JPH0362838B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to packaging materials for metals. More specifically, the present invention relates to a rust-proof packaging material for effectively preventing metals from rusting during packaging. Generally, metal products are packaged for transportation, storage, etc. after manufacture until they are used by the user. During this time, it is necessary to prevent rust and maintain the quality of the product, especially when packaging products for export. The issue of rust prevention is important. Conventionally, various techniques have been proposed for blocking atmospheric moisture and oxygen from metals to be packaged for the purpose of rust prevention. For example, the surface of the metal to be packaged is coated with oil by immersing the metal product in anti-corrosion oil or spraying the same onto the surface, thereby shielding it from moisture and air (oxygen). How to cover metal surfaces with plastic and peel it off during use, PE laminated paper, Al laminated paper,
Methods of moisture-proof packaging using packaging materials such as PE bags or desiccants such as silica gel, methods of using a powdered volatile rust preventive agent in sealed packaging, methods of impregnating or coating paper with a volatile rust preventive agent. A method using rust-proof paper is known. However, in the method of using anti-corrosion oil, the surface of the metal to be packaged becomes sticky, and the user must remove it by washing before use, which is troublesome and time-consuming. Furthermore, some products are not suitable for oil immersion or oil spraying, and some products do not want to be contaminated with oil. Furthermore, even with techniques that use other desiccants and rust preventives, packaging operations become complicated and costs increase. Furthermore, in addition to the above methods, wooden boxes, cardboard boxes, and the like have been used as packaging materials, but these only promote the formation of rust. So far, little is known about the effects of paper, paperboard, and cardboard, which have traditionally been used as packaging materials, on the rusting of metals as packaging materials. In view of these circumstances, the inventors of the present invention have conducted various studies to develop simple and inexpensive anti-rust packaging materials. By using products obtained by processing and removing harmful gas components that promote rusting of metals, metal articles to be packaged, especially the parts that do not come into contact with the packaging material (non-contact parts), can be prevented from forming. The present invention was completed based on the discovery that rust can be effectively inhibited. SUMMARY OF THE INVENTION Therefore, the main object of the present invention is to provide a novel anti-rust packaging material which has a rust-preventing effect on metals as packaged articles, especially the parts that do not come into contact with the packaging material. The above and other objects and features of the present invention will become apparent from the following description. That is, the present invention provides paper as a packaging material for metals,
When the gas generated when paperboard or cardboard is heated at 80℃ for 60 minutes under a pressure of 10 mmHg or less is analyzed using a gas chromatograph equipped with a flame photometric detector under the following conditions. , a component whose retention time is detected as 0.60 to 0.65 compared to the retention time of methyl mercaptan as an internal standard, or a component detected as 0.46 to 0.51 compared to the retention time of methyl sulfide as an internal standard. The composition is characterized by having a sulfur content of 0.02μg/g paper or less, and controlling rusting of metals.
The above relates to paperboard or cardboard. The conditions are as follows. Separation tube filling: Brown diatomaceous earth separation tube coated with triscyanoethoxypropane Temperature: 100℃ The new anti-corrosion packaging material according to the present invention is for packaging steel products such as steel plate coils and cut plates; packaging for knockdown for export; made of metal , Especially packaging of mechanical parts (various parts, repair parts) made of steel and copper; various connectors,
It can be advantageously used for packaging electronic components such as switches and IC lead frames; other metal products other than iron, such as products made of silver, copper, etc., or products plated with these metals, and is expected to provide effective rust prevention. can do. It should be understood that the metal products described above are merely examples, and that other metal products are also applicable. The rust-proof packaging material of the present invention is a corrugated liner,
It includes not only core or general packaging paper but also all paper and paperboard used for packaging metals, and whether or not it contains sulfur or other components that have a harmful effect on the metals being packaged. I don't care.
Those containing such harmful components can be modified to have a rust-preventing effect, especially in the areas that do not come into contact with the packaging material of the packaged product, by subjecting them to special treatment as detailed below. The pulp used in the paper making of the packaging material of the present invention is not particularly limited, and any pulp can be used, such as those digested by the kraft method, sulfite method, soda method, soda carbonate method, etc., or waste paper pulp. Among them, pulp cooked using a cooking liquor that does not contain sulfur, such as the soda method or the soda carbonate method, is preferable. Further, when cooking the pulp other than waste paper pulp, it is also possible to add a quinone-based cooking aid and/or a penetrating agent to the cooking liquor. As the quinone-based cooking aid, for example, anthraquinone, 1,4-dihydro-9,10-dihydroxyanthracene, anthrahydroquinone, etc. can be used, and there are no particular limitations. Furthermore, examples of the penetrating agent include polyalkylene oxide polymers, and these are not particularly limited. Therefore, the pulp that can be used in the present invention includes not only sulfur-free alkaline pulp, but also
This includes thermomechanical pulp (TMP) and unbleached kraft pulp (UKP), which has been heat-treated or oxidized to remove harmful components. Such pulp is used as a raw material, and after being pre-milled, selected, and beaten according to conventional methods, it is made into paper. Paper making can be carried out in an acidic region by adding aluminum sulfur to the pulp slurry as usual, but it is more preferably carried out in a neutral region of pH 6 to 8. During papermaking, paper strength agents, sizing agents, etc. can be added as raw material preparation chemicals.For papermaking in an acidic region, these conventionally known chemicals can be used as they are, while for papermaking in a neutral region. Since aluminum sulfate cannot be used, self-fixing paper strength agents such as Mannitz- or Hoffman-modified polyacrylamide or polyamide polyamine, cation-modified starch, etc. are used as paper strength agents.
Also, as a sizing agent, alkyl ketene dimer,
Alkenyl succinic anhydride, rosin higher fatty acid polyamine, petroleum resin maleide polyamine, etc. are used. The packaging material of the invention thus obtained can be used as is or after further processing. Furthermore, by coating the surface of the packaging material with a chemical having a rust-preventing effect, it is possible to obtain a packaging material for metals that has an even more excellent rust-preventing effect. Examples of the agent having an antirust effect include salts of organic acids and inorganic acids, such as sodium salts, potassium salts, and ammonium salts of benzoic acid, nitrous acid, and phosphoric acid, and among them, sodium salts are preferred. These chemicals having a rust-preventing effect are applied to paper alone or together with starch, polyvinyl alcohol, etc. Hereinafter, the method for manufacturing the packaging material of the present invention that satisfies the above conditions will be explained in more detail. According to one embodiment of the production method, a lignocellulosic material is pulped with a cooking liquor that does not contain sulfur compounds to obtain sulfur-free pulp, and the pulp thus obtained is made into paper to obtain the desired packaging material. The cooking liquor that does not contain yellowing compounds used in this embodiment is caustic soda alone, carbonate soda alone, a mixture of caustic soda and soda carbonate, or a quinone-based cooking aid and/or penetrant is added to these cooking liquors. As the cooking aid and penetrating agent, those mentioned above can be used. The pulp produced by the above-mentioned pulping method does not contain harmful gas components, and the harmful gas components do not increase in the subsequent steps regardless of whether the paper making method is an acid paper making method or a neutral paper making method. Furthermore, the amount of harmful gas components does not change depending on whether or not a chemical having a rust-preventing effect is applied to the paper. Therefore, pulp obtained by pulping lignocellulosic materials with cooking liquor that does not contain yellowing compounds, or paper, containers, etc. made from this pulp, must be used to prevent rusting of packaged items, especially rusting of non-contact parts. It has a remarkable effect. In addition, by making the pulp of this embodiment into a neutral paper and further applying a chemical having a rust-preventing effect, it is possible to prevent rusting at the contact area, and this effect can be seen in the second and third conditions shown below. The same can be obtained in other embodiments as well. According to the second aspect of the method for producing a packaging material of the present invention, the pulp obtained by the method described in the general production method above, the paper obtained by papermaking the pulp, or the container produced from this paper is heated. By processing, the desired packaging material can be obtained. In this embodiment, harmful gas components can be removed by heat-treating the pulp, paper, or container at any stage, and the effect on non-contact parts is the same as in the first embodiment. , it is not affected by conditions such as the paper-making method or the application of anti-rust agents before and after the process. The heat treatment in this embodiment is most preferably carried out in a nitrogen stream, but it may also be carried out in a normal heat treatment apparatus. Heating at low temperatures or for a long period of time is not preferable because it may damage the fibers, and at low temperatures it takes a long time to remove harmful gas components that are factors for rusting.
Therefore, the heat treatment that can usually be performed is in the temperature range of 60 to 150℃.
°C, time is 1-5 days. Furthermore, according to a third aspect, the intended packaging material is produced by pulping the ligated cellulose material with a cooking liquor containing a sulfur compound, and then oxidizing the pulp or oxidizing paper made from the pulp. can be obtained. In this embodiment, harmful gas components can be removed by performing oxidation treatment on either the pulp or paper, and the effect on non-contact areas depends on the papermaking method before and after that, as in the above embodiment. It is not affected by conditions such as the application of a chemical that has an anti-rust effect. Various compounds can be used as the oxidizing agent in this embodiment, but water-soluble ones such as hydrogen peroxide, peracetic acid, and sodium nitrite are particularly desirable. When oxidizing the pulp, add 0.1 to 8% oxide based on the weight of the pulp to the pulp slurry, and heat at 40 to 80°C for 10 to 180 minutes, preferably 30 to 120 minutes.
This can be carried out by reacting for minutes. When performing oxidation treatment by applying an oxidizing agent to paper, dilute the oxidizing agent to the required concentration in advance and apply 1 to 20 g/m ² (calculated as 100%) using a size press or similar equipment. do. Thus, the paper according to the present invention, or the containers, boxes, etc. made from it, have a sulfur content of 0.02 μg/g paper or less in the gas analysis, and have better protection than conventional metal packaging materials. rust effect,
Particularly, a rust prevention effect can be expected in non-contact parts. Therefore, transportation and storage of metals becomes easy, and the quality of metals as packaged products can be maintained. Hereinafter, the present invention will be explained in more detail using non-limiting examples. Example 1 and Comparative Example 1 Kraft cooking liquor containing 18% active alkali and 25% sulfidity was added to 600 g of softwood chips, and the mixture was cooked at 170° C. for 2 hours to obtain pulp with a cut par number of 50.
This pulp is beaten to 500ml of freeness, rosin size 0.3%, polyacrylamide 0.5%, aluminum sulfate 2.5% (all based on pulp weight)
was added to prepare a handmade sheet of 80 g/m ² .
The pH was 5.0. The thus prepared paper was heat treated under the following conditions and used as a sample for the rusting test. Temperature: 80°C Humidity: Absolutely dry Time: 2 days (Comparative Example 1), 5 days (Example 1) Example 2 Paper making, especially rosin size, polyacrylamide,
A sample for a rusting test was obtained by processing in exactly the same manner as in Example 1, except that aluminum sulfate was not used, and 0.3% of alkyl ketene dimer and 0.6% of cationic starch were used. The pH of the handmade sheet was 6.8. Example 3 A 30% hydrogen peroxide aqueous solution was applied at 20 g/m ² to a handmade sheet prepared in the same manner as in Example 1, and dried to prepare a sample for a rust test. Example 4 Coniferous wood chips were heated to 110 to 125° C. with a preheater, pressurized, and disintegrated with a finer. The obtained pulp was beaten to a freeness of 100 ml, and 0.2% of petroleum resin cation size was added to it, and the pH was 7.2 and the volume was 125 m2.
A handmade sheet of g/m ² was made and used as a sample for the rusting test. Comparative Example 2 A sample for rusting test was obtained in the same manner as in Example 1 except that no heat treatment was performed. Comparative Example 3 Using the pulp obtained in Example 1, hand paper was made according to the neutral paper making method of Example 2 to prepare a sample for rust development test. Rust development test (a) Gas generation conditions 100-200 g of pulp or paper (air-dried) was shredded and filled into a glass round bottom flask with a capacity of 1. This was sealed with a silicone rubber stopper and degassed using a vacuum pump. Next, the flask was placed in a constant temperature bath kept at 80°C and heated for 60 minutes. After cooling, the pressure inside the flask was returned to normal pressure using nitrogen gas, and the gas thus obtained was used as a sample for analysis. (b) Analysis conditions The gas chromatograph is a flame photometric detector (FPD; uses a 394 mμ filter for sulfur).
A device equipped with the following was used. The separation tube (column) is a glass tube with an inner diameter of 3 mm and a length of 4 m.
The inner surface was washed with 10N phosphoric acid, water and dried before use. The packing for the separation tube was a brown diatomaceous earth carrier (80/100 mesh) which was acid washed, treated with dimethyldichlorosilane, and coated with 25% triscyanoethoxypropane. The temperature of the sample introduction part was set to about 130°C, and the temperature of the separation tube was set to 100°C. Nitrogen gas is used as the carrier gas, and its flow rate is 35 (±5).
ml/min. (c) Analysis method Among the sulfur-containing gas components detected under the above analysis conditions, the retention time ratio (ratio to the retention time of methyl mercaptan) when methyl mercaptan is used as an internal standard is approximately 0.49 (0.46 to 0.51). A certain gas component was defined as a rust-generating gas component, and this was quantified from the area or peak height using a hydrogen sulfide calibration curve, and the value converted to sulfur content was calculated.
This value was defined as the amount of rust-generating gas components released per gram of paper (Sμg/g paper). (b) Rust development test (contact area) An SPCC iron plate was cut into 5 cm x 5 cm pieces, which were used as test pieces. Both sides of the test piece were sandwiched between the samples obtained in the above Examples and Comparative Examples and left for 10 days at 35°C and 90% RH, and the ratio of generated rust to the total contact surface area was expressed as a percentage. (e) Rust development test (contacted parts) A box with a side of 6 cm was formed using the paper obtained in the above corner examples and comparative examples in a sealable container where the temperature and humidity could be adjusted, and the inside of the box was polished and cold-rolled. Place the steel plate in the box, store it in the container adjusted to 35℃ and RH90%, leave it for 10 days, and measure the amount of rust (percentage of the total non-contact area) on the non-contact areas (sides and top surface). It was measured. (f) Silver rusting test 10g of each of the samples prepared in Examples 1 to 4 and Comparative Examples 1 to 3 was shredded, filled in a 50ml basis weight bottle with 5 to 10 silver-plated terminals, and sealed. .
This was heated at 140° C. for 2 hours, and discoloration of the silver terminal was visually determined. 【table】

Claims (1)

[Claims] 1. Gas generated by heating paper, paperboard, or cardboard used as packaging materials for metals at 80°C for 60 minutes under a pressure of 10 mmHg or less is detected using a gas chromatograph equipped with a flame intensity detector. Methyl mercaptan or methyl sulfide was used as an internal standard for retention time in the gas when analyzed at a separation tube temperature of 100°C using brown diatomaceous earth coated with triscyanoethoxypropane as the separation tube filling. 0.60 to 0.65 for the retention time of
Or, the components detected as showing 0.46 to 0.51 have a sulfur content of 0.02 μg/g paper or less,
The paper, paperboard, or corrugated board is characterized by suppressing rusting of metals.