en) | 2007-11-19 | 2018-03-30 | Grace Gmbh & Co. Kg | Anti-corrosive particles |
| AR074508A1 (en) | 2008-12-08 | 2011-01-19 | Grace Gmbh & Co Kg | ANTI-CORROSIVE PARTICLES |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB904861A (en) * | 1958-07-01 | 1962-08-29 | Goodlass Wall & Co Ltd | New or improved coating compositions |
| GB915512A (en) * | 1958-07-01 | 1963-01-16 | Goodlass Wall & Co Ltd | New or improved coating compositions |
| DE977737C (en) * | 1959-06-19 | 1969-03-27 | Eltro Gmbh | Infrared camouflage paint |
| DE977735C (en) * | 1960-07-08 | 1969-03-27 | Eltro Gmbh | Process for the production of inorganic pigments for IR camouflage paints |
| US3445259A (en) * | 1968-05-03 | 1969-05-20 | Grace W R & Co | Coprecipitated cahpo4-2h2o and caso4-2h2/ pigment and method of preparation |
| GB1536660A (en) * | 1974-12-20 | 1978-12-20 | Albright & Wilson | Coating compositions |
-
1978
- 1978-11-16 DE DE19782849712 patent/DE2849712A1/en not_active Withdrawn
-
1979
- 1979-11-07 AT AT79104351T patent/ATE924T1/en not_active IP Right Cessation
- 1979-11-07 EP EP79104351A patent/EP0011223B1/en not_active Expired
- 1979-11-07 DE DE7979104351T patent/DE2962645D1/en not_active Expired
- 1979-11-09 CA CA000339536A patent/CA1117705A/en not_active Expired
- 1979-11-15 NO NO793697A patent/NO155248C/en unknown
- 1979-11-16 JP JP14785679A patent/JPS5571759A/en active Granted
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5126074A (en) * | 1987-09-21 | 1992-06-30 | Dr. Hans Heubach Gmbh & Co. Kg | Anti corrosive pigments based on alkaline earth hydrogen phosphates |
Also Published As
| Publication number | Publication date |
|---|---|
| EP0011223A1 (en) | 1980-05-28 |
| JPS5571759A (en) | 1980-05-30 |
| DE2849712A1 (en) | 1980-05-29 |
| DE2962645D1 (en) | 1982-06-09 |
| NO793697L (en) | 1980-05-19 |
| JPS6324026B2 (en) | 1988-05-19 |
| EP0011223B1 (en) | 1982-04-28 |
| NO155248C (en) | 1987-03-04 |
| NO155248B (en) | 1986-11-24 |
| ATE924T1 (en) | 1982-05-15 |
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