JPH01122432A - Highly-slidable precoated metal sheet - Google Patents

Abstract

PURPOSE:To improve sliding property, mar resistance, and mold release property while keeping processability, by a method wherein a kind or more of polyolefin wax or perfluorocarbon resin wax as a sliding agent and silicon resin as a surface lubricant at need are added to a resin coating. CONSTITUTION:1.0-10.0wt.% of a kind or more of either polyolefin wax or perfluorocarbon resin wax whose mean particle diameter is 7-40mum is contained in a sliding agent based on a weight of a coating composition. 0.01-0.1wt.% silicon resin is contained in the sliding agent based on the weight of the coating composition to improve surface lubricating property of a coating at need. A matter whose molecular weight Mn of 8000 or less is preferable for the silicon resin as the lubricating agent. Coating which is common use for precoating of a metallic plate is good for a base agent of the coating composition for precoating. Ground treatment of phosphoric acid or chromate is performed to a washed metallic coil or sheet, a primer is applied to the same and the above-mentioned coating composition is applied to the same as a finish coating.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a highly slidable precoated metal plate that is excellent in scratch resistance, slip resistance, mold releasability, and scratch resistance.

[Conventional technology]

As is well known, pre-coated metal plates are used for a wide variety of purposes due to their performance such as workability, weather resistance, corrosion resistance, and chemical resistance, as well as their design and smooth appearance. In order to improve adhesion with the undercoat and corrosion resistance, phosphoric acid and chromate-based (reactive type, coating type) base treatment is applied, and the top coat is made of well-known vinylidene fluoride, silicone polyester, high We use resin paints such as molecular polyester, oil-free polyester, and acrylic.

Pre-coated metal plates are used for roofs, wall materials, siding,
It is widely used in building materials such as bandrels and shutters, and electrical products such as refrigeration showcases and video chassis 1 casings, but most of them involve processing such as roll forming, bending, and pressing. When processing such as roll forming, bending, and pressing is involved, the type of paint is selected to withstand each type of forming. As for the type of resin that makes up the paint, soft resins have to be selected in order to improve the spreadability of the paint film, and as a result, the paint film is susceptible to scratches and friction during molding, contact during handling, and impacts. There are problems of quality deterioration and yield reduction due to occurrence of scratches, and unavoidable deterioration of design and functionality due to friction after production. On the other hand, if a hard resin is selected in order to increase the hardness of the coating film and make it difficult to scratch, the coating film will have poor elongation and cracks will occur in the processed area. Because they have the contradictory properties of processability and coating hardness, it is extremely difficult to satisfy both properties, and the reality is that paints are designed at the expense of one property or the other. be.

[Problem that the invention seeks to solve]

This invention was made in view of the above-mentioned current situation, and in order to balance the workability that is difficult to achieve without impairing the original performance of paints in the conventional technology, it aims to improve the workability that is the lifeblood of pre-coated metal plates. The objective is to develop a pre-coated metal plate that has significantly improved sliding properties, scratch resistance, slip properties, and mold release properties while maintaining the following properties.

[Means for Solving the Problems] As a result of various studies, the present invention incorporates a sliding agent ( Particle size 7 to 40 μ- as a sliding property improver)
1.0 to 10.0% by weight of at least one type of polyolefin wax or perfluorocarbon resin wax, and 0.0% by weight of a silicone resin as a surface leveling agent if necessary. O1~0
．． By adding 1% by weight, we have developed a highly sliding pre-coated metal plate that has excellent scratch resistance, mold releasability, slipperiness, and scratch resistance without impairing the processing performance of the coating film. .

In general, as the sliding property improver, wax such as powder or paste dispersed in a solvent such as tetrafluoroethylene, polyethylene, or polypropylene, alumina, silicon carbide, and ceramics thereof can be considered.

However, although ceramics such as alumina and silicon carbide increase the hardness of the coating film, they reduce workability and are not effective in terms of sliding properties (slip properties and mold release properties). Also alumina,
Silicon carbide and other materials are very hard, so there is a problem that each sliding property improving agent protruding outside the coating film can damage machinery such as roll forming in a short period of time, shortening its life. Since it has a relatively large specific gravity, it tends to settle and requires sufficient stirring of the paint during painting, and it also tends to aggregate in the paint, causing coating defects such as color unevenness and coating unevenness.

On the other hand, sliding agents made of waxes such as tetrafluoroethylene, polyethylene, and polypropylene are added to paints in the form of a powder or a paste dispersed in a solvent. It exists dispersed in a floating state and improves the scratch resistance, mold release, slip properties, and scratch/scratching properties of the coating surface. Such a sliding agent is effective even when it is not completely melted during baking and remains in a dispersed state. There are no problems such as damage to machinery such as roll forming, sedimentation of sliding agent, and coating defects as mentioned above.

Thus, according to the invention, the sliding agent has an average particle size of 7 to 40
A coating composition (more precisely, dried Post-coating film) Contains 1.0 to 1000% by weight based on the weight. If the average particle diameter of the sliding agent is less than 7 μm, sufficient sliding resistance cannot be obtained, whereas if it exceeds 40 μm, the smoothness of the coated film surface will decrease.

If this amount is less than 1.0% by weight, the sliding resistance will not be sufficient, and if it exceeds 10.0% by weight, the gloss will decrease.

Note that this sliding agent may be colored.

Further, according to the present invention, in order to improve the surface smoothness of the coating film, silicone such as polyalkylsiloxane such as polyether-modified dimethylsiloxane, polyether-modified methylpentylsiloxane, polyester-modified dimethylsiloxane, etc. The resin is contained in an amount of 0.01 to 0.1% by weight based on the weight of the coating composition (coating film after drying). The silicone resin that functions as a surface smoothing agent here is
Preferably, the molecular weight Mn is 8000 or less. molecular weight is 8
If it is higher than 000, craters will occur on the coating surface. In addition, the amount of silicone resin blended is less than 0.01% by weight and 0.01% by weight.
If it exceeds 1% by weight, craters will occur on the coating surface.

The base of the coating composition for precoating to which polyolefin wax or polyfluorocarbon wax is added as a sliding agent and silicone resin as a surface smoothing agent according to the present invention may be any coating commonly used for precoating metal plates. For example, vinylidene fluoride resin paint, silicone polyester resin paint, silicone acrylic resin paint,
Polyester resin paint (including alkyd resin paint),
Examples include acrylic resin (including self-crosslinking type) paints and melamine resin paints.

The coating composition may contain coloring pigments such as titanium dioxide, carbon black, iron oxide, phthalocyanine blue, and quinacridone red; calcium carbonate, kaolin,
Extender pigments such as barium sulfate; Kisi μ・n, Tsurpets 1
Solvents such as 00, Tsurpez 150, cyclohexanone, isophorone, cellosolve acetate, and butyl cellosolve; other additives such as surfactants, suspending agents, and antifoaming agents may be used.

Coating of such a coating composition onto a metal base plate is usually carried out as follows. In order to improve the adhesion and corrosion resistance of pre-greased and cleaned metal coils or sheets with the undercoat,
A phosphoric acid or chromate base treatment (reactive type, coating type) is performed, a well-known polyester, epoxy, or vinyl chloride base coat is applied as an undercoat, and then the coating composition of the present invention is applied as a topcoat. Coating can be carried out using a roll coater, curtain coater, or the like.

〔Example〕

In the following Examples and Comparative Examples, performance tests of coating films were conducted as follows.

(1) Appearance Judgment was made visually.

(2) Workability (bending property) The test method was based on JIS H4001 (6, 4).
Judgment was made based on cracks in the coating film.

(3) Sliding property a) Scratching property (al Erichsen hardness tester 5k load labyrinth property test method is type 318 Erichsen hardness needle (ball diameter = 0.
75mm diameter, Mizoa metal constitution! I) 5k on the coating surface
The test was performed by applying a load of g and reciprocating motion, and the evaluation was based on the number of times until the coating film broke.

(b) Scratchability A 10 yen coin (no buzzer) was held at an angle of 45° to the painted surface and scratched with a load of 11 qr to determine the extent to which the paint film was torn.

(a) Slip resistance (a) Slip load test method: Measured using a Heidon 14 type surface property measuring machine. The conditions were to use a stainless steel ball with a ball diameter of 10, and a vertical load of 2.
Evaluation was made using the frictional resistance value at a speed of 00 g and a speed of 50 cranes/min.

伽) Coefficient of dynamic friction It was determined by tensile load (slipping load) ÷ vertical load = coefficient of dynamic friction.

We conducted a test in which vinylidene fluoride resin paint was applied to the surface. After surface treatment of the above aluminum plate, the following epoxy resin paint was applied using a bar coater and baked and dried at a plate temperature of 200° C. for 50 seconds to form an undercoat layer with a thickness of 5 μm.

Melamine resin 10.8 Titanium dioxide 15.0 Cellosolve acetate 13.4 total
100.0 Next, a series of vinylidene fluoride resin paints were applied using another bar coater, and baked and dried at a plate temperature of 240°C for 75 seconds to obtain a top coat layer with a thickness of 20 μm.

A paint having the following composition was used as the base for a series of vinylidene fluoride resin paints.

Acrylic resin 27.6 Titanium dioxide 20.6 Isophorone
27.7 total
100.0 This vinylidene fluoride resin paint (disversion type) was mixed with tetrafluoroethylene wax (average particle size 9 μm), polyethylene wax (average particle size 25 μm), and polypropylene wax (average particle size 10 μm) as a sliding agent.
A top coating composition of Example 1 was prepared by adding silicone resin (polyether-modified dimethylsiloxane) as a surface smoothing agent in the amounts shown in Table 1. The paint of Comparative Example 1 contained neither a sliding agent nor a surface smoothing agent.

The results of investigating the performance of the obtained pre-coated metal plate were
Shown in the table.

Referring to Table 1, all sliding agents are found to have the effect of improving sliding properties, but among them, products containing 5% and 10.0% by weight of tetrafluoroethylene are particularly effective. The bendability was the same as that of the comparative example in which no sliding agent was added, and the sliding performance was significantly improved in each sliding performance (Erichsen hardness meter 5 kg load rolling stock test, scratch resistance). The improvement effect was confirmed. In the case of either sliding agent, the effect of improving sliding properties is seen as the amount added increases.

In this example, a high molecular weight polyester resin paint having the following composition was used as the base paint.

Melamine resin 7.0 Titanium dioxide 22.2 Tsurupetsu 150 15.0 Cellosolve acetate 8.6 total
100.0 To this base paint, as in Example 1, tetrafluoroethylene wax, polyethylene wax, and polypropylene wax were added as sliding agents, and silicone resin was added as a surface smoothing agent. In addition, a paint was created in which only polyethylene wax was added without adding silicone resin. Moreover, as a comparative example, one in which no sliding agent and surface smoothing agent were added was used.

The painting was carried out in the same manner as in Example 1, except that the following high-molecular polyester resin paint was used as the undercoat and the coating was applied at 180°C, 80°C.
Bake dry for 0 seconds, and top coat at 230℃, 6
A coating film with a thickness of 15 μm was obtained by baking and drying for 0 seconds.

Melamine resin 4.8 Titanium dioxide 12.1 Xylene 8.6 Cellosolve acetate 1O10 total
100.0 The performance test results of the obtained precoated metal plate are shown in Table 2.

Referring to Table 2, all sliding agents are found to have the effect of improving sliding properties, but among them, polyethylene (2.5% by weight) is particularly effective, and the bendability of OT and sliding agents is found to be particularly effective. It showed the same performance as the comparative example without additives, and the effect of the sliding agent was seen in the coating film hardness and each sliding performance (Erichsen hardness meter 5 kg load billing test, dynamic friction coefficient measurement, sliding load measurement) . Of each sliding performance, Erichsen hardness tester 5kg
More than 20 times better in terms of load floating property, 0 in dynamic friction coefficient measurement
．． 02 to 0.08 was also smaller, and the sliding load was 16 g less, confirming a significant sliding property improvement effect. Tetrafluoroethylene wax and polypropylene wax are effective in improving sliding properties in dynamic friction coefficient and sliding load measurements. In the case of either sliding agent, the effect of improving sliding properties is seen as the amount added increases.

3 and 3 In the same manner as in Example 2, an aluminum plate was subjected to surface treatment and then undercoated and top coated. An oil-free polyester resin paint having the following composition was used as the base for the top coat.

Melamine resin 10.0 Titanium dioxide 30.0 Butanol 3.5 Tsurupetsu 150 10.0 The performance of the obtained precoated metal plate was as shown in Table 3.

Referring to Table 3 in the margin below, in the case of oil-free polyester, all sliding agents had similar effects on improving sliding properties.

The bendability showed the same performance as 2T and a comparative example in which no sliding agent was added, and the coating film hardness and each sliding performance (Erichsen hardness tester 5kgriJ heavy billing/PL test, dynamic friction coefficient measurement, sliding load measurement) , scratch resistance), the influence of the sliding agent can be seen. Of each sliding performance, Erichsen hardness tester 5k
The sliding property under g load is more than 10 times smaller, the coefficient of dynamic friction is 0.08 to 0.15 smaller, and the sliding load is 16 to 30 g smaller, so it has a significant sliding property improvement effect. It could be confirmed.

In the same manner as in Example 3, an aluminum plate was subjected to surface treatment, then undercoated and top coated. However, the following acrylic resin paint having the following composition was used as the base for the top coat.

Melamine resin 6.9 Titanium dioxide 27.5 Butanol
3.0 Tsurupetutsu 150
10.0 The performance of the obtained precoated metal plate was as shown in Table 4.

Referring to Table 4 in the margin below, it can be seen that all sliding agents have the effect of improving sliding properties, as in the case of oil-free polyester.
The bendability was the same as that of 2T and a comparative example in which no sliding agent was added, and the coating film hardness and each sliding performance (Erichsen hardness tester 5 kg load web ring test, dynamic friction coefficient measurement,
The influence of the sliding agent is seen in the sliding load measurement and scratch resistance). Of each sliding performance, the Erichsen hardness tester's 5 kg load ubiquity is more than 10 times, and the coefficient of dynamic friction is 0.0.
7 to 0.14 is also smaller, and the sliding load is 15
The value was ~30g less, confirming a significant sliding property improvement effect.

As seen in the above experimental results, the addition of a sliding agent significantly improved the sliding properties, confirming its effectiveness.

Since there was a tendency to select sliding agents depending on the type of paint, the effectiveness ranking of paint types and sliding agents is shown below.

■ The effectiveness of sliding agents against vinylidene fluoride is better in the following order: tetrafluoroethylene, polyethylene, and polypropylene.

■ The effect of sliding agents on high-molecular polyester is best in the following order: polyethylene, polypropylene, > tetrafluoroethylene.

■ The effect of sliding agents on oil-free polyester is good for polyethylene, tetrafluoroethylene, and polypropylene.

■ The effect of sliding agents on acrylic is
Both tetrafluoroethylene and polypropylene are good.

〔Effect of the invention〕

As is clear from the above explanation, by adding each sliding agent to base resin paints such as vinylidene filleride, polymeric polyester, oil-free polyester, and acrylic according to the present invention, the sliding properties are significantly improved. Improved formability (roll and draw formability), quality, yield,
After commercialization, the design and functionality have been improved, and it can be widely used as building materials, home appliances, and fixtures.

Claims (1)

[Claims] 1. One or more types of polyolefin wax or perfluorocarbon resin wax having an average particle size of 7 to 40 μm.
A highly slidable precoated metal plate coated with a resin coating composition containing 0 to 10.0% by weight. 2. At least one type of polyolefin wax or perfluorocarbon resin wax with an average particle size of 7 to 40 μm.
0 to 10.0% by weight, and 0.01 to 0.0% by weight of silicone resin.
A highly slidable precoated metal plate coated with a resin coating composition containing 1% by weight.