JPS5953133B2 - Method for manufacturing fluorine-based resin-coated aluminum utensils - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing fluororesin-coated aluminum utensils, and more specifically, to a method for manufacturing fluororesin-coated aluminum utensils that have a thin wall and a shallow bottom that are difficult to deform.

Fluororesin-coated aluminum utensils have been widely used in various kitchen utensils and other applications because of their excellent non-stick properties and durability. However, coating with fluororesin is generally carried out at high temperatures, and since the aluminum metal is annealed and softened under these conditions, there are various restrictions on the shape of the vessels. In other words, the manufacturing of fluororesin-coated aluminum utensils is generally divided into two methods: one is to coat an aluminum-based metal base material shaped into a container shape with a fluorine-based resin, and the other is to coat a flat aluminum-based metal base material with a fluorine-based resin. However, in the case of the former method, the effects of the above-mentioned annealing appear directly on the product, so basic measures must be taken to avoid deformation during use. It is necessary to increase the thickness of the material, and if the latter method is used, the hardness of deep-bottomed vessels can be recovered to some extent by work hardening during molding, but the work deformation q
In the case of small-sized shallow-bottomed utensils, there is a drawback in that the hardening of the bottom surface is insufficient, and it has been considered impossible to manufacture thin-walled, shallow-bottomed fluororesin-coated aluminum utensils that are difficult to deform. In order to provide a solution to the above-mentioned problems, the inventors of the present invention have conducted various research studies, and as a result, they have developed a method using a specific aluminum-based metal base material and a specific fluorine-based resin coating. By adopting a method in which molding is carried out under the following conditions and then press molding is performed, we have come to the surprising finding that it is possible to manufacture fluorine-based resin-coated aluminum utensils that are resistant to deformation and have a thin wall and a shallow bottom.

Thus, the present invention has been completed based on the above findings, and a fluorocarbon resin is applied to a work-hardened thin aluminum metal base material with a yield strength of 10 kg/ml or more at a temperature of 34°C.
To provide a new method for manufacturing fluorine-based resin-coated aluminum utensils, which comprises coating under baking conditions of 0°C or less for 30 minutes or less, and then press-molding into a shallow-bottomed utensil shape. It is. According to the method of the present invention, it is possible to manufacture thin-walled, shallow-bottomed fluorine-based resin-coated aluminum utensils that are difficult to deform. By using meat, for example, when the present invention is applied to the production of ice trays, a product with high ice production efficiency can be obtained, and in the case of lunch boxes, weight reduction can be achieved, increasing the commercial value. Various advantages are exhibited.

In the method of the present invention, it is important to use an aluminum-based metal base material that has a work-hardened yield strength of 10 kg/i or more, preferably 12 kg/md or more.

)・Aluminum-based metal base material ｝i2=? 2γ
■If it has the resistance of Pjima゜hki, it is t gold, ``Nako hard 4
5 (JISH4000-1976 temper code: Hin; however, n = 4 to 6, the same applies hereafter), those that have been moderately annealed after work hardening (H2n), and those that are stable after work hardening. (H3n) can be applied, and in terms of materials, pure aluminum with a purity of 99.0% or more, aluminum alloys such as duralumin (
Furthermore, materials containing small amounts of manganese, magnesium, copper, etc. are exemplified, but in terms of formability etc., 1100 material,
3003 material, 3004 material, 5005 material, etc. can be preferably employed.

When using a soft aluminum-based metal base material with a yield strength of 10 kg/i or less, the base material will be further softened due to heat history when coated with fluorine-based resin, especially for shallow-bottomed vessels. However, due to the small amount of processing deformation during molding into a container shape, a product with low yield strength can only be obtained.
In order to suppress deformation during use of utensils, the thickness of the base material must be increased. In the method of the present invention, it is also important to perform baking under relatively mild conditions during coating with fluorine resin, and the heating conditions include a temperature of 340°C or less,
Time 30 minutes or less, preferably temperature 330℃ or less, time 1
A time of 0 minutes or less will be adopted.

Fluorine-based resins that can be coated under such heating conditions include:
For example, ethylene-tetrafluoroethylene copolymer, ethylene-chlorotrifluoroethylene copolymer,
Examples include melt-moldable fluororesins such as tetrafluoroethylene-hexafluoropropene copolymer, tetrafluoroethylene-perfluorovinyl ether copolymer, vinylidene fluoride polymer, and vinyl fluoride polymer. However, it does not include polytetrafluoroethylene, which has traditionally been widely used in the production of fluorine-based resin-coated aluminum utensils. Therefore, as a fluororesin that can be melt-molded,
The volumetric flow rate defined below is from 10 to 300 mm3/sec, preferably from 25 to 160 Tm3/sec.
As used herein, the term "volume flow rate" is defined as follows. That is, using a Koka type flow tester, 1 g from a nozzle with a nozzle diameter of 1 mm and a land length of 2 mm under a specified temperature and a specified load of 30 kg/a01.
The value expressed by the volume of the molten sample extruded per unit time is defined as the "volume flow rate", and its unit is WI, 3/sec. Here, the predetermined temperature is a temperature within the temperature range (temperature range between the flow start temperature and thermal decomposition start temperature) in which the specific fluororesin can be melt-molded and close to the flow start temperature. . Suitable fluororesins in the present invention include ethylene-tetrafluoroethylene copolymers and ethylene-chlorotrifluoroethylene copolymers.

That is, the molar ratio of tetrafluoroethylene (or chlorotrifluoroethylene)/ethylene is 40/6.
0 to about 70/30, especially about 45/55 to 60/40, and the volume flow rate is 10 to 300 mm3/sec, especially 25
A speed of about 160 mm3/sec is particularly suitable. mosquito·
A suitable ethylene-tetrafluoroethylene copolymer has a flow start temperature of about 260 to 300°C and a thermal decomposition start temperature of about 320 to 360°C. Further, a suitable ethylene-chlorotrifluoroethylene copolymer has a flow start temperature of about 220 to 260°C and a thermal decomposition start temperature of about 300 to 340°C. The preferred ethylene-tetrafluoroethylene (or chlorotrifluoroethylene) copolymer contains, in addition to ethylene and tetrafluoroethylene (or chlortrifluoroethylene), small amounts of comonomers (propylene, isoptylene, vinyl fluoride, vinylidene fluoride, hexafluoropropene, acrylic acid and acrylic esters, vinyl acetate, perfluoroalkyl vinyl ether, hexafluoroisoptylene, perfluoroalkyl ethylene, etc.) or modifiers. But that's fine. In the present invention, the aluminum-based metal substrate can be coated with the fluorine-based resin by various methods, such as applying a powder or aqueous or organic dispersion of the resin and firing it, or melt-pressing a film of the resin. However, in industrial implementation, electrostatic powder coating is preferably employed from the viewpoints of mass productivity, pollution control, resin yield, etc.

By the way, in coatings made of melt-formable fluororesin, it is generally observed that the adhesion strength tends to decrease as baking conditions become milder, and it is desirable to take this point into consideration when applying the method of the present invention. .

That is, an aluminum metal base material that has been previously treated by electrolytic etching or immersion in a sulfuric acid/hydrogen peroxide solution is used to improve the adhesion strength. It is a preferable aspect to aim for improvement. The method of the present invention is applied to the production of shallow-bottomed fluorine-based resin-coated aluminum utensils, and exhibits the effect of producing thin-walled utensils that are difficult to deform.
This method is useful as a method for manufacturing objects smaller than mm in size.

Kakaru shallow-bottomed utensils include ice cube trays, lunch boxes, butts,
Ashtray, cake mold, pudding cup, frying pan, two-handed pot,
Various products such as a one-handed pot are exemplified, but it is particularly useful for applications that are susceptible to external force during use, such as a method for manufacturing ice trays, lunch boxes, and the like.

Next, embodiments of the present invention will be explained in more detail, but it goes without saying that the present invention is not limited by such explanations, and as appropriate as long as it does not depart from the purpose and spirit of the present invention. It is possible to add or change. Example 1 Ethylene was used as a coating material with a molar ratio of tetrafluoroethylene/ethylene of 53/47, a flow start temperature of 280°C, a thermal decomposition start temperature of 350°C, and a volumetric flow rate of 90 mm3/sec at 300°C. A powder of tetrafluoroethylene copolymer with an average particle size of 20 microns is used.

Purity 99 with a thickness of 1 mm work hardened by roll rolling
．． The base material is a 0% aluminum plate (AllOOP-Hl8: yield strength 15.5 kg/Mit) that has been previously sandblasted and then electrolytically etched.

The copolymer powder was sprayed onto the base material using an electrostatic powder coater and baked at 320° C. for 3 minutes to obtain a fluororesin-coated plate. In addition, the baking temperature was measured by bringing a thermocouple into close contact with the back surface of the base material. Using the thus obtained coated plate, press molding into a size of 60 mm x 160 mm depth 3
A 0 mm square container was manufactured.

The yield strength of the bottom surface of the vessel was 12.0 kg/Mlt, which was found to be a sufficiently large value. The yield strength of the coated plate before pressing was 9.0 kg/M7i. Comparative Example 1 A vessel was manufactured in the same manner as in Example 1, except that a sufficiently annealed board (AllOOP-0 yield strength 2.8 kg/Md) was used as the base material.

The utensil is easily deformed by external force, and the yield strength of the bottom is 3.5
It was only kg/Mi. Comparative Example 2 A vessel was manufactured in the same manner as in Example 1, except that an aqueous dispersion of polytetrafluoroethylene was used as the coating material and baking was performed at 360° C. for 10 minutes.

The utensil is also easily deformed by external force, and the yield strength of the bottom is 5.1.
kg/ml. In this case, the yield strength of the covering plate was reduced to 3.0 kg/Mlt. Example 2 A powder of tetrafluoroethylene-perfluorovinyl ether copolymer (average particle size: 35 microns: Teflon 8PFAMP-10 manufactured by Mitsui Fluorochemical Co., Ltd.) was used as a coating material, and baking was performed at 330° for 10 minutes. A vessel was manufactured in the same manner as in Example 1 except for this.

The bottom surface of the vessel had a yield strength of 9.2 kg/M7fL. The yield strength of the covering plate before pressing is 6.0 kg/Md.
It was hot. Comparative Example 3 In the example, when baking was performed at 360°C for 10 minutes, the yield strength of the covering plate decreased to 3.1 kg/Mi, and the yield strength of the bottom of the utensil after pressing was also 5.0 kg/1! It was nothing more than an i.

Example 3 The molar ratio of chlorotrifluoroethylene/ethylene as the coating material was 50/50, and the flow start temperature was 230°C.
, an ethylene-chlorotrifluoroethylene copolymer with a thermal decomposition initiation temperature of 300°C and a volumetric flow rate of 100 [Nnl3/sec at 275°C] was used, and baking was carried out at 270°C.
A utensil was manufactured in the same manner as in Example 1, except that the heating was carried out for 5 minutes.

The bottom surface of the vessel had a durability of 13.0 kg/i. Example 4 1.25% manganese and 1.25% magnesium as base materials.
A utensil was manufactured in the same manner as in Example 1, except that a rolled plate of aluminum alloy containing 30% of thickness 1NIn (yield strength 25.0 kg/i) was used and baking was performed at 320° C. for 5 minutes.

The bottom surface of the vessel had a yield strength of 17.0 kg/Mit. Comparative Example 4 When the same base material as in Example 4 was used, and the covering material and baking conditions were the same as in Comparative Example 2, the yield strength of the bottom surface of the resulting utensil was only 8.0 kg/Md.

Claims (1)

[Claims] 1. A fluorine-based resin is applied to a work-hardened thin aluminum-based metal base material with a yield strength of 10 kg/mm^2 or more at a temperature of 34°C.
1. A method for producing fluororesin-coated aluminum utensils, which comprises coating under baking conditions of 0° C. or lower for 30 minutes or less, and then press-molding into a shallow-bottomed utensil shape. 2. The method of manufacturing a vessel according to claim 1, wherein a flat plate-like material with a thickness of 0.5 to 1.8 mm that has been work-hardened by roll rolling is used as the aluminum-based metal base material. 3. The method for manufacturing a vessel according to claim 1, wherein a fluororesin having a volumetric flow rate of 10 to 300 mm^3/sec as defined herein is used. 4. Manufacturing of the vessel according to claim 3, using an ethylene-tetrafluoroethylene copolymer having a molar ratio of tetrafluoroethylene/ethylene of 40/60 to 70/30 as the fluororesin. Method. 5. Manufacturing of the vessel according to claim 3, using an ethylene-chlorotrifluoroethylene copolymer having a molar ratio of chlorotrifluoroethylene/ethylene of 40/60 to 70/30 as the fluororesin. Method. 6. The method of manufacturing a vessel according to claim 1, wherein the fluororesin coating is performed by an electrostatic powder coating method. 7. The method of manufacturing a vessel according to claim 1, which uses an aluminum metal that has been previously treated to improve adhesion prior to being coated with a fluororesin. 8. The method for manufacturing a container according to claim 1, wherein the container is an ice tray. 9. The method for manufacturing a utensil according to claim 1, wherein the utensil is a lunch box.