JP4590886B2 - Multi-layer film for laminating, laminating material, can resistance and can lid - Google Patents

Description

  The present invention relates to a multilayer film formed by laminating a polyester resin and a laminate material formed by coating the multilayer film. More specifically, the multilayer film and a metal plate can be laminated at high speed, and excellent thickness uniformity is provided. The present invention also relates to a multilayer film that can be coated on a metal plate with adhesiveness and a laminate material excellent in processability formed by coating the multilayer film.

  Conventionally, as a means for imparting corrosion resistance to a metal material, it is widely performed to coat a metal surface with a resin layer, and as a coating method used in such a technique, an epoxy resin, a phenol resin, an acrylic resin, A method in which a thermosetting resin such as a polyester resin is dispersed in a solvent is applied to a metal surface, or a pre-formed film, for example, a polyester, olefin, or polyamide film is an isocyanate, epoxy, A method of bonding to a metal substrate via a phenol-based adhesive or the like is known.

  It is also widely known that the heat-fusibility of a thermoplastic resin is used for bonding a metal substrate and a thermoplastic resin. In this method, a preformed film such as a thermoplastic polyester resin is applied to a metal plate. There are known a method of bonding by thermal bonding and a method of bonding a molten thin film such as an extruded thermoplastic polyester resin to a metal plate.

The latter method of bonding to a metal plate by the extrusion laminating method is advantageous in that it can process at a very high speed and can reduce the work involved in film formation and the cost for it.
As the extrusion laminating method, a T-die method using an extruder and a T-die is generally adopted. However, in such a T-die method, unstable flow inside the extruder and the die, or between the T-die and the metal plate. Since there is a slight air gap between them, when general polyester is used, film sway, pulsation, etc. occur, and a stable and uniform coating layer can be formed on the metal plate with good adhesion. It is difficult to form. These phenomena are particularly likely to occur when the resin take-up speed is increased, making high-speed lamination of the polyester resin very difficult.

Various proposals have been made to solve the above-described problems. For example, the applicant of the present invention has a melt viscosity ratio at a temperature during melt extrusion (melt viscosity η at a shear rate of 12.2 sec ⁻¹ at the extrusion temperature of polyester). _12.2 / The melt viscosity η ₁₂₁₆ at a shear rate of ₁₂₁₆ sec ⁻¹ at the extrusion temperature of polyester is 2.0 or more and η ₁₂₁₆ is 500 poise or more, and the resin layer is melt-extruded and then rapidly cooled. A laminate characterized by the fact that an ethylene oxide adduct of bisphenol or a polyester resin containing a tribasic or higher polybasic acid and a polyhydric alcohol is used. Describes that a coating with excellent uniformity and adhesion can be obtained. That (Patent Document 1).

  Further, a polyester mainly composed of ethylene terephthalate containing 0.1 to 2.0 mol% of a compound having 3 or 4 ester bond-forming functional groups, and having a melting point of 220 ° C. or higher, the melting point of the polyester + 40 ° C. It is described that a polyester having a die swell measured at a temperature of 1.3 or more is excellent in extrusion processability (Patent Document 2).

JP 10-86308 A JP 2001-72747 A

However, since polyesters containing polyfunctional components have monomers and oligomers remaining, there is a problem of flavor properties due to elution of such components. Even in the latter polyesters described above, such monomers and oligomers are also present. In order to reduce this, it is necessary to perform a certain treatment on the polyester.
Therefore, the object of the present invention is that even when laminated on a metal plate by a high-speed extrusion laminating method, it is possible to coat the metal plate with a uniform film thickness and good adhesion without causing the above-mentioned film shaking and pulsation. Providing a multilayer film.
Another object of the present invention is to provide a laminate material in which elution of low molecular weight components in polyester is prevented, the flavor property is excellent, and the uniformity and adhesion of the coating layer are excellent.

According to the present invention, there is provided an ethylene terephthalate polyester resin comprising a tribasic or higher polybasic acid or polyhydric alcohol in an amount of 0.01 to 0.50 mol% and isophthalic acid in an amount of 10 to 20 mol%. Te, the first polyester resin is in the range melt tension of 50 to 212mN in 240 ° C., a multilayer film Ru formed by laminating other second polyester resin, said first polyester resin wherein the the ratio of the melt tension of the melt tension of one polyester resin and a second larger than the melt tension of the polyester resin and the first polyester resin second polyester resin is 1.1: Ru 1 der: 1 to 5 A multilayer film is provided.
In this multilayer film, the thickness ratio of the first polyester resin to the second polyester resin is preferably 50: 1 to 1: 5.
According to the present invention, there are also provided a laminate material obtained by laminating the multilayer film on a metal body, and a can body and a can lid made of the laminate material.

  According to the multilayer film for laminate of the present invention, the second polyester resin is added to the first polyester resin containing 0.01 to 0.50 mol% of the polyfunctional component and having a melt tension of 50 mN or more. By laminating, it is possible to effectively prevent the occurrence of film shaking and pulsation even when extruded and laminated on a metal substrate at a high speed, and it has excellent uniformity and adhesion of the coating layer as well as flavor. Laminate material can be provided.

In the present invention, in a multilayer film for laminating for laminating on a metal plate, the first polyester resin containing 0.01 to 0.50 mol% of a polyfunctional component and having a melt tension of 50 mN or more, By laminating two polyester resins, even when laminating to a metal substrate at high speed, film shaking and pulsation can be prevented, and a multilayer film having a uniform film thickness can be supplied to the metal substrate. is there.
That is, since a general polyester resin (polyethylene terephthalate) has a low melt tension and melt viscosity, when extruded and laminated to a metal substrate at a high speed, a phenomenon of film shaking in which the end in the width direction of the molten resin film coming out of the T-die is shaken, A phenomenon called pulsation occurs in which the molten resin film coming out of the T-die has uneven thickness in the longitudinal direction. For this reason, a uniform film thickness cannot be obtained, and adhesion to the metal substrate is also lowered. On the other hand, an increase in melt tension is accompanied by a marked increase in viscosity, so that ordinary extruders are inferior in extrudability and cannot be extruded at high speed.

In the present invention, from such a viewpoint, when the polyester resin contains 0.01 to 0.50 mol% of the polyfunctional component, the polyfunctional component is introduced into the polyester main chain, so that the branched chain or the crosslinked chain is introduced. After the extrusion from the die without excessively increasing the melt viscosity in the extruder, it is possible to increase the melt tension, especially when the melt tension is set to 50 mN or more, even by extrusion lamination at high speed. It effectively prevents pulsation.
Such operational effects of the present invention are also apparent from the results of Examples described later. That is, a polyester resin that does not contain a polyfunctional component and has a melt tension of less than 50 mN (Comparative Example 1), or a polyester resin that contains a polyfunctional component in an amount within the above range but has a melt tension of less than 50 mN. In (Comparative Example 2), when the film was extruded at a speed of 100 m / min, the film swayed, whereas the polyfunctional component was contained in the above range, and the melt tension was 50 mN or more. The polyester resin has no film shaking or pulsation (Examples 1 to 4), the polyester resin contains 0.01 to 0.50 mol% of a polyfunctional component, and the melt tension is 50 mN or more. It is understood that excellent high-speed extrusion laminating properties are expressed.

On the other hand, since the polyester resin containing such a polyfunctional component has a high polymerization rate, monomers and oligomers are likely to remain, and there is a problem of flavor properties due to the elution of such low molecular weight components. By laminating the second polyester resin that does not contain such low molecular weight components on the first polyester resin layer, it is possible to prevent a decrease in flavor due to elution of low molecular weight components from the first polyester resin layer It becomes.
That is, the first polyester resin improves the extrusion laminating property of the multilayer film at a high speed, and the use of the second polyester resin layer can prevent a decrease in flavor due to the use of the first polyester resin. Therefore, it is possible to provide a multilayer film having all the characteristics as the entire multilayer film.

  In the present invention, the melt tension of the first polyester resin is preferably larger than the melt tension of the second polyester resin. That is, the first polyester resin can have a melt tension of 50 mN or more without increasing the melt viscosity in the extruder due to the presence of the polyfunctional component. Since there is a correlation with the melt viscosity, if the melt tension is increased, the melt viscosity becomes too high, and an excessive load is applied to the extruder, which may make extrusion impossible.

In the present invention, in particular, the ratio of the melt tension of the first polyester resin and the second polyester resin is in the range of 1.1: 1 to 5: 1, particularly 1.5: 1 to 3: 1. Is preferred. That is, when the difference in melt tension between the first polyester resin and the second polyester resin is large and the ratio is larger than the above range, pulsation may occur in extrusion lamination at high speed. On the other hand, when the ratio is smaller than the above range, the melt viscosity of the second polyester resin becomes too high, and as described above, an excessive burden is imposed on the extruder and extrusion may be impossible.
The thickness ratio of the first polyester resin to the second polyester resin is preferably in the range of 50: 1 to 1: 5, particularly 10: 1 to 1: 1. When the thickness ratio is within the above range, both high-speed extrusion laminating properties and flavor properties can be provided in a balanced manner.

In the laminate material of the present invention, the multilayer film is laminated on a metal substrate, and it is important in terms of flavor properties that the first polyester resin layer is laminated on the metal substrate side. When not used on the inner surface side of a container or the like, the present invention is not limited to this, and the first polyester resin layer can be laminated as a surface layer.
In FIG. 1 showing an example of a cross-sectional structure of a laminate material in which the multilayer film of the present invention is laminated on a metal substrate, the laminate material 1 includes a metal substrate 2, a first polyester resin layer 3 positioned on the metal substrate side, It consists of a second polyester resin layer 4 formed on one polyester resin layer.
In FIG. 2 which shows the other example of the cross-sectional structure of a laminate material, it is a figure except the 1st polyester resin layer 5 and the 2nd polyester resin layer 6 being formed also in the outer surface side in the laminate material shown in FIG. Same as 1.
FIG. 3 is the same as FIG. 1 except that the adhesive resin layer 7 is provided between the first polyester resin layer 3 and the metal substrate 2 in the laminate shown in FIG.

(First polyester resin)
The first polyester resin used in the present invention comprises a conventionally known dicarboxylic acid component and a diol component except that it contains 0.01 to 0.50 mol% of a polyfunctional component and has a melt tension of 50 mN or more. A polyester resin can be used.

  As the dicarboxylic acid component, 50% or more, particularly 80% or more of the dicarboxylic acid component is preferably terephthalic acid from the mechanical properties and thermal properties of the coating layer. Carboxylic acid components other than terephthalic acid, that is, copolymer components As isophthalic acid, naphthalenedicarboxylic acid, p-β-oxyethoxybenzoic acid, biphenyl-4,4′-dicarboxylic acid, diphenoxyethane-4,4′-dicarboxylic acid, 5-sodium sulfoisophthalic acid, hexahydro Examples include terephthalic acid, adipic acid, and sebacic acid.

  As the diol component, it is preferable from the mechanical properties and thermal properties of the coating layer that 50% or more, particularly 80% or more of the diol component is ethylene glycol. As the diol component other than ethylene glycol, 1,4- Examples include butanediol, propylene glycol, neopentyl glycol, 1,6-hexylene glycol, diethylene glycol, triethylene glycol, cyclohexane dimethanol, ethylene oxide adduct of bisphenol A, glycerol, and trimethylolpropane.

The polyfunctional component is a tribasic or higher polybasic acid or polyhydric alcohol, trimellitic acid, pyromellitic acid, hemimellitic acid, 1,1,2,2-ethanetetracarboxylic acid, 1,1,2- Polybasic acids such as ethanetricarboxylic acid, 1,3,5-pentanetricarboxylic acid, 1,2,3,4-cyclopentanetetracarboxylic acid, biphenyl-3,4,3 ′, 4′-tetracarboxylic acid, Polyhydric alcohols such as pentaerythritol, glycerol, trimethylolpropane, 1,2,6-hexanetriol, sorbitol, 1,1,4,4-tetrakis (hydroxymethyl) cyclohexane are exemplified.
The content of the polyfunctional component is preferably 0.01 to 0.50 mol%, particularly 0.05 to 0.40 mol% per polyester, and if less than the above range, the melt tension is 50 mN. It is difficult to achieve the above, and it is not possible to effectively prevent the occurrence of film sway and pulsation due to high-speed extrusion lamination. On the other hand, if it exceeds the above range, the melt-extrusion characteristics deteriorate, and the mechanical properties and heat resistance as a coating layer Tends to decrease.

The polyester containing the polyfunctional component used in the present invention may be a homopolyester, a copolyester, or a blend of two or more of these, but is preferably a polyester mainly composed of ethylene terephthalate units. It is desirable that the polyester be a copolymer polyester containing isophthalic acid as a copolymer component. The copolymer component is preferably contained in an amount of 10 to 20 mol%.
In addition, this polyester resin has an intrinsic viscosity of 0.5 to 2.0 dl / g, particularly 0.6 to 1 in terms of the physical properties of the coating layer and the melt-extrusion properties, measured using a phenol / tetrachloroethane mixed solvent. Preferably it is in the range of 5 dl / g. Furthermore, it preferably has a melting point (Tm) of 160 to 270 ° C., particularly 200 to 250 ° C., from the viewpoints of heat resistance, workability and melt extrusion characteristics. The glass transition point is preferably 30 ° C. or higher, particularly 50 to 120 ° C.

  The first polyester resin layer used in the present invention has a resin compounding agent known per se, for example, an antiblocking agent such as amorphous silica, a pigment such as titanium dioxide (titanium white), an antioxidant, and a stabilizer. In addition, various antistatic agents, lubricants, and the like can be blended according to known formulations.

(Second polyester resin)
The second polyester resin is a polyester having a melt tension smaller than that of the first polyester resin and a melt tension ratio of 1.1: 1 to 5: 1 in relation to the first polyester resin layer. It is preferable to use a resin.
Specifically, a conventionally known polyester resin comprising a dicarboxylic acid component and a diol component exemplified for the first polyester resin can be used. In particular, in the second polyester resin layer, the multilayer film has a flavor property. It is particularly preferable that the polyester is mainly composed of ethylene terephthalate, in which 80% or more of the dicarboxylic acid component is terephthalic acid and 80% or more of the diol component is ethylene glycol. Moreover, the copolymerization component may be contained similarly to the 1st polyester resin, and the content is 20 mol% or less.

The second polyester resin has an intrinsic viscosity of 0.5 to 2.0 dl / g, particularly 0.6, measured using a phenol / tetrachloroethane mixed solvent from the viewpoint of physical properties of the coating layer and melt extrusion characteristics. It is preferably in the range of 1.5 dl / g. Further, it preferably has a melting point (Tm) of 160 to 270 ° C., particularly 200 to 260 ° C. from the viewpoint of heat resistance, workability and melt extrusion characteristics. The glass transition point is preferably 30 ° C. or higher, particularly 50 to 120 ° C.
In the second polyester resin layer as well as the first polyester resin layer, the above-mentioned conventionally known compounding agents for resins can be blended according to a known formulation.

(Metal base)
In the present invention, as the metal substrate on which the multilayer film is to be laminated, various surface-treated steel plates, light metal plates such as aluminum, or these foils are used.
Surface-treated steel sheets are steel sheets that have been cold-rolled steel sheets after temper rolling or secondary cold rolling, that is, SR materials and DR materials, galvanized, tin-plated, nickel-plated, electrolytic chromic acid treatment, chromic acid treatment A surface treatment such as one or more of the surface treatments can be used. An example of a suitable surface-treated steel sheet is an electrolytic chromic acid-treated steel sheet, which has a metal chromium layer of 10 to 200 mg / m ² and a chromium oxide layer of 1 to 50 mg / m ² (in terms of metal chromium). This product is excellent in the combination of coating film adhesion and corrosion resistance. Another example of the surface-treated steel plate is a hard tin plate having a tin plating amount of 0.6 to 11.2 g / m ² . This tin plate is preferably subjected to chromic acid treatment or chromic acid / phosphoric acid treatment so that the amount of chromium is 1 to 30 mg / m ^{2 in} terms of metallic chromium. As yet another example, an aluminum-coated steel sheet subjected to aluminum plating, aluminum pressure welding, or the like is used.

As the light metal plate, an aluminum alloy plate is used in addition to a so-called pure aluminum plate. The aluminum alloy plate excellent in terms of corrosion resistance and workability is Mn: 0.2 to 1.5% by weight, Mg: 0.8 to 5% by weight, Zn: 0.25 to 0.3% by weight , And Cu: 0.16 to 0.26% by weight, with the balance being Al. These light metal plates are also desirably subjected to chromic acid treatment or chromic acid / phosphoric acid treatment so that the chromium amount is 20 to 300 mg / m ^{2 in} terms of metal chromium.

  The thickness of the metal plate varies depending on the type of metal and the use or size of the laminate material, but generally it should have a thickness of 0.10 to 0.50 mm. .10 to 0.30 mm, and in the case of a light metal plate, the thickness should be 0.15 to 0.40 mm.

  When laminating a film made of the first polyester resin and the second polyester resin and a metal substrate by an extrusion laminating method, an adhesive primer can be provided on the metal substrate as desired. It exhibits excellent adhesion to both the substrate and the polyester resin. A typical primer paint excellent in adhesion and corrosion resistance is a phenol epoxy paint comprising a resol type phenol aldehyde resin derived from various phenols and formaldehyde, and a bisphenol type epoxy resin. In particular, it is a paint containing a phenol resin and an epoxy resin in a weight ratio of 50:50 to 5:95, particularly 40:60 to 10:90. The adhesive primer layer is generally preferably provided with a thickness of 0.3 to 5 μm.

(Lamination method)
[Multilayer film]
The multilayer film of the present invention is obtained by coextrusion molding, using the number of extruders corresponding to the type of resin, and using the first polyester as in the normal T-die method and inflation method except that a multilayer multiple die is used. After melt-kneading the resin and the second polyester resin with an extruder, the resin and the second polyester resin can be formed by extruding into a multilayer film shape through a T-die or an annular die. It is of course possible to form a film made of the first polyester resin and the second polyester resin by extrusion molding such as a T-die method or an inflation film forming method and to laminate them by bonding them.
As a multilayer film, the extruded film can be used as an unstretched film by a cast molding method in which the extruded film is rapidly cooled, and this film is biaxially stretched sequentially or simultaneously at the stretching temperature, and the stretched film is heat-set. It can also be used as a biaxially stretched film produced by

[Laminate]
The laminate material formed by laminating the multilayer film of the present invention on a metal substrate is a dry lamination of the multilayer film previously formed from the first polyester resin and the second polyester resin, or each film on the metal substrate. The multilayer film of the present invention is excellent in the extrusion laminating property at high speed as described above, and may be formed by the extrusion lamination method described later. Particularly preferred. As a result, processing at a very high speed is possible, and work associated with film formation, such as film winding, and costs for it can be reduced.

In FIG. 4 which shows arrangement | positioning of the apparatus used for the extrusion lamination method, along the channel | path 12 of the metal base | substrate 11, the heating area | region 13 of the metal base | substrate and the 1st polyester resin made to lie relative to the channel | path 12 of a metal base | substrate A pair of multi-layer dies 15a and 15b, and a film extruded from the dies 15a and 15b, which are fed into the film form, by the extruders 14a and 14b and the second polyester resin extruders 14c and 14d. The pre-rolls 16a and 16b received from the opposite side (second polyester resin side) and over the entire width of the film, the films 17a and 17b from the pre-rolls 16a and 16b, and the first polyester resins 14a and 14b on both surfaces of the metal substrate 11 And a pair of laminating rolls 18a and 18b to which the second polyester resins 14c and 14d are bonded, and a laminator to be formed A quench unit 20 for quenching the wood 19 is placed.
In the apparatus shown in FIG. 4, the layers made of the first polyester resin and the second polyester resin are respectively formed on both surfaces of the metal substrate. A layer made of a polyester resin can also be formed. In this case, either one of the dies may not be used.

In the apparatus shown in FIG. 4, the metal substrate 11 is passed between the pair of laminate rolls 18a and 18b and in a direction substantially perpendicular to the line connecting the centers of the laminate rolls 18a and 18b, and from the dies 15a and 15b. The polyester resin melt film 17 is received by the pre-rolls 16a and 16b, supported and conveyed by the corresponding laminating rolls 18a and 18b, and supplied to the nip position 21 between the laminating rolls. The multilayer film 17 is fused at the same time.
As a result, it is possible to prevent deterioration of performance due to excessive heating of the metal substrate and the polyester resin, and it is possible to simultaneously coat the polyester resin on both surfaces of the metal substrate, and the resin temperature necessary for adhesion to the metal substrate by the pre-roll. The resin film is cooled while securing the film, and it is possible to prevent film shaking and excessive neck-in at the time of extrusion lamination, thereby improving the yield of products without reducing the film width of the flat portion. In addition, it is possible to produce a laminate material having a high polyester resin coating and high performance, that is, thickness uniformity, high workability, high adhesion, high film properties, and the like at high speed.

In the production of the laminate material using the apparatus shown in FIG. 4, the metal substrate 11 heated in the heating zone 13 is guided to the nip position of the laminate rolls 18a and 18b, but the metal substrate passage 2 and the laminate roll 18a, 18b is provided in the above positional relationship, the metal substrate 11 is prevented from coming into contact with other members until the nip position 21 of the laminate rolls 18a and 18b is reached, and the surface temperature of the metal substrate 11 is reduced. Therefore, the slowest speed corresponding to the cooling rate in the air is maintained.
For this reason, the temperature and heat capacity of the metal substrate 11 can be effectively used for heat fusion with the polyester resin thin film, and it is high without requiring reheating between the polyester resin film 17 and the metal substrate 11. Adhesive strength can be obtained.

  Resin metal laminate material discharged from the laminating roll is introduced into a quenching means and rapidly cooled, so that the resin coating is a thin film and has high performance, that is, thickness uniformity, high workability, high adhesion, and high film properties. Or the like.

(Can body and can lid)
The can body of the present invention can be produced by making the above-mentioned laminate material into a two-piece can or a three-piece can by a conventionally known molding method.
In particular, seamless cans having no side seams are preferable, and they are manufactured by means such as drawing, drawing / deep drawing, drawing / ironing, drawing / bending / drawing / ironing. The side wall of the resin-coated metal sheet is thinned so as to have a thickness of 20 to 95%, particularly 30 to 85% of the original thickness of the resin-coated metal sheet by bending and stretching by drawing-redrawing or further ironing. It is preferable that

In addition, the can lid of the present invention can be formed from the above-described laminate material by a conventionally known method for producing can lids.
Moreover, the shape of a can lid can employ | adopt conventionally well-known shapes, such as an easy open end provided with the score for forming the opening for content extraction, and the tab for opening.

The invention is illustrated by the following examples.
The characteristic values of the present invention are based on the following measurement methods.

(1) Melting point (Tm)
Using a differential scanning calorimeter DSC7 (manufactured by Perkin Elmer), about 5 mg of resin was heated at a rate of 10 ° C./min under a nitrogen stream, and the maximum endothermic peak temperature based on crystal melting at that time was determined. Tm.

(2) Intrinsic viscosity (IV)
The resin was dissolved in a 1: 1 mixed solution of phenol and tetrachloroethane in a weight ratio and measured at 30 ° C. with an Ubbelohde viscometer.

(3) Melt tension Resin is supplied to a segment twin screw extruder 2D25W type [manufactured by Toyo Seiki Seisakusho] and melt extruded at a discharge rate of 1.5 kg / hr and a resin temperature of 240 ° C., and L / D = 15 mm / 3 mm. The molten resin from the strand die was taken out at 100 m / min, and the melt tension was measured with a load cell at a position 450 mm from the die outlet.

(4) High-speed laminating properties Using a T-die twin screw extruder as shown in Fig. 4, the resin melted at 260 ° C is extruded onto an aluminum alloy plate at 100 m / min for laminating, and the occurrence of film shaking and pulsation is observed. confirmed. The evaluation criteria are shown below.
[Membrane shake]
The width of the film sway was evaluated as a ratio to the width of the obtained resin film.
Less than 2%
2% or more
[pulsation]
The thickness of the resin film of the obtained laminate material was measured over the longitudinal direction of 500 mm, and evaluated by the ratio of the fluctuation width of the measured thickness to the average thickness of the resin film.
Less than 10%
10% or more ・ ・ ・ ×

(5) Can-making suitability Using a resin-coated aluminum alloy plate obtained by extrusion lamination, a 350 ml can having an inner diameter of 66 mm and a height of 122 mm was DI-molded, and processability and adhesion were evaluated according to the following criteria.
In the DI molding, a resin-coated aluminum alloy plate coated with a lubricant was drawn and then redrawed in a dry state and subjected to three-stage ironing to produce a can.
[Machinability]
Evaluation was made based on the presence or absence of broken bodies and buckling during can making.
Can can be made without breaking and buckling.
Blasting or buckling occurred ... ×
[Adhesion]
The film peeling and lifting during can making were visually evaluated.
No film peeling or lifting was observed.
Film peeling and lifting were observed ... ×

(6) Flavored cans were filled with ultrapure water in cans with good suitability, opened after retorting (125 ° C-30 minutes), and sensory for differences in taste, turbidity, and fragrance before and after retorting. evaluated.
No difference was found ...
Differences were observed ... ×

[Example 1]
Polyester mainly composed of ethylene terephthalate units on an aluminum alloy plate (A3004H19 material) having a thickness of 0.280 mm heated to 250 ° C., trimellitic acid as a polyfunctional component, and isophthalic acid as a copolymer component are listed in Table 1. A first polyester resin containing the composition shown in FIG. 1 and a second polyester resin mainly composed of an ethylene terephthalate unit containing an isophthalic acid component as a copolymerization component shown in Table 1 are extruded at 65 mmφ equipped with an extrusion lamination facility. Each was supplied to a machine, and then melt-extruded to a thickness of 16 μm at a temperature 30 ° C. higher than the melting point of the resin, and laminated on both sides of the aluminum alloy plate.
The evaluation results are shown in Table 2. Film lamination and pulsation did not occur at 100 m / min, and good lamination was possible. The ability to make cans and flavor were also good.

[Example 2]
The same procedure as in Example 1 was performed except that the amounts of the polyfunctional component and copolymer component of the first polyester resin used and the copolymer component of the second polyester resin were changed to the contents shown in Table 1. Table 2 shows the evaluation results. Film lamination and pulsation did not occur at 100 m / min, and good lamination was possible. The ability to make cans and flavor were also good.

[Example 3]
The same procedure as in Example 1 was performed except that the amounts of the polyfunctional component and copolymer component of the first polyester resin used and the copolymer component of the second polyester resin were changed to the contents shown in Table 1. Table 2 shows the evaluation results. Film lamination and pulsation did not occur at 100 m / min, and good lamination was possible. The ability to make cans and flavor were also good.

[Example 4]
The same procedure as in Example 1 was performed except that the amounts of the polyfunctional component and copolymer component of the first polyester resin used and the copolymer component of the second polyester resin were changed to the contents shown in Table 1. Table 2 shows the evaluation results. Film lamination and pulsation did not occur at 100 m / min, and good lamination was possible. The ability to make cans and flavor were also good.

[Comparative Example 1]
The same procedure as in Example 1 was performed except that the amounts of the polyfunctional component and copolymer component of the first polyester resin used and the copolymer component of the second polyester resin were changed to the contents shown in Table 1. Table 2 shows the evaluation results. Since no polyfunctional component was contained in the first polyester resin, the melt tension was low, and severe film shaking occurred at 100 m / min. Therefore, film thickness unevenness occurred in the coating resin of the laminate material, and a broken cylinder occurred during can making.

[Comparative Example 2]
The same procedure as in Example 1 was performed except that the amounts of the polyfunctional component and copolymer component of the first polyester resin used and the copolymer component of the second polyester resin were changed to the contents shown in Table 1. Table 2 shows the evaluation results. The polyfunctional component was contained in the first polyester resin, but the melt tension was low, and film shaking occurred at 100 m / min. Therefore, film thickness unevenness occurred in the coating resin of the laminate material, and a broken cylinder occurred during can making.

[Comparative Example 3]
The same procedure as in Example 1 was performed except that the amounts of the polyfunctional component and copolymer component of the first polyester resin used and the copolymer component of the second polyester resin were changed to the contents shown in Table 1. Table 2 shows the evaluation results. Since the content concentration of the polyfunctional component in the first polyester resin was high, the melt tension became very high, and the melt tension ratio between the first polyester resin and the second polyester resin became very large. Severe pulsation occurred at 100 m / min. Therefore, film thickness unevenness occurred in the coating resin of the laminate material, and a broken cylinder occurred during can making.

[Comparative Example 4]
The same procedure as in Example 1 was performed except that the amounts of the polyfunctional component and copolymer component of the first polyester resin used and the copolymer component of the second polyester resin were changed to the contents shown in Table 1. Table 2 shows the evaluation results. Although the polyfunctional component was contained in the first polyester resin, the melt tension was very low, and film shaking occurred at 100 m / min. Therefore, film thickness unevenness occurred in the coating resin of the laminate material, and a broken cylinder occurred during can making.

[Comparative Example 5]
The same procedure as in Example 1 was performed except that the amounts of the polyfunctional component and copolymer component of the first polyester resin used and the copolymer component of the second polyester resin were changed to the contents shown in Table 1. Table 2 shows the evaluation results. Although the high-speed laminating property was good, since the copolymer component was not contained in the first polyester resin, film peeling and lifting were observed during can making.

[Comparative Example 6]
The same procedure as in Example 1 was conducted except that the amounts of the polyfunctional component and copolymer component of the first polyester resin used and the copolymer component of the second polyester resin were changed to the contents shown in Table 1. Table 2 shows the evaluation results. Although the high-speed laminating property was good, since the content of the copolymer component in the first polyester resin was low, film peeling and lifting were observed during canning.

[Comparative Example 7]
The same procedure as in Example 1 was performed except that the amounts of the polyfunctional component and copolymer component of the first polyester resin used and the copolymer component of the second polyester resin were changed to the contents shown in Table 1. Table 2 shows the evaluation results. High-speed laminating properties were good, but because the content of the copolymer component in the first polyester resin was high, the melting point was remarkably lowered and the heat resistance was poor. .

[Comparative Example 8]
The same procedure as in Example 1 was conducted except that the amounts of the polyfunctional component and copolymer component of the first polyester resin used and the copolymer component of the second polyester resin were changed to the contents shown in Table 1. Table 2 shows the evaluation results. Although high-speed laminating properties and suitability for can-making were good, turbidity occurred in ultrapure water in the retort treatment for evaluating the flavor. This was considered to be due to an elution component from the second polyester resin having a high content of the copolymer component, and the flavor property was poor.

It is a figure which shows an example of the cross-sectional structure of the laminate material of this invention. It is a figure which shows another example of the cross-section of the laminate material of this invention. It is a figure which shows another example of the cross-section of the laminate material of this invention. It is a figure which shows an example of the apparatus which manufactures the laminate material of this invention.

Claims (5)

An ethylene terephthalate-based polyester resin containing 0.01 to 0.50 mol% of a tribasic or higher polybasic acid or polyhydric alcohol and 10 to 20 mol% of isophthalic acid, and melted at 240 ° C. the first polyester resin tension in the range of 50 to 212MN, a multilayer film Ru formed by laminating other second polyester resin, melting the first polyester resin of the first polyester resin tension ratio of melt tension of the second greater than the melt tension of the polyester resin and the first polyester resin and second polyester resin, 1.1: 1 to 5: multilayer, wherein 1 der Rukoto the film. The first polyester resin and the ratio of the second polyester resin thickness 50: 1 to 1: 5 a multilayer film according to claim 1, wherein the. A laminate material obtained by laminating the multilayer film according to claim 1 or 2 on a metal substrate. A can body made of the laminate material according to claim 3 . A can lid made of the laminate material according to claim 3 .

Images