JP6793662B2 - Tube container with top sealant - Google Patents

Description

The present invention relates to a top sealing material for a tube container.

The lid material of the container for storing food, medicine, cosmetics, etc. is desired to be strongly adhered to the container in order to maintain high airtightness and prevent opening during transportation, whereas as much as possible. It is required to be easy to open.

An example of such a container is a tube container. As a lid material (top seal material) for the mouth of the tube container, for example, Patent Document 1 discloses a top seal material in which polyethylene terephthalate resin / aluminum foil / acrylonitrile resin is laminated in this order.

Patent Document 2 discloses a top sealing material in which a PET film / silicon oxide vapor deposition film / adhesive layer / printing layer / PET film / adhesive layer / polyethylene-based easy-peel resin film are laminated in this order. The silicon oxide vapor-deposited film, which is a barrier layer, improves airtightness, storage stability of the contents, etc., and the easy-peel resin is used for the sealant layer to improve the openability.

The easy peel resin is obtained by blending other incompatible or partially compatible thermoplastic resins with the resin, and generally, fine spherical domain phases (islands) are matrix phases (sea). It forms a sea-island structure dispersed in.

Patent Document 2 discloses that, for example, a resin obtained by blending low-density polyethylene with polybutene-1 and a polystyrene-based resin is used as the easy peeling resin.

Patent Document 3 discloses a top sealing material laminated in the order of PET film / printing layer / adhesive layer / silicon oxide vapor deposition film / PET film / adhesive layer / polyethylene-based easy-peel resin film. Here, it is disclosed that a resin obtained by blending a polyethylene resin with a polystyrene resin is used as the easy peeling resin.

Japanese Unexamined Patent Publication No. 10-1149 Japanese Unexamined Patent Publication No. 2005-8246 Japanese Unexamined Patent Publication No. 2006-27631

In the top sealing material of the prior art, it is assumed that the sealing surface of the container mouth is composed of a single layer. The problem when the sealing surface of the container mouth is composed of a plurality of layers, particularly the problem when the sealing surface is composed of a plurality of layers made of materials having different softening points, is not mentioned in the prior art.

Examples of the container in which the sealing surface of the container mouth is composed of a plurality of layers include a multilayer blow tube in which polyethylene (PE) / ethylene-vinyl alcohol copolymer (EVOH) / polyethylene (PE) are laminated in this order. Be done.

In such a tube container, when the conditions for sealing the top sealing material are stronger than the optimum conditions, for example, when the sealing temperature is high, the sealing time is long, the sealing pressure is high, etc., the tube container mouth Of the plurality of layers of the portion, the layer of the material having the low softening point may be softened, and the layer of the material having the high softening point may not be softened and may maintain the same shape. Therefore, the layer of the material at the high softening point may penetrate the sealant layer of the top sealant, whereby the contents may invade between the base material layer / the sealant layer and cause delamination in the top sealant.

Further, in the top sealing material using an easy peeling resin, when a resin having a high softening point is used as a matrix phase (sea) and a resin having a low softening point is used as a domain phase (island), for example, Patent Document 3 As described, when a blended resin in which a polyethylene resin (sea), which is a high softening point material, is dispersed with a polystyrene resin (islands), which is a low softening point material, is used as an easy peeling resin, opening strength There may be problems such as variations in the plastic and the ease of opening. It is considered that this is because when the sealing temperature is too low, pseudo-adhesion occurs between the polystyrene constituting the island portion and the polyethylene at the container mouth. It is also considered that when the sealing temperature is too high, the sea-island structure of the sealant layer is broken.

The present invention has been made in the background of the problems of the prior art, and even if the sealing surface of the container mouth is made of a plurality of different materials having different softening points, stable opening strength and easy opening strength are achieved. It is an object of the present invention to provide a top sealing material for a tube container that realizes openability.

The above problems can be solved by the present invention having the following aspects.

<< Aspect 1 >>
It is a top sealing material for sealing the mouth of the tube container.
On the surface where the mouth of the tube container is sealed, a cross section of two or more resin layers containing resins having different softening points is exposed, and one of the two or more resin layers is another resin. Contains a low softening point resin that has a lower softening point than the layer resin,
The top sealant has at least a base material layer as the outermost layer and a sealant layer as the innermost layer.
The sealant layer is composed of a blended resin having a sea-island structure in which two or more kinds of resins are blended, and the resin constituting the sea portion of the sea-island structure is a heat-sealed resin with a low softening point at the mouth. The resin that constitutes the island portion of the sea island structure is a resin that has a higher softening point than the resin that constitutes the sea portion of the sea island structure and the low softening point resin of the mouth portion.
Top sealant for tube containers.
<< Aspect 2 >>
The tube container is composed of a laminate of two or more resin layers containing resins having different softening points, and the two or more resin layers of the laminate are sealed on the surface where the mouth portion of the tube container is sealed. The top sealing material for a tube container according to the first aspect, which is a blow tube container whose cross section is exposed.
<< Aspect 3 >>
The top seal for a tube container according to aspect 1 or 2, wherein the softening point of the resin constituting the sea portion of the sea island structure of the sealant layer is within ± 15 ° C. of the softening point of the low softening point resin of the mouth portion. Material.
<< Aspect 4 >>
The top for a tube container according to any one of aspects 1 to 3, wherein the softening point of the resin constituting the sea portion of the sea island structure of the sealant layer is lower than the softening point of the low softening point resin of the mouth portion. Sealant.
<< Aspect 5 >>
The low softening point resin at the mouth is a polyethylene resin, the resin constituting the sea portion of the sea island structure of the sealant layer is a polyethylene resin, and the resin constituting the island portion of the sea island structure is polypropylene. The top sealing material for a tube container according to any one of aspects 1 to 4, which is a based resin.
<< Aspect 6 >>
It is a top sealing material for sealing the mouth of the tube container.
On the surface where the mouth of the tube container is sealed, a cross section of two or more resin layers containing resins having different softening points is exposed, and one of the two or more resin layers is another resin. Contains a low softening point resin that has a lower softening point than the layer resin,
The top sealant has at least a base material layer as the outermost layer and a sealant layer as the innermost layer.
The sealant layer is composed of a blended resin having a sea-island structure in which two or more kinds of resins are blended, and the sea portion of the sea-island structure contains a polyethylene-based resin having a softening point of 90 ° C. or higher and 130 ° C. or lower. The island portion of the sea-island structure contains a polypropylene-based resin having a softening point of 110 ° C. or higher and 170 ° C. or lower and higher than the softening point of the polyethylene-based resin of the sea portion.
Top sealant for tube containers.
<< Aspect 7 >>
The top sealing material for a tube container according to any one of aspects 1 to 6, which has a barrier layer between the base material layer and the sealant layer.
<< Aspect 8 >>
The top sealing material according to any one of aspects 1 to 7, and a tube container whose mouth is sealed with the top sealing material, and which is softened on the surface where the mouth of the tube container is sealed. A low softening point resin in which the cross section of two or more resin layers containing resins having different points is exposed, and one of the two or more resin layers has a lower softening point than the resin of the other resin layer. Tube container with top sealant, including tube container.
<< Aspect 9 >>
The tube container with a top sealing material according to aspect 8, wherein the low softening point resin at the mouth is a polyethylene resin having a softening point of 90 ° C. or higher and 130 ° C. or lower.
<< Aspect 10 >>
The tube container with a top sealant according to aspect 8 or 9, wherein the end is open so that the contents can be filled.
<< Aspect 11 >>
The tube container with a top sealant according to aspect 8 or 9, which is filled with the contents.

According to the present invention, a top seal for a tube container that realizes stable opening strength and easy opening even if the sealing surface of the container mouth is made of a plurality of different materials having different softening points. The material can be provided.

It is sectional drawing which shows the laminated structure of the top sealing material of this invention. It is sectional drawing which shows an example of the tube container which attached the top sealing material of this invention to the sealing surface of the tube container mouth part. It is the schematic of the layer structure of the tube container of this invention.

<Top seal material>
The top sealing material for a tube container of the present invention is used to seal the mouth of a tube container. For example, as shown in FIG. 2A, the top sealing material 10 for a tube container of the present invention seals the mouth 40 of the tube container and stores the contents 50 such as food, pharmaceuticals, cosmetics, or industrial products. It enhances stability and the like. Reference numeral 20 in FIG. 2 indicates a cap to be attached to the mouth of the tube container.

As shown in FIG. 2 (b), the mouth 40 of the tube container having an open end (open end 60) is pre-sealed with the tube container top sealing material 10 of the present invention, and then A tube container containing contents may be obtained by closing the open end 60 of the tube container after filling the tube container with the contents from the open end 60. Further, as shown in FIG. 2C, after filling the content 50 from the tube container mouth 40 whose end is closed, the mouth 40 is sealed with the tube container top sealing material 10 of the present invention. You may obtain a tube container containing the contents.

In one embodiment, the tube container top sealant of the present invention has at least a base material layer as the outermost layer and a sealant layer as the innermost layer. Further, a barrier layer may be further provided between the base material layer and the sealant layer, and a second base material layer may be further provided between the barrier layer and the sealant layer. Further, an adhesive layer may be provided between any two layers of the base material layer, the optional barrier layer, the optional second base material layer, and the sealant layer.

In one embodiment, the sealant layer of the top sealing material for a tube container of the present invention is composed of a blended resin having a sea-island structure in which two or more kinds of resins are blended, and is a resin constituting the sea portion of the sea-island structure. However, it is a resin that is heat-sealed with the low softening point resin of the container mouth, and the resin that constitutes the island part of the sea island structure is more than the resin that constitutes the sea part of the sea island structure and the low softening point resin of the container mouth part. Is also a resin with a high softening point.

For example, as illustrated in FIG. 1, the top sealing material 10 for a tube container of the present invention has a base material layer 1a, an optional barrier layer 2, an optional second base material layer 1b, and a sealant layer 3. The sealant layer 3 is composed of a blended resin of the resin 3a constituting the sea portion of the sea island structure and the resin 3b constituting the island portion of the sea island structure.

In one embodiment, in the tube container sealed by the top sealing material of the present invention, a cross section of two or more resin layers containing resins having different softening points is exposed on the surface where the mouth of the tube container is sealed. It is a tube container. And in one embodiment, one of the two or more resin layers comprises a low softening point resin having a lower softening point than the resin of the other resin layer.

In one embodiment, the tube container sealed by the top sealing material of the present invention is composed of a laminate of two or more resin layers containing resins having different softening points, and the mouth of the tube container is sealed. It may be a blow tube container in which the cross section of two or more resin layers is exposed on the surface to be formed.

For example, as illustrated in FIG. 3, the low softening point resin layer 4a and the other resin layer 4b are exposed on the sealing surface of the tube container mouth portion 40. In one embodiment, the top sealing material 10 for a tube container of the present invention includes a base material layer 1a, an optional barrier layer 2, an optional second base material layer 1b, and a sealant layer 3, and the tube container mouth portion. It can be used by being bonded to the sealing surface of 40 via the surface of the sealant layer 3.

Although not limited to theory, the top sealing material for tube containers of the present invention was heated at a temperature at which the low softening point resin at the mouth of the tube container and the resin constituting the sea portion of the sealant layer of the top sealing material softened. Even so, since the resin constituting the island portion does not soften, pseudo-adhesion between the resin constituting the island portion and the tube container mouth does not occur. Therefore, the low softening point resin at the tube container mouth and the sealant of the top sealing material It is considered that the resin constituting the sea portion of the layer can be stably welded.

Therefore, it is not necessary to raise the sealing temperature, for example, in order to increase the sealing strength. Therefore, the top sealing material for the tube container of the present invention is stably welded to the mouth of the tube container even at a low temperature. It is thought that it can be made to. Further, even if the sealing condition is stronger than the optimum condition such as a high sealing temperature, it is possible to prevent problems such as breakage of the sea-island structure of the sealant layer, variation in opening strength, and deterioration of easy opening. Conceivable.

Further, a resin layer containing a high softening point resin that does not melt when the tube container mouth is heat-sealed penetrates the sealant layer of the top sealant, and the contents penetrate into the base material layer / sealant layer. It is considered that the delamination of the top sealing material is less likely to occur.

(Base material layer and optional second base material layer)
The base material layer is a layer used to retain the strength of the top sealing material for tube containers, heat resistance and processability at the time of sealing, and elasticity required for opening properties. In order to further improve the above performance, it is preferable to laminate a second base material layer between the optional barrier layer and the sealant layer in addition to the outermost base material layer.

The resin used for the base material layer and the optional second base material layer is not particularly limited as long as it gives the above performance, but for example, a polyester resin such as polyethylene terephthalate or a polyamide resin (for example, nylon). , Nylon 6, Nylon 6, 6, Nylon MXD6), polyolefin-based resins (polyethylene-based resin, polypropylene-based resin, cyclic polyolefin resin) and the like, and mixtures thereof. In order to further improve heat resistance and impact resistance, it is preferable to use various resin films as described above that have been subjected to biaxial stretching processing.

In the present specification, the polyethylene-based resin is a resin containing 30 mol% or more, 40 mol% or more, 50 mol% or more, 60 mol% or more, 70 mol% or more, or 80 mol% or more of repeating units of ethylene groups in the main chain of the polymer. For example, low density polyethylene (LDPE), linear low density polyethylene (LLDPE), medium density polyethylene (MDPE), high density polyethylene (HDPE), ethylene-acrylic acid copolymer (EAA), ethylene-methacryl. Acid copolymer (EMAA), ethylene-ethyl acrylate copolymer (EEA), ethylene-methyl acrylate copolymer (EMA), ethylene vinyl acetate copolymer (EVA), carboxylic acid-modified polyethylene, carboxylic acid-modified ethylene vinyl It is selected from the group consisting of acetate copolymers, derivatives thereof, and mixtures thereof.

In the present specification, the polypropylene-based resin is a resin containing 30 mol% or more, 40 mol% or more, 50 mol% or more, 60 mol% or more, 70 mol% or more, or 80 mol% or more of repeating units of propylene groups in the main chain of the polymer. For example, polypropylene (PP) homopolymers, random polypropylene (random PP), block polypropylene (block PP), chlorinated polypropylene, carboxylic acid-modified polypropylene, derivatives thereof, and mixtures thereof.

The above-mentioned base material layer and an optional second base material layer can be provided with a desired print pattern layer composed of, for example, characters, figures, patterns, symbols, etc., and the print pattern layer is, for example, It can be provided by a printing method such as offset printing, gravure printing, flexo printing, letterpress printing, etc. using a normal ink composition.

The thickness of the base material layer and the optional second base material layer is preferably 5 μm or more, 10 μm or more, 15 μm or more, 20 μm or more, or 30 μm or more, and more preferably 200 μm or less, 100 μm or less, or 50 μm or less. The thickness of the base material layer and the optional second base material layer can be selected according to desired performance such as heat resistance at the time of sealing, processability, and opening property.

(Barrier layer)
The barrier layer is a layer optionally used to impart moisture and gas barrier properties. Examples of the barrier layer include an aluminum foil, a resin film having an aluminum vapor-deposited film, a resin film having an inorganic oxide vapor-deposited film, an ethylene-vinyl alcohol copolymer film, and the like. In particular, since a metal detector for foreign matter inspection can be used, it is preferable to use a resin film having an inorganic oxide vapor deposition film as the barrier layer. Examples of the resin film forming the vapor-deposited film include a polyester film (particularly, a polyethylene terephthalate film), a polypropylene film, a nylon film, and the like, and in particular, these stretched films can be used.

As the vapor-deposited film of inorganic oxide, basically any vapor-deposited film of metal oxide can be used, and silicon (Si), aluminum (Al), magnesium (Mg), calcium (Ca), potassium ( Use a vapor-deposited film of metal oxides such as K), tin (Sn), sodium (Na), boron (B), titanium (Ti), lead (Pb), zirconium (Zr), and yttrium (Y). Can be done. Among them, a vapor-deposited film of an oxide of silicon (Si) and aluminum (Al) is preferable from the viewpoint of productivity and price. The inorganic oxide vapor deposition film can be formed on the resin film by a known method. For example, a chemical vapor deposition method, a physical vapor deposition method, or a combination of both can be used to form the inorganic oxide vapor deposition film on the resin film. can do.

The barrier layer may also be provided with a printed pattern layer in the same manner as the above-mentioned base material layer and an optional second base material layer.

The thickness of the barrier layer is preferably 5 μm or more, 7 μm or more, 10 μm or more, or 20 μm or more, and 60 μm or less, 50 μm or less, or 40 μm or less.

(Sealant layer)
The sealant layer used in one aspect of the present invention is a layer containing a resin having a heat-sealing property and an easy peeling property that can be welded to the mouth of the tube container by heating. In one embodiment, the sealant layer is composed of a blended resin having a sea-island structure in which two or more kinds of resins are blended, and the resin constituting the sea portion of the sea-island structure is a low softening point of the tube container mouth. A resin that is heat-sealed with the resin and that constitutes the island portion of the sea island structure is a resin that constitutes the sea portion of the sea island structure and a resin that has a higher softening point than the low softening point resin of the tube container mouth. is there.

The resin constituting the sea portion of the sea-island structure is selected according to the low softening point resin at the mouth of the tube container. As the resin constituting the sea portion of the sea island structure, a polyolefin resin (for example, low density polyethylene (LDPE), medium density polyethylene (MDPE), high density polyethylene (HDPE), polypropylene, ethylene-propylene copolymer, ethylene-α Olefin copolymer, ethylene-acrylic acid copolymer (EAA), ethylene-methacrylic acid copolymer (EMAA), ethylene-methacrylic acid ester copolymer, ethylene-acrylic acid ester copolymer, ionomer, ethylene-acetic acid Vinyl copolymer (EVA)), copolymerized polyester and the like can be mentioned.

The softening point of the resin constituting the sea portion of the sea island structure may be, for example, 130 ° C. or lower, 120 ° C. or lower, 110 ° C. or lower, 105 ° C. or lower, or 100 ° C. or lower, 90 ° C. or higher, or 95 ° C. or higher. There may be.

The resin constituting the island portion of the sea island structure is an incompatible or partially compatible resin with respect to the resin constituting the sea portion of the sea island structure, and is a low softening point resin at the mouth of the tube container and the sea island structure. Although it is selected according to the resin that constitutes the sea portion, the resin that constitutes the island portion of the sea island structure is a polyolefin resin (for example, low density polyethylene (LDPE)) that is different from the resin that constitutes the sea portion of the sea island structure. Examples thereof include medium-density polyethylene (MDPE), high-density polyethylene (HDPE), ethylene-α-olefin copolymer, polybutene, polypropylene, ethylene-propylene copolymer), and polystyrene resin. In addition to the above-mentioned resins, resins such as acid-modified products can be used.

The softening point of the resin constituting the island portion of the sea-island structure may be, for example, 170 ° C. or lower, 160 ° C. or lower, 150 ° C. or lower, 140 ° C. or lower, or 130 ° C. or lower, 110 ° C. or higher, 115 ° C. or higher, or It may be 120 ° C. or higher.

In addition to the sea portion of the sea-island structure and the resin constituting the island portion, a plurality of resins can be further blended for the purpose of controlling the sea-island structure and the coagulation / peeling mechanism.

In one aspect of the present invention, the resin constituting the island portion of the sea-island structure is 3% by weight or more, 5% by weight or more, 8% by weight or more, 10% by weight or more, based on the total weight of the resin having the sea-island structure. It may be contained in an amount of 20% by weight or more, or 30% by weight or more, and is contained in an amount of 50% by weight or less, 40% by weight or less, 30% by weight or less, 20% by weight or less, 10% by weight or less, or 5% by weight or less. You may be.

The softening point of the resin forming the sea part of the sea island structure is within ± 15 ° C, within ± 13 ° C, within ± 10 ° C, within ± 8 ° C, ± 5 ° C of the softening point of the low softening point resin at the mouth of the tube container. It is preferably within, or within ± 3 ° C. This is considered to be because the sealing temperature can be set more easily and the need to set the sealing temperature unnecessarily high is reduced.

More preferably, the softening point of the resin forming the sea portion of the sea island structure is lower than the softening point of the low softening point resin at the mouth of the tube container, and the softening point of the low softening point resin at the mouth of the tube container. It is preferably within -15 ° C, within -13 ° C, within -10 ° C, within -8 ° C, within -5 ° C, or within -3 ° C. In such an embodiment, it is considered that the delamination of the top sealing material caused by the contents penetrating between the base material layer / sealant layer can be further prevented.

In one aspect of the present invention, the softening point of the resin constituting the island portion of the sea island structure is higher than the softening point of the resin constituting the sea portion of the sea island structure and the low softening point resin layer at the mouth of the tube container. For example, the softening points of the resin constituting the island portion of the sea island structure are + 5 ° C. or higher, + 10 ° C. or higher, and +15 of the softening points of the resin constituting the sea portion of the sea island structure and the low softening point resin layer at the mouth of the tube container. It may be ℃ or more, + 20 ℃ or more, or + 30 ℃ or more, and may be + 100 ℃ or less, + 90 ℃ or less, + 80 ℃ or less, + 70 ℃ or less, or + 60 ℃ or less.

As used herein, the softening point refers to the temperature at which an endothermic peak appears when measured using differential scanning calorimetry (DSC) in accordance with JIS K7121. For example, in the present specification, the softening point may be a so-called glass transition point for an amorphous resin and a so-called melting point for a crystalline resin. Therefore, for amorphous resins, the glass transition point can be determined by the same measuring method as the softening point, and for crystalline resins, the melting point can be determined by the same measuring method as the softening point.

Specifically, when the softening point was measured by DSC, a container was filled with about 5.0 mg of a sample that had been allowed to stand for 24 hours or more at a temperature of 23 ± 2 ° C. and a relative humidity of 50 ± 5%. Then, the temperature was raised between 30 ° C. and 200 ° C. at a heating rate of 10 ° C./min under a nitrogen gas flow rate of 20 ml / min, and the endothermic peak temperature was measured. In general DSC measurement, in order to eliminate the influence of the heat history of the measurement sample, the temperature is raised once, then cooled, and the temperature is raised a second time, and the data at that time is used. There is. However, since the data at the time of the first temperature rise often corresponds to the behavior at the time of actual sealing, the softening point in the present specification is obtained from the DSC curve at the time of the first temperature rise as much as possible. The softening point to be used shall be adopted.

For example, FIG. 4A shows a blended resin containing linear low-density polyethylene having a softening point (melting point) of 104 ° C. as a sea portion and polypropylene having a softening point (melting point) of 129 ° C. as an island portion. It is a DSC curve. FIG. 4B is a DSC curve of a blended resin containing low-density polyethylene having a softening point (melting point) of 110 ° C. as a sea portion and polystyrene having a softening point (glass transition point) of 89 ° C. as an island portion. is there. In FIG. 4 (b), the peak at 89 ° C. is small, which is due to the low polystyrene content in the blended resin.

In one embodiment of the present invention, the sealant layer has a sea portion containing a polyethylene resin having a softening point or melting point of 90 ° C. or higher and 130 ° C. or lower, and a sea portion having a softening point or melting point of 110 ° C. or higher and 170 ° C. or lower. It is a layer of resin with a sea-island structure that contains an island portion containing polypropylene resin that is higher than the softening point or melting point, has heat-sealing properties that can be welded to the mouth of the tube container by heating, and is easy. It is a layer containing a resin having a peeling property. For example, the resin having the sea-island structure includes a sea portion containing a polyethylene resin having a softening point or melting point of 100 ° C. or higher and 120 ° C. or lower, and an island portion containing a polypropylene resin having a softening point or melting point of 110 ° C. or higher and 130 ° C. or lower. Contains. Also in this embodiment, the softening point or melting point of the polypropylene-based resin at the island portion of the sealant layer is preferably higher than the softening point or melting point of the low softening point resin at the container mouth.

(Manufacturing method of top seal material)
The top sealing material for a tube container of the present invention is a laminate having a base material layer, an optional barrier layer, an optional second base material layer, and a sealant layer. The top sealing material for a tube container of the present invention is produced by laminating a base material layer, an optional barrier layer, an optional second base material layer, and a sealant layer in this order by a dry laminating method, a sand laminating method, or the like. Can be done. Further, if necessary, in order to improve the adhesiveness of each layer, the adhesive surface of each layer is subjected to treatments such as corona discharge treatment, ozone treatment, and low temperature plasma treatment in advance, and the layers are bonded together to form the top seal for the tube container of the present invention. Wood can also be manufactured. The dry laminating method is a method in which an adhesive is applied, dried, pressed, and the adhesive is cured and bonded. Further, the sand laminating method is a method in which a resin or an adhesive resin constituting each layer melted between the film and the film to be bonded is extruded and bonded.

<Tube container>
In the tube container, the cross section of two or more resin layers containing resins having different softening points is exposed on the surface where the mouth of the tube container is sealed, and one of the two or more resin layers is the other. It is a tube container containing a low softening point resin having a softening point lower than that of the resin of the resin layer of. In addition, in this specification, a "tube container" also includes a tubular body whose end is not closed.

The low softening point resin layer at the mouth of the tube container is selected according to the resin forming the sea portion of the sea-island structure of the sealant layer, and is, for example, low density polyethylene (LDPE), medium density polyethylene (MDPE), or high density polyethylene (MDPE). It can contain density polyethylene (HDPE), metallocene-based polyethylene, polypropylene, ethylene-propylene copolymer, thermoplastic elastomer, polystyrene-based resin, ionomer, a mixture of modified polyolefin and low-density polyethylene (LDPE), and the like.

Low softening point of tube container mouth The softening point or melting point of the resin may be, for example, 130 ° C. or lower, 120 ° C. or lower, 110 ° C. or lower, 105 ° C. or lower, 100 ° C. or lower, or 95 ° C. or lower, and may be 80 ° C. or higher. , 90 ° C or higher, 95 ° C or higher, 100 ° C or higher, 105 ° C or higher, or 110 ° C or higher. For example, the low softening point resin in the mouth portion may be a polyethylene-based resin having a softening point or a melting point of 90 ° C. or higher and 130 ° C. or lower.

Examples of the resin layer other than the low softening point resin layer at the mouth of the tube container include a base material layer and a barrier resin layer. Further, there may be an adhesive layer that adheres these layers. The barrier resin layer may be composed of, for example, an ethylene-vinyl alcohol copolymer, a thermoplastic polyester resin, an acrylonitrile resin, a polyvinylidene chloride resin, or the like. Further, the base material layer may be composed of a resin selected from the same resin as the resin described for the base material layer of the top sealing material.

For example, the resin layer other than the low softening point resin layer may have a softening point of 110 ° C. or higher, 130 ° C. or higher, 150 ° C. or higher, or 170 ° C. or higher. It may be 180 ° C. or lower, or 160 ° C. or lower.

Examples of the tube container include a laminated tube container and a blow tube container.

(Laminate tube)
Laminate tubing uses a laminate, which is rolled into a tube and sealed at its polymerized ends to produce a tubular body, which is then injection molded into one opening of the tubular body, for example. It can be obtained by integrally molding the mouth and shoulders by a method, a compression molding method, or the like, and welding the body to the body by a high frequency or the like.

In this case, the laminated material of the tube container body and the laminated material of the tube container mouth and shoulder may be made of different materials or may be made of the same material. That is, the two or more resin layers having different softening points exposed on the surface where the tube container mouth is sealed may be the same two or more resin layers as the tube container body, or the tube container body. It may be two or more resin layers different from the two or more resin layers of the portion.

As a method of integrally molding a mouth portion having a plurality of layer structures and a shoulder portion by an injection molding method, a method of molding using a mold having a hot runner nozzle is known. As a molded product in which the mouth and shoulders having a plurality of layer configurations are integrally molded, the two layers of the inner surface side and the outer surface side are made of the same molten resin, and the molten resin for the intermediate layer is used between them. In general, a molded product having a two-kind, three-layer structure in which the layers are sandwiched.

(Blow tube)
The blow tube has a mouth, shoulders, and body integrally formed. The blow tube is formed by extruding a tubular molten resin from an extrusion die, introducing it into a halving mold, blowing air after closing the mold, and pressing the molten resin against the mold. A blow tube having a plurality of layer structures can be formed by using a plurality of extruders for extruding molten resin and extruding a plurality of different resins from the multilayer extrusion die.

In this case, the laminated material of the tube container body and the laminated material of the tube container mouth and shoulder are the same material. That is, the two or more resin layers having different softening points exposed on the surface where the tube container mouth is sealed are the same two or more resin layers as the tube container body.

Like the laminated tube, the blow tube also has a two-kind, three-layer structure in which two layers, the inner surface side and the outer surface side, are made of the same resin, and the intermediate layer between them is made of another resin. Tubes are common.

(Other)
In the case of a tube container having a two-kind, three-layer structure, the intermediate layer is preferably composed of the above-mentioned barrier resin in consideration of the storage stability of the contents of the container.

Further, an adhesive layer can be used to bond each layer of the tube container, and examples of the adhesive layer include modified polyethylene and ionomer. As the tube container, a laminate in which low density polyethylene / adhesive layer / ethylene-vinyl alcohol copolymer / adhesive layer / low density polyethylene is laminated in this order is generally used from the viewpoint of workability and the like.

<< Manufacturing example >>
(Example 1)
<Making a tube container>
A tube container for evaluation was obtained by blow molding. Specifically, a tube container is obtained by extruding a tubular molten resin from a multi-layer extrusion die, installing it in a two-split mold, blowing air after closing the mold, and pressing the molten resin against the mold. It was.

The obtained tube container had "LDPE (softening point: 111 ° C.) (thickness: 370 μm) / modified polyolefin adhesive layer (thickness: 12 μm) / EVOH (softening point: 182 ° C.) (thickness: 85 μm) / modified in the mouth. The layer structure was "polyolefin adhesive layer (thickness: 12 μm) / LDPE (softening point: 111 ° C.) (thickness: 370 μm)". The size of the molded tube container was an outer diameter of the mouth of φ9.4 mm, an inner diameter of the mouth of φ7.7 mm, an outer diameter of the body of φ24 mm, and a thickness of 350 μm.

<Making top seal material>
An aluminum foil was laminated on the corona-treated surface of PET via an adhesive to prepare a laminated body a. Subsequently, the corona-treated surfaces of the second PET were laminated facing each other on the aluminum foil of the laminated body a via an adhesive to prepare the laminated body b. Further, a sealant layer was laminated on the corona-treated surface of the second PET via an adhesive to prepare a top seal material. The obtained top seal material had a structure of "PET (thickness 12 μm) / aluminum foil (thickness 25 μm) / PET (thickness 12 μm) / sealant layer (thickness 30 μm)”.

Here, a two-component curable adhesive was used as the adhesive, and the coating amount of each adhesive was 3 g / m ² . Further, as a sealant layer, a sea-island structure in which polypropylene (PP) (softening point: 129 ° C.) (islands) is dispersed in linear low-density polyethylene (LLDPE) (softening point: 104 ° C.) (sea). The blended resin to have was used.

Each softening point of the material used for the tube container and the top sealing material is a value measured by the method described above using a differential scanning calorimeter (EXSTAR6000, Seiko Instruments Inc.).

(Example 2)
A tube container was prepared in the same procedure as in Example 1. Further, a top sealant was produced by the same procedure as in Example 1 except that the thickness of the sealant layer was 50 μm.

(Comparative Example 1)
A tube container was prepared in the same procedure as in Example 1. Further, as a sealant layer, a resin having a sea-island structure in which polystyrene (PS) (softening point: 89 ° C.) (islands) is dispersed in low-density polyethylene (LDPE) (softening point: 110 ° C.) (sea). A top sealant was prepared in the same procedure as in Example 1 except that the above was used.

(Comparative Example 2)
A tube container was prepared in the same procedure as in Example 1. Further, as a sealant layer, a resin having a sea-island structure in which low-density polyethylene (LDPE) (softening point: 107 ° C.) (islands) is dispersed in polypropylene (PP) (softening point: 161 ° C.) (sea). A top sealant was prepared in the same procedure as in Example 1 except that the above was used.

(Comparative Example 3)
A tube container was prepared in the same procedure as in Example 1. Further, as a sealant layer, a resin having a sea-island structure in which low-density polyethylene (LDPE) (softening point: 107 ° C.) (islands) is dispersed in polypropylene (PP) (softening point: 161 ° C.) (sea). A top sealant was prepared in the same procedure as in Example 1 except that the sealant layer was made to have a thickness of 50 μm.

《Evaluation》
(Test 1: Welding test with low softening point resin in the innermost layer of the tube container)
The body portion of the tube container and the top sealing material of each example were cut into strips having a width of 25 mm. Then, using a heat seal tester (TP-701-BS, Tester Sangyo Co., Ltd.), set the hot plate at each temperature shown in Table 1, press 2.5 kg / cm ² , time 0.6 seconds. Under heat-sealing conditions, the innermost layer (LDPE) of the tube container body of each example and the sealant layer of the top sealing material were heat-welded. Then, it was cut to a width of 15 mm to prepare a plurality of samples for each example. The welding strength of the samples of each example was measured a plurality of times using a strograph (VES10, Toyo Seiki Seisakusho Co., Ltd.).

The results are shown in Table 1.

In Examples 1 and 2, there was little variation in welding strength, and sufficient welding strength was obtained even in a wide temperature range. On the other hand, in Comparative Example 1, since the softening point of the resin in the sea portion is low, it is considered that the sea-island structure of the sealant layer is broken at a high temperature, so that the welding strength varies. Further, in Comparative Examples 2 and 3, it is considered that the resin in the sea portion does not melt at a low temperature due to the high softening point of the resin in the sea portion, and therefore does not weld at a low temperature.

(Test 2-1 and Test 2-2: Welding test with low softening point resin in the innermost layer of the tube container)
Except that the heat sealing conditions were pressing 2.0 kg / cm ² , time 0.6 seconds (test 2-1), pressing 2.0 kg / cm ² , time 1.0 seconds (test 2-2). The welding strength of the samples of Example 2 and Comparative Example 1 was measured by the same method as in Test 1.

The results are shown in Table 2.

Comparing Tests 2-1 and 2-2, in Comparative Example 1, when the sealing time was long, the welding strength varied especially under the condition that the sealing temperature was high, whereas in Example 2, the sealing time varied. Stable welding strength was obtained even when the length was increased.

(Test 3: Welding test at the mouth of the tube)
Top sealing material (40 mm × 25 mm square) of Examples 1 and 2 and Comparative Example 1 under heat sealing conditions of pressing 3.0 kg / cm ² and time 1.0 second by setting the hot plate to a predetermined temperature. And the mouth of the tube container were heat-welded to prepare a plurality of samples for each example. Then, the welding strength of each sample was measured a plurality of times using a strograph (VES10, Toyo Seiki Seisakusho Co., Ltd.).

The results are shown in Table 3.

In Comparative Example 1, the welding strength varied, whereas in Examples 1 and 2, stable welding strength was obtained.

(Test 4-1 and Test 4-2: Welding test at tube mouth [test condition change])
For Example 1 and Comparative Example 1, a top sealing material having a width of 30 mm was fed out, and a hot plate was continuously pressed against the mouth of the tube container from above and welded to prepare a sample. Then, the welding strength of a plurality of samples of each example was measured using a push-pull gauge (9500 series, Aiko Engineering Co., Ltd.). For welding, a temporary welding of the top sealing material was performed, and then a main welding of the top sealing material was performed.

The results are shown in Table 4.

Under the condition stronger than the aptitude condition (Test 4-2), the welding strength of Comparative Example 1 varied and the maximum value was 9.8 N, which was a sample that was difficult to open easily, whereas in Example 1, it was stable and stable. It showed an appropriate welding strength.

1a Base material layer 1b Second base material layer 2 Barrier layer 3 Sealant layer 3a Resin forming the sea structure of the sea island structure 3b Resin forming the island structure of the sea island structure 4a Low softening point resin layer 4b Other resin layer 10 Tube Top sealant for container 20 Cap 40 Tube Container mouth 50 Contents 60 Open end

Claims (11)

A tube container with a top sealing material having a top sealing material for sealing the mouth of the tube container and a tube container whose mouth is sealed with the top sealing material .
On the surface where the mouth of the tube container is sealed, a cross section of two or more resin layers containing resins having different softening points is exposed, and one of the two or more resin layers is another resin. Contains a low softening point resin that has a lower softening point than the layer resin,
The top sealant has at least a base material layer as the outermost layer and a sealant layer as the innermost layer.
The sealant layer is composed of a blended resin having a sea-island structure in which two or more kinds of resins are blended, and the resin constituting the sea portion of the sea-island structure is a heat-sealed resin with a low softening point at the mouth. a resin is, and the resin constituting the island part of the island structure is Ri resin der higher softening point than the low softening point resin of the resin and the mouth portion constituting the sea portion of the sea-island structure, and
The thickness of the sealant layer is more than 15 μm.
Tube container with top sealant . The tube container is composed of a laminate of two or more resin layers containing resins having different softening points, and the two or more resin layers of the laminate are sealed on the surface where the mouth portion of the tube container is sealed. The tube container with a top sealing material according to claim 1, which is a blow tube container whose cross section is exposed. The top sealing material according to claim 1 or 2, wherein the softening point of the resin constituting the sea portion of the sea island structure of the sealant layer is within ± 15 ° C. of the softening point of the low softening point resin of the mouth portion. Tube container . Softening point of the resin constituting the sea portion of the sea-island structure of the sealant layer is lower than the softening point of the low softening point resin of the mouth portion, the top sealing material according to any one of claims 1 to 3 With tube container . The low softening point resin at the mouth of the tube container is a polyethylene resin, and the resin constituting the sea portion of the sea island structure of the sealant layer is a polyethylene resin and constitutes the island portion of the sea island structure. The tube container with a top sealing material according to any one of claims 1 to 4, wherein the resin to be used is a polypropylene-based resin. A tube container with a top sealing material having a top sealing material for sealing the mouth of the tube container and a tube container whose mouth is sealed with the top sealing material .
On the surface where the mouth of the tube container is sealed, a cross section of two or more resin layers containing resins having different softening points is exposed, and one of the two or more resin layers is another resin. Contains a low softening point resin that has a lower softening point than the layer resin,
The top sealant has at least a base material layer as the outermost layer and a sealant layer as the innermost layer.
The sealant layer of the top sealing material is composed of a blended resin having a sea-island structure in which two or more kinds of resins are blended, and the sea portion of the sea-island structure has a softening point of 90 ° C. or higher and 130 ° C. or lower. includes a polyethylene resin, the island portions of the sea-island structure is higher than the softening point of the polyethylene resin is and the sea region 170 ° C. or less 110 ° C. or higher softening point, seen containing a polypropylene resin, and
The thickness of the sealant layer is more than 15 μm.
Tube container with top sealant . The tube container with a top sealing material according to any one of claims 1 to 6, which has a barrier layer between the base material layer of the top sealing material and the sealant layer of the top sealing material . The thickness of the sealant layer is 30 to 50 [mu] m, or preparative Ppushiru material-attached tube container according to one of claims 1 to 7. The tube container with a top sealing material according to any one of claims 1 to 8 , wherein the low softening point resin at the mouth of the tube container is a polyethylene resin having a softening point of 90 ° C. or higher and 130 ° C. or lower. The tube container with a top sealing material according to any one of claims 1 to 9 , wherein the end of the tube container is open so that the contents can be filled. The tube container with a top sealing material according to any one of claims 1 to 10 , which is filled with the contents.

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