Classifications

• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
  • C23F11/00—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent
  • C23F11/08—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent in other liquids
  • C23F11/10—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent in other liquids using organic inhibitors
  • C23F11/173—Macromolecular compounds
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G75/00—Macromolecular compounds obtained by reactions forming a linkage containing sulfur with or without nitrogen, oxygen, or carbon in the main chain of the macromolecule
  • C08G75/20—Polysulfones
  • C08G75/205—Copolymers of sulfur dioxide with unsaturated organic compounds
  • C08G75/22—Copolymers of sulfur dioxide with unsaturated aliphatic compounds

Definitions

• ABSTRACT A metal corrosion inhibitor consisting of a polysulfone compound obtained by copolymerizing or interpolymerizing sulfur dioxide and at least one 1,6-diene compound.
• the above metal corrosion inhibitor may be added in a corrosion-inhibitorily effective amount, preferably at least 1 ppm., to a corrosive medium, with which a metal comes into contact, to inhibit the medium from corroding the metal.
• This invention relates to a corrosion inhibitor 'for metals in water, aqueous solutions of salts or aqueous solutions of inorganic or organicacids, and to a method for inhibiting the corrosion of the metals with said inhibitor.
• This invention provides a metal corrosion inhibitor represented by the general formula: v
• M is at least one member selected from the.
• X is Cl, Br, I, CH COO, H PO i in which Y is CH or O; and X is the same as defined regarding formula (1),
• R is hydrogen, a straight or branched chain alkyl having 1 to 12 carbon atoms, hydroxymethyl, 2- hydroxyethyl, 3-hydroxypropyl, 4-hydroxybutyl, NH chloromethyl or a group represented by formula (III- A):
• R, R and R which may be the same or different, are hydrogen, straight or branched chain alkyls having 1 to 12 carbon atoms, aralkyls having 7 to 9 carbon atoms or Z-hydroxyethyl, including the case where and the case where means r N3, NQ, NQ or NQ 5 COOH CONHZ and X is the same as defined regarding the formula (I),
• R is hydrogen, a straight or branched chain alkyl having 1 to 18 carbon atoms, an aralkyl having 7 to carbon atoms, 2-hydroxyethyl, allyl or propargyl; and X is the same as defined regarding the formula (1),
• the metal corrosion inhibitor of this invention is a polysulfone obtained by copolymerizing or interpolymerizing sulfur dioxide and at least one compound selected from the group consisting of compounds represented by the following formulas (A) (H):
• the compounds represented by the general formulas (A) to (H) are all 1,6-diene type unsaturated compounds and generally, these are easily copolymerized with sulfur dioxide to produce polysulfones which are 1 z 1 cyclocopolymers.
• a number of these polysulfones have been disclosed by the inventors. (Refer to Japanese Pat. Publication No. 14587/66; US. Pat. No. 3,375,233 and 3,585,118; British Pat. Nos. 1,098,500 and 1,275,157; and Preprint IV at the 26th Annual Meeting of the Japan Chemical Society, P. 1820 (1972)).
• the sulfur dioxide component be contained in a molar fraction of at least 0. l.
• the amount of the 'sulfur dioxide component is smaller, there is substantially no difference in corrosion-inhibiting effect between such a polysulfone compound and a polymer free from the sulfur dioxide component.
• the maximum amount of the sulfur dioxide component is a molar fraction of 0.5
• the preferable amount is a molar fraction of 0.3 to 0.5
• the most preferable amount is a molar fraction of 0,5.
• the term molar fraction used herein refers to an average value, and hence, each single molecule may contain the sulfur dioxide component in an amount outside the above-mentioned range.
• sulfur dioxide is very easily copolymerized with at least one monomer having formulas (A) to (H) corresponding to the M component of the above general formula, and the sulfur dioxide and the above monomer or monomers are falternately bonded to each other to form an alternating copolymer as mentioned above.
• the above monomer or monomers (A) to (H) are used in excess of sulfur dioxide in the copolymerization, it is considered that an alternating copolymer or interpolymer in which the M component, i.e.
• the corrosion inhibitor of this invention is a mixture of these polymers.
• Causes of corrosion of metals in an aqueous solution vary depending upon the kind of the solution, namely, the kind of substances dissolved therein, temperature and the kind of the metals.
• the main causes of corrosion of metals in industrial water are' considered to be the oxygen and carbon dioxide dissolved in water, and in the case of pickling solutions, corrosion is, of course, caused by acids.
• Effective corrosion inhibitors aredetermined depending upon the kinds of substances which cause corrosion, and even if the substances which cause corrosion are the same, effective inhibitors also vary when the temperature used is different.
• inhibitors to be added to pickling baths must meet various requirements, e.g., they should not .lower the speed'of removal of scales, they must result in a beautiful finished surface and they must have an excellent solubility and stability in the bath. In view of these requirements, the corrosion inhibitors must be tailor made.
• the polysulfones used in this invention are high molecular weight compounds (corresponding to intrinsic viscosities of 0.01 to 2.0 dl/g as measured in N/lO NaCl solution at 30C). (Conventionally, some of high molecular weight compounds have been used and it has been known that the high molecular weight compounds, even when used in an extremely smaller amount than low molecular weight compounds containing the same functional groups as those of said high molecular weight compounds, can exhibit the same corrosion inhibiting effect as the low molecular weight compounds.)
• the polysulfone compounds used in this invention include a great number of compounds which have a common basic. skeleton, but have different side chains. Moreover, any two or more compounds represented by the general formulas (I) to (V) may be copolymerized with sulfur dioxide into interpolymers, and hence, such inhibitors as having different two or more functional groups in one molecule are obtained. Therefore, suitable polysulfones may be chosen depending upon corrosion environment.
• the polysulfone compounds are exceedingly stable in acids. Therefore, the corrosion inhibiting effect can be maintained for a long period of time when the compounds are used in acids, e.g., in the pickling of steel.
• the polysulfone compound of this invention per se can act as a metal corrosion inhibitor, and therefore, it is generally added alone to a corrosive medium. However, it may be added along with an anticorrosive or synergistic agent which is known in the art, such as alkali halides, low molecular weight organic amine compounds and acetylene alcohol.
• the amount of the polysulfone compounds added to a corrosion bath varies depending upon the kind of the compounds and corrosion environment, but generally, they may be used in an extremely low concentration.
• the addition in an-amount of 1 ppm. to a corrosion bath can attain a considerable corrosion inhibiting effect, but usually they are used in a concentration higher than 5 ppm.
• polysulfone compounds used in this invention include a great number of compounds, and the representatives thereof are as follows, and the corrosion inhibiting effects of thirty of these compounds will be specifically explained in the Examples given hereinafter:
• polysulfone compounds having the above struc- EXAMPLE tures l) to (30) can be prepared by the method already disclosed by the inventors (Sec Japanese PaL This example illustrates the effect ot the corrosion Publications No 4587/66 and Na 3 1842/7]; Us 55 inhibitors of this invention against corrosion of a mild Pat. No. 3,375,233 and 3,585,118; British Pat. Nos. 5M1 P in city wuwr- 1993500 and 1 275 57 and p [V at the 26th Standstill tests were carried out for 100 hours at Annual Meeting of the Japan Chemical Society, p.
• EXAMPLE 2 The same test panel as in Example 1 was subjected to The same test panel as in Example 1 was subjected to corrosion treatment in city water under agitation at corrosion treatment in .110 hydrochloric acid at 20C about C for 100 hours. The results are shown in for 100 hours. The results are shown in Table 3.
• Test panel Polished mild steel plate (5. GJI-ll-SPCCB X 20 X 1 mm). Corrosive liquid: City water Amount of liquid: 5 cc per cm of the steel plate Treatment: At 50C 2C for hours with agitation Table 3 Compara- Compara- Corrosion tive tive Polyinhibitors inhibitor inhibitor sulfone d l Concentra- I I tion l0 l0 2 l0 5 l0 *l0 5 a l0 l0 l0 5 (p Corrosion r inhibitor 82.4 2 5 91.5 92.6,: 90.4 92.4 94.5 98.4 99.1 96.2 93.5 98.4 efficiency Corrosion Polyinhibitors sulfone Concentration 5 l0 l0 l0 5 2 5 5 5 5 5 5 2 (ppm) Corrosion inhibitor 98.4 90.6 94.5 98.2 94.5 93.5 94.4 92.8 93.9 96.4 95.8 efficiency i *Comparative inhibitor (A) was
• Comparative inhibitor (B) was dodecyltrimethylammonium chloride.
• Test panel Polished mild steel plate (JIS. G3l4l-SPCCB, 80 X 20 X 1 mm).
• Corrosive liquid 10 71 hydrochloric acid.
• Amount of liquid 5 cc per cm of the steel plate.
• Test panel The same test panel as in Table 3. Corrosive liquid: ll) /1 hydrochloric acid. Amount of liquid: 5 cc per mm of the steel plate. Treatment: At C for 2 hours.
• Example 5 The same test panel as in Example'l was subjected to corrosion treatment in 10 sulfuric acid at 20C for 100 hours to examine the corrosion inhibiting effect of 25 sulfuric acid 5 ferrous ion (added as ferrous sulfate) at 98 i 1Cfor 3 minutes.
• Amount of liquid 350 g of the acid per 2 test panels.
• a method for inhibiting the corrosion of a metal which comprises adding to a corrosive medium with which the metal comes into contact a corrosioninhibitorily effective amount of a metal corrosion inhibitor represented by the general formula II I S M ](L a l a wherein M is one member selected from the group consisting of methyl. carboxyethyl. cyanomethyl. 2-cyanoethyl. 2- sulfoethyl. sulfopropyl. Z-hydroxyethyl, 3-chloro-2- hydroxypropyl. allyl propargyl or aor B-naphthomethyl; and X is Cl.
• X is the same as defined above and Y is CH; or O: a is an average molar fraction of the S0 component in the general formula and ranges from 0.1 to 0.5; and n is a degree of polymerization.
• corrosive medium is water. an aqueous salt solution or an inorganic or organic acid.
• corrosion inhibitor is added in an amount of at least 5 ppm to the corrosive medium.
• a method according to claim 5, wherein the corrosive medium is water, an aqueous Salt solution or an inorganic or organic acid.

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Citations (10)

• 1972
  • 1972-07-26 JP JP7474772A patent/JPS5310539B2/ja not_active Expired
• 1973
  • 1973-01-24 US US326290A patent/US3920392A/en not_active Expired - Lifetime
  • 1973-01-26 GB GB410773A patent/GB1381432A/en not_active Expired
  • 1973-01-26 CA CA162,220A patent/CA1001796A/en not_active Expired

Patent Citations (10)

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