JP2002194280A - Polyester coating material and coating method therewith - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyester coating material which can sufficiently ensure the adhesion of a coating film without priming, can be applied thick without causing sagging or pinholes, and hence can reduce the coating cost while maintaining coating quality; and a coating method using the same. SOLUTION: This polyester coating material C, for coating an object material 1 having hydroxyl groups, is prepared by adding 2-30 pts.wt. polyisocyanate compound to 100 pts.wt. unsaturated polyester resin. The coating method using the polyester coating material C comprises preparing an object material 1 having hydroxyl groups, preparing an unsaturated polyester resin coating material C by adding 2-30 pts.wt. polyisocyanate compound to 100 pts.wt. unsaturated polyester resin, and coating the object material 1 with the unsaturated polyester resin coating material C by a rotary-spray-type electrostatic coating method.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyester paint for painting, for example, a side plate of a piano, and a coating method using the same.

[0002]

2. Description of the Related Art Piano side plates are conventionally coated by the following method. First, the surface of the side plate formed into a predetermined shape is polished. Next, for example, a urethane primer is applied to the surface of the side plate as an undercoat. This undercoat is good for both the side plate and the unsaturated polyester, since the unsaturated polyester resin coating applied thereon has poor adhesion to the side plate made of a wood material and has the property of easily peeling off. The above-mentioned paint having excellent adhesion is applied in advance. Next, after the undercoat film is dried, an unsaturated polyester resin paint is applied as a top coat by spray coating a plurality of times (for example, five times) at predetermined time intervals (for example, 15 minutes). The overcoating is performed in a plurality of times as described above. In the case of spray coating, it is impossible to apply a high-viscosity paint, and a low-viscosity paint of about 500 to 800 mPa · s has to be used. Because it is impossible to obtain it, it is easy for the paint to drip when it is applied thickly at one time. To do that. Another reason is that in the case of spray coating, since the particle size of the sprayed paint is non-uniform, if it is applied thickly at one time, air tends to remain in the paint film and pinholes are likely to occur. This is to avoid this.

[0003]

However, in the above-mentioned conventional coating method, in order to prevent the dripping of the paint and the occurrence of pinholes, the overcoating of the unsaturated polyester resin paint is divided into a plurality of times at time intervals. Time is required for painting, and the productivity is low. Also,
Since the top coat is applied by spray painting, the paint is easily dissipated,
Due to the low application efficiency, the amount of paint used is also high, which also causes an increase in coating costs.

Further, since it is necessary to perform undercoating, productivity is further reduced by the time required for undercoating and drying, and equipment and space for undercoating and drying are required, and equipment costs are also increased. .

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and it is possible to sufficiently secure the adhesion of a coating film without performing an undercoating, and to prevent the paint from dripping or pinholes. It is an object of the present invention to provide a polyester paint capable of reducing the coating cost while maintaining a high coating quality with an unsaturated polyester resin paint, and a coating method using the same.

[0006]

In order to achieve this object, the present invention relates to a polyester coating for coating a substrate material having a hydroxyl group, wherein the polyester coating is based on 100 parts by weight of an unsaturated polyester resin. It is characterized in that 2 to 30 parts by weight of an isocyanate compound is added.

According to this polyester coating, the coating is applied to the coating material having a hydroxyl group, whereby the hydroxyl groups in the coating material and the isocyanate groups in the coating are chemically strongly bonded to each other. The film firmly adheres to the surface of the material to be coated. Further, as described later, it has been confirmed that this adhesion can be sufficiently secured when the addition amount of the polyisocyanate compound is 2 to 30 parts by weight based on 100 parts by weight of the unsaturated polyester resin. As a result, according to the polyester paint of the present invention, it is possible to abolish the conventional undercoat, thereby reducing the coating cost by reducing the time and equipment cost for the undercoat.

In order to achieve the above object, a coating method using the polyester paint of the present invention comprises preparing a material to be coated having a hydroxyl group, and adding a polyisocyanate compound to 100 parts by weight of an unsaturated polyester resin. Up to 30 parts by weight of the added unsaturated polyester resin paint is prepared, and the material to be coated is coated with the unsaturated polyester resin paint by a rotary atomizing electrostatic coating.

According to this coating method, the unsaturated polyester resin paint (hereinafter referred to as “paint”) is applied to the material to be coated while being atomized by centrifugal force and static electricity generated by high-speed rotation by electrostatic spraying of a rotary atomization type. Therefore, it is possible to apply a thick paint using a high-viscosity paint. By doing so, since the paint has a high viscosity, no dripping of the paint occurs even when the paint is applied thickly. For the same reason, since the paint is applied in a fine and uniform particle size, air does not remain in the paint film even when thickly applied, and pinholes do not occur. in this way,
The paint can be thickly applied by, for example, only one application without causing dripping or pinholes of the paint. In addition, since the charged paint is applied to the material to be coated while being pulled, the coating efficiency is improved and the amount of paint used can be reduced as compared with spray coating.

[0010] Further, as described in claim 1, by adding 2 to 30 parts by weight of the polyisocyanate compound to the unsaturated polyester resin, the hydroxyl group in the material to be coated is applied to the coating material. The isocyanate groups in the inside are chemically bonded strongly, and the coating film adheres sufficiently to the surface of the material to be coated, so that the conventional undercoating can be eliminated. As described above, according to the present invention, it is possible to reduce the coating cost by maintaining the coating quality by performing one thick coating of the coating, reducing the amount of the coating used, and eliminating the undercoat.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the drawings. 1 and 2 schematically show a method for painting a side plate of a grand piano to which the present invention is applied, and FIG. 3 shows a cross section of the painted side plate. As shown in FIG. 3, this side plate 1 is formed by bonding a plurality of wooden laminates 2 (approximately 15 layers) of about 15 layers and decorative veneers 3 and 3 on the front and back sides in a laminated manner, and at the same time, to the outer shape of a grand piano. It is formed in a conformed shape, and a brace (not shown) is formed at the left and right front ends.
An unsaturated polyester resin paint C is applied by a coating device 6 to an outer surface, upper and lower surfaces, and an inner surface of a crosspiece of the side plate 1 to form a coating film 5.

In the present embodiment, a commercially available unsaturated polyester resin paint (hereinafter referred to as “paint”) C can be used, and a predetermined amount of a polyisocyanate compound is added to this paint C. And finally has a high viscosity (for example, 1000 to 3000 mPa · s, more preferably 1000 to 1600 mPa · s). Such a viscosity range is preferable for the following reason. That is, as described later, the coating device 6 is of an electrostatic coating type. One of the features of the electrostatic coating is that the charged atomized paint goes around the upper and lower surfaces of the side plate 1. If the viscosity is too high, the effect of the wraparound cannot be sufficiently obtained due to the large particles of the atomized paint, and is sufficiently obtained in the above-described range of 1000 to 1600 mPa · s.

As the polyisocyanate compound to be added to the coating material C, tolylene diisocyanate, xylene diisocyanate, hexamethylene diisocyanate, polymethylene polyphenyl isocyanate, triphenylmethane triisocyanate, methylene bis-diphenyl isocyanate and the like can be used. is there. Further, these polyisocyanate compounds, toluene,
Those dissolved with a solvent such as xylene, ethyl acetate, butyl acetate, methyl ethyl ketone, or methyl isobutyl ketone may be used.

The coating material C contains an appropriate amount of a curing agent, a curing accelerator and a diluent. As the curing agent, an organic peroxide such as methyl ethyl ketone peroxide or t-butyl hydroperoxide is used. The diluent used is, for example, a polymerizable monomer such as a styrene monomer.

Further, a coloring agent such as a coloring dye or a coloring pigment, an extender such as calcium carbonate or talc, a wax, a surfactant or a leveling agent, which are commonly used in the art, are added to the coating material C. May be.

As shown in FIG. 1, the coating apparatus 6 includes a robot 7 having a movable arm 7a, and an electrostatic coating machine 8 attached to the tip of the arm 7a. The robot 7 moves the electrostatic coating machine 8 three-dimensionally via the arm 7a and controls the position thereof. The electrostatic coating machine 8 is of a rotary atomization type bell type, and has a bell 8 provided at the tip end.
a rotates at a very high speed, and when the paint C transmitted on the inner wall of the bell 8a jumps out due to centrifugal force, the paint C
Is charged and atomized. According to this method,
A coating material having a high viscosity, for example, about 1000 to 3000 mPa · s can be applied in a fine and uniform particle size.

Next, a method of coating the side plate 1 will be described with reference to FIGS. First, the side plate 1 formed in a predetermined shape is placed on a turntable 9 in a coating room via a pair of receiving jigs 10 and 10. These receiving jigs 10 are made of, for example, aluminum, are grounded, and also serve as ground electrodes. Next, while rotating the turntable 9 slowly and moving the electrostatic coating machine 8 to a desired position by the robot 7, the bell 8a is rotated at a very high speed, so that the paint C is charged and atomized. Spray toward the outer surface of 1.

As a result, the paint C is applied to the outer side surface while being pulled toward the side plate 1 by the static electricity. Also,
Part of the paint C is applied to the upper and lower surfaces of the side plate 1 so as to be applied. When the paint C adheres to the side plate 1, the electric charge of the paint C is discharged via the receiving jig 10. Then, by continuing the spraying of the paint C, the side plate 1 is thickly applied by the electrostatic coating, whereby the coating film 5 of the paint C is formed.

As described above, according to the coating method of this embodiment, the side plate 1 is atomized by the rotary atomizing type electrostatic coating machine 8 while the paint C is atomized by the centrifugal force and the static electricity caused by the ultra-high speed rotation of the bell 8a. , It is possible to make a thick coating using the high-viscosity paint C, and by doing so, the paint C
Has a high viscosity, so that the paint C does not sag even when it is thickly applied. In addition, since the coating material C is applied in a fine and uniform particle size, even if the coating material is thickly applied, no air remains in the coating film 5 and no pinholes occur. As described above, the coating material C can be thickly applied only by one application without causing the coating material C to sag or pinhole. Also, since the charged paint C is applied to the side plate 1 while being drawn,
The coating efficiency is improved as compared with spray coating, and the amount of paint used can be reduced.

Further, as described above, since the polyisocyanate compound is added to the paint C, the hydroxyl groups in the side plate 1 made of wood and the isocyanate groups in the applied paint C are chemically and strongly bonded. By doing so, the coating film 5 sufficiently adheres to the surface of the side plate 1. As a result, as described above, the conventional undercoat can be eliminated, thereby reducing the time and equipment cost for the undercoat. As described above, according to the present embodiment, it is possible to greatly reduce the coating cost by maintaining the coating quality by performing one thick coating of the coating C, reducing the amount of the coating used, and eliminating the undercoating.

The following Table 1 shows the results of tests conducted to confirm the effect of improving the adhesion of the coating film 5 by the above-mentioned polyisocyanate compound. In this test, as examples, six samples BG in which the addition amount of the polyisocyanate compound was different from each other in the range of 1 to 50 parts by weight with respect to 100 parts by weight of the unsaturated polyester resin, and a comparative example was prepared. As a sample, a sample A to which no polyisocyanate compound was added was prepared, and a peeling test was performed on each sample. Note that appropriate amounts of the curing agent, the curing accelerator, and the diluent were added.

[0022]

[Table 1]

As shown in Table 1, when no polyisocyanate compound was added (Sample A), the coating 5
Was insufficient in adhesion, and a clear peeling phenomenon was observed.
When the addition amount was 0.5 to 1.5 parts by weight (samples B and C), the adhesion was not perfect, and a partial peeling phenomenon was observed. On the other hand, when the addition amount of the polyisocyanate compound was 2 to 30 parts by weight (samples D to G), no peeling phenomenon was observed at all, and it was confirmed that sufficient adhesion could be ensured. However, if the added amount exceeds 10 parts by weight, the cost is increased. Therefore, it is understood that the added amount of the polyisocyanate compound is most preferably 2 to 10 parts by weight based on 100 parts by weight of the unsaturated polyester resin.

The present invention is not limited to the embodiments described above, but can be implemented in various modes.
For example, the embodiment is an example in which the present invention is applied to the painting of a side plate of a grand piano, but the present invention is not limited to this and can be widely applied. Specifically, the material to be coated may be any material having a hydroxyl group with which an isocyanate group reacts, for example, a woody material, a woody material, a woody material such as a hard board or a particle board, a decorative paper,
Paper materials such as resin-impregnated paper and resin-impregnated paper laminates, phenolic resins, ABS resins, and plastic materials such as melamine-coated boards and polyester-coated boards are exemplified. Further, the application of the present invention is not limited to pianos, but can be applied to a wide range of fields such as furniture and building materials. In addition, it is possible to appropriately change the detailed configuration and the like within the scope of the present invention.

[0025]

As described in detail above, the polyester coating of the present invention and the coating method using the same can sufficiently secure the adhesion of the coating film without performing the undercoating, and can prevent dripping of the coating and pinholes. Without causing such an effect, the unsaturated polyester resin paint can be applied thickly, which has an effect that the coating cost can be reduced while maintaining the coating quality.

[Brief description of the drawings]

FIG. 1 is a view showing a method for coating a side plate of a grand piano according to an embodiment of the present invention.

FIG. 2 is a view showing a coating situation in the coating method of FIG. 1;

FIG. 3 is a sectional view of a painted side plate.

[Description of Signs] 1 Side plate (material to be coated) 5 Coating film 6 Coating device 8 Electrostatic coating machine C Unsaturated polyester resin paint

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) C09D 167/06 C09D 167/06 F term (Reference) 4D075 AA10 DA23 DC38 EB35 4F033 PB16 4F034 AA04 BA22 4J038 DG221 DG271 DG281 PA03

Claims (2)

[Claims] 1. A polyester paint for coating an object material having a hydroxyl group, wherein 2 to 30 parts by weight of a polyisocyanate compound is added to 100 parts by weight of an unsaturated polyester resin. Characteristic polyester paint. 2. A coating material having a hydroxyl group is prepared, and an unsaturated polyester resin paint is prepared by adding 2 to 30 parts by weight of a polyisocyanate compound to 100 parts by weight of an unsaturated polyester resin. A coating method using a polyester paint, wherein the material is coated with the unsaturated polyester resin paint by a rotary atomization type electrostatic coating.