JPH10237444A - Metal rust preventive - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a two-component rust preventive which retains its rust prevention effects for a long term even in a high-temp. high-humidity environment by causing a mixture comprising a thermoplastic resin and a nitrite to coexist with a mixture comprising a thermoplastic resin and an ammonia- or amine-based rust inhibitor. SOLUTION: A mixture (A) comprising at least one thermoplastic resin (e.g. a polyolefin resin, a copolymer resin such as an ethylene-vinyl acetate copolymer, a polyester resin, a polyamide resin, a copolymer rubber, or wax) and at least 0.1wt.% at least one nitrite is caused to coexist with a mixture (B) comprising at least one thermoplastic resin mentioned above and at least 0.1wt.% at least one ammonia- or amine-based rust inhibitor (e.g. ammonia benzoate, ammonium stearate, dicyclohexylamine phosphate, or benzotriazole).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a metal product for tropical
The present invention relates to a two-component metal rust preventive for storing various metal products that do not generate rust for a long period of time even when the metal products are packaged under bad conditions in which rust easily occurs in a high-temperature and high-humidity region such as a subtropical zone.

[0002]

2. Description of the Related Art Conventionally, before secondary processing of primary steel products, not only in Japan, but also for local production overseas, they are sent to the site through long days and transportation routes. Especially in the automotive industry, we supply parts from Japan to countries around the world,
Systems for assembling and producing locally are being actively used. Especially when transporting to rainforest areas such as Southeast Asia and storing products, the environment changes greatly,
Dew condensation easily occurred on the metal surface, causing rust. As described above, conventionally, rust is generated from the reaction between dew condensation water, oxygen, and metal, thereby deteriorating the product value and causing serious damage. In order to avoid such damages, measures have been taken to protect against rust by applying a large amount of rust-preventive oil directly to the metal product surface from the combination of "rust-preventive oil and packaging material". However, rust prevention with rust preventive oil is not always an effective means. When it comes to automotive parts, when coating sheet metal stamped products such as ceiling outer panels and door panels, rust preventive oil is washed and removed in a pretreatment process. . The degreasing agent solution used in the pretreatment process not only pollutes the working environment with unpleasant odor and oily odor, but also has high wastewater treatment cost and is inconvenient to handle.
In order to eliminate these problems, the development of a vaporizable rust inhibitor has been carried out. Typically, however, a combination of rustproof paper and packaging material impregnated in kraft paper, and a resin film coated with a vaporizable rust inhibitor A rust-preventive film formed by incorporating a rust agent
No. 47-4295, Japanese Patent Publication No. 53-2449) and various plastic films obtained by coating films with various vaporizable rust inhibitors together with other additives such as adhesives (Japanese Patent Publication No. 58-24270) Gazette). However, there is a limit to the amount of vaporizable rust inhibitor that can be contained in these packaging materials.
When wrapping a large space product such as a large metal product, if the area of the film wrapping the product is smaller than the space volume, not only will the vaporizable rust-preventive component from the rust-preventive film be diluted, Because of the high absolute water content, the concentration of the rust inhibitor in the condensed water was low, and a sufficient rust preventive effect could not be obtained.

Also, the use of a desiccant is effective only for a system completely sealed with a barrier wrapping material having a very high moisture resistance.
When packaging a large metal product, it is difficult to completely seal the product due to problems such as perforation due to the weight of the product and heat sealing properties, and the total cost is relatively high and the economy is poor. In addition, the desiccant that has lost its dehumidifying ability after several days may cause rust due to the release of absorbed moisture.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the problems which cannot be solved by the prior art, namely, the problems of post-washing due to contamination of the working environment and oil drop which are disadvantages of the rust preventive oil. It solves the problem of rust-proof packaging of metal products with a large space volume, which is difficult to handle with rust films and desiccants, and rust prevention for a long time under severe storage environment such as high temperature and high humidity environment. Retain the effect,
An object of the present invention is to provide a two-component metal rust inhibitor that does not impair the quality value of metal products due to rust.

[0005]

SUMMARY OF THE INVENTION The present invention provides a polyolefin resin such as high-density polyethylene, low-density polyethylene, linear low-density polyethylene, and polypropylene; a copolymer resin such as ethylene-vinyl acetate and acrylate; Copolymer rubber of two or more copolymer rubbers such as polyester resin, polyamide resin, ionomer resin, butene-1, pentene-1, hexene-1, etc. and other monomers, higher fatty acid ester Higher alcohol esters, ethylene, vinyl acetate copolymer waxes,
Animal and vegetable fats and oils, and at least one or more thermoplastic resins composed of ester waxes such as natural wax,
A mixture containing at least one kind of potassium nitrite, sodium nitrite, calcium nitrite, dicyclohexylammonium nitrite and diisopropylammonium nitrite in an amount of 0.1% by weight or more based on the thermoplastic resin [A], and ammonium benzoate; Alummonium phthalate, alummonium stearate, ammonium palmitate, ammonium oleate, ammonium carbonate, dicyclohexylamine phosphate, dicyclohexylamine benzoate, urea, urotropin, thiourea,
Phenyl carbamate, benzotriazole, 4-methylbenzotriazole, 5-methylbenzotriazole, 5-
Nitrobenzotriazole or 3-methyl-5-pyrazolone is used in an amount of at least one kind selected from the above-mentioned thermoplastic resins.
The blend containing not less than 1% by weight is melt-kneaded and extruded on a solid to form a mixture [B]. The mixture [A] and the mixture [B] are mixed without mixing. The above problem was solved by coexisting in an appropriate shape in a sealed space in which metal products requiring rust are stored.

Further, in the present invention, the mixture [A] and the mixture
200 g of a two-component metal rust inhibitor consisting of [B]
/ m ²・ 24hr or more, Gurley-type air permeability 5,000 seconds / 100cc or less Therefore, by storing this in a sealed space together with a metal product, it is possible to prevent scattering due to impact at the time of transportation, and furthermore, the above-mentioned packaging material having a function of ventilation, moisture permeability and waterproofness is a mixture [A]. Thus, the deliquescent solution of the two-component rust preventive made of the mixture [B] after moisture absorption is separated from the metal product, and can be stored without deteriorating the value of the metal product, thereby solving the above problem.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The thermoplastic resins used in the present invention include high-density polyethylene, low-density polyethylene, linear low-density polyethylene, polyolefin resins such as polypropylene, and ethylene / vinyl acetate and acrylic acid esters. Copolymer resin, polyester resin, polyamide resin, ionomer resin, butene-1, pentene-1,
Copolymer rubbers of two or more copolymer rubbers of α-olefins such as hexene-1 and other monomers,
Examples include higher fatty acid esters, higher alcohol esters, ethylene / vinyl acetate copolymer waxes, paraffin waxes, and waxes such as natural waxes. In each case, the mixture [A] was prepared by mixing at least one of potassium nitrite, sodium nitrite, calcium nitrite, magnesium nitrite, dicyclohexylammonium / nitrite or diisopropylammonium nitrite with respect to the thermoplastic resin.
More than 0.1% by weight, preferably 10 to 60% by weight of the thermoplastic resin is mixed with the thermoplastic resin and the nitrite powder is mixed, or the nitrite is added to the surface of the pellet-like thermoplastic resin. Or dispersing the above-mentioned nitrite in a solvent such as methanol, coating a solid thermoplastic resin surface layer, and evaporating and drying the solvent to obtain a mixture [A]. is there. Examples of a method for mixing the above components include kneading with a Banbury mixer, a mixing roll kneader, a single screw extruder, a twin screw extruder, or the like. The mixture [A] is desirably adjusted to a maximum diameter of 30 mm or less in order to increase the contact area with air in the system in which the metal product is packaged.

[B] is ammonium benzoate, ammonium phthalate, ammonium stearate, ammonium palmitate, ammonium oleate, ammonium carbonate, dicyclohexylamine phosphate, dicyclohexylamine benzoate, urea, urotropin, thiourea, Phenyl carbamate, benzotriazole,
0.1% by weight or more, preferably 10 to 50% by weight, based on the thermoplastic resin, of at least one kind of 4-methylbenzotriazole, 5-methylbenzotriazole, 5-nitrobenzotriazole or 3-methyl-5-pyrazolone A blend is prepared. As a method of molding the blend into a solid state, thermoplastic resin pellets, kneading means suitable for powder and the like, for example, a Banbury mixer, a mixing roll kneader, a single screw extruder, a heating and melting by a twin screw extruder or the like. There are a method of pelletizing the kneaded and extruded mixture with a pelletizer, a method of processing the mixture on a sheet, and cutting the mixture. In any case, the rust-preventive additive used in the mixture [B] is an ammonia- or amine-based rust-preventive additive, which has a high vapor pressure and is easily vaporized and disappears. If the melting point is high, the blend tends to evaporate when it is molded on a solid, but it can be used without any problem if the melting point of the thermoplastic resin is about 120 ° C. or less. It has been found that when both the mixture [A] and the mixture [B] are mixed together in powder form, they disappear early and the effect is reduced by half. Therefore, [B] is desirably adjusted to a solid having a minimum diameter of 1 mm or more in order to reduce the contact area with air in the atmosphere.

In a closed system in which metal products are packaged, nitrite having a large hygroscopic effect in one of the mixtures [A] and [B] absorbs moisture first near a relative humidity of 75% RH. Since it deliquesces at the beginning, the amount of water decreases and the dew condensation phenomenon hardly occurs.
In addition, by increasing the concentration of nitrite in the mixture [A] and increasing the total amount, it is possible to further reduce the amount of water in the closed system in which the metal product is packaged, and it is difficult for the dew condensation phenomenon to occur and the environment to be resistant to rust. Is formed. Next, the rust preventive agent in the mixture [A] that has been deliquescent and changed to a liquid state permeates the mixture [B] formed into a solid state, and is in a state where it easily reacts with each other. Since the rust-preventive additive of the mixture [B] is of an ammonia or amine type, it has a high vapor pressure and is easily vaporized and disappears. Therefore, the mixture [B] can be brought into contact with the deliquescent and liquefied mixture [A]. Become. Therefore, the mixture [A] and the mixture [B] do not necessarily need to be mixed so as to be adjacent to each other. The mixture [A] and the mixture [B] having appropriate shapes are allowed to coexist in a closed system in an appropriate ratio, and the mixture [ B] can be brought into contact with the liquefied mixture [A] deliquescent and stored in a small bag or small container, which makes it possible to prevent rust during long-term transport and storage of metal products. Further, the mixture [A] and the mixture [B] can coexist in a closed system by dispersing and coating a water-soluble liquid obtained by dissolving the mixture [A] in water on the surface layer of the mixture [B].

The concentration of the chemicals contained in the mixture [A], [B] can be sufficiently achieved if the concentration is 0.1% by weight or more. Particularly, [A] is prevented from being contained in the thermoplastic resin. When the concentration of the rusting agent is 0.1% by weight or less, the contact with the mixture [B] becomes difficult because the rusting agent does not change to a liquid state. On the other hand, when the concentration of the rust preventive additive to be contained in the mixture [B] is 80% or more, solid molding becomes difficult. The coexistence ratio of the mixture [A] and the mixture [B] may be such that the weight ratio of the mixture [A] to the mixture [B] is in the range of 1: 6 to 6: 1, and preferably 1: 2 to 6: 1. The rust prevention purpose can be achieved at 2: 1. In the present invention, by using different types of rust-preventive compounds for the mixture [A] and the mixture [B],
Metal products made of other metals can be protected from rust. For example, as the nitrite to be mixed with the mixture [A], dicyclohexylammonium / nitrite, which has a high rust-preventing effect on irons, is used. It was confirmed that when a benzotriazole having a high value was selected, the effect was exhibited not only on steel but also on rust prevention of composite metal products with aluminum. In particular, in a hydrolysis reaction in a packaged system that occurs in a combination of the chemicals contained in the mixture [A] and the mixture [B], a subunit effective for the rust-preventive effect, such as a mixed system of sodium nitrite and urotropin, is obtained. Since a reactive gas such as ammonium nitrate is generated, it has a synergistic effect on rust prevention of irons.

When a two-component metal rust inhibitor consisting of the mixture [A] and the mixture [B] is used, the water vapor transmission rate (JIS Z 0208) value is 200 g / m ² · 24 hours or more. Consisting of
Gurley type air permeability (JIS P 8117) value is 5,000 seconds / 100 cc or less By storing in a small bag or small container of breathable and moisture-permeable film, the vaporization of rust preventive additive affected by environmental temperature Even if the rust preventive itself, which is affected by speed and environmental humidity, has hygroscopicity, rust prevention of metal products has become possible.

Next, the rust prevention test method performed in the present invention using the metal rust preventives of Examples 1 to 4 and the mixtures of Comparative Examples 1 to 5 will be described.

[Rust prevention test method] First, four kinds of test pieces (Table 1) were hung in a basket having a large volume of 100 × 150 × 100 cm, and the metal rust preventives of Examples 1 to 4 and Comparative Example 1 were used. Place the mixture of ~ 5 in the center of each basket. Put these baskets in a 100 μm polyethylene film bag, heat seal and seal,
It was left under the test conditions (a). By repeating the temperature and humidity of the test conditions, an environment in which the test surface easily condenses was created, and the difference in effects over a long period (60 days) was evaluated according to the evaluation criteria (b). The test pieces shown in Table 1 were used after washing with solvent naphtha and air drying.

(A) Test environment 25 ° C, 70% RH: 4 hours 50 ° C, 95% RH: 4 hours Set transfer time: 2 hours, total 12 hours / cycle

[0015]

[Table 1]

(B) Evaluation Criteria ：: No rust and discoloration 点: Spot rust and slight discoloration occurred Δ: Rust or discoloration occurred less than 10% based on test specimen area ×: 10 relative to test specimen area Rust or discoloration occurs in less than ~ 50% XX: Rust or discoloration occurs in 50% or more of the test piece area

[0017]

Example 1 Low-density polyethylene powder (Sumitomo Seika Co., Ltd.)
28% by weight of sodium nitrite powder to obtain a mixture [A]. Also low density polyethylene powder
(Sumitomo Chemical Co., F218-1, density 0.919) was mixed with 10% by weight of urotropin, melt-kneaded at 135 ° C with a twin-screw extruder, cooled, and formed into a solid having a diameter of 5 mm and a length of 10 mm. And mixture [B]. Mixing ratio of binary metal rust preventive consisting of mixture [A] and mixture [B] in weight ratio of mixture [A]: mixture
[B] = 2: 3, a total amount of 5 g was placed in a petri dish, and used for a rust prevention test. Table 2 shows the results of the evaluation test.

[0018]

Example 2 Ethylene / vinyl acetate copolymer pellets (manufactured by Sumitomo Chemical Co., Ltd.) were mixed with 20% by weight of dicyclohexylammonium nitrite to obtain a mixture [A].
And Also, 5% by weight of benzotriazole was mixed with polyethylene wax powder (PF520, manufactured by Hoechst), melt-kneaded at 105 ° C. with a twin-screw extruder, cooled, molded into a solid having a maximum diameter of 5 mm, and the mixture [ B]. Mixture [A]
The mixture ratio of the two-component metal rust preventive consisting of the mixture [B] and the mixture [B] was 3: 2 in the mixture [A]: mixture [B] = 3: 2, and a total amount of 10 g was placed in a petri dish and used for a rust prevention test. Table 2 shows the results of the evaluation test.

[0019]

Example 3 10 g of a two-component metal rust inhibitor according to Example 2
The water vapor permeation amount (JIS Z 0208) value, 5000 g / m ² · 24 hr or, Gurley ShikiToru air permeability (JIS P 8117) value 500 sec / vent-breathable film consisting of 100 cc (Ltd.) Tokuyama) bag (10 × 10cm) and used for the rust prevention test. Table 2 shows the results of the evaluation test.

[0020]

Example 4 Low-density polyethylene powder (Sumitomo Seika Co., Ltd.)
50% by weight of sodium nitrite powder to obtain a powder mixture [A]. 5% by weight of benzotriazole was mixed with an ethylene-methyl acrylate copolymer resin (RB4120, manufactured by Nippon Oil Co., Ltd., density: 0.934), melt-kneaded at 105 ° C by a twin-screw extruder, and cooled to a maximum diameter.
The mixture was molded into a solid of 25 mm to obtain a mixture [B]. blend
The mixture ratio of the binary metal rust inhibitor consisting of [A] and mixture [B] was set to mixture [A]: mixture [B] = 2: 3, and the total amount was 10 g.
Water vapor permeation amount (JIS Z 0208) value, 5100g / m ² · 24hr,
Gurley-type air permeability (JIS P8117) A bag of a breathable and moisture-permeable film (Tokuyama Corporation) with a value of 50 seconds / 100 cc (10 ×
10cm) and used for the rust prevention test. Table 2 shows the results of the evaluation test.

[0021]

Comparative Example 1 Only 3 g of the mixture [B] used in Example 1 was placed in a petri dish and used for a rust prevention test. Table 2 shows the results of the evaluation test.

[0022]

Comparative Example 2 Sodium sulfite powder used in Example 1
1.2 g and urotropican powder 200 mg (the same amount of pure reagent as in Example 1) were placed in a petri dish and used for a rust prevention test. Table 2 shows the results of the evaluation test.

[0023]

Comparative Example 3 Mixture [A] and Mixture Used in Example 1
2 g of the binary metal rust inhibitor consisting of [B] and 2 g of the mixture [B] (weight ratio 1: 2) were placed in separate petri dishes and used in a rust prevention test. Table 2 shows the results of the evaluation test.

[0024]

[Comparative Example 4] 10 g of a two-component metal rust inhibitor of Example 2
The water vapor transmission rate (JIS Z 0208) value is 3g / m ² · 24hr, Gurley air permeability (JIS P 8117) value is 50,000 seconds / 100cc
Small bag of high-density polyethylene film (10 ×
10cm) and used for the rust prevention test. Table 2 shows the results of the evaluation test.

[0025]

Comparative Example 5 Mixture [A] and Mixture [B] of Example 2
The mixture ratio was set as mixture [A]: mixture [B] = 5: 100, and a total of 5 g of the water vapor transmission amount (JIS Z 0208) value was 5100 g /
m ² · 24 hr or, Gurley ShikiToru air permeability (JIS P 8117) value, 50 sec /
100cc air-permeable and moisture-permeable film (Tokuyama Corporation)
And stored in a small bag (10 × 10 cm) for rust prevention test.
Table 2 shows the results of the evaluation test.

Table 2 shows the test results of this evaluation.

[Table 2]

As is clear from Table 2, even under the condition where dew condensation occurs, the coexistence of the mixture [A] and the mixture [B] can prevent the generation of rust for a long period of time. Rust prevention packaging becomes possible. Even if a molded product of the mixture [A] and the mixture [B] is stored in a small bag or a small container of a gas-permeable / moisture-permeable film, the desired rust prevention effect can be obtained.

As described above, the embodiments of the present invention have been described in detail. The present invention is not limited to the above embodiments, and various design changes may be made without departing from the present invention described in the appended claims. It is possible.

[0029]

As described above, the present invention solves the conventional problems of rust-preventive packaging of metal products, and maintains the rust-preventive effect for a long period of time under severe conditions of storage such as high temperature and high humidity. Therefore, it is possible to obtain a metal rust preventive which does not impair the quality value of the metal product and is easy to handle.
Further, by storing a two-component metal rust preventive agent as described in the claims in a small bag or small container of a breathable and moisture-permeable film, and coexisting with the metal product, the value of the metal product is impaired. Nothing.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI C23F 11/18 C23F 11/18

Claims (4)

[Claims] 1. A two-component metal rust inhibitor comprising the following [A] and [B]. [A]; at least one or more of polyolefin resins such as polyethylene and polypropylene, copolymer resins such as ethylene vinyl acetate and acrylic acid ester, polyester resins, polyamide resins, ionomer resins, rubber resins and waxes. For thermoplastic resins,
A mixture containing at least one of potassium nitrite, sodium nitrite, calcium nitrite, magnesium nitrite, dicyclohexylammonium nitrite or diisopropylammonium nitrite in an amount of 0.1% by weight or more. [B]; with respect to at least one or more thermoplastic resins comprising the thermoplastic resin shown in the above [A], ammonium benzoate, ammonium phthalate, ammonium stearate, ammonium palmitate, ammonium oleate, ammonium carbonate, Dicyclohexylamine phosphate, dicyclohexylamine benzoate, urea, urotropin, thiourea, phenyl carbamate, benzotriazole, 4-methylbenzotriazole, 5-methylbenzotriazole, 5-nitrobenzotriazole or 3-
A mixture containing at least one kind of methyl-5-pyrazolone in an amount of 0.1% by weight or more. 2. The mixture [A] and the mixture [B] coexist by dispersing and coating the surface layer of the mixture [B] with an aqueous solution obtained by dissolving at least one or more nitrites in the mixture [A] in water. The two-component rust inhibitor according to claim 1, wherein: 3. The two-component rust inhibitor according to claim 1, wherein the coexistence ratio of the mixture [A] and the mixture [B] is in the range of 1: 6 to 6: 1 by weight. 4. A bag or small container of a gas-permeable and moisture-permeable film having a water vapor transmission rate of 200 g / m ² · 24 hr or more and a Gurley-type air permeability of 5,000 seconds / 100 cc or less, according to any one of claims 1 to 3. A metal rust inhibitor containing two two-component rust inhibitors.