JPS61195980A - Material for rust prevention of metal - Google Patents

Abstract

PURPOSE:To obtain a material for rust prevention effective in the rust prevention of metal fixing the powdery grains of a water-absorbable polymer on a sheet. CONSTITUTION:A material for the rust prevention of metal is formed by fixing the powdery grains of a water-absorbable polymer by a binder or the like on a sheet. Still more as the water absorbable polymer, a polymer having the water absorption capacity of about >=20 times for the own weight is used and self-crosslinking polyacrylate is preferable. As the sheet, the material thereof is not especially limited and when a vapor phase inhibitor such as dicyclohexyl ammonium nitrite is coated, further excellent rust proof effect is exhibited.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a material used for rust prevention of metals such as metal products and metal plates. More specifically, the present invention relates to a rust-preventing material for metals that can prevent rust from coming into contact with water by preventing moisture in the air from condensing.

[Conventional technology and problems]

Metals cannot avoid rust and corrosion in corrosive environments. As a basic measure to prevent corrosion (including rust), it is best to apply oil or anti-rust oil or paint to the metal surface.

However, when it comes to steel products or secondary products, consumers often process them in the next step to make them into products. Normally, processors had to wipe off the oil and anti-corrosion oil once applied, which took a lot of effort. For example, when it comes to automobile parts, sheet metal press parts such as ceiling panels, door panels, fender panels, floor panels, etc. are coated with anti-rust oil, and after the above press parts are welded and assembled as a car body, before painting. Rust preventive oil was washed away during the treatment process. However, anti-rust oil is difficult to remove, requires a strong degreaser, is expensive, and is difficult to handle.

Therefore, as an alternative to the method of applying oil or anti-corrosion oil and then wiping off the oil, vaporizable rust and corrosion inhibitors have been developed and are now widely used. Advances in rust and corrosion inhibitors have reduced the need for wiping and cleaning.

Volatile rust-preventing and corrosion-inhibiting agents are usually applied to paper, and the object to be rust-prevented is wrapped in paper coated with the volatile rust-preventing and corrosion-inhibiting agent. However, it is difficult to protect objects to be rust-prevented from rusting for a long time in a high-humidity atmosphere. for example,
When storing and transporting small equipment such as watches and measuring instruments during the rainy season, even if the small equipment is wrapped in paper coated with the above-mentioned volatile rust and corrosion inhibitor, the vaporized rust and corrosion inhibitor will not enter the equipment. Situations that occur frequently cause rust to occur.

The same applies to the storage and transportation of movable iron and fixed iron, where even the slightest amount of rust must be avoided.Furthermore, primary cracked products such as coils made from rolled steel strips must be stored and transported. When exporting for a long time, in a humid atmosphere, and in places where there are temperature differences between night and day, condensation tends to occur, and even if a volatile rust preventive agent protects the metal surface, it will be washed away little by little by the condensed water. , Rust may occur due to repeated condensation water.

[Means for solving problems]

In order to solve this problem, the present inventors made extensive research efforts and found that a structure obtained by fixing water-absorbing polymer powder to a sheet can prevent dew condensation on the object to be rust-prevented. I discovered that it is something.

That is, the present invention aims to provide a rust-preventing material for metal, which includes a water-absorbing polymer powder and a sheet as essential components, and the water-absorbing polymer powder is fixed onto the sheet. .

In the present invention, the water-absorbing polymer powder can be fixed to a sheet by, for example, using an adhesive, or by using a thermoplastic film for the sheet and softening the thermoplastic film by applying heat to the sheet. There is a method of compressing water-absorbing polymer powder and embedding it. Furthermore, there is also a method of sandwiching the water-absorbing polymer powder between sheets.

In this case, part of the sheet needs to be air permeable. This is because high-humidity air passes through the breathable sheet,
This is because it is necessary to be able to come into contact with the water-absorbing polymer powder. When the water-absorbing polymer is held between sheets, the sheets may be formed into a bag, and the water-absorbing polymer powder may be placed in the bag. In this case, the sheet used for the bag does not necessarily have to be air permeable, as long as air can pass in and out between the inside and outside of the bag. In addition, when the water-absorbing polymer is sandwiched between sheets, at least one sheet is air permeable, and the sheets are overlapped and adhered, and the adhesion is performed in a number of ways to form a large number of bags. It is preferable to apply the adhesive in a linear manner, for example, in the form of a base pattern, so that the water-absorbing polymer powder is contained in each bag in which the sheet and the sheet are to be formed.

In addition to the water-absorbing polymer powder and sheet described above, other materials may be used in combination with the metal rust-preventing material of the present invention.

For example, a volatile rust inhibitor may be used in combination. One way to use them in combination is to apply a volatile rust preventive to the sheet. In this case, it is convenient to use commercially available anti-rust paper coated with a volatile anti-rust agent as the sheet. If the volatile rust preventive agent is in the form of powder or granules, it may be fixed to the sheet in the same way as or at the same time as the water-absorbing polymer powder.

The water-absorbing polymer powder used in the present invention can be obtained by pulverizing a water-absorbing polymer, or by a method such as suspension polymerization or emulsion.

The water-absorbing polymer used in the present invention is a substance that absorbs a large amount of water when it comes into contact with water, and has a water-absorbing capacity of 20 times or more its own weight. For example, 4! Tempe-polyacrylonitrile graft copolymer disclosed in Japanese Patent Publication No. 49-45595, cross-linked polyalkylene oxide disclosed in Japanese Patent Publication No. 51-39672, Japanese Patent Publication No. 55
Saponified vinyl ester-ethylenically unsaturated carboxylic acid copolymer disclosed in Japanese Patent Publication No. 13495, etc., and self-crosslinked polystyrene obtained by the reverse phase suspension polymerization method disclosed in Japanese Patent Publication No. 54-30710, etc. acrylic acid salts, reaction products of polyvinyl alcohol-based polymers and cyclic anhydrides disclosed in JP-A-54-20093, etc.;
Examples include crosslinked polyacrylates disclosed in JP-A-55-84304 and the like. Among these, crosslinked polyacrylates are preferred, and self-crosslinked polyacrylates obtained by reverse-phase suspension polymerization exhibit excellent effects8. The reason for this is that it has a large water absorption capacity, which is several U times its own weight. In particular, when condensation water that repeatedly occurs flows down the metal surface and accumulates below, causing rust on the metal, cross-linked polyacrylic acid, which has a large water absorption capacity, is used. The salt is
It effectively protects metal from rusting.

In particular, self-crosslinking polyacrylates obtained by reverse-phase suspension polymerization are particularly excellent. The reason for this is that the crosslinked polyacrylate obtained by the reverse phase suspension polymerization method is an extremely uniform powder and granule, and there is no need for a step of pulverizing it into powder and granules. This is because it is convenient for manufacturing such antirust materials.

Since the sheet used in the present invention supports the water-absorbing polymer powder, the sheet may be hard or hard, porous or non-porous, and the material may be used. isn't it. Therefore, in addition to paper, knitted fabrics, woven fabrics, etc., synthetic resin films such as polyethylene, polypropylene, polystyrene, polyester, polyamide, polyvinyl chloride, polyolefin, etc. are often used, and even rubber sheets and metal foils can be used. It's not a hindrance. Since the air-permeable sheet used in the present invention constitutes a rust-preventing material by sandwiching water-absorbing polymer powder, it may be a porous sheet with holes large enough to allow air containing water vapor to pass through. It is widely available. Therefore paper,
- Goods, textiles, porous synthetic resin films, etc. will be prized.

Volatile rust inhibitors used in the present invention include, for example, dicyclohexyl ammonium nitrite, a mixture of monoethanolamine benzoate, urea and sodium nitrite, diisopropylammonium nitrite, dicyclohexylamine cabrylate, cyclohexylamine carbamate, 80% dicyclohexyl Mixtures of ammonium nitrite and 20% diisopropylammonium nitrite, carboxylate salts of amines, cyclohexylammonium carbonate, benzo)IJ azoles for copper and copper alloys, and others known in the art may be used.

〔Effect of the invention〕

Since the metal rust-preventing material according to the present invention is in the form of a sheet, it can also be used as a packaging material, and may be put into use as a sheet in a narrow space inside a sealed package.

The rust prevention material for metals according to the present invention can be used for all metals that are commonly used as materials, such as iron, aluminum, copper, or alloys thereof, which cause rust or skin erosion when they come into contact with water. . Metals that are subject to rust prevention include steel plates, copper strip coils, wire rods, small equipment, etc.
It can be used to prevent rust on all metals, and can be used as a packaging material or as a sheet to be inserted into narrow spaces, depending on the purpose of the machine, instrument, product, etc., such as precision equipment.

Furthermore, by using an air-permeable sheet coated with a vaporizable rust preventive agent, the vaporizable rust preventive agent directly protects the metal surface, and the absorbent polymer absorbs as much moisture as possible. Therefore, both of them work together to provide even better rust prevention effects.

〔Example〕

The present invention will be explained below with reference to Examples, but the present invention is not limited to these Examples.

Example 1 After making an aOZ airtight container into an atmosphere of 50C, 9B% relative humidity, a water-absorbing polymer (Special Public H54) was placed in a small bag made of Japanese paper.
- self-crosslinking polyacrylate of Example 1 of say1a)
10I was inserted, and thereafter, changes in humidity within the container were measured over time.

The results are shown in Table 1.

Table 1 Relative humidity (%) Example 2 A water-absorbing polymer (polyacrylic acid granules with a particle diameter of 30 to 100μ by the method of Example 1 of JP-A No. 1155-74!509) was applied to 20cIIIX30cIR packaging paper impregnated with 0 ) 59 was dispersed, the paper was divided into sections, adhesive was applied on the packaging paper in a lattice pattern, Japanese paper was placed on top of the paper, and a water-absorbing polymer was sandwiched between the sheets to form a sheet. I folded this sheet so that the Japanese paper side was on the inside and wrapped it around the metal piece.

The test metal pieces were commercially available cold-rolled steel plates and copper plates (60 x a
(o, s) were soaked in hexane, wiped off and washed thoroughly.

Six test pieces each were wrapped in polymer-free and polymer-added sheets and stored in a constant temperature and humidity chamber at a temperature of 80C and a humidity of qac for one week.

Rust was evaluated using the foundation method (JIS Z-2912). The results are shown in Table 2. The numerical values indicate the rate of rust occurrence, and the higher the numerical value, the worse it is, and the maximum value is 100.

Table 2 Example 3 Comparative Kume commercially available anti-rust J abrasive (LL manufactured by Kanzaki Rigami Co., Ltd., -35-
Using dicyclohexylamine as a volatile rust preventive agent, a 0.1% hexane solution of dicyclohexylamine was applied to the rust preventive sheet of Example 2 using a sprayer.
This product was sprayed and dried to produce a rust preventive sheet with a vaporized rust preventive agent.

Then, to prevent the metal test pieces whose rust rate was investigated under the following storage conditions from being directly immersed in the added water, a stand with a height of 5 cWI was installed and an airtight 9! A synthetic resin container (30 x 30 x 10 cm) was used. Hot water 10011 in that container
4 (more than 80 r), and the test steel pieces wrapped with the rust prevention sheet and 6 pieces of commercially available rust prevention paper were placed on a stand.
Immediately put the lid on and seal it with duct tape.

The container was left in a place exposed to direct sunlight during the day for 7 days so that dew condensation occurred every day. The temperature inside the box ranged from a maximum of 30C to a minimum of 5C. Table 5 shows the results of measuring the rusting rate in the same manner as in Example 2.

Table 3 Example 4 As shown in Fig. 1, rayon paper C containing 30% polyethylene, basis weight 301/Ill'), starch
Saponified acrylonitrile 2/30JI7711' was sprayed and heated to produce a rust preventive material.

Example 5 As shown in Figure 2, sodium polyacrylate 2' was added to 2597N2 rayon paper 1' containing 20% polyethylene.
Then, starch paste was applied to Japanese paper 5, and the paste was overlapped and bonded to produce a rust preventive material.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the invention, and FIG. 2 is a sectional view showing another embodiment of the invention. 111'...Rayon paper 2, z...Water-absorbing polymer powder 3...Japanese paper

Claims (1)

[Scope of Claims] 1. A rust-preventing material for metal, which includes a water-absorbing polymer powder and a sheet as essential components, and the water-absorbing polymer powder is fixed onto the sheet. 2. For rust prevention of metal according to claim 1, wherein the sheet is composed of two or more sheets, at least one of which is air permeable, and water-absorbing polymer powder is sandwiched between the sheets. material. 3. The rust-preventing material for metals according to claim 2, wherein the air-permeable sheet has a volatile rust-preventing agent coated on its surface.