JPH07232402A - Laminated body and manufacturing method thereof - Google Patents

Abstract

(57) [Abstract] [Purpose] Corrosion resistance and heat resistance without the silane-grafted polyolefin layer peeling from the surface of the metal body even under severe conditions such as high temperature hot water or the temperature difference between the inside and the outside. Provided are a laminate having excellent properties and moldability, and a method for producing the same. [Structure] A laminated body in which a plurality of organic titanate sintered layers 2 and silane-grafted polyolefin layers 3 are alternately provided in this order on the surface of a metal body 1, the outermost layer of which is a silane-grafted polyolefin layer 3. .

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminate having excellent corrosion resistance, heat resistance and moldability, and a method for producing the same.

[0002]

2. Description of the Related Art Hitherto, there has been known a laminated body in which a synthetic resin layer is formed on the surface of a metal body in order to improve the corrosion resistance of the metal body. Polyolefin is often used for the synthetic resin layer of such a laminate, and examples of the use of the laminate include roofing materials, wall materials, automobile members, and resin-coated metal pipes. In such a laminate, in order to improve the adhesiveness between the metal body and the synthetic resin layer, a polyolefin obtained by modifying a polyolefin with a hydrolyzable silane as a synthetic resin layer, that is, a steel pipe coated with a silane-grafted polyolefin is disclosed. (Japanese Patent Application Laid-Open No. 2-76960).

However, when the above steel pipe is used for a long period of time under severe conditions in which the flow of hot water and the contact between hot water and cold water are repeated, water diffuses in the silane-grafted polyolefin layer to form a metal body. Reach the interface.
The water reaching such an interface causes rust in the metal body, lowers the adhesive strength between the metal body and the silane-grafted polyolefin layer, and the silane-grafted polyolefin layer peels from the metal body. It was

As a method of solving such a problem,
Applying organic titanate as a primer layer on the metal surface
A laminated body in which a synthetic resin layer made of silane-crosslinked polyethylene is formed by sintering is disclosed (Japanese Patent Application Laid-Open No. Hei 5 (1999) -58242).
No. 169585). However, when the laminate is used for a long period of time in hot water or in an environment where there is a difference in temperature between the inside and the outside, moisture diffuses and permeates the synthetic resin layer and reaches the interface with the primer layer. Moisture that reaches the interface with the primer layer gradually diffuses and permeates the primer layer and reaches the interface with the metal, causing rust on the metal, which reduces the adhesive strength between the metal and the synthetic resin layer. Then, there is a problem that the synthetic resin layer is separated from the metal surface.

In order to solve such a peeling problem, there has been disclosed a laminate in which an inorganic filler is added to a synthetic resin to greatly suppress the diffusion / permeation amount of water in the synthetic resin layer. (JP-A-5-169585). However, this laminated body has a greater effect of suppressing the diffusion and permeation of water as the amount of the inorganic filler added increases, but the viscosity of the synthetic resin increases and the moldability decreases, and the dispersion of the inorganic filler increases. As a result, the performance is deteriorated and stable performance cannot be obtained.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object thereof is even under severe conditions where there is a temperature difference between high temperature hot water and inner and outer surfaces. Another object of the present invention is to provide a laminate which is free from peeling of the silane-grafted polyolefin layer from the surface of the metal body and has excellent corrosion resistance, heat resistance and moldability, and a method for producing the same.

[0007]

A laminated body according to claim 1, wherein a plurality of organic titanate sintered layers and silane-grafted polyolefin layers are alternately provided on the surface of the metal body, and the surface layer is a silane-grafted polyolefin layer. Is.

Examples of the above-mentioned metals include those generally called metals such as iron, steel, stainless steel, aluminum, copper, zinc and the like, and the metal body is not limited to a plate-like one, but a tube, a rod, and others. The thing of a shape is mentioned.

In order to improve the adhesiveness with the organic titanate sintered layer described later, the metal body is sandblasted,
It is preferable to perform etching with hydrochloric acid, nitric acid, hydrochloric acid or the like, rust removal, or degreasing treatment with sodium silicate or the like.

The above-mentioned silane-grafted polyolefin is obtained by mixing a silane coupling agent and an organic peroxide with polyolefin and heating and melting the mixture. As the above-mentioned polyolefin, polyethylene such as high-density polyethylene, medium-density polyethylene, low-density polyethylene, linear low-density polyethylene; polypropylene; polybutene and the like can be used.

Examples of the silane coupling agent include hydrolyzable methoxyl group, ethoxyl group, β-
A compound having an alkoxyl group such as a methoxyethoxy group or a chloro group and having a double bond site that reacts with a free radical site generated in a polyolefin such as a vinyl group, an acryl group or a methacryl group in the same molecule is exemplified. To be

The reason why the silane coupling agent requires a hydrolyzable functional group in its molecule is that it is essential for bonding and adhering to a metal body or an organic titanate sintered layer. The reason why the silane coupling agent requires a double bond site in its molecule is that the polyolefin easily reacts with the radical site generated by heating with the organic peroxide to cause a graft reaction. is there.

Examples of the silane coupling agent include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriacetoxysilane, γ-methacryloxypropyltrimethoxysilane and the like.

Examples of the organic peroxide include dimethyl peroxide, di-t-butyl peroxide, dicumyl peroxide, dipropionyl peroxide, benzoyl peroxide, t-butyl hydroperoxide, cumene hydroperoxide and the like. Can be mentioned.

The silane-grafted polyolefin layer is
It is formed from a silane-grafted polyolefin sheet or film, and its thickness is preferably 5 mm or less so that a large stress is not applied to the organic titanate sintered layer described below when laminated.

The above organic titanate sintered layer is used as a primer layer, and a silane-grafted polyolefin layer is provided on the surface of the primer layer.

Examples of the organic titanate include an organic group (for example, a hydrolyzing group such as an isopropyl group) bonded to an inorganic substance in the molecule and an organic group having an affinity for the organic substance (for example,
Stearoyl group, N-aminoethyl-aminoethyl group,
Those having an organic group such as dodecylbenzenesulfonyl group are preferably used. Examples of such an organic titanate include isopropyl (N-aminoethyl-
Aminoethyl) titanate, ethyl tri (N-aminoethyl-aminoethyl) titanate, diisopropyldi (N-aminoethyl-aminoethyl) titanate, butyl tri (N-aminoethyl-aminoethyl) titanate, dibutyldi (N-aminoethyl-amino) Ethyl) titanate, tetra-n-butoxy titanium, tetra (2-
Examples thereof include ethylhexyloxy) titanium, tetra-i-propoxy titanium, di-i-propoxy bis (acetylacetonato) titanium, di-n-butoxy bis (triethanolaminato) titanium and the like.

Of the above-mentioned organic titanates, those in which two hydrolyzable groups and two organic groups having an affinity for organic substances are bonded to Ti atoms are preferable. Examples of such an organic titanate include, for example, di-i-propoxy bis. (Acetylacetonato) titanium, di-n-butoxy bis (triethanolaminato) titanium and the like can be mentioned.

Examples of commercially available products of the organic titanate include “Planeact” manufactured by Ajinomoto Co., Inc. and “Citacoat” manufactured by Nippon Soda Co., Ltd.

As a method for forming the above organic titanate sintered layer, the organic titanate is applied to the surface of the metal body by a usual application means such as a roll, a brush, a coating rod and a spray, and then the coating film is burner heated and blown with hot air, 200 ° C or higher, preferably 230 to 420 by induction heating or the like
Examples include a method of sintering at ° C.

If the thickness of the organic titanate sintered layer is thin, the effect of suppressing water diffusion is insufficient, and if it is thick, cracks or cracks are likely to occur when bending, stretching or the like is performed. The thickness is preferably 0.01 to 100 μm, more preferably 5 to 50 μm.

To produce the laminate of the present invention, for example,
The following methods are available. (1) First, as shown in FIG. 1, a composite sheet 11 is obtained by forming an organic titanate sintered layer 2 by coating and baking organic titanate on one surface of a silane-grafted polyolefin sheet by spraying or the like. A plurality of the composite sheets 11 are placed on the surface of the metal body 1 so that the organic titanate sintered layer 2 and the metal body 1 face each other, and then thermocompression bonding is performed. As a result, as shown in FIG. A plurality of laminated layers in which the sintered layers 2 and the silane-grafted polyolefin layers 3 are alternately laminated and the surface layer is the silane-grafted polyolefin layers 3 are obtained.

(2) After applying an organic titanate on the surface of the metal body 1 shown in FIG. 2 and baking it to form an organic titanate sintered layer 2, a silane-grafted polyolefin sheet is placed on the sintered layer 2 and heated. Laminated by pressure bonding to form the silane-grafted polyolefin layer 3. Next, the organic titanate is applied onto the silane-grafted polyolefin layer 3 and baked to form the organic titanate sintered layer 2. By repeating these steps in sequence, a plurality of layers of the organic titanate sintered layers 2 and the silane-grafted polyolefin layers 3 are alternately laminated to obtain a laminate having the silane-grafted polyolefin layer 3 as the surface layer.

Next, the tubular laminate according to claim 2 will be described. The laminate of claim 2 is a tubular laminate in which a plurality of organic titanate sintered layers and silane-grafted polyolefin layers are alternately provided on the inner surface of the metal tube in this order.

The metal pipe is not particularly limited, and examples thereof include an iron pipe, a steel pipe, a stainless pipe, an aluminum pipe, a copper pipe, and a zinc pipe.

In order to improve the adhesiveness with the organic titanate sintered layer described later, the metal tube is sandblasted,
It is preferable to perform etching with hydrochloric acid, nitric acid, hydrochloric acid or the like, rust removal, or degreasing treatment with sodium silicate or the like.

The silane-grafted polyolefin used is the same polyolefin as used in claim 1,
It is obtained by the same method as in claim 1.

In the tubular laminate according to the second aspect, for example, a composite sheet having an organic titanate sintered layer on one surface of a silane-grafted polyolefin layer is spirally wound so that the organic titanate sintered layer is on the inside. It is obtained by stacking on the inner surface of the metal tube.

In the above-mentioned tubular laminate, the number of layers of the silane-grafted polyolefin layer and the organic titanate sintered layer is appropriately determined according to the required performance and the surface layer is a silane-grafted polyolefin layer.

Next, a method for manufacturing the tubular laminate according to claim 3 will be described. The manufacturing method according to claim 3, wherein a silane-grafted polyolefin sheet having an organic titanate sintered layer on one surface thereof is wound around a tubular core several times, and a wound body is inserted into the metal tube, and then the metal tube is reduced in diameter. It is characterized by doing.

As a method for obtaining the above-mentioned tubular laminate, first, as shown in FIG. 3, one side of the silane-grafted polyolefin sheet 3 is coated with an organic titanate by a spray 12 and then heat-baked in a baking zone 13. After forming the composite sheet 11 having the organic titanate sintered layer 3, the composite sheet 11 is wound around the tubular core body 4 multiple times (twice or more) so that the silane-grafted polyolefin sheet layer 3 is on the inner side. And the wound body 5 is formed.

Next, this wound body 5 is inserted into a metal tube 6 having an inner diameter slightly larger than the outer diameter of the wound body 5, as shown in FIG. At this time, the inner surface of the metal tube 6 may be subjected to degreasing treatment with an alkaline solution or etching treatment with nitric acid. Further, the metal tube 6 is heated while being reduced in diameter from the outer surface of the metal tube 6, the wound body 5 is melted and laminated on the inner surface of the metal tube 6, and then the tubular core body 4 is pulled out, so that the metal A tubular laminate in which the organic titanate sintered layer 3 and the silane-grafted polyolefin layer 2 are laminated on the inner surface of the tube 6 and the surface layer is the silane-grafted polyolefin layer 2 is obtained.

As a method of reducing the diameter of the metal tube 6, a method of applying uniform pressure from the outer surface of the metal tube 6 to compress it or a method of uniformly stretching the metal tube 6 in the tube axis direction is used. In practice, for example, a stretching / induction heating device can be used to perform the diameter reduction and the heating in the same device.

By the above heating, the silane-grafted polyolefin layer 2 of the wound body 5 is melted and fused with the metal tube 6 and the organic titanate sintered layer 3. The heating temperature during fusion is
If it becomes lower, the silane-grafted polyolefin layer 2 will not be sufficiently fused to the metal tube 6, and if it becomes higher, the silane-grafted polyolefin layer 2 will be thermally deteriorated.

[0035]

In the laminate of the present invention and the tubular laminate of the present invention 2, the organic titanate is sintered to form a sintered layer (primer layer) of the organic titanate mainly containing titanium oxide on the surface of the metal body. It This organic titanate sintered layer firmly adheres to the metal body, has strong water repellency, suppresses the diffusion of water, and has an excellent antioxidant property, and thus prevents the surface of the metal body from being rusted. Further, since the organic titanate sintered layer is firmly adhered to the silane-grafted polyolefin layer, peeling between both layers is unlikely to occur. In the method for producing a tubular laminate of the present invention 3, since the wound body of the organic titanate sintered layer and the silane-grafted polyolefin layer is laminated on the inner surface of the metal tube, a laminate having a multilayer structure can be produced by a relatively simple process. Becomes

[0036]

EXAMPLES Examples of the present invention will be described below. (Example 1) 100 parts by weight of linear low-density polyethylene,
Kneading 1 part by weight of vinyltrimethoxysilane and 0.01 part by weight of di-t-butyl peroxide at 190 ° C.,
A silane-grafted polyethylene sheet having a thickness of 300 μm was prepared. Di-i-propoxy bis (acetylacetonato) was added to the above silane-grafted polyethylene sheet.
Titanium ("Citacoat T-50" manufactured by Nippon Soda Co., Ltd.) 60
After applying a weight% isopropanol solution with a brush and air-drying, another silane-grafted polyethylene sheet is placed on this coated surface and heated at 230 ° C for 7 minutes to form an organic titanate sintered layer and fuse both sheets together. A laminate was obtained. The thickness of the entire laminate was 560 μm, and the thickness of the organic titanate sintered layer was 1 μm.

(Comparative Example 1) The same procedure as in Example 1 was carried out except that no organic titanate sintered layer was formed by using a solution of di-i-propoxy bis (acetylacetonato) titanium in 60% by weight of isopropanol. , Thickness 560
A μm laminate was obtained.

[Measurement of Moisture Permeability of Laminate] Regarding the laminates obtained in Example 1 and Comparative Example 1 above, a fully automatic steam tester (“L80-4000 type” manufactured by Lyssy Co.) was used and JIS Z0208 was used. The water permeability was measured in conformity with the results shown in Table 1. One of the laminates was placed under the conditions of 40 ° C. and RH 90%, and the other was placed at 40 ° C. and RH 0%, and the water permeability after 25, 50, 100, 150 and 200 hours was measured.

[0039]

[Table 1]

(Example 2) On one side of a steel sheet that had been degreased with an alkaline solution and etched with nitric acid,
A 60 wt% isopropanol solution of di-i-propoxy bis (acetylacetonato) titanium was applied with a brush and then heated and sintered at 400 ° C. for 10 minutes to form an organic titanate sintered layer having a thickness of 5 μm. Then, on the surface of the above-mentioned sintered layer, 1 mm obtained by the same method as in Example 1 was obtained.
A thick silane-grafted polyethylene sheet was heat fused at 200 ° C. Further, an organic titanate sintered layer having a thickness of 5 μm was formed on this silane-grafted polyethylene sheet in the same manner as above, and then a 1 mm-thick silane-grafted polyethylene sheet was heat-fused at 200 ° C. to obtain a laminate.

Example 3 A silane-grafted polyethylene sheet having a width of 5 m and a thickness of 0.2 mm obtained in the same manner as in Example 1 was coated with di-i-propoxy bis (acetylacetonato) titanium on one side. After spray coating a 60 wt% isopropanol solution, 120 ° C. in the baking zone,
It was heated for 60 minutes to form an organic titanate sintered layer having a thickness of 1 μm. Then, the silane-grafted polyethylene sheet having the organic titanate sintered layer was wound around a Teflon-coated tubular core having a diameter of 80 mm so that the sintered layer was on the outside, and 10 layers were formed. A wound body was obtained.

This rolled body is inserted into a steel pipe (thickness 2 mm, inner diameter 86 mm, length 5 m) that has been subjected to degreasing treatment with an alkaline solution and etching treatment with nitric acid, and then the steel pipe is stretched and induction-heated. The outer surface of the tube was heated to 230 ° C. while being stretched by, and the silane-grafted polyethylene sheet was fused and laminated on the inner surface of the steel tube. Next, this tubular core was pulled out by a core removing device to obtain a tubular laminate.

(Comparative Example 2) In the same manner as in Example 2, a 2 mm thick silane-grafted polyethylene sheet obtained in the same manner as in Example 1 was applied to a steel plate on one side of which an organic titanate sintered layer having a thickness of 10 μm was formed. Was heated and laminated at 200 ° C. to obtain a laminate.

[Evaluation of Performance of Laminated Body] The following performance evaluation was performed on the laminated bodies obtained in Examples 2 and 3 and Comparative Example 2, and the results are shown in Table 2. (1) Peeling Adhesive Strength According to JIS K6854, the peeling adhesive strength between the organic titanate sintered layer and the silane-grafted polyethylene layer was measured. (2) Heating-cooling test A step of immersing the laminated body in hot water of 85 ° C for 5 minutes and then in cold water of 20 ° C for 5 minutes is defined as one cycle, and this step is referred to as 1
After repeating 10,000 cycles, the presence or absence of peeling, floating, swelling, discoloration due to rust between the layers of the laminate was visually confirmed.

[0045]

[Table 2]

[0046]

INDUSTRIAL APPLICABILITY The laminate of the present invention and the tubular laminate of the present invention 2 have the above-mentioned constitutions and are excellent in the adhesiveness between layers, the corrosion resistance and the heat resistance. Even under severe conditions such as a temperature difference, the silane-grafted polyolefin layer does not peel off from the surface of the metal body, and rust hardly occurs on the metal body. Further, the tubular laminate manufacturing method of the present invention 3 is a relatively simple manufacturing process in which a laminated body of the organic titanate sintered layer and the silane-grafted polyolefin layer is laminated on the inner surface of the metal tube to form a multilayer laminated body. Can be manufactured in.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing a composite sheet having an organic titanate sintered layer on one surface of a silane-grafted polyethylene sheet.

FIG. 2 is a schematic cross-sectional view showing an example of the laminate of the present invention.

FIG. 3 is a schematic diagram showing a manufacturing process of a manufacturing method of the present invention 3.

FIG. 4 is a schematic view showing a manufacturing process of a manufacturing method of the present invention 3.

FIG. 5 is a schematic cross-sectional view showing a tubular laminate obtained by the manufacturing method of the third invention.

[Explanation of symbols]

1 Metal Plate 2 Sintered Organic Titanate Layer 3 Silane Grafted Polyethylene Sheet, Silane Grafted Polyethylene Layer 4 Tubular Core 5 Rolled Body 6 Metal Tube 7 Diameter Reduction / Heating Device 8 Core Removal Device 11 Composite Sheet

Claims (3)

[Claims] 1. A laminate having a plurality of organic titanate sintered layers and silane-grafted polyolefin layers alternately provided in this order on the surface of a metal body, the surface layer being a silane-grafted polyolefin layer. Characteristic laminate. 2. A tubular laminate having a plurality of organic titanate sintered layers and silane-grafted polyolefin layers alternately provided in this order on the inner surface of a metal tube, the surface layer of which is a silane-grafted polyolefin layer. A tubular laminate characterized by being present. 3. A method for producing a tubular laminate in which a plurality of organic titanate sintered layers and silane-grafted polyolefin layers are alternately provided in this order on the inner surface of a metal tube, wherein the organic titanate sintered layer is provided on one side. The silane-grafted polyolefin sheet having the organic titanate sintered layer is wound on the tubular core several times to form a wound body, and the wound body is inserted into the metal tube, and then the metal tube is contracted. A method for producing a tubular laminate, which comprises heating a diameter to laminate a wound body and a metal tube, and then pulling out a tubular core body.