JPH04135025A - Drawing can of resin film laminated surface treating steel sheet and its manufacture - Google Patents

Abstract

PURPOSE:To present the laminated steel can of high quality by laminating polyamid film by using the polyesterurethane system adhesive agent of polyester as the main agent and polyisocyanate as hardening agent to one side surface of the inner side of the steel for the can. CONSTITUTION:In the case the surface treated steel strip is worked to the can, the fluidity of the part of the curved part 3 of the stepped part 2 is largest. The polyesterurethane system adhesive agent is the adhesive agent composed of polyester as main agent and polyisocyanate as hardening agent. The post heat treatment is executed on the condition of the temperature range being able to increase the adhesive ability that the non-stretched normal chain aliphatic polyamid film is not crystalized, that is, not hardened so as not to be able to resist for forming the can. The resin film laminated surface treated steel sheet obtained with this is excellent in forming property, without stripping on the drawing and without degrading (whitening) resin film, so the drawing can of high quality of resin laminated steel sheet can be presented.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a technique for manufacturing cans by drawing from a surface-treated steel plate laminated with a resin film.

(Prior art and problems to be solved) Conventionally, when manufacturing cans from tin plates or chemically treated steel sheets, in order to prevent the metal of the can material from being corroded by the contents of the can, Providing a protective film is widely practiced.

Regarding the protective film of squeeze cans, Japanese Patent Application Laid-Open No. 64-7
0352, JP-A-56-10451, etc. That is, it has a structure in which a coaxially stretched polyethylene terephthalate film is provided on a surface-treated steel plate via an adhesive.

This resin film is used because it has relatively good adhesion and heat resistance compared to other resin films, and various research and developments have been conducted using the above-mentioned publication as an example.

However, when a protective film made of the above-mentioned biaxially stretched polyethylene terephthalate film and adhesive is provided on a tin plate, and a can is formed into the shape shown in Figure 1 by drawing so that the side with the protective film becomes the inner surface. However, there was a drawback that the tin plate and the protective film were peeled off at the bend 3 at the upper end 2 of the side wall 1. Incidentally, when such a pot-shaped can is subjected to steam heat sterilization treatment at 115° C. for 30 minutes, peeling at the above-mentioned locations is more clearly observed.

On the other hand, attempts have also been made to use resin films other than biaxially stretched polyethylene terephthalate films.

First, there is a method of thermally bonding and covering a metal plate with a thermoplastic resin film (or a thermoadhesive resin film), but this method has a problem in that the adhesive strength decreases.

Also, Special Publication No. 60-21544, No. 60-21545
In this issue, in addition to polyethylene resin film, metal oxidation is applied to urethane resin as a common technology for coating thermoplastic resin films (or thermoadhesive resin films) such as polyester resin film, polypropylene resin film, and polyvinyl chloride film. In this method, a metal plate is coated with a resin film of the above type using an adhesive mixed with a powder of aluminum, hydroxide, or aluminum salt. but,
The above-mentioned publication only discloses examples of the above-mentioned resin film, and it is not clear whether there will be a problem of peeling of the resin film in cans after drawing when applied to other types of resin films. do not have.

The present invention was made under the above circumstances, and
The purpose of the present invention is to provide a drawn can made of a resin film laminated surface-treated steel plate that does not cause peeling as described above in any part of the can formed by drawing, and also to provide a method for manufacturing a drawn can. It is something to do.

(Means for Solving the Problem) Biaxially oriented polyethylene terephthalate film is used as a resin film in the prior art because it has relatively adhesive properties compared to other resin films.

Although this is because it has good heat resistance, it still has the problem of peeling as described above. Therefore, research on various adhesives is currently being conducted.

On the other hand, as a result of our efforts to develop a new lamination technology that uses a resin material that has not been demonstrated in the above-mentioned publications as a resin film and does not cause the problem of peeling, we found that It was discovered that an unstretched linear aliphatic polyamide film can be used only in combination with processing, and the present invention was created based on this discovery.

That is, the present invention provides a can formed by drawing a surface-treated steel plate, in which a polyester urethane adhesive consisting of polyester as a main ingredient and polyisocyanate as a hardening agent is applied to one side of the steel plate that becomes the inner surface of the can. The gist of this invention is a resin film-laminated, surface-treated steel sheet draw can, characterized in that an unstretched linear aliphatic polyamide film is laminated using a non-stretched linear aliphatic polyamide film, which is then heat-treated and laminated.

In addition, in the manufacturing method, when producing cans by drawing a surface-treated steel plate, a polyester urethane adhesive consisting of polyester as a main ingredient and polyisocyanate as a hardening agent is applied to one side of the steel plate, and after drying, After adhering an unstretched linear aliphatic polyamide film thereon, a post-heat treatment is performed at a heating temperature of 50° C. or higher and a heating time of 48 hours to 20 seconds, followed by cooling or slow cooling. Then, drawing processing is performed so that one side becomes the inner surface of the can.

The present invention will be explained in further detail below.

(Function) The linear aliphatic polyamide film used in the present invention is a resin well known as so-called [nylon] (trade name),
For example, unstretched nylon 6 film, 6,6 nylon film, 12 nylon film, 6,66 copolymer nylon film, MX nylon film (all trade names), etc. are used. Of course, it goes without saying that the material is not limited to these nylon films.

Such unstretched linear aliphatic polyamide film is produced using a polyester urethane adhesive.

It is laminated on various surface-treated steel plates through the treatment described below.

The thickness of the film is determined as appropriate, for example, 530 μm.
■It's about.

The polyester urethane adhesive used in the present invention is an adhesive consisting of polyester as a main ingredient and polyisocyanate as a curing agent. For example, there are adhesives that use aromatic polyester as a main ingredient and aliphatic isocyanate adducts as a curing agent.Specifically, Dainichiseika Kagyo's E-320 (main ingredient) and C-75N (curing agent) are used. 15=2
Adhesives mixed in the following proportions are used.

The adhesive application method, application amount, drying conditions, etc. can be determined as appropriate. For example, the average application amount is 40mg/dn+”,
The drying temperature is approximately 110°C.

The post-heat treatment is carried out under conditions that can improve the adhesive properties of the adhesive within a temperature range in which the unstretched linear aliphatic polyamide film does not crystallize, that is, harden to the point where it cannot withstand can processing. in particular.

The film is heated at a heating temperature of 50° C. or higher, a heating time of 48 hours to 20 seconds, and a heating time of 48 hours to 20 seconds. After heating, the film is left to cool or gradually cooled. If the melting point of the film is -30°C for 20 seconds or more, it will not withstand can processing, and if it is below 50°C for 48 hours, the adhesiveness will not improve. After heating, rapid cooling (water cooling) is not required, so there is an advantage that no special cooling equipment is required.

When the surface-treated steel sheet is made into a can having the shape shown in Fig. 1, compressive flow occurs in the circumferential direction of the can, and elongated flow occurs in the height direction of the can. It is known that the flow at the bend 3 of the stepped portion 2 is the largest.

According to the present invention, the adhesive strength of the adhesive is improved by post-heat treatment without hardening the film, so that even at the maximum flow point of the surface-treated steel sheet, the adhesive and the film adapt and flow. No peeling occurs between the treated steel plate and the treated steel plate. Furthermore, since the film covers the inner surface of the can without cutting, the protective effect of the film is maintained, and contact between the contents inside the can and the surface-treated steel plate can be reliably prevented.

As the surface-treated steel plate, a steel plate made of an appropriate material and subjected to various surface treatments and having an appropriate thickness is used.

(Example) Next, examples of the present invention will be shown.

S1112 An average of 55 m of epoxy ester paint was coated on one side of a 0.22 mm thick coiled tin plate using coil coating.
g/daz coating, drying, and then apply an average of 40 layers of polyester urethane adhesive on the other side (35 to 5 g/daz).
Immediately after coating and drying at 110°C, a 25μ thick 6 nylon film was applied onto the adhesive at a nip roll temperature of 115°C.

This laminated tin plate was subjected to a post-heat treatment in which it was heated at 50° C. for 2 days and then allowed to cool. As a result, no crystallization (whitening) was observed in the viscous 6-nylon film.

Thereafter, the heat-treated laminated tin plate was drawn so that the 6 nylon film pasting side was the inner surface, and the shape shown in Fig. 1 was obtained, with a bottom diameter (d-1) of 61.05 mm.
, Step diameter (d-2): 71, 70 mm, Opening diameter (d-3): 74.2 Clew, Step height (
h-1): 26.60mm, opening end height (h-2)
: 32.70℃, bottom arc radius (R-1): 3.
A drawing can with 7 crawler layers and step arc radius (R-2) = 1.6 mm was manufactured.

Regarding this squeeze can, first, the peeling condition after molding and retort processing was investigated.

The results are as shown in Table 1. In Example 1 of the present invention, no peeling was observed either after molding or retort processing, and in particular, no peeling was observed at the bent portion 3 of the can. Excellent quality.

On the other hand, the comparative example is an example in which a biaxially oriented polyethylene terephthalate (PET) film was post-heat-treated using the same adhesive and under the same conditions as the inventive example, but some peeling had already occurred after the molding process. After retort treatment, peeling occurred frequently. This means that the combination of the polyester urethane adhesive used in the present invention and the unstretched linear aliphatic polyamide film is a unique combination, and this adhesive is
This shows that even when combined with other resin films such as T, peeling occurs after molding.

Next, the squeeze cans were subjected to various corrosion tests including the most severe corrosion test (i.e., a 3% mixture of common salt, citric acid, and malic acid) and actual can tests under the conditions shown in Table 2. I did it. In the test, various contents were filled into cans, treated under the conditions shown in Table 2, the cans were opened, and the inner surface of the can was examined by a current test.

As shown in Table 2, no peeling was observed in any of the tests, and good results were obtained.

No peeling was observed upon visual inspection.

Section 11 This example differs from Example 1 only in the method of post-heating treatment. That is, post-heat treatment was performed at 170° C. for 20 seconds.

A drawn can with the same shape and dimensions as in Example 1 was manufactured from this tin plate, and the peeling condition was examined in the same manner. As a result, 11111 was not observed anywhere on the can, and no peeling was observed in actual can tests. Good results were obtained.

After applying adhesive and a nylon film on one side of a coil tin plate in the same manner as in Example 1, a thermosetting epoxy phenol paint was applied on the nylon film.
Dry at 50°C for 10 minutes. Next, apply epoxy ester white paint to the other side, bake dry at 170°C for 10 minutes, print on top, and paint at 150°C for 10 minutes.
Baking drying was carried out for 0 minutes, and then an epoxy ester paint was applied thereon and baking drying was carried out at 170° C. for 10 minutes.

A drawn can with the same shape and dimensions as in Example 1 was manufactured from this tin plate, and the peeling condition was examined in the same manner. As a result, no peeling was observed anywhere on the can. In No. 1, an unstretched 6,6 nylon film was used instead of the unstretched 6,6 nylon film.

Peeling tests were conducted on squeeze cans manufactured using 12 nylon film, 6,66 cobolymer nylon film, and MX nylon film (all trade names) and with different post-heat treatment conditions, and no peeling was observed in all of them. I couldn't.

An example of the results is shown in Table 2.

Note that the post-heating temperature and time in each example are each a preferable example, and any temperature and time that do not substantially change the quality of the nylon film and improve the adhesive strength of the adhesive to an extent that does not cause peeling may be used. Needless to say, either condition can be applied.

For example, when the post-heat treatment conditions are changed as shown in Table 3, the relationship with moldability is as shown in the table.

(Effects of the Invention) As detailed above, one aspect of the present invention is to use an unstretched linear aliphatic polyamide film as a resin film to be laminated on a surface-treated steel sheet using a specific adhesive (polyester as a main ingredient and polyester as a hardening agent). Since the resin film laminated surface-treated steel sheet obtained has excellent moldability, it can be formed by drawing process. Since peeling does not occur at any part of the can and there is no deterioration (whitening) of the resin film, it is possible to provide a high-quality drawn can made of a surface-treated steel sheet laminated with a resin film.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing the shape of a squeeze can. Patent Rogenjin Yamato Seikan Co., Ltd.

Claims (2)

[Claims] (1) In a can formed by drawing a surface-treated steel sheet, a polyester urethane adhesive consisting of polyester as a main ingredient and polyisocyanate as a hardening agent is used on one side of the steel sheet that becomes the inner surface of the can. A drawn can made of a resin film laminated surface-treated steel sheet, characterized in that a stretched linear aliphatic polyamide film is laminated by being pasted and then heat-treated. (2) When producing cans by drawing a surface-treated steel sheet, a polyester urethane adhesive consisting of polyester as a main ingredient and polyisocyanate as a hardening agent is applied to one side of the steel sheet, and after drying, no adhesive is applied on it. After pasting the stretched linear aliphatic polyamide film, the heating temperature was 5.
0℃ or above and below the melting point of the film, heating time is 48 hours to 2
Manufacture of a drawn can made of a resin film laminated surface-treated steel sheet, which is characterized by heating for 0 seconds and then allowing it to cool or slow cooling, followed by heat treatment, and then drawing with one side facing the inner surface of the can. Method.