JPS6055073A - Method for treating surface of metallic material - Google Patents

Abstract

PURPOSE:To improve adhesiveness and adhesion to thermoplastic resins, by treating the surface of a high-temperature metallic material in a vapor phase with a hydroxymethyl-substd. phenol. CONSTITUTION:A hydroxymethyl-substd. phenol (pref. one having an MW of 124-320) of formula I (wherein R is H, alkyl, phenyl, hydroxyl; n, m are each 1-3, n+m<=5) or II (wherein R2 is a direct bond or a vibalent group; n', m' are each 0-2, n'+m'>=1; rings A and B may be substituted with alkyl groups) is u used. The hydroxymethyl-substd. phenol is placed in a high-temperature atmosphere. A high-temperature (150 deg.C or above) metallic material is sprayed into the atmosphere filled with the vapor of the phenol to form a film of 1-100Angstrom in thickness on the surface thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the discovery of adhesive molecules capable of strongly bonding to metal surfaces [2], and relates to a technique for applying the adhesive molecules to metal surfaces. The present invention provides a method for forming an extremely thin coating layer on the order of angstroms on a metal surface.

It has been found that when a thermoplastic resin layer is coated on a metal surface treated with this adhesive molecule, it shows a revolutionary improvement not only in initial adhesiveness but also in adhesiveness over time, compared to conventional methods. The same effect was obtained even when coatings containing not only thermoplastic resins but also thermosetting resins were applied to metal surfaces treated with these adhesive molecules and dried. In the case of metal-to-metal bonding, etc., it is possible to maintain strong adhesion at the bonded portion.

In general, there is a strong desire in various fields to form a strong thermal adhesive bond between a metal and a thermoplastic resin layer.

For example, in the field of iron making, it is widely practiced to form a can body by overlapping both end edges of a metal material for forming a can body with a thermoplastic adhesive such as polyamide and thermally bonding. When joining metal materials together using a thermoplastic adhesive, the adhesive strength between the metal material surface and the thermoplastic adhesive is not necessarily high even at the initial stage.
In particular, there is a tendency for adhesion to deteriorate significantly over time. To solve this problem, an adhesive primer such as epoxy-phenolic resin is applied to the metal material, and after baking fc,
A method of thermally adhering with a thermoplastic resin adhesive through one layer of adhesive primer is generally employed.

L7 or L'4-, epoxy-phenolic paint is
In addition to being relatively expensive, it is also a cumbersome process in that it must be applied in the form of a coating on a metal material. Furthermore, since the above-mentioned paint must be applied in the form of an organic solvent solution, solvent costs and energy costs for baking are required, and the release of organic solvents into the atmosphere is not allowed, so in order to prevent this, after-sales care is required. Pollution control facilities such as burners will be required.

Such strong adhesion between thermoplastic resin and metal materials is strongly desired in applications such as film laminated steel sheets that replace conventional coated steel sheets, and in this case, the above-mentioned drawbacks are also the same. will occur.

Therefore, an object of the present invention is to provide a metal material that can improve the adhesion or adhesion between the metal material and a thermoplastic resin layer by applying extremely simple operations to the surface of the metal material. Another object of the present invention is to provide a surface treatment method for a metal material that can significantly improve the tendency of adhesive deterioration over time compared to when a conventional adhesive primer is applied to the surface of a metal material. It is in providing the law.

Still another object of the present invention is to provide a treatment method that can improve the thermal adhesion of a thermoplastic resin layer to a metal material by forming a treatment layer that is extremely thin compared to conventional adhesive primers and with extremely simple operations. According to the present invention, there is provided a method for surface treatment of a metal material, which comprises causing a hydroxymethyl-substituted phenol to act in a gas phase on the surface of the metal material maintained at a high temperature.

The invention will be explained in detail below.

The hydroxymethyl-substituted phenols used in the present invention are:
It has a chemical structural feature of having both a phenolic hydroxyl group and a hydroxymethyl group on the nuclear carbon atom.

=6- However, when this hydroxymethyl-substituted phenol is applied in the form of steam to the surface of a hot metal material, a remarkable improvement is brought about in the adhesive strength with the resin layer, especially in the adhesive strength over time. Generally, the tendency of the joint between the thermoplastic resin layer and the metal material to deteriorate over time can be evaluated by immersing the laminate in a dilute aqueous solution of citric acid at high temperature. For example, a known epoxy-phenolic resin primer is applied to an electrolytic chromic acid-treated steel plate (Tingai Free Fist Steel),
The can body joint is thermally bonded with nylon adhesive tape.
Even if the initial adhesive strength is about 6 to 7 K x 15 mm width, in the above-mentioned aging adhesion deterioration acceleration test,
After 96 hours of soaking, the adhesive strength is 1.1 to 1.5 K.
It is recognized that the width is on the order of 9/5 m.

On the other hand, according to the present invention, the can-body joint was formed by treating the heated TFS plate surface with saligenin (O-oxybenzyl alcohol) vapor and then similarly bonding the can body joint with a nylon adhesive. Not only does it show similar bond strength, but also 4.4-4.5 Kf/5 l even after 96 hours of citric acid solution immersion! It has become clear that the adhesive strength of 11 widths is maintained and that surface treatment with hydroxymethyl-substituted phenols brings about a significant improvement in the tendency of adhesive deterioration over time.

It is also extremely important for the surface treatment agent used in the present invention to have both a nuclear-substituted hydroxymethyl group and a phenolic hydroxyl group in terms of initial adhesive strength and adhesive strength over time. For example, when a metal surface is treated with the vapor of a compound having only phenolic hydroxyl groups, such as para-cresol or carbolic acid, it has been observed that the initial adhesive strength of the resulting adhesive structure is quite low; Only by using a surface treatment agent having a hydroxymethyl group in addition to a phenolic hydroxyl group can a high initial adhesive strength and a high adhesive strength retention rate over time be obtained.

Generally, when considering the deterioration of adhesion over time between a metal surface and its coating layer, it is necessary to consider not only the adhesiveness factor of the joint but also the water resistance factor. It is unclear exactly why the surface treatment of the present invention provides a combination of high initial bond strength and resistance to adhesive deterioration over time; It is thought that this may lead to improvements in these properties.

The surface treatment agent used in the present invention has at least one phenolic hydroxyl group and at least one hydroxymethyl group, and any compound can be used as long as it can generate steam at high temperatures. . Suitable examples of this surface treatment agent include, but are not limited to, the following:

In the general formula, R is a hydrogen atom, an alkyl group, a hydroxyl group, or a phenyl group, n is an integer of 1 to 6, m is an integer of 1 to 3, and 9-n-1-m Hydroxymethyl-substituted phenols, the total of which does not exceed 5.

In the above formula, hydroxymethyl is preferably bonded to the ortho position or the rose position with respect to the phenolic hydroxyl group. For example saligenin, O-hydroxymethyl-p-
Cresol, P-hydroxymethyl-〇-cresol,
O-hydroxymethyl-p-t-7'tylphenol,
O-hydroxymethyl-P-phenylphenol, di(
Mono- or dimethylolated products of O-hydroxymethyl)-p-cresol, 2,4-dihydroxymethyl-〇-cresol, 2,4-dimethyl-6-hydroxymethylphenol, resorcinol, catechol or hydroquinone.

General formula %Formula % (2) In the formula, R represents a direct bond or a divalent bridging group -1〇-, and each of L'' and m' is a !M number up to 2 including zero. , the sum of n'10m' is an integer greater than or equal to 1,
A hydroxymethyl-substituted trinuclear phenol represented by the following, wherein rings A and B may be substituted with an alkyl group. In the above formula (2), suitable examples of the bridging group R8 are a methylene group, a methyleneoxymethylene group (II, -0-
CD2-), ethylidene group, 2,2-pro group (-#//
-) etc.

In addition, hydroxymethyl derivatives of nanotols such as 2-hydroxymethyl-1-naphthol and 2,4-dihydroxymethyl-1-naphthol can also be used. 6
Of course, methylolated products of nuclear phenols can also be used for the purpose of the present invention, but as the number of benzene rings in the phenols used increases, the vapor pressure decreases and the amount of vapor generated becomes smaller compared to the same temperature. , it is desirable to use compounds up to dinuclear, especially mononuclear compounds.

Particularly suitable hydroxymethyl-substituted phenols for the purposes of the present invention are those having a molecular weight of 124 to 620, in particular 124 to 260, in particular one hydroxymethyl substituted in the ortho or para position to the phenolic hydroxyl group. A mononuclear or dimeric phenol having a group and another substituent at the remaining ortho or para position is preferred from the viewpoint of adhesion and surface treatment workability.

The metal material used for the surface treatment of the present invention may consist of any metal material in the form of a foil or plate.

For example, light metal plates such as steel plates, soft iron plates, stainless steel, aluminum plates, steel plates, and brass plates, or hot-dip plating of dissimilar metals such as tin, zinc, copper, chromium, nickel, and aluminum on the surface of these metal plates. or plated plates that have been electroplated, chemically treated plates obtained by chemically or cathodic electrolytically treating the surfaces of these metal plates with chromic acid, phosphoric acid, or a combination thereof, or anodized plates of the above metals, etc. can be mentioned. Of course, iron foil, steel foil,
Aluminum foil, copper foil, phosphoric acid and/or chromic acid treated metal foil, iron foil, steel foil plated with tin, zinc, copper, chromium, nickel, etc. can also be used in the treatment of the present invention.

In the present invention, it is also important to cause hydroxymethyl-substituted phenols to act in the gas phase on the surface of the metal material maintained at a high temperature in terms of initial adhesive strength and adhesive strength over time with the thermoplastic resin layer. For example, when hydroxymethyl-substituted phenols are applied to the surface of a metal material by means such as spray coating, the adhesion strength is only about half or less than that obtained with a scaffold when applied in the form of steam. Moreover, according to the present invention, by applying hydroxymethyl-substituted phenols to the surface of metal materials in the form of vapor, the coating film can be coated with an order of magnitude thinner than conventional coatings, that is, generally 1 to 1. 100
A significant advantage is that the adhesion enhancement effect can be obtained by applying only to a thickness of 1 to 60 angstroms (200 angstroms), especially 1 to 60 angstroms (200 angstroms). The thickness mentioned above is based on the electron spectroscopy for chemical analysis (Electron Spectroscopy for Chemical Analysis).
ron 5pectrozcopy For Chem
ical Analysis.

(hereinafter simply referred to as ESCA), by measuring the intensity of the 15 photoelectron spectra of carbon, which is a constituent element of the treated film on the treated metal surface, a relative comparison with a standard sample made by vapor-depositing carbon can be made. Then, X defined by the following formula
The film thickness was determined as follows. In addition, since there are organic substances attached to the metal material in advance, a blank test is performed and the thickness of the organic substance is subtracted, and the subtracted value is used as the processing thickness.
; Thickness of organic material layer I; Spectral intensity Ic of vapor-deposited carbon; Spectral intensity θ of sample; Emission angle of photoelectrons θ=90°, therefore, angle θ-114- λC; Average escape depth of photoelectrons λc=18. Maintaining the surface of the IJ metal material at a high temperature is also important in terms of adhesive strength; if this temperature is too low, the adhesive strength with the thermoplastic resin will become weaker than in the case of the present invention. It becomes markedly lower.

In the present invention, the surface of the metal material is 1507? or above, especially a temperature of 180 to 300C, most preferably 2
The treatment with hydroxymethyl-substituted phenols is preferably carried out at a temperature of 1 to 250C. When this temperature is lower than the above range, the degree of adhesion improvement is 1. compared to when it is within the above range. It will be low. The specific temperature conditions used vary depending on the type of hydroxymethyl-substituted phenol, and higher temperatures are preferably used for high molecular weight phenols.

Various means can be used to cause hydroxymethyl-substituted phenols to act on the surface of a metal material in a gas phase. In the simplest method, a hydroxymethyl-substituted phenol is placed in a hot atmosphere to generate a vapor of the compound, and a metal material is exposed to the vapor-filled atmosphere. Of course, hydroxymethyl-substituted phenols,
The compound can be used alone or in combination of two or more, and the compound may be supplied to the above-mentioned high-temperature atmosphere in the form of a lump, that is, without dilution, or as a solution, emulsion, or suspension in water or an organic solvent. It may be supplied in a diluted state such as a suspension. Furthermore, it may be supported on a carrier such as an inorganic pigment, a filler, various gel particles, glass beads, etc., and supplied to the atmosphere in a state in which the surface area is increased. In short, it should be understood that any shape and composition of hydroxymethyl-substituted phenols that can generate vapor can be used in the present invention.

For example, a paint solution applied to one side of a metal plate or metal foil contains hydroxymethyl-substituted phenols, and this single-sided coated metal plate is placed in a high temperature atmosphere in large numbers at small intervals. By placing them side by side,
It becomes possible to treat the surface of the metal material opposite to the coating surface with the vapor of hydroxymethyl-substituted phenols.

This process can be carried out either batchwise or continuously.

For example, a coiled or sheet-shaped metal foil or metal plate can be continuously fed into a tunnel-type heat treatment furnace and treated with steam, or a constant amount of metal material can be fed into the treatment furnace. Introduction 1. Processing can also be carried out by filling the processing furnace with steam after sealing the processing furnace.

In any of these cases, hot air containing vapor of hydroxymethyl-substituted phenols is prepared inside or outside the processing furnace, and this hot air is circulated within the processing furnace.
Steam treatment may also be used.

The time required for treatment in the gas phase with hydroxymethyl-substituted phenols varies depending on the concentration and temperature of the vapor in the gas phase, but it is sufficient as long as it is sufficient to form a coating layer with the thickness described above. Any time can be taken depending on the processing temperature and vapor concentration conditions. The thickness of this coating layer is extremely thin, and there is no particular advantage in forming a coating layer that is thicker than the above-mentioned range, so even if the treatment time is 10 minutes or longer. There is no particular advantage, and it is economically disadvantageous.

In the surface treatment method of the present invention, many thermoplastic resins, such as polyamides, polyesters,
It is particularly advantageously used for promoting adhesion or adhesion of acid-modified polyolefins, acrylic resins, vinyl resins, polycarbonates, etc.

Note that the surface of the metal material mentioned above is usually oiled with various oils such as dioctyl sebacate and cottonseed oil. The surface treatment of the present invention may be performed on a metal material provided with such an oil layer, or may be performed on a material from which the oil layer has been removed by degreasing treatment.

The invention is illustrated by the following example.

Example 1 Commercially available plate thickness 0゜1711DR-8, tin free steel (TFS), (Toyo Kohan (silk, itotsubu 0)
On top of this, phenol, p-cresol, bisphenol A1 salichenin, dimethylolated 4&l (-nuclear body) of P-cresol 18-, 1,11-dihydroIxy2,21-dihydroxy-4,4/-dimethyl - diphenylmethane (binuclear substance), purification reagents (each with a purity of 99% or more) were applied using the following method.

B. The reagent was dissolved in p-form, and a dry film of about 1 μm nm was spread on TFS and dried at 100° C. for 10 minutes.

It was applied in the same manner as in the previous section and dried at 200°C for 10 minutes.

C. TF supported in a metal container with a lid with a diameter of about 15 CI4 and a height of about 151 cm, with 1 g of reagent at the bottom, and at the same time supported using a glass holder so that they do not come into contact with each other.
After putting a small piece of S and putting the lid on, it was heated at 200°C for 10 minutes.

Then, the plates were bonded together using polyamide adhesive (80 μm thick nylon 12 film made by Toshi) and T
When the strength of the shape beer was measured, the results shown in Table 1 were obtained.

19-Example 2゜Using the Nine-7 Lee steel in Example 1, using the dimethylolated product of P-cresol (molecular weight: 168) in Example 1, and adjusting the heating temperature using the method (c) in Example 1. In addition, the adhesive strength was measured in the same manner as in Example 1 after each 10 minute vapor phase coating. Table 2 shows the results.

Example 6゜Similar to Example 2, however, the amount of dimethylol pre-added to the bottom of the metal container for vapor phase coating was increased or decreased, and the thickness of the coating was changed by repeating the application. The results are shown in Table 3, where the 21-adhesion strength was measured based on the strength of the beer.

Example 4. and Comparative Example 1: Same as Example 2, except that tin-free steel with a plate thickness of 0.20 was used and vapor phase coating was performed at 200'C. The film thickness was 12.24 mm.

On the other hand, an epoxyphenol paint with good adhesion (pending patent application, described in Japanese Patent Application No. 55-69012) was coated on the same tin-free steel so that the film thickness was 5 μm.
Baking was performed at 210°C for 10 minutes. Both were bonded in the same manner as in Example 1, and
The sample was held at ℃ and the change in adhesive strength was then measured.

Table 4 shows the changes in T-shaped beer strength.

22- Example 5. and Comparative Example 2゜ Commercially available aluminum plate (plate thickness 0.30w 5052 material)
A dimethylol compound of p-cresol was applied thereon in a vapor phase at 200 DEG C. using a vacuum cleaner. At this time, the coating film thickness is 1
It was 3.8,4'.

On the other hand, an epoxyphenol paint with good layer adhesion (patent pending, described in Japanese Patent Application No. 55-69012) was coated on the same aluminum plate to a film thickness of 5 μm, and heated at 210°C for 10 minutes.
Baking was performed for 1 minute.

The deterioration state of the adhesive force was examined for both in the same manner as in Example 4. The results are shown in Table 5.

Example 6. And Comparative Example 6゜New iron nickel plated steel plate (Canwell ■) Plate thickness 0
．． Saligenin was applied in a vapor phase at 200° C. for 10 minutes using the method (c) in Example 1 using a 24 m tube. The film thickness was 10.7 mm.

This sample was bonded in the same manner as in Example 1 and held at 90° C. in a 0.4 citric acid solution, after which changes in adhesive strength were measured.

On the other hand, a nickel-plated steel plate that was not coated with saligenin in a vapor phase was also bonded in the same way and its deterioration over time was examined. Table 6 shows the changes in the T-shaped beer strength.

Example Z and Comparative Example 4 A low carbon steel plate with a thickness of 0.22 sots coated with oil was used and degreased with trichlene. Thereafter, it was electrolytically degreased in 5% NaOH, then pickled in 1% H,S solution, and then washed with water. This was immersed in 6% chromic anhydride at 25° C. for 5 seconds, washed with water and dried to be used as a sample. This board was coated with vapor phase coating, adhesive, and
Deterioration over time was measured.

The results are shown in 47.

The coated film thickness was 297 mm.

25-Table 7 Example a and Comparative Example 5 Using the chromic acid immersion treated steel plate prepared in Example 7, the following experiment was conducted. First, saligenin was coated in a vapor phase at 200"C for 10 minutes using the method (c) in Example 1. The film thickness was 297mm.

This sample was sandwiched between maleic acid-modified polypropylene films (Liose 4M4 manufactured by Toyo Ink Manufacturing Co., Ltd., thickness: 40 μm), and the plates were thermocompression bonded together, and then the T-shaped beer strength was measured. Furthermore, the adhesive was held at 90° C. in a 0.4% citric acid solution, and the change in adhesive strength thereafter was measured.

26 On the other hand, a chromic acid immersion treated steel plate which was not coated with ligenin in a vapor phase was also bonded in the same manner and its deterioration over time was investigated. The results are shown in Table 8.

Patent applicant: Toyo Seikan Co., Ltd. . −gu 27- 570-

Claims (7)

[Claims] (1) A method for surface treatment of metal materials, which comprises applying hydroxymethyl-substituted phenols in the gas phase to the surface of the metal materials maintained at high temperatures. (2) The method according to claim 1, in which the surface of the metal material is maintained at a temperature of 1000° C. or more and the hydroxymethyl-substituted phenols are acted on. (3) The hydroxymethyl substituted phenol is 124
The method according to claim 1, wherein the molecular weight is from 3,200 to 3,200. (4) In the general formula of the hydroxymethyl-substituted phenols, R is a hydrogen atom, an alkyl group, a hydroxyl group, or a phenyl group, n is an integer of 1 to 3, and m is an integer of 1 to 3; , the sum of n+m shall not exceed 5. The method described in Section 1. (5) The hydroxymethyl-substituted phenols have the general formula % formula % (2) where R1 is a direct bond and tfC is a divalent bridging group,
Each of n' and m' is an integer up to 2 including zero,
Claim 1: A hydroxymethyl-substituted trinuclear phenol represented by the following, wherein the sum of n'10m' is an integer of 1 or more, and rings A and B may be substituted with an alkyl group. Method described. (6) Special feature 1FFi1' in which the treatment with the hydroxymethyl-substituted phenol is carried out so that the thickness of the treated coating layer formed is 1 to 100 angstroms! !
The method described in item 1 of the scope of the request. (7) The method according to claim 1, wherein the metal material is introduced into a heat treatment furnace and the metal material is treated by exposing it to a high temperature atmosphere containing vapor of hydroxymethyl-substituted phenols.