JP4980269B2 - Resin coated metal plate - Google Patents

Description

  The present invention relates to a resin-coated metal plate used for home appliances, containers, partitions, desks and other furniture, and more particularly to a resin-coated metal plate having a warm touch.

  Conventionally, a method of forming a resin film on the surface of a metal plate in order to improve designability and corrosion resistance is known. The resin film is required to have good workability, corrosion resistance, scratch resistance, and the like, and it is a conventional problem to improve these characteristics.

  By the way, metal is a material with high thermal conductivity, but the problem is that it can not be held by hand when the contents are hot due to the large thermal conductivity (for example, canned drinks, electronic equipment housings, etc.) On the other hand, there is a problem that the cold tactile sensation when touched with a hand gives discomfort. In particular, when a resin-coated metal plate is used for applications such as desk furniture and partitions that are frequently touched by humans, it is required to improve warm feeling (warm feeling).

  For this reason, examination which gives heat insulation to a resin coating metal plate is performed. For example, Patent Document 1 discloses a technique for forming a coating film from a coating composition to which a foaming agent is added and imparting heat insulation properties to the coating film in addition to vibration damping properties and soundproofing properties. However, since the strength of the coating film after foaming is lowered, bending workability and wrinkle resistance are lowered.

  On the other hand, Patent Document 2 discloses a metal can having a heat insulating effect by containing hollow fine particles and / or thermally expandable fine particles in the lower layer of the upper and lower two-layer coating films. However, since the technology described in Patent Document 2 is a technology for beverage cans, it has been evaluated for its ability to produce cans. Not.

Patent Document 3 discloses a coating film structure for an electronic device casing in which nonporous hollow beads are dispersed in a coating film. However, since the amount of hollow beads is 20% by mass or less and is small, it is insufficient in terms of ensuring warmth.
Japanese Patent Laid-Open No. 2005-206736 JP 2005-193533 A Japanese Unexamined Patent Publication No. 2000-239577

  In view of the above-described circumstances, the present invention provides a resin-coated metal plate that is excellent not only in warmth, but also in all of the characteristics of scratch resistance, 0T bending workability, and contamination resistance. It was raised as an issue.

  The present invention is a resin-coated metal plate in which at least two resin films are formed on the surface of the metal plate, and the lower layer other than the outermost layer contains inorganic hollow particles of more than 20% by mass to 70% by mass or less. A particle-containing layer is present, the particle-containing layer has a thickness of 15 μm or more and 50 μm or less, and the average particle diameter of the hollow particles is 25 μm or less and has a gist where it is smaller than the thickness of the particle-containing layer. The resin-coated metal plate preferably has a pencil hardness of H or higher.

  According to the present invention, it is possible to provide a resin-coated metal plate which is excellent not only in warm feeling but also in all of the properties of scratch resistance, 0T bending workability, and contamination resistance. This resin-coated metal plate is excellent in scratch resistance, 0T bending workability, etc., so there are no inconveniences such as scratches or film peeling in the manufacturing process or product transfer process, so yield loss can be reduced. It has also become possible to suppress quality degradation during use. Therefore, it is suitable for application where there are many opportunities to be touched by human hands such as home appliances, containers, partitions, desks and the like.

  In the resin-coated metal plate of the present invention, an aluminum plate, a copper plate, a cold-rolled steel plate, a hot-dip galvanized steel plate, an electrogalvanized steel plate, an alloyed hot-dip galvanized steel plate, or the like can be used as the original plate.

  The resin-coated metal plate of the present invention has at least two or more resin films, and a lower layer other than the outermost layer has a particle-containing layer in which inorganic hollow particles are contained in an amount of more than 20% by mass to 70% by mass or less. It exists.

  The resin-coated metal plate of the present invention has the simplest structure with a two-layer structure consisting of only the outermost layer and the particle-containing layer. Of course, a resin film having a structure of three or more layers may be used. For example, a structure in which a particle-free layer having a resin composition different from the outermost layer exists between the outermost layer and the particle-containing layer, and between the particle-containing layer and the metal plate. The structure in which the particle-free layer is present can be appropriately selected. In addition, the particle-containing layer may be divided into a plurality of layers, and in this case, the type and content of the particles may be the same or different. Below, although the case of the upper and lower two layer structure of an outermost layer and a particle-containing layer is demonstrated, as above-mentioned, in this invention, it is not limited to this structure.

  The outermost layer is a layer having no hollow particles. This is to prevent the formation of irregularities on the surface of the coating film due to the presence of the particle-containing layer and the falling of the hollow particles during processing by providing an outermost layer that does not contain particles. When the thickness of the outermost layer or other layers intervene, the thickness from the particle-containing layer closest to the outermost layer to the surface of the resin-coated metal plate (surface opposite to the metal plate) is preferably 10 to 50 μm. In addition, the thickness of a layer can be measured by the method of converting into specific gravity from film | membrane mass, and can be calculated | required also by the method of carrying out the microscope observation (SEM photograph observation) of the cross section of a resin film.

  The thickness of the inorganic hollow particle-containing layer (lower layer) is 15 to 50 μm. When the particle-containing layer is composed of multiple layers, the total thickness is within the above range. To obtain a warming effect, the thickness of the particle-containing layer is required to be 15 μm or more, but if it exceeds 50 μm, cracks may occur in the resin film or the hollow particles may fall off during processing. Considering the balance between the warming effect and processability, the thickness of the particle-containing layer is more preferably 25 to 45 μm, and further preferably 30 to 40 μm.

The inorganic hollow particles used in the present invention are particles having an outer shell made of an inorganic material and a hollow inside. Since this cavity imparts a heat insulating effect to the resin film, a warm feeling effect is exhibited. Examples of the inorganic material include glass, silica, shirasu, alumina, zirconia, and the like.
When the required amount of the present invention is added to the hollow particles of the organic material, the scratch resistance is lowered and the resin film strength is also deteriorated. Therefore, the organic hollow particles are not used in the present invention.

  As the inorganic hollow particles, those having an average particle size of 25 μm or less are used. If it exceeds 25 μm, particles may fall off during bending. Further, it is not preferable because the stain resistance (characteristic that dirt hardly remains on the surface of the resin film) is lowered. A more preferable average particle diameter is 20 μm or less, and more preferably 15 μm or less. However, if the particle size is too small, it is not preferable because the handleability is inferior or the hollow particles are aggregated at the time of preparing the coating material, resulting in performance deterioration and poor coating appearance. Therefore, the average particle diameter is preferably 1 μm or more, more preferably 3 μm or more, and further preferably 5 μm or more.

  Examples of the inorganic hollow particles satisfying the above particle size range include “Sphericel (registered trademark)” series of glass hollow particles of Potters Ballotini. This “Sphericel (registered trademark)” series glass balloon is suitable because it has a high pressure resistance (69 MPa), and has improved scratch resistance and resin film strength. In addition, a catalog value can be employ | adopted for the said average particle diameter, or the 50% volume average particle diameter by a laser diffraction method (scattering type) is employable.

  Even if the inorganic hollow particles have an average particle diameter in the above range, when hollow particles having an average particle diameter exceeding the thickness of the particle-containing layer are used, a part of the hollow particles protrudes from the particle-containing layer. End up. When the hollow particles protrude, irregularities on the surface of the outermost layer may be increased, resulting in a decrease in contamination resistance. Moreover, it is not preferable because dropout during bending is likely to occur. Therefore, the average particle size of the hollow particles needs to be smaller than the thickness of the particle-containing layer. When a plurality of particle-containing layers are provided, hollow particles having an average particle size smaller than the thickness of each particle-containing layer are used.

  The said inorganic type hollow particle shall be more than 20 mass% and 70 mass% or less as the quantity in a particle | grain content layer (in the case of multiple layers, total quantity). If the amount is 20% by mass or less, sufficient warming effect cannot be obtained. However, if hollow particles are added in excess of 70% by mass, the unevenness of the resin film becomes large even if a particle-free outermost layer is provided. Contamination will decrease. In addition, the resin film may peel off or the hollow particles may fall off during bending, which is not preferable. From the viewpoint of the balance between the warm feeling effect, stain resistance and processability, the more preferable lower limit of the amount of hollow particles is 30% by mass, and the more preferable lower limit is 40% by mass. Moreover, the upper limit of the more preferable amount of hollow particles is 60% by mass, and the more preferable upper limit is 55% by mass.

  In the present invention, both the outermost layer and the particle-containing layer are resin films, and examples of the resin constituting the resin film include polyester resins, acrylic resins, urethane resins, polyolefin resins, fluorine resins, and silicones. And a mixture of these resins or a modified resin. Considering characteristics such as bending workability, film adhesion, and corrosion resistance, an organic solvent-soluble (amorphous) polyester resin is preferable. As the organic solvent-soluble polyester resin, “Byron (registered trademark)” series manufactured by Toyobo Co., Ltd. is preferable in that a wide variety of types can be obtained. In consideration of interlayer adhesion between the outermost layer and the particle-containing layer, both layers are preferably made of the above polyester resin.

  The polyester resin may be crosslinked with a melamine resin or the like. As the melamine resin, there are “Sumimar (registered trademark)” series manufactured by Sumitomo Chemical Co., Ltd. and “Cymel (registered trademark)” series manufactured by Mitsui Cytec. The ratio of the resin and the cross-linking agent may be blended so that the cross-linking agent (after reaction) is 5 to 30% by mass in the resin film after drying from the viewpoint of the balance between processability and durability. preferable.

  In order to produce the resin-coated metal sheet of the present invention, it is preferable to employ a method in which a raw material composition for a resin film is prepared and applied to the original sheet and dried. As the raw material composition, a resin, a crosslinking agent added if necessary, etc., diluted with an organic solvent or the like to have a viscosity suitable for coating is used. The organic solvent is not particularly limited, but aromatic hydrocarbons such as toluene and xylene; aliphatic esters such as ethyl acetate and butyl acetate; alicyclic hydrocarbons such as cyclohexane; aliphatic carbonization such as hexane and pentane. Hydrogen etc .; Ketones such as methyl ethyl ketone and cyclohexanone are listed. The solid content concentration of the raw material composition is preferably about 5 to 60% by mass.

  Various known additives used in the field of resin-coated metal sheets, such as pigments such as titanium oxide, matting agents, rust preventives, anti-settling agents, waxes, etc., to the raw material composition as long as the object of the present invention is not impaired. An agent may be added. In addition, conductive fine particles such as nickel powder and permalloy, and additives for imparting heat dissipation such as carbon black may be added.

  The method for applying the raw material composition to the original plate is not particularly limited, and a bar coater method, a roll coater method, a spray method, a curtain flow coater method, or the like can be employed. Although drying is performed after coating, in a crosslinking agent addition system, it is preferable to perform drying by heating at a temperature at which the crosslinking agent can react. Specifically, heat drying is preferably performed at 100 to 250 ° C. for about 1 to 5 minutes. The original plate may be subjected to a known surface treatment (primary treatment) such as chromate treatment, non-chromate treatment, and phosphate treatment in advance for the purpose of improving corrosion resistance and improving adhesion to the resin film. Good.

  The present invention will be described in more detail with reference to the following examples. However, the following examples are not intended to limit the present invention, and modifications within the scope of the present invention are included in the present invention. In the following, “%” represents “mass%”.

Experimental Example An electrogalvanized steel sheet having a plate thickness of 0.8 mm (plating adhesion amount: 20 g / m ^{2 on} each side) was used as the original sheet. The original plate was pretreated with “CTE-213” manufactured by Nippon Parkerizing Co., Ltd. in advance. The drying temperature was 100 ° C. at the ultimate plate temperature, and drying was performed for 1 minute. The amount of adhesion was 100 mg / m ² .

  The raw material composition for the outermost layer includes Toyobo's organic solvent-soluble polyester resin “Byron (registered trademark) 290”, melamine resin (“Sumimar (registered trademark) M-40ST”: manufactured by Sumitomo Chemical Co., Ltd .: 80% of solid content) and titanium oxide (“Taipeku CR-50” manufactured by Ishihara Sangyo Co., Ltd .: average particle size of 0.25 μm), which is a white pigment for imparting design properties, is 40% polyester resin Melamine resin is 10% and titanium oxide is 50%. Further, a xylene / cyclohexanone mixed solvent (xylene: cyclohexanone = 1: 1) is added so that the solid content concentration of the raw material composition is 50 to 60%, and the mixture is stirred with a hand homogenizer at 10,000 rpm for 10 minutes, and the viscosity is appropriately adjusted. It was adjusted.

In addition, as the raw material composition for the hollow particle-containing layer, a material containing any one of the following hollow particles as shown in Table 1 was used instead of the titanium oxide for the outermost layer.
Hollow particles A: Glass hollow particles “Sphericel (registered trademark) HSC-110” manufactured by Potters Barotini Co., Ltd. Average particle size: 13 μm
Hollow particles B: Glass hollow particles “Glass Bubbles S60HS” manufactured by Sumitomo 3M Limited, average particle size 27 μm (for comparison)
Hollow particle C: Crosslinked styrene-acrylic resin hollow particle “SX866 (A) primary particle size 0.3 μm (comparative) manufactured by JSR Corporation

  The raw material composition for the hollow particle-containing layer prepared as described above was applied to the original plate with a bar coater so as to have the film thickness shown in Table 1, and the final plate temperature was 230 ° C. for 2 minutes in a hot air drying furnace. Baking was performed to form a hollow particle-containing layer. The amount of adhesion was adjusted by changing the count of the bar coater. The film thickness in the table was obtained by observing the cross section of the resin film with a microscope (SEM photograph observation) and determining the thickness of the portion where no hollow particles were present.

  Moreover, on the hollow particle-containing layer, the raw material composition for the outermost layer was coated and baked in the same manner as described above to produce a resin-coated metal plate. Experiment No. 20 is a comparative example in which the outermost layer was not coated. The characteristics were evaluated by the following evaluation methods and are shown in Table 1.

[Warming temperature difference]
The resin-coated metal plate was punched into a φ50 mm disk from the metal plate side so that the burrs were upward when viewed from the painted surface. The sample was placed on a hot plate maintained at 65 ° C. with the resin film facing upward, and the resin film surface temperature after 5 seconds was measured. In the temperature measurement, a contact thermometer (a digital thermometer “CT-700S” manufactured by CUSTOM and a thermocouple “LK250” manufactured by CUSTOM) was used. The lower the measured temperature, the more difficult the resin film conducts heat, and there is a warming effect. It was 58 degreeC when measured with the unpainted sample with a metal plate. The warming temperature difference in Table 1 indicates the temperature obtained by subtracting this 58 ° C. from the temperature measured for the sample. In addition, the determination was -5 ° C. or lower for ◎, −4 to −2 ° C. for ◯, and −1 ° C. or higher for X.

[Scratch resistance (pencil hardness)]
A pencil hardness test according to JIS K5600-5-4 was performed. The judgment criteria were as follows. H or higher was marked with ◯, and HB or lower with x.

[Contamination resistance]
In the pencil hardness test, the pencil core is sharpened by sliding between the resin film and the pencil. The residue of the pencil core adhering to the unevenness of the resin film was regarded as a stain, and it was determined whether this stain was easy to wipe off. Specifically, after performing a pencil hardness test using an H pencil, gauze (manufactured by Kawamoto Sangyo Co., Ltd .; sterilization dekuze (registered trademark)), 30 cm × 30 cm gauze is folded into 1/16 size, and about 8 cm square 10 times, and gently wiped by hand. By changing the wiping position of the gauze every reciprocation, the pencil core adhered to the gauze was prevented from re-adhering to the resin film. The case where almost no trace of the pencil remained on the surface of the resin film was rated as ◯, and the case where the trace remained was marked as x.

[Bending workability]
Using the type 2 test apparatus described in JIS K5600-5-1, the test piece was bent by 180 ° and then pressed by a hydraulic press machine to perform 0T bending. Cellophane tape (manufactured by Nichiban Co., Ltd .; “Cellotape (registered trademark) CT405AP-24”) is applied to the resin film of the bent part (the resin film is outside the bent part after bending), and then peeled off by hand, and the film is peeled off. The state was visually observed. If there was peeling, it was rated as x.

  Since the resin-coated metal plate of the present invention is excellent in warm feeling, scratch resistance, stain resistance, and bending workability, it is an opportunity for humans to touch it by hand, such as home appliances, containers, partitions, desks, and other furniture. It is suitable for many applications.

Claims (2)

  A resin-coated metal plate having at least two resin films formed on the surface of the metal plate, wherein a particle-containing layer in which inorganic hollow particles are contained in an amount lower than 20% by mass to 70% by mass in a lower layer other than the outermost layer. The resin-coated metal sheet is present, wherein the particle-containing layer has a thickness of 15 μm or more and 50 μm or less, and the average particle diameter of the hollow particles is 25 μm or less and smaller than the thickness of the particle-containing layer. The resin-coated metal plate according to claim 1, wherein the pencil hardness is H or higher.