JPH0373337A - Film and laminated material for easy can opening - Google Patents

Abstract

PURPOSE:To prevent crack due to the shock at working and the consequent corrosion of metal plate from occurring by a method wherein film, which is made of biaxially stretched polyester resin and the density, plane orientation coefficient and melting point of which are specified, is used in laminated material. CONSTITUTION:Polyester resin used for film is condensation polymer of dicarboxylic acid and diol and the typical polyester resin is polyethylene terephthalate resin. Said polyester resin is formed into the shape of film and, after that, biaxially stretched. The density of the film is 1.365-1.395g/cm<3>, its plane orientation coefficient is 0.070-0.135 and its melting point is 210 deg.C or higher. For the manufacture of laminated material 20, for example, the film 24, on the surface of which adhesive 23 is applied, and a metal plate 21, on both sides of which chromate treatments 22A and 22B are applied, are piled up so a to be fused together by heating. Further, on the surface of the laminated material, printing layer 25, onto which the name of commodity is shown, is provided. Finally, the laminated material is formed into an easy open can having the desired form by means of press molding or the like.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention provides a film J and a laminate material, a film J used for a laminate material for 1↑・f-G-oven cans, and a film L thereof. Prepared 41iFf! Regarding i-materials.

[Conventional technology]

Easy to open without using special equipment such as f1i cutter
The so-called Easy Maven Street is widely used for canned foods.

The vertical cross section of the pipe H used in such an f-G oven is not shown in Fig. 4, and the f5 material 1 is composed of +, ζ, metal plate 2, fill J, and l 4. .

On the front surface (J- side in drawing Q) and the back surface (F(11) in the drawing) of gold S tentative 11, a lithium mate treatment layer 128, +211 °C is formed. The chromate treatment layer 128 on the front side is provided with a printing 115 for displaying the product name of the can. There is C.

As the film 1.14, a polyester film J which is oriented and crystallized by biaxial stretching and which has 11 fJ strength and heat resistance is used. ).

[Problem to be solved by the invention]

In order to construct the °ζ easy open flj using such ff14'1, score machining to demarcate the part to be opened and rivet machining to attach the handle to the flj material! It is necessary to apply For example, in score processing, as shown in FIG. 4, score 5 is provided to the inside of the metal plate: the mold.

These additions [especially 11i9, soil l,
14 may cause cracks. Particularly when deep score processing is performed, cracks are likely to occur. This filter]
The cracks that occur in No. 4 cause corrosion of the (tit) amount.

The purpose of the first invention is to create a filter for easy open frI that is less likely to crack due to impact during machining.
There is something for every thing you do.

The purpose of the second invention is to perform one foot iR of the lamination assembly 4 using the film for easy open fli according to the first invention.

(XV. Means for Solving the Problem) The film according to the single-port invention is a film used as a top layer material for easy-open cans. This film is made of a biaxially stretched polyester resin. And the density is 1.365.~l.

395, a plane orientation coefficient of 0.070 to 0.135, and a melting point of 210°C or higher.

The polyester resin used in the film of the present invention is a wi-articulate complex of dicarboxylic acid and diol. Examples of dicarboxylic acids include aromatic and Examples include aliphatic dicarboxylic acids.

These dicarboxylic acids may be used alone or
211 or more may be used as a mixture, and the diols include ethylene glycol, butanediol, hexanediol, neopentyl glycol, cyclohexane dimethanol, decanediol, Schiff 11hexanediol, 2-ethyl-2-butyl Examples include -1 to butt3 pandiol. These diols are
It may be used alone or in a mixture of two or more types. Polyester m1M may also be co-used with other monomers or polymers such as diethylene glycol, triethylene glycol, or polyethylene glycol. A typical polyester resin used in the present invention may be a polyethylene terephthalate resin.

The film of the present invention is obtained by molding the polyester resin into a film shape and stretching it biaxially. The stretching ratio is 3°3 or less in both the longitudinal and transverse directions, and 3.
The thickness of the film is preferably 6 to 1
0 Gpm is desirable.

In particular, it is desirable to have an I[1lFI of 12 to 50 m from the viewpoint of both corrosion resistance and ease of opening.

The density of the film of the present invention is 1.365 to 1°395g
/cj. Furthermore, 1.370~1゜390g/c
If the density is less than 1.365, where d is desirable, the crystallization of the film will be insufficient and the amount of gas permeation will increase. As a result, the amount of water vapor permeation increases and rust occurs on the easy open fTi.

In addition, the heat shrinkage rate becomes high, and heat loss may occur when laminating with a metal plate. On the other hand, if the density exceeds 1.395, the crystallization of the fill 11 slows down, so that the difference in physical properties between the direction of the orientation axis of the fill 1 and the direction orthogonal thereto increases. In particular, the difference in elongation and thermal contraction becomes large.

The density was determined by creating a °ζ density gradient tube using a mixture of carbon tetrachloride and n-heptane, and adding sample t1 to it.
This is the measured value. Note that the measurement temperature was 25°C.

The plane orientation coefficient of the film of the present invention is 0.070 to 0.1
It is 35. Furthermore, 0.080 to 0°130 is preferable, and if the plane orientation coefficient is 0.07 (1-#), the fill J may not be cut according to the scoring process when opening the can.
The film may protrude into the opening of the can. On the other hand, if the plane orientation coefficient is greater than 0.135, the film is likely to crack during scoring or riveting.

Note that the plane orientation coefficient ("p") is a value calculated using the following formula.

rP=(n++-nm)/2-nj where, nl; refractive index in the vertical direction n, : refractive index in the horizontal direction n3 = refractive index in the thickness direction. Also, the refractive index is the tangent WfI of the Atsube refractometer. (A polarizing plate analyzer was attached to the yll, and the measurement was carried out using single-light color NaD&fl. The mounting liquid used monomerized methylene, and the measurement was carried out at 25°C.

The melting point of the film of the present invention is 210°C or higher, preferably 210°C or higher.
The temperature is 15°C or higher. If the melting point is less than 210℃, keep it at a high temperature on the outside of the easy-open can! l! f! When a film or a printed layer is provided, the film may become deformed or whitened.

The melting point of the film was measured using a differential calorimeter (DSC).
This is the value measured using The measurement was performed using a sample log at a heating temperature of 10° C./min, and the peak temperature when the sample t't melted was taken as the melting point.

Next, the method for manufacturing the film 1 of the present invention will be explained.

First, a polyester film is produced from the polyester IM resin described above using a well-known r'-stage such as roll casting. Fringe absorbent, plasticizer, inorganic particles, laminated lubricant, pn tit.

The 1r# polyester film J, which may be dispersed and blended with antistatic +L additives, is stretched in the II axis direction and the transverse axis direction to form a coaxially stretched polyester film. Then, biaxially stretched Bolier six tersoirno,
At t, heat treatment is performed. Heat) 31 temperature is 160~
240"C2, preferably 170 to 220"C.If the heat treatment temperature is less than 160"C, the crystallization of the polyester film will be insufficient and a film with the desired density will not be obtained.On the contrary, Heat treatment temperature is 240°C
If it exceeds this temperature, the polyester film J will melt. Note that the heat treatment temperature can be appropriately selected according to the type of polyester resin and the stretching conditions of the film I.

*** Matters *** The laminated material according to the second invention is a laminated material used for easy-open cans. This 4R layer material includes a metal plate and the easy-open trust film according to the first invention laminated on the metal plate.

An example of the laminated material according to the present invention is shown in FIG.

Gold [Fi2j is made of commonly used canning metals such as tin, aluminum Uno 1, and steel. The thickness of the metal plate 21 is generally 0.20 to 0.20. ri01111, further 0.
23 to 0.30- or preferably, the thickness of the metal plate is
It is selected as appropriate depending on the parts of the can such as the lid and the can body.

Chromate treatment M228, 22B is formed on the surface (top of the drawing) and the back surface (bottom 1ll of the drawing) of the gold fiFi 21. Chromate treatment layer 22A.

22R is for improving the corrosion resistance of the metal plate 21. Chromate treatment M22A, 22■ is performed by adding gold rI! to a treatment solution consisting of, for example, CrOs, HsP04, F, and water. It is formed by dipping the temporary 21 in the water. In addition, chromate treatment *22A.

22I3 is 0, 5~5, 077rn
degree is desirable.

The film 24 is laminated on the chromate-treated WI22N3 coated on the back surface of the metal plate 21 via the adhesive layer 23.The film 24 is made of polyester resin stretched in the direction of the two wheels according to the first invention. For the adhesive layer 23, an adhesive made of, for example, epoxy resin and phenol resin is used.

Chromate treatment layer 22 applied to the surface of metal Fi, 21
8. For example, printing Nl for displaying the product name. 5
is provided.

The method of manufacturing such a laminated material 20 is, for example, by applying an adhesive to the surface of the film 24 and then applying the adhesive to the surface of the film 24.
, 24 and a chromate-treated metal plate 21 are overlapped and fused under heating.

The laminated material of the present invention is formed into an easy-open can of a desired shape, such as for beverages or corned beef cans, by means such as press molding.

Examples of can lids manufactured using the laminate of the present invention are shown in FIGS. 2 and 3. FIG. 2 shows the top surface of the can IEIO. In addition, FIG. 3 shows the mm-m cross section of FIG.
There is.

The can M10 includes an annular rim 2 near the same edge that is fitted inside the side surface of the can body. The outer circumferential side of rim 2 is dense.
1 river groove 3 is formed, where the fli trunk and <rt
It is lined with a sealant 16 for sealing with Mlo. A score 5 is provided on the inside of the rim 2 to define a portion 4 to be opened. A rivet 6 is formed in the portion 4 to be opened 11, and the rivet 6
is protruding from the surface iif@ of the can lid. The rIr1 sealing pull tab 7 has an Un sealing point 8 at one end. The opening pull tab 7 is fixed to the portion 4 to be opened by fixing the opening fulcrum 8 to the rivet 6.

The above 151110 is the unsealing pull tab 7 and the unsealing fulcrum 8
Stand upward using the fulcrum, and then pull the opening pull tab 7.
The bag is opened by pulling L1 in the 4 directions to open it.

In the fliliO, the score 5 is formed by score processing. Further, the opening pull tab 7 is fixed with rivets. During these processes, film 2
4 is shocked. However, since the film 24 is made of the polyester film 1 according to the first aspect of the invention, it does not easily crack even when subjected to impact, and therefore the metal plate 21 can be prevented from being exposed and corroded.

〔Example〕

ILI 15 mol% of repeating 11th position of ethylene isophthalate
The polyethylene terephthalate-isofucrete copolymer contained therein was melted at a temperature of 280°C and formed into a sheet using a casting drum at 20°C to obtain a 4MJ1M film. The obtained resin film was heated at 90°C in the longitudinal direction 3.
After stretching 3.0 times in the transverse direction at 105°C, 2()
A biaxially stretched film 11 having a thickness of 25 It m was obtained by heat treatment at 0°C.

On one side of the obtained biaxially stretched film, a mixture of Seiryoku Bond E295 and C-26 (manufactured by Tenchi TN Kakogyo N) was applied as an S-contacting agent at a rate of 3.0 g/rd tjJ in a dry state. Then, a thickness of 0.28 m was applied to the contact surface of the film.
The aluminum plate was rolled at a roll temperature of 60°C to obtain a laminate. The resulting laminate has a score of 90
The score was processed so that it became 〃m.

- Biaxial polyester resin using ethylene glycol containing ζterephthalic acid as a dicarboxylic acid and 3 mol% of 1,4-cyclobenzene dimethanol as a diol component in the same manner as in Example 1. A stretched film was obtained.

The obtained two-wheel stretched film was heat-treated at 205° C. to obtain a two-wheel stretched film having a thickness of 25 pm.

f in the same manner as in Example I using the obtained two-wheel stretched film.
JI layer material was made and scored.

A 74M resin film was obtained in the same manner as in Example 1 from polyethylene terephthalate 4II 4 resin using dicarboxylic acid (terephthalic acid) and 11 coals as the diol component. IJJlj?Phil J,
2.6 times in the vertical direction at 105°C, 2.6 times in the horizontal direction at 130°C.
After stretching for 6 inches, it was heat-treated at 225°C to obtain a biaxially stretched film with a thickness of 20 pm.

Using the obtained biaxially stretched film, a laminate was prepared in the same manner as in Example 1, and score processing was performed.

Jt-Comparison, □□□11, A polyethylene terephthalate-isophthalate copolymer containing 22 mol% of repeating units of ethylene isophthalate was melted at a temperature of 280°C, and a resin film 1 was obtained in the same manner as in Example 1. Ta. The obtained resin film was heated to 90°C.
The film was stretched 3.3 (Δ, 3.0 times in the transverse direction at 105°C in the machine direction) and heat-treated at 185°C to obtain a biaxially stretched film 1 with a length of 30 m.

Using the obtained biaxially stretched film, an H# layer material was prepared in the same manner as in Example 1, and score processing was performed.

1t-1? lL2- Repeating unit of 1-f-lene isophthalate (1″i,
An MJ resin film was prepared in the same manner as in Example 1 from a polyethylene terephthalate-isophthalate copolymer containing 3 mol% of The obtained resin film was stretched 3.5 times in the vertical direction at 95°C and 3.3 times in the horizontal direction at 110°C.
Heat treated at 225℃, thickness 251! A biaxially stretched film of m was obtained.

Using the obtained biaxially stretched film, a laminate t4 was prepared in the same manner as in Example 1, and score pressure was applied.

Jt comparison? L-1 The castor paste obtained in Example 1 was heated at 95'C in the longitudinal direction.
After stretching for 4.11 m in the direction, a biaxially stretched film J having a thickness of 20 B m was obtained.

A laminate was prepared in the same manner as in Example 1 using the obtained biaxially stretched film J, and subjected to S:lA addition.

Comparison - Shio 14-Example 3 (Similar resin fill J, 110
'C: 3.6x vertically, 1301x horizontally: 3.
After stretching to 7 (n), heat treatment was performed at 230° to obtain a uniaxially stretched film having a thickness of 17 2Q//m.

A laminated material was prepared in the same manner as in Example 1 using the obtained uniaxially stretched material, and subjected to the Suni 17 processing.

'912 5 dicarboxylic acid, monozeta terephthalic acid, di:4-J component and L7 with 30 mol% 1,4-Schiff 11 hex 1J:'
A polyester resin using ethylene glycol containing fumethanol was melted at a temperature of 270°C to obtain L'ζ (4-fatty fluorine) in the same manner as in Example 1. , 2.8 times vertically at 90°C, 105°C
After stretching 2.8 times in the transverse direction with
, obtained.

Using the obtained axially stretched film J, a laminated film was prepared in the same manner as in Example I, and pressure was applied to the film J7. Ta.

Comparative Example-6 Terephthalic acid containing 20 mol% adipic acid as a dicarboxylic acid, diol component: L-
A ζ resin film was obtained in the same manner as in Example 1 from a polyester resin using a polyester resin. The obtained resin fill J is 90
'C'? ? After stretching 3.1 times in the longitudinal direction and 3.1 times in the transverse force direction at [05°
A biaxially stretched film 1 of 0 μm was obtained.

Using the obtained -uniaxially stretched film, a laminate was prepared in the same manner as in Example 1 and subjected to score processing.

The density, planar orientation coefficient, and melting point of the uniaxially stretched soil films used in Ku-guo Examples G41-3 and Comparative Examples 1-6 were investigated.

In addition, the heat resistance of the laminated material and the fill J
, we investigated the wear and tear of the . In addition, the heat resistance and cracking were determined by the C31 valence as follows.

The small J1 of the 17M laminate was placed in a dry heat oven at 210'C for 5 minutes, and the condition of the fill J was visually observed. ! The f value is as follows.

○: No change.

×: Whitening occurs.

Another car: t°? We conducted 11 autumn trials of energizing the laminate material to which we applied the heat, and determined that the film cracked in the energized pigeon coop. What? , J¥ salt water was used as the electrolyte.

The evaluation is as follows.

O: No cracks.

×: There are cracks.

Table 1 [Effects of the invention] In the first invention, the score is added 1:? It is possible to obtain fill J for easy-open cans that is difficult to separate due to the impact of J rivet processing.

In the second invention, since the easy-open film J according to the first invention is used, the film is less likely to crack even when subjected to scoring or riveting.

Therefore, corrosion of metal plates can be avoided.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional partial view of a laminated material according to an example of the second invention, FIG. 2 is a plan view of an easy-open can, and FIG.
The III-III sectional view in the figure, Figure 4 shows the conventional laminated material $
1# side view. 20... Laminated material, 21... Metal plate, 24... Film.

Claims (2)

[Claims] (1) A film used for laminated materials for easy-open cans, made of biaxially stretched polyester resin, with a density of 1.365 to 1.395 and a plane orientation coefficient of 0.07.
0 to 0.135 and a melting point of 210°C or higher, a film for easy-open cans. (2) A laminate material used for easy-open cans, comprising: a metal plate; and the easy-open can film according to claim 1, which is laminated on the metal plate.