JPH0252073A - Formation of film on porous body - Google Patents

Abstract

PURPOSE:To form a film of high function having a uniform and smooth surface on a porous body without using a large amount of a solvent by a method wherein the porous body is coated at first with paint for a sealing layer containing a highly volatile solvent and a film forming solid and subsequently coated with paint for a surface layer. CONSTITUTION:Paint for a sealing layer prepared by dissolving a film forming solid in a highly volatile solvent is sprayed to a porous body such as polyurethane foam at first. A part of said paint penetrates into many pores of the porous body to close the same and a porous surface undeveloped state is formed on the surface of the porous body in a ratio of 10-60g/m<2>. Thereafter, a paint for a surface layer is applied to the sealing layer in a single or more layer. By this method, a uniform and smooth film can be formed to the porous body and the consumption of the paint for the sealing layer can be relatively reduced.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a porous material such as polyurethane foam that has a uniform, smooth and highly functional surface that does not reveal its porous surface condition. The present invention relates to a method of forming a coating film having the following properties.

[Conventional technology]

Conventionally, for the purpose of forming a coating film on a synthetic resin foam such as polyurethane foam, various types of paints or coating materials have been applied to the foam by brushing, soaking, roller coating, spray painting, etc. Attempts have been made to coat it.

However, even if paint or coating agents are applied to the foam by any of the above methods, the paint or coating agent usually gets into the cells of the foam and the condition of the surface of the foam is exposed as it is. It is difficult to form a uniform, smooth coating film on which the surface condition of the foam is not exposed.

In contrast, by using a special paint made by dissolving linear polyurethane in a large amount of highly volatile solvent and spraying it onto the foam while maintaining a predetermined distance, a coating film is formed on the foam. It is proposed that
(See Publication No. 47214). According to this method, by the time the paint reaches and comes into contact with the synthetic resin foam, most of the solvent has already volatilized and scattered, and solid matter has precipitated in the paint. Since the paint is sprayed onto the foam in a state where it appears to be randomly assembled, a coating film is formed without the paint entering into the cells of the synthetic resin foam.

[Problem to be solved by the invention]

However, when forming a coating film on a synthetic resin foam by the method described in Japanese Patent Publication No. 56-47214 mentioned above,
There are problems as shown below.

■ The first point is a work problem.

That is, the paint used in the above method contains a large amount of solvent, which is volatilized during painting, which is not desirable in terms of the impact on the human body and the risk of fire during one operation, and it is also expensive. It's also expensive.

In addition, since the base of the coating film is linear polyurethane, it has not only general strength such as elongation and tensile strength, but also solvent resistance, chemical resistance, weather resistance, abrasion resistance, and airtightness. , physical properties such as watertightness are not necessarily good.

(2) Furthermore, the adhesion or adhesion strength between the coating film and the synthetic resin foam is insufficient, and therefore the coating film is easily separated from the foam.

The present invention was made in view of the above circumstances, and the above-mentioned
To provide a method for solving the problems of ~■ and forming a coating film with a uniform and smooth surface and high functionality on a porous body such as polyurethane foam with good adhesiveness without using a large amount of solvent. With the goal.

[Means and effects for solving the problem] In order to achieve the above object, the method of forming a coating film on a porous body of the present invention uses a porous body as an object to be coated, and a highly volatile solvent is applied on the object to be coated. A sealing layer phase paint containing a coating film-forming solid content dissolved in the solvent is sprayed, and a part of the sealing layer penetrates into the pores of the object to be coated to close these pores. After forming porous surfaces on the surface of the object at a rate of 10 to 60 g/rd in a non-exposed state, one or more layers of surface layer paint are applied on the sealing layer.

In the present invention, the above-mentioned sealing layer phase paint is first sprayed onto a porous body. By spraying this paint from a position a predetermined distance from the porous body, the paint is sprayed before reaching the porous body. Most of the highly volatile solvent is volatilized, and the solid content is applied to the porous material in a state in which thin fibers like spider threads are entangled.In this case, the above intervals are set appropriately, and some By blocking the pores while digging into the pores, a coating film, that is, a sealing layer, is formed on the porous body by the sealing layer phase paint. Then, a surface layer paint is applied on the sealant M, but the porous openings of the porous body are covered with a sealant, and the sealant layer is coated on the surface of the porous body for 10 minutes. ~60g/rr? Since the porous surface is formed in a non-exposed state at a ratio of A uniform and smooth coating film consisting of a filler and a surface layer is formed on top. In this case, 1 in the present invention,
The solid content of the sealing layer is 10 to 60 g/r+ (to form it as thin as possible, reducing the amount of sealing layer paint used,
It is possible to reduce the amount of solvent volatilization, and therefore it is possible to solve the problems during the above work, and
Costs can be reduced. In addition, by using surface paints that have physical properties that suit the purpose,
A highly functional coating film can be formed on the porous body.6 Furthermore, as will be described later, before spraying the sealing layer phase paint, it is necessary to make sure that the regular paint is sufficiently penetrated into the pores of the porous body. When coating or spraying a sealing layer phase paint, first spray the sealing layer phase paint close to the porous body, and after this sealing layer phase paint has penetrated more fully into the pores, By spraying the sealing layer paint from the above-mentioned predetermined position to form a paint layer on the surface of the porous body that more reliably penetrates into the pores, the adhesion or adhesion strength between the porous body and the paint film is increased. Is possible.

The present invention will be explained in more detail below.

As described above, the present invention first contains a highly volatile solvent and a coating film-forming solid content, and when sprayed from a predetermined distance apart, most or almost all of the solvent evaporates during spraying, Most of the time, only the solid content reaches the porous body to be coated, and the solid content is sprayed onto the porous body in a spider web-like or intertwined state of fibers. By spray coating, a portion of this filler-required paint penetrates into the pores of the porous body and closes the pores, resulting in a coating weight of 10 to 60 g/rr? A sealing layer is formed on the surface of the porous surface in a state where the solid content is not exposed.

In this case, there is no limitation on the type of porous body, and the present invention can be applied to all kinds of porous bodies, but it is particularly suitably applied to synthetic resin foams, especially soft, semi-rigid, or rigid polyurethane foams. .

In addition, it is desirable to use a foam with a relatively fine cell count of 30 cells/inch or more, preferably 40 cells/inch or more, and a material with low air permeability. Since the bubble openings can be filled with the required paint, the amount of the filler required paint can be reduced, and therefore the objectives of the present invention in terms of work environment, cost, etc. can be more effectively achieved. Can be done.

In addition, any paint that has the above-mentioned properties may be used as the paint that requires sealing, for example, about 8 to 12%
The urethane-based paint described in Japanese Patent Publication No. 56-47214, which consists of linear polyurethane (wt%, same hereinafter), about 50% low-boiling ester, about 8-12% ketone, and about 30% chlorinated hydrocarbon, etc. can be used. By spraying these paints onto the porous body from a predetermined distance away, most of the highly volatile solvent has evaporated by the time it reaches the porous body, and thin fibers become randomly entangled. The solid content is applied onto the foam in such a state, and a portion of the solid content enters and bites into the pores, thereby closing the pores.

In addition, as mentioned above, the sealing layer is formed to have an amount of 10 to 60 g/I, but a more preferable amount is 20 to 60 g/I.
It is 40g/g. 10g/rr? If it is less than 60 g/rri, it will not function as a sealing layer, and if it is more than 60 g/rri, the amount of solvent volatilization will increase, making it impossible to achieve the object of the present invention.

In addition, as a means to increase the aging strength of the coating film on the porous body, for example, before spraying the sealing layer paint, a small amount of ordinary paint such as urethane paint is sprayed onto the porous body. However, there is a method in which this paint is soaked into the pores and then sprayed for sealing, or when spraying a paint that requires sealing, the distance between the porous body and the spray device is initially sealed. Spray the paint at a close enough distance that the solvent in the paint will hardly volatilize during spraying, allow a small amount of this paint to seep into the pores, and then adjust the distance between the porous body and the spray device to the above level. It is possible to adopt a method of spraying the paint at a distance where the solvent can sufficiently volatilize.

In the present invention, one or more surface layer paints are then applied on the sealing layer.

Here, there is no particular limitation on the type of paint for the first surface layer, and it can be selected as appropriate depending on the intended use of the porous body.

Urethane type with high physical properties 1, such as solvent resistance, chemical resistance, high strength, abrasion resistance, airtightness, watertightness, etc.

By applying at least one type of paint such as acrylic paint or vinyl chloride paint, a coating film with a uniform and smooth surface, high physical properties, and high functionality can be obtained. In this case, as the paint for the first surface layer, two-component urethane is used because it has good adhesion and adhesion to the sealing layer when a urethane paint is used as the coating required for sealing, and has high physical properties in all aspects. Particular preference is given to using paint.

Further, the coating amount of the paint for one surface layer can be freely selected depending on the use, purpose, etc. However, if the amount of coating is increased, the physical properties of the film will improve, but the cost will increase accordingly, and if the amount of coating is increased too much, the inherent properties of the porous body, such as cushioning properties in the case of flexible polyurethane foam, may be impaired. There is.

Furthermore, there are no limitations to the method of applying the surface layer paint, and appropriate methods such as brushing, dipping, roller coating, spray coating, etc. may be adopted; however, if the surface to be coated is non-flat and has a complex shape, In addition, when imparting light resistance to the surface layer, it is preferable to use a non-yellowing urethane paint (using aliphatic isocyanate) as the paint for the surface layer. It's expensive. In this case, if you first apply a regular urethane paint on the sealing layer and then use a non-yellowing urethane paint only during finishing after M, you can create a coating film with good light resistance without being too expensive. You can get a product with At this time, it is desirable to apply the non-yellowing urethane paint used as the final finishing paint so that the film thickness is 10μ or more, especially 20μ or more, and the difference between the non-yellowing urethane paint and the underlying urethane paint is It is best to make them the same color.

〔Effect of the invention〕

As explained above, according to the present invention, a uniform and smooth coating film can be formed on a porous body.

In this case, in the present invention, it is possible to use a relatively small amount of paint for the sealing layer, thereby reducing the amount of volatilization of the highly volatile solvent, thereby reducing the risk of adverse effects on the human body and the risk of fire during work. In addition, by selecting a paint for the surface layer that has appropriate physical properties depending on the purpose, general strength, solvent resistance, chemical resistance, and weather resistance can be reduced. properties, abrasion resistance, airtightness,
A highly functional coating film with excellent watertightness etc. can be obtained.

Therefore, according to the present invention, it is possible to provide an unprecedented practical product as described below. That is, for conventional vehicles,
Cushion materials for chairs, etc. are usually manufactured by separately processing leather, various fibers, etc. into the desired shape to create a skin material, and then covering a foam such as flexible polyurethane foam with this skin material. By using the method of the present invention, there is no need for the complicated process of preparing a separate skin material and attaching it to a foam such as polyurethane foam, as described above, and the surface is uniform, smooth, and high-quality. Functional fashion products can be easily obtained. In addition, the products obtained by the method of the present invention have a wide range of uses, such as fences for baseball fields, furlong fences for stadiums, etc. due to their excellent properties.
It can be used for various purposes such as outdoor play equipment, furniture cushions, medical bedding, children's toys, automobile interior materials, and soundproofing materials.

EXAMPLES The present invention will be specifically explained below with reference to Examples and Comparative Examples; however, the present invention is not limited to the following Examples.

[Example, comparative example]

Using the filler paint 1 surface layer paint and synthetic resin foam shown below, coating films of Examples and Comparative Examples were formed in the following manner.

LLmu 几l and Xingsou (1) Resin (-liquid type) NC○ terminal prepolymer obtained by reaction of pure MDI and polyester polyol (polymer of adipic acid and 1,4 butanediol) and ethylene glycol. NW = 150,000 (2) Diluent cyclohexane 1 part by weight Isopropyl acetate 2 parts by weight (1) : (2) = 1:9 (weight ratio) Viscosity: Approximately 2000 cps Solid content = 10% t *Fm (1) Main agent ■ Polyester polyol (polymerized ten diethylene glycol phthalate MWW18O49 ■ Diluent solvent xylene: toluene: cellosolve acetate = 15:2
5:60 (weight ratio) ■:■==1:1 (weight ratio) Viscosity: Approximately 300 cps (2) Curing agent ■ Non-yellowing polyisocyanate) - (HDI system) MW gradient 750 ■ Diluent solvent xylene: toluene :Cellosolve acetate=15:2
5:60 (weight ratio) ■:■=1:9 (weight ratio) Viscosity: approx. 100 cps (1): (2) =7:1 (weight ratio)
"D11 raw polyurethane foam A: apparent density 0.025 g/cxl, number of cells 50/
Inch polyurethane foam B: Apparent density 0.025 g/a, cell count 35/inch Polyurethane foam C: Apparent density 0.025 g/aJ, cell count 20/inch 111L Paint required for sealing. Spray 35 g/rrr as solid content onto the surface of polyurethane foam A at intervals of 300
an), a sealing layer coating film of about 40 μm was obtained.

Next, a surface layer paint is applied on this sealing layer at a solid content of 60 g/r+? Spray coating was performed to obtain a surface layer coating of approximately 60 μm. The total coating film thickness was about 100μ.

Only the paint required for sealing was sprayed onto the surface of polyurethane foam A at a solid content of 100 g/rd to obtain a coating film with a thickness of about 100 μm.

1 U''1 Spray only the surface layer paint on the surface of polyurethane foam A at a solid content of 100 g/m2 to a thickness of approximately 10 g/m2.
A coating film of 0μ was obtained.

The results of comparing the performance of each of the above coating films are shown in Table 1 below.

Table 1 In Comparative Example 2, the paint penetrated into the foam bubbles and no paint film was formed.

A coating film was obtained in the same manner as in Example 1 except that polyurethane foam B was used.

A coating film was obtained in the same manner as in Example 1 except that Polyurethane Foam C was used.

11 A coating material required for first sealing was spray applied to the surface of polyurethane foam A at a solid content of 15 g/rn' to obtain a coating film of about 15 μm thick for sealing M. Next, a surface layer paint was sprayed on this sealing layer at a solid content of 60g/r and approximately 60g/r.
A surface layer coating film of 0μ was obtained.

*The total film thickness was approximately 75μ.

Made of leather ■The main filler paint is applied to the surface of polyurethane foam A as a solid content of 5 g/rr? Spray coating was performed to obtain a sealing layer coating film with a thickness of approximately 5 μm. Next, a coating material for the surface layer was spray-coated on the sealing layer at a solid content of 60 g/m to obtain a surface JW layer coating film with a thickness of about 60 μm. The total coating thickness is approximately 6
It became 5μ.

The appearance of the coating films of Examples 1 to 4 and Comparative Example 3 was as shown in Table 2 below.

When spraying the paint that requires sealing in Example 1 of Table 2,
A sufficient distance between the foam surface and the spray nozzle was maintained from the start to the end of spraying, so that the solvent was applied to the foam from a distance that could be sufficiently volatilized (the distance between the foam surface and the spray nozzle was 300 mm to 300 mm). 400mm).

When spraying the paint that requires sealing in Example 1,
After starting spraying, spray an amount equivalent to approximately 5 g/rrr as a solid content by keeping the distance between the foam A surface and the spray nozzle close enough that the solvent will hardly evaporate during spraying, and then spray the remaining amount until the solvent evaporates sufficiently. The distance between the foam surface and the spray nozzle was approximately 50 meters at first, and then 300-400 meters.

In Example 1, as a pretreatment for applying the sealing layer, the surface layer paint was sprayed as a solid content at approximately Log/rrr,
The paint for the sealing layer was spray applied before the solvent completely evaporated. As in Example 5, the filler paint was always sprayed from a distance where the solvent could be sufficiently volatilized.

When the adhesion of the coating films of Examples 5 to 7 to the foam was examined, the results were as shown in Table 3 below.

Table 3

Claims (1)

[Claims] 1. A porous body is used as the object to be painted, and a sealing layer paint containing a highly volatile solvent and a film-forming solid content dissolved in the solvent is sprayed onto the object, and a part of the material is sprayed onto the object to be painted. After forming a sealing layer that penetrates into the pores of the object and closes these pores on the surface of the object to be coated at a rate of 10 to 60 g/m^2 so that the pores are not exposed, this sealing layer is applied. A method for forming a coating film on a porous body, comprising applying one or more layers of a surface layer coating material thereon.