JPH044146A - Fluorine resin film-coated a1 alloy plated steel plate - Google Patents

Abstract

PURPOSE:To improve adhesion, friction resistance, simplicity of processing and material strength by forming the thermally fusible coat of thermoplastic fluorine resin film on the surface of an A1 alloy-plated steel plate containing a specific amount of Si with an aqueous silane compound solution treated layer as a background. CONSTITUTION:A silane compound is allowed to adhere uniformly to the surface of an A1 alloy-plated steel plate by soaking the plate in an aqueous silane compound solution and then, after moisture is allowed to completely evaporate, a thermoplastic fluorine resin film is thermally fused to the surface of the compound to form a film. The thermal fusion method is to first heat the plate with a pretreated layer of silane compound at higher than the melting point of thermoplastic film resin, and after that, a thermoplastic fluorine resin film is pressed on an area where a silane compound-treated layer is formed using a roll. Subsequentially, a layer of thermally fused fluorine resin film is formed. The A1 alloy plated on the steel plate should contain 1 to 15 wt.% of Si. Further, the silane compound used is beta(3,4 epoxycyclohexyl) ethyltrimethoxy silane.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a Si-containing Al alloy plated steel sheet to which a fluororesin film is heat-sealed.

In particular, this Al alloy-plated steel sheet with a fluororesin film layer has not only high rigidity but also excellent film adhesion, wear resistance, and processability, so it is used for baking bread, cakes, confectionery, etc. It is suitably used as a material for food cooking and processing utensils such as baking molds and flat plates, especially heating cooking utensils.

Moreover, the present invention is not limited to the above-mentioned applications, but also has heat resistance,
Because it has excellent electrical properties and chemical resistance, it can also be used as a material for electronic parts, printed circuit boards, special cleaning container materials, microwave oven inner panels, rice cooker inner pots, and kitchen utensil materials. It is widely available.

[Prior art] Conventional heating cooking utensils, such as baking molds for baking bread, cakes, and confectionery, are often coated with silicone resin on the inside to prevent sticking and release properties. It is being However, such materials coated with silicone resin have poor abrasion resistance, so the coating often disappears within a few months, and as a result, scorching occurs early. Furthermore, although this silicone resin coating material has good mold releasability, the reality is that it is actually necessary to apply oil in combination. However, using oil produces soot, which often sticks to bread, cakes, and sweets. Of course, products with soot adhering to them have a lower commercial value and are also unfavorable in terms of food hygiene. As a result, manufacturers of bread, cake, and confectionery have had the problem of having to frequently clean their heating equipment.

Against this background, much research and development has been carried out on the above-mentioned materials for baking molds that do not stick even without the use of oil and have excellent mold release properties. However, the reality is that most of them have poor corrosion resistance and poor adhesion, so they have not been put into practical use. Below, some conventional techniques developed to meet such demands will be described.

(1) JP-A-61-137534, JP-A-6
Publication No. 1138567: These technologies relate to materials in which stainless steel or plated steel sheets are coated with tetrafluoroethylene resin, and although the mold release properties are good, there are pinholes in the coating, and the coating is not as smooth as a film. The problem is that it is difficult to obtain sex.

(2) Special Publication No. 59-16836, Special Publication No. 59-1
Publication No. 6837: These techniques relate to a material in which an Al-plated steel plate is coated with a fluororesin. That is,
This is a technique in which a plated steel plate is annealed at 150 to 600°C, the surface is then mechanically roughened by sandblasting, liquid honing, etc., and the roughened surface is coated with a fluororesin. The reality is that these technologies also have the same problems as mentioned above, and there is still room for improvement.

(3) Special Publication No. 54-24434, Special Publication No. 59-1
No. 0304, JP-A-63-126728: The techniques described in these publications are known as fluororesin film laminate materials.

First, what is described in Japanese Patent Publication No. 54-24434 is
This relates to an Al material made by subjecting Al or an Al alloy to direct current electrolytic etching in an aqueous chloride solution, then first coating the surface with a fluororesin dispersion, and then hot-pressing a thermoplastic fluororesin film onto the surface. be. This technology has good film adhesion, but because it uses electrolytic etching, it takes time and requires expensive equipment.In addition, it has poor productivity and requires boiling water testing (boiling water testing). There is a problem with film adhesion (# type Erichsen test result) after being immersed in for 10 hours.

Next, in the method described in Japanese Patent Publication No. 10304, an Al or Al alloy plate with a surface roughness of 2 μm or less is coated with 3
This invention relates to an alloy plate formed by forming an anodic oxide film of μm in thickness and further bonding a thermoplastic fluororesin film to the surface by thermocompression. Since this technology is applied to electrical parts that utilize the dielectric constant of a thin film of fluororesin film, the adhesion of the film is not much of an issue. It can be said that it is unsuitable for use.

The material described in JP-A-63-126728 is an Al material formed by forming a hydrated oxide film on a 81 or Al alloy plate and then covering it with a thermoplastic fluororesin film, and a hydrated oxide film. This relates to an old material in which the thermoplastic fluororesin and the tetrafluoroethylene resin film are thermally fused together after the film is formed and then treated with an aminosilane compound. This technology relies only on chemical adhesion for film adhesion and lacks physical adhesion, resulting in low adhesion, and peeling of the film was observed in boiling water tests.

[Problem to be solved by the invention]

As explained above, each conventional technology has been used to make bread, cakes,
This is a necessary condition as a material for cooking utensils for sweets, etc.
The reality is that the film's adhesion, abrasion resistance, processability, and strength of the material are insufficient, and as a result, it has not been put to practical use.

Therefore, the purpose of the present invention is to develop a material that is not only highly productive but also has excellent properties such as film adhesion, abrasion resistance, processability, and material strength (rigidity). Al is suitable for use as a material for processed cooking utensils, electronic equipment, etc., with excellent mold releasability.
The purpose is to provide alloy plated steel sheets.

[Means for Solving the Problems] In order to achieve the above-mentioned objectives, the present inventors sought to find the necessary conditions for baking mold materials for bread, cakes, confectionery, etc., by improving strength, corrosion resistance, and heat resistance. We considered gender, etc. As a result, it was discovered that Si-containing Al alloy plated steel sheet was the most suitable basic material.

On the other hand, as a film to be applied to the surface of the above-mentioned Al alloy plated steel sheet, fluororesin emulsion paint coating was considered, but it was found to be inferior in corrosion resistance and abrasion resistance. The present invention was conceived based on the finding that the properties of the film are significantly improved when the following pretreatment film is synthesized based on the film.

That is, the first aspect of the present invention is to apply a heat-sealable film of a thermoplastic fluororesin film to the surface of an old alloy plated plate containing 1 to 15% by weight of Si, which has a treated layer of an aqueous silane compound solution as a base. The second one proposed in the present invention is a fluororesin film-coated Al alloy plated steel sheet formed by forming a fluororesin film-coated Al alloy plated steel sheet. This is a fluororesin film-coated Al alloy plated steel sheet formed by forming a heat-sealing film of a thermoplastic fluororesin film on the surface of a -A I alloy plated copper sheet.

The third method proposed by the present invention is to remove Si by 1% before treatment with an aqueous solution of a silane compound or coating treatment with a thermoplastic fluororesin dispersion containing a silane compound.
After roughening the surface of an Al alloy-plated steel sheet containing ~15% by weight, or directly forming a hydrated oxide film without roughening the surface, and then thermally bonding a thermoplastic fluororesin film to the outermost layer. This is an Al alloy plated steel sheet coated with a fluororesin film.

In the present invention, it is desirable that the old alloy-plated steel sheet be roughened as necessary.

Below, the structure of the old alloy-plated steel sheet of the present invention will be further explained in detail.

Now, materials for heating cooking utensils used as molds for baking bread, cakes, sweets, etc. are required to have a certain degree of rigidity to prevent deformation due to impacts during handling. By the way, conventional materials treated with fluororesin require easy surface treatments such as anodizing, electrolytic etching, etc. to roughen the surface and form a hydrated oxide film, so they are used instead of steel sheets. , Al or Al
Alloy plate was used. However, this Al or Al alloy plate has a drawback that it has low rigidity and is easily deformed during handling.For example, because of its low rigidity, it is easily deformed even during manufacturing, and of course, in this case, it loses its commercial value.

Therefore, in the present invention, we focused on a steel plate that itself has high rigidity, and used a steel plate that was coated with an Al alloy suitable for the above-mentioned surface treatment. However, in -C Al alloy plated steel sheets, Al
Alternatively, anodic oxidation, electrolytic etching, and hydrated oxide film treatment, which are pretreatments for applying fluororesin treatment to Al alloy plates, cannot be applied.

That is, the plating layer of an Al alloy plated steel sheet is usually 20
The thickness is only ~40 μm, and when electrolytically etched, the plating layer disappears immediately, making it impossible to sufficiently roughen the surface or form an oxide film. Furthermore, in anodic oxidation, the underlying iron surface has an adverse effect on the processing solution, accelerating the deterioration of the solution and making it difficult to form an oxide film. Therefore, it is not preferable to heat-seal a fluororesin film directly onto such an Al alloy plated steel plate.

Therefore, the present inventors studied pretreatment for effectively performing thermal fusion bonding between an Al alloy plated steel sheet and a thermoplastic fluororesin film. As a result, in order to perform such heat fusion effectively, it is first necessary to widen the bonding area, and in order to increase the bonding area, it is necessary to roughen the surface of the Al alloy plated steel plate by shot blasting etc. It turned out to be a good thing.

However, as the research progressed further, it was found that the above-mentioned surface roughening alone did not provide sufficient adhesion. For this reason, the present inventors investigated various pretreatments for increasing the adhesive strength of the heat-sealing film. As a result, it has been found that among many pretreatment substances, silane compounds are particularly effective for the application of the present invention. For example, β(3°4 epoxycyclohexyl)ethyltrimethoxysilane, T-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyljethoxysilane, N-β(aminoethyl)T-aminopropyltrimethoxysilane. , N-β(aminoethyl)T-aminopropylmethyldimethoxysilane, N-phenyl-T-aminopropyltrimethoxysilane, and other silane compounds have been found to be effective in pre-treating the steel sheet. It is.

In addition, in this pretreatment, a method for forming an extremely thin layer of silane compound at the interface between the Al alloy plated steel sheet and the film is to immerse the needle plate in an aqueous solution of one or more of the above silane compounds, and then Squeeze it with a linga roll,
It is preferable to uniformly adhere to the surface of the steel plate by applying with a roll coater, spray or brush, and then completely evaporate the water. After performing such pretreatment, a thermoplastic fluororesin film is heat-sealed over the pretreatment to form a film. The heat fusion method involves first heating a steel plate having a pre-treated layer of a silane compound to a temperature higher than the melting point of the thermoplastic fluororesin film, and then roll-pressing the thermoplastic fluororesin film onto the surface on which the silane compound treatment layer is formed. This is used as a heat-adhesive layer of the fluororesin film.

In this way, by forming a heat-sealing film of a thermoplastic fluororesin film with excellent adhesion on the surface of an Al alloy-plated steel sheet together with a silane compound treatment layer,
The intended purpose of the invention can be realized.

In addition, in the present invention, the Al alloy plated on the steel plate is
A material containing 1 to 15% by weight of Si is used.

When a silane compound layer is formed on the surface of a steel plate plated with an Al alloy having such a composition, the adhesion of the heat-sealing film of the thermoplastic fluororesin film is significantly improved. The reason may be as follows. That is, the Si contained in the Al alloy plating layer is oxidized to SiO□ etc. on the surface, and during thermal fusion, this Si oxide forms a strong bond with the 5i-OH group of the silane compound, while the film The adhesion of the film to the surface is actually significantly improved, probably because the silane undergoes some kind of reaction with the silane and becomes compatible.

The present invention, which was produced based on such knowledge, either applies an aqueous solution of a silane compound to the surface to be treated of a steel plate to directly form a silane compound base treatment layer, or a method containing 1 to 15% by weight of Si. On the surface of a steel plate with an Al alloy plating layer,
First, a thermoplastic fluororesin solution containing 0.5 to 10% by weight of 0.5 to 10% by weight is applied and heat-sealed to form a film-like heat-sealing layer of thermoplastic fluororesin. In forming this thermal adhesive layer, the silane compound added to the thermoplastic fluororesin dispersion is contained in an amount of 0.5 to 10% by weight based on the thermoplastic fluororesin content. That is, if the amount of the added silane compound is less than 0.5% by weight, the concentration of 5i-OH groups involved in bonding with the steel sheet surface is low, and no improvement in adhesive strength is observed. Also, this amount is 10
If the weight percentage is exceeded, the layer formed by applying the thermoplastic fluororesin dispersion becomes brittle, and the adhesion of the product to which the thermoplastic fluororesin film is later heat-sealed deteriorates significantly in the processed area. . Therefore, the amount of the silane compound added to the thermoplastic fluororesin dispersion is preferably 0.5 to 10% by weight.

In addition, the resin applied to the thermoplastic fluororesin dispersion is 4
Fluorinated ethylene-perfluoroalkoxyethylene copolymer resin (PFA), tetrafluorinated ethylene hexafluorinated propylene copolymer resin (FEP), and tetrafluorinated ethylene-ethylene co-M resin (E'r FE) are suitable. It is.

Next, the reason why it is preferable to include 1 to 15% by weight of Si in the Al alloy plating layer will be explained.

That is, when the Si content in the Al alloy is less than 1% by weight, the concentration of Si oxide on the surface of the alloy plating layer is low;
Therefore, the bonding ratio of the silane compound with the 5i-OH group also decreases, making it impossible to obtain sufficient adhesive strength. Furthermore, if the Si content exceeds 15% by weight, although the film has good adhesion, the component distribution of the plating layer becomes uneven.
Therefore, when a boiling water immersion test is performed, the plating layer corrodes from the end face, corrosion occurs on the coating film, and the film peels off.

From this, the Si concentration in the alloy plating layer is preferably 1 to 15% by weight.

The surface of the above-mentioned alloy-resistant plated steel sheet is preferably roughened. However, in this surface roughening, it is necessary to limit the maximum roughness (RMA) i) to 20 μm or less because the plating layer of the Al alloy plated steel sheet is as thin as 20 to 40 μm. If this maximum roughness (RMAX) exceeds 20 μm, the base of the plating layer will be exposed, leading to a decrease in corrosion resistance and film adhesive strength.

As described above, in the present invention, prior to forming a thermoplastic fluororesin film, it is effective to provide a pretreatment layer using a silane compound as a base treatment for improving the film properties.

However, research to further improve the film properties revealed that in addition to roughening the Al alloy plated steel sheet, it is effective to provide a hydrated oxide film as a base for the silane compound base treatment layer. I found out that it is.

The surface treatment for this hydrated oxide film involves immersing the Al alloy plated steel sheet in a boiling (>90°C) aqueous solution containing basic organic compounds containing 0.2 to 2% of amino compounds and ammonium compounds. This is done by

Examples of amino compounds and ammonium compounds include:
Triethanolamine, jetanolamine, monoethanolamine, ammonium acetate and the like are preferably used.

Note that the formation of a hydrated oxide film after the surface roughening treatment of the At alloy-plated steel sheet is carried out for a treatment time of 1 to 5 minutes in order to prevent deterioration of the treatment solution due to dissolution of Si in the treatment bath. It is preferable.

Next, the thermoplastic fluororesin films used in the present invention include tetrafluoroethylene-perfluoroalkoxyethylene copolymer resin (PFA) film, tetrafluoroethylene-67fluoropropylene copolymer resin (F E P ) film, 47-fluorinated ethylene ethylene copolymer resin (ETFE)
) film is preferably used. Although the thickness of this fluororesin film is not particularly limited, it is preferably 10 to 100 μm for use in baking molds for bread, cakes, confectionery, and the like.

[Examples and comparative examples]

Examples of the present invention will be described below along with comparative examples.

Examples 1 to 16 The surfaces of steel plates plated with Al alloys containing 5 wt%, 10 wt%, and 15 wt% of Si were degreased and cleaned with a weakly alkaline degreasing solution, and then treated with the silane compounds shown in Table 1. Then, a thermoplastic fluororesin film was laminated. The primary product obtained.

The adhesion strength and abrasion resistance of the secondary film were examined. The results are also shown in Table 1.

Comparative Examples 1 to 5 Al-plated steel sheets containing no Si, and each A containing 9 wt% and 20 wt% of Si.
A laminated steel plate was manufactured using a steel plate plated with L alloy as a material according to the specifications shown in Table 2. The obtained product was subjected to the same test as in the example. The results are also shown in Table 2.

Examples 17 to 32 A thermoplastic fluororesin dispersion containing a silane compound was applied to a steel plate plated with an 81 alloy containing 9 wt% Si, and a PFA film and F
A product was obtained by heat-sealing the EP film. Performance test results regarding primary and secondary adhesion and abrasion resistance of this product are also shown in Table 3.

Test items, test methods, and judgment methods ■Primary adhesion test of film Prepare a test piece according to JTS 6744 # Erichsen test method, extrude 5 mm using an Erichsen tester, and then cut the extruded part of the film with a knife. Grasp it with tweezers and forcibly peel off the film.

Evaluation criteria ○: The film cannot be floated.

△: The film is allowed to grow, but the film cannot be peeled off.

×: The film can be peeled off by letting it grow.

■Film secondary adhesion test # Prepare a test piece according to the Erichsen test method of JTS 6744, extrude it to 6 mm using an Erichsen tester, immerse the test piece in boiling water for 10 hours, wipe off the moisture, After a period of time has elapsed, the cut end of the film at the extruded portion is cut with a knife, and the film is forcibly peeled off by grasping it with tweezers.

Evaluation criteria ○: The film cannot be floated.

Δ: The film can be made to last, but 1, the film cannot be peeled off.

×: The film can be peeled off by letting it grow.

■Abrasion test A test piece of 150 x 150 mm square was fixed on a rotary table, and a Scotch Tawashiku Sumitomo 3M was fixed on the surface of the test piece.
A load of 2 kg was applied to a 70 x 120 mm (manufactured by Co., Ltd.), and the rotary table was rotated at a speed of 63 rpm. The Scotch scrubber is soaked with water. The judgment was based on the number of rotations until the film was removed by rubbing with a Scotch scrubber and the substrate was exposed.

■ Mold releasability test 27 drops of the model liquid of (b) m were added to the steel plates obtained by the methods of Examples 1 to 32 and Comparative Examples 1 to 5, and baked in an atmosphere of 230'C for 15 minutes. After that, cool it down.

After that, this is a test to confirm the pattern when the baked-on material separates from the steel plate. In this test, it was confirmed that all samples could be removed cleanly by rubbing with tissue paper. From this, it can be said that when a thermoplastic fluororesin film is used, the mold release properties of bread baking molds and the like are good.

Composition of model liquid; C soft flour: 20g, shortening: 1g.

Mix 10 g of sand tF and 5 ml of milk and knead. ] From the test results described above, ■ Al alloy plated steel sheet containing 5 to 15% Si,
After forming a silane compound treatment layer as a base treatment, heat-seal a thermoplastic fluororesin film, or
% of Al alloy plated steel sheet, as a surface treatment,
A thermoplastic fluororesin dispersion containing 0.5 to 10% of a silane compound is applied to form a film, and then a heat-adhesive film of a thermoplastic fluororesin film is provided on top of the film. It was confirmed that each of the above Al alloy-plated steel sheets became a film-laminated steel sheet with excellent film adhesion and wear resistance.

In addition, the surface of an Al alloy plated steel sheet containing 5 to 15% Si is roughened in advance or treated with a hydrated oxide film, and then a thermoplastic fluororesin film is heat-sealed. It was found that the synergistic effect of these and the silane compound resulted in superior -N coating properties.

〔Effect of the invention〕

As explained above, the film laminated Al alloy plated steel sheet according to the present invention has excellent adhesion, wear resistance, and mold releasability, and also has excellent rigidity, which is a characteristic of the Al alloy plated steel sheet material. Therefore, in addition to applications such as materials for cooking processing equipment, materials for kitchen equipment, and inner panels of microwave ovens, it can also be applied to fields such as materials for electronic components and printed circuit boards, providing inexpensive materials suitable for a wide range of uses. can do.

Claims (1)

[Claims] 1. S having a treated layer of an aqueous silane compound solution as a base
A fluororesin film-coated Al alloy plated steel plate, which is obtained by forming a heat-sealing film of a thermoplastic fluororesin film on the surface of an Al alloy plated steel plate containing 1 to 15% by weight. 2. Forming a heat-sealed film of a thermoplastic fluororesin film on the surface of an Al alloy plated steel sheet containing 1 to 15% by weight of Si, which has a treated layer of a thermoplastic fluororesin dispersion added with a silane compound as a base. A fluororesin film coated Al alloy plated steel sheet. 3. The fluororesin film-coated steel sheet according to claim 1 or 2, wherein the fluororesin film-coated Al alloy plated steel sheet is characterized in that a hydrated oxide film is provided below the base treatment layer using a solution containing a silane compound. .