JPH0261799B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a conductive coated floor for preventing the occurrence of electrostatic damage in operating rooms, computer rooms, factories manufacturing electronic components such as LSIs, and the like.

(Prior Art) Conventionally, coating compositions have been applied to floor surfaces in order to form conductive floors. Some of these paint compositions contain graphite, conductive carbon black, metal powder, metal fibers, etc. in the vehicle, but these cannot be used as decorative floors because they are black or have a metal-specific color tone. It had drawbacks.

Taking this point into consideration, JP-A-57-
78464 and 59-145262 are disclosed.

(Problem to be solved by the invention) However, the paint composition shown in the former is intended to prevent accidents during work on high-voltage power transmission towers, and as specified in the electrostatic safety guidelines of the Ministry of Labor. Desired leakage resistance value for general work floors: 10 ⁸ to 10 ¹¹ Ω
In the case of the paint composition shown in the latter category, the desired leakage resistance value for the above-mentioned general work floor can be obtained, but according to practical examples, conductivity is poor under low temperature and low humidity conditions such as winter. This situation was likely to occur. The inventor of the present invention has learned the following as a result of repeated research to develop a conductive coated floor coated with a coating composition that does not have the above-mentioned drawbacks.

i.e. 20% epoxy resin, 50% conductive zinc oxide
%, paint additive 0.5%, colorant 6%, MIBK 16%,
For 3 base materials consisting of 7.5% ISO butanol,
This is an example of a coating material made of a curing agent consisting of 32.6% modified aliphatic amine and 67.4% toluene in a ratio of 1 part.The zinc oxide is dispersed into secondary particles using a dispersion device with a low shearing force such as Hyper. Sample A as a state
and Sample B, in which the zinc oxide is made into a primary particle state using a dispersion device with excellent shearing force and mixing power such as a sand mill, are applied at 0.15 kg/m ² to form a coating bed, and similarly conductive oxide Sample C, a commercially available flooring material in which zinc had been made into primary particles, was applied in the same manner to form a coated floor, and the leakage resistance values in the lateral direction and thickness direction of the coated floor were measured in September and January. Results, samples B and C
In January, which is the winter season, there was no lateral conductivity, and there was conductivity in all other areas.

In addition, the side resistance of the coated floor made from Sample B was ∞Ω when it was applied in January, but the value measured by attaching water-soaked tissue paper to the floor surface and peeling it off after 24 hours was 10 MΩ. When this was left at room temperature at 50° C. for 1 hour, the value was 25 MΩ.

Furthermore, at the same time, a painted floor piece made of the same sample B was
It was set in a closed container with water stored at the bottom, separated from water, and after being left for 24 hours, it was taken out and dried, and the measured value was 5 MΩ.

Approximate values were measured in several experimental examples similar to those described above.

Based on this, the present inventor found that in a coated floor in which conductive zinc oxide is dispersed as secondary particles, there is no problem with conductivity because the zinc oxide is connected vertically and horizontally, but when conductive zinc oxide is dispersed as primary particles. It has been found that in a coated floor, the zinc oxide, which has become a primary particle, is dispersed in a separated form that is connected in the vertical direction of the coating thickness and unconnected in the horizontal direction. At this time, the reason why it shows conductivity except during low temperature and low humidity periods such as winter, but does not show conductivity during these periods cannot be said to have been clearly elucidated, but outside of low temperature and low humidity periods, vaporization during solvent volatilization The heat lowers the coating temperature and causes condensation, and this condensation reacts with the amine, which is the curing agent for the epoxy resin, to form a conductive amine carbonate, and the conductive zinc oxide reacts with the carbonate. Therefore, they connect in the lateral direction and produce conductivity, but it is presumed that this is because the conductive zinc oxide does not connect in the lateral direction because no dew condensation occurs during periods of low temperature and low humidity.

The present invention was made based on the above knowledge, and is a general work floor that can be colored arbitrarily and is stable throughout the year, including low temperature and low humidity periods such as winter, and is specified in the electrostatic safety guidelines of the Ministry of Labor. An object of the present invention is to provide a conductive coated floor coated with a coating composition capable of obtaining a desirable leakage resistance value of 10 ⁸ to ^{10 11} Ω or less.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a paint composition containing a synthetic resin vehicle in which conductive zinc oxide is uniformly dispersed in the form of secondary particles, and a coloring agent. The substance is applied as an undercoat to the painted floor to make this undercoat conductive. In order to make this undercoat conductive, it is preferable to uniformly disperse conductive zinc oxide in the form of primary particles. The undercoat layer is coated with a coating composition containing a synthetic resin vehicle and a colorant.

(Example) An embodiment of the present invention will be described below.

Table 1 shows a paint composition using conductive zinc oxide doped with aluminum. After blending these components, conductive zinc oxide is mixed into a synthetic resin vehicle using a dispersion device with low shearing force such as Hyper. A paint composition uniformly dispersed in the form of secondary particles is applied to the base floor as an undercoat, and conductive zinc oxide is applied in the same formulation using a dispersion device with excellent shearing force and mixing power such as a sand mill. , a coating bed formed by applying a coating composition in which conductive zinc oxide is uniformly dispersed in a synthetic resin vehicle in a state in which it is uniformly loosened from secondary particles to primary particles, as a top coat, on the above-mentioned undercoat layer ( Table 2 shows the physical properties of a coating thickness of 0.15Kg/m ² ).

The conductive coated floor formed in this example exhibits a leakage resistance value of 10 ⁵ to 10 ⁷ Ω according to the electrostatic safety guidelines of the Ministry of Labor, and this resistance value is stable throughout the year and does not change during periods of low temperature and low humidity. Ta. In addition, the desired coloring was achieved clearly.

Table-1 (Total paint composition 100% by weight) (base agent) epoxy resin 20 Conductive zinc oxide 35 Color separation inhibitor 0.2 Antifoaming agent 0.1 Antisettling agent 0.2 Coloring agent 3 Methyl iributyl ketone 11 Isobutanol 5.5 (hardening agent) Modified aliphatic amine curing agent 7.0 Toluene 18 Table-2 (physical properties) Pencil hardness: 3H (after curing for 7 days at 20℃) Adhesion: 100/100 (same as above) Abrasion resistance: 0.05g, CS-17/250g 1000 revolutions, (same as above) Film curing (below 20℃) Primer: gels after 20 minutes, hardens after 3 hours Top coat: gels after 30 minutes, hardens after 6 hours Viscosity (BH rotational viscometer) Hardening agent: 60cps, 20℃, No. 2 20rpm Undercoat: 400cps, 20℃, No. 3 20rpm Top coat: 650cps, 20℃, No. 3 20rpm Conductivity: 10MΩ (NFPA method).

The synthetic resin vehicle used in the present invention includes epoxy resin, acrylic urethane resin,
Examples include acrylic resins, vinyl acetate acrylic resins, polyurethane resins, unsaturated polyester resins, vinyl chloride resins, chlorinated rubber resins, alkyd resins, acrylic resin emulsions, etc. As a coating composition, epoxy resins have excellent physical properties, It is particularly preferred because it exhibits chemical resistance. Colorants include titanium dioxide, carbon black, black iron oxide, yellow iron oxide, Bengara, chromium oxide, azo organic pigments,
Examples include color pigments used in common paints such as cyanine blue and cyanine green. The solvent for dissolving the synthetic resin vehicle may be one or two selected from organic solvents such as aliphatic or aromatic, hydrocarbon, alcohol, ether alcohol, ester, and ketone, depending on the vehicle used. Mixtures of more than one species are used. In addition, as auxiliary agents, dispersants, wetting agents, anti-settling agents,
Anti-sag agents, color separation inhibitors, leveling agents, anti-cissing agents, antifoaming agents, etc. can be added. Furthermore, in order to increase the conductivity of the paint composition, conductive substances such as graphite, conductive carbon black, metal powder, metal fiber metal flakes, carbon fiber, and other conductive substances and antistatic agents are added to the paint composition as necessary. It can be added in small amounts as long as it does not impede the physical properties or color of the product. The conductive zinc oxide of the present invention is easily and uniformly dispersed in a synthetic resin vehicle, but if necessary, dispersion can be promoted using a pigment dispersant, a titanate coupling agent, or the like.

According to the conductive coated floor of the present invention, by applying a coating composition in which conductive zinc oxide is uniformly dispersed in a synthetic resin vehicle in the form of secondary particles as an undercoat, the conductive zinc oxide The problem of non-conductivity during construction under low temperature and low humidity conditions such as winter in a paint composition in which the particles have been loosened to primary particles has been solved. In addition, by applying a paint composition in which conductive zinc oxide is uniformly dispersed in the form of primary particles as a top coat, it is possible to prevent uneven brushing and color unevenness, and the desired colored floor surface can be obtained. .

By the way, in the undercoat layer of the present invention, since the solvent evaporates after coating, zinc oxide in the form of secondary particles protrudes from the surface by the amount of meat thinning, and the coated surface of the undercoat layer becomes uneven. When the top coat layer is formed thin so that the protruding top portion is exposed on the surface, the top coat can be applied with any desired paint. This also makes it possible to obtain a desired colored floor surface and to obtain stable conductivity through the protruding top portion.

(Effects of the Invention) As described above, according to the present invention, not only can the color be arbitrarily colored to create a desirable beauty, but also be stable throughout the year, including low temperature and low humidity periods such as winter, and meet the electrostatic safety guidelines of the Ministry of Labor. It is possible to provide a conductive coated floor coated with a coating composition that can obtain a leakage resistance value of 10 ⁸ to ^{10 11} Ω or less, which is desirable for general work floors.

Claims (1)

[Scope of Claims] 1. A coating composition containing a synthetic resin vehicle in which conductive zinc oxide is uniformly dispersed in the form of secondary particles and a coloring agent is applied as an undercoat onto a base, and this undercoat layer is coated with a conductive layer. A conductive coated floor characterized by a conductive coating. 2. A coating composition containing a synthetic resin vehicle and a colorant in which conductive zinc oxide is uniformly dispersed in the form of secondary particles is applied onto the substrate as an undercoat, and the conductive zinc oxide is uniformly dispersed in the form of primary particles. 1. A conductive coated floor, characterized in that the undercoat layer is overcoated with a coating composition containing a synthetic resin vehicle and a coloring agent dispersed in the same state.