JP2829351B2 - Resin laminate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a resin laminate, and more specifically, is excellent in heat sealability (particularly low-temperature sealability), foreign matter sealability and pinhole resistance, and The present invention relates to a resin laminate having good film-forming properties and secondary processing properties, and which can be suitably used for packaging liquids such as various foods, beverages, and medicines, and powders.

[Problems to be Solved by the Related Art and the Invention] Conventionally, as packaging materials for various kinds of foods, beverages, chemicals, cements, liquids such as sand, powders and the like, paper, synthetic resin sheets or synthetic resin films, A laminate of paper and a synthetic resin sheet or a synthetic resin film or the like is used. Above all, packaging materials made of synthetic resins, particularly polyolefin sheets or polyolefin films, are used in many industrial fields because they have excellent moldability, high productivity, water resistance, chemical resistance and the like.

By the way, a good heat sealing property is required for a film for packaging various articles such as foods and beverages.

Good heat sealability requires a low seal temperature, a wide seal temperature range, high seal strength, and good sealability of contaminants, especially when packaging liquids, and no seal thinning during sealing. Have been. Furthermore, in addition to the above requirements, film forming stability, rigidity for secondary processing, etc. are also required, and these properties are contrary to the improvement in heat sealability. Therefore, the balance between secondary workability and heat sealability is required. Desired properties are desired.

Conventionally, various improvements have been made to obtain a packaging material which is excellent in heat sealability, excellent in transparency, rigidity, impact resistance and the like.

For example, according to Japanese Patent Application Laid-Open No. 55-12008, a titanium catalyst component formed from a magnesium compound and a titanium compound in a multilayer film packaging bag comprising an inner layer and an outer layer, in order to improve the heat sealability of the inner layer. and in the presence of an organic aluminum compound catalyst, where obtained by copolymerizing ethylene and 5 to 10 carbon atoms α- olefin, inner layer consisting of a random copolymer having a density of 0.915 to 0.940 g / cm ³ Used. The density of the random copolymer is preferably in the range of 0.920 to 0.935 g / cm ³ , the melt index is preferably in the range of 1.0 to 5.0, and the thickness of the inner layer is in the range of 5 to 40 μm Is stated to be preferred. Further, as the outer layer, a film of a paper, an aluminum foil, or a polymer having a film-forming ability (for example, polyethylene, polypropylene, polyvinyl chloride, polyvinylidene chloride, nylon, polyethylene terephthalate) is used. Then, the inner layer and the outer layer are laminated to form a multilayer film, and the inner layer surfaces are heat-sealed to form a packaging bag.

Also, JP-A-57-59943 and JP-A-60-36549
According to the publication, an ethylene-α-olefin copolymer is disclosed as a material for lamination having good heat sealability, and in the former, an ethylene-α-olefin copolymer having a small melt index and an ethylene-α-olefin copolymer having a large melt index are used. A composition in which an α-olefin copolymer is mixed to broaden the molecular weight distribution and improve moldability is described. On the other hand, in the latter, ethylene-α-
A polymer composition for heat sealing in which an olefin copolymer and an ethylene-based polymer (such as low-density or high-density polyethylene) are mixed is described.

Further, JP-A-58-160147 discloses a co-extruded multilayer film having heat sealing properties, wherein an inner layer is an ethylene-α-olefin copolymer layer (density 0.92 to 0.94 g / c).
m ³ ) and the core layer is a high-pressure method low-density polyethylene layer (density
0.92~0.93g / cm ³⁾ in and, the multilayer film outer layer is an ethylene -α- olefin copolymer layer (density 0.91~0.93g / cm ³⁾ are described.

Furthermore, for example, according to JP-A-53-54283, a low-melting ethylene-vinyl acetate copolymer layer and a polyethylene layer having a higher melting point and a thickness of 1 to 10 μm are laminated, A multilayer film is described in which a base film such as a nylon layer is laminated on a vinyl acetate copolymer.

However, although the ethylene-α-olefin copolymer layer has good sealing properties, low-temperature sealing properties,
Insufficient sealability and sealing temperature range are still inadequate, and the shortcomings of thin seals have not yet been eliminated. However, the secondary workability was poor and the packaging material was not sufficiently satisfactory. Furthermore, films made containing vinyl acetate have drawbacks such as odors, thin seals and the like.

 The present invention has been made based on the above circumstances.

An object of the present invention is to provide excellent low-temperature sealing properties, foreign substance sealing properties and pinhole resistance, as well as good film-forming and secondary processing properties, such as various foods, beverages, liquid substances such as chemicals, powders, etc. An object of the present invention is to provide a resin laminate that can be suitably used for packaging of granules and the like.

[Means for Solving the Problems] In order to solve the above problems, the present inventors have conducted intensive studies and as a result, have found that a specific resin monolayer film containing a specific ethylene-α-olefin copolymer has been produced. The specific resin laminate used is excellent in low-temperature sealing property, foreign substance sealing property and pinhole resistance, and has good film forming property and secondary processing property, for example, various kinds of foods, beverages, chemicals and the like. The present inventors have found that the present invention can be suitably used for packaging liquids, powders, and the like, and have reached the present invention.

The structure of the invention according to claim 1 has a density of 0.890 to 0.920 g / cm ^3.
The melt index is 2-50g / 10min (190 ℃)
Laminate a base film with a 15-80 μm thick resin monolayer film containing 60% by weight or more of an ethylene-α-olefin copolymer having a tensile modulus of 1,000 to 5,000 kg / cm ^2. According to a second aspect of the present invention, there is provided a resin laminate, wherein the resin single-layer film according to the first aspect and the base film are formed of an adhesive or an anchor coat agent. It is a resin laminate characterized by being laminated via layers.

Hereinafter, the resin laminate according to claims 1 and 2 will be described in detail.

-The resin single-layer film in claim 1-The resin single-layer film in claim 1 is ethylene-α.
-An olefin copolymer is used.

The ethylene-α-olefin copolymer has a density of 0.890 to 0.920 g / cm ³ , preferably 0.900 to 0.915 g / cm ³ , and a melt index of 2 to 50 g / 10 min (19
0 ° C.), preferably 4 to 20 g / 10 minutes (190 ° C.).

The density of the ethylene-α-olefin copolymer is 0.89
If it is less than 0 g / cm ³ , the rigidity of the resin single-layer film using the ethylene-α-olefin copolymer may decrease, or the strength of the heat-sealed portion may decrease. On the other hand, if it exceeds 0.920 g / cm ³ , the low-temperature heat sealability may be poor or the impact strength may be reduced. Further, when the melt index of the ethylene-α-olefin copolymer is less than 2 g / 10 minutes, the melt viscosity is increased and the moldability may be deteriorated. On the other hand, if it exceeds 50 g / 10 minutes, the strength of the heat-sealed portion of the resin single-layer film using the ethylene-α-olefin copolymer decreases, which may cause a decrease in film strength.

Therefore, in the present invention, the ethylene-α-
It is important that the olefin copolymer has a density and a melt index in the above ranges. The melt index of a normal film grade is 2g / 10min (190 ℃)
In contrast, in the present invention, the use of the ethylene-α-olefin copolymer having a melt index of more than 2 g / 10 minutes (190 ° C.) provides an object of the present invention. It is worth noting that

Preferred examples of the ethylene-α-olefin copolymer include a random copolymer of ethylene and an α-olefin having 4 to 10 carbon atoms.

As the α-olefin having 4 to 10 carbon atoms, for example,
Butene-1, pentene-1, hexene-1, 4-methyl-pentene-1, octene-1, nonene-1, decene-
1 and the like.

The α-olefin which can be a comonomer unit of the random copolymer may be used alone or in combination of two or more.

In the present invention, a copolymer having the above-mentioned density and melt index can be appropriately selected and used from the above-mentioned various random copolymers.

Most preferred random copolymers are linear low-density polyethylene (LLDP) containing α-olefin units.
E).

The resin single-layer film in the present invention, the ethylene-
It comprises at least 60% by weight of an α-olefin copolymer.

The resin monolayer film of the present invention may be a low-crystalline or non-crystalline ethylene-α-olefin copolymer and / or a non-crystalline ethylene-α-olefin copolymer in order to improve impact resistance, as long as the heat-sealing property is not impaired. Is 0.900 ~ 0.920g / cm
^The high-pressure low-density polyethylene in the range of ³ may be contained in a proportion of less than 40% by weight based on the whole film.

Examples of the low crystalline or non-crystalline ethylene-α-olefin copolymer include ethylene-propylene rubber (EPR), ethylene-propylene-diene rubber (E
PDM) and a low crystalline ethylene-butene-1 copolymer.

The ethylene-α-olefin copolymer has a tensile modulus in the range of 1,000 to 5,000 kg / cm ² . If the tensile modulus is less than 1,000 kg / cm ² , the film strength of a single-layer film using this copolymer may decrease. On the other hand, if it exceeds 5,000 kg / cm ² , the heat sealability may decrease.

The resin single-layer film in the present invention has a thickness of 15 to
It is 80 μm, preferably 20 to 60 μm. This thickness is 15μ
If it is less than m, the sealing temperature range, strength and the like may be reduced, resulting in poor sealing performance. On the other hand, if it exceeds 80 μm, the film-forming property may be reduced, or a thin seal may be generated.

The resin monolayer film of the present invention may optionally contain various additives together with the ethylene-α-olefin copolymer as long as the present invention is not hindered.

Examples of the additive include a lubricant, an anti-blocking agent, a coloring agent, an antioxidant, a plasticizer, and a heat stabilizer.

The method for forming the resin single-layer film in the present invention is not particularly limited, and a conventionally known method can be appropriately selected and employed. Among them, for example, a T-die method,
A melt extrusion method such as an inflation method is a preferable film forming method. For example, when these film forming methods are adopted, the resin temperature is usually about 180 to 300 ° C., and the cooling temperature is usually about 20 to 80 ° C.

The resin single-layer film in the present invention has a low-temperature sealing property,
It has excellent impurity sealing properties and pinhole resistance, and has good film-forming properties and secondary processing properties, and is suitably used for packaging various liquids such as foods, beverages, and chemicals, and powders. be able to.

-Resin laminate according to claim 2-The resin laminate of the present invention is, for example, as shown in Fig. 1, a resin single-layer film 1 and a base film 2 are formed by bonding an adhesive or an anchor coat agent. It is formed by laminating via a layer 3.

As a material for forming the base film, for example, nylon such as nylon-6, for example, polyester such as polyethylene terephthalate, for example, ethylene-
Examples include stretched or unstretched films or sheets of polyvinyl alcohol such as a saponified product of vinyl acetate copolymer, and polypropylene, polycarbonate films, aluminum foils and other metal foils, and various metal-deposited films.

The base film may have a single-layer structure or a multi-layer structure. Usually, at least one of the various forming materials is, for example, a co-extrusion laminating method.
A film formed by employing various lamination methods such as a dry lamination method, a hot lamination method, a hot melt lamination method, and an extrusion lamination method can be suitably used.

In any case, the thickness of the substrate film is usually 10
100100 μm, preferably 15-80 μm. This thickness is 1
If it is less than 0 μm, the film strength may not be sufficient, and the resin laminate of the present invention may have poor sealing properties. On the other hand, if the thickness exceeds 100 μm, the corresponding effect is not exhibited, and the production cost may be increased, which may not be practical.

The intermediate layer is a layer made of an adhesive or an anchor coating agent.

Examples of the adhesive include vinyl resins such as vinyl acetate, vinyl chloride, and vinylidene chloride resins; cellulose resins such as nitrocellulose, ethyl cellulose, and cellulose acetate; copolymer resins of synthetic rubber and acrylic resin (AB resin). And epoxy resins such as ethylene-vinyl acetate copolymers and ethylene-acrylate copolymers.

Examples of the anchor coating agent include an organotitanium anchor coating agent, a polyethyleneimine anchor coating agent, an isocyanate anchor coating agent, and the like.

The coating amount of the adhesive is usually 1.5~5.0g / m ^2,
The coating amount of the anchor coating agent is usually 0.1 g / m ² or less.

The method for forming the resin laminate of the present invention is not particularly limited as long as it can have a laminated structure, but is preferably, for example, a coextrusion lamination method, a dry lamination method, or the like.
Various lamination methods such as a hot lamination method, a hot melt lamination method, and an extrusion lamination method. For example, when using the extrusion lamination method, the resin temperature is usually 25
It is about 0 to 350 ° C, and the cooling temperature is usually about 10 to 50 ° C.

In laminating the base film and the resin single-layer film, it is preferable that the base film and / or the resin single-layer film be subjected to a surface treatment in advance.

Examples of the surface treatment include a corona discharge treatment, a chromic acid treatment, a flame treatment, a hot air treatment, a surface oxidation treatment such as an ozone / ultraviolet treatment, and a surface unevenness treatment such as sandblasting.

More specifically, the surface of the base film on which the resin monolayer film is to be laminated is subjected to, for example, a corona discharge treatment and then to a treatment with, for example, a general anchor coat agent or to the application of the adhesive. Is preferred. In the case where a film formed in advance as the resin single-layer film is used, it is preferable that a surface of the resin single-layer film on which the base film is to be laminated is subjected to, for example, a corona discharge treatment. Further, for example, when the resin single-layer film is laminated with the base film by using an extrusion laminating method, for example, an ozone treatment is performed on a surface of the resin single-layer film on which the base film is laminated, if necessary. Is preferred.

The resin laminate of the present invention obtained in this way has improved mechanical strength such as rigidity by the base film, and has the resin single-layer film excellent in heat sealability. It can be suitably used as a forming material of a packaging bag which can be suitably used for packaging of granular materials such as drinks, cement, sand and the like, and liquid materials.

[Examples] Next, examples of the present invention and comparative examples will be shown, and the present invention will be described more specifically.

(Examples 1 to 4, Comparative Examples 1 to 5) 65 mmφ using various resins having the properties shown in Table 1 (the tensile elastic modulus in the table conforms to JIS-K-1702).
Melt-kneading with an extruder, multi-manifold multilayer T-
It was supplied to a die (die width 800 mm), extruded at a die temperature of 250 ° C., and cooled with a chill roll at a temperature of 40 ° C. to obtain a resin monolayer film (A) having a thickness of 40 μm.

Next, the chill roll surface of this resin single-layer film was
Corona discharge treatment was performed under the condition of W / m ² / min.

Thereafter, a stretched nylon film (B) having a thickness of 15 μm (G100, manufactured by Idemitsu Petrochemical Co., Ltd.) was dry-laminated on the chill roll surface side of the resin monolayer film subjected to the corona discharge treatment to obtain a resin laminate. .

The adhesive used was an ether-based two-liquid type [AD-300A, manufactured by Toyo Morton Co., Ltd.].

This resin laminate was evaluated for sealing temperature, impurity sealing property I, impurity sealing property II, filling sealing temperature range, and sealing thinness.

 The results are shown in Table 2.

 In addition, each item was evaluated as follows.

Sealing temperature (Idemitsu method): Using a thermal gradient tester manufactured by Toyo Seiki, heat seal layer (A) and heat seal layer (A) are sealed at a pressure of ² kg / cm ² for 1 second, and heat seal strength is obtained. Was 2,000 g / 15 mm, which was taken as the seal temperature.

Contaminant sealability I: Salad oil was filled as a contaminant under the same conditions as the measurement of the seal temperature, and the seal temperature was measured.

Impurity sealability II; Soy sauce was filled as an impurity under the same conditions as the measurement of the seal temperature, and the seal temperature was measured.

Filling seal temperature range: Using a filling and packaging machine (Komatsu Seisakusho, half-fold three-sided seal filling machine, KS324), using a single-roll system, filling the packaging bag (size 60 mm x 70 mm) with soy sauce as a content at a filling speed of 80 bags / Filled in minutes. Load 10 on its filling packaging bag
0 kg was applied, and the range of the sealing temperature at which the durability time was 5 minutes or more was measured.

Seal thinning: A bag was made at a sealing temperature of 145 ° C. under the above-mentioned filling conditions, and the seal thinning was determined by the following formula.

Seal thinning = (thickness of seal portion / total thickness of laminate and raw material) × 100 (%) (Comparative Examples 6 and 7) In Example 1, instead of the resin single-layer film having a thickness of 40 μm, as shown in Table 2, A resin laminate was manufactured in the same manner as in Example 1 except that the resin single-layer film having the indicated thickness was used, and the obtained resin laminate was evaluated.

 The results are shown in Table 2.

(Examples 6 to 8, Comparative Examples 8 to 12) Using various resins having the properties shown in Table 1, 90 mm
Melt kneading with φ extruder, multi-manifold multilayer T
-Feed into a die (die width 800 mm), extrude at a die temperature of 300 ° C. to produce a resin monolayer film (A) having a thickness of 40 μm, and a stretched nylon film 15 μm in thickness [manufactured by Idemitsu Petrochemical Co., Ltd.] , G100], on the laminate surface (anchor coating agent coated surface) side of the base film (B), through a tightening step between a nip roll and a cooling roll (temperature 30 ° C.) to obtain a resin laminate.

As the anchor coating agent, an ester-based two-liquid type [EL364 manufactured by Toyo Morton Co., Ltd.] was used.

With respect to this resin laminate, each item was evaluated in the same manner as in Example 1.

 The results are shown in Table 3.

(Evaluation) From Tables 2 and 3, the resin laminate of the present invention has a lower sealing temperature, is superior in contaminant sealing properties, has a wider sealing temperature range, and has a wider sealing temperature than the resin laminate of the comparative example. It is clear that the object of the present invention has been achieved with a small sealing thinness.

[Effects of the Invention] (1) According to the invention of claim 1, specific ethylene-α
-Since it is made of an olefin copolymer and has a specific thickness, it has excellent heat sealing properties (especially low temperature sealing properties), foreign substance sealing properties and pinhole resistance, as well as film forming properties and secondary processing. The resin monolayer film has good properties and can be suitably used for packaging liquids such as various foods, beverages, and medicines, and powders, and can provide an industrially useful resin monolayer film.

(2) According to the second aspect of the invention, the resin single-layer film according to the first aspect having the above-mentioned excellent features is laminated with the base film having excellent mechanical strength such as rigidity. 1 can provide an industrially useful resin laminate in which mechanical strength such as rigidity is improved without impairing the aforementioned excellent features of the resin single-layer film.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of the resin laminate according to the second aspect. 1 ... single-layer resin film, 2 ... base film, 3 ... intermediate layer made of adhesive or anchor coat agent.

Claims (2)

(57) [Claims] An ethylene-α- having a density of 0.890 to 0.920 g / cm ³ , a melt index of 2 to 50 g / 10 min (190 ° C.) and a tensile modulus of 1,000 to 5,000 kg / cm ^2. Thickness 15-80μ containing 60% by weight or more of olefin copolymer
m, wherein a resin single-layer film and a base film are laminated. 2. A resin laminate comprising the resin single-layer film according to claim 1 and a substrate film laminated via an intermediate layer comprising an adhesive or an anchor coat agent.