JP3538433B2 - Multilayer sealant film for lamination - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer sealant film for lamination having good slipperiness and blocking resistance of a sealant surface after lamination using an ethylene-.alpha.-olefin copolymer.

[0002]

2. Description of the Related Art Usually, packaging of food, sundries, industrial goods, and the like includes a base film such as a biaxially stretched polyamide film, polyester film, or polypropylene film in view of strength, function, appearance, and the like. Laminated films obtained by laminating a sealant film made of a polyolefin-based resin such as an ethylene-α-olefin copolymer with a dry laminating method, a sand laminating method, an extrusion laminating method or the like are widely used.

[0003] A slip agent is added to the sealant film used for the above-mentioned laminate film in order to impart an appropriate slip property. After lamination, the slip agent is added to an adhesive or other base material layer with the passage of time. Since the concentration of the slip agent on the surface of the sealant decreases due to migration, the slip property and blocking resistance of the obtained laminated film deteriorate, and troubles occur in the bag making process, the filling process of the wrapped material, and the like. There was a problem. In particular, it has been known that this problem appears remarkably in a dry laminate using a polyether-based urethane adhesive. As a countermeasure, powder such as corn starch is applied to the surface of the sealant to impart slipperiness and blocking resistance. However, this method not only leads to an increase in cost such as an increase in the number of steps, but also has a problem that powder adhering to the surface of the sealant is mixed into the package.

Japanese Unexamined Patent Publication (Kokai) No. 3-172328 discloses a method of blending an unsaturated fatty acid bisamide and an unsaturated fatty acid amide having a melting point of 65 ° C. or more and 90 ° C. or less with a polyethylene resin as a slipping agent. A polyethylene-based sealant film having good properties has been proposed. However, when the slip agent is added to such an extent that the effect of the present invention can be exerted, when the obtained sealant film is aged for several months and then dry-laminated, the unsaturated fatty acid bisamide bleeds out on the bonding surface and the bonding strength is reduced. There was a problem that it became insufficient.
Therefore, it was not practical because the long-term stock of the sealant film could not be obtained.

[0005]

DISCLOSURE OF THE INVENTION The present invention provides a sealant film having good slipperiness and blocking resistance after lamination without applying powder such as corn starch even after long-term stocking of the sealant film, and An object of the present invention is to provide a sealant film for lamination that provides sufficient adhesive strength.

[0006]

According to the present invention, in a sealant film for lamination comprising an ethylene-α-olefin copolymer, one surface layer (layer A) has a melting point of 10%.
It contains 0.04 to 0.30 wt% of a slip agent consisting of a slip agent L having a melting point of 100 ° C. or higher and a slip agent L having a melting point of 100 ° C. or higher and 0.1 wt% or more of an antiblocking agent.
Layer) having a melting point of less than 100 ° C. with a slip agent L of 0.02 to 0.25 wt%.
The multilayer sealant film for laminations characterized by containing is provided.

In other words, in the present invention, the lamination sealant film is multi-layered, and a slip agent and an anti-blocking agent having different compositions are used for the respective surface layers. It has been found that the adhesive strength does not decrease even after long-term stock, and the present invention has been reached.

The ethylene-α-olefin copolymer used in the present invention is not particularly limited, but has a density of 0.90.
~ 0.94 g / cm ³ , melt index 0.5 ~ 5.0 g / 10min
Are preferable, and the α-olefin has 4 carbon atoms.
~ 8, such as butene-1, hexene-1,4-
Methylpentene-1, octene-1 and the like. In addition, low-density polyethylene may be added in an amount of about 10 to 30% by weight to improve moldability and transparency to the extent that the properties of the ethylene-α-olefin copolymer are not impaired.

The slip agent is not particularly limited as long as it falls within the scope of the present invention. Examples of the slip agent L having a melting point of less than 100 ° C. include oleic amide and erucamide, and the slip agent H having a melting point of 100 ° C. or more. Examples include behenic acid amide and hexamethylene bisoleic acid amide.

Examples of the anti-blocking agent include silica, zeolite, and talc. The amount of the anti-blocking agent depends on the thickness of one surface layer (layer A) serving as the sealant surface to which the anti-blocking agent is added. It is preferable to add so as to be not more than wt% from the viewpoint of preventing deterioration of transparency.

In the present invention, one surface layer (layer A) serving as a sealant surface contains a slip agent L having a melting point of less than 100.degree. C. and a slip agent H having a melting point of 100.degree. 0.1 wt% or more of antiblocking agent is blended. In this, the compounding amount of the slip agent H is 0.02wt%
If the amount is less than the above, slipperiness and blocking resistance after lamination are insufficient, and if the amount exceeds 0.25 wt%, the amount of the slip agent H transferred to the B layer during storage increases, and the adhesive strength decreases. If the compounding amount of the agent L is less than 0.02 wt%, the slipperiness is insufficient, and if it exceeds 0.25 wt%, the slipperiness before lamination becomes excessive, resulting in a winding deviation of the sealant film or a bleeding slip agent. It is not preferable because troubles such as adhesion of white powder to a roll or the like occur in a process before lamination. Therefore, the slip agent L:
The weight ratio of the slip agent H is preferably in the range of 20 to 80:80 to 20, and the total amount of the slip agent in one surface layer (A layer) is preferably 0.04 to 0.30 wt%. .

On the other hand, the other surface layer (B
The layer) contains 0.02 to 0.25% by weight of the slip agent L. If the slip agent H is added to the layer B, the adhesive strength is remarkably reduced when laminating after curing the sealant film, which is not preferable. If the amount of the slip agent L is less than 0.02% by weight, the slipperiness is insufficient, and 0.25% by weight.
%, The slipperiness before lamination becomes excessive, and the winding of the sealant film is displaced, and troubles in the process before lamination such as adhesion of white powder to a roll or the like due to a bleed slip agent are not preferred.

Furthermore, it is also possible to provide an intermediate layer between one surface layer (layer A) and the other surface layer (layer B) to which an anti-blocking agent which causes deterioration of transparency is not added. It is preferable to add the slip agent L and the slip agent H to the intermediate layer in the same amount as the layer A in order to make the bleed out of the slip agent uniform. In this case, it is preferable to reduce the thickness of the layer A containing the anti-blocking agent as much as possible in order to maintain transparency.

The method for forming a film in the present invention is not particularly limited, and examples thereof include multi-layer inflation extrusion molding and multi-layer T-die extrusion molding. The molding thickness is preferably 30 to 90 μm.

[0015]

EXAMPLES The sealant film for lamination of the present invention will be described with reference to the following examples. The evaluation was performed by the following method. <Slidability> After lamination, aging was performed in a 40 ° C. atmosphere for 2 days, and the slipperiness between the sealant surfaces / sealant surfaces of the laminate film was measured in accordance with ASTM D1894. <Haze (Transparency)> After lamination, the laminate film was aged in an atmosphere of 40 ° C. for 2 days, and was measured in accordance with ASTM D 1003. <Blocking resistance> After lamination, 2
Laminated film aged for one day is superimposed on the sealant surface at 40 ° C with a load of 10 kg / 25 cm ² applied.
After being left in an atmosphere of -70% RH for 15 days, the films were opened by hand to evaluate the quality. ：: Good openability ×: Poor openability <Adhesion strength> After aging the sealant film for one month and in a 40 ° C atmosphere for 2 months and 6 months, dry laminating with the base film, and after lamination And then aged for 2 days at 40 ° C.
After cutting to a width of 15 mm, the T peel strength between the base film and the sealant film was measured and evaluated at a peel speed of 100 mm / min.

The following materials were used as raw materials. LL1: Ethylene-α-olefin copolymer (MI = 2.1 g / 1
0 min, density 0.935 g / cm ³ ) LL2: ethylene-α-olefin copolymer (MI = 2.1 g / 1
0 min, density 0.920 g / cm ³ ) LD: low density polyethylene (MI = 1.5 g / 10 min, density 0.92)
2 g / cm ³ ) SA1: Oleic acid amide (mp = 76 ° C.) SA2: Erucic acid amide (mp = 84 ° C.) SA3: Hexamethylenebisoleic acid amide (mp = 118 ° C.)
℃) ABA: silica (average particle size 5μ)

Examples 1 to 3 As shown in Table 1, a predetermined amount of an ethylene-α-olefin copolymer, a slip agent and an antiblocking agent were blended, and a three-layer inflation molding machine having a die diameter of 300 mm was used. After performing multilayer inflation extrusion at a blow ratio of 1.7, the surface tension of the B layer, which is the bonding surface, is 48 dyne / cm.
Corona discharge treatment was performed to obtain a sealant film for lamination having a thickness of 40 to 80 μm.

Example 4 As shown in Table 1, a predetermined amount of an ethylene-α-olefin copolymer, a slip agent and an antiblocking agent were blended, and a multilayer T-die molding machine having a die width of 1200 mm was used.
After the die extrusion, the surface of the layer B serving as an adhesive surface was subjected to corona discharge treatment so that the surface tension became 48 dyne / cm, to obtain a sealant film for lamination having a thickness of 60 µm.

Comparative Examples 1 to 3 As shown in Table 1, a predetermined amount of an ethylene-α-olefin copolymer, a slip agent and an antiblocking agent were blended, and the blow ratio was determined using an inflation molding machine having a die diameter of 300 mm. After performing inflation molding at 1.7, the surface on the bonding surface side was subjected to corona discharge treatment so that the surface tension became 48 dyne / cm, to obtain a sealant film for lamination having a thickness of 60 µm.

[0020]

[Table 1]

APPLICATION EXAMPLE One day after forming the sealant films for lamination obtained in Examples 1 to 4 and Comparative Examples 1 to 3, a dry lamination method was performed using a 15 μ biaxially stretched polyamide film and a polyether adhesive. Lamination was performed, but the slipperiness before lamination was good even when any of the sealant films was used. Table 2 shows the properties of the obtained laminate film. As is clear from Table 2, the sealant film according to the present invention did not show a decrease in adhesive strength even when dry-laminated after being subjected to severe long-term aging of 6 months in an atmosphere of 40 ° C. Was good in both slipperiness and blocking resistance.

[0022]

[Table 2]

[0023]

[Effect] The sealant film for lamination of the present invention comprises:
Even if lamination is performed after long-term stocking, sufficient adhesive strength can be obtained, and without applying powder such as corn starch after lamination, it is possible to obtain a laminated product excellent in slipperiness and blocking resistance, so it is necessary to apply powder. Not only can cost and time be reduced, but it can also be used for applications where powder could not be used in the past.

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁷ Identification symbol FI // C08L 23/08 C08L 23/08 (56) References JP-A-3-172328 (JP, A) JP-A-64-43546 (JP, A) JP-A-61-281143 (JP, A) JP-A-62-265336 (JP, A) JP-A-2-127573 (JP, A) JP-A-3-281341 (JP, A) JP-A-57-6764 (JP, A) JP-A-61-169245 (JP, A) JP-A-4-62050 (JP, A) JP-A-59-62148 (JP, A) (58) Int.Cl. ⁷ , DB name) B32B 27/32 C08J 5/18 C09K 3/10

Claims (1)

(57) [Claims] In a sealant film for lamination comprising an ethylene-α-olefin copolymer, one surface layer (A layer) has a slip agent L having a melting point of less than 100 ° C. and a melting point.
Slip agent consisting of slip agent H at 100 ° C or higher 0.04 to 0.
Contains 30wt% and 0.1wt% or more of anti-blocking agent,
A multilayer sealant film for lamination, characterized in that the other surface layer (layer B) contains 0.02 to 0.25 wt% of a slip agent L having a melting point of less than 100 ° C.