JPH06328619A - Production of laminate - Google Patents

Abstract

PURPOSE:To obtain a laminate excellent in corrosion resistance, heat resistance, adhesiveness and bonding durability by improving the adhesion of a metal and a resin coating layer by stably forming a sintered primer layer having a large number of fine cracks suitable for developing anchor effect formed thereto. CONSTITUTION:In a method for producing a laminate 10 by successively providing an organotitanate sintered primer layer and a resin coating layer on the surface of a metal plate M, organotitanate is applied to the surface of the metal plate M by a coating device 3 while the metal plate M is continuously sent and the coated metal plate M is passed through a heating device 4 while steam is supplied to the heating device 4 from a steam supply device 5 and heated in the steam atmosphere to form a sintered primer layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a laminate of a metal and a synthetic resin, and more particularly to a method for producing a laminate excellent in corrosion resistance, heat resistance, adhesion between metal and synthetic resin and adhesion durability. .

[0002]

2. Description of the Related Art Conventionally, in order to impart corrosion resistance to metal,
A synthetic resin coating layer (hereinafter referred to as "resin coating layer"), which serves as a corrosion-resistant layer, is provided on the surface by a method such as a laminated body provided with an adhesive layer, or by directly fusing without using an adhesive. Known laminates are known. Such a laminate is widely used for applications such as roofing materials, outer wall materials, rain gutters, and resin-coated metal pipes.

In these laminates, the initial adhesive strength between the metal and the resin coating layer is generally strong, and almost good use results have been obtained for short-term use. However, during long-term use, the adhesive strength between the metal and the resin coating layer decreases due to absorption of water and chemicals from the surface of the resin coating layer, deterioration of the adhesive layer due to heat, etc. Repeated shear adiabatic stress due to a large difference in linear expansion coefficient and factor of release of residual strain at the time of molding the resin coating layer cause peeling at the adhesive interface and shrinkage of the resin coating layer. Occasionally, rust or corrosion could occur, leading to a major accident.

In order to solve such a problem, in Japanese Patent Laid-Open No. 3-281667, an organic titanate is applied to a metal surface, and this coating film is baked to form a sintered primer layer, and a sintered primer layer is formed thereon. Techniques for coating synthetic resins have been proposed. This technique utilizes the fact that the formed sintered primer layer has excellent adhesiveness with a metal and adhesiveness with a resin coating layer.

[0005]

DISCLOSURE OF INVENTION Problems to be Solved by the Invention As a result of research on the technique described in JP-A-3-281667, the present inventors found that the surface of a sintered primer layer formed by baking an organic titanate was It has been found that a large number of cracks are generated, the synthetic resin coated into such cracks increases the adhesive area, and the so-called anchor effect is exerted, so that high adhesiveness can be obtained. It was

Further, since it is considered that the shape of the cracks affects the adhesiveness and the adhesive durability, further research has revealed that when a large number of fine cracks are generated, the adhesiveness and the adhesive durability are improved. However, it was found that when the width of cracks is wide and the number of cracks is small, the adhesiveness and the adhesive durability are considerably inferior.

However, it has not been clarified under what kind of sintering conditions the crack having the preferable shape as described above is obtained, and therefore, a laminate having high performance and quality can be stably obtained. I couldn't.

The present invention has been made as a result of further research in view of the above problems of the prior art,
By eliminating the problems of the prior art and optimizing and keeping the conditions for forming a sintered primer layer of organic titanate excellent, it has excellent corrosion resistance, heat resistance, adhesion between metal and resin coating layer, and adhesion durability. The purpose is to obtain a laminate.

[0009]

In order to achieve the above object, the method of the present invention comprises applying a metal titanate to the surface of a metal and then heating the metal titanate to form a sintered primer layer of the organic titanate. In a method for producing a laminate in which a synthetic resin coating layer is formed on a layer, the gist is that a metal coated with organic titanate is heated in a steam atmosphere to form a sintered primer layer.

In the present invention, the metals include iron, steel, stainless steel, aluminum, copper, zinc and the like, which are generally called metals. Further, the shape of the metal is not limited to the plate shape, and may be a tube, a rod, or any other shape.

The metal surface is subjected to a blasting treatment, a degreasing treatment with an alkali or the like, a treatment for removing an oxide film such as rust with hydrochloric acid, a sulfuric acid, a nitric acid or the like in order to improve the adhesion to the sintered primer layer. It is preferable.

In the present invention, as the organic titanate, tetra-n-butoxy titanium, tetra-i-propoxy titanium, tetrakis (2-ethylhexyloxy) is used.
Titanium, di-i-propoxy bis (acetylacetonato) titanium, di-n-butoxy bis (triethanolaminato) titanium, propanedioxytitanium bis (ethylacetoacetate), propanedioxytitanium (acetylacetonato) (Ethyl acetoacetate) and the like.

As a method for applying these organic titanates to a metal surface, a usual applying means such as a roll, a brush or a coating rod can be used.

In the present invention, as a method of heating the metal coated with the organic titanate in a steam atmosphere, the metal is heated in a humidifier filled with steam or heated while spraying steam from a nozzle or the like. In the case of continuous production, there may be mentioned a method in which steam is supplied into a heating device having a closed structure so that the steam is passed while being heated and sintered. The atmosphere of water vapor has a relative humidity of 50 to 100%, preferably 70 to 95%.

Means for heating the applied organic titanate include known heating methods such as heating with a burner, blowing hot air, and using induction heating. The preferable heating temperature of the organic titanate coating film is 250 to 450.
C., more preferably 350 to 420.degree. 250 ° C
If less than 450, the temperature is too low and the sintering is not sufficiently performed.
If the temperature exceeds ℃, the sintered primer layer will be in a shattered powder form, and it will be difficult to obtain good adhesion between the metal surface and the sintered primer layer and good adhesion between the sintered primer layer and the resin coating layer.

The thickness of the sintered primer layer formed on the metal surface is preferably 0.1 to 20 μm, more preferably 0.
5 to 10 μm.

In the present invention, as the synthetic resin used for the resin coating layer, known synthetic resins can be used, but synthetic resins having particularly good adhesiveness to metals are preferable,
For example, thermoplastic resins such as silane-crosslinked polyethylene, carboxylic acid-modified polyethylene, polyvinyl acetate, polyvinyl acetal, polyvinyl alcohol, and polyamide, and thermosetting resins such as epoxy resin, phenol resin, urea resin, and polyisocyanate are suitable.

A filler may be added to the synthetic resin for the purpose of improving the cohesive strength, reducing the linear expansion coefficient of the resin coating layer, and suppressing shrinkage due to residual strain release during molding of the resin coating layer. . As the filler, short glass fibers, wollastonite, potassium titanate whiskers, talc, mica,
Examples thereof include silica, calcium carbonate, calcium sulfate, magnesium carbonate, magnesium hydroxide, magnesium oxide, kaolin clay, wax stone clay, carbon black, graphite, titanium oxide, and the like, or a mixture of two or more thereof.

These fillers are preferably surface-treated in order to improve their compatibility with the synthetic resin. Examples of the surface treatment agent include silane coupling agents, titanium coupling agents, zirconium coupling agents, aluminum coupling agents, zircoaluminate coupling agents and the like.

The synthetic resin may be added with an antioxidant, an ultraviolet absorber, a coloring agent or the like which does not impair the effects of the present invention.

As a method for forming the resin coating layer on the sintered primer layer formed on the metal surface, a synthetic resin molded body previously molded by extrusion molding, injection molding, calender molding, compression molding or the like is bonded with an adhesive. Adhesion method that adheres through, method of extrusion coating molten synthetic resin on metal surface, method of electrostatically adhering powdered synthetic resin by heating and melting, and adhesion, heating in fluidized bed of powdered synthetic resin Examples of the method include a method of immersing the above metal to melt and adhere the synthetic resin, a method of applying the synthetic resin in a liquid state or dissolved in a solvent and heating and curing the synthetic resin, and the like.

A continuous production system may be adopted in order to improve productivity. FIG. 1 shows an example of a manufacturing process of a laminated body by a continuous production method. As shown in FIG. 1, a metal plate M is continuously fed from the uncoiler 1,
After degreasing treatment with an alkaline solution in the surface treatment tank 2 and oxide film removal treatment with an acid, organic titanate is applied with a coating device 3, and then steam is supplied from a steam supply device 5 to a heating device 4 having a substantially sealed structure. While forming a sintered primer layer by passing through the heating device 4, the surface of the sintered primer layer is extruded from the coating die 6 to cover the synthetic resin melted and kneaded by the extruder 7, The laminated body 10 is obtained by cooling in the water tank 8 and cutting into a predetermined length by the cutting machine 9.

By applying the present invention, a resin coating layer can be formed on the inner surface of a metal pipe to obtain a piping material such as a composite pipe having excellent corrosion resistance. As the method, for example, while continuously feeding out a long metal plate, an organic titanate is applied to the inner surface side of the tube with a coating device, and then, in the same manner as in the above continuous production method, it is generally sealed. Steam is passed through the heating device of the structure while supplying steam to form a sintered primer layer, which is formed into a U-shaped cross section with a forming roll, then into a circular cross section with a circular pipe forming machine, and welded with a welding machine to form a circular pipe. After that, the synthetic resin melted and kneaded on the inner surface of the sintered primer layer is extruded from the coating die for coating, and while continuously feeding out a long metal plate, the same procedure as above is performed. After applying the titanate, form a circular pipe with a forming roll, a circular pipe forming machine, or a welding machine in the same manner as in, or after forming a circular pipe, apply organic titanate on the inner surface of the pipe, and then use an internal plug or the like. By passing while supplying water vapor to form a sintered primer layer to a heating apparatus roughly sealed over a certain length in the tube Te,
Synthetic resin is coated in the same manner as in (and is an example of continuous production method.) After applying organic titanate to the inner surface of an existing metal tube by means of brush, spray, etc., both ends of the tube are sealed. To form a sintered primer layer by heating in a state of being filled with water vapor, and then press the kneaded and melted synthetic resin onto the sintered primer layer with a roll or the like, or into a heated and softened synthetic resin tube. Examples thereof include applying internal pressure with air or steam to expand and press-bond the synthetic resin (in this case, an adhesive may be used), (is an example of a batch-type production system), and the like.

The thus-obtained composite pipe is suitable as a hot water supply pipe that is used under repeated cold and heat conditions and a drain pipe for hot waste water.

[Function] A sintered primer layer formed by baking an organic titanate has excellent adhesion to a metal and adhesiveness to a resin coating layer, and many cracks are formed on the surface of the sintered primer layer. To be done.

When a resin coating layer is formed on such a sintered primer layer, the synthetic resin enters the cracks to increase the adhesion area, and the so-called anchor effect is exerted. Good adhesion can be obtained between the resin layer and the resin coating layer, but when the organic titanate coating is sintered in a steam atmosphere, it is better than in the air. However, it was experimentally proved that it was stably obtained.

The reason is that, according to observation with an electron microscope, cracks generated when sintering is performed in a water vapor atmosphere are similar to cracks generated when sintering is performed in air. Compared to the one with a wide width and a small number per unit area, the width is narrow, the number per unit area is large, the opening area ratio is high, and the sintered primer has a complicated shape. It is considered that this is because the adhesion area between the layer and the resin coating layer becomes larger, and the anchor effect is more effectively exhibited.

[0027]

Embodiments of the present invention will be described below with reference to the drawings. (Embodiment) FIG. 2 is a sectional view showing a laminated body of an embodiment of the present invention. 60% of di-i-propoxy bis (acetylacetonato) titanium after degreasing treatment with an alkaline solution and oxide film removal treatment with nitric acid on one side of the steel sheet 11
Apply the isopropanol solution with a brush and apply 90% relative humidity.
In the induction heating type heating device maintained at, the sample was heated at 400 ° C. for 5 minutes to form a sintered primer layer. The thickness of the obtained sintered primer layer 12 was 1 μm.

On the surface of the sintered primer layer 12, 1 part by weight of vinyltrimethoxysilane and 0.01 part by weight of organic peroxide (perbutyl D) were added to 100 parts by weight of polyethylene, and the mixture was kneaded and modified at 190 ° C. The silane-grafted polyethylene was melt-extruded and fused to obtain a laminate 10 having a resin coating layer 13 having a thickness of 2 mm.

Regarding this laminated body 10, JIS K68
According to No. 54 "Test Method for Peeling Adhesive Strength of Adhesive" (however, carried out with a "T-shaped peeling test piece" having a width of 10 mm), the peeling adhesive strength was measured and found to be 20 kgf / 10 mm.

Then, the laminate 10 was subjected to a heating-cooling test in which the operation of immersing the laminate 10 in hot water of 85 ° C. for 5 minutes and then in cold water of 20 ° C. for 5 minutes was repeated 7,000 cycles.
After completion of the test, as a result of observing the presence or absence of peeling between the layers and other abnormalities, peeling and gaps between the steel plate 11 and the sintered primer layer 12 and between the sintered primer layer 12 and the resin coating layer 13, the resin coating layer No contraction of 13 and other abnormalities were observed.

(Comparative Example) An organic titanate coating film was applied at room temperature 2
A laminate was obtained by the same method as in Example 1 except that the laminate was heated and sintered in air at 5 ° C and 30% relative humidity.

With respect to this laminate, the peel adhesion strength was measured by the same method as in Example, and as a result, it was 18 kgf / 10 mm.

Then, a heating-cooling test was conducted in the same manner as in the example. As a result, the resin coating layer was peeled from the end of the laminate to a depth of about 10 mm, and a gap between the steel plate and the resin coating layer was about 10. A gap of 0.5 mm was recognized.

[0034]

As is apparent from the above description, according to the method of the present invention, the sintered primer layer having a large number of fine cracks formed on the surface of the metal can be stably formed. Then, by forming a resin coating layer on this primer layer, even when used under severe conditions such as heating and cooling with hot water and cold water, peeling or a gap between the metal and the resin coating layer, It is possible to obtain a laminate having excellent hot water resistance, corrosion resistance, and durability, in which shrinkage of the resin coating layer does not occur.

[Brief description of drawings]

FIG. 1 is a process explanatory view showing an embodiment of a method of the present invention.

FIG. 2 is a cross-sectional view of a laminated body manufactured by the method of the example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Uncoiler 2 Surface treatment tank 3 Coating device 4 Heating device 5 Steam supply device 6 Coating die 7 Extruder 10 Laminated body 11 Steel plate 12 Sintered primer layer 13 Resin coating layer M Metal plate

Continuation of front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display area C08J 5/12 9267-4F B29K 105: 22

Claims (1)

[Claims] 1. A method for producing a laminate, which comprises applying an organic titanate to a surface of a metal and then heating it to form a sintered primer layer of the organic titanate, and forming a synthetic resin coating layer on the sintered primer layer. A method for manufacturing a laminate, comprising forming a sintered primer layer by heating a metal coated with an organic titanate in a steam atmosphere.