JP3917765B2 - Thermoplastic resin laminated metal plate for containers with excellent high-speed moldability - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
TECHNICAL FIELD The present invention relates to a thermoplastic resin laminated metal plate for metal containers, and in particular, a thermoplastic resin laminate for drawn cans, squeezed irons and thinned deep drawn cans, which generate a large amount of heat during processing of the container. It relates to a metal plate.
[0002]
[Prior art]
Conventionally, the inner surface of metal cans has been generally painted to prevent corrosion, but development has been carried out to use a metal plate laminated with thermoplastic resin on the surface without using organic solvents as the metal plate for containers. It is. (1) A method of laminating a biaxially oriented polyethylene terephthalate film through a low-melting polyester adhesive layer and using it as a can-making material (JP 56-10451, JP-B 1-192546, etc.), (2) A method of laminating an amorphous or low crystallinity aromatic polyester film on a metal plate and using it as a can-making material (JP-A-1-192545, JP-A-2-57339, etc.), (3) A method of laminating a low-orientation polyethylene terephthalate film on a metal plate and using it as a can-making material (Japanese Patent Laid-Open No. 64-22530) etc. Methods (JP-A-6-297644, JP-A-6-320658, etc.) have been proposed.
[0003]
However, there has been a problem when molding at high speed. In particular, when molding is performed with a large amount of heat generation such as molding of a squeezed iron can and at a high speed exceeding 200 cans per minute, the molded can does not come out of the processing punch, and continuous molding is possible. There is a case where a phenomenon called punching defect which becomes impossible may occur. For this reason, it is a problem because stable high-speed can production cannot be performed and productivity is lowered.
[0004]
[Problems to be solved by the invention]
This invention is made | formed in view of the said situation, and it aims at providing the thermoplastic resin laminated metal plate excellent in the moldability in high speed, especially punch punching property.
[0005]
[Means for Solving the Problems]
The present invention has been made to solve the above problems,
(1) Excellent high-speed moldability characterized by having a thermoplastic resin film having an immersion depth of 12 μm or less at 200 ° C. measured by thermomechanical analysis on at least a metal plate surface which is an inner surface of a container Thermoplastic resin laminated metal plate.
(2) The thermoplastic resin laminated metal plate having excellent high-speed moldability as described in (1) above, wherein the thermoplastic resin is mainly a polyester composition.
[0006]
The present invention is described in detail below.
The resin film on the surface of at least the inner surface of the container of the thermoplastic resin laminated metal plate in the present invention is measured at 200 ° C. by thermomechanical analysis in order to ensure excellent high-speed moldability, in particular punch punchability. It is important that the immersion depth is 12 μm or less.
It is considered that the punch defect is caused by the resin film being softened by the processing heat and the resin sticking to the surface of the punch. In particular, during high speed forming, the processing heat dissipation of the metal plate is smaller than the processing speed, so the temperature of the metal plate rises and the temperature of the resin film also rises. It is done.
[0007]
The softening of the resin film not only depends on the melting point or glass transition point of the resin film, but also varies greatly depending on the composition of the resin film, the molecular weight, the film structure such as the multilayering of the film and the composite of the film and the dispersion state. Attention was paid to the relationship between the softening of the resin film during heating and punch punchability during high-speed molding, and various studies were conducted to achieve the present invention. Preferably, the immersion depth at 200 ° C. is 10 μm or less. Some are desirable.
The relationship between the immersion depth of the resin film and high-speed moldability is shown in FIG. As is clear from FIG. 1, the high-speed moldability is good when the immersion depth is 12 μm or less, and even better when it is 10 μm or less. The reason for this is not clear, but the surface of the punch is not completely smooth and has unevenness. A resin with a deep immersion depth will cause the resin to bite into the irregularities, so high-speed moldability will deteriorate, but a resin with a low immersion depth may be presumed to be difficult to do this. Yes.
[0008]
As shown in FIG. 2, the immersion depth according to the thermomechanical analysis in the present invention increases the temperature range from 30 ° C. to 250 ° C. by applying a load of 30 mN to a quartz probe having a flat tip and a 1 mmφ shape. Measurement can be performed at a temperature rate of 20 ° C./min, and can be determined from the difference in probe position between 30 ° C. and 200 ° C. 2A is a front sectional view of the tip shape of the quartz glass probe used for measuring the immersion depth of the thermomechanical analysis, the sample, and the sample holder, and FIG. 2B is a sectional view of the quartz glass probe. It is a cross section.
As a method of adjusting the immersion depth, there are a method of adjusting the average particle diameter of the resin dispersion layer, a method of adjusting the thickness of each of the different resin types as a multilayer, and the like.
[0009]
A steel plate, a surface-treated steel plate, an aluminum plate, an aluminum alloy plate, or the like can be used as the metal plate serving as a base material of the thermoplastic resin laminated metal plate of the present invention. Although not particularly limited, as a steel sheet, usually plate thickness t _0: the range of 0.12～0.60Mm, it is desirable to have a hardness (HR30T) 46~7.
The surface of this steel sheet is plated with one or more of Sn, Cr, Ni, Al, Zn, and the adhesion, workability, and corrosion resistance are eliminated on the chromate-treated film to eliminate the need for coating. It is desirable that an excellent resin film is laminated.
[0010]
As a specific example, the adhesion amount 0.5 to 5.0 g / tin-plated steel sheet subjected to post-chemical conversion tin plating m ² coating weight 0.3 to 2.0 g / m ² of facilities and after chemical conversion treatment Nickel plating Nickel plated steel sheet, Sn / Ni plating, with 0.5 to 2.0 g / m ² and 0.01 to 0.5 g / m ² of Ni and Sn, respectively, as post-plating chemical conversion treatment in this order There is a steel plate, a chromium-chromate treated steel plate called normal TFS (Tin Free Steel) having a metal Cr adhesion amount of 50 to 200 mg / m ² and a Cr oxide oxide of 5 to 30 mg / m ² .
[0011]
The aluminum plate used in the present invention is usually in the range of plate thickness t ₀ : 0.18 to 0.60 mm, and the alloy composition is 5052, 5082, 5182, 5352, 5349, 5017 series. The tempering is preferably H19. A surface-treated metal plate obtained by subjecting this aluminum plate to chromate treatment, zircomate treatment or phosphoric acid-chromic acid chemical conversion treatment can also be used.
[0012]
Examples of the resin film in the present invention include polyester resins, nylon resins, olefin resins such as polyethylene and polypropylene, ethylene-vinyl acetate copolymers, modified olefin resins such as ionomers, polyvinyl alcohol and copolymers thereof, and acrylic resins. Examples thereof include a single layer and a multilayer film of a resin composed of a simple substance and a mixture thereof.
[0013]
Among them, the polyester composition is preferred mainly from the viewpoint of cost and flavor. Although it does not specifically limit as a polyester composition, The following examples can be given as a typical thing. Acid components include aromatic dibasic acids such as terephthalic acid, isophthalic acid and naphthalenedicarboxylic acid, aliphatic dicarboxylic acids such as adipic acid, sebacic acid, azelaic acid and dodecadioic acid, dimer acid and cyclohexanedicarboxylic acid. Examples thereof include alicyclic dicarboxylic acids. Examples of the alcohol component include aliphatic diols such as ethylene glycol, diethylene glycol, butanediol, and hexanediol. These are used in combination of one or more. For example, as a preferable example, a polyester composition comprising 75 mol% or more of terephthalic acid as an acid component and 85 mol% or more of ethylene glycol as an alcohol component can be mentioned.
[0014]
For example, from the viewpoint of improving the impact resistance, the resin film has a two-layer structure with an adhesive layer as the surface layer, and a structure in which an impact-absorbing resin such as polyolefin resin or styrene butadiene rubber is dispersed in the adhesive layer. preferable.
Moreover, the resin film thickness in this invention is although it does not specifically limit, About 2-80 micrometers is suitable, Preferably it is 8-60 micrometers, More preferably, it is the range of 12-40 micrometers. The thickness ratio between the surface layer and the adhesive layer is not particularly limited, but the thickness of the surface layer is preferably 1 to 10 μm.
[0015]
【Example】
Examples of the present invention and comparative examples will be described.
Example 1
It has a tin plating layer with an adhesion amount of 2.8 g / m ² on one surface, and Sn and Ni adhesion amounts on the other surface of 0.5 to 2.0 g / m ² and 0.01 to 0.5 g, respectively. / a m ² Ni, steel sheet having a Sn / Ni plating layer plated after chemical conversion treatment in the order of Sn in Sn / Ni plated layer surface of the {thickness 0.24 mm, hardness (HR30T) 61}, 2 layers of thickness 30μm A polyester film having a structure (a surface layer was 3 μm and an adhesive layer was 27 μm) was laminated. Both the surface layer and the adhesive layer were polyesters composed of terephthalic acid, isophthalic acid and ethylene glycol, and styrene butadiene rubber was dispersed in the adhesive layer as an impact absorbing resin with an average particle diameter of 0.2 μm and 10 wt%. The melting point of the surface layer was 230 ° C., and the melting point of the adhesive layer was 215 ° C. The immersion depth by thermomechanical analysis was 7 μm.
With a resin film on the inner surface of the can, in a production facility for drawn and drawn cans by drawing twice and three times, forming a continuous 2,500 cans at a can-making speed of 2.50 cans / min. Evaluated. The molding conditions were a blank diameter of 126 mm, a one-stage drawing ratio of 1.75, a two-stage drawing ratio of 1.35, an ironing punch diameter of 52.80 mm, and a total ironing ratio of 67%. The high-speed moldability was good without problems.
[0016]
(Example 2)
A polyester film having a melting point of 220 ° C. composed of a single layer of terephthalic acid, isophthalic acid and ethylene glycol having a thickness of 20 μm was laminated on one surface of an aluminum plate of 0.26 mm thickness and 5017 series alloy. The immersion depth by thermomechanical analysis was 9 μm. The same high-speed moldability test as in Example 1 was performed, and the high-speed moldability was satisfactory without problems.
[0017]
(Example 3)
A single-layer polyamide film (nylon 6, melting point 220) film having a thickness of 25 μm was laminated on the Sn / Ni plating layer surface of the same steel plate as in Example 1. The immersion depth by thermomechanical analysis was 10 μm.
The same high-speed moldability test as in Example 1 was performed, and the high-speed moldability was satisfactory without problems.
[0018]
Example 4
A polyester film having a two-layer structure with a thickness of 35 μm (a surface layer of 3 μm and an adhesive layer of 32 μm) was laminated on the Sn / Ni plating layer surface of the same steel plate as in Example 1. Both the surface layer and the adhesive layer were polyesters composed of terephthalic acid, isophthalic acid and ethylene glycol, and styrene butadiene rubber was dispersed in the adhesive layer as an impact-absorbing resin at an average particle diameter of 0.2 μm and 15 wt%. The melting point of the surface layer was 230 ° C., and the melting point of the adhesive layer was 220 ° C. The immersion depth by thermomechanical analysis was 12 μm.
The same high-speed moldability test as in Example 1 was conducted, and the punch-out property was at a level having no practical problem, and continuous molding was possible.
[0019]
(Comparative Example 1)
On the Sn / Ni plating layer surface of the same steel plate as in Example 1, a 30 μm thick two-layer polyester film (the surface layer was 2 μm and the adhesive layer was 28 μm) was laminated. Both the surface layer and the adhesive layer were polyesters composed of terephthalic acid, isophthalic acid and ethylene glycol, and styrene butadiene rubber was dispersed in the adhesive layer as an impact-absorbing resin at an average particle size of 0.3 μm and 15 wt%. The melting point of the surface layer was 230 ° C., and the melting point of the adhesive layer was 215 ° C. The immersion depth by thermomechanical analysis was 14 μm.
The same high-speed moldability test as in Example 1 was performed, but the punch-out property was poor and continuous molding could not be performed.
[0020]
【The invention's effect】
As described above, the thermoplastic resin laminated metal plate of the present invention is excellent in punch pull-out property at high speed forming, and can provide a material capable of producing a container made of a thermoplastic resin laminated metal plate at high speed and efficiently. .
[Brief description of the drawings]
FIG. 1 is a diagram showing the relationship between the depth of immersion in thermomechanical analysis and the high-speed moldability (punching ability) of a drawn and ironed can.
FIG. 2 is a diagram of a tip shape, a sample, and a sample holder of a quartz glass probe used for measuring an immersion depth of a thermomechanical analysis defined in the present invention.
[Explanation of symbols]
1 Probe made of quartz glass 2 Sample 3 Thermoplastic resin film 4 Metal plate 5 Sample holder

Claims (2)

A thermoplastic resin excellent in high-speed moldability, characterized in that it has a thermoplastic resin film having an immersion depth of 12 μm or less at 200 ° C. measured by thermomechanical analysis on at least the metal plate surface which is the inner surface of the container Laminated metal plate. The thermoplastic resin-laminated metal sheet having excellent high-speed moldability according to claim 1, wherein the thermoplastic resin is mainly a polyester composition.

Images