JPS5959444A - Cover material - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] The present invention relates to a lid material for easy-open sealed packaging.

Generally, when liquid contents are sealed in a container, the container is filled with the contents, and then the lid and container are heat-sealed.
Seal. In this case, since it is impossible to avoid liquid dripping from the filling nozzle and the like when filling the container, there is a high possibility that the liquid will adhere to the 7-lunge, which is the part of the container to be heat-sealed. Therefore, a sealant with good foreign substance sealing properties is desired. In addition, with current heat sealing, the temperature of the mold for heat sealing varies widely, so a sealant with a wide heat sealing temperature range is desired for easy opening. In other words, the optimal sealant for the lid material is one that has a wide heat-sealing temperature range for easy opening and has good heat-sealability against contaminants.

However, there are currently few lidding materials for polyester containers that provide easy-opening properties, and the only one is one coated with a heat sealant l base material, but this has poor sealing properties against contaminants and is high in solid content such as juice. Not suitable for packaging things.

For this reason, the contaminant heat sealability is good.

In addition, a lid material with a wide heat-sealing temperature range for easy opening is desired.

The present inventor has developed a lid material for sealing containers made of polyester, which has good heat-sealability against contaminants, can be heat-sealed with a strength that makes it easy to open the container, and has a wide heat-sealing temperature range. Surube (research results show that a blend of 20 to 0% by weight of saturated polyester resin and 20 to 0% by weight of polyethylene resin has good heat-sealing property for contaminants in polyester resin containers and strength that makes it easy to open. It is possible to form a seal that can be heat-sealed with #4, and that it is possible to form a flat and thin film by coextruding the blend with other resins, and that it is possible to form a flat and thin film by coextruding the blend with other resins. The sealing layer and the supporting layer that support the lid material laminated on the base material are unsealed by cohesive failure of the sealing layer and delamination between the sealing layer and the supporting layer, so the peeling strength is almost dependent on the heat sealing strength. The present invention was completed on the basis of these findings.

That is, the gist of the present invention is to provide a support layer formed by extrusion molding of one or more layers on a base material and a blend of 20 to 10% by weight of a saturated polyester resin and a polyethylene resin. This lid material is characterized in that a sealing layer extruded together with a support layer is laminated thereon.

The present invention will be explained in detail below with reference to the drawings.
rro.

The first part shows the lid material (4) of the present invention.

Extruded support layer (1) consisting of one layer or multiple layers on base material (3) and saturated polyester resin 20~
A sealing layer (2) is laminated together with the support layer made of a blend of 10% by weight and 20 to 10% by weight of polyethylene resin.

The above-mentioned lid material of the present invention can be effectively utilized for sealing containers made of polyester resin.

The sealing layer of the lid material of the present invention, which is made of a blend of saturated polyester resin and polyethylene resin, exhibits good heat sealability for containers made of polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polybutylene terephthalate. Further, the sealing layer of the lidding material of the present invention exhibits cohesive failure properties, and its adhesive interface is completely fused to the flange surface, so there is no fear of bag breakage and the sealing property against foreign substances is excellent.

Figures ta+ to tel show the process of unsealing the lid material of the present invention heat-sealed to the polyester resin container body; Figure 3+a+ shows the state before opening; FIG. 3 (C1 shows the state after opening.

Immediately after opening, the seal layer (2) and support layer (11
Cohesive failure of the sealing layer (2) occurs toward point B between the layers, then peeling occurs along the gap between the sealing layer (2) and the support layer (11, and then the separation occurs between the sealing layer (2) and the support layer (11).
From the point C between the layers of 1) to the flange (6) and the seal layer (2)
) cohesive failure of the sealing layer (2) occurs towards the point between ), so that the seal can be opened.

As described above, since the lid material of the present invention can be opened by cohesive failure of the sealing layer and peeling between the sealing layer and the support layer, the appearance of the container flange surface after opening is beautiful.

Further, since the unsealing is performed by cohesive failure of the sealing layer and peeling between the sealing layer and the support layer, the peeling strength at the time of unsealing hardly depends on the heat sealing strength.

In packaging containers for foods, etc., peeling does not occur easily during handling during processing and distribution processes after sealing, but easy-open properties must be maintained.Heat sealing has a peel strength of 4,200 to 1 g between films. 00
It is known that Vty is given within the range of bird width. On the other hand, although the heat sealing temperature varies depending on the performance of the sealer and the actual packaging conditions, it is unavoidable that the heat sealing temperature will be 30 to 1]. Therefore, it is required that the fusion strength be maintained within the above-mentioned preferred range over as wide a sealing temperature range as possible. The lid material of the present invention satisfies this requirement.

In the present invention, the saturated polyester resin that is the constituent material of the blend forming the sealing layer includes phthalic acid, isophthalic acid, themphthalic acid, maleic acid, maleic acid derivative, :ff-no:? acids, saturated polybasic acids such as adipic acid and sepastic acid, ethylene glycol, diethylene glycol, glycerin, trimethylolbromine, 12-propylene glycol, 13-butanediol, dipropylene glycol, l'17'-tanediol, /A
Saturated polyester (?4) obtained by ester bonding with polyhydric alcohols such as hexanediol, pentaerythritol, sorbitol, glycerin, neopentyl glycol, and cyclohexane dimetatool.

Since this saturated polyester resin is blended with a polyethylene resin, lθθ˜is.

Desirably, those that melt at °C, for example, acid σ), where the comonomer is phthalic acid, the alcohol comonomers are ethylene glycol and lq-cyclohexane dimetatool, softening point gθ °C, molecule t, zhθ00, density lλ
A polyester saturated polyester resin is preferred. Also, 200”
Molding around C provides the best compatibility and moldability.

On the other hand, the polyethylene resin to be blended with the saturated polyester resin includes high-density polyethylene, medium-density polyethylene, low-density polyethylene, ethene-α-onfin copolymer, ethylene-vinyl acetate copolymer, ionomer, ethylene-ethyl Ethylene content in ethylene copolymers such as acrylate copolymers and saponified ethylene-vinyl acetate copolymers! 0N (Tr% or more polyethylene resin.

Next, in the present invention, the blend ratio of the saturated polyester resin and the polyethylene resin is preferably 20 to 0% by weight of the saturated polyester resin to 20 to 0% by weight of the polyethylene resin, as described above. If the amount of saturated polyester resin is less than 0% by weight, the sealing strength of the polyester ()1 resin container will be weak (on the contrary, if the amount of saturated polyester resin is more than 0% by weight, the seal layer will coagulate) It is completely fused without causing destruction, and does not require easy opening.Also, the appropriate thickness of the sealing layer is /~50μ, especially j~20μ.
μ is optimal. If the seal layer is less than lμ, the contaminant sealing performance will be poor and the seal strength will be unstable, which is undesirable. On the other hand, if it is more than SOμ, a large amount of the blend that makes up the seal layer will remain on the flange after opening, causing damage to the flange. Appearance deteriorates, extreme 7. In case C, the sealing layer remains on the container side, a phenomenon called membrane peeling occurs, making it impossible to take out the contents.

Next, in the present invention, the support layer must be laminated with appropriate adhesive strength to the sealing layer for rj to occur, so the resin for the support layer may be high density polyethylene, medium density polyethylene, low density polyethylene, ethylene- α-olefin cofC fraction and ethylene-vinyl acetate copolymer are suitable.

It is preferable that the thickness of the support layer is 1Oμ or more.

If it is less than IOμ, the support layer will break when the package is opened.

As shown in Figure 1 (film bulging phenomenon occurs).

Next, in the present invention, heat-resistant plastic film, metal foil, paper, etc. can be used as the base material. As the base material, polyethylene terephthalate, stretched nylon, and aluminum foil are most suitable, and polyethylene, polycarbonate, polyethylene, and polyvinyl chloride are also suitable.

The thickness of the base material is small (l and μ) so that it has appropriate rigidity when opened when used as a base material at °C.

Moreover, the optimum thickness of the base material is 0-roμ.

Next, in the present invention, the method of providing the support layer and the sealing layer on the base material is to co-extrude the resin for the support layer and the resin for the sealing layer to form a laminated film, and then dry-laminate the laminated film on the base material. method, or co-extrusion of the resin for the support layer and the resin for the sealing layer in contact with the base material.
Good by any of the stone methods.

As mentioned above, the lid material of the present invention is ideal for use as a filter lid for injection, blow, or sheet molded containers made of polyester, and can also be used in the form of a flat film. You can make it into a drop-lid σ) shape and use it as you like.

From this point of view, the lid layer of the present invention can be used for containers for soft drinks, carbonated drinks, soybean oil, etc., 5 seasonings, detergents, and the like.

Next, the present invention will be specifically explained with reference to examples.

Example 1 An aluminum foil with a thickness of IIOμ was used as a base material, and an anchor material was applied to the surface of the aluminum foil, and then resin i blended with the following saturated polyester resin and polyethylene 7a-t:t was applied.
Lid material 7 was made by co-extruding Oμ and the following polyethylene film Oμ.

(1) The comonomer of the saturated polyester resin acid is ethyl glycol and/or the comonomer of the phthalic alcohol.
, a-cyclohexane dimetatool softening point goo ℃ 1 molecule 2 fuoo, density 1 6 (2) polyethylene density a 923, MT = J, 7 This lid material is an injection plate of polyethylene terephthalate with a thickness of 1 ('XTnbo RT-5L?)
and temperature: lza0℃, pressure;, 20 hours, time; /
Heat sealing was performed under heat sealing conditions of seconds.

After being left to cool, a peel test was performed and it showed good easy opening properties.

EXAMPLE Co-extrusion of the blended resin used in Example 1 and polyethylene resin was carried out using the coin fusion method to obtain a binder resin l.
A laminated film having a layer structure of Oμ/polyethylene 20μ was formed.

Next, the polyethylene layer of this laminated film was laminated to the 7/L/minium surface of the base material (polyester Nokoμ/AI'lOμ) using an incyanate thread adhesive to form a lid material.

When this lid material was subjected to a peel test χ, it showed good easy-opening properties χ.

As described in detail above, the lid material of the present invention not only allows polyester resin containers to be easily opened and sealed, but also has good heat-sealing properties against contaminants, and is heat-sealable for easy-to-open heat-sealing. The temperature head is wide (and the container flange surface will not be damaged after opening, and it can be peeled and opened easily).

[Brief explanation of the drawing]

Figure 1 is a sectional view of the lid material of the present invention, Figure 2 (al~tel
FIG. 3 is a sectional view showing the process of opening the lid, and FIG. (11.Support layer +2)---Seal layer (3)...ψψ...Base material (4)...Lid material Fig. 2 figure

Claims (1)

[Claims] Extruded support layer consisting of one or more layers on the base material and saturated polyester resin - 20 to 50% by weight
A lid material characterized in that a sealing layer formed by extrusion molding is laminated together with the support layer made of a blend of 20% to 50% of a polyethylene resin.