JP2017101194A - Retroreflective coating, coated film and substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coating good in coatability without causing unevenness during retroreflection, a coated film and a substrate.SOLUTION: There is provided a retroreflective coating containing a retroreflective glass bead of which at least a part of surface is coated by a reflective film, an aqueous synthetic resin and water, wherein the retroreflective glass bead has specific gravity of 2 or more, average particle diameter of 10 μm or more and viscosity of the retroreflective coating Vand viscosity parameter TI satisfying following relational expressions (1) to (3) at same time. V≥500 mPa s (1) TI≤0.74 (2) TI≥0.2 log(V)-0.45 (3), where Vrepresents viscosity (mPa s) measured under a condition with rotor rotation number of 20 rotations/min. by a BH shaped rotation viscometer, TI represents viscosity parameter defined by TI=log(V/V) and Vrepresents viscosity (mPa s) measured under a condition with rotor rotation number of 2 rotations/min. by the BH shaped rotation viscometer.SELECTED DRAWING: None

Description

  The present invention relates to a retroreflective coating material, a coating film, and a substrate.

  Conventionally, in order to improve visibility in the dark, retroreflectivity that reflects light incident from the outside in the same direction as the incident direction is used, for example, by efficiently reflecting the headlight of an automobile toward the driver. Awareness is being made. And as what gives such retroreflective property, the coating material etc. which combined the coating material containing a self-reflection bead, a glass bead, and a reflecting material with transparent resin are proposed (for example, patent documents 1-3 etc.). .

JP 2011-206655 A JP 2013-85995 A JP 2010-254884 A

However, if there is a relatively large solid substance such as glass beads having a specific gravity of 2 or more in the paint and a particle size of 10 μm or more, the beads settle in the paint and are homogeneous. Can not be obtained. Therefore, the coating using such a coating becomes complicated, that is, the workability is poor and the coating property is lowered. In addition, even with paints that have taken measures to prevent the beads from settling, a paint film made of such a solid substance having a large particle size cannot obtain a uniform paint film, which causes unevenness during retroreflection. Often occurs.
Accordingly, there is a demand for a coating material that has good coating properties, can be applied easily, and does not cause unevenness in re-reflection on the coating film.
The present invention has been made in view of the above problems, and an object of the present invention is to provide a coating material, a coating film, and a substrate that have good coating properties and do not cause unevenness during retroreflection.

  The inventors of the present application are eager about the relationship between the retroreflectivity of the coating film and the viscosity and thixotropy of the paint containing the retroreflective glass beads in consideration of coating properties including workability and work efficiency. I did research. That is, if the viscosity of the paint is low, the glass beads tend to settle in the paint, and the paint cannot maintain homogeneity. At the same time, if the thixotropy is low, the glass beads tend to settle, and if the thixotropy is high, the glass beads are difficult to settle. The settling of glass beads in the paint reduces the homogeneity of the paint, not only significantly lowers the workability and work efficiency of the coating, but also causes uneven coating, resulting in a reduction in retroreflectivity. To do. On the other hand, if the viscosity is high and the thixotropy is high, the glass beads are less likely to settle, but the coating properties may also be reduced, particularly causing a reduction in work efficiency, and at the same time the uniformity of the coating film is reduced. Retroreflectivity is reduced. Therefore, it is important to balance the coating property, viscosity, and thixotropy as requirements for improving the coating property and satisfying the retroreflectivity of the coating film. In addition to these findings, the present inventors have found that the paint satisfying a specific relationship with respect to viscosity and thixotropy is excellent in the uniformity of the coating film and improves the reflection luminance, thereby completing the present invention.

The present application provides the following inventions.
A retroreflective coating comprising retroreflective glass beads, a water-based synthetic resin, and water at least partially coated with a reflective film,
The retroreflective glass beads have a specific gravity of 2 or more and an average particle size of 10 μm or more.
Retroreflective coatings and satisfies the viscosity V ₂₀ and viscosity parameter TI has the following relationship of the retroreflective coating (1) to (3) simultaneously.
V ₂₀ ≧ 500 mPa · s (1)
TI ≦ 0.74 (2)
TI ≧ 0.2 · log ₁₀ (V ₂₀ ) −0.45 (3)
[In formula (1)-(3),
V ₂₀ is a BH type rotary viscometer, the viscosity of the rotor speed is measured at a 20 rotation / min (unit: mPa · s),
TI is a viscosity parameter defined by TI = log ₁₀ (V ₂₀ / V ₂ ),
V ₂ represents a viscosity (unit: mPa · s) measured with a BH type rotational viscometer under the condition that the rotor rotational speed is 2 revolutions / minute. ]
This retroreflective coating preferably includes one or more of the following.
The aqueous synthetic resin is a silicon acrylic resin.
The retroreflective glass beads have a bead particle size of 25 to 100 μm.
The weight ratio of the retroreflective glass beads and the aqueous synthetic resin is 1: 0.1 to 1.0 (nonvolatile content ratio).
Retroreflective paint for roller coating.
The coating film formed with the retroreflective coating material mentioned above, and a base material provided with this coating film.

  The retroreflective coating material of the present invention has excellent stability and good coatability. Therefore, in the coating film using this retroreflective coating, it is possible to effectively avoid the occurrence of uneven reflection during retroreflection.

It is a graph which shows the relationship between the viscosity of a reflective paint, and reflective brightness | luminance.

[Retroreflective paint]
The retroreflective coating material in the present invention (hereinafter sometimes referred to as “paint”) includes glass beads, an aqueous synthetic resin, and water. And this coating material satisfy | fills the specific relational expressions (1)-(3) mentioned later simultaneously in a viscosity and a viscosity parameter.

  Such a paint can be suitably used for applications where visibility is particularly required in consideration of safety. For example, guards for road shoulders, median strips, road signs, guard rails, guard pipes, fences and other protective fences, bolts, nuts, caps, brackets, columns, base plates, wire cables, beams, pipes, screen panels, etc. There are various uses such as components of fences, exteriors of automobiles (bumpers and doors), exteriors of trains, fuselage and wings of aircraft, helicopter propellers, windmill wings, and ship exteriors. Such a paint can facilitate the visibility of the positions of curbstones, median strips, guardrails, vehicles, various members, etc. even in the dark, such as at night, by using a light source such as a vehicle headlamp.

(Glass beads)
The glass beads have retroreflectivity at least part of which is coated with a reflective film.
Here, the retroreflective property is a generally recognized characteristic, and is a reflection phenomenon in which incident light returns to the incident direction again by a special optical reflection mechanism, and is a mirror in which the incident angle and the reflection angle are equal. Unlike reflection, this means that the received light is reflected back to the light source.
In order to impart retroreflectivity to the glass beads, at least a part of the surface of the glass beads is coated with a reflective film.

As the glass beads themselves, any of those used in the art can be used. Examples of the glass component include those containing silicon dioxide, barium oxide, titanium dioxide, barium titanate and the like. The average particle diameter of the glass beads is 10 μm or more, for example, about 10 to 200 μm, preferably about 25 to 100 μm, and more preferably about 40 to 50 μm. By setting it as such a range, while being able to maintain the dispersion state in a coating material, desired retroreflection performance can be exhibited. The average particle size can be measured by a sieving method.
For example, the glass beads preferably have a specific gravity of 2 or more, more preferably 3 or more, and still more preferably 4 or more.

The reflective film covering the surface of the glass beads means a film made of a material capable of reflecting 50% or more of received light, preferably a film made of a material capable of reflecting 60% or more, more preferably 70% or more. To do. For example, the film | membrane with metals, such as aluminum, silver, nickel, tin, zinc, these alloys, or an oxide is mentioned. Among these, aluminum is preferable because it is inexpensive and hardly deteriorates.
The degree of coating with the reflective film is preferably about 30 to 70%, and more preferably about 40 to 60%, from the viewpoint of balancing both the incidence and reflection of light on the glass beads.

  Glass beads having at least a part of the surface coated with a reflective film can be produced by a known method such as the method described in JP2011-206655A, or a commercially available product can also be used. .

(Water-based synthetic resin)
The aqueous synthetic resin is preferably an aqueous dispersion resin. Aqueous synthetic resins include acrylic silicon resin, acrylic resin, urethane resin, polyolefin, polyvinyl acetate, vinyl acetate copolymer, polystyrene, styrene copolymer, polyester resin, polyester-alkyd resin, alkyd resin, phenol resin. , Urethane silicone resin, epoxy resin and the like. Of these, acrylic silicon resin, acrylic resin, urethane resin, polyolefin, polyvinyl acetate, vinyl acetate copolymer, polystyrene, styrene copolymer and the like are preferable. Moreover, a water-soluble resin may be sufficient and these may coexist.
In the paint of this application, you may contain fats and oils and an organic solvent as a medium of a paint.

(paint)
The mixing ratio (mass ratio) of each component in the paint is preferably 1: 0.1 to 1.0, preferably 1: 0.2 to 0.5, with glass beads: aqueous synthetic resin being a non-volatile content ratio. Further preferred. Moreover, about the ratio of the glass bead and the water contained in a system, glass beads: water is preferable 1: 0.1-5.0, and 1: 0.2-1.0 is further more preferable.
When the ratio of the glass beads is too large or the particle size is too small, the thixotropic property of the coating is increased, the uniformity of the coating film is lowered, and the retroreflective brightness is lowered. Moreover, when the ratio of the glass beads is too high, the glass beads are easily detached from the coating film.

In the paint having such a composition, the viscosity (V ₂₀ ) and the viscosity parameter (TI) simultaneously satisfy the following relational expressions (1) to (3).
V ₂₀ ≧ 500 mPa · s (1)
TI ≦ 0.74 (2)
TI ≧ 0.2 · log ₁₀ (V ₂₀ ) −0.45 (3)
In the formulas (1) to (3), V ₂₀ is a viscosity (unit: mPa · s) measured with a BH type rotational viscometer at a rotor rotational speed of 20 revolutions / minute, and the liquid temperature of the paint is A temperature of 25 ° C. is preferable.
TI is a viscosity parameter defined by TI = log ₁₀ (V ₂₀ / V ₂ ).
V ₂ is a viscosity (unit: mPa · s) measured with a BH type rotational viscometer at a rotor rotational speed of 2 revolutions / minute, and the liquid temperature of the paint is preferably 25 ° C.

For example, even if the thixotropy is high, if the viscosity is low, the roller slides during coating, and the glass beads gather near the corner of the coated surface as if rubbed with a spatula, and the coating film cannot be uniformly finished.
From such a viewpoint, by satisfying all of (1) to (3), the coating property becomes good, a uniform coating film can be obtained, the unevenness of the retroreflective performance is eliminated, and the retroreflective performance is improved. This can be further improved.
From another viewpoint, the viscosity V ₂ is preferably 1000 mPa · s or more.

Viscosity in the paint, that is, V ₂₀ and V ₂ are adjusted by appropriately adjusting the type and amount of the water-based synthetic resin, the amount of water, the type and amount of the viscosity adjusting agent described later, and the amount and size of the glass beads. can do.
TI can be adjusted, for example, by appropriately adjusting the type and amount of a viscosity adjusting agent described later.

  The paint may contain additives known in the art in order to impart various functions. For example, cross-linking agents, viscosity modifiers / thickeners, water repellents, oil repellents, pigments, uncoated glass beads, dispersants, etc., as long as they do not affect the stability of the paint, such as sedimentation, aggregation, solidification, etc. Can be contained.

The crosslinking agent can be added to improve the strength of the coating film, heat resistance, and weather resistance. For example, cross-linking agents such as isocyanate-based, carbodiimide-based, oxazoline-based, and silane coupling agent-based are listed.
Viscosity modifiers / thickeners can be added to adjust the viscosity. For example, Bennite-based, ultrafine silica-based, silicate-based inorganic viscosity modifier / thickener, polyamide wax, urethane-modified polyether, polyacrylic acid, acrylic acid copolymer, Examples thereof include organic viscosity modifiers and thickeners such as acrylate copolymer, fiber derivative, polyethylene oxide, thickening polysaccharide, and polyvinyl alcohol. Of these, those of alginic acid type, polyacrylic acid type and fiber derivative type are preferable.
A water repellent may be added to impart water repellency. For example, a fluorine-type water repellent, a silicon-type water repellent, a paraffin-type water repellent, etc. are mentioned.

An oil repellent may be added to impart oil repellency. For example, a fluorine-type oil repellent is mentioned.
Pigments may be added to color the paint. Examples thereof include organic pigments, inorganic pigments such as carbon black and titanium oxide, extender pigments such as minerals, and metal powders.
Uncoated glass beads may be added to provide reflective performance other than retroreflection. Examples of the uncoated glass beads include the same size and shape as the glass beads coated with the above-described reflective film.
A dispersant can be added to improve the dispersion stability of retroreflective glass beads and other dispersible additives. Examples thereof include anionic, cationic, nonionic, and amphoteric surfactants.

  The paint may be mixed by simultaneously adding glass beads, aqueous synthetic resin, and water, or by adding glass beads and aqueous synthetic resin dispersed in water, and then adding water and mixing. May be. These mixings can be performed using a paint shaker or the like used for mixing ordinary paints.

(Coating film and substrate)
The coating film is formed by applying the above-described retroreflective coating material to an object to be coated.
The coating method here is, for example, an air spray method, an air atomizing electrostatic coating method, an airless electrostatic coating method, a direct coating method using a brush or a roller, a screen printing method, a gravure roll coating, a reverse roll. Known methods such as coating, wire bar coating, lip coating, air knife coating, curtain flow coating, dip coating and the like can be mentioned. Especially, the direct coating method by a brush, a roller, etc. is preferable, and the direct coating method by a roller is more preferable. Because it contains glass beads and is adjusted to a viscosity and TI that uniformly disperse the glass beads, it may cause defects (nozzle clogging, etc.) in the process when atomization is performed. It is. Moreover, it is because it is preferable that it is a construction method which is hard to receive influence of strong wind, rain, etc. in the coating by the outdoors. Furthermore, when it is expected that coating is performed over a wide range, a simple selection of the coating method is suitable.

  For example, when using the direct coating method with a roller, a coating material is applied to a base material with a roller, and a coating film is left still and dried. This step may be performed a plurality of times, but is preferably performed only once. This is for ensuring the uniformity of the coating film and obtaining good reflection luminance.

The thickness of the coating film can be appropriately adjusted depending on the application, the type of paint component, the type of article to be coated, and the like. Moreover, about 100-500 g / m < ² > is mentioned for the coating amount. If the thickness of the coating film is too thin, the coating state may be sparse and the reflection luminance may decrease, and if it is too thick, the coating may not extend uniformly and the radiance may also decrease.
Examples of the form of the coating film include a plate shape, a film shape, a sheet shape, and a tape shape.

The drying time after coating or the drying time between repeated coatings is preferably several hours or more, more preferably 4 hours or more. Drying may be non-thermal drying such as natural drying or air drying, or can be performed by hot drying such as spraying with hot air or drying using an infrared or far-infrared heater. Among them, non-thermal drying such as natural drying and air drying. As for drying temperature, about 5 to 40 degreeC is mentioned, for example. This is to ensure the uniformity of the coating film by appropriate progress of drying.
When coating outdoors, it is preferable to avoid it when it rains. This is because drying may be extremely delayed, resulting in poor film formation.

  Examples of the object to be coated with the paint, that is, the base material include various materials such as concrete, mortar, slate, wood, metal, ceramics, plastic, fiber base material, and composites thereof.

Below, the retroreflective coating material of this invention, etc. are concretely demonstrated by an Example.
Example 1
Commercially available water-based silicone acrylic emulsion (non-volatile content 45%, viscosity 580 mPa · s, pH 8.8, average particle size 0.1 μm, methyl methacrylate, cyclohexyl methacrylate, silicone modified resin emulsion of acrylic acid ester copolymer, glass Transition temperature: 26 ° C., number average molecular weight Mn: 51,700, weight average molecular weight Mw; 129,300), mass ratio of 1; Then, water was added at a mass ratio of 0.08, and the mixture was stirred and mixed at 200 rpm for 15 minutes using a 3 propeller stirring blade having a diameter of 3 cm to obtain an aqueous silicon acrylic resin dispersion A having a nonvolatile content of 41.5%. (The non-volatile content was measured using JIS K6828, the viscosity was BL-type viscometer manufactured by Tokimec, the pH was measured using a pH meter HM-30G manufactured by Toa Denpa Kogyo, and the average particle size was measured using LA-950V2 manufactured by Horiba, Ltd.)
As shown in Table 1, this water-based silicon acrylic resin dispersion A mass ratio of 0.5 (converted to non-volatile content: 0.21) is added to the retroreflective glass bead mass ratio of 1, and 3 sheets with a diameter of 3 cm A retroreflective coating was prepared by stirring and mixing at 200 rpm for 15 minutes using a propeller stirring blade.
The obtained paint was allowed to stand in a water bath at 25 ° C. for 3 hours.
About the coating material after stationary, the viscosity was measured at 25 degreeC with the Tokimec BH type rotational viscometer.
As a result, as shown in Table 2, the viscosity V ₂ (rotor rotation speed: 2 rotations / minute) was 58,800 mPa · s, and the viscosity V ₂₀ (viscosity at 20 rotations / minute) was 15,240 mPa · s. Results were obtained.

Further, from these values, the TI value was calculated by the following formula, and the relationship between V ₂₀ and the TI value is shown in FIG.
TI = log ₁₀ (V ₂₀ / V ₂ )

From these results, it was evaluated whether or not the paint obtained in this example satisfies the relational expressions (1) to (3) at the same time. In Table 2, what satisfy | fills all of these (1)-(3) was shown by the round, and the thing which does not meet 1 or more was represented by X.
V ₂₀ ≧ 500 mPa · s (1)
TI ≦ 0.74 (2)
TI ≧ 0.2 · log ₁₀ (V ₂₀ ) −0.45 (3)
[In formula (1)-(3),
V ₂₀ is a BH type rotary viscometer, the viscosity of the rotor speed is measured at a 20 rotation / min (unit: mPa · s),
TI is a viscosity parameter defined by TI = log ₁₀ (V ₂₀ / V ₂ ),
V ₂ represents a viscosity (unit: mPa · s) measured with a BH type rotational viscometer under the condition that the rotor rotational speed is 2 revolutions / minute. ]

The obtained paint was applied with a roller onto a slate substrate placed horizontally and vertically. The coating amount was 400 g / m ² . Then, it left still at room temperature for 24 hours, it was made to dry and the coating film by a retroreflective coating was obtained. Not only on the substrate placed horizontally but also on the substrate placed vertically, the peripheral contamination such as dripping did not occur, and good workability was exhibited. Moreover, the paint maintained homogeneity, and no difficulty was found in coating with a roller.

  With respect to the obtained coating film, LED light (Ultra Eco LED light S-8000 manufactured by Aliz Co., Ltd.) was irradiated from the line of sight as the reflection target position, and the reflection luminance of the coating film was visually evaluated. As a result, as shown in Table 2, uniform retroreflectivity was confirmed throughout the coating film.

Examples 2-7
Each of the components shown in Table 1 was added in the order of retroreflective glass beads, resin dispersion A, water and thickener, and then stirred for 15 minutes to prepare a paint.

In Table 1, the total amount of water indicates the total amount of water (addition amount) and water contained in the resin dispersion.
In the thickener type, SN615 is SN thickener 615 (manufactured by San Nopco),
SN623N is SN thickener 623N (San Nopco)
B-300K indicates Aaron B-300K (manufactured by Toa Gosei Co., Ltd.).
Table 2 shows the results of paint viscosity and reflection luminance uniformity.
In the evaluation column, the case where the paint viscosity satisfies the formulas (1), (2) and (3) is indicated as “O”, otherwise “X” is indicated.

The paint, coating film and base material of the present invention are required to have good coatability and need to avoid unevenness at the time of retroreflection, in particular, road shoulder curbs, median strips, road signs, guardrails, etc. Protective fences such as guard pipes and fences, bolts, nuts, caps, brackets, columns, base plates, wire cables, beams, pipes, screen panels and other protective fence components, automobile exteriors (bumpers and doors), train It can be used for exteriors, aircraft fuselage and wings, helicopter propellers, windmill wings, ship exteriors, and the like.

Claims (7)

A retroreflective coating comprising retroreflective glass beads, a water-based synthetic resin, and water at least partially coated with a reflective film,
The retroreflective glass beads have a specific gravity of 2 or more and an average particle size of 10 μm or more.
Retroreflective coatings and satisfies the viscosity V ₂₀ and viscosity parameter TI has the following relationship of the retroreflective coating (1) to (3) simultaneously.
V ₂₀ ≧ 500 mPa · s (1)
TI ≦ 0.74 (2)
TI ≧ 0.2 · log ₁₀ (V ₂₀ ) −0.45 (3)
[In formula (1)-(3),
V ₂₀ is a BH type rotary viscometer, the viscosity of the rotor speed is measured at a 20 rotation / min (unit: mPa · s),
TI is a viscosity parameter defined by TI = log ₁₀ (V ₂₀ / V ₂ ),
V ₂ represents a viscosity (unit: mPa · s) measured with a BH type rotational viscometer under the condition that the rotor rotational speed is 2 revolutions / minute. ]   The retroreflective coating material according to claim 1, wherein the aqueous synthetic resin is a silicon acrylic resin.   The retroreflective coating material according to claim 1 or 2, wherein the retroreflective glass beads have an average particle size of 25 to 100 µm.   The retroreflective coating material according to any one of claims 1 to 3, wherein a weight ratio between the retroreflective glass beads and the aqueous synthetic resin is 1: 0.1 to 1.0 (nonvolatile content ratio).   It is a retroreflective coating material for roller coating, The retroreflective coating material as described in any one of Claims 1-4.   The coating film formed with the retroreflective coating material as described in any one of Claims 1-5.   A base material comprising the coating film according to claim 6.