JPH08132511A - Manufacture of laminated film - Google Patents

Abstract

PURPOSE: To manufacture a laminated film having very little smell by coating a plastic base material with a heat seal layer directly or through an ethylene resin under a specified working condition by extrusion coating so as to reduce excessive oxidation of the ethylene resin. CONSTITUTION: When an ethylene resin having one layer or more is to be arranged by extrusion coating as an intermediate layer in between a plastic base material and a heat seal layer, a resin temperature (T) just under a die of the intermediate layer satisfies a relationship shown by an expression. In the expression, G represents an air gap (mm) in forming the heat seal layer, L represents a take-off speed (m/min) in laminating the heat seal layer, MFR represents a resin melt flow rate (g/10min) for a resin forming the heat seal layer, SR represents a resin swelling rate 180 deg.C<=Th( deg.C)<=T( deg.C), and D represents a resin density (g/cm<3> ) for a resin forming the heat seal layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a laminated film having a low odor. More specifically, in various substrates having a plastic film on the surface, in extrusion-coating the ethylene resin forming the heat-sealing layer directly or via the ethylene resin as an intermediate layer,
Without using an anchor coating agent that causes odor, and reduces excessive oxidation of the heat-sealing layer that becomes the contact surface with the contents and the extrusion-coated ethylene resin,
It relates to a method for producing a laminated film having a very low odor.

[0002]

2. Description of the Related Art Film-like molded products made of different materials such as plastic, paper and metal foil are stuck together to supplement properties which cannot be obtained by themselves, such as strength, gas barrier property, moisture proof property, heat seal property and appearance. It is common practice to manufacture laminated films, and the products thus obtained are widely used mainly for packaging materials and the like. As a method for producing such a laminated film, there are a dry lamination method, a wet lamination method, a hot lamination method, an extrusion lamination method and the like, and these are applied according to their characteristics. As a method for forming a heat-sealing layer on a base material in packaging materials and the like, an extrusion lamination method, which is advantageous in terms of cost, is widely used.

Polyethylene, polypropylene, ethylene copolymers, ionomer resins and the like are generally used as the polyolefin resin coated by the extrusion lamination method, and one layer or two or more layers are extrusion coated. . Among them, polyethylene is widely and widely used.

In order to promote the adhesiveness to the base material, these resins are generally melt-extruded on the adhesive surface to the base material after applying the anchor coating agent on the base material in advance. is there.

As the anchor coating agent, an organic titanate-based adhesive, an organic isocyanate-based adhesive, a polyethyleneimine-based adhesive or the like is used. These adhesives are usually used after being diluted with an organic solvent such as toluene, methanol or hexane.

When an anchor coating agent is used,
For example, in order to extrude non-polar polyethylene and bond it to a plastic substrate, it is necessary to oxidize the surface with air during processing, so the temperature of the molten web discharged from the die is usually set to 300 ° C or higher. To be done. When processing at a lower temperature, a method of subjecting a molten web to ozone treatment is widely known.

However, these methods using the anchor coating agent cause the odor to remain due to the anchor coating agent component such as the organic solvent remaining in the final product, the laminated film, and the adhesion to the substrate. A low molecular weight product generated by excessive oxidation and decomposition of the polyolefin resin used for imparting causes an odor, which is a problem particularly in the fields of food and medical product packaging.

[0008]

SUMMARY OF THE INVENTION In view of such circumstances, the problem to be solved by the present invention is to provide an ethylene-based resin for forming a heat-sealing layer directly or on an intermediate layer on various base materials having a plastic base material on the surface thereof. As an extruding coating through ethylene resin as a product, without using an anchor coating agent that causes odor, and as a heat seal layer that is the contact surface with the contents and excessive oxidation of the extruding coating ethylene resin It is to provide a method for producing a laminated film having a very low odor by reducing

[0009]

Means for Solving the Problems The present inventors have found that when various ethylene-based resins are extrusion-coated directly or through an ethylene-based resin as an intermediate layer onto various substrates having a plastic substrate on the surface, odor As a result of diligent examination of the various causes of generation in relation to the manufacturing method, sufficient film adhesion strength was obtained without using an anchor coating agent, and the odor generated from the ethylene resin extruded and coated was greatly reduced. The present invention has been completed by finding a possible method for producing a laminated film.

That is, the present invention is a method for producing a laminated film comprising an ethylene-based resin for forming a plastic substrate and a heat-sealing layer, wherein the heat-sealing layer is extruded directly or through the ethylene-based resin onto the plastic substrate. Anchor coating agent is not used for coating, the following processing conditions (1) to (4) are satisfied, and the following (5)
The present invention relates to a method for producing a laminated film, including the steps (7) to (7).

[Processing Conditions] (1) In the case where a heat-sealing layer is extrusion-coated on a plastic substrate in a single layer, or when one or more ethylene-based resins are extrusion-coated as an intermediate layer between the plastic substrate and the heat-sealing layer. Regarding the resin temperature (T) directly below the die of the intermediate layer, the relationship of the following (formula 1) is established: T (° C) ≦ L-0.3 × G-25 × Log (MFR) + 150 × SR + 500 × D− 480 (Formula 1) However, it is as follows. G: Air gap (m when forming the heat seal layer
m) L: take-up speed (m / min) when heat-sealing layer is laminated MFR: melt flow rate of resin forming heat-sealing layer (g / 10 minutes) SR: swelling ratio of resin forming heat-sealing layer D : Density of resin forming heat seal layer (g / c
m ³ )

(2) The resin temperature (Th) immediately below the die at the time of laminating the heat seal layers when extrusion coating one or more ethylene resins as an intermediate layer between the plastic substrate and the heat seal layer is as follows: The relationship of 2) is established: 180 ° C ≤ Th (° C) ≤ T (° C) (Equation 2)

(3) Regarding the cooling roll temperature (C) at the time of stacking the heat-sealing layers, the following relationship (formula 3) must be satisfied: 0 ° C. ≦ C (° C.) ≦ 70 ° C. (formula 3)

(4) Regarding the take-up speed (Ln) when laminating one or more ethylene-based resins as an intermediate layer between the base material and the heat-sealing layer, the following equation (4) is established. What to do Ln (m / min) ≧ L (m / min) (Equation 4)

[Step] (5) Ozone treatment is applied to the surface of the molten web extruded from the co-extrusion die or T die on the side in contact with the substrate when the plastic substrate is extrusion coated with the ethylene resin. Process of applying

(6) A step of subjecting at least one surface of the plastic substrate to a surface oxidation treatment

(7) A step of bringing the surface oxidation-treated surface of the plastic substrate into contact with the ozone-treated surface of the film obtained in the step (5) and press-bonding the film and the plastic substrate.

As the plastic substrate used in the present invention, nylon, polyester resin, saponification product of ethylene-vinyl acetate copolymer, polyvinyl alcohol, polypropylene resin, cellophane, cellulose resin, polyvinylidene chloride, polystyrene, A simple substance of a resin such as polyvinyl chloride, polycarbonate, polymethylmethacrylate, polyurethane, fluorine resin, polyacrylonitrile, or a laminated film or sheet thereof, or a stretched product, a coated product or a woven fabric thereof is used. Further, it is a laminated product of these plastic base materials and aluminum, iron, paper or the like, and a laminate or the like in which these resins and an ethylene resin are provided on the joint surface is used. If necessary, the surface of these plastic substrates may be subjected to surface treatment such as corona discharge treatment, plasma treatment, flame treatment, or may be preliminarily printed. The thickness of the substrate is not particularly limited as long as extrusion laminating can be performed, but the range is preferably 1 to 10000 μ, and more preferably 5 to 500 μ.

The ethylene resin used in the present invention is, for example, high density polyethylene produced by an ionic polymerization method, a copolymer of ethylene and an α-olefin having 3 to 18 carbon atoms, or a high pressure radical polymerization method. Low-density polyethylene, ethylene and unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, t acrylate -C4-8 unsaturated such as butyl, isobutyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, t-butyl methacrylate, isobutyl methacrylate Esterified carboxylic acid,
Copolymers with various comonomers such as vinyl esters such as vinyl acetate, vinyl propionate and vinyl neoate can be used. The comonomer type copolymerized with ethylene can be used either singly or as a plurality of types, but the content of the comonomer component contained in the ethylene resin used in the present invention is preferably 30% by weight or less, More preferably, 20% by weight or less can be preferably used in terms of odor. These ethylene resins can be used alone or as a mixture of two or more kinds. Furthermore, if necessary, a mixture of other resins in a range of less than 50% by weight can be used.

Further, the ethylene-based resin used in the present invention contains known additives such as antioxidants, anti-blocking agents, weathering agents, neutralizing agents, flame retardants, etc. within a range that does not impair the effects of the present invention. Antistatic agents, antifogging agents, lubricants, dispersants, pigments, organic or inorganic fillers, etc. may be used in combination.

The processing conditions in the method for producing a laminated film of the present invention are defined by the following (1) to (4).

(1) A heat-sealing layer which is extrusion-coated on a plastic substrate as a single layer, or an intermediate layer when one or more ethylene resins are extrusion-coated as an intermediate layer between the plastic substrate and the heat-sealing layer. For the resin temperature (T) immediately below the die, the following relationship (Equation 1) is established: T (° C) ≤ L-0.3 x G-25 x Log (MFR) + 150 x SR + 500 x D-480 (Equation 1 ) Preferably T (° C) ≦ L-0.3 × G-25 × Log (MFR) + 150 × SR + 500 × D-487 (formula 1 ′) More preferably T (° C) ≦ L-0.3 × G- 25 * Log (MFR) + 150 * SR + 500 * D-494 (Formula 1 '').

However, the following is done. G: Air gap (m when forming the heat seal layer
m) L: take-up speed (m / min) when heat-sealing layer is laminated MFR: melt flow rate of resin forming heat-sealing layer (g / 10 minutes) SR: swelling ratio of resin forming heat-sealing layer D : Density of resin forming heat seal layer (g / c
m ³ )

Here, the air gap means the distance from the die exit to the crimping point of the cooling roll and the nip roll,
Although it can be set arbitrarily, the molten web extruded from the co-extrusion die or the T die in this gap undergoes air oxidation, and therefore it is preferable to set the distance as short as possible in order to reduce the oxidation of the molten web.

Although the take-up speed can be set arbitrarily,
When the take-up speed is slow, the time taken for the molten web to be exposed to the air in the air gap becomes long and it is easy to be oxidized. Therefore, it is preferable to set the speed as fast as possible in order to reduce the oxidation of the molten web.

The melt flow rate (MFR) of the resin
Is 190 ° C, 2.16 according to JIS K7210.
The ethylene resin used in the present invention may be any MFR resin measured under a load of kg, but it is usually in the range of 0.1 to 100 g / 10 min. MFR
When it is high, the content of low molecular weight components also becomes high, and it tends to become an odor component after being oxidized, and when it is too low, it causes decomposition due to heat generation in the extruder and causes an odor, so that it is used in the present invention. MFR of ethylene resin is 1-50g
/ 10 min, more preferably 2 to 30 g / 10 min.

The swelling ratio (SR) of the resin is M
The diameter of the strand collected during the FR measurement can be measured and determined from the following formula. The ethylene resin used in the present invention can be any SR resin, but usually 1.05 to 2. The range is 00. SR = strand diameter (mm) / orifice inner diameter (mm)

The magnitude of SR does not directly correlate with the odor, but those with a small SR tend to have a strong odor, and a large SR tends to make it difficult to perform high-speed processing. Therefore, the SR of the ethylene resin used in the present invention is preferably in the range of 1.1 to 1.9, more preferably 1.2 to 1.8.

The density of the resin is measured in accordance with JIS K6760 after annealing at 100 ° C. for 1 hour, and the ethylene resin used in the present invention may have any density, but is usually 0.870-. 0.970 g / cm
It is in the range of ³ . When the density is low, the odor tends to be strong, and therefore the higher density is preferable in terms of the odor.

The present inventors have found that various causes of odor generation affect the air gap, the take-up speed, the MFR of the resin, the SR of the resin, and the density of the resin as described above, and obtain a laminated film with less odor. As one of the processing conditions for
Depending on each setting and the physical properties of the resin used, a heat-sealing layer that is extrusion-coated on a plastic substrate as a single layer, or extrusion-coating with one or more ethylene-based resins as an intermediate layer between the plastic substrate and the heat-sealing layer. The resin temperature (T) just below the die of the intermediate layer in the case of performing is represented by (Formula 1). If the temperature of the resin directly under the die is higher than this range, the effect of improving odor cannot be sufficiently obtained, which is not preferable.

From the viewpoint of reducing odor, when a heat-sealing layer is extrusion-coated on a plastic substrate in a single layer, or when one or more ethylene resins are extrusion-coated as an intermediate layer between the plastic substrate and the heat-sealing layer. The resin temperature (T) immediately below the die of the intermediate layer is preferably 290 ° C or lower, and more preferably 285 ° C or lower.

(2) The resin temperature (Th) immediately below the die when the heat-sealing layers are laminated in the case of extrusion coating one or more ethylene-based resins as an intermediate layer between the plastic substrate and the heat-sealing layer is 180 ° C. ≦ Th (℃) ≦ T
(° C.) (Equation 2) If the resin temperature (Th) directly below the die during lamination of the heat-sealing layer is less than 180 ° C., the spreadability of the resin becomes poor, and it is difficult to obtain a molten film having a uniform thickness, which is not preferable. On the other hand, when the temperature is higher than the resin temperature of the intermediate layer just below the die, which is T ° C., it is not preferable because the oxidation of the molten web is increased and the odor is deteriorated.

(3) Cooling roll temperature (C) when laminating the heat seal layer is 0 ° C. ≦ C (° C.) ≦ 70 ° C. (Equation 3) Preferably 5 ° C. ≦ C (° C.) ≦ 60 ° C. (Equation 3 ′) More preferably, 10 ° C. ≦ C (° C.) ≦ 50 ° C. (formula 3 ″). Cooling roll temperature (C) when heat seal layer is laminated
Is less than 0 ° C., the surface of the chill roll is liable to be dewed, which is not preferable. It is not preferable because the oxidation progresses and the odor worsens.

(4) When one or more ethylene-based resins are interposed as an intermediate layer between the substrate and the heat-sealing layer, the take-up speed (Ln) at the time of laminating the intermediate layers is Ln (m / min) ≧ L (m / Min) (Equation 4) When the take-up speed (Ln) at the time of laminating the intermediate layer is lower than the take-up speed (L) at the time of laminating the heat-sealing layer, excessive oxidation of the intermediate layer proceeds and odor is deteriorated, which is not preferable.

The steps (5) to (7) in the method for producing a laminated film of the present invention are steps for imparting film adhesiveness to a plastic substrate without using an anchor coating agent which causes odor. Is.

(5) A step of subjecting a plastic base material to ozone treatment on the surface of the molten web extruded from a co-extrusion die or a T-die, which is in contact with the base material, when the ethylene resin is extrusion coated. In the ozone treatment,
For example, it is performed by continuously blowing a gas containing ozone (such as air) from a nozzle provided in an air gap below the die or a slit-shaped blowout port. At this time, it is preferable that the sprayed ozone-containing gas does not stay in a specific portion and is sprayed over the entire surface of the molten web which is in contact with the base material.
When the ozone nozzle cannot be installed under the die, the ozone nozzle may be sprayed on the plastic substrate immediately before the pressure lamination. The amount of ozone sprayed is 1 ≦ ozone treatment amount (mg / m ² ) ≦ −0.5 × T + 170 (Equation 5), preferably 1 ≦ ozone treatment amount (mg / m ² ), with respect to the passing unit area of the molten film. ≦ −0.5 × T + 165 (Formula 5 ′) More preferably, 1 ≦ ozone treatment amount (mg / m ² ) ≦ −0.5 × T + 160 (Formula 5 ″).

However, the following is performed. T: Resin temperature directly below the die of the ethylene resin used for ozone treatment
Degree (℃) Ozone treatment amount is 1 mg / m²Less than plastic
It is not preferable because the film adhesive strength with the base material cannot be sufficiently obtained.
And also [-0.5 x Tx + 170] mg / m ²Over
If so, the surface of the molten web is excessively oxidized and the odor becomes worse.
Is not preferred.

(6) In the step of subjecting at least one surface of the plastic substrate to the surface oxidation treatment, the surface oxidation treatment is
In order to generate a certain level or more of oxidation active points on the adhesive surface of the plastic substrate, it can be performed by a known method such as corona discharge treatment, plasma treatment, flame plasma treatment, electron beam irradiation treatment, and ultraviolet irradiation treatment. . However, after the surface oxidation treatment, it is preferable to complete the pressure bonding in the step (7) as soon as possible.

The corona discharge treatment is carried out, for example, by using a known corona discharge treatment device and passing a plastic substrate through the generated corona atmosphere. Here, from the viewpoint of maintaining the film adhesive strength at a high level, the corona discharge density is 10 W · min / m ² or more, preferably 25
W · min / m ² or more, more preferably 40 W · min
/ M ² or more.

The plasma treatment is carried out by electrically exciting a simple substance or a mixed gas such as argon, helium, krypton, neon, xenon, hydrogen, nitrogen, and air with a plasma jet, then removing charged particles and electrically It can be carried out by spraying the activated inert gas that has been made into a conductive material onto the surface of the plastic substrate.

The flame plasma treatment can be carried out by spraying the ionized plasma in the flame produced when burning natural gas or propane onto the surface of the plastic substrate.

The electron beam irradiation treatment is carried out by irradiating the surface of the plastic substrate with an electron beam generated by an electron beam accelerator. As the electron beam irradiation device, for example, a device "Electro Curtain" (trade name) that can irradiate a curtain-shaped uniform electron beam from a linear filament can be used.

The ultraviolet irradiation treatment is, for example, 200 to 400.
It can be carried out by irradiating the surface of the plastic substrate with ultraviolet rays having a wavelength of mμ.

When the surface oxidation treatment is not carried out, it is not preferable because the film adhesion strength with the ethylene resin laminated on the plastic substrate cannot be sufficiently obtained.

Further, some commercially available plastic substrates have been subjected to surface oxidation treatment such as corona discharge treatment in order to improve printability on the surface. When used without carrying out the oxidation treatment, the sufficiently strong film adhesion strength aimed at by the present invention cannot be obtained.

(7) In the step of bringing the surface-oxidized surface of the plastic substrate into contact with the ozone-treated surface of the film obtained in the step (5) and press-bonding the film and the plastic substrate, This can be done using known extrusion laminators, including, for example, crimping between chill rolls and nip rolls. In the present invention,
It is preferable to immediately subject the plastic substrate after the surface oxidation treatment step, which is the step (6), to the pressure-bonding step. As a result, a higher level of film adhesion strength is exhibited and undesired blocking of the film is prevented.

In the present invention, an apparatus in which a plastic substrate feeding step, a surface oxidation treatment step, a pressure bonding step and a product winding step are sequentially installed on the same line along the direction of flow of the plastic substrate is used. It is preferable to perform these steps promptly in a series of operations.

In the present invention, when the extrusion coating of the ethylene resin is performed, an exhaust device usually installed above the die of a known extrusion laminator is operated,
Exhausting fumes and the like generated during processing is preferable from the viewpoint of preventing deterioration of odor.

Further, in the present invention, from the viewpoint of further improving the film adhesion strength, a step of aging the laminated film obtained in the pressure-bonding step under heat retention may be provided after the pressure-bonding step. Aging temperature is usually 25 to 70 ° C., preferably 30 to
The temperature is 50 ° C, more preferably 40 to 45 ° C. If the aging temperature is too low, sufficient film adhesive strength may not be obtained, while if it is too high, the heat-sealing performance and hot tack performance of the coated resin may be deteriorated. The aging time is usually 1 to 120 hours, preferably 1
It is 0 to 120 hours. If the aging time is too short, the improvement of the film adhesive strength may be insufficient, while if it is too long, the coated resin may be deteriorated and it is disadvantageous in terms of productivity. To carry out the aging step, a normal oven or a room capable of controlling temperature may be used, but it should not be performed in a place where an odor is originally generated.

Further, in the present invention, from the viewpoint of further improving the film adhesive strength, a plastic substrate to be subjected to the surface oxidation treatment step is added before the surface treatment step of the step (6).
You may heat at the temperature of 40 degreeC or more and below the melting point of a plastic base material.

In the present invention, since a laminated film having less odor can be obtained as compared with the laminated film produced by the conventional method, it can be suitably used for packaging materials such as food packaging materials, pharmaceutical packaging materials and industrial materials. it can.

[0052]

EXAMPLES The present invention will now be described in more detail with reference to examples.

Example 1 Biaxially stretched polyester (PET; E5100 type 25μ) manufactured by Toyobo Co., Ltd. was used as a plastic substrate, and Sumikasen L7 manufactured by Sumitomo Chemical Co., Ltd. was used as an ethylene resin.
18-H (MFR 8 g / 10 min, SR1.58, density 0.919 g / cm ³ ) was used to melt-knead the ethylene-based resin with an extruder having a diameter of 65 mmφ, and the resin temperature was set directly below the die from the T die at 280 ° C., air gap. 160 mm, film width 350 mm, coating layer thickness 30 μ, extruding under the conditions of a take-up speed of 150 m / min, and then 30 mm below the die on the surface of the molten web that comes into contact with the substrate.
The amount of ozone treatment is 20 mg /
The air containing ozone is blown under the condition of m ² and then the corona discharge device provided in-line of the extrusion laminator is used as the surface oxidation treatment of the plastic substrate under the condition that the surface of the substrate is 55 W · min / m ^2. Extrusion coating was applied to the surface of the plastic substrate that had been subjected to the electric discharge treatment, and then pressure-bonded by passing between a cooling roll and a nip roll at a temperature of 20 ° C. to obtain a laminated film.
Further, during the main processing, the exhaust device installed above the die was operated to exhaust the generated smoke. Further, the obtained laminated film was aged in an air atmosphere at 40 ° C. for 48 hours using an oven.

The obtained laminated film was measured and evaluated as follows. Table 1 shows the processing conditions and the evaluation results of the film adhesion strength, and Table 2 shows the evaluation results of the odor.

(1) Evaluation of Membrane Adhesion Strength A laminated film having a width of 15 mm was measured at 200 mm / mi using an auto strain type tensile tester manufactured by Toyo Seiki Co., Ltd.
The peel strength at the time of peeling 180 degrees at a tensile speed of n was measured to evaluate the film adhesive strength.

(2) Odor evaluation In an odorless glass 1 liter wide-mouthed bottle, 10 cm × 5 cm
The laminated film cut out in the size of 1 was put therein, and after sealing with an aluminum foil, the condition was adjusted in an oven at 50 ° C. for 1 hour. After that, a sensory test was conducted by eight panelists to compare odors. The evaluation was expressed by the number of people who had good odor and had good odor.

Comparative Examples 1 to 5 The same procedure as in Example 1 was carried out except that the conditions shown in Table 1 were used. However, in Comparative Examples 4, 5 and 5, a polyurethane-based anchor coating agent (T12 manufactured by Nippon Soda) was previously added to the substrate.
0, T300) was applied. Table 1 shows the processing conditions and the evaluation results of the film adhesion strength, and Table 2 shows the evaluation results of the odor. The column marked with "-" in the table indicates that the process was not performed.

Example 2 Biaxially stretched nylon (ONy; Emblem ON type 15μ) manufactured by Unitika Ltd. was used as the plastic substrate, and Sumikasen L5816 manufactured by Sumitomo Chemical Co., Ltd. was used as the ethylene resin used as the intermediate layer. Sumitomo Chemical Co., Ltd. Sumikasen L CL8071 (MFR 10 g /
10min, SR 1.47, density 0.915g / c
m ³ ), the ethylene-based resin is melt-kneaded with two extruders having a diameter of 65 mmφ, and a multi-slot type co-extrusion die is used, the intermediate layer is a resin temperature just below the die of 285 ° C., and a film width of 3
70 mm, coating thickness 25μ, heat seal layer resin temperature 275 ° C directly under the die, air gap 160 m
m, film width 350 mm, coating layer thickness 25
Extruded under the conditions of μ and a take-up speed of 170 m / min, and then the ozone treatment amount was 17.5 mg from a nozzle provided 30 mm below the die on the surface of the intermediate layer on the side that comes into contact with the substrate. / M ² of air containing ozone is blown, and then the surface of the base material is 48 W · min / m ² by a corona discharge device provided in-line in the extrusion laminator as the surface oxidation treatment of the plastic base material. The surface of the plastic base material subjected to the corona discharge treatment was subjected to extrusion coating, and then pressure-bonded by passing between a cooling roll and a nip roll at a temperature of 20 ° C. to obtain a laminated film. Further, during the main processing, the exhaust device installed above the die was operated to exhaust the generated smoke. Further, the obtained laminated film was aged in an air atmosphere at 45 ° C. for 48 hours using an oven.

About the obtained laminated film, Example 1
Measurement and evaluation were performed in the same manner as in. Table 3 shows the evaluation results of the processing conditions and the film adhesion strength, and Table 4 shows the evaluation results of the odor.

Comparative Examples 6 to 9 The procedure of Example 2 was repeated except that the conditions shown in Table 3 were used. However, in Comparative Example 9, a polyurethane-based anchor coating agent (T120, T3 manufactured by Nippon Soda) was previously applied to the base material.
00) was applied. Table 3 shows the evaluation results of the processing conditions and the film adhesion strength, and Table 4 shows the evaluation results of the odor. The column marked with "-" in the table indicates that the process was not performed.

[0061]

[Table 1]

[0062]

[Table 2]

[0063]

[Table 3]

[0064]

[Table 4]

[0065]

As described above, according to the present invention, a method for producing a laminated film composed of a plastic substrate and an ethylene resin for forming a heat-sealing layer, wherein a laminated film having very little odor can be obtained. Could provide a way.

Continuation of front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical indication B32B 27/36 9349-4F 31/00 9349-4F 31/20 9349-4F C08J 7/00 A 303 7/04 CES R // B29K 23:00 B29L 9:00 (72) Inventor Yuji Shigematsu 1-5 Anezaki Kaigan, Ichihara City, Chiba Sumitomo Chemical Co., Ltd.

Claims (8)

[Claims] 1. A method for producing a laminated film comprising a plastic base material and an ethylene-based resin for forming a heat-sealing layer, wherein the heat-sealing layer is extrusion coated on the plastic base material directly or through the ethylene-based resin. Without using an anchor coating agent, the following (1) to (4)
The manufacturing method of the laminated film which satisfy | fills the processing conditions of these, and includes the following processes (5)-(7). [Processing conditions] (1) A heat-sealing layer which is extrusion-coated on a plastic substrate in a single layer, or an intermediate layer when one or more ethylene-based resins are extrusion-coated as an intermediate layer between the plastic substrate and the heat-sealing layer. Regarding the resin temperature (T) directly below the die of the layer, the following relationship (Formula 1) is established: T (° C) ≤ L-0.3 x G-25 x Log (MFR) + 150 x SR + 500 x D-480 (formula) 1) However, the following shall apply. G: Air gap (m when forming the heat seal layer
m) L: take-up speed (m / min) when heat-sealing layer is laminated MFR: melt flow rate of resin forming heat-sealing layer (g / 10 minutes) SR: swelling ratio of resin forming heat-sealing layer D : Density of resin forming heat seal layer (g / c
m ³ ) (2) The resin temperature (Th) immediately below the die at the time of stacking the heat seal layers when extrusion coating one or more ethylene resins as an intermediate layer between the plastic substrate and the heat seal layer The relationship of 2) is established: 180 ° C. ≦ Th (° C.) ≦ T (° C.) (Equation 2) (3) Regarding the cooling roll temperature (C) at the time of stacking the heat seal layers, the relationship of the following (Equation 3) is established. 0 ° C. ≦ C (° C.) ≦ 70 ° C. (Equation 3) (4) When at least one ethylene-based resin is interposed as an intermediate layer between the base material and the heat-sealing layer, the take-up speed during lamination of the intermediate layer ( Regarding Ln), the relationship of the following (formula 4) is established: Ln (m / min) ≧ L (m / min) (formula 4) [Step] (5) Extruding an ethylene resin onto a plastic substrate Co-extrusion die or Step of subjecting the surface of the molten web extruded from the T-die to the side in contact with the base material, (6) Step of subjecting at least one surface of the plastic base material to surface oxidation treatment, (7) Surface oxidation treatment surface of the plastic base material And a step of bringing the film obtained in the step (5) into contact with the ozone-treated surface and press-bonding the film and the plastic substrate. 2. The method according to claim 1, wherein the ozone treatment amount in the step (5) satisfies the following (formula 5). 1 ≦ ozone treatment amount (mg / m ² ) ≦ −0.5 × T + 170 (Equation 5) However, the following applies. T: Resin temperature (° C) directly below the die of the ethylene resin used for ozone treatment 3. A heat-sealing layer which is extrusion-coated on a plastic substrate as a single layer, or when one or more ethylene resins are extrusion-coated as an intermediate layer between the plastic substrate and the heat-sealing layer The manufacturing method according to claim 1, wherein the resin temperature (T) directly below the die is 290 ° C or lower. 4. The method according to claim 1, including the step of providing the surface oxidation treatment step of step (6) and the pressure bonding step of step (7) in-line, and immediately subjecting the plastic substrate after the surface oxidation processing step to the pressure bonding step. Production method. 5. The production method according to claim 1, wherein the surface oxidation treatment in the step (6) is corona discharge treatment. 6. The production method according to claim 1, wherein the exhaust is performed when the extrusion coating of the ethylene-based resin is performed. 7. The manufacturing method according to claim 1, further comprising the following step (8) after the pressure bonding step of step (7). (8) A step of aging the laminated film obtained in the pressure bonding step under heat retention. 8. The method according to claim 1, wherein the ethylene resin used for forming the heat seal layer is a high pressure radical method low density polyethylene, an ethylene-α-olefin copolymer or a mixture thereof.