JP2001253426A - Lightweight squeeze bottle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lightweight squeeze bottle in which the drop strength, the rigidity, the heat resistance, the forming property, and the transparency are considerably improved while reducing the weight of the container. SOLUTION: In this lightweight squeeze bottle comprising outer and inner layers containing an ethylene polymer and an intermediate layer containing a resin of gasbarrier property, at least one layer of the outer and inner layers comprises a layer containing ethylene α-olefine copolymer with a density of >=0.918 g/cm3, with a molecular weight distribution (Mw/Mn) of >=4.5, and with a melting point of >=116 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light weight squeeze bottle, and more particularly to a light weight squeeze bottle excellent in a combination of appropriate stiffness, heat resistance, transparency and other appearance characteristics and moldability.

[0002]

2. Description of the Related Art Various squeeze bottles made of polyethylene are widely used as a squeeze bottle for extruding contents by pressing deformation of a container wall. However, even if the container is made of polyethylene, for example, when high-density polyethylene is used, the heat resistance is excellent, but the transparency and the flexibility are inferior. And excellent transparency, but poor heat resistance.

As a solution to the above-mentioned drawbacks of polyethylene, there is known one using a linear low-density polyethylene (hereinafter, sometimes simply referred to as LLDPE) which is a copolymer of ethylene and α-olefin. (Japanese
-94756).

Japanese Utility Model Laid-Open No. 6-556 proposed by the present applicant.
No. 40 discloses a melt flow rate of 0.1 to 2.0.
Heat sterilization comprising a blow-molded product of a coextruded laminate of a linear low-density polyethylene substrate of 5 g / 10 min and an outer surface layer of a linear low-density polyethylene having a melt flow rate of 3 to 12 g / 10 min. A possible liquid pharmaceutical container is described.

Japanese Patent Application Laid-Open No. Hei 10-236451 discloses that the density obtained by using a metallocene catalyst is 0.92.
A weight ratio of 95: 5 to 60:40 of polyethylene or ethylene / α-olefin copolymer and high density polyethylene having a melt flow rate of 5 to 0.942 g / cm ³ and a melt flow rate of 1.0 to 15 g / 10 min. A blow-molded container characterized by being blow-molded from a parison provided with at least one layer of a composition comprising:

[0006]

In recent years, there has been a strong demand for lighter containers in the field of squeeze bottles in order to reduce resin costs and transportation costs required for manufacturing containers. However, when the weight of the container is reduced, the drop strength in the state where the contents are filled is reduced, and the rigidity of the container is lost, which causes a problem that workability at the time of filling the contents and handling of the container become difficult. Further, the influence of the heat deformability and the deformability under reduced pressure at the time of hot filling of the contents becomes large, and in the case of a lightweight container, the requirement for heat resistance is more severe. Furthermore, the influence of the moldability during blow molding is great, and there are problems such as shark skin generation on the resin layer surface, poor appearance due to disturbance due to abnormal flow, and reduced transparency.

In this type of squeeze bottle, a gas barrier resin layer is generally provided as an intermediate layer in order to prevent gas permeation through the vessel wall and loss of fragrance components in the contents. In order to bond the gas barrier resin layer and the inner and outer layers, a means of interposing an adhesive layer between these layers is employed. In the molding of a squeeze bottle, a parison to be melt-extruded is pinched off by a mold and a fluid is blown.
The bottles etc. that are prototyped at the time of adjustment are crushed and re-grinded (reproduction, also called repro for short)
After that, it is inserted as a layer in the bottle container wall.

However, in the case of a lightweight squeeze bottle, the handling of the regrind or repro is a troublesome problem. If the regrind or repro is used, the drop strength, rigidity, heat resistance, and the like are reduced due to the weight reduction of the container. Decrease in moldability, decrease in transparency, etc. are more likely to occur. For example, the regrind or repro contains a gas-barrier resin or the like as a matter of course, and burning or gelation due to poor dispersion of the resin is an obstacle.

Further, in order to omit the printed outer layer bag and eliminate the troublesome label sticking operation after the bottle is formed, the label is stuck in the mold (in-mold label, IML) at the time of forming the bottle. Is often performed, but in a lightweight squeeze bottle with a thinner wall, the in-mold labeling (I
There is also a problem that the ML) operation does not proceed smoothly.

[0010] Further, it is common practice to put a logo mark on the container wall of the bottle due to the unevenness of the container wall for the purpose of increasing the commercial value of the bottled product and clarifying the source of the product. It is difficult to make clear logos clearly appear with a lightweight squeeze bottle.

Accordingly, it is an object of the present invention to provide a light-weight squeeze bottle in which the container is reduced in weight, but the drop strength, rigidity, heat resistance, moldability and transparency are remarkably improved. Another object of the present invention is to provide a light-weight squeeze bottle in which the resin of the regrind or the repro is dispersed well even when the regrind or the repro of the bottle is reused, and which exhibits the above-mentioned excellent characteristics. Still another object of the present invention is to provide a light-weight squeeze bottle capable of attaching a label in a mold (IML) and facilitating the formation of a logo mark while the wall of the container is thinned.

[0012]

According to the present invention, in a squeeze bottle comprising an inner and outer layer containing an ethylene polymer and an intermediate layer containing a gas barrier resin, at least one of the inner and outer layers has a density of at least one. A lightweight squeeze comprising a layer containing an ethylene / α-olefin copolymer having a molecular weight distribution (Mw / Mn) of at least 0.918 g / cm ³ and a melting point of at least 116 ° C. A bottle is provided. In the lightweight squeeze bottle of the present invention: 1. The ethylene / α-olefin copolymer has a melt tension of 3 g or more (melt tension measured at 190 ° C.); 2. the layer containing the ethylene / α-olefin copolymer comprises a blend of virgin ethylene / α-olefin copolymer and bottle regrind; 3. Regrind is contained in an amount of 5 to 80% by weight; 4. The layer containing the ethylene / α-olefin copolymer is provided in a thickness of 30 to 95% of the total thickness of the bottle; 5. The innermost layer and / or outermost layer made of low-density polyethylene or ethylene-vinyl acetate copolymer is laminated on the inner layer and / or outer layer containing the ethylene / α-olefin copolymer, A gas barrier resin intermediate layer, an adhesive layer provided on both sides of the gas barrier resin intermediate layer, an inner layer and / or an outer layer comprising a blend of a virgin ethylene / α-olefin copolymer and a bottle regrind, It is preferable to have a layer structure of the innermost layer and the outermost layer made of low-density polyethylene or ethylene-vinyl acetate copolymer.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [Operation] The lightweight squeeze bottle of the present invention comprises an inner / outer layer containing an ethylene polymer and an intermediate layer containing a gas barrier resin, and at least one of the inner / outer layers has a density of at least one. 0.918 g / cm ³ or more,
Molecular weight distribution (Mw / Mn) is 4.5 or more and melting point is 1
It is characterized by comprising a layer containing an ethylene / α-olefin copolymer at 16 ° C. or higher.

First, at least one of the inner and outer layers has a density of 0.918 g / cm ³ or more, particularly 0.922 to 0.9.
It is important to contain an ethylene / α-olefin copolymer of 32 g / cm ³ , so that even when the vessel wall is thinned for the purpose of weight reduction, high strength is maintained and drop resistance is improved. Is also excellent.

That is, in the case of ordinary high-pressure low-density polyethylene (LDPE) having a density in the above range, when the wall of a squeeze bottle is made thinner, the drop strength is significantly affected, and as shown in Comparative Example 1 described later. As the basis weight decreases from 30 g to 27 g and 24 g, the frequency of breakage due to dropping of the bottle increases. On the other hand, when the above-mentioned ethylene / α-olefin copolymer is used, even when the basis weight is reduced, breakage due to falling can be effectively prevented. This is particularly noticeable when an in-mold label (IML) is applied to a wall or a logo is provided on a body wall. In the squeeze bottle of Comparative Example 1 cited above, while the bottle was broken at the time of the logo mark, the ethylene / α-
In a bottle using an olefin copolymer, such occurrence of breakage is not observed at all, and according to the present invention, at the same time as reducing the wall thickness to reduce the weight of the container wall, disposing an in-mold label, forming a logo mark, and the like. Can be freely done.

The ethylene / α-olefin copolymer having the above density is called linear low-density polyethylene and has a short side chain based on α-olefin in molecular structure. The chain structure is linear. The linear low-density polyethylene (LLDPE) has a higher tensile strength than the low-density polyethylene (LDPE) obtained by the high-pressure method.
It has the advantages of high impact strength and rigidity, large elongation, and excellent heat resistance and environmental stress crack resistance.
Also in the present invention, these advantages are exhibited by using the above-mentioned ethylene / α-olefin copolymer as at least one of the inner and outer layers.

The density of the ethylene / α-olefin copolymer is affected by the content of the comonomer α-olefin, and monotonously decreases as the content increases. It is important that the density of the copolymer is 0.918 g / cm ³ or more in order to maintain the rigidity of the container, heat resistance during hot filling (heat deformation resistance), and deformation resistance under reduced pressure. is there.
On the other hand, if the density exceeds 0.932 g / cm ³ , the transparency of the container tends to be impaired, and the vessel wall becomes hard, the squeezability of the contents decreases, and squeeze remains in the bottle. It is not preferable.

It is important that the ethylene / α-olefin copolymer used in the present invention has a molecular weight distribution (Mw / Mn) of 4.5 or more, preferably more than 5.0. This molecular weight distribution is measured by gel permeation chromatography (GPC) using narrow molecular weight distribution polystyrene as a reference polymer. Generally, ordinary linear low-density polyethylene (LLPPE) has a narrow molecular weight range, small Mw / Mn, and low-density polyethylene (LDPPE).
Compared with E), there is a disadvantage that the moldability and the transparency are inferior. In the present invention, moldability and transparency can be improved by using the ethylene / α-olefin copolymer having a wide molecular weight distribution as described above.

That is, the molecular weight distribution (Mw / Mn) is 4.5
When a lower ethylene / α-olefin copolymer is used for the inner and outer layers, as shown in Comparative Examples 2, 3 and 4 described later, a remarkable sharkskin is generated in the inner and outer layers, and the haze value of the formed bottle Is significantly large, and the light transmittance is considerably reduced. On the other hand, when the ethylene / α-olefin copolymer having the molecular weight distribution (Mw / Mn) is used, the moldability can be improved, the haze value can be reduced, and the transparency can be improved. is there.

The ethylene / α-olefin copolymer having the above-mentioned molecular weight distribution (Mw / Mn) is excellent in extrusion moldability and blow moldability, and the resin pressure for extrusion can be low. The current load of the extruder can be reduced, and it is excellent in workability and energy saving. Furthermore,
By using this resin for the inner and outer layers, there is an advantage that the temperature of the resin at the time of molding can be considerably reduced. In particular, when ethylene-vinyl alcohol copolymer (EVOH) is used as the gas barrier resin, the heat resistance is unstable, and problems such as burning and gelation are likely to occur. Therefore, the occurrence of these defects can be considerably reduced. Also, since the resin temperature can be reduced, the parison at the time of blow molding can be stabilized, and in particular, in the case of rotary blow molding, thickness fluctuation between dies can be reduced, which is an advantage in forming a thin bottle. Is a significant advantage.

Further, the above-mentioned ethylene.α-
The olefin copolymer also has excellent regrind dispersibility. This is because the viscosity at relatively low shear is high and the kneadability is excellent, reflecting a wide molecular weight distribution. As already pointed out, it is very important to reuse scrap resin generated during bottle molding as regrind for resource saving and waste reduction. Has the advantage that the kneading is carried out extremely smoothly. That is, the regrind contains a gas barrier resin such as an ethylene-vinyl alcohol copolymer, which causes problems such as poor dispersion of the resin, scorching, and generation of a gel. In the α-olefin copolymer, these resins can be dispersed well, and the above-mentioned trouble can be solved in combination with the fact that the resin temperature during molding can be considerably reduced.

The density and molecular weight distribution (M
(w / Mn) ethylene / α-olefin copolymer, especially LLD of Ziegler-based or chromium-based catalyst
PE has a higher crystallization temperature than conventional LDPE,
The crystallization rate is higher when compared at the same temperature below the melting temperature. Therefore, there is an advantage that it can be taken out of the mold at a higher temperature during blow molding, and the cooling time can be shortened. This effect tends to be even more remarkable as the bottle becomes thinner. In addition, LL of metallocene catalyst
In the case of DPE, the crystallization temperature is not so high, but the crystallization speed is high, so that the same effect is obtained. Further, depending on the type of the catalyst, a plurality of melting peaks may be possessed, and the high melting point peak may have a more remarkable effect. Such a tendency also brings about the effect that the shrinkage ratio of the bottle becomes smaller, and is advantageous in that the molding value of the bottle is kept within a predetermined range even if the molding is performed with the same mold at different molding speeds. In addition, when the IML is used, the present invention is also effective in preventing local deformation of the bottle due to a difference in shrinkage between the bottle and the label.

The ethylene / α-olefin copolymer used in the present invention should have a melting point of 116 ° C. or more from the viewpoint of heat resistance. If the melting point is lower than 116 ° C, the container may be deformed during hot filling at a temperature of about 85 ° C,
This is not preferred because the shape retention of the nozzle is reduced. In the case of having a plurality of melting points, the peak on the high temperature side often contributes to heat resistance.

Further, the ethylene / α-olefin copolymer having a melt tension of 3 g or more prevents the drawdown of the parison, and allows the wall thickness of the body and the wall thickness of the nozzle to be accurately determined. It is preferable for controlling the temperature. That is, when the melt tension of the ethylene / α-olefin copolymer is less than 3 g, as shown in Comparative Examples 5 and 6 described below, drawdown and wall thickness change are likely to occur, but the melt tension falls within the above range. If so, these troubles can be prevented.

In the lightweight squeeze bottle of the present invention,
The layer containing the ethylene / α-olefin copolymer may be a layer of the ethylene / α-olefin copolymer alone, or a blend of the virgin ethylene / α-olefin copolymer and a bottle regrind. It may be a layer made of an object or a combination of these layers. As already pointed out, by blending the regrind of the bottle with the ethylene / α-olefin copolymer and using it for a part of the bottle wall, the resources can be effectively used without the various problems described above. . In this case, it is preferable to use a virgin ethylene / α-olefin copolymer for the outermost layer and the innermost layer of the bottle from the viewpoint of hygienic properties. In this case, it is desirable to select a resin system independent of the main layer material in consideration of shark skin and transparency at the time of molding.

When a regrind is blended with the ethylene / α-olefin copolymer, the regrind blending ratio in this layer is preferably 5 to 80% by weight, more preferably 10 to 70% by weight. If the compounding ratio of the regrind exceeds the above-mentioned range, the layer roughness of this layer becomes conspicuous, and the mechanical properties and optical properties tend to decrease, which is not preferable. On the other hand, from the trouble when blending the regrind into the ethylene / α-olefin copolymer,
It is not economical if the mixing ratio is less than the above.

In the lightweight squeeze bottle of the present invention,
It is preferable for the purpose of the present invention that the layer containing the ethylene / α-olefin copolymer is provided in a thickness of 30 to 95% of the total thickness of the bottle. That is, when the thickness ratio is below the above range, the above-mentioned advantage due to the use of the specific ethylene / α-olefin copolymer tends to be impaired, while when the thickness ratio exceeds the above range, the gas barrier property Etc., the overall evaluation of bottles tends to decrease.

In the lightweight squeeze bottle of the present invention,
An innermost layer and / or an outermost layer made of low-density polyethylene or ethylene-vinyl acetate copolymer may be laminated on the inner layer and / or outer layer containing the ethylene / α-olefin copolymer. LDPE, EVA for outer layer
By providing such an ethylene-based resin, external haze can be reduced and gloss and transparency can be improved. Further, the air hole seal of the nozzle / finish can be carried out as before. Furthermore, when repro is blended in the recycle layer, the repro dispersibility can be improved, and the transparency can be maintained at a higher level.

In the lightweight squeeze bottle of the present invention, the gas barrier resin intermediate layer, the adhesive layers provided on both sides of the gas barrier resin intermediate layer, the virgin ethylene / α-olefin copolymer, and the bottle regrind are used. Most preferably, it has an inner layer and / or outer layer made of a blend of the above, and an innermost layer and an outermost layer made of low-density polyethylene or ethylene-vinyl acetate copolymer. The multilayer container having the above-described configuration is excellent in overall evaluation as a container in consideration of gas barrier properties, fragrance retention, and the like, in addition to the various advantages described above.

[Ethylene / α-olefin copolymer] The ethylene / α-olefin copolymer used in the present invention has a density of 0.918 g / cm ³ or more, particularly 0.922 to 0.932 g / cm ³ . A molecular weight distribution (Mw / Mn) of 4.5 or more, especially greater than 5.0, and a melting point of 116 ° C.
That's all. The melt tension of the copolymer is preferably 3 g or more.

As the α-olefin constituting the copolymer, those having 4 to 8 carbon atoms are preferable, butene-1, pentene-1, hexene-1, 4-methylpentene-1, heptene and the like. -1, octene-1, etc., alone or in combination of two or more. The content of these α-olefin comonomers is specified in an amount that falls within the above-mentioned density range. That is, as the content of the α-olefin increases, the density of the copolymer monotonously decreases, and generally, as the number of branched carbon atoms of the α-olefin comonomer increases, the degree of decrease in the density tends to increase. . In consideration of these, the type and content of the α-olefin comonomer should be determined so that the density is within the above range.

In order to obtain an ethylene / α-olefin copolymer having a wide molecular weight distribution (Mw / Mn), it is necessary to use a plurality of continuous polymerization processes such as two-stage polymerization, if necessary, in addition to selecting a polymerization catalyst. Can be. As the polymerization method, various methods such as a known gas phase, solution, slurry, and high pressure method can be used. As the catalyst, Ziegler catalyst,
A chromium catalyst, a metallocene catalyst, or the like is used. When the polymerization is carried out in multiple stages, the catalyst, the comonomer to be used and the like may be different in each step. Further, in the granulation step after polymerization, low-density polyethylene (LDPE), ethylene-polymerized by another process in order to improve moldability and transparency, in a range that does not impair the productivity of polymerization. An ethylene resin such as vinyl acetate copolymer (EVA), linear low density polyethylene (LLDPE), or high density polyethylene (HDPE) may be blended. The form of the molecular weight distribution may be a gentle and wide distribution or a so-called bimodal distribution with two peaks. Further, those having different composition distributions are also possible. As a comonomer, it is also effective to use an α-olefin having a carbon number of so-called HAO: C5 or more in order to secure good physical properties with a relatively low degree of polymerization and to obtain a high melt tension.

The ethylene / α-olefin copolymer used in the present invention has a melt flow rate (MFR, JIS K6
922-2) is generally 0.2 to 10.0 g / 10 m
in, particularly preferably in the range of 0.5 to 5.0 g / 10 min, from the viewpoint of balance between moldability and drop strength. Known additives can be added to each resin used in the present invention. In the ethylene / α-olefin copolymer, particularly when a Ziegler catalyst is used, a neutralizing agent such as a fatty acid metal salt such as calcium stearate or a natural or synthetic hydrotalcite is used for the purpose of neutralizing the residue. Phenolic as required,
Additives such as phosphorus and hindered amine can be used as antioxidants. When used for the outermost layer of the container, a known fatty acid amide-based lubricant can be used in a known addition amount. By making the innermost layer that is in direct contact with the contents no addition or addition of only a neutralizing agent, even if an antioxidant is added to the resin of the main layer, it is possible to substantially prevent migration to contents. it can.

[Gas Barrier Resin] The gas barrier resin generally has an oxygen permeability coefficient (PO2) of 5.5 × 10 5
^{-1 2 cc · cm / cm 2} sec · cmHg or less, particularly 4.5 × 10 ^-12 cc
A material having a transparency of not more than cm / cm ² sec · cmHg and having transparency is preferably used. The most suitable example of the barrier resin is an ethylene-vinyl alcohol copolymer (EVO).
H), for example, when the ethylene content is 2
A copolymer obtained by saponifying an ethylene-vinyl acetate copolymer having a saponification degree of 96 mol% or more, particularly 99 mol% or more, from 0 to 60 mol%, particularly 25 to 50 mol%. Compound is used. The saponified ethylene-vinyl alcohol copolymer should have a molecular weight sufficient to form a film, and is generally 0.01 dl / mol as measured at 30 ° C. in a 85:15 phenol: water mixture by weight. It is desirable to have a viscosity of at least g, especially at least 0.05 dl / g. Further, a homopolyamide, a copolyamide or a blend thereof containing from 3 to 30, especially from 4 to 25 amide groups per 100 carbon atoms is preferably used. In particular, the polyamide includes a polycondensate of an aliphatic acid and an aromatic diamine, such as a polycondensate of metaxylylenediamine and adipic acid. In this case, those in which the terminal group is blocked with a specific functional group are used in consideration of recyclability. Of course, the above-mentioned ethylene-vinyl alcohol copolymer and polyamide can be used in the form of a blend, and within a range that does not significantly impair the practical barrier properties, for example, within a range of 30% by weight or less, A thermoplastic resin, for example, a resin that imparts adhesion to a polyolefin such as a polyolefin or an ionomer, or the like can also be used as a blend.

As the moisture barrier resin, a cyclic olefin-based copolymer can be used, which comprises an amorphous to low-crystalline copolymer (COC) of an olefin and a cyclic olefin. As the olefin constituting the copolymer, ethylene is preferable, but propylene, 1-butene, 1-pentene, 1-hexene,
Α-olefins having 3 to 20 carbon atoms, such as -octene, 3-methyl 1-pentene and 1-decene, are used alone or in combination with ethylene. As the cyclic olefin, basically, an alicyclic hydrocarbon compound having an ethylenically unsaturated bond and a bicyclo ring, particularly bicyclo [2,
[2,1] is a hydrocarbon compound having a hept-2-ene skeleton. This copolymer (COC) is derived from 50 to 22 mol%, in particular 40 to 22 mol%, of cyclic olefins and the balance of ethylene and has a temperature below 200 ° C., in particular 150 ° C.
It preferably has a glass transition point (Tg) of from about 60 ° C. to about 60 ° C.
The molecular weight of the copolymer is not particularly limited, but it is preferable that the copolymer has an intrinsic viscosity [η] of 0.1 to 20 dL / g measured in decalin at 135 ° C.
It is generally at most 10%, especially at most 5%, as measured by X-ray diffraction.

These oxygen-barrier resins and moisture-barrier resins may be used alone or in combination.

[Laminated Structure] The lightweight squeeze bottle of the present invention basically comprises an inner and outer layer containing an ethylene-based polymer and an intermediate layer containing a barrier resin, and at least one of the inner and outer layers is made of ethylene. -It can have an arbitrary layer constitution under the condition of containing an α-olefin copolymer.

As the inner and outer layers containing the ethylene polymer, the above-mentioned ethylene / α-olefin copolymer (LL)
DPE), blends of virgin ethylene / α-olefin copolymer with bottle regrind (BRG) (LLDPE + BRG), low density polyethylene (LDP)
E), ethylene-vinyl acetate copolymer (EVA) and the like.

The laminate used in the present invention preferably has at least one layer composed of a blend (LLDPE + RGB) of a virgin ethylene / α-olefin copolymer and a bottle regrind. The regrind compounding ratio in this layer is 5 to 80% by weight, preferably 10 to 7% by weight.
It is preferably 0% by weight. This blend shows some practical adhesion to ethylene vinyl alcohol copolymer (EVOH) as well as ethylene polymer.

In the production of the laminate, an adhesive resin may be interposed between the resin layers as necessary, as an adhesive layer (AD), or the adhesive resin may be blended with one or both of the resin layers to be bonded. Thus, the adhesiveness can be improved.

Examples of such an adhesive resin include carbonyl (-C) based on carboxylic acid, carboxylic anhydride, carboxylate, carboxylic amide, carboxylic ester and the like.
-) 1 to 700 milliequivalent (meq) / 100 g resin, particularly 10 to 500 me
A thermoplastic resin contained at a concentration of q / 100 g resin. Suitable examples of the adhesive resin include ethylene-acrylic acid copolymer, ionic cross-linked olefin copolymer, maleic anhydride-grafted polyethylene, maleic anhydride-grafted polypropylene, acrylic acid-grafted polyolefin,
Ethylene-vinyl acetate copolymer, copolyester,
One or a combination of two or more such as copolymerized polyamide.

An example of a suitable laminated structure is as follows, but the present invention is not limited to this example. In the following example of the laminated structure, the left side is shown as the inner surface side of the container. Three-layer structure: LLDPE / EVOH + AD / LLDPE,
LLDPE + BRG / EVOH + AD / LLDPE + B
RG, LLDPE + AD / EVOH / LLDPE + BR
G, four-layer structure: LLDPE / LLDPE + BRG / EVOH
/ LLDPE + AD, LLDPE + BRG / EVOH +
AD / LLDPE + BRG / LDPE orEVA, L
LDPE / EVOH + AD / LLDPE + BRG / LL
DPE, LLDPE / COC / EVOH + AD / LLD
PE, LLDPE / LLDPE + BRG / EVOH / L
LDPE + BRG, 5-layer structure: LLDPE / LLDPE + BRG / EVOH
/ LLDPE + BRG / LLDPE, LLDPE / AD
/ EVOH / LLDPE + BRG / LLDPE, LLD
PE / LLDPE + BRG / COC / LLDPE + BR
G / LLDPE, LLDPE / AD / EVOH / AD /
LLDPE, 6-layer structure: LLDPE / AD / EVOH / AD / LLD
PE + BRG / LLDPEorLDPEorEVA, L
LDPE / LLDPE + BRG / AD / EVOH / AD
/ LLDPEorLDPEorEVA, LLDPE / A
D / EVOH / AD / COC / LLDPE, 7-layer structure: LLDPE / LLDPE + BRG / AD / E
VOH / AD / LLDPE + BRG / LLDPE, LD
PE / LLDPE + BRG / AD / EVOH / AD / L
LDPE + BRG / LDPE, LDPE / LLDPE +
BRG / AD / EVOH / AD / LLDPE + BRG /
EVA, EVA / LLDPE + BRG / AD / EVOH
/ AD / LLDPE + BRG / EVA, LLDPE / C
OC / AD / EVOH / AD / LLDPE + BRG / L
LDPE, 8-layer structure: LLDPE / LLDPE + BRG / COC /
AD / EVOH / AD / LLDPE + BRG / LLDP
E,

[Light Weight Squeeze Bottle] In FIG. 1 showing an example of the light weight squeeze bottle of the present invention and FIG. 2 showing a partial cross-sectional view in which a label edge portion is enlarged, this light weight squeeze bottle is provided with an in-mold label (IML) 1. Bottle 3 The bottle 3 is connected to the trunk A, the lower end of the trunk, and a closed bottom B formed by pinch-off of a parison (bottle base material). Of the mouth C. The bottle base (wall) 5 is formed from the above-described laminated parison. FIG. 2 shows the edge of the label 1 and the bottle base 5
Shows the positional relationship in the horizontal cross section with
Is flush with the outer surface of the bottle base material 5, and the label 1 is embedded in the bottle base material in this positional relationship. For this reason, the label edge portion 4 is likely to be a structurally weak portion, but according to the present invention, it is possible to effectively prevent the label edge portion 4 from being broken by falling.

In FIG. 3 showing another example of the lightweight squeeze bottle of the present invention and FIG. 4 showing an enlarged partial cross-section of a portion at the time of the logo mark, the lightweight squeeze bottle has a logo mark 2 composed of radial irregularities. It consists of a bottle 3 formed. The bottle 3 is connected to the trunk A, the lower end of the trunk, and a closed bottom B formed by pinch-off of a parison (bottle base material). Of the mouth C. The bottle base 5 is formed from the laminated parison described above. FIG.
This shows the positional relationship between the logo mark 2 and the bottle base material 5. The logo mark 2 and the bottle base material 5 have a step at the edge 6, and therefore this portion is structurally weak. However, according to the present invention, it is possible to effectively prevent breakage due to dropping of the portion at the time of the logo mark.

Four types 7 as an example of a laminated structure of a bottle base material
In FIG. 5 showing the laminated structure of the layers, this bottle base material is:
From the outer side, a surface layer 10 composed of an ethylene polymer, a regrind-containing ethylene / α-olefin copolymer layer 9, an adhesive resin layer 7, a gas barrier resin layer 8, an adhesive resin layer 7, a regrind-containing ethylene It has a layer configuration of an α-olefin copolymer layer 9 and a surface layer 10 made of an ethylene-based polymer. In FIG. 6 showing a laminated structure of three types and five layers, which is another example of the laminated structure of the bottle base material, the bottle base material has a surface layer 10 made of an ethylene-based polymer, -It has a layer configuration of an α-olefin copolymer layer 9, an adhesive-containing gas barrier resin layer 11, a regrind-containing ethylene / α-olefin copolymer layer 9, and a surface layer 10 made of an ethylene-based polymer. . In FIG. 7, which shows a laminated structure of four types and six layers, which is still another example of the bottle base material laminated structure, the bottle base material has a surface layer 1 made of an ethylene polymer from the outer surface side.
0, an adhesive resin layer 7, a gas barrier resin layer 8, an adhesive resin layer 7, a regrind-blended ethylene / α-olefin copolymer layer 9, and a surface layer 10 made of an ethylene-based polymer.

In the lightweight squeeze bottle of the present invention, the thickness of the bottle body at the maximum diameter portion varies depending on the internal volume, but is generally 0.20 to 1.20 mm, particularly
It is desirable to be in the range of 0.25 to 1.00 mm. If the thickness of the vessel wall is below the above range, the drop strength of the container tends to be insufficient, while if it exceeds the above range,
Contrary to the object of the present invention of reducing the weight of the container, the transparency and the extrudability of the content tend to decrease.

In the lightweight squeeze bottle of the present invention,
It is preferable for the purpose of the present invention that the layer containing the ethylene / α-olefin copolymer is provided in a thickness of 30 to 97% of the total thickness of the bottle.

The molding of the lightweight squeeze bottle can be carried out by a known melt molding method using the above-mentioned laminated parison. For example, there is a method using a single-head or multi-head direct blow extrusion blow molding machine, a rotary blow molding machine that continuously extrudes and molds a plurality of dies while rotating, and in which a multilayer parison is melt-extruded, and It can be manufactured by so-called blow molding, in which the material is supplied into a split mold and a fluid is blown into the mold to expand the material. As a molding die, an ordinary one having a flat inner surface can be used, or a mold having fine irregularities formed on the inner surface of the die can be used. For production of the multilayer extruded product, a co-extrusion molding method known per se can be used. For example, the extrusion molding may be performed using a multilayered multiple die using a number of extruders according to the type of the resin. As a form of squeeze bottle,
Due to the molding method, there may be a form similar to a blow tube.

In order to manufacture the container with an in-mold label (IML) of the present invention, the label may be positioned and attached to a cavity mold in advance, and the parison may be blow-molded with this mold. As the label, a biaxially stretched, uniaxially stretched, or unstretched plastic film, for example, polypropylene, high-density polyethylene, a polyester film printed is used, on the adhesive surface with the bottle, a hot melt adhesive, A polyethylene adhesive or the like can be applied. Further, when forming an irregular logo mark on a bottle body or the like, it is preferable to form an irregular pattern for forming the logo mark in the cavity mold in advance.

[0050]

The present invention will be further described with reference to the following examples, but the present invention is not limited to these examples.

Example 1 In comparison with the conventional material,
Virgin layer (10%) / virgin + repro layer (26
%) / Barrier material layer (4%) / (52%) / (1
0%) with a capacity of 1100 of 3 types and 5 layers (3M5L)
The bottles were rotary blow-molded at a discharge rate of 150 kg / hour with a mold having logo marks on the front and back sides of the body, with 30 g, 27 g, and 24 g with a momme.

Here, in the present invention 1-1-3, WDLL
DPE / WDLLDPE + Repro / EVOH / WDL
Configuration of LDPE + Repro / WDLLDPE, the present invention 2-
In 1-3, LDPE / WDLLDPE + Repro / EV
OH-based / WDLLDPE + Lipro / LDPE, Comparative Examples 1-1 to 3 show LDPE / LDPE + Lipro / E
VOH / LDPE + Repro / LDPE, Comparative Example 2-1
In ~ 3, NDLLDPE / NDLLDPE + Repro /
EVOH / NDLLDPE + Repro / NDLLDPE
A bottle with the following configuration was created. Here, the specification of the resin used is as follows.

[0053]

[Table 1]

Table 2 shows the obtained results. as a result,
In the configuration using the conventional LDPE, when it falls, it is broken starting from the logo mark. In addition, sharkskin is generated and transparency is significantly impaired. Good drop strength. The low temperature drop strength and transparency are shown below.

[0055]

[Table 2]

Example 2 Here, the same mold as in Example 1 was used, and a virgin layer (10%) was applied from the outer surface of the container.
/ Virgin + repro layer (26%) / adhesive layer (1
%) / Barrier material layer (2%) / adhesive material layer (1%) /
(52%) / (10%) Using a laminated parison composed of 4 types and 7 layers (4M7L), with a basis weight of 24 g and a thickness 80 having a foamed PP layer as a constituent layer in both molds at the time of molding.
A similar bottle was molded while the micron IML was inserted. FIG. 5 shows a laminated structure, and FIG. 1 shows a bottle shape.

Here, as the main resin, the molecular weight distribution M
In order to clarify the moldability of w / Mn containers and the criticality of numerical values on performance, the following resins are used as different Mw / Mn resins, respectively, and a resin made of maleic anhydride-modified LLDPE is used as an adhesive. EVOH having an ethylene content of 32 mol% was used as a barrier material.

[0058]

[Table 3]

Table 4 shows the obtained results. When Mw / Mn is less than 4.5, sharkskin is formed on the inner and outer layer surfaces which come into contact with the dies at the time of high discharge, so that the transparency is significantly reduced. Also, due to the unevenness of the surface, small bubbles were generated on the bonding surface of the IML. Metallocene catalyst LL with narrow distribution
In the case of DPE, it was difficult to adjust the thickness of the bottle in the height direction because the drawdown was large, and the uneven thickness of the body was significantly increased. In addition, it was recognized that the dimensions of the nozzle were not stable and the fitting property with the cap was poor.

[0060]

[Table 4]

[Embodiment 3] As in Embodiment 2 of the present invention, LDM is used for the outer layer, and the same 4M7L as in Embodiment 2 is used.
In order to clarify the criticality of the numerical value that the melt tension (MT) of the main resin has on the moldability and performance of the container,
A bottle with an IML was prepared in the same manner as in the previous example using a resin having a substantially constant FR and a different MT shown below as a main layer resin.

[0062]

[Table 5]

Table 6 shows the obtained results. When the melt tension falls below 3.0 g, the drawdown becomes large, and Comparative Example 5,
As in the case of No. 6, there is a tendency that the thickness control becomes difficult and it is easy to be broken by dropping. In addition, while the reproducibility of the repro was lowered and the transparency was lowered, the number of aggregated particles was increased, so that there was a tendency that breakage in the layer and Miguel increased. This tendency became remarkable with a decrease in the melt tension, and it was found that even if the metallocene catalyst LLDPE originally improved in transparency, its characteristics could not be utilized. As a result of the parison being stabilized in combination with the outer layer LDPE at MT 3.0, it is recognized that the unevenness is small and the moldability is good. It was also found that a bottle having good reproducibility of the hue of the contents in addition to the transparency was obtained because the dispersion of the repro was stabilized, and a certain degree of fine particles and uniform dispersion were achieved.

[0064]

[Table 6] Additives Ethylene / α-olefin copolymer may cause abnormally high shear stress at the die interface during high-speed, high-discharge from the die, or abnormal flow at the resin layer interface with different fluidity. Various additives may be used for the purpose of improving the state of contact at the interface in order to prevent the occurrence of the problem. As an effective additive, a fatty acid metal salt or a polyolefin resin component modified with a halogen element such as fluorine is added and used.

Example 4 Here, the same mold as in Example 1 was used, and the virgin layer (10%) / adhesive layer (1.5%) / barrier material layer (3%) / adhesive Layer (1.5%) / virgin + repro layer (74%) /
(10%) 4 types and 6 layers (4M6L) (invention 7), the same configuration except that the virgin layer resin of the outer layer is changed (invention 8), virgin + repro layer (20%) /
Adhesive layer (1.5%) / Barrier material layer (3%) / Adhesive layer (1.5%) / Virgin + repro layer (74%)
(3M5L) (invention 9) was used. A bottle having a basis weight of 24 g is placed in both dies at the time of molding to a thickness of 6 from a uniaxially stretched PP film.
The same molding was performed while inserting a 0 micron IML. The properties of the main resins used are shown below. Resin consisting of maleic anhydride-modified LDPE as adhesive, ethylene content 32 mol% as barrier material
Of EVOH was used.

[0066]

[Table 7]

Table 8 shows the obtained results. As a result, it was found that in each case, sufficient drop strength was ensured even when the weight was reduced. When a Ziggler-based catalyst LLDPE having a wide molecular weight distribution is used for the outer layer, the use of a fluidity improving material suppresses the surface roughness to some extent and provides a practical level of appearance. However, in order to completely perform the air hole sealing after leaving the molding machine, it was necessary to increase the set temperature condition by about 30 ° C. from the conventional condition (the present invention 9). By using LLDPE having good fluidity for the outer layer, appearance characteristics including transparency, moldability, and air hole sealing properties were as good as conventional LDPE (Invention 7). Further, by using the metallocene catalyst LLDPE having a high fluidity and a relatively low density in the outer layer, it is possible to obtain a bottle having good glossiness in addition to transparency, and in this case, a lubricant having a low surface stickiness is used. Even when the addition amount was reduced to half of the conventional amount, the bottle transportability in the filling line was sufficiently satisfactory (Invention 8).

[0068]

Table 8 Transparency Drop strength Remarks (%) 5 ° C 1.2 m haze Light transmittance Vertical Horizontal Invention 7 13 87 0/200 0/20 Invention 8 10 90 0/200 0/20 Good surface gloss book Invention 9 18 80 0/200 0/20 The surface is slightly cloudy. Air hole seal conditions improved

[0069]

According to the present invention, in a squeeze bottle comprising an inner and outer layer containing an ethylene polymer and an intermediate layer containing a gas barrier resin, at least one of the inner and outer layers has a density of 0. 918 g / cm3 or more, molecular weight distribution (Mw / Mn) is 4.5 or more, and melting point is 11
By forming a layer containing an ethylene / α-olefin copolymer having a temperature of 6 ° C. or higher, the drop strength, rigidity, heat resistance, moldability, and transparency were significantly improved while the weight of the container was reduced. A lightweight squeeze bottle can be provided. In addition, by blending the above-mentioned ethylene / α-olefin copolymer with the regrind or repro of the bottle and using the blend for forming the container wall, the dispersion of the regrind or repro resin is good, and the above-mentioned excellent properties are obtained. Is obtained. Further, according to the present invention,
While the container wall is thinned, the in-mold sticking of the label (IM
L) is possible, and the formation of the logo can be performed smoothly.

[Brief description of the drawings]

FIG. 1 is a side view showing an example of a lightweight squeeze bottle of the present invention.

FIG. 2 is a horizontal partial sectional view showing a label edge portion of FIG. 1 in an enlarged manner.

FIG. 3 is a side view showing another example of the lightweight squeeze bottle of the present invention.

FIG. 4 is a horizontal partial cross-sectional view showing, on an enlarged scale, a case of a logo mark shown in FIG. 3;

FIG. 5 is a sectional view showing an example of a sectional structure of a bottle wall.

FIG. 6 is a sectional view showing another example of the sectional structure of the bottle wall.

FIG. 7 is a sectional view showing still another example of the sectional structure of the bottle wall.

[Explanation of symbols]

1. 1. In-mold label, Logo mark, 3. Bottle 4. 4. label edge; Bottle base material, 6. At the time of logo mark, 7. Adhesive, 8. 8. Barrier material: EVOH, Main material (containing repro), 10. Outer layer material, 11; Barrier material: EVOH composite system.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08L 23/08 B65D 1/00 BF Term (Reference) 3E033 AA01 BA13 BA14 BA15 BA21 BB08 CA03 CA07 CA16 CA18 DA03 DB01 DD01 FA03 4F100 AK01C AK06D AK62A AK62B AK63 AK68D AK69 AL05A AL05B BA03 BA04 BA05 BA06 BA07 BA10A BA10B BA10D BA13 CB00 GB17 JA04A JA04B JA06A JA06B JA07A JA07B J13A JA13B01 J01J01B01 J01B01J01B01

Claims (7)

[Claims] 1. A squeeze bottle comprising an inner layer and an outer layer containing an ethylene polymer and an intermediate layer containing a gas barrier resin, wherein at least one of the inner and outer layers has a density of 0.918 g / cm ³ or more and a molecular weight of Distribution (Mw / M
n) a lightweight squeeze bottle comprising a layer containing an ethylene / α-olefin copolymer having a melting point of at least 4.5 and a melting point of at least 116 ° C. 2. The bottle according to claim 1, wherein the ethylene / α-olefin copolymer has a melt tension of 3 g or more. 3. The method of claim 1, wherein the layer containing the ethylene / α-olefin copolymer comprises a blend of a virgin ethylene / α-olefin copolymer and a bottle regrind. Bottle. 4. The bottle according to claim 3, wherein the regrind is contained in an amount of 5 to 80% by weight. 5. The bottle according to claim 1, wherein the layer containing the ethylene / α-olefin copolymer is provided in a thickness of 30 to 97% of the total thickness of the bottle. Bottle. 6. An inner layer and / or outer layer comprising a low-density polyethylene or ethylene-vinyl acetate copolymer as an inner layer and / or an outer layer containing an ethylene / α-olefin copolymer.
The bottle according to any one of claims 1 to 5, wherein an outermost layer is laminated. 7. A gas barrier resin intermediate layer, an adhesive layer provided on both sides of the gas barrier resin intermediate layer, and an inner layer comprising a blend of a virgin ethylene / α-olefin copolymer and a bottle regrind. And / or outer layer,
The bottle according to any one of claims 1 to 6, wherein the bottle has a layer structure of an innermost layer and an outermost layer made of low-density polyethylene or ethylene-vinyl acetate copolymer.