JPH03227497A - Production of non-water-absorptive antirust paper - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing a non-water-absorbing anti-corrosion paper for packaging metal materials.

[Conventional technology]

Kraft paper impregnated with a rust preventive agent is generally used as packaging paper for metal materials.

The kraft paper used as the base paper is usually a kraft paper of no size or a weak size (Steckigt sizing degree is about 7 seconds at most) to help impregnate the rust preventive agent.

However, since the base paper of the above-mentioned anti-rust paper is kraft paper with no size or a weak size, it has high water absorption, and even after wrapping metal materials, it absorbs condensation water on the exterior surface and often causes damage to metal materials. There is a problem in that it causes rust. For this reason, preventing water absorption is an important issue for rustproof paper. As a solution to this problem, methods such as pasting a plastic film on one side of the anti-rust paper or applying paraffin wax or the like to make it waterproof have been adopted.

However, the above-mentioned waterproofing does not change the water absorbency of the base paper itself, but the edges of the rust-proof paper (
These methods were not always satisfactory, as water absorption from the cut end or damaged portion of the waterproof surface cannot be avoided, and rust occurs due to these causes as well.

[Problem to be solved by the invention]

An object of the present invention is to provide a rust-proofing paper in which the base paper itself is non-water-absorbing.

[Means to solve the problem]

The present invention is a method for producing non-water-absorbing rust-proof paper, which comprises applying an aqueous solution of a rust preventive agent to kraft paper having a Steckigt sizing degree of 20 seconds to 200 seconds.

[Effect]

In the present invention, the fact that the base paper itself is non-water-absorbing means that the kraft paper used as the base paper has a Steckigt sizing degree of 20 seconds to 200 seconds.

The appropriate sizing degree in the range of 20 seconds to 200 seconds varies depending on the basis weight, but when the basis weight is 20 to 30 g/+++'', it is 20 to 60 seconds (preferably 20 to 30 seconds);
~60 g/+'' (7), the time is 20 to 120 seconds (preferably 40 to 60 seconds), and when the basis weight is 80 to 100 g/Ilz, the time is 30 to 200 seconds (preferably 60 to 100 seconds).

Incidentally, when the Steckigt sizing degree is 20 seconds or less, water absorption occurs and is not sufficient from the viewpoint of non-water absorption, and on the other hand, when it is 20 seconds or more, it is not necessary from the viewpoint of non-water absorption.

Therefore, in order to bring the Steckigt sizing degree of kraft paper into the above range, it is necessary to adjust the amount of the sizing agent added at the pulp preparation stage before paper making.

The amount of sizing agent varies depending on the type of sizing agent used.

In addition, when adding a sizing agent, in addition to the sizing agent,
If necessary, a paper strength enhancer or the like may be added as a preparation chemical.

Paper making may be carried out using an acidic paper making method in which rosin and aluminum sulfate are added to the pulp slurry, but the acidic paper produced is susceptible to sulfuric acid radicals when the amount of rust preventive agent is reduced. , it is preferable to adopt a neutral papermaking method in which the pH is adjusted to 6 to 8, since this may also be a factor in the generation of rust.

In paper stock preparation in neutral papermaking, paper strength enhancers and sizing agents that have self-fixing properties are used.

As the paper strength agent, Mannich or Hoffman modified polyacrylamide, polyamide polyamine, cationically modified starch, etc. are used.

As the sizing agent, alkyl ketene dimer alkenyl succinic anhydride, rosin higher fatty acid polyamine, petroleum resin maleide polyamine, etc. are used.

The manufactured kraft paper has a high degree of size, but in order to provide higher waterproofness and prevent rust preventive from scattering to the outside, one side of the paper may be laminated with polyethylene, if necessary. It goes without saying that paraffin wax processing or addition of other reinforcing agents is preferred.

The rust preventive agents applied to and impregnated into the base paper thus obtained include dicyclohexylammonium nitrite,
Sodium benzoate, p-tert-butyl, sodium benzoate, sodium nitrite, carboxylic acid salts of various amines and sodium nitrite, benzotriazole and its derivatives, etc., which can be used alone or as a mixture of two or more of these. I can do it.

Among the rust inhibitors, sodium p-tert-butylbenzoate;
Or various amine salts of P-tert-butylbenzoic acid,
Various amine salts of fatty acids, methyl-IH-benzotriazole, which is a derivative of benzotriazole, etc. themselves,
It has a strong permeability into the base paper, and can be easily applied to and impregnated into strong-sized kraft paper, either alone or in combination.

When using other rust preventives, they have the disadvantage of having weak permeability into the base paper and not being able to penetrate sufficiently, so it is preferable to include a penetration enhancer in the aqueous solution of the rust preventive. Incidentally, isopropyl alcohol or isobutyl alcohol is preferred as the penetration enhancer.

In addition, in cases where the rust preventive agent itself has excellent permeability into the base paper, or because the rust preventive agent itself has poor permeability into the base paper, a permeation enhancer ( If a substance that remains on the paper after drying is contained, the non-water absorbing property of the anticorrosive paper after drying will be reduced. Therefore,
In such a case, it is desirable to further add a water repellent to the aqueous solution of the rust preventive agent so that it becomes non-water absorbent after being impregnated with the rust preventive agent and dried.

Effective water repellents include alkyl ketene dimer, alkenyl succinic anhydride, rosin higher fatty acid polyamine, petroleum resin maleide polyamine, silicone resin, and fluorine resin. As mentioned above, these are separately known as sizing agents, but here they are used in combination with the aqueous solution of the rust preventive agent as a water repellent imparting agent.

The prepared rust preventive agent is applied to and impregnated into strong-sized kraft paper in this state or in a state in which a thickening agent such as starch, CMC, or polyvinyl alcohol is added and blended.

The amount of the rust preventive to be applied is usually adjusted within a range of about 2 to 20 g/rr, more preferably about 5 to 15 g/rr. Incidentally, if it is less than 2 g/s", the rust prevention effect is poor, and if it is more than 20 g/s", it is in a supersaturated state and is not necessary.

The rust-proof paper thus obtained is a rust-proof paper with excellent non-water absorption and rust-preventing effects.

Examples of the present invention will be described below. However, it goes without saying that the present invention is not limited to these examples.
Part and Ano mean parts by weight.

Example 1 60g/n? Then, an aqueous solution of isopropyl alcohol of sodium benzoate was applied to unbleached neutral kraft paper with a Steckigt sizing degree of 50 seconds at a concentration of 10 g/rrr (dry weight) and dried to obtain rust-proof paper.

The anti-water absorption and anti-rust effects of this anti-rust paper were as shown in the attached table.

Example 2 60g/n? Sodium benzoate 76 parts p-tert-butyl sodium benzoate 20 parts polyvinyl alcohol
2 parts fluororesin 2 parts Naro aqueous solution coating amount (dry weight) is 10g/rrr
Rust-proof paper was obtained by coating and drying.

The anti-water absorption and anti-rust effects of this anti-rust paper were as shown in the attached table.

Example 3 Isopropylene alcohol consisting of 50 parts of amine salt of benzoic acid, 25 parts of hexamethylenetetramine, and 25 parts of sodium nitrite was applied to unbleached neutral kraft paper having a weightage of 60 g/rd and a Steckigt sizing degree of 50 seconds. An aqueous solution was applied and dried to give a coating amount (dry weight) of 10 g/- to obtain anticorrosion paper.

The anti-water absorption and anti-rust effects of this anti-rust paper were as shown in the attached table.

Example 4 An aqueous rust preventive alcohol solution having the same composition as in Example 1 was applied to unbleached neutral kraft paper with a weight per square meter of 100 g/nr and a Steckigt sizing degree of 80 seconds (dry weight) of 1.
It was coated and dried to obtain a rust-proof paper at a concentration of 3 g/at.

The anti-water absorption and anti-rust effects of this anti-rust paper were as shown in the attached table.

Comparative Example 1 An aqueous solution of sodium benzoate was applied to unbleached neutral kraft paper with a weight of 60 g/n (and a Steckigt sizing degree of 01 seconds) at a coating amount (dry weight) of 10 g/rII. It was dried to obtain rustproof paper.

The anti-water absorption and anti-rust effects of this anti-rust paper were as shown in the attached table.

Comparative Example 2 The weight is 60 g/rd and the Steckigt size is 5.
Sodium benzoate 78 parts p-tart-butyl sodium benzoate 20 parts Polyvinyl alcohol 2
The coating amount (dry weight) of Naro aqueous solution is 10 g/
The anticorrosive paper was obtained by coating and drying the coating to a coating temperature of nr.

The anti-water absorption and anti-rust effects of this anti-rust paper were as shown in the attached table.

Comparative Example 3 An aqueous Naro solution containing 50 parts of amine salt of benzoic acid, 25 parts of hexamethylenetetramine, and 25 parts of sodium nitrite was applied to unbleached neutral kraft paper with a weightage of 60 g/rrr and a Steckigt sizing degree of 01 seconds. Amount (dry weight) is 10g/rrr
Rust-proof paper was obtained by coating and drying.

The anti-water absorption and anti-rust effects of this anti-rust paper were as shown in the attached table.

[Non-Water Absorption] The water absorption and non-water absorption of the anti-rust papers obtained in the above Examples and Comparative Examples were measured, and the results were as shown in Table 1.

Table 1 (Note) @ Wood bark (JIS P-8141) Water absorption rate CJ, where the height of water uptake when the paper stock is suspended and the lower end is immersed in water is expressed as n, TAPPI 33-80) It is clear that the anti-corrosion paper obtained by the method of the present invention has an excellent non-water absorption effect, as shown in the display of the time (seconds) during which water droplets remain as water droplets when a certain amount of water droplets are dropped on the surface. be.

[Rust prevention effect]

In order to confirm the rust prevention ability of the rust prevention paper of the present invention, the following rust prevention test was conducted to evaluate the effect.

One side of the anticorrosive paper obtained in the examples and comparative examples was waterproofed with polyethylene laminate (thickness 20μ), and the cold-rolled steel plate had dimensions of 100cm x 150cm and a thickness of 1fi.Cleaning board 10
Two pieces of each paper stock were caramel-wrapped with the rust-proof paper side facing up, and the ends of the wraps were secured with craft adhesive tape to form test packages. Next, the packages are left on the wire mesh in the middle of the rust prevention test machine, one of the two packages was placed with the taped side facing down, and one of the other packages is placed on the bottom tier of stainless steel. The sample was left on a board with the taped side facing down, and the rust prevention test conditions of 5° C., 95% RH, 16 hrs and 50° C., 95% RH, 8 hrs were repeated for 1 month. (During this time, the presence of condensed water on the lower stainless steel plate was observed.) After the rust prevention test was completed, the package was opened and the occurrence of rust on the surface of the cold rolled steel plate was evaluated. The results were as shown in Table 2.

Table 2 [Effects] The present invention uses kraft paper with a Steckigt sizing degree of 20 seconds to 200 seconds as the base paper, and coats and impregnates it with an aqueous solution of a rust preventive agent. A highly effective rust-proof paper can be obtained.

Claims (4)

[Claims] (1) A method for producing non-water-absorbing anti-rust paper, which comprises applying and impregnating kraft paper with a Steckigt sizing degree of 20 seconds to 200 seconds with an aqueous solution of a rust preventive agent. (2) The method for producing non-water-absorbing rust-proof paper according to claim (1), characterized in that a penetration enhancer is contained in the aqueous solution of the rust-preventive agent. (3) The method for producing a non-water-absorbing rustproof paper according to claim (1), wherein the penetration enhancer is isopropyl alcohol or isobutyl alcohol. (4) The method for producing non-water-absorbing rust-proof paper according to any of claims (1) to (3), characterized in that a water repellent is blended into the aqueous solution of the rust-preventive agent.