JP2009067819A - Antistatic coating and product coated therewith - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an antistatic coating exhibiting antistatic function without being compounded with any electrically conductive metal oxide at all and having water resistance as well, and to provide a product exhibiting antistatic function as a result of being coated therewith. <P>SOLUTION: The antistatic coating is such that a polytetrafluoroethylene resin with graft-polymerized sulfo groups has been compounded at 10 mass% or greater in the total resin component constituting the coating. A product with a surface resistivity of 1×10<SP>9</SP>Ω/SQUARE or less is obtained by coating a substrate with the above coating. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a paint and a coated product, and more particularly to an antistatic paint having an antistatic function and water resistance and a coated product thereof.

  In general, the composition of a paint consists of an organic resin as a film forming material, a pigment (organic or inorganic) as a coloring material, an organic solvent that imparts fluidity to the material, and an additive that adjusts the paint / coating film. In this case, since the organic resin generally has high electric resistance, the electric resistance of the coating film made of the organic paint is also high. Therefore, in order to lower the electrical resistance of the paint film, it is necessary to add a conductive pigment or to mix a water-soluble resin.

  However, the method of adding a specific pigment is not limited to a specific color, and the method of mixing a water-soluble resin has a problem that the water resistance of the coating film is poor.

  In addition, when the electrical resistance value of the coating film increases, static electricity tends to accumulate on the surface of the coating film, causing the problem of adsorbing dust due to static electricity, and if the dust adheres to the coating film surface, the transparency of the coating film Decreases.

On the other hand, in order to exert the antistatic function on the surface of the coating film, it is common general knowledge that the surface resistance value is 1 × 10 ⁹ Ω / □ or less.

Therefore, as a prior art relating to this type of antistatic coating, an antistatic coating having a surface resistance value of 1 × 10 ⁴ to 1 × 10 ⁹ Ω / □ has been filed for a patent (for example, Patent Document 1). reference).

In addition, it is desired that a coated product to which this kind of antistatic coating is applied has not only an antistatic function but also excellent weather resistance and antibacterial properties. In particular, paint products used outdoors such as building exterior walls, car body steel plates, and tents have a good appearance and are difficult to adhere to dirt such as water stains and rainwater traces, such as contamination resistance (environmental contamination resistance). It is desirable to have
JP 2005-22155 A

  The antistatic paint described in Patent Document 1 is an antistatic paint containing a conductive metal oxide and exhibits an antistatic effect. However, in order to maintain the transparency of the coating film, the conductive metal oxide to be blended is used. It is necessary to devise a method for reducing the particle diameter of the conductive metal oxide and making the blending ratio of the conductive metal oxide within a predetermined range, which is not easy.

  Moreover, it is desirable that the coating film of the coated product to which the antistatic coating is applied not only has transparency to the extent that the color and pattern of the base can be easily revealed, but also has water resistance.

  In order to solve the above problems, an object of the present invention is to provide an antistatic paint that exhibits an antistatic function without blending any conductive metal oxide and has water resistance. Another object is to provide a coated product that exhibits an antistatic function when applied.

  In order to achieve the above object, the antistatic coating material of the invention according to claim 1 is blended with polytetrafluoroethylene resin in which sulfonic acid groups are graft-polymerized in an amount of 10% by mass or more in the total resin components constituting the coating material. It is characterized by that.

  According to the invention according to claim 1 having the above-described configuration, since the resin having a sulfonic acid group serving as a hydrophilic group in the side chain is blended in an amount of 10% by mass or more, the cation exchange resin function in which the resin itself attracts cations , Hydrogen ions permeate freely, exhibit ionic conductivity, and the resin itself exhibits an antistatic function.

  As described in claim 2, porous titanium oxide having a photocatalytic function can be further blended.

  According to invention of Claim 2, while exhibiting stain resistance by a photocatalyst function, since the porous titanium oxide is mix | blended, a deodorizing function is fully exhibited.

The invention described in claim 3 is characterized in that the antistatic paint according to claim 1 or 2 is applied to a base material to obtain a coated product having a surface resistance value of 1 × 10 ⁹ Ω / □ or less.

  According to the invention of claim 3 having the above-described configuration, the antistatic function is exhibited.

As described in claim 4, it is preferable that the coating thickness of the antistatic coating material is 1 μm, the visible light transmittance is 90%, and the surface resistance value is 10 ⁸ Ω / □ or less.

  According to the invention according to claim 4 having the above-described configuration, since the visible light transmittance is as high as 90% and has excellent transparency, the transparency of the coating film can be stably maintained for a long period of time. Can do. Moreover, even if the coating film thickness is as thin as 1 μm, the surface resistance value can be suppressed sufficiently low, and the antistatic function is exhibited.

  As described in claim 5, the base material can be a fluororesin-coated panel.

  According to the invention according to claim 5 having the above-described configuration, since the base material is a fluororesin-coated panel, it has weather resistance, exhibits an antistatic function by applying an antistatic paint, and further titanium oxide. A panel exhibiting a photocatalytic function can be obtained by blending.

  As described above, according to the present invention, the resin having a sulfonic acid group serving as a hydrophilic group in the side chain is blended in an amount of 10% by mass or more in the resin component, so that the resin can be obtained without blending any conductive metal oxide. It is possible to obtain an antistatic paint that exhibits an antistatic function and has water resistance. Furthermore, by applying an antistatic coating containing titanium oxide, it is possible to obtain a coated product having not only an antistatic function but also excellent stain resistance, weather resistance and antibacterial properties.

  Hereinafter, embodiments of the antistatic paint and the coated product thereof according to the present invention will be described in detail.

  The antistatic paint according to the present invention is a paint in which a polytetrafluoroethylene resin in which a sulfonic acid group is graft-polymerized is blended as a resin component for forming a film. As the resin, for example, Nafion (Dupont) Registered trademark). Further, the blending ratio of the polytetrafluoroethylene resin is desirably 10% by mass or more based on the total resin components constituting the coating material.

  This is because the polytetrafluoroethylene resin is a resin having a sulfonic acid group serving as a hydrophilic group in the side chain, so that the resin itself is a cation exchange resin that attracts cations, and hydrogen ions can freely pass therethrough. This is because the ionic conductivity is exhibited, and therefore the resin itself exhibits an antistatic function when blended in the resin in a predetermined ratio or more.

  Furthermore, it is also possible to prepare an antistatic coating material that exhibits a photocatalytic function by blending porous titanium oxide having a photocatalytic function in the resin.

  For example, as a resin binder in which other fluororesin is blended in addition to polytetrafluoroethylene resin, titanium oxide can be added to the binder to form a photocatalyst paint. Fluororesin to be blended includes PVDF, PVF, PTFE, ETFE, PVDF-HFP, PCTFE, trifluorochloroethylene-alkyl vinyl ether copolymer, tetrafluoroethylene-alkyl vinyl ether copolymer, trifluoroethylene chloride At least one kind of alkyl vinyl ether-alkyl vinyl ester copolymer can be used. Moreover, it is also possible to mix | blend 2 or more types of fluororesins.

  By using a photocatalyst coating containing these known fluororesins, the adhesion to metals and inorganic bases is improved, and the wear resistance of the coating film is improved.

  Next, Nafion (registered trademark of DuPont) used as a polytetrafluoroethylene resin will be described.

  Nafion (registered trademark) is a polytetrafluoroethylene in which sulfonic acid groups are graft-polymerized, and is an organic polymer generally used as a solid electrolyte of a polymer solid fuel cell. It is represented by

  As represented by the above chemical formula, the Nafion (registered trademark of DuPont) is a graft polymer (a sulfonic acid group having a perfluorosulfonic acid side chain containing a repeating unit of polymer tetrafluoroethylene having a side chain. Graft-polymerized poly (tetrafluoroethylene), which has no C—H bond and is a highly stable C—F bond with respect to an electrochemical reaction, and is therefore not susceptible to photocatalysis. It can be said.

  The bond energy of C—F bond is large and forms a very dense and stable molecular chain. Therefore, it has high crystallinity, chemical resistance and weather resistance, and is highly resistant to electrochemical reaction. In addition, the small atomic radius and low polarizability of the F atom reduce the intermolecular cohesive force, and the properties of low surface tension and low friction coefficient make it easy to deform to external force. Conceivable. (Refer to page 306 of Encyclopedia of Plastics and Functional Polymer Materials: Published by Industry Research Association Encyclopedia Publishing Center (2004)).

  Since Nafion (registered trademark) is used as a resin binder for the paint, even if a metal oxide having a photocatalytic function is blended, the binder is not easily subjected to photocatalytic action, and self-collapse does not occur. Moreover, even if it increases the compounding quantity of the photocatalyst metal oxide to mix | blend, a binder does not deteriorate. Therefore, it is possible to increase the concentration of the metal oxide to the extent that it can be applied as a paint.

  If it is a coating material containing a photocatalytic metal oxide, it exhibits super hydrophilicity and is less susceptible to environmental pollution. Furthermore, it is also possible to exert other deodorizing functions and antibacterial functions, which are other photocatalytic functions.

  In order to sufficiently exhibit the deodorizing function and antibacterial function described above, the coating film itself needs to have a sufficient gas adsorption capacity. To that end, the adsorption surface area of the coating film may be increased. Further, in order to increase the adsorption surface area of the coating film, a metal oxide such as titanium oxide blended in the coating material having a large specific surface area may be employed. For example, porous titanium oxide manufactured by Ishihara Sangyo Co., Ltd. ST-01 can be used.

  As the metal oxide having a photocatalytic function, titanium oxide, zinc oxide, tin oxide, and the like are present. In particular, titanium oxide that has a stable photocatalytic function and is easily available is preferably used. The titanium oxide is in the form of fine particles, and a predetermined amount of the titanium oxide is mixed in an appropriate resin binder, an organic solvent, water, and the like, and stirred to produce a predetermined photocatalyst paint.

  Next, an example in which the surface resistance value of the coating film was measured (measured using an insulation resistance tester SM-8220 (manufactured by Hioki Electric Co., Ltd.)) will be described.

  Sample: A solution using a 5% Nafion solution “DE520” (DuPont product) as a polytetrafluoroethylene resin graft-polymerized with sulfonic acid groups, and a cross-linked fluororesin “Lumiflon 710F” (Asahi Glass product) 8 B solution prepared by mixing and stirring 0.0 parts by mass, 3.5 parts by mass of methylated melamine resin “Super Becamine L-105-60” (Dainippon Ink Chemical Co., Ltd.) and 88.5 parts by mass of methyl ethyl ketone as a solvent; Were mixed at a predetermined ratio to prepare an antistatic paint.

  The resin component of said A solution will be 5 mass% with respect to 100 mass parts. In addition, the resin component of the solution B is a cross-linked fluororesin “Lumiflon 710F” (product of Asahi Glass Co., Ltd.), which is a solid with a non-volatile content of 100% by mass, and methylated melamine resin “Super Becamine L-105-60” Ink Chemical Industries Co., Ltd.) is a highly viscous liquid having a nonvolatile content of 60% by mass, so that the B solution as a whole is 10% by mass with respect to 100 parts by mass of the B solution.

  Therefore, Example 1 (antistatic coating 1) with 100% A solution has a polytetrafluoroethylene resin content of 100% by mass, and 50 parts by mass of B solution is mixed with 100 parts by mass of A solution. In Example 2 (antistatic coating 2), the blending ratio of the polytetrafluoroethylene resin in the resin component is 50% by mass. Furthermore, in Example 3 (antistatic coating material 3) in which 50 parts by mass of the A solution and 100 parts by mass of the B solution were mixed, the blending ratio of the polytetrafluoroethylene resin in the resin component was 20% by mass. Further, in Example 4 (antistatic coating 4) in which 50 parts by mass of A solution and 220 parts by mass of B solution were mixed, the blending ratio of the polytetrafluoroethylene resin in the resin component was 10% by mass. In Example 5 in which 10 parts by mass and 90 parts by mass of the B solution were mixed, the blending ratio of the polytetrafluoroethylene resin in the resin component was 5% by mass. Furthermore, it is clear that with only the B solution (Comparative Example 1), the blending ratio of the polytetrafluoroethylene resin in the resin component is 0% by mass.

  Samples obtained by applying these six types of paints of Examples 1 to 5 and Comparative Example 1 to an acrylic plate and drying were prepared, and surface resistance values were measured and water resistance tests were performed.

  The coating method at this time is spray coating, and the coating film thickness is 1 μm by drying at 140 ° C. for 5 minutes. However, the coating method and the drying method may be other methods and are not particularly limited.

  Measurement Example 1: Table 1 shows the results of measurement using the above sample.

  Actual measurement example 2: Furthermore, as a transparent conventional antistatic coating material of Comparative Example 2, 40 parts by mass of polymethacrylic acid aqueous solution “Jurimer SP-50TF” (product of Nippon Pure Chemical Co., Ltd.) and 60 parts by mass of isopropyl alcohol were mixed. Using the adjusted polymethacrylic acid resin alcohol solution, the surface resistance value was measured and the water resistance test was performed under the same conditions as in Comparative Example 1 above. The results are shown in Table 2.

  Measurement Example 3: Example 3 (antistatic coating 3) described above was applied to a different type of substrate (coating thickness 1 μm), and the surface resistance at that time was measured. The results are shown in Table 3.

As shown in Table 1, when the blending ratio of the polytetrafluoroethylene resin of Example 1 according to the present invention is 100% by mass in the resin component, the coating thickness is as very thin as 1 μm. However, it can be seen that the surface resistance value is low at 10 ⁵ Ω level.

Further, in Example 2 where the blending ratio of the polytetrafluoroethylene resin is 50% by mass in the resin component, the level is 10 ⁶ Ω, and the blending ratio of the polytetrafluoroethylene resin is 20% by mass in the resin component. % Example 3 or 10% by mass Example 4 is 6.67 × 10 ⁷ Ω, which is below the 10 ⁸ Ω level.

Generally, if the surface resistance value is 10 ⁸ to 10 ⁹ Ω / □ or less, it is said that there is an antistatic effect, and Examples 1 to 4 according to the present embodiment are coating films that exhibit an antistatic function. Obviously it forms. That is, Examples 1-4 are antistatic paints.

However, the surface resistance value of Example 5 in which the blending ratio of the polytetrafluoroethylene resin in the resin component is 5% by mass is 10 ¹³ Ω level, and the antistatic function is not exhibited. That is, when the blending ratio of the polytetrafluoroethylene resin in the resin component is 10% by mass or more, the coating film exhibits an antistatic function.

  Further, all visible light transmittances of Examples 1 to 4 (measurement of transmittance at a wavelength of 550 nm using an ultraviolet / visible spectrophotometer “ShimadzuUV = 3150” (manufactured by Shimadzu Corporation)) is 90%. It can be seen that the coating film has excellent transparency. As for the water resistance, a dissolution phenomenon was observed in Comparative Example 2 (alcohol solution of polymethacrylic acid resin), which is a transparent conventional antistatic paint, from the results of a one-month tap water immersion test. No change is seen on the surface of the coating film to which the paint blended with the fluoroethylene resin is applied, indicating that the coating film has water resistance.

Therefore, if the blending ratio of the polytetrafluoroethylene resin is 10% by mass or more in the resin component, the visible light transmittance is 90% and the surface resistance value even if the coating thickness is 1 μm. Becomes 10 ⁷ Ω / □ level, and it is possible to form a coating film which is excellent in transparency and water resistance and exhibits an antistatic function.

Further, as shown in Table 3, the surface resistance value after applying the antistatic coating material is greatly reduced in any of the substrates as compared with before applying. Especially when baked fluororesin steel sheet of the base material is significantly decreased to 6.71 × 10 ⁵ after application from a previous surface resistance of 10 ¹⁵ levels or more applied.

Further, even in the case of an aqueous acrylic silicon coated aluminum plate, the 10 ¹² level has decreased to 10 ⁶ level, and it has become clear that the surface resistance value is sufficiently low to exhibit the antistatic effect.

As described above, if the surface resistance value is 10 ⁸ to 10 ⁹ Ω / □ or less, it is said that there is an antistatic effect, and the coated product coated with the antistatic paint 1 to 4 according to the present invention is antistatic. It is clear that it works.

However, in the elastic ricin (silicon) sprayed aluminum plate, the surface resistance value after application is reduced only to the 10 ⁹ level. This is thought to be because the actual surface area of the lysine surface is increased because the surface of the lysine is a sandy fine irregular surface.

  From the above results, it was found that the coated product to which the antistatic coating according to the present invention was applied has a coating film having a surface resistance value that is low enough to exhibit the antistatic function. Further, it was found that even when the thickness of the coating film was as thin as 1 μm, the surface resistance value was sufficiently low, and it was found to be effective as a clear coat requiring transparency.

  Further, when the antistatic coating according to the present invention is applied to a fluororesin-coated panel, the surface resistance value is greatly reduced, so that an excellent antistatic function can be imparted to a panel originally provided with weather resistance.

  In addition, by applying an antistatic coating containing titanium oxide having a photocatalytic function, it is possible to obtain an antistatic coating coated product excellent in not only the antistatic function but also stain resistance, weather resistance and antibacterial properties.

For example, by blending a predetermined ratio (for example, 1 to 10% by mass) of porous photocatalytic titanium oxide ST-01 (manufactured by Ishihara Sangyo Co., Ltd .: adsorption surface area 300 m ² / g), not only the antistatic function, An antistatic paint-coated product having a photocatalytic function excellent in contamination, weather resistance, and antibacterial properties can be obtained.

The antistatic paint according to the present invention is a paint containing a polytetrafluoroethylene resin in which a sulfonic acid group is graft-polymerized as a resin component forming the film, so that it has a large binding energy and is very dense and stable. A coating film of C—F bond forming a molecular chain is formed. Therefore, it has high crystallinity, chemical resistance and weather resistance, is highly stable to electrochemical reaction, and further, due to the small atomic radius and low polarizability of F atoms, intermolecular cohesive force , Exhibiting properties of low surface tension and low coefficient of friction. Further, since the surface resistance value is 10 ⁹ Ω / □ level or less, the resin itself exhibits an antistatic function and becomes an antistatic paint having water resistance.

  The antistatic paint coating product according to the present invention forms a thin antistatic film on the surface thereof, and thus forms a coating film excellent in transparency that can clearly express the color and pattern of the groundwork. The antistatic function is exerted to prevent dust from adhering to the surface of the coating film, resulting in a coated product having excellent contamination resistance.

  As described above, according to the present invention, the polytetrafluoroethylene resin in which the sulfonic acid group is graft-polymerized is blended in an amount of 10% by mass or more in the total resin components constituting the paint, so that the conductive metal oxide can be obtained. Even if it is not blended at all, it is possible to obtain an antistatic coating material which exhibits an antistatic function and has water resistance. Furthermore, by applying an antistatic paint containing titanium oxide, an antistatic paint coated product excellent not only in antistatic function but also in stain resistance, weather resistance and antibacterial properties can be obtained.

Claims (5)

An antistatic paint characterized in that polytetrafluoroethylene resin graft-polymerized with sulfonic acid groups is blended in an amount of 10% by mass or more based on all resin components constituting the paint. The antistatic paint according to claim 1, further comprising porous titanium oxide having a photocatalytic function. A coated product, wherein the antistatic paint according to claim 1 or 2 is applied to the surface of a substrate and has a surface resistance value of 1 × 10 ⁹ Ω / □ or less. The coated product according to claim 3, wherein the coating thickness of the antistatic coating is 1 µm, the visible light transmittance is 90%, and the surface resistance value is 10 ⁸ Ω / □ or less. The coated product according to claim 3 or 4, wherein the substrate is a fluororesin coated panel.