JP2021088173A - Rust preventive sheet and rust preventive tray - Google Patents

Abstract

To provide a rust preventive sheet and a rust preventive tray each of which has an excellent rust preventive effect on a rust-prone steel component such as cast iron, adhesion between a rust preventive agent layer and a base material, and good appearance after being heated.SOLUTION: A rust preventive sheet includes a base material, and a rust preventive layer which is provided on at least one surface of the base material and is composed of a coating composition. The coating composition is composed of a thermoplastic resin composed of a polymer using at least one or more monomers having a homopolymer solubility parameter of 9.0-12.0, and a volatile rust preventive agent having a vapor pressure at 20-30°C of 1.0×10-2 Pa or more, and in the coating composition, a ratio of the volatile rust preventive agent to the thermoplastic resin is 1/10 to 10/1 by a mass ratio.SELECTED DRAWING: Figure 1

Description

The present invention relates to a rust preventive sheet and a rust preventive tray.

When storing and transporting metal parts such as automobile parts, especially when transporting them over long distances between various regions of the world, the temperature and humidity are liable to change, and the metal parts are liable to corrode. In such a case, as a method for preventing rust on the metal member, a method such as coating a metal member with rust preventive oil, packing with a vaporizable rust preventive paper or a vaporizable rust preventive film, or the like has been conventionally adopted.

In these methods, the metal member coated with rust preventive oil is packed in a vaporizable rust preventive paper or a vaporizable rust preventive film after installing the metal member in a container such as a tray containing no rust preventive agent. There is.

When applying rust preventive oil to a metal member, a step of applying and removing the rust preventive oil is required, which requires labor and time. Also, when packing with vaporizable rust preventive paper or vaporizable rust preventive film, it is not necessary to apply and remove it like rust preventive oil, but it takes a considerable amount of time and effort to pack a large amount of metal parts. .. Therefore, there is a demand for a method with less work load.

Therefore, by providing the sheet and the tray itself, which is a molded product thereof, with vaporizable rust preventive properties, it is not necessary to apply or remove rust preventive oil before and after storage or transportation of the metal members, and the metal members can be more easily provided. It becomes possible to pack.

As such a technique, Patent Document 1 discloses a multilayer sheet in which a resin film kneaded with a vaporizable rust preventive and a base resin are bonded, and a container for packaging a metal product obtained by secondary molding the sheet. There is.

Japanese Unexamined Patent Publication No. 2007-230568

However, in order to mold a resin film containing a rust preventive, it is necessary to mold at a temperature at which the resin melts. Therefore, if a rust preventive having a high vapor pressure is used, the rust preventive is vaporized and disappears due to the heat during molding. Therefore, it is necessary to use a vaporizable rust preventive that can withstand the heat during molding and suppresses vaporization. Further, since the vaporizable rust inhibitor is kneaded into the resin film, the amount of the vaporizable rust inhibitor that appears on the surface may not be sufficient. Therefore, the rust preventive effect was insufficient to prevent rust on rust-prone metal products such as cast iron. In addition, the adhesion between the rust preventive layer and the base material must be good, and the appearance of the product after heating is also an important factor.

In view of these problems, the present invention provides a rust preventive sheet having an excellent rust preventive effect on rust-prone steel parts such as cast iron, adhesion between the rust preventive layer and the base material, and a good appearance after heating. And to provide a rust preventive tray.

As a result of diligent studies, the present inventors have made the coating composition a predetermined thermoplastic resin and a rust preventive layer composed of a substrate and a coating composition provided on at least one surface of the substrate. By composing with a predetermined vaporizable rust preventive, it is possible to obtain a rust preventive sheet and a rust preventive tray without vaporizing and disappearing the vaporizable rust preventive, which is excellent for rust-prone steel parts such as cast iron. It has been found that it is possible to provide a rust preventive sheet and a rust preventive tray having a rust preventive effect, adhesion between a rust preventive layer and a base material, and a good appearance after heating.

In order to achieve the above object, the present invention is specified as follows.
(1) Base material and
A rust preventive layer composed of a coating composition provided on at least one surface of the base material, and
Including
The coating composition is a thermoplastic resin composed of a polymer using at least one type of monomer having a solubility parameter of a homopolymer of 9.0 to 12.0, and 1.0 × at 20 to 30 ° C. It consists of a vaporizable rust inhibitor with a vapor pressure of ^{10-2 Pa or more.}
A rust preventive sheet, wherein the vaporizable rust preventive agent / the thermoplastic resin has a mass ratio of 1/10 to 10/1 in the coating composition.
(2) The rust preventive sheet according to (1), wherein the base material is composed of a single base material or a laminated laminated base material having a thickness of 12 to 1200 μm.
(3) The rust preventive sheet according to (1) or (2), which is for thermoforming.
(4) The rust preventive sheet according to any one of (1) to (3), wherein the thickness of the rust preventive agent layer is 1.0 to 10.0 μm.
(5) The rust preventive sheet according to any one of (1) to (4), which is used for rust preventive of cast iron.
(6) A rust preventive tray obtained by thermoforming the rust preventive sheet according to any one of (1) to (5).

According to the present invention, a rust preventive sheet and a rust preventive tray having an excellent rust preventive effect on rust-prone steel parts such as cast iron, adhesion between the rust preventive agent layer and the base material, and a good appearance after heating can be provided. Can be provided.

It is sectional drawing of the rust preventive sheet which concerns on embodiment of this invention. It is sectional drawing of the rust preventive tray which concerns on embodiment of this invention.

<Rust prevention sheet>
FIG. 1 shows a schematic cross-sectional view of the rust preventive sheet according to the embodiment of the present invention. The rust preventive sheet according to the embodiment of the present invention includes a base material and a rust preventive agent layer composed of a coating composition provided on at least one surface of the base material. In the embodiment shown in FIG. 1, an undercoat layer is further provided between the base material and the rust preventive agent layer as described later, but the rust preventive sheet according to the embodiment of the present invention is not limited to this. , The undercoat layer does not have to be provided.

(Base material)
The base material of the rust preventive sheet according to the embodiment of the present invention can be formed of, for example, low-density polyethylene, non-crystalline polyethylene terephthalate (A-PET), polystyrene, polypropylene, modified polypropylene, or the like. The base material may be composed of a single base material using these alone, or may be composed of a laminated laminated base material in which a plurality of these are laminated.

The thickness of the base material of the rust preventive sheet according to the embodiment of the present invention is 12 to 1200 μm, more preferably 100 to 900 μm. If it is 12 μm or less, it is difficult to secure the strength after tray molding, and if it is 1200 μm or more, a dedicated facility may be required for coating the base material of the coating composition, which increases the cost.

As the thermoplastic resin used for the base material, it is preferable to use a resin that can be thermoformed at 150 ° C. or lower. If the thermoplastic resin is a resin that can be thermoformed at 150 ° C. or lower, the rust preventive sheet can be easily molded into a rust preventive tray or the like even at a high temperature at which the vaporizable rust preventive is vaporized and disappears. can do.

(Rust inhibitor layer)
The coating composition constituting the rust preventive layer of the rust preventive sheet according to the embodiment of the present invention is a polymer using at least one kind of monomer having a homopolymer solubility parameter of 9.0 to 12.0. It is composed of a thermoplastic resin made of, and a vaporizable rust preventive having a vapor pressure ^{of 1.0 × 10-2 Pa or more at 20 to 30 ° C.} The coating composition constituting the rust preventive layer contains a thermoplastic resin made of a polymer using at least one type of monomer having a solubility parameter of a homopolymer of 9.0 to 12.0. The affinity between the rust preventive agent in the rust preventive agent layer after the composition is applied to the surface of the base material and the thermoplastic resin can be improved, and the strength of the rust preventive agent layer can be increased. The definition of the solubility parameter of the homopolymer in the present invention is as described in Journal of Paint Technology Vol. 42, No. 541, p. 76. The solubility parameter is calculated using the Feedors formula.

Examples of the thermoplastic resin used in the coating composition include acrylic resin, ester resin, vinyl acetate resin, vinyl chloride resin, vinyl chloride-vinyl acetate copolymer, epoxy resin, nitrile resin, butyral resin, and amide resin. Examples thereof include melamine resin, cellulose resin, urethane resin and olefin resin. Moreover, these resins may be used alone or in mixture.

The vaporizable rust inhibitor used in the coating composition has a vapor pressure ^{of 1.0 × 10-2 Pa or more at 20 to 30 ° C.} Examples of the vaporizable rust preventive include cyclohexylamine carbamate, monoethanolamine benzoate, dicyclohexylammonium nitrite, 3-methyl-5-pyrazolone, 3,5-dimethylpyrazole, diisopropylammonium nitrite, 1,2,3-. Examples thereof include benzotriazole and triltriazole. These vaporizable rust preventives may be used alone or in combination.

The thickness of the rust preventive layer is not particularly limited, but is preferably 1.0 to 10.0 μm. When the thickness of the rust preventive layer is 1.0 μm or more, better rust preventive properties can be obtained. If the thickness of the rust preventive layer is up to 10.0 μm, it is highly possible that sufficient rust preventive properties can be obtained. Therefore, the thickness may be 10.0 μm or less in terms of cost. The thickness of the rust preventive layer is more preferably 2.0 to 8.0 μm, and even more preferably 3.0 to 7.0 μm.

In the coating composition, the vaporizable rust preventive / thermoplastic resin has a mass ratio of 1/10 to 10/1. If the amount of the vaporizable rust inhibitor / thermoplastic resin in the coating composition is less than 1/10, the content of the rust inhibitor in the rust inhibitor layer after the coating composition is applied to the base material is small, so that the rust preventive is prevented. The rust effect may decrease. On the other hand, when it exceeds 10/1, the content of the thermoplastic resin in the rust preventive layer after the coating composition is applied to the base material is small, so that the adhesion between the rust preventive layer and the base material is lowered. , The rust preventive layer may fall off from the sheet and tray. In the coating composition, the vaporizable rust preventive / thermoplastic resin is preferably 1/5 to 5/1, more preferably 1/3 to 3/1.

The content of the rust inhibitor in the rust inhibitor layer is preferably ^{0.1 to 20 g / m 2.} If the content of the rust inhibitor in the rust inhibitor layer is ^{less than 0.1 g / m 2} , the amount of the rust inhibitor is small and a sufficient rust preventive effect may not be obtained. If the content of the rust inhibitor in the rust inhibitor layer exceeds 20 g / m ² , the thickness of the rust inhibitor layer may increase and the production cost may increase. The content of the rust inhibitor in the rust inhibitor layer ^{is more preferably 1 to 10 g / m 2} , and even more preferably ² to 8 g / m 2.

The rust preventive layer can be formed by applying a coating composition to the surface of the base material. Alternatively, the rust preventive layer can be formed by providing a base material with an undercoat layer described later and then applying a coating composition to the surface of the undercoat layer. The surface of the base material to which the coating composition is applied may be subjected to surface modification treatment in advance, such as corona treatment, plasma treatment, or ozone treatment, for the purpose of improving adhesion.

Other additives such as a dispersant, a viscosity modifier, a cross-linking agent, an antistatic agent, and a surfactant may be added to the coating composition to be applied to the surface of the base material, if necessary. These can be used alone or in combination of two or more.

An organic solvent can be used as the above-mentioned dispersant. Examples of the organic solvent include methyl isobutyl ketone, butyl acetate, ethylbenzene, xylene, toluene, ethyl acetate, tetrahydrofuran, benzene, methyl ethyl ketone, chloroform, methylene chloride, acetone, cyclohexanone, 1,4-dioxane, butyl cellosolve, isopropyl alcohol and the like. Can be mentioned. These organic solvents may be used alone or in combination. By using the organic solvent as a dispersant, the dispersibility of the rust preventive in the coating composition can be improved and the coating composition can be stabilized.

Further, in order to produce the coating composition, a conventional method can be adopted, and each component can be obtained by dispersing each component with a disperser such as a mixer, a ball mill, a sand mill, or a roll mill. Such a coating composition is applied to a substrate surface or undercoat layer with a coating device such as a wire bar coater, a gravure coater, a roll coater, a reverse coater, a die coater, a spray coater, a comma doctor, a knife coater, a kiss coater, and a dipping coater. A rust preventive layer can be obtained by coating the surface and then drying it.

(Undercoat layer)
In the rust preventive sheet according to the embodiment of the present invention, an undercoat layer may be provided between the base material and the rust preventive agent layer. By providing the undercoat layer, the adhesion of the rust preventive layer to the base material can be enhanced, and the strength of the rust preventive sheet and the rust preventive tray according to the embodiment of the present invention can be enhanced.

As the material used for the undercoat layer, the thermoplastic resin used in the coating composition of the above-mentioned rust preventive layer can be used. Further, since the chemical affinity becomes stronger, the solubility parameter of the thermoplastic resin used for the undercoat layer is preferably close to the solubility parameter of the thermoplastic resin used for the coating composition of the rust preventive layer. , More preferably the same.

When the thickness of the undercoat layer is 0.01 μm or more, the adhesion strength between the rust preventive layer and the base material increases, which is preferable. The thickness of the undercoat layer is preferably 0.01 to 5 μm, more preferably 0.1 to 3 μm.

The rust preventive sheet according to the embodiment of the present invention can suppress rusting of the base material by using it as it is, but it may be thermoformed into a tray or the like as described later. Further, the rust preventive sheet according to the embodiment of the present invention exhibits excellent rust preventive properties when storing and transporting steel members, particularly steel members that are easily rusted such as cast iron.

<Rust prevention tray>
FIG. 2 shows a schematic cross-sectional view of the rust preventive tray according to the embodiment of the present invention. The rust preventive tray according to the embodiment of the present invention is produced by thermoforming the above-mentioned rust preventive sheet. The rust preventive tray is composed of a base material and a rust preventive agent layer, or a base material, an undercoat layer and a rust preventive agent layer, similarly to the rust preventive sheet according to the embodiment of the present invention.

The rust preventive tray can have a tray structure as shown in FIG. 2, for example, by preparing two rust preventive sheets described above and thermoforming each into a predetermined shape. At this time, one rust preventive sheet constitutes a lid portion, and the other rust preventive sheet constitutes a main body portion. The thermoforming of the rust preventive sheet can be carried out at a temperature of 150 ° C. or lower as described above. Further, the rust preventive sheet may be molded by vacuum forming, compressed air molding, vacuum pressure air forming or press molding.

When producing the rust preventive tray according to the embodiment of the present invention, it is particularly preferable to use non-crystalline polyethylene terephthalate (A-PET) as the thermoplastic resin used in the coating composition of the rust preventive sheet. The rust preventive sheet using non-crystalline polyethylene terephthalate (A-PET) in the coating composition has a feature that the molding temperature is low and the vaporizable rust preventive is hard to vaporize and thermally decompose during molding.

The rust preventive tray according to the embodiment of the present invention is not particularly limited and may be used for storing and transporting any member, but when storing and transporting a steel member, particularly a rust-prone steel member such as cast iron. Demonstrates excellent rust prevention.

Hereinafter, examples for better understanding the present invention and its advantages will be provided, but the present invention is not limited to these examples.

(Example 1)
10 parts of VERZONE Crystal # 270 (manufactured by Daiwa Kasei Co., Ltd.), 20 parts of polyester (byron 290, manufactured by Toyobo Co., Ltd.), 30 parts of methyl ethyl ketone, and 40 parts of toluene were dispersed by a ball mill to prepare a coating composition.
This coating composition is applied to an A-PET sheet (KA-20, manufactured by Shinei Kasei Co., Ltd.) having a thickness of 400 μm so as to have a thickness of 7 μm (rust inhibitor amount 4 g / m ² ), and after drying. , Obtained a rust preventive sheet.

(Example 2)
20 parts of VERZONE Crystal # 270 (manufactured by Daiwa Kasei Co., Ltd.), 15 parts of vinyl chloride-vinyl acetate copolymer (solvine A, manufactured by Nissin Chemical Co., Ltd.), 40 parts of isopropyl alcohol, and 25 parts of toluene are dispersed with a sand mill to paint. It was made into a composition.
This coating composition is applied to an A-PET sheet (KA-20, manufactured by Shinei Kasei Co., Ltd.) having a thickness of 400 μm so as to have a thickness of 7 μm (rust inhibitor amount 4 g / m ² ), and after drying. , Obtained a rust preventive sheet.

(Example 3)
20 parts of VERZONE Crystal # 270 (manufactured by Daiwa Kasei Co., Ltd.), 25 parts of butyral resin (manufactured by Eslek BL-5, Sekisui Chemical Co., Ltd.), 30 parts of ethyl acetate, and 25 parts of methyl ethyl ketone are dispersed with a ball mill to form a coating composition. did. This coating composition is applied to an A-PET sheet (KA-20, manufactured by Shinei Kasei Co., Ltd.) having a thickness of 400 μm so as to have a thickness of 6 μm (rust inhibitor amount 3 g / m ² ), and after drying. , Obtained a rust preventive sheet.

(Example 4)
An undercoat solution prepared by diluting chlorinated polyolefin (Supercron 822, manufactured by Nippon Paper Industries Co., Ltd.) with toluene on an A-PET sheet (KA-20, manufactured by Shinei Kasei Co., Ltd.) having a thickness of 400 μm to 10% by mass. Was applied, and an undercoat layer was provided so that the thickness after drying would be 1.0 μm.
Next, VERZONE Crystal # 270 (manufactured by Daiwa Kasei Co., Ltd.) 15 parts, polyester (byron 200, manufactured by Toyobo Co., Ltd.) 7 parts, acrylic resin (Acrydic A-181, manufactured by DIC Corporation) 8 parts, toluene 50 parts. , A coating composition in which 20 parts of methyl ethyl ketone was dispersed by a ball mill was applied onto the undercoat layer so as to have a thickness of 6 μm (the amount of rust preventive agent was 3 g / m ² ), and after drying, a rust preventive sheet was obtained. ..

(Example 5)
An undercoat solution prepared by diluting an amination acrylic polymer (Polyment 350, manufactured by Nippon Shokubai Co., Ltd.) with toluene on an A-PET sheet (KA-20, manufactured by Shinei Kasei Co., Ltd.) having a thickness of 400 μm to 10% by mass. Was applied, and an undercoat layer was provided so that the thickness after drying would be 0.5 μm.
Next, a coating composition obtained by dispersing 20 parts of VERZONE Crystal # 270 (manufactured by Daiwa Kasei Co., Ltd.), 15 parts of urethane-modified polyester resin (Byron UR8200, manufactured by Toyo Boseki Co., Ltd.), 30 parts of methyl ethyl ketone, and 35 parts of toluene with a sand mill. The undercoat layer was coated with a thickness of 8 μm (the amount of rust preventive agent was 4 g / m ² ), and after drying, a rust preventive sheet was obtained.

(Example 6)
A rust preventive sheet was obtained in the same manner as in Example 1 except that VERZONE Crystal # 260 (manufactured by Yamato Kasei Co., Ltd.) was used instead of VERZONE Crystal # 270 (manufactured by Yamato Kasei Co., Ltd.).

(Comparative Example 1)
A rust preventive sheet was obtained in the same manner as in Example 1 except that sodium nitrite was used instead of VERZONE Crystal # 270 (manufactured by Yamato Kasei Co., Ltd.).

(Comparative Example 2)
A rust preventive sheet was obtained in the same manner as in Example 1 except that a polycarbonate (PC) sheet having a thickness of 400 μm was used instead of the A-PET sheet.

(Comparative Example 3)
23 parts of VERZONE Crystal # 270 (manufactured by Daiwa Kasei Co., Ltd.), 2 parts of polyester (byron 290, manufactured by Toyobo Co., Ltd.), 35 parts of methyl ethyl ketone, and 40 parts of toluene were dispersed by a ball mill to prepare a coating composition. This coating composition is applied to an A-PET sheet (KA-20, manufactured by Shinei Kasei Co., Ltd.) having a thickness of 400 μm so as to have a thickness of 5 μm (rust inhibitor amount 4 g / m ² ), and after drying. , Obtained a rust preventive sheet.

(Comparative Example 4)
20 parts of VERZONE Crystal # 270 (manufactured by Daiwa Kasei Co., Ltd.), 15 parts of styrene-butadiene elastomer (JSR TR2000, manufactured by JSR Corporation), and 65 parts of toluene were dispersed with a sand mill to prepare a coating composition. This coating composition is applied to an A-PET sheet (KA-20, manufactured by Shinei Kasei Co., Ltd.) having a thickness of 400 μm so as to have a thickness of 7 μm (rust inhibitor amount 4 g / m ² ), and after drying. , Obtained a rust preventive sheet.

<Evaluation method>
-Rust prevention evaluation A cast iron test piece (50 mm x 30 mm x 0.6 mm) and a rust preventive sheet according to each Example and Comparative Example cut so that ^{the rust preventive layer is length x width = 75 cm 2} It was placed in a 1 L closed container adjusted to 90% RH or more with glycerin water. Next, the case where this was left at 5 ° C. for 4 hours and then left at 50 ° C. for 4 hours was regarded as one cycle, and after performing a test for 3 cycles (8 hours × 3 = 1 day), a cast iron test piece was placed in a closed container. Was taken out and the appearance was observed. At this time, evaluations were made from A to D based on the area where rust was generated on the cast iron test piece. If the evaluation is B or higher, it is considered to have a rust preventive effect that is accepted in the market, and it is passed.
Area of rust:
0% -Evaluation A
1-9% -Evaluation B
10-49% -Evaluation C
50% or more-Evaluation D

-Adhesion evaluation The evaluation was carried out in accordance with JIS Z 0237 "Adhesive Tape / Adhesive Sheet Test Method". If it was 10.0 N / 25 mm or more, the adhesion was evaluated as good (◯), and if it was less than 10.0 N / 25 mm, it was evaluated as poor (×).

-Evaluation of appearance of rust preventive layer after heating When molding the rust preventive sheet according to each example and comparative example on a tray, if the molding temperature is high, the rust preventive is thermally decomposed by heating and colored. Heat suitable for molding the base material of the rust preventive sheet to be used, evaluate the change in the appearance of the rust preventive layer after heating, evaluate uncolored as good (〇), and evaluate as bad (x) with coloring. did.

-Evaluation of rust prevention property after heating Considering the case where the rust prevention sheet according to each Example and Comparative Example is molded into a tray, the rust prevention property was evaluated by the same method as the above rust prevention property evaluation after heating.
The evaluation results are shown in Table 1.

As shown in Table 1, the rust preventive sheets obtained from Examples 1 to 6 had high rust preventive properties.

Comparative Example 1 was inferior in rust prevention property as compared with Examples 1 to 6. This is because by using sodium nitrite having a low vapor pressure, the vaporizing component is less vaporized and the rust prevention property is lowered.

In Comparative Example 2, the rust preventive property and the adhesion between the rust preventive agent layer and the base material were better than those in Examples 1 to 6, but the rust preventive property of the rust preventive sheet after heating was inferior. It became. Since the molding temperature of polycarbonate is relatively high, it is presumed that the vaporizable rust preventive component is vaporized and disappears.

In Comparative Example 3, the adhesion between the rust preventive layer and the base material was inferior to that in Examples 1 to 6. This is because the ratio of the rust preventive to the resin is more than 10/1, so that the content of the thermoplastic resin in the rust preventive layer after the coating composition is applied to the base material is reduced, and the rust preventive is used. It is presumed that the adhesion between the layer and the base material has decreased.

In Comparative Example 4, the adhesion between the rust preventive layer and the base material was inferior to that in Examples 1 to 6. This is because the solubility parameter of the homopolymer is outside the range of 9.0 to 12.0, so that the rust preventive and thermoplastic in the rust preventive layer after the coating composition is applied to the surface of the substrate. The affinity with the resin has deteriorated. Therefore, as the strength of the rust preventive layer decreases, the adhesion between the rust preventive layer and the base material deteriorates.

Claims (6)

With the base material
A rust preventive layer composed of a coating composition provided on at least one surface of the base material, and
Including
The coating composition is a thermoplastic resin composed of a polymer using at least one type of monomer having a solubility parameter of a homopolymer of 9.0 to 12.0, and 1.0 × at 20 to 30 ° C. It consists of a vaporizable rust inhibitor with a vapor pressure of ^{10-2 Pa or more.}
A rust preventive sheet, wherein the vaporizable rust preventive agent / the thermoplastic resin has a mass ratio of 1/10 to 10/1 in the coating composition. The rust preventive sheet according to claim 1, wherein the base material is composed of a single base material or a laminated laminated base material having a thickness of 12 to 1200 μm. The rust preventive sheet according to claim 1 or 2, characterized in that it is for thermoforming. The rust preventive sheet according to any one of claims 1 to 3, wherein the thickness of the rust preventive agent layer is 1.0 to 10.0 μm. The rust preventive sheet according to any one of claims 1 to 4, which is used for rust preventive of cast iron. A rust preventive tray obtained by thermoforming the rust preventive sheet according to any one of claims 1 to 5.

Images