Calcium tripolyphosphate: An anticorrosive pigment for paint

The objective of this work was to evaluate the performance of calcium tripolyphosphate in anticorrosive paints. Its anticorrosive properties were studied in pigment suspensions and in solventborne paints with 10% and 30% of the pigment by volume and a pigment volume concentration/critical pigment volume concentration (PVC/CPVC) equal to 0.8. The behavior of paints formulated with epoxy and alkyd resins was assessed by accelerated (salt spray cabinet and humidity chamber) and electrochemical tests (corrosion potential, ionic resistance, and polarization resistance). Calcium tripolyphosphate was proven to inhibit steel corrosion when incorporated in a paint film. Good protection was achieved employing only 10% by volume of the pigment, instead of 30%, as was suggested in the case of phosphates. The anticorrosion protection afforded by alkyd paints was impaired when the pigment content was increased. Epoxy paints seemed to be less sensitive to the pigment content. Centro de Investigación y Desarrollo en Tecnología de Pinturas (CIC-CONICET), Calle 52 e/121 y 122. (1900) La Plata. Argentina. Fax: 54.221.427. 1537. email: cidepint@ba.net     

Zinc hypophosphite: a suitable additive for anticorrosive paints to promote pigments synergism

In this investigation, the synergism promoted by zinc hypophosphite in an anticorrosive pigment mixture is reported. This paper describes the anticorrosive behavior of a commercial pigment mixture containing zinc hypophosphite, reduced levels of zinc phosphate, and zinc oxide. The anticorrosive performance of the pigment mixture was assessed by electrochemical techniques (corrosion potential and linear polarization measurements) employing pigment suspensions. The behavior of each separate component of the mixture was also studied in the same way. The nature of the protective layer was investigated by scanning electron microscopy (SEM). In a second stage, the anticorrosive properties of the pigment were assessed by incorporating it into alkyd and epoxy paints that were evaluated by accelerated (salt spray and humidity tests) and electrochemical measurements. Experimental results showed that improved anticorrosion protection is achieved in paints with reduced zinc phosphate contents as a consequence of the synergistic interaction between zinc hypophosphite and the other components of the pigment mixture.     

防腐蚀颜料有效成分三聚磷酸铝含量测定的研究

建立了离子交换柱色谱法分离测定防腐蚀颜料添加剂三聚磷酸铝含量的方法.适宜条件:选用氯化钾溶液作为淋洗液,加入pH为4.4的乙酸-乙酸钠缓冲溶液,控制淋洗液流速为4.5～5.0 mL/min,用浓度分别为0.15,0.25,0.50,0.75 mol/L的氯化钾溶液进行梯度淋洗.在优选条件下,成功分离了三聚磷酸铝样品中不同形态的磷酸盐(正磷酸盐、焦磷酸盐、三聚磷酸盐和三偏磷酸盐),并对各组分含量进行了测定.实验结果表明:离子交换柱分离法具有操作简便、器材价格低廉、准确度高等优点.     

Eco-friendly zero VOC anticorrosive paints for steel protection

With the growth of the green movement, it is important to prepare environmentally friendly anticorrosive paints to save lot of money, which are lost each year because of corrosion. High molecular weight organic corrosion inhibitor (safe adduct), barrier anticorrosive pigment (safe) and convertible anticorrosive pigment (toxic) are protective elements in paint formulations. Emulsification of the prepared adduct was the way to be applicable in water-borne paints, using mixture of emulsifiers. Surface tension measurements using ring method technique and thermal stability test could characterize the prepared emulsion systems. It was interesting to study the performance of the protective elements in water paint formulations based on short oil water thinned alkyd. Physical and mechanical properties of dry paint films, corrosion tests of the coated steel, water up-take% of the prepared paints, weight loss of steel under paint films after immersion in artificial sea water and corrosion inhibition efficiency of the protective elements were determined. Comparative studies of the protective elements in water-borne paints have been done according to performance, economic feasibility and environmental safety. It was found that zinc chromate as carcinogenic anticorrosive pigment could be replaced by 0.09% of the prepared water-borne corrosion inhibitor (MTDT adduct), 20% micaceous iron oxide (MIO) or their blend. Superior corrosion inhibition efficiency of steel was obtained in case of using MTDT/MIO blend. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

水性防腐蚀涂料的配方制定

An introduction to the formulation of aqucous anticorrosive coatings.     

导电防腐环氧涂料的制备

研究了不同树脂、溶剂、导电填料和烘干温度对导电防腐涂层性能的影响,确定了制备环氧导电防腐涂料的较佳工艺条件:改性环氧树脂25%(质量分数,下同),固化剂5%,银包玻璃微珠70%(银含量30%),溶剂为正丁醇和二甲苯的混合溶液,烘干温度60℃,烘干时间2 h.由此工艺得到的环氧导电防腐涂层呈乳白色,涂膜光滑,电阻率为0.03～0.05Ω.cm,附着力2级.经过25～30d的腐蚀试验,涂膜的电阻率变化较小.该环氧导电防腐涂料可用于电解行业,以减缓酸雾对金属导电材料的腐蚀.     

Evaluation of eco-friendly anticorrosive pigments for paints in service conditions

The performance of different replacements for chromates was studied. The anticorrosive properties of seven phosphate-based pigments, a calcium-exchange silica and a ferrite were assessed by electrochemical techniques and formulating solvent-borne paints with epoxy and alkyd resins. Paints contained 30% by volume of anticorrosive pigment, with respect to the total pigment content.     

A new pigment for smart anticorrosive coatings

The purpose of this paper was to evaluate the performance of a modified zeolite as an anticorrosive pigment for paints. A procedure to prepare the pigment was outlined and its anticorrosive properties assessed following the electrochemical behavior of a steel electrode in pigment suspension. In a second stage, alkyd paints were formulated employing different anticorrosive pigments: (1) 30% by volume (v/v) of the modified zeolitic rock, (2) 10% (v/v) of zinc phosphate, and (3) a mixture of 10% (v/v) zinc phosphate plus 20% (v/v) of the modified zeolitic rock. In every case, percentages were referred to the total pigment content. Titanium dioxide, zinc oxide, and barium sulfate were incorporated to complete the pigment formula. The pigment volume concentration/critical pigment volume concentration (PVC/CPVC) ratio was 0.8. The performance of the resulting anticorrosive paints was assessed by accelerated (salt spray and humidity chambers) tests and electrochemical (corrosion potential, ionic resistance, and polarization resistance) essays. It was demonstrated that the modified zeolite is effective in protecting steel from corrosion when it is used in combination with zinc phosphate. There exists a synergism between the modified zeolite and zinc phosphate that allows the zinc phosphate content in anticorrosive paints to be reduced.     

High performance water-based paints with non-toxic anticorrosive pigments

Legal restrictions have impelled the replacement of solvent-borne resins and of toxic chromates and lead-bearing pigments in the elaboration of paints. Water-based anticorrosive paints have come a long way to improve their efficiency but their behaviour is said to be poorer than that of solvent-based paints. Nevertheless, recent advances in water-borne technologies have now resulted in improved resin systems that may be employed to produce heavy-duty coatings.

The objective of this paper is to formulate high performance water-borne paints pigmented with non-toxic phosphate inhibitors. The anticorrosive properties of the paints were evaluated by accelerated tests (salt spray and humidity cabinets) and electrochemical tests (electrochemical impedance spectroscopy, EIS). The anticorrosive properties of the pigments were also evaluated by electrochemical tests.

It was found that it is possible to formulate high performance anticorrosive paints by selecting adequate water-borne resins and ecological pigments.     

磷酸锌防锈颜料低成本工艺的探索

采用氨 -碳铵溶液净化低度氧化锌生产磷酸锌的新工艺 ,克服了直接法固 -液反应的弊病 ,较明显地降低了原料成本。     

Ceramic microspheres to improve anticorrosive performance of phosphate paints

Zinc phosphate and related compounds have been proposed as “green” replacements for traditional anticorrosive pigments such as zinc chromate and lead oxides. However, environmental concerns have risen in the last years because the disposal of these materials in the environment increased phosphate levels in water and produce eutrophication of water bodies. The present paper deals with the possible incorporation of ceramic microspheres in alkyd paints in order to diminish phosphate content. The results suggested that paints with low phosphate content can be successfully formulated with a suitable selection of the amount and type of microspheres.     

Novel anticorrosive emulsion-type paints containing organic/inorganic nanohybrid particles

Novel anticorrosive emulsion-type paints were prepared by utilizing organic/inorganic nanohybrid particles (nHPs) of composition (1:1) based on polyaniline (PANI) and nanosilica. Polyaniline (PANI) and nanosilica were synthesized via chemical oxidative and sol–gel polymerization techniques respectively. The prepared materials were characterized via (gel permeation chromatography (GPC), infra red (FT-IR), transmission electron microscope (TEM) and differential scanning calorimetry (DSC)). The binder used in this context is polyvinyl acetate (PVAc). Nanohybrid particles/PVAc emulsion composites (nHPs ECs) were simply formed by individual mixing of the prepared neat PANI and nHPs of composition (1:1) with PVAc to produce the corresponding nanohybrid particles/PVAc emulsion composites EC₁ and EC₂ respectively. The chemical and basic properties including (acid and alkali resistance, adhesion, washability, gloss, opacity, whiteness, hardness, impact, and weathering) as well as the anticorrosion properties of the blank paint films and the paint films containing neat PANI and nHPs of different concentrations (5%, 10%, and 15%) were investigated and evaluated. The obtained experimental results revealed that the presence of nHPs in the blank paint are highly enhanced both basic and anticorrosion properties of the coated films.     

Ion-exchange pigments in primer paints for anticorrosive protection of steel in atmospheric service: Cation-exchange pigments

Hexavalent chromium compounds (chromates) have been widely used as inhibitor pigments in the formulation of anticorrosive primers. However, their high toxicity and carcinogenic effects are forcing the development of effective chromate-free organic coatings. One such alternative is the use of ion-exchangeable pigments. Studies of these pigments have not been conclusive about their anticorrosive efficiency and controversy surrounds their functional mechanisms, exchange capacity and anticorrosive performance.     

高性能防锈颜料三聚磷酸铝

介绍了三聚磷酸铝的化学特性、开发历程、用作防锈颜料的优势、技术指标,在涂料中的使用量及在其他领域的应用,表明其作为一种无公害防锈颜料,应用前景良好。     

Evaluation of an environmentally friendly anticorrosive pigment for alkyd primer

An alkyd formulation containing zinc phosphate (10 wt.%) was prepared and subsequently modified replacing the latter anticorrosive additive by a very low concentration of conducting polymer. Specifically, three modified paints, which contain polyaniline emeraldine base (undoped form), polyaniline emeraldine salt (doped form) and an eco-friendly polythiophene derivative (partially oxidized), were formulated. The properties and corrosion resistance of the four alkyd coatings have been characterized. Among the three modified paints, the one containing polythiophene shows the best adherence and the highest corrosion resistance. This has been attributed to the fact that the miscibility of the polythiophene derivative with the alkyd formulation is better than that of polyaniline. Furthermore, accelerated corrosion assays and electrochemical impedance spectroscopy measurements revealed that the corrosion resistance of the paint with polythiophene is several orders of magnitude higher than that with zinc phosphate. The polythiophene derivative has been found to induce the formation of a passivating and well-adhered layer between the coating and the surface, preventing the access of chloride anions and oxygen to the substrate.     

Improvement of anticorrosive performance of phosphate-based alkyd paints with suitable additives

The purpose of this investigation was focused on reducing the content of zinc phosphate in anticorrosive paints by means of the incorporation of low quantities of selected soluble corrosion inhibitors. The article describes the anticorrosive behavior of alkyd paints containing reduced levels of zinc phosphate, zinc oxide, and some soluble compounds used as additives (e.g., sodium polyphosphate, sodium phosphate, and sodium benzoate). Anticorrosive solventborne alkyd paints were formulated with a zinc phosphate content of 10% by volume (v/v) with respect to the total pigment concentration. In all cases, the PVC/CPVC (pigment volume concentration/critical pigment volume concentration) ratio was 0.8. Experimental paints, applied on sandblasted SAE 1010 panels, were evaluated by accelerated tests (salt spray cabinet) and electrochemical measurements (electrochemical impedance spectroscopy, EIS). The results show that the additions of small amounts of soluble corrosion inhibitors to low content zinc phosphate paint formulations enhance their performance in a very remarkable way. Perhaps, the most outstanding feature is that the employment of soluble additives allowed the reduction of the zinc phosphate content with concomitant savings.     

Stabilization of aluminum pigment in waterborne paints

The corrosion of aluminum pigments in aqueous alkaline paint media, which results in the evolution of hydrgen, can be inhibited by certain substances. The combination of noninhibiting paint resins with three corrosion inhibitors (salicylic acid, a fluorinated phosphate surfactant, and an epoxy ester resin) has been studied. The presence of the resins does not significantly affect the stabilization of the aluminum pigment at pH 10 by the corrosion inhibitors. With the addition of corrosion inhibitors, the hydrogen volume evolved from aqueous aluminum pigment dispersions is surprisingly reduced by stirring. However, when heated to +40°C aqueous aluminum pigment dispersions with inhibitors evolve more hydrogen; at pH 8 the results are still satisfactory even at +40°C.     

A method for preparation and application of micronized ferrite pigments in anticorrosive solvent-based paints

This work presents a method of preparing single-, double-, and triple-cation ferrite pigments by employing simple chemical techniques to study their corrosion protection properties. The prepared pigments were characterized using X-ray diffraction and scanning electron microscopy. All prepared ferrite pigments were evaluated using ASTM methods. Anticorrosive paint formulations were performed using different prepared pigment loadings. The physico-mechanical and corrosion properties of dry paint films were examined. The tests revealed that the prepared ferrite pigments show excellent anticorrosive behavior, and that the best among them in performance are zinc and zinc magnesium. Calcium, zinc–calcium, and zinc–magnesium–calcium ferrites show better performance in high pigment loadings, while magnesium ferrite pigments show good results only in low pigment loading.     

卡拉胶改性三聚磷酸铝对水性环氧涂层防腐性能的影响

采用卡拉胶(KC)对三聚磷酸铝(ATP)进行接枝改性获得了KC-ATP填料,再将其添加到水性环氧树脂(WEP)中制备了复合防腐涂层.通过FTIR、XPS、TG、SEM对ATP改性前后的形貌、结构进行了表征.采用电化学阻抗谱(EIS)和盐雾实验考察了复合涂层的防腐性能.结果表明,KC成功地接枝到ATP表面,改善了ATP的...