PACKAGE CONTAINING FLUID

Abstract

A package including a container body containing a fluid with leaving a head space, wherein a container body (1) has an inner surface coated with a lubricating liquid (30) immiscible with a fluid (3), and the lubricating liquid (30) is present as a coating layer interposed between the inner surface and the fluid (3), the lubricating liquid (30) forms a liquid pool at a periphery of an upper end face of the fluid (3) contained in the container body (1) in a state of being held upright, and a contact angle of the lubricating liquid (30) to the inner surface is smaller than the contact angle of the fluid (3) to the inner surface.

Claims

1. A package including a container body containing a fluid with leaving a head space, wherein the container body has an inner surface coated with a lubricating liquid immiscible with the fluid, and the lubricating liquid is present as a coating layer interposed between the inner surface and the fluid, the lubricating liquid for forming the coating layer forms a liquid pool at a periphery of an upper end face of the fluid contained in the container body in a state of being held upright, and a contact angle of the lubricating liquid to the inner surface is smaller than the contact angle of the fluid to the inner surface.

2. The package according to claim 1, wherein the fluid is a viscous substance having a viscosity of not less than 100 mPa.Math.s at 25° C.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0036] FIG. 1: a set of schematic cross-sectional views, one of which showing principal parts of a package of the present invention, and the others showing the parts in a state of discharging a fluid (lower area (slippery surface)).

[0037] FIG. 2: a set of schematic cross-sectional views, one of which showing principal parts of a package of the present invention, and the others showing the parts in a state of discharging a fluid (upper area (peeling surface)).

[0038] FIG. 3: an overall view showing a directly blow-formed bottle as one the most preferable embodiment of a container body of the package of the present invention.

MODE FOR CARRYING OUT THE INVENTION

<Structure and Function of Package>

[0039] The package of the present invention as shown in FIGS. 1 and 2 comprises a container body 1 containing a fluid 3. In particular, as shown in FIGS. 1(A) and 2(A), the container body 1 in an upright state is sealed at the upper end with a sealing foil 5, and appropriately closed with a lid (not shown). A head space 7 is formed between the upper end face of the fluid 3 and the upper end of the container body 1 (sealing foil 5).

[0040] A preferable example of the container body 1 is a directly blow-formed bottle, which is shown in FIG. 3.

[0041] The directly blow-formed bottle (corresponding to the container body 1 in FIGS. 1 and 2) denoted as 10 as a whole in FIG. 3 has a screwed neck portion 11, a body portion wall 15 linked to the neck portion 11 through a shoulder portion 13, and a bottom wall 17 that closes the lower end of the body portion wall 15. An opening at the upper end of the bottle is closed with a sealing member 19 such as an aluminum foil (corresponding to the sealing foil 5 in FIG. 1) after filling with the aforementioned fluid 3 (not shown in FIG. 3), and further screw-equipped with a cap 20 to ensure its sealing property.

[0042] The bottle 10 is used preferably for containing a viscous fluid. The viscous substance contained in the bottle may be discharged by squeezing the bottle at the body portion wall 15.

[0043] An inner surface 1a of the container body 1 (for instance, a directly blown bottle 10 in FIG. 3) shown in FIGS. 1 and 2 can be a roughened surface or a flat smooth surface. In FIGS. 1 and 2, the surface is indicated as a flat smooth surface. The flat smooth surface 1a is coated with a lubricating liquid 30 to improve the slipping property to the fluid 3, and the lubricating liquid 30 is interposed between the fluid 3 and the inner surface 1a of the container body 1.

[0044] In the present invention, the lubricating liquid 30 and the fluid 3 are selected so that the contact angle of the lubricating liquid 30 to the inner surface 1a is smaller than the contact angle of the fluid 3 to the inner surface 1a.

[0045] In the aforementioned package of the present invention having a basic structure as described above, a liquid pool 31 of the lubricating liquid 30 is formed at the periphery of the upper end face of the fluid 3 in the container body 1 in an upright state, as shown in FIGS. 1(A) and 2(A). Namely, in the upright state, the lubricating liquid 30 that coats the inner surface 1a in the area to correspond to the head space 7 located above the fluid 3 may flow down to form the liquid pool 31 of the lubricating liquid 30. For this reason, the thickness of the lubricating liquid 30 is decreased on the inner surface 1a′ in the area corresponding to the head space 7 in comparison with the thickness of the lubricating liquid 30 in the area interposed between the fluid 3 and the inner surface 1a of the container body.

[0046] In the present invention, the thus formed liquid pool 31 serves to stably exhibit an excellent slipping property in the discharge of the fluid 3.

[0047] For instance, in discharging the fluid 3, a sealing foil 5 is peeled off, and then, the container body 1 is tilted as shown in FIG. 1(B), so that the lubricating liquid 30 forming the liquid pool 31 flows down on the inner surface 1a (1a′) in the area corresponding to the head space 7 and reaches the upper end part of the container body 1. The fluid 3 is discharged in this state. At this time, the lubricating liquid 30 that forms the liquid pool 31 flows down to increase the thickness of the film on the inner surface 1a′ of the area corresponding to the head space 7, as shown in FIG. 1(C). The fluid 3 may be discharged together with the lubricating liquid 30 while keeping in contact with the thickened film 30a of the lubricating liquid 30, or may slide on the thickened film 30a of the lubricating liquid 30, whereby the container inner surface can stably exhibit an excellent slipping property to the fluid 3.

[0048] After discharging a predetermined amount of the fluid 3, the container body 1 is returned to its upright state. In this state, since the lubricating liquid 30 is subjected to a smaller flow resistance, it rapidly flows down inside the container body 1, and the remaining fluid 3 may rapidly fall inward the container body 1 together with the lubricating liquid 30.

[0049] After the discharge of the fluid 3, the container body 1 is still held in an upright state. The lubricating liquid 30 that coats the inner surface of the area corresponding to the head space 7 falls little by little over time, thereby reconstituting the liquid pool 31 on the upper end face periphery of the fluid 3 as shown in FIG. 1(A). As a result, the fluid 3 can be discharged next time as rapidly as the initial discharge.

[0050] In the package of the present invention, the contact angle of the lubricating liquid 30 to the inner surface 1a as an underlying layer of the container body 1 is smaller than the contact angle of the fluid to the inner surface 1a, namely, the flow resistance of the lubricating liquid 30 is extremely small. As a result, the fluid 3 contained in the container body 1 may be discharged rapidly from the container body 1 together with the lubricating liquid 30. Even if the fluid 3 is a viscous substance, it may be discharged from the container body 1 without remaining therein.

[0051] On the other hand, at the interface where the fluid 3 is peeled off from the container body 1 (i.e., the upper area of the inner surface 1a of the container body 1) at the time of tilting the container body 1 to discharge the fluid 3, gravity works first in the direction in which the fluid 3 leaves the container body 1 as shown in FIG. 2(B). At this time, the tilting applies a force to the liquid pool 31 to flow on the inner surface 1a down to the upper end part of the container body 1, while the liquid pool 31 gradually flows onto the inner surface 1a to fill the gap formed by the move of the fluid 3. As a result, the lubricating liquid 30 enters the gap between the fluid 3 and the container body 1, and thus, the fluid 3 and the container body 1 are easily separated from each other as shown in FIG. 2(C). When the liquid pool 31 is small or there is no liquid pool, the liquid cannot flow into the gap between the fluid 3 and the container body 1 as mentioned above, and this may degrade considerably the peeling property.

[0052] As mentioned above with reference to FIGS. 1 and 2, formation of a liquid pool of the lubricating liquid improves both the slipping property and peeling property, thereby enabling stable and smooth discharge.

<Container Body 1>

[0053] In the present invention, the container body 1 has an inner surface 1a as a flat smooth surface. Alternatively, the inner surface can be roughened as long as the aforementioned behavior is not hindered.

[0054] The materials to form the inner surface 1a of the container body 1 are not limited in particular, and they can be selected from thermoplastic resins, thermosetting resins, glass and metals, depending on the use and the contents. The inner surface is preferably formed of a thermoplastic resin from the viewpoint of reducing excessive consumption of the lubricating liquid 30.

[0055] The thermoplastic resins are not limited in particular as long as they can be formed into container shapes. Usually, it is preferably selected from olefin resins such as low-density polyethylene, linear low-density polyethylene, medium- or high-density polyethylene, polypropylene, poly(1-butene), and poly(4-methyl-1-pentene), copolymer resins of these olefins; and polyester resins such as polyethylene terephthalate, polyethylene naphthalate, and polyethylene terephthalate/isophthalate. These are preferably used also for forming an outer surface of the container.

[0056] In a case of using this container body 1 as a directly blow-formed bottle as shown in FIG. 3, olefin resins as represented by the low-density polyethylene and the linear low-density polyethylene are used preferably since they are suitable for squeezing out the contents.

[0057] The inner surface 1a of the container body 1 to be formed of the thermoplastic resin is not necessarily roughened. For this reason, there is no necessity of blending the thermoplastic resin with an inorganic material or the like that serves as a roughening agent. Alternatively, this inner surface 1a can comprise both a roughened surface and a flat smooth surface.

[0058] It is necessary to make the fluid start moving at the time of tilting the container and discharging the content. For this purpose, the surface to exhibit the slipping property can be roughened while the surface to exhibit the peeling property can be smoothened. In other words, the lower surface can be a roughened surface while the surface opposite to the lower surface can be a flat smooth surface.

[0059] For making the roughened surface, any inorganic materials such as silica to serve as a roughening agent may be blended in the resin of the inner surface. The fine particles to be blended as the aforementioned roughening agent are not limited in particular as long as their average particle diameter is within the aforementioned range. Representative examples thereof include: particles of metal oxides such as titanium oxide, alumina, and silica; particles of carbonates such as calcium carbonate; particles based on carbon such as carbon black; and organic fine particles formed of polymethyl(meth)acrylate, polyethylene, and silicone as represented by polyorganosilsesquioxane. These particles may be subjected to hydrophobic treatment with a silane coupling agent, a silicone oil or the like. In the present invention, the process can be performed also by extrusion such as direct blow forming as long as the particle diameter can be kept after melt forming. Examples of materials preferably used for this purpose include fine particles subjected to hydrophobic treatment, particularly particles of hydrophobic silica, cured polymethyl methacrylate, ultra-high molecular weight polyethylene, polyorganosilsesquioxane, and silicone.

[0060] Further in the present invention, the container body 1 may have a single layer structure of the aforementioned thermoplastic resin or a multi-layered structure of a resin mixed with the aforementioned surface roughening agent.

[0061] For instance, a gas barrier resin layer can be formed as an intermediate layer between the inner surface layer and the outer surface layer of the container body 1, thereby preventing the content from deterioration caused by permeation of a gas such as oxygen.

[0062] Examples of the above-mentioned gas barrier resin include ethylene-vinyl alcohol copolymer (saponified ethylene-vinyl acetate copolymer), aromatic polyamide and cyclic polyolefin. Among them, the ethylene-vinyl alcohol copolymer is the most preferred since it exhibits particularly excellent oxygen barrier property.

[0063] As the above-mentioned ethylene-vinyl alcohol copolymer, a saponified copolymer is preferred, which is obtained by saponifying an ethylene-vinyl acetate copolymer having an ethylene content of 20 to 60 mol %, particularly 25 to 50 mol % so that the saponification degree reaches 96 mol % or more and particularly 99 mol % or more.

[0064] The aforementioned gas barrier resins each can be used by itself or in blends of two or more different types thereof. For improving adhesion to the inner surface layer or the outer surface layer, polyolefins such as polyethylene may be blended in the gas barrier resin in a range not degrading the gas barrier property.

[0065] In a case of providing the gas barrier layer as the intermediate layer, it is preferable to provide an adhesive resin layer between the inner surface layer and the gas barrier layer and between the outer surface layer and the gas barrier layer in order to improve the adhesion between the inner surface layer or the outer surface layer, thereby preventing delamination.

[0066] Adhesive resins that can be used for forming the adhesive layer are known per se, and for instance, they are resins containing a carbonyl group (>C═O) in the main chain or the side chain, in an amount of 1 to 100 meq/100 g, in particular, 10 to 100 meq/100 g. Specific examples of such resins to be used as adhesive resins include: an olefin resin graft-modified with a carboxylic acid such as maleic acid, itaconic acid or fumaric acid or an anhydride thereof, or with an amide or an ester; an ethylene-acrylic acid copolymer; an ionically crosslinked olefin copolymer; and an ethylene-vinyl acetate copolymer.

[0067] Furthermore, the multi-layered structure may have a reproduced layer obtained from a virgin resin which is used for forming the inner layer or the outer layer and which is mixed with a scrap resin such as burrs generated during formation of this container body 1.

[0068] The respective layers are set to have thickness known per se so that the properties required for the layers are to be exhibited. Moreover, additives such as an antioxidant, a surfactant and a colorant can be added to the resins for forming the respective layers as appropriate without impairing the properties of the respective layers.

[0069] The shape of the container body 1 is not limited in particular as long as the liquid pool 31 can be formed by coating the inner surface 1a with the lubricating liquid 30, and the container body 1 may have a shape of a bottle or a cup.

[0070] The container body 1 may be produced by forming a preform through extrusion-forming of a resin for forming the aforementioned respective layers and then forming the preform into the predetermined container shape by post-processes such as blow-forming, a plug-assisted forming, and vacuum forming.

[0071] Particularly in the present invention, it is the most preferable that this container body 1 has a shape of a directly blow-formed bottle suitable for discharging the viscous fluid as shown in FIG. 3. The directly blow-formed bottle may be produced by forming a tube-like preform by extrusion-forming, pinching off to close the preform at one end, and blowing a fluid such as air into this preform to shape it as a bottle.

<Lubricating Liquid 30 and Fluid 3>

[0072] In the package of the present invention, comprising the container body 1 containing the aforementioned fluid 3, the thus formed inner surface 1a of the container body 1 is coated with the lubricating liquid 30, and then, the container body 1 is filled with the fluid 3 so as to form the head space 7.

[0073] The lubricating liquid 30 having an appropriate surface property is selected corresponding to the type of the fluid 3 to be contained in the container body 1. Therefore, the lubricating liquid 30 is required to be immiscible with the fluid 3. Here, a liquid being immiscible with the fluid 3 means that the liquid may not be dispersed instantly even when it gets into contact with the fluid 3 but may remain as the lubricating liquid 30. Further, the lubricating liquid 30 is required to be a non-volatile liquid having a small vapor pressure under an atmospheric pressure, for instance, a liquid having a high boiling point of not lower than 200° C. If a volatile liquid was used for the lubricating liquid 30, the liquid would easily be evaporated and lost over time, and thereby making it difficult to improve the slipping property to the fluid 3.

[0074] Various specific examples can be listed for the lubricating liquid 30, as long as they are the aforementioned liquids having high boiling points and their contact angles to the inner surface 1a are smaller than the contact angle of the fluid 3 to the inner surface 1a. In particular, a lubricating liquid 30 having a surface tension considerably different from that of the fluid 3 which slips over the liquid is preferred in the present invention, since the lubricating effect may be greater.

[0075] For instance, when the fluid 3 is water or a hydrophilic substance containing water, a liquid having a surface tension in a range of 10 to 40 mN/m, in particular in a range of 16 to 35 mN/m, is preferably used as the lubricating liquid 30. Representative examples thereof include fluorine-based liquids, fluorosurfactants, silicone oil, fatty acid triglyceride, and various vegetable oils. Preferable examples of the vegetable oils include soybean oil, rapeseed oil, olive oil, rice oil, corn oil, safflower oil, sesame oil, palm oil, castor oil, avocado oil, coconut oil, almond oil, walnut oil, hazel oil, and salad oil. These liquids may be blended in use. Further, the lubricating liquid selected from the aforementioned examples preferably has a high wettability with the inner surface 1a (i.e., the contact angle to the inner surface 1a is small). The lubricating liquid that constitutes the liquid pool 31 may be different from the lubricating liquid that coats the inner surface 1a.

[0076] In the present invention, the contact angle refers to the angle at which a liquid surface meets a solid surface on the interface where three phases of a solid inner surface, a liquid and a gas are in contact with each other.

[0077] In the present invention, it is important that a certain amount of excessive lubricating liquid 30 is contained in order to form a coating layer of the lubricating liquid 30 on the inner surface 1a and to form the liquid pool 31. The excessive lubricating liquid may be added before or after filling with the fluid. Examples of the addition method include spraying, simultaneously extruding with the melting resin, simultaneously injecting with the contents, and bleeding by internal addition. In a case where the lubricating liquid to coat the inner surface 1a of the container body 1 and the lubricating liquid to form the liquid pool 31 are different from each other, the lubricating liquid to form the liquid pool 31 may be provided later as an excess.

[0078] In brief, in the present invention, the lubricating liquid 30 is used to coat the inner surface 1a of the container body 1. Specifically, the coating is provided by applying an excessive amount of lubricating liquid 30 onto the inner surface 1a of the container body 1 so that the liquid pool 31 is formed at the periphery of the fluid 3 facing the head space 7 at the time of filling the container with the fluid 3 (see FIG. 1(A)).

[0079] More specifically, the inner surface 1a′ is entirely coated in advance with the excessive amount of lubricating liquid 30 or, alternatively, the excessive lubricating liquid is fed after filling the container with the fluid. As a result, when the container body 1 filled with the fluid 3 is held in an upright state as shown in FIG. 1(A), the lubricating liquid 30 will drip from the inner surface 1a (1a′) in the area corresponding to the head space 7.

[0080] For this purpose, it may be necessary to spray this lubricating liquid 30 on the entire inner surface of the container body 1. For instance, the application amount may preferably be 0.1 g/m.sup.2 or more, or in a range of about 0.1 to about 10 g/m.sup.2 in average, including the excess. By setting the application amount in this manner, the flat smooth surface 1a will be coated completely with the lubricating liquid 30.

[0081] Therefore, the inner surface 1a may be roughened as long as the liquid pool 31 is formed.

[0082] The lubricating liquid 30 can be sprayed while the container body 1 is held in an upright state or inverted as long as the inner surface 1a can be coated entirely with the excessive amount of lubricating liquid 30.

[0083] After applying the lubricating liquid 30 as mentioned above, the fluid 3 is fed from a predetermined feeding pipe into the interior of the container body 1 that is held in an upright state with its inner surface being coated entirely with the excessive amount of lubricating liquid 30, so that the head space 7 is left unfilled (in some cases, the excessive lubricating liquid may be provided after filling the container with the fluid 3).

[0084] In other words, when the fluid 3 is fed as mentioned above, the lubricating liquid 30 that coats the inner surface 1a (1a′) in the area corresponding to the head space 7 may drip, so that the liquid pool 31 can be formed at the periphery of the upper end face of the fluid 3. As a result, as shown in FIG. 1(A), the thickness of the lubricating liquid 30 is decreased in the area above the liquid pool 31 in comparison with the thickness of the lubricating liquid 30 interposed between the side surface of the fluid 3 and the flat smooth surface 1a, as described above.

[0085] The fluid 3 used for the filling has a surface tension considerably different from that of the lubricating liquid 30 (i.e., its contact angle to the inner surface 1a is larger than that of the lubricating liquid 30). Specifically, the fluid 3 may be a viscous fluid having a viscosity of not less than 100 mPa.Math.s at 25° C. Specific examples thereof include ketchup, aqueous paste, honey, various sauces, mayonnaise, mustard, dressing, jam, chocolate syrup, cosmetic liquids such as milky lotion, liquid detergent, shampoo, and rinse. That is, a suitable lubricating liquid 30 is used corresponding to the type of the fluid 3 to form the liquid pool 31, so that the viscous fluid 3 can be rapidly discharged by tilting or inverting the container.

[0086] Preferred examples of the fluid 3 include hydrophilic substances that contain water, such as ketchup, various sauces, honey, mayonnaise, mustard, jam, chocolate syrup, milky lotion and the like.

[0087] The lubricating liquid 30 is preferably selected from oily liquids that have been approved as food additives, such as silicone oil, glycerin fatty acid ester, and edible oil.

[0088] After filling the container with the fluid 3 such that the head space 7 is formed and also forming the liquid pool 31 of the lubricating liquid 30 as mentioned above, the sealing foil 5 is attached by heat sealing and the lid is suitably attached to provide the package of the present invention.

EXAMPLES

[0089] The present invention will be described below by referring to Examples.

[0090] The method of measurements conducted in Examples below for measuring respective characteristics and physical properties, and the container bodies (bottles) are as mentioned below.

<Container Body>

[0091] A multi-layered directly blow-formed bottle having the following layer constitution and capacity of 500 mL was formed by a known method and used in experiments below.

Bottle A: directly blow-formed multi-layered bottle having 9 layers of 5 types

[0092] Layer constitution: inner layer/adhesive layer/liquid diffusion prevention layer/adhesive layer/main layer/adhesive layer/oxygen barrier layer/adhesive layer/outer layer

[0093] Inner layer: low-density polyethylene

[0094] Adhesive layer: acid-modified polyethylene

[0095] Liquid diffusion prevention layer: ethylene-vinyl alcohol copolymer (EVOH)

[0096] Main layer: low-density polyethylene (LDPE)

[0097] Oxygen barrier layer: ethylene-vinyl alcohol copolymer (EVOH)

[0098] Outer layer: low-density polyethylene (LDPE)

Bottle B: directly blow-formed multi-layered bottle having 9 layers of 5 types

[0099] Layer constitution: inner layer/adhesive layer/liquid diffusion prevention layer/adhesive layer/main layer/adhesive layer/oxygen barrier layer/adhesive layer/outer layer

[0100] Inner layer: polyethylene blended with 5% by weight of silica 5 μm in average particle diameter

[0101] Adhesive layer: acid-modified polyethylene

[0102] Liquid diffusion prevention layer: ethylene-vinyl alcohol copolymer (EVOH)

[0103] Main layer: low-density polyethylene (LDPE)

[0104] Oxygen barrier layer: ethylene-vinyl alcohol copolymer (EVOH)

[0105] Outer layer: low-density polyethylene (LDPE)

<Lubricating liquid>

[0106] Medium chain fatty acid triglyceride (MCT)

[0107] Surface tension: 28.8 mN/m (23° C.)

[0108] Viscosity: 33.8 mPa.Math.s (23° C.)

[0109] Boiling point: 210° C. or higher

[0110] Flash point: 242° C. (reference value)

[0111] The surface tension of the liquid was measured at 23° C. using a solid-liquid interface analysis system DropMaster 700 (manufactured by Kyowa Interface Science Co., Ltd.). The density of the liquid required for the surface tension measurement was measured at 23° C. using a density/specific gravity meter DA-130 (manufactured by Kyoto Electronics Manufacturing Co., Ltd.). Further, the viscosity of the liquid was measured at 23° C. using a tuning-fork vibration viscometer SV-10 (manufactured by A&D Company Limited).

<Fluid>

[0112] Mayonnaise-type viscous food

[0113] Viscosity: 499 Pa.Math.s (0.1 sec.sup.−1) [0114] 94 Pa.Math.s (1 sec.sup.−1) [0115] 0.30 Pa.Math.s (1000 sec.sup.−1)

[0116] For the viscosity measurement, a rheometer (ARES manufactured by TA Instruments) was used. The values measured by the steady flow method at the geometry of the parallel plate with a gap 0.5 mm were indicated.

<Formation of Liquid Pool of Lubricating Liquid>

[0117] The bottle was filled with 200 g of the fluid, and several drops of the lubricating liquid (MCT) was applied to the periphery of the upper end face of the fluid so as to form a liquid pool. Further, the lubricating liquid (MCT) was dripped only a part of the periphery (about one-fourth area of the periphery) to form a liquid pool for the purpose of a peeling property test as described later.

<Test of Slipping Property to Fluid>

[0118] After forming a liquid pool of the lubricating liquid, the slipping property to the content was evaluated. Specifically, a bottle in an upright state at room temperature (25° C.) was tilted by about 45° so as to evaluate the slipping property to the content based on the time required for the content to completely slide down toward the mouth portion of the bottle. The criteria for evaluation are as follows.

[0119] ∘: time for sliding down completely is less than 5 minutes

[0120] Δ: time for sliding down completely is 5 minutes or more and less than 10 minutes

[0121] x: time for sliding down completely is 10 minutes or more

<Test of Peeling Property to Fluid>

[0122] A bottle provided partially with a liquid pool by the aforementioned method was used. In room temperature (25° C.), the bottle in an upright state was tilted by about 45° so that the liquid pool was positioned above, thereby to evaluate the peeling property to the contents. The evaluation criteria are as follows.

[0123] ∘: peeling instantly

[0124] x: no peeling, or peeling in 10 minutes or more

<Experimental Example 1a

[0125] The bottle A (directly blow-formed multi-layered bottle having 9 layers of 5 types) was prepared as the container body.

[0126] To the inner surface of the bottle A, medium chain fatty acid triglyceride as a lubricating liquid of the amount shown in Table 1 was applied by an air-spray method using an air brush. The bottle having the inner surface coated with the lubricating liquid was used to form the liquid pool of the aforementioned lubricating liquid and to conduct the tests for the slipping property to the fluid and the peeling property to the fluid. The results are shown in Table 1. Here, the contact angle of the lubricating liquid to the low-density polyethylene surface is smaller than that of the fluid to the low-density polyethylene surface.

Experimental Example 2

[0127] The slipping property and peeling property to the fluid were tested similarly to Experimental example 1 except that the liquid pool of the lubricating liquid was not formed. The results are shown in Table 1.

Experimental Example 3

[0128] The bottle B (directly blow-formed multi-layered bottle having 9 layers of 5 types) was prepared as the container body, through a process similar to that of Experimental example 1, except that a low-density polyethylene blended with 5% by weight of silica 5 μm in average particle diameter was used as the resin for the inner layer.

[0129] This bottle was evaluated as described above, and the results are shown in Table 1.

Experimental Example 4

[0130] The slipping property and peeling property to the fluid were tested similarly to Experimental example 1 except that the inner surface of the bottle A was coated with the lubricating liquid and the liquid pool of the lubricating liquid was not formed. The results are shown in Table 1.

TABLE-US-00001 TABLE 1 Coating Formation of amount of liquid pool of lubricating lubricating Slipping Peeling Bottle liquid (g/m.sup.2) liquid property property Exptl. Bottle A 3 Yes ∘ ∘ Ex. 1 Exptl. Bottle A 3 No Δ x Ex. 2 Exptl. Bottle B 3 Yes ∘ ∘ Ex. 3 Exptl. Bottle A — No x x Ex. 4 * Exptl. Ex.: Experimental example

[0131] The inner surfaces of the bottles in Experimental examples 1-3 were coated with the lubricating liquid. Both the slipping property and peeling property were favorable in Experimental examples 1 and 3 where the liquid pools of the lubricating liquid were formed, while the same properties were inferior in Experimental example 2 where no liquid pool was formed.

[0132] Both the slipping property and the peeling property were poor in Experimental example 4 where neither a coating of the lubricating liquid nor a liquid pool was formed.

[0133] The results demonstrate that the coating with the lubricating liquid and forming a liquid pool serve to improve both the slipping property and the peeling property, and the synergy of these properties facilitates discharge of the contents.

DESCRIPTION OF REFERENCE NUMERALS

[0134] 1: container body [0135] 1a: inner surface of container body 1 [0136] 3: fluid [0137] 5: sealing foil [0138] 7: head space [0139] 30: lubricating liquid [0140] 31: liquid pool