JP2002167439A - Aluminum (poly)phosphate-siloxane cocondensate, method for producing the same, and sealant containing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a material effectively applicable to a sealant which has low viscosity and enables it to penetrate into a cell and a space existing in a metal sprayed film, and when it is cocondensed, forming a cured product good in flexibility, impact resistance, water resistance, chemical resistance and corrosion resistance to bring the film into completely free from the cell and the space and consequently giving a long life protection to the filmed sur face of a base material. SOLUTION: A newly developed aluminum (poly)phosphate-siloxane cocondensate is applicable to the sealant by specifying its atomic ratio of phosphorus (P) : aluminum (Al) : Silicon (Si) to 1-3:1:8-1,040.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method for forming a coating on the surface of a material by, for example, thermal spraying. The present invention relates to a novel (poly) aluminum phosphate siloxane co-condensate useful as a sealant, that is, a material that blocks and protects the material surface from gas and liquid intrusion, a method for producing the same, and its use as a sealant. .

[0002]

2. Description of the Related Art Conventionally called a thermal spraying method, a metal material such as steel is made to be in a molten state on the surface of the material for the purpose of rust prevention, corrosion prevention, abrasion resistance, heat resistance, heat insulation, etc., and decoration. There is known a method of spraying fine particles of a heated metal, alloy, ceramic (for example, metal oxide, metal carbide, or the like) or an organic material, and laminating the particles to form a film. In recent years, this thermal spraying method has been used in a wide range of fields such as construction, civil engineering, shipbuilding, machinery, electricity, etc. with the increasing demand for metal materials that can withstand various conditions and the improvement of thermal spraying equipment, thermal spraying materials, and thermal spraying method. Usage is expanding.

[0003] The thermal spraying method is a method in which a linear, rod-like, or powdery thermal spray material is heated and melted with a heat source to form a liquid, atomized with air or an inert gas (such as nitrogen or argon), and sprayed onto a surface to be sprayed. Depending on the heat source for heating, it can be broadly classified into gas-type thermal spraying and electric thermal spraying. Gas spraying includes flame spraying and explosive spraying. Flame spraying can be further divided into a hot-wire type, a hot-dip type and a powder type.
In the thermal spraying type and the hot rod type, the thermal spraying material is sent from the center hole of the torch, the thermal spraying material is melted with an oxygen-combustion flame, and it is atomized with a jet of compressed air from the surroundings and blown off and hit against the material surface In close contact. In the powder type, a sprayed material powder is supplied from a hopper into a supply gas (oxygen-fuel gas is divided and flows through a center hole), and the molten material is put into a molten state from a nozzle outlet by a high-temperature combustion gas flow. , Spray on the material surface. Explosive spraying is a method in which metal or ceramic powder is explosively melted and sprayed.

The electric type includes arc type thermal spraying and plasma thermal spraying. The arc method is a method in which an arc is generated at the tip of two sprayed materials (lines) which are continuously fed, and the melted portion is blown as fine particles onto the material surface by an air jet blown out from a center hole. Plasma spraying is a method in which an arc generated between a tungsten cathode and the inside of a nozzle hole of a copper anode is used as a heat source to melt a sprayed material powder, and the molten powder is put on a working gas and struck against the material surface. In any case, the thermal spraying method is a method in which fine particles of a thermal spray material in a molten state are sprayed onto a surface to be sprayed to form a film. Therefore, a large number of fine pores are present in the formed thermal spray coating. There are open pores and closed pores in the pores scattered in the thermal spray coating, but since the open pores allow gas and liquid to penetrate from the coating surface to the material surface through these pores, it is necessary to block these pores depending on the application. . It is what is called a sealing agent that is applied to the thermal spray coating for the purpose of closing the pores.

[0005]

The sealing agents which have been used include oils and fats, waxes, synthetic resins such as epoxy resins, polyurethane resins, polyester resins and phenol resins, ceramic materials such as water glass, and the like. Phosphates,
Although there are inorganic sealing agents such as dichromates, mainly synthetic resin sealing agents have been used. However, the synthetic resin sealing agent has too large a molecule of the high molecular polymer as a component, and cannot penetrate into the pores having a small diameter in the thermal spray coating to the inside thereof, but only coats the surface. In addition, the films made of these synthetic resins are relatively easy to peel off, and once peeled off, the pores are regenerated and water and gas penetrate to the material surface,
If the material surface is made of metal such as iron, it may cause rust. Therefore, bridges with one major purpose of rust prevention,
It is desired that a sealing agent used for a large facility exposed to wind and rain, such as a steel tower and an outdoor plant, has at least the following requirements.

[0006] 1. Low viscosity. 2. Easy to penetrate pores and voids. 3. High solids content. 4. Good adhesion to top coat. 5. Hardens after penetrating into pores and voids. 6. It is flexible and has high impact resistance. 7. Water resistance, chemical resistance, and corrosion resistance. 8. Heat resistant to the intended use temperature of the thermal spray coating. However, none of the conventionally used sealing agents satisfy the above requirements.

[0007]

In view of the above circumstances, the present inventors have synthesized a large number of compounds, prepared various compositions, and searched for a material having the above requirements for the sealing agent. As a result, surprisingly, phosphorus (P), aluminum (A)
l) that the (poly) aluminum phosphate siloxane cocondensate having an atomic ratio of silicon (Si) in a specific range satisfies all the requirements for the above-mentioned sealing agent,
After further studies, the present invention was completed. That is, the present invention Wherein R ¹ is hydrogen, C _1-18 alkyl or aryl, R ² , R ³ and R ⁴ are the same or different and
_{Represents 1-3} alkyl. ), (Poly) phosphoric acid and aluminum hydroxide are represented by P
/ Poly (aluminum) phosphate condensate (b) condensed at an atomic ratio of 1 to 3 in an amount of 8 to 1040 with an Si / Al atomic ratio of Si in (a) and Al in (b). (2) the (poly) aluminum phosphate siloxane co-condensate according to (1), wherein the (poly) aluminum phosphate siloxane co-condensate obtained by reacting at a ratio of (1) The (poly) aluminum phosphate siloxane co-condensate according to (1) or (2), which has a viscosity of 5 to 100 cP. Wherein R ¹ is hydrogen, C _1-18 alkyl or aryl, R ² , R ³ and R ⁴ are the same or different and
_{Represents 1-3} alkyl. ) Is mixed with P / Al at a temperature of not more than 20 ° C while stirring under moisture protection.
The (poly) aluminum phosphate condensate (b) condensed at an atomic ratio of 1 to 3 has an Si / Al atomic ratio of 8 to 1040.
A method for producing a (poly) aluminum phosphate siloxane cocondensate, which is added little by little until the reaction is completed, (5) Si /
(Poly) according to (4), wherein the Al atomic ratio is 80 to 300.
A method for producing an aluminum phosphate siloxane co-condensate, and (6) a sealing agent containing the (poly) aluminum phosphate siloxane co-condensate according to any one of (1) to (3).

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The (poly) aluminum phosphate siloxane co-condensate of the present invention is a novel substance which has not been described in any literature, and comprises a siloxane compound (a) represented by the formula and (poly)
It can be obtained by condensing the aluminum phosphate condensate (b) so as to have a specific Si / Al atomic ratio. In the formula, C _1-18 alkyl represented by R ¹ includes methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, and n-alkyl.
Octyl, n-nonyl, n-decyl, n-undecyl,
n-dodecyl and the like; and aryl as phenyl and the like. Preferred alkyl groups are alkyl of _{C 6-1 2.} Examples of the alkyl represented by R ² , R ³ and R ⁴ include methyl, ethyl, n-propyl and the like. The preferred alkyl is methyl.

[0009] The (poly) phosphoric acid includes polyphosphoric acid in the form of two or three orthophosphoric acids such as oritoric acid, diphosphoric acid and triphosphoric acid. The (poly) aluminum phosphate condensate (b) in which (poly) phosphoric acid and aluminum hydroxide are condensed usually has an atomic ratio of P / Al of 1
To 3, preferably 1 to 1.5. (A) and (b)
Having an atomic ratio of Si / Al of 8 to 1040, preferably 80
The polycondensation product (poly) aluminum phosphate siloxane co-condensate of the present invention can be obtained by condensing in a quantitative ratio such that it is from 300 to 300, more preferably from 100 to 200.

Next, a production example of the (poly) aluminum phosphate siloxane cocondensate of the present invention will be described. First, (Poly)
The aluminum phosphate condensate (b) can be obtained, for example, by dispersing aluminum hydroxide powder in an acetic acid solution of citric acid, and adding an equimolar orthophosphoric acid under stirring to cause a reaction. Further, when citric acid and amorphous aluminum citrate are mixed, a slurry is formed, and a transparent liquid (poly) aluminum phosphate condensate can be obtained by adding a small amount of water to the slurry. Next, the siloxane compound (a) is contained in a reactor,
The reaction temperature is kept at 20 ° C. or lower, preferably 5 to 15 ° C. under the condition of shutting off moisture, for example, under the flow of dry nitrogen gas, and the (poly) aluminum phosphate condensate (b) is added little by little and stirred. Then, a predetermined amount is reacted in such a manner that the liquid becomes clear and the next small amount is added.

The co-condensate thus obtained is neutralized by passing ammonia gas if necessary, and adsorbent such as silica gel is added as necessary to adsorb and remove water and neutralized salts. A clear, liquid (poly) ammonium phosphate siloxane co-condensate having a viscosity of 100 cP is obtained. This co-condensate and a cured product of the co-condensate have the following properties. Properties of co-condensate It is a transparent liquid in the visible and infrared regions. 2. The viscosity is 5 to 100 cP, and although it is viscous, it has high penetration into the pores of the sprayed coating. 3. At the surface of the metal or metal oxide, it is further condensed, cured and adhered. 4. Curing at the air-contacting surface is slow, and complete curing usually takes approximately 24 hours. Properties of cured product of co-condensate It is transparent glass and flexible. 2. The surface of the cured product has water repellency and chemical resistance. 3. The ratio ranges from 1.10 to 1.30. 4. Refractive index is in the range of ^N ₂₅ D = ^1.37~1.54. 5. The pencil has a hardness of 2H to 3H and has flexibility.

The thermal sprayed film formed on the material surface by the thermal spraying method has a thickness of 10 to 1000 μm, usually about 50 to 300 μm, but the film is porous and has a porosity of 2 to 50 μm.
20%. The pore size varies depending on the thermal spraying material and the thermal spraying method, but most are 10 μm or less, and the average pore size is 0.05.
It is often between 0.1 μm and 0.1 μm. Therefore, it is desirable that the sealing agent penetrates into the pores of about 0.05 to 10 μm and reaches the material surface. Although the (poly) aluminum phosphate siloxane co-condensate of the present invention is a slightly viscous liquid, it penetrates well into these fine pores, condenses and hardens in the pores and on the material surface, and becomes vitreous. It becomes a flexible cured product having high water repellency and chemical resistance. The cured product also has good adhesiveness with general synthetic resin paints. As described above, the co-condensate of the present invention has properties extremely suitable as a sealing agent, but also has good adhesion to metals, ceramics, cements and the like, and is therefore useful as a surface protective agent for these. .

In order to apply the sealing agent to the surface of the thermal sprayed coating, a method used for applying a general paint such as spraying with an air gun or a brush can be used as it is, but spraying with an air gun is effective in operation. But preferred.
Generally, the coating material is 10 to 10 depending on the thickness of the thermal spray coating.
It is about 200 g / m ² , preferably about ²⁰ to 150 g / m ² . The sealing agent applied to the sprayed coating surface penetrates into the pores relatively quickly, but slowly condenses and hardens within several hours to 24 hours.

[0014]

The present invention will be specifically described below with reference to examples and test examples. Example 1 0.3 g of citric acid was dissolved in 2.0 ml of acetic acid, and 4.7 g of aluminum hydroxide powder was dispersed in the solution.
Orthophosphoric acid was added dropwise in equimolar amount to the aluminum hydroxide with stirring to obtain a slurry-like aluminum phosphate condensate. Hexyltriethoxysilane (KBE3063, manufactured by Shin-Etsu Chemical Co., Ltd.)
1000 ml was accommodated, a sealed stirrer was attached to the center neck, and dry nitrogen gas was introduced from the other neck to shut off moisture. The Kolben was fixed in a water bath maintained at 10 ° C.
From the other neck, 2 min / min until the aluminum phosphate reaches a total of 4% by weight of hexyltriethoxysilane.
The reaction was performed by adding each ml. After the completion of the addition of the aluminum phosphate, the mixture was further stirred for 1 hour to obtain an aluminum phosphate siloxane cocondensate (Si / Al atomic ratio: 8/1) as a transparent and stable viscous liquid. Ammonia gas was introduced into the solution to neutralize the solution, and granular silica gel was added to adsorb and remove moisture and neutralized salts. The solution had a viscosity of 41 cP and a specific gravity of 1.2.
An aluminum phosphate siloxane co-condensate of 6 (20 ° C.) was obtained.

Example 2 When 3.0 g of amorphous aluminum phosphate was mixed with 3.0 g of citric acid monohydrate, a slurry-like aluminum phosphate condensate was obtained. A few drops of water (0.
25 ml) to give a clear liquid. The same hexyltriethoxysilane 100 as used in Example 1 was used for this solution.
2m per minute in a 2000ml Kolben containing 0ml
1 was added dropwise. After adding a slurry-like aluminum phosphate condensate until the Si / Al atomic ratio reaches 8/1,
When stirring was further continued for 1 hour, a clear viscous liquid was obtained.
After neutralizing the solution through ammonia gas, granular silica gel was added to adsorb and remove water and neutralized salts, and the specific gravity was 1.130.
(20 ° C.), an aluminum phosphate siloxane co-condensate having a viscosity of 45 cP was obtained.

Example 3 3 mol of aluminum hydroxide was added to 1 mol of sodium tripolyphosphate, 1.5 mol of citric acid and a little sulfuric acid were added, and the mixture was kneaded with an extruder. This one
When 1 liter of ethyl alcohol was added, water was separated, and a paste-like aluminum tripolyphosphate condensate was obtained.
4 in a 50 l stainless steel kettle with jacket and stirrer
After adding 0 kg of decyltrimethoxysilane, filling with dry nitrogen gas, and stirring, 800 g of the obtained aluminum tripolyphosphate cocondensate was added dropwise over about 3 hours, and the liquid became transparent from the glass window. I checked. 20 g of silica gel was added at the time of completion of clearing, and excess neutralized salt was adsorbed and removed to obtain a specific gravity of 1.26 and a viscosity of 42 cP.
Polyphosphorus aluminum siloxane cocondensate (Si
/ Al atomic ratio: 170/1) was obtained.

Test Example 1 Sealing Test of Thermal Sprayed Coating The aluminum phosphate siloxane co-condensate obtained in Examples 1 and 2 was applied to a sprayed coating of a zinc-sprayed steel sheet of 5 cm × 10 cm (manufactured by Niigata Metallicon Co., Ltd.). Then, the sealing effect was evaluated. For comparison, a similar experiment was performed using an epoxy resin paint (Nippon Paint Co., Ltd., Hypon 30 mastic primer) used as a sealing agent. Material surface treatment: blast treatment (grit 1
00 #) Spraying method: Flame spraying using oxygen-acetylene gas Spraying material: Zinc Sprayed film thickness: 70 μm Coating method: Air spray (0.3 mm in diameter, ejection pressure 0.13 Mpa, manufactured by Meiji Kikai Seisakusho) from the sprayed surface Coating from a distance of 20 cm Coating amount: 35 g / m ² Curing condition: Leave at 25 ° C. for 10 hours Evaluation test

(1) Saltwater resistance test According to the corrosion resistance test of the thermal sprayed coating of JIS-H8300, the test piece was immersed in a 3% saline solution at 40 ° C for 72 hours, and the presence or absence and degree of swelling, peeling, red rust on the coated surface were measured. Was visually observed. (2) Potassium ferrocyanide color development test In order to evaluate the permeability of the acid, potassium ferrocyanide was dissolved in distilled water to prepare a 3% solution, and sulfuric acid was added to adjust the pH to 4.5 to 5.0. The surfactant octadecylmonomethylammonium sulfate is added in 0.05%.
In addition, at room temperature, the test piece was immersed every 12 hours for 60 minutes and pulled up, and this operation was repeated six times. During that time, the coloration of Prussian blue due to the reaction between potassium ferrocyanide and iron rust was observed.

[0019]

[Table 1] As is clear from Table 1 above, Examples 1 and 2
The aluminum phosphate siloxane co-condensate obtained in step (1) penetrates into the pores of the zinc sprayed coating and hardens inside to completely close the pores, effectively preventing water from entering from outside and protecting the material surface I do. On the other hand, with epoxy resin paint,
The coating hardly penetrated into the pores, and bubbles generated on the surface remained as craters. As a result, 24-36
After an hour, white rust due to saline was observed.

Test Example 2 Sealing test of sprayed surface Aluminum polyphosphate synthesized in Example 3 on a 5 cm x 10 cm steel plate (prepared by Japan Metallizing Rust Prevention Association) prepared by arc spraying of a pseudo alloy of aluminum and zinc. Sealing treatment was performed with a siloxane co-condensate. For comparison, the same treatment was performed using silicate 40 (manufactured by Tama Chemical Industry Co., Ltd.) as a silicate sealing agent. Thermal spraying: Simultaneous room temperature arc spraying of blasted aluminum and zinc (Al / Zn volume ratio = 55/45) Thermal sprayed film thickness: 100 μm, 200 μm Coating method: same as in Test Example 1 Coating amount: 150 g / m ² Drying time: 24 hour evaluation test (1) Salt tolerance test (same procedure as in Test Example 1) (2) Potassium ferrocyanide color development test (same procedure as in Test Example 1) (3) 1N hydrochloric acid 1 hour immersion test (25 ° C)

[0021]

[Table 2] For the sprayed coating formed on the steel plate by the arc sprayed coating using aluminum as a spraying material, the sealing agent of Example 3 well penetrates into the pores, condenses and hardens inside to close the pores, and as a result, The material surface was protected for a long time against salt water and acid. On the other hand, the silicate sealing agent contracted after application, and the application layer was cracked. Brine and acid penetrate into the inside from the cracks, causing white rust on the surface of the material and causing a phenomenon of erosion.

[0022]

The novel (poly) aluminum phosphate siloxane co-condensate of the present invention is a liquid having a relatively low viscosity, penetrates into the pores and voids existing in the thermal spray coating, and condenses slowly. It becomes a glassy cured product with flexibility, impact resistance, water resistance, chemical resistance, corrosion resistance, and heat resistance. It completely seals pores and voids and protects the material surface for a long time. Therefore, it is extremely suitable as a sealing agent for a thermal spray coating. It is also useful as a general paint for protecting the material surface.

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Hideyuki Ishibashi 3-1-29-1 Kihara, Saga City, Saga Prefecture (72) Inventor Shunichi Unino 1-10-5-401 Sawayoshinishi, Ibaraki-shi, Osaka F-term (reference) 4H017 AA04 AB16 AB17 AC15 AD06 AE05 4H050 AB46 AB99 AC90 WA13 WA29 4J035 BA01 CA29N CA291 HA05 HB02 LA02 LB20 4K031 AB02 AB09 CB31 FA08

Claims (6)

[Claims] (1) Expression Wherein R ¹ is hydrogen, C _1-18 alkyl or aryl,
R ² , R ³ and R ⁴ are the same or different, and
_{Represents 1-3} alkyl. ), (Poly) phosphoric acid and aluminum hydroxide are represented by P
/ Poly (aluminum) phosphate condensate (b) condensed at an atomic ratio of 1 to 3 in an amount of 8 to 1040 with an Si / Al atomic ratio of Si in (a) and Al in (b). (Poly) aluminum phosphate siloxane co-condensate obtained by reaction at a specific ratio. 2. The copolycondensate of (poly) aluminum phosphate siloxane according to claim 1, wherein the atomic ratio of Si / Al is 80 to 300. 3. The copolycondensate of (poly) aluminum phosphate siloxane according to claim 1, which has a viscosity of 5 to 100 cP. (4) Wherein R ¹ is hydrogen, C _1-18 alkyl or aryl, R ² , R ³ and R ⁴ are the same or different and
_{Represents 1-3} alkyl. ) Is mixed with P / Al at a temperature of not more than 20 ° C while stirring under moisture protection.
The (poly) aluminum phosphate condensate (b) condensed at an atomic ratio of 1 to 3 has an Si / Al atomic ratio of 8 to 1040.
A method for producing a (poly) aluminum phosphate siloxane co-condensate, which is added little by little until the reaction is completed. 5. The process for producing a (poly) aluminum phosphate siloxane co-condensate according to claim 4, wherein the Si / Al atomic ratio is from 80 to 300. 6. The (poly) according to claim 1, wherein
A sealing agent containing an aluminum phosphate siloxane cocondensate.