JPH08238667A - Vessel, manufacture thereof and preform - Google Patents

Abstract

PURPOSE: To improve the barrier properties for oxygen, carbon dioxide or odor by forming a resin film made of coating agents of polyvinyl alcohol, vinylidene chloride or ethylene-vinyl alcohol copolymer on the surface of a vessel. CONSTITUTION: A preform 1 for molding a vessel is formed of a threaded part 2 protruding to the outside in a pair of molds 9 and 10, a flange 3 supported to the upper edges of both the molds 9, 10, and a cylindrical body 4 with a bottom biaxially oriented by blowing compressed air to be expanded in a vessel shape. A resin film made of any of coating agents of polyvinyl alcohol, vinylidene chloride or ethylene-vinyl alcohol copolymer or a composite material thereof is formed on the outer periphery of the body 4. Thereafter, compressed air is supplied into the interior while orienting the preform 1 by an orientation rod 11, and hence a vessel having a resin film 8' on the outer periphery, i.e., a plastic bottle 7 is molded.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin coating container having excellent gas barrier properties such as oxygen barrier property, carbon dioxide barrier property and odor barrier property, and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, plastic containers are used in various containers because they are lighter in weight than glass and have excellent impact resistance.

In particular, polyester bottles made by stretch blow molding, especially polyethylene terephthalate (PE
T), and polyolefin bottles, especially polypropylene (pp) bottles, have excellent physical properties (transparency, gloss, lightness, appropriate rigidity, etc.), such as carbonated beverages, seasonings, cosmetics, Widely used as a container for liquid detergent, etc.

[0004]

However, the stretch-blown bottles made of polyethylene terephthalate or polypropylene are still insufficient in gas barrier property. In order to improve such a point, there is a method of wrapping a film having excellent gas barrier properties such as ethylene vinyl alcohol (EVOH) and nylon (Ny). Such a method has a problem that the machine is complicated, a range of molding conditions is narrowed, and a cost is increased.

The present invention has been made by paying attention to such problems, and has an oxygen barrier property, a carbon dioxide barrier property,
It is an object of the present invention to provide a container having excellent odor barrier properties and less labor, a method for producing the same, and a preform used in the method.

[0006]

In order to solve the above-mentioned problems, the container according to claim 1 of the present invention is characterized in that a resin coating film having a gas barrier property is formed on the surface thereof.

According to a second aspect of the present invention, in the container according to the first aspect, the resin coating is any one of a polyvinyl alcohol type coating agent, a vinylidene chloride type coating agent, and an ethylene vinyl alcohol copolymer type coating agent. Is a single substance or a composite of these.

The container according to claim 3 of the present invention is the container according to claim 2, wherein the resin coating contains alkoxide or an alkoxide hydrolyzate within a range from 1% by weight to 70% by weight. It is characterized by being.

The container according to claim 4 of the present invention is the container according to claim 3, characterized in that the metal of the alkoxide is either silicon or aluminum.

According to a fifth aspect of the present invention, in the method for producing a container, the surface of the container is subjected to an activation treatment for enhancing chemisorption, and then 1 weight of a resin having a gas barrier property or an alkoxide or an alkoxide hydrolyzate is used. % Concentration to 70% by weight
It is characterized by forming a film of any of the resins contained within the range up to the concentration.

Further, the preform of claim 6 of the present invention is a preform for molding the container of claims 1 to 4, characterized in that a resin coating having a gas barrier property is formed on the surface. And

The container of claim 7 of the present invention is characterized in that a gas barrier resin coating is formed on the surface by stretch-blow molding the preform of claim 6.

In the method for producing a container according to claim 8 of the present invention, a resin film having gas barrier property or an alkoxide or an alkoxide hydrolyzate is obtained after an activation treatment for enhancing chemisorption is performed on the surface of the preform. Is formed in a range of 1 wt% to 70 wt% concentration, and then the preform is heated and stretch blown.

[0014]

According to the container and the method for manufacturing the container of the present invention, since the resin film is formed or the metal is bonded to the resin, the gas barrier property is improved.
In particular, according to the container formed by stretch blow molding of the preform, when the preform is stretch blow molded, the resin film is also stretched and the lattice defects are narrowed, and the lattice spacing is narrowed by the oriented crystals, so that the gas barrier property is reduced. Is improved. In addition, PVA and EVOH have improved water resistance due to oriented crystals, so that the gas barrier property does not deteriorate due to water supply. When the alkoxide or the alkoxide hydrolyzate is contained in the crystal, the gas barrier property is further improved.

According to the preform of claim 6 and the manufacturing method of claims 7 to 8 of the present invention, since the container is formed by stretch blow molding of the preform, the labor for manufacturing the container is reduced, and the laminating method is used. Although the manufacturing time is shorter and the manufacturing cost is lower than that of, it is possible to obtain a container having a sufficient gas barrier property.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A resin coating container and a manufacturing method thereof according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a cross sectional structure of a preform according to an embodiment of the present invention.

This preform 1 forms a plastic bottle by being held in a pair of molds that are opened and closed and stretched and blown. The preform 1 is molded from the edge of the upper part of the mold on the side of the air blowing port. Screw part 2 protruding outside the mold
And a flange portion 3 supported by the edge portion of the die on the side of the air blowing port to play a role of supporting the preform during stretch molding, and is blown with compressed air to be biaxially stretched to expand into a plastic bottle shape. It is composed of a bottomed cylindrical body 4. A resin coating 5 having an excellent gas barrier property is formed on the surface of the body portion 4 of the plastic 1 (the outer surface of the cylindrical portion in this embodiment).

The material of the preform 1 may be any polymer compound that can be stretch blow molded, and specifically, polyester resin such as polyethylene terephthalate (PET) and polyethylene naphthalate, polypropylene (P
P), polyethylene (PE), olefin resin such as cyclic polyolefin, polyacrylonitrile, polycarbonate (PC), low-density polyethylene or high-density polyethylene, polyvinyl chloride, and other resins such as single or composite resins. . The preform 1 may also contain known additives such as ultraviolet absorbers, plasticizers, lubricants, colorants, crystal nucleating agents, antistatic agents, etc. in these polymer compounds. . The method of molding the preform 1 includes injection molding, extrusion molding, compression molding, and machining, but a combination of these may be used.

When the gas barrier resin coating 5 is formed on the preform 1, the gas barrier resin is chemically adsorbed on the surface of the cylindrical body 4 having a bottom and having a bottom. , Perform activation processing. As a method of this activation treatment, there are a flame treatment for applying a flame F, a corona treatment by corona discharge, an ozone treatment and the like as shown in FIG. During the frame processing of the preform 1, the flame is applied while rotating the preform 1 around the center line extending in the coaxial direction. By this, preform 1
The entire peripheral portion of the body portion 4 is activated.

After the activation of the preform 1, the preform 1 is dipped in a liquid tank 6 containing the coating agent 5 as shown in FIG. 3 to apply the coating agent 5 on the surface of the preform 1. The coating method of the coating agent 5 includes dipping, spraying, brushing and the like.

As the coating agent 5 for forming the resin film (see FIG. 4), polyvinyl alcohol type coating agent (PVA), ethylene vinyl acetate alcohol copolymer type coating agent (EVOH), vinylidene chloride type coating agent (PVDC) ). These coating agents 5 enable stretch blow molding after coating and improve oxygen barrier properties, carbon dioxide barrier properties, and odor barrier properties. Polyvinylidene chloride (PVDC) is also excellent in water vapor barrier properties in addition to the above gas barrier properties.

The coating agent 5 contains an alkoxide or an alkoxide hydrolyzate, and the alkoxide or the alkoxide hydrolyzate contained in the coating agent is contained in a concentration of 1% by weight to 70% by weight.

The alkoxide contained may be tetraethyl orthosilicate (Si (OC ₂ H ₅ ) ₄ ), triisopropylaluminum, (Al (OC ₃ H ₇ ) ₃ ), or the like, of the general formula M (OR) n (M is Si , Al, Zr, and other metals, and R is an alkyl group). Among them, the metal M is S
i and Al have excellent alkoxide characteristics.

The amount of the alkoxide or alkoxide hydrolyzate added varies depending on the draw ratio, the type of coating agent to be applied, etc. and is not generally determined, but the uniformity of the coating film 8'of the blow bottle 7 obtained after molding is From the point, 70% or less is preferable, and 40% is more preferable.
It is the following. Also, depending on the thickness of the coating film 8'to be formed, the gas barrier property of the blow bottle is improved only by adding a small amount of alkoxide or alkoxide hydrolyzate, so the lower limit may be any percentage, but more It is preferably 5% or less.

PVA, EVOH, etc., swell when absorbing water and their gas barrier properties deteriorate, but the preform 1 is coated with the coating agent 5 in advance, and the preform 1
By stretch-blow molding, it is possible to suppress deterioration of gas barrier properties.

The coating agent 5 includes a polyvinyl alcohol-based coating agent (hereinafter, PVA) containing no alkoxide, an ethylene-vinyl alcohol copolymer-based coating agent (EVOH), a vinylidene chloride-based coating agent (PVDC), and the like. Even with a coating agent containing no alkoxide, the activation treatment is performed to such an extent that the surface of the preform 1 can be coated.

The coating agent 5 containing an alkoxide or a hydrolyzate of an alkoxide is preferably a coating agent capable of stretch blow molding after coating on a preform, and examples thereof include PVA, EVOH and PVDC.

The coating agent 5 is excellent in gas barrier properties such as oxygen barrier property, carbon dioxide barrier property, odor barrier property (PVDC is also excellent in water vapor barrier property), and thus the coating agent may be coated alone.
It is preferable to contain an alkoxide or an alkoxide hydrolyzate.

The preform 1 coated with the coating agent 5 is first dried before being stretched and blown by heating the preform 1 coated with the coating agent by infrared radiation from an infrared heater or heating by an oven. While the body part 4 of the preform 1
Increase the surface temperature of 100 ° C to 150 ° C. After the temperature of the preform 1 is raised, the preform 1 is gradually cooled. If the material of the preform 1 is polyethylene terephthalate, cool to 70 ° C to 100 ° C, and if the material of the preform 1 is polypropylene, 110 ° C
The temperature is lowered to the stretching temperature of each resin, for example, by cooling to 130 ° C., so that the temperature distribution of the body portion 4 of the preform 1 becomes uniform.

Preform 1 heated to a stretchable temperature
The flange portion 3 is set between a pair of molds 9 and 10 that can be opened and closed, and while being stretched by the stretching rod 11, compressed air is supplied from an air nozzle (not shown) to mold a plastic bottle.

The pressure and speed of the drawing rod 11 depend on the shape of the preform 1 to be drawn and the shape of the final molded product, but usually at a pressure of 3 to 20 Kgf · cm ⁻² and a speed of ^{2 to} 50 cm / s. To move.

The compressed air sets the primary blow pressure and the secondary blow pressure, and the primary blow pressure is 1 to 10 Kgf · c.
m ⁻² , and the secondary blow pressure is about 10 to 40 kg · cm ⁻² . The primary blow pressure and the secondary blow pressure do not necessarily have to be separated, and stretch blow molding can be performed with a single pressure, and the molding method is not limited.

FIG. 5 shows a plastic bottle 7 obtained by stretch blow molding the preform 1 of this embodiment.
The plastic bottle 7 has a resin coating 8 ′ on the outer peripheral surface. This resin coating 8 ′ is stretched with the resin coating 8 coated with the preform 1 when the preform 1 is stretch-blown. Preform 1 by stretching
And the blow bottle 7 is molded, and the molecules of the resin coating 8 of the preform 1 are oriented by stretching and the gap between the resin coatings 8'is reduced, and the resin coating 8'is crystallized by cooling and gas barrier properties. And the strength is improved. Further, since the preform 1 is coated in advance, the coating space can be small and the machine can be made compact.

It is also conceivable that the uncoated preform 1 is stretch-blow molded into a plastic bottle and then subjected to a frame treatment or the like for coating treatment. The coating resin coating may be applied to the inner surface of a plastic bottle or tray or cup. Furthermore, the hot parison method and the cold parison method are also conceivable as a method of coating the coating agent 5 after forming the blow bottle. Further, in the above embodiment,
Although the stretch blow molding method has been described as an example of the container manufacturing method, the container molding method of the present invention is not limited, and a direct blow molding method, an injection molding method, an injection blow molding method used for molding plastics, Any plastic processing method such as an extrusion molding method or a vacuum molding method may be used, and a combination of these may be used.

The material of the container molded by the direct blow molding method, the injection molding method, the injection blow molding method, the extrusion molding method, the vacuum molding method, etc. is, for example, high density polyethylene resin (HDPE) or low density polyethylene resin ( LDPE), linear low-density polyethylene resin (LLDPE), polystyrene (PS),
PP, PET, nylon, polyurethane, etc.
These may be used alone or in combination. These plastics may contain additives such as an ultraviolet absorber, a plasticizer, a lubricant, a coloring agent, a crystal nucleating agent, an antistatic agent and the like.

Examples of containers and the like for improving the gas barrier property include containers such as plastic bottles, plastic tanks, plastic tubes, plastic boxes, plastic cases, and plastic bags.
Plastic sheets, plastic films, plastic panels, etc. are also conceivable.

Next, an experimental example of the resin coating container of the present invention will be described below.

[0039]

[Experimental Example 1] In Experimental Example 1, polyethylene terephthalate (intrinsic viscosity IV = 0.70) was used at a cylinder temperature of 280 °.
C, injection-molded at a mold temperature of 20 ° C, a flange portion having a diameter of 27 mm, a diameter of 25 mm, a body portion length of 108 mm, and a thickness of 3.
A preform having a size of 4 mm and a weight of 21 g was obtained.

The preform was frame-treated to have a wettability of 58 dynes, dipped in the following coating agent, and
An O ₂ / PVA coated preform was obtained.

The coating agent used was 8.3 g of tetraethyl orthosilicate (Si (OC ₂ H ₅ ) ₄ ) and pH.
= 2 hydrochloric acid solution (40 g) was added as a catalyst and hydrolyzed to prepare a SiO ₂ solution having a solid content of 5%. 5% of this solid content
A 5% aqueous solution of polyvinyl alcohol (PVA) was added to the SiO ₂ solution. At this time, the weight ratio of SiO ₂ and PVA was adjusted so that SiO ₂ / PVA = 1/1.

The SiO ₂ / PVA-coated preform was reheated to 110 ° C. and gradually cooled to a uniform preform temperature of 90 ° C. (stretching temperature), and the stretching rod pressure was 7 Kgf · cm ^−2. Stretch blow molding at 0.5 s, primary blow 5 Kgf · cm ^-2 3 s, longitudinal draw ratio 1.3 times, transverse draw ratio 2.6 times, bottle height 150
A 300 ml SiO ₂ / PVA coated blow bottle having a diameter of 65 mm and a diameter of 65 mm was obtained.

The blow bottle thus obtained has a transparent appearance, a uniform coating agent, and a wall thickness of 0.6 mm.
It became a container. The results of measuring the oxygen permeability of this blow bottle are shown in Table 1.

[0044]

Experimental Example 2 In Experimental Example 2, the same preform as in Experimental Example 1 was used. This preform was subjected to stretch blow molding without coating treatment to obtain a stretch blow container without coating treatment. This performs frame processing blow bottle, the wetting degree 60 dynes, immersed in SiO ₂ / EVOH coating having Si5%, SiO ₂ /
An EVOH coated blow bottle was obtained. The results of measuring the oxygen permeability of this blow bottle are shown in Table 1.

[0045]

Experimental Example 3 In Experimental Example 3, polypropylene (melt index MI = 8, ethylene content = 4%) was injection-molded at a cylinder temperature of 200 ° C. and a mold temperature of 150 ° C., and had the same shape as that of Example 1. 15 g of preform was obtained.

Frame processing is performed on this preform,
Al ₂ O ₃ with a wettability of 57 dynes and 20% Al content
/ PVDC coating agent, Al ₂ O ₃ / PVDC
I got a coating preform. This Al ₂ O ₃ / PV
Reheat DC coating preform to 140 ° C
(Reheating temperature), the temperature of the preform is gradually cooled to a uniform preform temperature of 115 ° C, the drawing rod pressure is 7 kgfcm ^-2 , and the primary blow pressure is 5 kgfcm.
^-2 , 0.5 s, secondary blow pressure is 15 Kgf · cm ^-2 3
s stretch blow molding. As a result, the longitudinal stretching ratio was 1.
A 300 ml Al ₂ O ₃ / PVDC coating blow bottle having a size of 3 times, a lateral draw ratio of 2.6 times, a bottle height of 150 mm and a diameter of 65 mm was obtained. The stretched blow bottle thus obtained had a uniform coating layer, a transparent appearance, and a thickness of 0.6 mm.

[0047]

[Experimental Example 4] In Experimental Example 4, polystyrene (PS) (melt index MI = 20) was used at a cylinder temperature of 200 °.
C, injection molding at a mold temperature of 25 ° C, diameter 100 mm,
A cup having a height of 50 mm and a wall thickness of 0.6 mm was obtained. The cup thus obtained had a uniform coating layer and a transparent appearance. The results of measuring the oxygen permeability of this container are shown in Table 1.

[0048]

Experimental Example 5 In Experimental Example 5, high density polyethylene (HD
PE) (melt index MI = 2) was subjected to direct blow molding at a cylinder temperature of 200 ° C. and a mold temperature of 20 ° C. to obtain a blow bottle having a diameter of 80 mm, a height of 100 mm and a wall thickness of 0.3 mm. This blow bottle was frame-treated to give a wettability of 60 ° dyne, and contained 60% Si.
It was immersed in an O ₂ / PVA coating agent to obtain a SiO ₂ / PVA coating blow bottle. The results of measuring the oxygen permeability of this blow bottle are shown in Table 1.

[0049]

Comparative Example 1 Next, the same preform as in Experimental Example 1 was subjected to stretch blow molding without being subjected to coating treatment to obtain an uncoated stretch blow bottle similar to that in Experimental Example 1. The results of measuring the oxygen permeability of this blow bottle are shown in Table 1.

[0050]

Comparative Example 2 Next, the same preform as in Experimental Example 3 was stretch blow-molded without coating treatment, and an uncoated stretch blow bottle similar to Experimental Example 3 was obtained as Comparative Example 2. Table 1 shows the oxygen permeability results of the blow bottle of Comparative Example 2.

[0051]

Comparative Example 3 Furthermore, in Comparative Example 3, the results of measuring the oxygen permeability of Comparative Example 3 without coating the cup obtained by injection molding of Experimental Example 4 are shown in Table 1.

[0052]

[Comparative Example 4] As Comparative Example 4, the oxygen permeability of this container was measured without coating the bottle obtained by the direct blow molding of Experimental Example 5 and the results are shown in Table 1.
Shown in

[0053]

[Table 1] Bottle material Volume (l) Coating agent Metal concentration Oxygen permeability (ml / pkg · day) Experimental example 1 PET 0.3 SiO ₂ / PVA 50% 0.02 Experimental example 2 PET 0.3 SiO ₂ / EVOH 5 0.02 Comparative example 1 PET 0.3 0.10 Experimental Example 3 PP 0.3 Al ₂ O ₃ / PVDC 20 0.20 Comparative Example 2 PP 0.3 0.88 Experimental Example 4 PS 0.35 Al / PVA 70 0.15 Comparative Example 3 PS 0.35 1.22 Experimental Example 5 HDPE 0.5 SiO ₂ / PVA 60 0.54 Comparative Example 4 HDPE 0.5 2.35

[0054]

Experimental Example 6 Next, as an experimental example in which the coating agent did not contain alkoxide, polyethylene terephthalate (I
V = 0.70), cylinder temperature 280 ° C, mold temperature 2
Injection molded at 0 ° C, flange 27mm in diameter, diameter 25mm body length 108mm, thickness 3.4mm, weight 2
1 g of preform was obtained. The preform was frame-treated to have a wettability of 58 dynes and dipped in a 5% PVA aqueous solution to obtain a PVA-coated preform.

This PVA-coated preform was reheated to 110 ° C. (reheating temperature), gradually cooled to a uniform preform temperature of 90 ° C. (stretching temperature), and the stretching rod pressure was 7 Kgf · cm. Stretch blow molding was performed at ^-2 0.5 s and a primary blow pressure of 5 Kgf · cm ^-2 3 s. As a result, the longitudinal stretching ratio is 1.3 times and the lateral stretching ratio is 2.
6 times, bottle height 150mm, diameter 65mm 300m
1 PVA coated stretch blow bottle was obtained. The stretch-blown bottle thus obtained has a transparent appearance,
The coating agent was also uniform and the container had a wall thickness of 0.6 mm. The results of measuring the oxygen permeability of this container are shown in Table 1.

[0056]

[Experimental Example 7] The same preform as in Experimental Example 1 was subjected to stretch blow molding without coating treatment to obtain a stretch blow bottle without coating treatment. Frame processing is applied to this blow bottle to obtain a wetness of 60 dynes, and EVO
It was dipped in the H coating agent to obtain an EVOH coating bottle. The results of measuring the oxygen permeability of this container are shown in Table 1 as Experimental Example 7.

[0057]

[Experimental Example 8] As Experimental Example 8, polypropylene (melt index MI = 8, ethylene content = 4) was used.
%) Is injection-molded at a cylinder temperature of 200 ° C and a mold temperature of 150 ° C.
mm body length 135 mm, thickness 3.2 mm, weight 23
g preform was obtained. The preform was subjected to a frame treatment to obtain a wettability of 57 dynes, which was dipped in a PVDC coating agent to prepare a PVDC coated preform.

The PVDC-coated preform was reheated to 140 ° C. (reheating temperature) and gradually cooled to a uniform preform temperature of 115 ° C. (stretching temperature).
Stretching rod pressure was 7 Kgf · cm ⁻² , primary blow pressure was 5 Kgf · cm ⁻² , 0.5 s, and secondary blow pressure was 15 Kgf · cm ⁻² 3 s. 2.1 times, lateral draw ratio 2.6 times,
A 1000 ml PVDC coated stretch blow bottle having a bottle height of 250 mm and a diameter of 78 mm was obtained.

The stretched blow bottle thus obtained has a uniform coating layer, a transparent appearance and a thickness of 0.3 mm.
It became a thing. The results of measuring the oxygen permeability of this container are shown in Table 1.

[0060]

Comparative Example 5 As Comparative Example 5, the same preform as in Experimental Example 6 was subjected to stretch blow molding without coating treatment to obtain an uncoated stretch blow bottle. The results of measuring the oxygen permeability of the blow bottle of Comparative Example 5 are shown in Table 1.

[0061]

[Comparative Example 6] In Comparative Example 6, the same preform as in Comparative Example 5 was not subjected to coating treatment, stretch blow molding was performed, and the blow bottle was subjected to flame treatment to a wettability of 58 dynes, and a 3% PVA aqueous solution was used. Example 7
A coating blow bottle with the same initial oxygen permeability was prepared. The results of measuring the oxygen permeability of the blow bottle of Comparative Example 6 are shown in Table 1.

[0062]

Comparative Example 7 As Comparative Example 7, the same preform as in Experimental Example 7 was stretch blow-molded without coating treatment to obtain an uncoated stretch-blowing container. The results of measuring the oxygen permeability of this container are shown in Table 2.

[0063]

[Table 2] Bottle material Volume (l) Coating agent 1 month after initial oxygen Permeability 25 ° C Humidity 65% (ml / pkg ・ day) Experimental example 6 PET 0.3 PVA 0.02 0.02 Comparative example 6 PET 0.3 PVA 0.02 0.04 Experimental example 7 PET 0.3 EVOH 0.01 Comparative Example 7 PET 0.3 0.05 Experimental Example 8 PP 0.3 PVDC 0.25 Comparative Example 8 PP 0.3 0.88 In the stretch blow bottle of this Example, a resin film was formed and stretched, so that oriented crystallized. Since the molecular gap of the resin becomes narrower and the size of the gas molecule is approximately the same, the gas barrier properties such as oxygen barrier property, carbon dioxide barrier property and odor barrier property are improved. Particularly, according to the blow bottle formed by stretch-blowing the preform, when the preform is stretch-blow-molded, the resin film is also stretched to narrow the inter-lattice gap and improve the gas barrier property. When the alkoxide or the alkoxide hydrolyzate is contained in the crystal, the gas barrier property is further improved due to the good gas barrier property of the metal. Further, according to the method of manufacturing the preform 1 and the blow bottle of the present embodiment, the preform 1 coated with the resin film having the gas barrier property in advance is stretch-blown. By comparison, it is possible to obtain a container having a sufficient gas barrier property in spite of a short manufacturing time and a low manufacturing cost.

[0064]

According to the container and the container manufacturing method of the present invention, since the resin coating is formed, the gas having oxygen barrier property, carbon dioxide barrier property, odor barrier property, etc. can be obtained. The barrier property is improved. Particularly, according to the container formed by stretch blow molding of the preform,
When the preform is stretch blow-molded, the resin film is also stretched and oriented crystals are formed, and the interstitial spaces are narrowed to improve the gas barrier property. When the alkoxide or the alkoxide hydrolyzate is contained in the crystal, the gas barrier property is further improved.

According to the preform of claim 6 of the present invention and the manufacturing method of claims 7 to 8, the container is formed by stretch blow molding of the preform. Although the manufacturing time is shorter and the manufacturing cost is lower than that of, it is possible to obtain a container having a sufficient gas barrier property.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an uncoated preform according to an embodiment of the present invention.

FIG. 2 is an explanatory view of a state in which activation processing of the preform surface of FIG. 1 is performed.

FIG. 3 is an explanatory diagram showing a state of immersion of a preform in a coating agent after activation treatment.

FIG. 4 is a cross-sectional view of a state in which a preform after forming a resin film with a coating agent is stretch-blown.

FIG. 5 is a cross-sectional view of the coated preform of this example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Preform 2 Screw part 3 Flange part 4 Body part 5 Coating agent 6 Liquid tank 7 Plastic bottle 8 Resin coating 8'Stretched resin coating 9 Mold 10 Mold 11 Stretching rod

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location B65D 23/02 B65D 23/02 Z // B29L 9:00 22:00

Claims (7)

[Claims] 1. A resin coating comprising a polyvinyl alcohol-based coating agent, a vinylidene chloride-based coating agent, or an ethylene vinyl alcohol copolymer-based coating agent as a single substance or a complex thereof on the surface. container. 2. The container according to claim 1, wherein the resin coating contains an alkoxide or an alkoxide hydrolyzate in a range of 1% by weight to 70% by weight. 3. The container according to claim 2, wherein the alkoxide metal is either silicon or aluminum. 4. A polyvinyl alcohol-based coating agent, which is obtained by subjecting the surface of a container to an activation treatment for enhancing chemisorption.
Resin coating consisting of vinylidene chloride-based coating agent or ethylene vinyl alcohol copolymer-based coating agent alone or a composite thereof, or alkoxide or alkoxide hydrolyzate from 1 wt% to 70 wt% concentration A method for producing a container, which comprises forming a resin film contained within the range. 5. A preform for molding the container according to any one of claims 1 to 3, wherein a resin coating film having a gas barrier property is formed on the surface of the preform. 6. A container having a gas barrier resin coating film formed on the surface by stretch-blow molding the preform of claim 5. 7. A preform surface is subjected to an activation treatment for enhancing chemisorption, and then a resin coating having gas barrier properties or an alkoxide or alkoxide hydrolyzate is added from a concentration of 1% by weight to a concentration of 70% by weight. The method for producing a container is characterized in that one of the resin coatings contained within the range is formed, and then the preform is heated and stretch blown.