JP2791455B2 - Resin-coated metal plate with excellent punching workability - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin-coated metal sheet excellent in stamping workability, which is suitably used for automobiles, household electric appliances, building materials and the like.

[0002]

2. Description of the Related Art Generally, in the punching of a metal plate, the burrs of the edge of the punched product become larger as the wear of the mold progresses. If the burrs of the edge become too large, the dimensional accuracy at the time of assembling will deteriorate and the product value will decrease. Is performed. However, if the mold replacement or re-polishing is too frequent, the equipment operation rate will decrease and the cost will increase, so the number of sheets that can be punched before the mold replacement or re-polishing becomes necessary Is better as much as possible. That is, in punching a metal plate, the metal plate is required to have excellent punching workability. Therefore, conventionally, in order to give excellent punching workability to a metal plate,
Various surface treatment methods have been proposed.

For example, in the case of an electromagnetic steel sheet, a method of forming an inorganic coating, an organic coating, or a mixed coating thereof is known. As such a method, for example,
Japanese Patent Publication No. 8-12300 proposes a surface treating agent obtained by adding an aluminum salt to magnesium monophosphate and chromic anhydride, and Japanese Patent Publication No. 49-6744 discloses a phosphoric acid type or chromium type. A method has been proposed in which an organic film is formed on the film or a mixed film thereof is formed.

[0004] However, all of the conventionally known methods are premised on the use of a punching oil, and the problem associated with the use of the punching oil, that is, when the punching oil is used for processing a metal plate, the punching oil is used. Problems such as scattering and deteriorating the working environment or causing pollution problems have not been solved.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems in a conventional metal plate used for punching, and has a surface composite resin coating and is free from oil-free oil. An object of the present invention is to provide a resin-coated metal sheet having excellent punching workability.

[0006]

According to the present invention, there is provided a resin-coated metal plate having excellent punching workability, comprising a urethane-based resin having active hydrogen in a molecule and a room-temperature cross-linkable epoxy resin of 1.0.
Mainly of 20 wt% containing a resin obtained by, spherical polyethylene wax particles 0.5 to 20 wt% and the composite resin film is adhered amount 0.2 to 3 g / m of silica particles containing 1 to 30 wt% as SiO ₂ Formed on the surface of the metal plate at ² ,
It is characterized in that the shape of the spherical polyethylene wax is retained in the coating.

In the resin-coated metal sheet according to the present invention, a urethane resin having an active hydrogen, for example, a carboxyl group in a molecule is used as a main resin component for forming a resin film, and the urethane resin is an aqueous dispersion. And aqueous resins such as aqueous solutions. In the present invention,
Although not particularly limited, as the medium, water or water containing a small amount of a water-soluble organic solvent such as alcohol is usually used.

[0008] Such a urethane resin having active hydrogen in the molecule is not particularly limited, but can be obtained, for example, by the following various methods. For example, a urethane prepolymer having a terminal isocyanate group is reacted together with an amino group or a hydroxyl group with a compound having a sulfonic acid group or a carboxyl group, for example, an aqueous solution of an alkali or ammonium salt of diaminocarboxylic acid, and emulsification is performed simultaneously with chain extension. Or a polyhydroxyl compound, a compound having a quaternary ammonium group and a hydroxyl group in the molecule or a compound having an epoxy group and a hydroxyl group in the molecule, etc. are reacted with the polyisocyanate and mixed with water. Methods and the like can be mentioned.

Further, polyhydric alcohols such as polyether, ethylene glycol, propylene glycol, butanediol and hexanediol, which are polymerization products such as tetrahydrofuran, propylene oxide and ethylene oxide, and maleic acid and succinic acid , Adipic acid, a polyester obtained by a dehydration condensation reaction with a polyvalent carboxylic acid such as phthalic acid or a ring-opening polymerization reaction of a cyclic ester, a polyacetal, a polyesteramide, a polyhydroxyl compound represented by a polythioether, and 1 Aromatic polyisocyanate such as 1,5-naphthalenediisocyanate, 4,4-diphenylmethane diisocyanate, phenylene diisocyanate, toluene diisocyanate, or hexamethylene diisocyanate, dicyclohexylmethane diisocyanate , Polyisocyanates represented by aliphatic diisocyanates such as xylylene diisocyanate, and chain extenders represented by the above polyhydric alcohols and low molecular weight diamines such as ethylene diamine, propylene diamine, diethylene triamine, hexamethylene diamine and xylylene diamine. Is reacted in an inert organic solvent such as tetrahydrofuran, acetone, methyl ethyl ketone, ethyl acetate, and toluene to obtain urethane, and after adding water containing an appropriate amount of an emulsifier, distilling off the inert organic solvent. Can be mentioned.

Further, a urethane prepolymer having a terminal isocyanate group is reacted with a polyalkylene polyamine such as diethylene triamine to obtain a polyurethane urea polyamine, to which an aqueous solution of an acid is added, or to the above polyurethane urea polyamine. After adding hydrin, a method of adding an aqueous solution of an acid thereto, or reacting a cyclic dicarboxylic anhydride with the above-mentioned polyurethaneurea polyamine, its alkyl isocyanate adduct or epihalohydrin adduct, and then adding an aqueous solution of a basic substance A method of mixing the above-mentioned polyurethane urea polyamine or its epihalohydrin adduct with sultone acid, lactone acid,
Reacting sodium monohalogenated carboxylate,
Alternatively, a method of reacting (meth) acrylic acid ester, acrylonitrile, or the like, hydrolyzing, and then mixing with water can be used.

In addition to the above, a terminal amino group compound obtained by reacting a diamine with a urethane prepolymer having a terminal hydroxyl group or an isocyanate group obtained from a polyhydroxy compound and a polyisocyanate is emulsified in water using an emulsifier. After that, a method of adding a polyisocyanate to polymerize can be exemplified.

In the present invention, the urethane resin having an active hydrogen in the molecule is preferably JIS K-72.
The Shore hardness of the coating measured according to No. 15 is 30 to 7
Those having a pencil hardness of 0 or more and H or higher are preferably used.

In the production of the resin-coated metal sheet according to the present invention, the coating agent used is, as described above, a resin component for forming a resin film, as described above, together with a urethane-based resin having active hydrogen in the molecule as a crosslinking agent. , A cold-crosslinkable epoxy resin. Thus, as a resin component in a coating agent for forming a resin film, together with a urethane-based resin, by using a cold-crosslinkable epoxy-based resin as a cross-linking agent, the resin wraps around the shear surface in the punching process, and , Has a film strength to withstand extreme pressure between the mold and the metal plate during shearing, and suppresses metal contact between the mold and the metal plate. It can be extended dramatically.

That is, according to the present invention, when the urethane resin has, for example, a carboxyl group as active hydrogen in the molecule, the epoxy group of the epoxy resin reacts with the carboxyl group to form an ester group. Thus, a crosslink is formed, and thus the coating is made dense and tough, and the punching workability is improved.

As a crosslinking agent for a urethane resin having a carboxyl group in a molecule, for example, melamine, isocyanate, aziridine and the like are known in addition to the epoxy resin. Even if used as, in the obtained resin-coated metal plate, the wraparound of the resin film to the shear surface during punching is insufficient,
The effect of suppressing metal contact between the mold and the metal plate is small,
Thus, the punchability is not sufficiently improved.

In the present invention, the cold-crosslinkable epoxy resin has high reactivity with active hydrogen such as carboxyl group, has good compatibility with urethane resin, and softens spherical polyethylene wax particles. A crosslinking reaction occurs at a temperature lower than the temperature, and those having good liquid stability are preferably used. Such epoxy resins include, for example, Denacol EX-313, EX-314, EX-
321, EX-421, EX-512, EX-521,
EX-147, EX-810, EX-614, (
Nagase Kasei Kogyo Co., Ltd.) Ricabond EX-8S, AP
-355B (manufactured by Chuo Rika Kogyo Co., Ltd.) and the like.

Such a cold-crosslinkable epoxy resin is
In the resin coating, the content is preferably in the range of 1.0 to 20% by weight. When the content of the cold-crosslinkable epoxy resin is less than 1.0% by weight in the resin coating, the urethane resin in the resin coating is insufficiently crosslinked, and the resin wraps around the punched fracture surface often. However, the effect of suppressing metal contact with respect to the extreme pressure between the metal mold and the metal plate at the time of punching becomes poor. However, 20% by weight
When the content exceeds 3, the obtained resin film deteriorates in lubricity, and the resin film does not sufficiently reach the shearing surface during the punching process, so that the punching processability is not sufficiently improved. In particular, in the present invention, the cold-crosslinkable epoxy resin is most preferably contained in the resin coating in the range of 1 to 10% by weight.

Further, in the resin-coated metal plate according to the present invention, spherical polyethylene wax particles are contained in the resin coating in an amount of 0.1 mm.
5-20% by weight and chain colloidal silica containing 30 wt% as SiO _2, such a resin film is attached amount
According to the present invention, the spherical polyethylene wax particles are contained in the resin coating while maintaining the spherical shape in the range of 0.2 to 5 g / m ^2. ing.

In the resin-coated metal plate according to the present invention, the content of the spherical polyethylene wax particles in the resin coating is 0.5.
When the amount is less than 10% by weight, the lubricating properties and the punching workability of the obtained resin film are not yet sufficiently improved.
When the amount exceeds 10% by weight, although there is no particular problem in terms of punching workability, the adhesion between the obtained resin coating and the metal plate is poor, and the coating peels off in the punching. In particular, in the present invention, the content of the spherical polyethylene wax particles in the resin coating is preferably in the range of 1 to 10% by weight.

The softening point of the spherical polyethylene wax particles used in the present invention is preferably in the range of 100 to 140 ° C. When the softening point of the spherical polyethylene wax particles is lower than 100 ° C., the polyethylene wax particles are softened and liquefied due to an increase in the mold temperature during the punching process, so that the state of liquid shortage between the metal plate and the mold is caused. And the workability of punching deteriorates. On the other hand, when the softening point of the spherical polyethylene wax particles exceeds 140 ° C., the obtained resin-coated metal plate does not have good punching workability.

According to the present invention, when the required coating agent is applied to the surface of a metal plate and dried, the temperature is lower than the melting point of the spherical polyethylene wax particles, and therefore lower than 100 ° C. And heat-drying, while holding the spherical polyethylene wax particles in the resin coating in a spherical shape, forming a resin coating, thus further enhancing the lubricity of the obtained resin coating and further improving the punching workability of the metal plate. Can be enhanced.

In the present invention, in order to maximize the effect of the spherical polyethylene wax particles, the spherical polyethylene wax particles preferably have a particle diameter in the range of 0.1 to 3 μm. When the particle size exceeds 3 μm, it is difficult to uniformly disperse the particles in the aqueous urethane resin, and as a result, the adhesion of the obtained resin coating to the metal plate is deteriorated. On the other hand, when the particle diameter of the spherical polyethylene wax particles is smaller than 0.1 μm, the effect of improving the punching workability based on the resin film containing the spherical polyethylene wax particles cannot be obtained.

In the present invention, the spherical polyethylene wax includes, for example, Dijet E-17 (manufactured by Kyogo Chemical Co., Ltd.), KUE-1, KUE-5, and KUE-
8 (manufactured by Sanyo Chemical Industries, Ltd.), Chemipearl W-100,
W-200, W-300, W-400, W-500, W
F-640, W-700 (Mitsui Petrochemical Industry Co., Ltd.)
Commercially available products such as Elepon E-20 (manufactured by Nikka Kagaku Co., Ltd.) and the like.

In the present invention, when the content of silica particles in the resin coating is less than 1% by weight, the strength of the obtained coating is not sufficient, and when it exceeds 30% by weight, silica is used as a lubricant. And increases the wear of the mold by increasing the coefficient of friction of the coating and reducing lubricity.

In the present invention, when the amount of the resin film adhered to the metal plate is less than 0.2 g / m ² , the required lubricating effect cannot be obtained in the punching process. However, when the amount of adhesion exceeds 3 g / m ² , the amount of peeling of the composite resin film increases in the punching process, and in the punching process, the release film adheres to a die on a shot product and deteriorates the appearance.

In the resin-coated metal sheet according to the present invention, the metal sheet material to be used is not particularly limited. For example, zinc or a zinc-based alloy-plated steel sheet, and such a steel sheet may be formed by chemical treatment such as chromate treatment or phosphate treatment. A treated product or the like is preferably used.

The resin-coated metal sheet according to the present invention is prepared by dispersing a cold crosslinking epoxy resin together with spherical polyethylene wax particles and silica particles in the above-mentioned aqueous urethane resin to prepare a coating agent. Is applied to a metal plate and dried below the softening point of the spherical polyethylene wax.

[0028]

As described above, according to the present invention, a urethane-based resin containing a cold-crosslinkable epoxy resin is mainly used,
By applying a coating agent containing spherical polyethylene wax and silica particles to a metal plate and drying it below the softening point of the spherical polyethylene wax, it is possible to perform a punching process without applying a punching oil, and furthermore, wear the mold. A resin-coated metal plate having a small amount of resin can be obtained.

[0029]

EXAMPLES The present invention will be described below with reference to examples.
The present invention is not limited by these examples. In the following, the active hydrogen contained in the urethane resin is a carboxyl group.

Example 1 An electrogalvanized steel sheet subjected to chromate treatment (amount of zinc applied: 20 g / m ² , amount of chromium applied: 20 mg / m ² ) was used as a material steel sheet. In the following, the amount of each component is an amount in terms of solid content after forming the resin film. A room-temperature-crosslinkable epoxy resin is blended in a urethane-based resin having a Shore D hardness of 51 (Superflex manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) in an amount of 0.5 to 25% by weight, and spherical polyethylene wax particles (particle diameter 1 to 1) 2 μm, softening point 110
C.) 10% by weight and 10% by weight of silica particles as SiO ₂ were added and dispersed in a resin to prepare a coating agent.

This coating agent is applied to the surface of the above steel sheet by a roll coater so as to have a dry adhesion amount of 1 g / m ^2, and dried at 80 ° C. to form a resin film. I got The thus-obtained resin-coated metal plate was subjected to a sliding test and a punching test to examine a dynamic friction coefficient and punching workability. For comparison, a coating agent was prepared by mixing 5% by weight of a melamine-based, isocyanate-based or aziridine-based crosslinking agent with the same urethane-based resin as described above, and a resin-coated vapor-deposited aluminum-plated steel sheet was obtained in the same manner as above. For each of them, a sliding test and a punching test were performed in the same manner as described above, and a dynamic friction coefficient and punching workability were examined.

The dynamic friction coefficient was determined from the load caused by sliding at a pressing force of 150 kg using a sliding test apparatus. Punching workability was measured using a continuous punching tester, using a die material SKD-11, a die shape of 10 mm square, a clearance of 25%,
A continuous punching test was conducted under the conditions of a punching speed of 80 sheets / min and no use of punching oil, and a burr height of 5
It was evaluated by the number of punches until it reached 0 μm. Table 1 shows the results.

[0033]

[Table 1]

Example 2 In the same manner as in Example 1, 5% by weight of a normal temperature crosslinkable epoxy resin was added to a urethane resin (Shoreflex manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) having a Shore D hardness of 51 of the resin film. 10% by weight of spherical polyethylene wax (softening point 100 ° C.) particles having a particle diameter of 0.1 to 3 μm and silica particles (Si
O ₂ as) 10 wt% were added and dispersed to prepare a coating agent. Also, for comparison, the particle size is 0.
A coating agent was prepared by adding 10% by weight of spherical polyethylene wax particles having a particle size smaller than 1 μm and 4 μm (softening point: 110 ° C.) and dispersing them.

Each coating agent thus prepared was applied on the same steel sheet surface as above at a dry adhesion amount of 1 g / m 2.
^It was applied with a roll coater and dried at 80 ° C. to form a resin film to obtain a resin-coated metal plate to obtain 2,
The performance was evaluated in the same manner as in Example 1. Table 2 shows the results.

[0036]

[Table 2]

Example 3 In the same manner as in Example 1, 5% by weight of a normal-temperature crosslinkable epoxy resin was added to a urethane resin (Shoreflex manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) having a Shore D hardness of 51 of the resin film. , Spherical polyethylene wax particles (particle size 1-2μ)
m, softening point 100 ° C.) 0 to 25% by weight and silica particles as S
iO ₂ 0 to 35 by weight percent dispersed as to prepare a coating agent.

Each coating agent thus prepared was applied to the same steel sheet surface as above at a dry adhesion amount of 1 g / m 2.
^It was applied with a roll coater and dried at 80 ° C. to form a resin film to obtain a resin-coated metal plate to obtain 2,
The performance was evaluated in the same manner as in Example 1. Table 3 shows the results.

[0039]

[Table 3]

Example 4 In the same manner as in Example 1, 5% by weight of a room temperature crosslinkable epoxy resin was added to a urethane resin (Shoreflex manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) having a Shore D hardness of 51 of the resin film. A coating agent was prepared by dispersing 10% by weight of spherical polyethylene wax (particle diameter 1-2 μm, softening point 100 ° C.) particles and 10% by weight of colloidal silica particles as SiO ₂ .

Each of the coating agents thus prepared was applied on the same steel plate surface as above in a dry adhesion amount of 0.2 to 3 g.
/ M ² , applied with a squeezing roll, dried at 80 ° C. to form a resin film, and a resin-coated metal plate was obtained.
The performance was evaluated in the same manner as in Example 1. Table 4 shows the results.

[0042]

[Table 4]

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI C09D 175/04 C09D 175/04

Claims (3)

(57) [Claims] 1. Spherical polyethylene wax particles comprising a urethane-based resin having active hydrogen in the molecule containing 1.0 to 20% by weight of a cold-crosslinkable epoxy resin as a main component.
5 to 20% by weight and 1 to 3 of silica particles as SiO ₂
A composite resin film containing 0% by weight has an adhesion amount of 0.2 to 3 g / m.
^{2. A} resin-coated metal plate having excellent punching workability, wherein the metal film is formed on the surface of the metal plate and the shape of the spherical polyethylene wax is retained in the coating. 2. The spherical polyethylene wax particles having a particle diameter of
The resin-coated metal plate according to claim 1, wherein the thickness is in a range of 0.1 to 3 µm. 3. The spherical polyethylene wax particles having a melting point of 1
The temperature is in the range of 00 to 140 ° C.
The resin-coated metal plate as described.