CN111032523B

CN111032523B - Seal, method of dry lamination and method of die cutting

Info

Publication number: CN111032523B
Application number: CN201780093934.6A
Authority: CN
Inventors: 刘纪坚; 李伟康; 王永威; 林振纶; 黄应稳; 黄韵琪
Original assignee: Rolex Gasket Malaysia Ltd
Current assignee: Rolex Gasket Malaysia Ltd
Priority date: 2017-08-16
Filing date: 2017-10-25
Publication date: 2022-02-15
Anticipated expiration: 2037-10-25
Also published as: MY181897A; WO2019035707A1; CN111032523A

Abstract

Our invention is a seal for a container. It is an induction heat seal with a ring-shaped handle 10 to allow easy removal of the seal from the container, which seal comprises a transparent and rigid plastic layer, a PET layer, an aluminium foil layer and a heat sealable layer underneath the aluminium foil. The ring handle 10 allows the seal to be lifted with only one finger so it can be easily removed. For dry lamination, the gravure roll is specially designed to apply glue only on designated areas, so that the force can be transferred more efficiently to remove the seal. For die cutting, the die cutting die is designed to completely cut the outer circumference of the seal, while partially cutting the inner circle to create the ring handle.

Description

Seal, method of dry lamination and method of die cutting

Technical Field

The present invention relates to a seal for a container, and in particular to an induction heat seal having an annular handle to facilitate removal of the seal from the container.

Background

There are currently various types of seals or closures that are designed to seal over the opening of a container. To open the container after sealing, the seal must be broken or peeled off. Such seals or closures are used in various containers, for example, bottles of food, beverages, pharmaceuticals and chemicals. Their main function is to provide a protective element for the product in the container by separating it from the outside environment. In some cases, the seal may also indicate whether the contents have been reconciled. For food products, seals are often used to seal the contents to prevent contamination of the food product and to maintain the freshness of the food product. On the other hand, for chemical products, seals are used to prevent product leakage and spillage. Induction heat seals are one of the most popular types of seals, characterized by sealing performed after undergoing an induction heat sealing process.

In 1960, Palmer, U.S. Pat. No.2,937,418, was of interest because it is clearly an early example of induction heat sealing a seal to the neck of a bottle.

A seal suitable for induction heat sealing around the mouth of a container may comprise a metal foil layer which acts to generate heat during induction heating. The metal foil layer has a heat sealable layer on its underside for adhesion to the bottle mouth and may have a heat resistant layer on its upper side to avoid damage to the lid. Also, in order to open the container, the seal must be broken or peeled off.

The sealing member can be divided into two types according to the bonding property of the sealing member. The first is called "permanent seal", which can be firmly bonded to the neck of the bottle and cannot be peeled off by pulling on the seal itself. The second type is called a "peelable seal" which provides only enough bonding strength to hold the seal and the neck together and can be peeled off the neck by pulling on tabs extending from the outer circumferential side of the seal, which can be folded down along the neck or up on top of its body. The former may have the risk of the tab becoming incorporated into the neck of the bottle, and the latter may require additional effort to insert the seal into the cap.

In 1979, U.S. patent No.4,155,439 to Fletcher et al discusses in detail the production of a seal having a tab folded over the top of a body portion. In this patent, a fully automated machine is introduced to form the seal and assemble it to the container, rather than inserting it into the lid.

In 1986, Carr et al in U.S. Pat. No.4,625,875, incorporated herein by reference, a well-regulated closure. However, it shows a seal provided with a tab folded over the top of its body portion and a cardboard liner placed between the seal and the lid.

U.S. patent No.4,961,986 to Michael p. First, the presence of inwardly folded tabs can affect the seal by induction heating. Induction heating depends on the generation of electrical current and thus on the heat in the foil. The presence of the tabs can locally affect electrical performance and can lead to improper sealing. As discussed in one of the articles "food and drug packaging" issued by Bill Zito at 8 1986, the current tends to follow the actual circumference of the tab. Also, the folded tab may stick to the inside of the lid, requiring a cardboard liner or a silicone liner, etc. In addition, the induction sealing technique relies on the fact that the foil closure is pressed against the neck of the container by the cap. In the presence of folded tabs, uneven pressure may be applied to the seal, which in turn may result in an imperfect seal. Ideally, its thickness should be completely uniform and should be able to be uniformly induction heated so that it can be easily attached to the neck of the bottle by induction heating.

These problems are overcome by a seal with a tab attached at the top, which was first proposed explicitly by Michael p.galda et al in 1990 U.S. patent No.4,961,986. Such a seal comprises: a backsheet, referred to as a sealing film, such as aluminum foil with an underlying sealant layer; and a topsheet, one half of which is bonded to the backsheet and the other half of which is free of adhesive, thereby forming a tab. To remove the seal, the tab is typically grasped between two fingers and pulled laterally and utilizing the bond provided by the adhesive between the top sheet and the sealing film. As highlighted by Galda, if the tab is pulled up or away from the free portion, there may be a tendency for the top layer to separate from the sealing film, depending on the nature of the various materials used and the bond strength of the adhesive layer.

To produce the top tabbed seal claimed by Galda et al in U.S. patent nos. 4,961,481 and 5,433,992, the adhesive used to bond the top layer and the sealing film did not extend across the entire width of the strip, extending only along the left side of the elongated strip, with no adhesive along the extension of the right side of the elongated strip. In practice, the elongate strip will be produced as part of a wider strip comprising several elongate strips, as shown in fig. 1 or suggested by others in U.S. Pat. nos. 5,702,015, 6,866,926B1, 6,902,075B2, 8,308,003B2, 8,455,071B2, to apply the full width of adhesive on the top layer and feed an additional number of small strips, such as a PET film with gaps between each other sandwiched by the top layer and a sealing film, as shown in fig. 2. Once the elongate strip is formed, each circular seal is die cut, typically from the center of the elongate strip.

In short, there are two popular tab type induction heat seals: side tab seals and top tab seals. As emphasized by Michael p. galda et al in U.S. patent No.4,961,986, the side tab seal suffers from some problem of imperfect sealing. These problems were overcome by the first introduction of a top tab seal in U.S. patent No.4,961,986 to Michael p. However, top tab seals have a limited pull angle and require two fingers to pull them apart.

Accordingly, there is a need for an improved and reliable container seal, particularly having a hard tab that allows the seal to be easily removed from the container.

Disclosure of Invention

The present invention provides a novel seal. Most particularly, the present invention provides a closure seal having a peripheral annular tab which enables the seal to be easily removed from the bottle.

According to the present invention, the sealing member is formed of a laminate material including the following co-epitaxial layers:

a) a plastic (PP, PE, PET, nylon, etc.) top layer;

b) PE/PET adhesive layer

c) PET plastic layer

d) PET/foil layer

e) Aluminum foil

f) Foil/heat seal adhesive layer

g) Heat sealing layer

The PE film was partially adhered to the upper surface of the PET plastic layer and, after die cutting, would form an annular handle. The handle facilitates removal of the seal. The function of the aluminium foil and the PET film is to provide a gas-tight protection for the contents of the container. On the other hand, the function of the sealing medium is to fix the entire sealing member to the bottle after undergoing an induction heat sealing process. The adhesive holds all of these layers together to become the composite.

The invention further provides a method for producing a seal of this type. Preferably, the method comprises the steps of: bonding the layers together using a dry lamination process using a gravure technique and applying a partial bond to the loop grip layer; inserting marks on the laminated piece in the dry laminating process, and carrying out targeted stamping by using the marks; by performing full cuts and partial cuts, the laminate is die cut to the desired design.

The greatest advantage of the present invention is to provide an annular handle that can easily remove a seal from a container without disrupting the induction heat sealing process. Conventional inwardly folded tabs can interfere with sealing. On the other hand, conventional top tab designs have a limited pull angle and require two fingers to pull them apart. Most importantly, it may be difficult for an end user to remove a conventional top tab seal when wetting their hands, as conventional top tab designs require friction to function. The present invention can eliminate all the above problems. It has no inwardly folded tabs, does not interfere with the sealing process, and the ring handle ensures easy removal of the seal. The loop handle of the present invention enables removal of the seal with one finger.

Drawings

The invention is further illustrated in the following figures, in which:

fig. 1 and 2 show the prior art.

Fig. 3 is a cross-sectional view of the present invention.

Fig. 4 contains 2D diagrams showing how the refrigerator tab seal is sealed to the container after the induction heat sealing process and 3D diagrams showing how the seal can be removed with only one finger.

Figure 5 is a detail of the present invention showing the glue area and die cut location.

Figure 6 shows how the dry lamination process uses a gravure press to apply glue to the designated areas.

Fig. 7 shows the mixing of fillers into the adhesive.

Fig. 8 is a diagram of a die cut mold for producing the present invention.

FIG. 9 shows how the mark sensor on the die cutting machine reads the mark to ensure accurate punching.

Detailed Description

As shown in fig. 3, the present invention comprises a combination of a plastic top layer 1 made of one of PE, PP, PET and nylon with a loop handle, a PET layer 2, an aluminium foil 3, a heat sealing layer 4 and

adhesive layers

5, 6, 7 to hold all the layers together to form a composite material. The composite material will be cut completely along a circle to form the seal and the top layer 1 will be partially cut to form the handle 10. The PET layer served as a buffer layer to ensure 3100% of the aluminum foil was intact to protect the contents of the container.

As shown in fig. 4, after the induction heat sealing process, the seal will adhere to the mouth of the container 8 to protect the contents of the container, as described above. After removing the lid 9, we can see the seal with its peripheral annular handle 10. The loop grip 10 is not glued to the underlying layer 2, so that it can be lifted with only one finger. The loop handle is made of a thick, transparent and rigid plastic film to minimize the elongation of the handle when pulled. In addition, the optimal pull angle 11 of the present invention is much wider than conventional top tab designs. Due to the design of the handle 10, the present invention can be opened at an optimal pull angle 11 from 10 degrees to 135 degrees. Conventional top tab seals, on the other hand, only allow the seal to be opened at a very limited angle, otherwise there is a risk of breaking and delaminating the tabs.

Fig. 5 shows a detailed design of the present invention. The design of the seal can be divided into two parts: the shape of the gluing zone 12 and the internal mould tangent 13. The glued area is of a partial ring design with a parabolic curve 14 at its end. The shape of the parabolic curve is to ensure that the force is concentrated at a single point 15 for easy removal of the seal. The die cut 13, on the other hand, is intended to ensure that the handle 10 is separated from the glued area 12 between the top layer 1 and the second layer 2, so that the handle can be lifted.

The manufacturing process of the present invention can be divided into two parts: a dry lamination process and a die cutting process. The dry lamination process uses a gravure press to bond all the layers together and a special gravure press 16 as shown in figure 6 to apply the glue to the designated areas. In order to impart a distinct colour to the seal and to create indicia 17 to aid in later targeted stamping, a coloured filler is added to the adhesive between the top layer and the second layer during lamination, as shown in figure 7.

During the die cutting process, the die cutting dies shown in fig. 8 are equipped with cutters of different heights. The outer cutter 18 is slightly higher than the inner cutter 19; a full cut is made on the composite liner to form a seal and a half cut is made along the inner mold cut line 13 to form a handle.

The indicia 17 formed during the dry lamination process is important during the die cutting process. As shown in fig. 9, the indicia sensor 20 on the die cutter will read the colored indicia 17 and direct the die cutter to make a cut at the correct location.

Claims

1. A seal for a container having a loop-shaped handle and formed from a laminate, the seal comprising:

a. hard transparent plastic top layer

b. Plastic/plastic adhesive layer

PET plastic layer

PET/foil adhesive layer

e. Aluminum foil

f. Foil/heat seal adhesive layer

g. Heat sealing layer

Wherein the plastic/plastic adhesive layer bonds the plastic top layer to the PET plastic layer over a designated glue joint area (12), wherein the PET/foil adhesive layer bonds the PET plastic layer to the aluminum foil over the entire area of the facing surfaces of the PET plastic layer and the aluminum foil, the foil/heat seal adhesive layer bonds the aluminum foil to the heat seal layer over the entire area of the facing surfaces of the aluminum foil and the heat seal layer,

wherein the plastic/plastic adhesive layer does not bond the entire plastic top layer to the PET plastic layer to allow an annular handle to be lifted from the remainder of the seal,

wherein the region of the loop-shaped grip is characterized by a parabolic curve (14) that concentrates most of the pulling force to a single point (15).

2. The seal according to claim 1, wherein an annular handle (10) of the seal follows the periphery of the seal, which can be lifted with one finger to enable easy removal of the seal.

3. The seal according to claim 1, wherein the plastic top layer is glued to the PET plastic layer over most of the facing surface, except in the area of the ring handle (10).

4. A method of dry lamination using a gravure impression roller wherein

a. Glue is applied only to the designated area;

b. a filler mixed with a binder to impart a unique color to the seal of any one of claims 1-3;

c. a mark is generated for reading by a mark sensor.

5. A die cutting method wherein

a. A marking sensor uses markings from the dry laminate to guide a die cutter to cut at the correct location to produce a seal according to any one of claims 1-3 from a laminate or roll;

b. the inner cutter, which cuts through only the top layer of plastic to form the handle, is shorter than the outer cutter, which cuts through all layers to form the seal.