JP2002086492A - Method and apparatus for forming oxygen gas barrier layer on surface of molded article and molded article having oxygen gas barrier layer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and apparatus capable of easily and certainly forming an oxygen gas barrier layer even to the outer surface of a molded article having a complicated shape, and a molded article. SOLUTION: In an apparatus for forming an oxygen barrier layer on the surface of the molded article molded into a predetermined shape by supplying a resin into the mold space formed by closing freely openable and closable molds 11, 12, a freely advancing and retreating liquid film forming device 15, which advances to the position facing to the inner surfaces of the molds 11 and 12 when the molds 11 and 12 are opened and applies a precursor solution of an oxygen barrier film to the inner surfaces of the molds to form liquid films 17, and a heating device 16 for heating the inner surfaces of the molds after the retreat of the liquid film forming device 15 are provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method and an apparatus for forming an oxygen gas barrier layer on the surface of a molded article, and a molded article having an oxygen gas barrier layer.

[0002]

2. Description of the Related Art In some cases, a gas barrier layer is formed on at least one layer of a multilayer or single-layer molded product such as a container obtained by molding a resin.

[0003] Several methods are conventionally known for forming such an oxygen gas barrier layer. First, co-extrusion molding including an oxygen gas barrier layer such as a saponified ethylene-vinyl acetate copolymer (hereinafter sometimes abbreviated as EVOH) to impart oxygen gas barrier properties, and second, inorganic oxide There is a method of forming a film having a high oxygen gas barrier property on the surface of a molded article by vapor deposition or the like, and thirdly, a method of attaching an oxygen gas barrier film or a sheet-like label to the surface of the molded article by an in-mold label method or the like. .

[0004]

However, each of the above known methods has its own problems. First, in the first method, it is known that it is difficult to make the thickness of the oxygen gas barrier layer of a three-dimensional blow-molded multilayer molded article constant, and it is particularly difficult in a portion where the blow-up ratio is large and thin. Next, in the second method, since the film body is an inorganic oxide, the film strength due to repeated fatigue is weak, and pinholes are easily generated. In the third method, uniform evaporation can be obtained when the molded product has a flat surface, but if it has a three-dimensional shape, the film cannot follow this surface shape, making it difficult to attach, and joining Since a gap is formed in the region, the oxygen gas barrier property is reduced.

[0005] The present invention solves the above-mentioned problems in the known method, and provides a method for forming an oxygen gas barrier layer on the surface of a molded article, which can provide an oxygen gas barrier layer on a molded article having a complicated three-dimensional shape. It is another object of the present invention to provide a molded article having such an oxygen gas barrier layer.

[0006]

Means for Solving the Problems <Method of Forming Oxygen Gas Barrier Layer> In the present invention, in order to achieve the above object, an oxygen gas barrier layer is formed on the surface of a molded product obtained by molding a synthetic resin in a mold. In the method, the first step of applying a precursor solution of the oxygen gas barrier film to the inner surface of the mold to obtain a liquid film, and heating the inner surface of the mold to solidify the liquid film A second step of forming an oxygen gas barrier film, a third step of supplying a synthetic resin to the interior space of the mold to form a molded article, and transferring the oxygen gas barrier film to the molded article; And a fourth step of taking the product out of the mold. According to the present invention, the oxygen gas barrier film formed on the inner surface of the mold is transferred to a molded article molded by the mold, and becomes an oxygen gas barrier layer on the surface of the molded article.

In the present invention, prior to the first step of applying a precursor solution of the oxygen gas barrier film to obtain a liquid film, a preliminary step of forming a release agent layer on the inner surface of the mold in advance is provided. Is desirable. By doing so, the oxygen gas barrier film is easily peeled off from the inner surface of the mold at the time of transfer, thereby ensuring transfer.

In the present invention, in order to obtain a liquid film by applying a precursor solution of the oxygen gas barrier film, a spray method, a method for applying electric charge to coating liquid particles, a dipping treatment method, a brush coating method, a roller coating method, and the like. It is possible to apply any one of the coating methods, the heating of the inner surface of the mold to solidify the liquid film,
It can be performed by any one of a high-frequency induction heating method, a resistance heating method, and a circulating heating method using a heat medium oil.

<Oxygen Gas Barrier Layer Forming Apparatus>
As an apparatus for carrying out the above oxygen gas barrier layer forming method, an oxygen gas barrier layer is formed on a surface of a molded product which is formed into a predetermined shape by supplying a resin into a mold space formed by closing a mold that can be opened and closed. In the forming apparatus, a retractable liquid film for forming a liquid film by applying a precursor solution of an oxygen gas barrier film to the inner surface of the mold by advancing to a position facing the inner surface of the mold when the mold is opened It is characterized by having a forming device and a heating device for heating the inner surface of the mold after retreating the liquid film forming device.

According to the present invention, in such an apparatus, in order to form a layer of the release agent, it is preferable that the liquid film forming apparatus further includes means for applying the release agent to the inner surface of the mold in advance. .

The liquid film forming device is any one of a spray device, a device for applying a coating liquid particles, a dipping device, a brush coating device, and a roller coating device. The heating device is a high-frequency induction heating device, a resistance heating device. Or a circulating heating device using heat medium oil.

<Molded Article Having Oxygen Gas Barrier Layer> The molded article obtained by the present invention is a molded article having an oxygen gas barrier layer on the surface, wherein the oxygen gas barrier layer is formed on the inner surface of a mold. It is characterized in that the body is transferred onto the surface of the molded article by molding the molded article in a mold.

[0013]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows the molding of a molded article by the apparatus of the present embodiment in the order of steps.

The molding apparatus 10 includes a pair of dies 11, 12
And a predetermined space is formed on the mutually facing surfaces, and a resin is injected into this space to be molded.

In the present embodiment, the molds 11 and 12 are a male mold and a female mold that are compatible with each other for molding a cup-shaped container. At least one of the dies 11 and 12 is movable so that the opposing surfaces are relatively close to and away from each other. In the illustrated example, the male mold 11 is movable.
The mold 11 is provided with an injection hole 13 for resin injection.

Between the two dies 11 and 12 in the separated state,
A masking plate 14, a spray nozzle 15 as a means for applying a precursor solution of an oxygen gas barrier film, and an electrode 16A of a high-frequency power supply 16 are provided so as to protrude and retract at predetermined times. The masking plate 14 is configured such that one of the dies 12 is in contact with the contact surface 1 of the counterpart die 11.
The contact surface 12A is in contact with the contact surface 12A for a predetermined time. And during that interview time,
The spray nozzle 15 enters and sprays the precursor solution on the inner surface of the mold 12 so as to have a predetermined thickness, and then exits. Further, the electrode 1 of the high frequency power supply 16
6A has a shape for uniformly forming a predetermined gap with the inner surface of the mold 12;
4 and after the spray nozzle 15 exits, it enters and exits.

Next, the procedure for molding a molded article will be described. First, the two dies 11 and 12 are located apart from each other as shown in FIG. A masking plate 14 is arranged on one of the molds 12 on the contact surface 12A in a contact state. Thereafter, the spray nozzle 15 enters between the two dies 11 and 12, and spray-coats the precursor solution to a predetermined thickness on the inner surface of one of the dies 12 at a predetermined position. After application of the precursor solution by this spray, the spray nozzle 15
Is withdrawn from between the dies 11 and 12, and the masking plate 14 is also removed. The precursor solution is not applied to the contact surface 12A of the mold 12 by the masking plate 14. Next, between the two dies 11 and 12 in the separated state, FIG.
As shown in (B), the electrode 16A of the high frequency power supply 16 enters and takes a position where a predetermined gap is formed with the inner surface of the mold 12.
The inner surface of the mold 12 is induced at a high frequency by the electrode 16A, and receives the heat to receive the liquid film 1 of the precursor solution on the inner surface.
7 chemically reacts and the solvent evaporates to form an oxygen gas barrier film. Next, the electrode 16A is connected to both molds 1.
Leave outside 1,12. Thereafter, the mold 11 approaches the mold 12, and the contact surfaces 11A and 12A of the two contact each other to form a hermetically sealed molding space therebetween. Resin is injected. At this time, the resin is bonded to the gas barrier film by the heat of the resin. After the resin is solidified, the mold 11 is separated from the mold 12 as shown in FIGS. In this step, the oxygen gas barrier film is transferred to the surface of the molded article to form the oxygen gas barrier layer 18. Next, the molded article P having the oxygen gas barrier layer is taken out of the apparatus (FIG. 1).
(F)).

Thus, a molded article having an oxygen gas barrier layer is obtained. However, the present invention is not limited to the above-described embodiment, and can be variously modified. The precursor solution of the oxygen gas barrier film is disclosed in Japanese Patent No. 30070712,
237180 and JP-A-10-128923 can be used.

First, before applying the precursor solution of the oxygen gas barrier film to the inner surface of the mold, a release agent is applied to the inner surface as a preliminary step so that transfer can be performed easily and reliably. Can be.

Next, the application of the precursor solution is not limited to the spray method, but may be a method of applying a charge to the coating liquid particles, a dipping method,
Various methods such as a brush coating method and a roller coating method can be used. In addition, as a heating method for solidifying the applied liquid film, a resistance heating method, a circulating heating method using a heat medium oil, or the like can be used in addition to the high frequency induction heating method exemplified above.

EXAMPLES Example 1 4% by mass of polyacrylic acid (PAA) manufactured by Toa Gosei Chemical Co., 1% by mass of reduced starch saccharified product manufactured by Towa Kasei Kogyo Co., Ltd. Was mixed with 75% by mass of water and 20% by mass of isopropyl alcohol to prepare a 5% by mass mixed aqueous solution containing PAA and saccharified reduced starch in a mass ratio (solid content) of 80:20. To this mixed aqueous solution,
Further, 2% by mass of sodium hypophosphite based on the PAA solid content and sodium hydroxide in an amount capable of neutralizing 5% of the moles of all carboxyl groups of PAA are added to form a precursor of the oxygen gas barrier film. The body solution was prepared.

Next, the above precursor solution is applied to the inner surface of the mold which has been subjected to the surface treatment of the fluororesin by a spray method to form a liquid film, and the temperature of the inner surface of the mold is increased by a high frequency induction heating method. Heat treatment was performed at 250 ° C. to form an oxygen gas barrier layer having a thickness of about 5 μm on the inner surface of the mold.

The molding space formed by the inner surface of the mold is
Propylene-ethylene copolymer (simply P
P copolymer) and injection molding
A bottomed container was manufactured. Its shape has openings
Bottomed container (content 140cm ³) And oxygen gas burr
A layer is formed on the outer surface of the container. The PP copolymer
The physical properties of the body are 0.90 g / cm³(JIS: K-6
760), Vicat softening point 150 ° C (JI
S: measured by K-7206), melt flow rate 1
0 g / 10 min (measured at a temperature of 23 ° C.). Injection
In the molding process, the model J of the injection molding machine manufactured by Japan Steel Works, Ltd.
Using 75E, molding was performed at an injection pressure of 200 MPa.

The injection-molded container manufactured as described above was manufactured using OX-T manufactured by Modern Control.
Using RAN-100, oxygen permeability (30 ° C, 80% R
H) was measured (JIS: K7126). The oxygen permeability as a packaging container was 1 cm ³ / m ² · 24 h · atm.

<Embodiment 2> In order to facilitate the transfer of the oxygen gas barrier film even at a relatively low molding pressure such as blow molding, means for promoting peeling of the oxygen gas barrier film from the mold. A primer (release agent) was previously applied to a mold to form a primer layer having a thickness of about 1 μm on the inner surface of the mold. As a primer layer, the polyimide coating agent Semicofine SP-341 manufactured by Toray Industries, Inc. was diluted with n-methylpyrrolidone,
It was adjusted to mass%.

After the formation of the primer layer, the precursor solution of the oxygen gas barrier film is applied to the inner surface of the mold on which the primer layer is formed by a spray method, and the inner surface temperature of the mold is increased by a high frequency induction heating method. Heat treatment was performed while maintaining the temperature at 250 ° C. for 10 seconds to form an oxygen gas barrier layer having a thickness of about 5 μm on the inner surface of the mold.

A high-density polyethylene is used as a synthetic resin in a molding space formed on the inner surface of the mold. tea. Molded by K Co., Ltd. single-layer blow molding machine `` Koganemushi '', the primer layer and oxygen gas barrier film formed on the inner surface of the mold are integrated with this synthetic resin by transfer from the mold, A blow molded container having a primer layer and an oxygen gas barrier layer formed on the outer surface was obtained. The molding was performed at a molding pressure of 0.5 MPa.

The blow-molded container manufactured as described above was manufactured using OX-Ox manufactured by Modern Control.
Oxygen permeability using TRAN-100 (30 ° C, 80%
RH) was measured (JIS: K7126). The oxygen permeability as a packaging container was 1 cm ³ / m ² · 24 h · atm.

<Embodiment 3> In order to facilitate the transfer of the oxygen gas barrier film at a relatively low molding pressure, a means for promoting the peeling of the oxygen gas barrier film from the mold was previously determined by using a mold. A primer layer was applied to the mold to form a primer layer having a thickness of 1 μm on the inner surface of the mold. As the primer layer, a polyimide coating agent was used.

After the formation of the primer layer, the precursor solution of the oxygen gas barrier film is applied to the inner surface of the mold on which the primer layer is formed by a spray method, and the inner surface temperature of the mold is subjected to high frequency induction heating. Was maintained at 250 ° C. for 10 seconds to perform a heat treatment to form an oxygen gas barrier film having a thickness of about 5 μm on the inner surface of the mold.

A high-density polyethylene sheet (1.5 mm thick) is pressure-formed on the inner surface of the mold using a vacuum pressure forming machine manufactured by Senba System Co., Ltd., and the primer layer formed on the inner surface of the mold and the oxygen gas barrier property are formed. The membrane was integrated with the synthetic resin by transfer from a mold to obtain a compressed air molded container having a primer layer and an oxygen gas barrier layer formed on the outer surface. The molding was performed at a molding pressure of 0.5 MPa.

The pressure-formed container manufactured as described above was manufactured using OX-T manufactured by Modern Control.
Using RAN-100, oxygen permeability (30 ° C, 80% R
H) was measured (JIS K7126). The oxygen permeability as a packaging container was 1 cm ³ / m ² · 24 h · atm.

The heating time also depends on what the liquid film is like the above-mentioned heating temperature. Example-
For the precursor solution shown in 1, the preferred treatment time is 1 minute or less, more preferably 15 seconds or less, and most preferably 5 minutes or less.
Less than a second. The heat treatment time is preferably as short as possible from the viewpoint of productivity.

The preferred film thickness depends on the material of the formed oxygen gas barrier film.
When numerically expressing the case of the precursor solution shown in Example-1,
The thickness of the oxygen gas barrier layer is preferably 0.1 to 30 μm.
m, more preferably 0.2 to 5 μm, most preferably 0.5 to 3 μm.

[0035]

As described above, according to the present invention, an oxygen gas barrier film is formed on the inner surface of a mold prior to molding of a molded article with a resin, and the molded article is molded at the time of molding with the mold. Since the oxygen gas barrier layer was formed on the surface of the molded article by transferring the film to the surface, the number of manufacturing steps was reduced, and the method and apparatus were simple, but complicated. An oxygen gas barrier layer can be reliably provided even with a molded product having a suitable surface shape.

[Brief description of the drawings]

FIG. 1 is a diagram showing a molding procedure of a molded article by an apparatus according to an embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 11 mold 12 mold 15 liquid film forming device (spray nozzle) 16 heating device 17 liquid film 18 oxygen gas barrier layer P molded product (container)

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Masayuki Kashimura 18-13 Kamitamari, Tamari-mura, Niigata-gun, Ibaraki Pref. Resin Processing Center, Kureha Chemical Industry Co., Ltd. AD11 AG07 CA11 CB01 CB22 CK41 CM83 CN20 CN25 4F206 AA11E AD11 JA07 JB22 JF05 JQ81

Claims (7)

[Claims] 1. A method for forming an oxygen gas barrier layer on the surface of a molded product obtained by molding a synthetic resin in a mold, wherein a precursor solution of an oxygen gas barrier film is applied to the inner surface of the mold. A first step of obtaining a liquid film, a second step of heating the inner surface of the mold to solidify the liquid film to form an oxygen gas barrier film, and applying a synthetic resin to the internal space of the mold. A third step of transferring the oxygen gas barrier film to the molded article while supplying the molded article to the molded article, and a fourth step of taking the molded article out of the mold. A method for forming an oxygen gas barrier layer. 2. A preliminary step of forming a release agent layer on the inner surface of a mold before the first step of applying a precursor solution of an oxygen gas barrier film to obtain a liquid film. A method for forming an oxygen gas barrier layer on the surface of the molded article according to claim 1. 3. A method of applying a precursor solution of an oxygen gas barrier film body to obtain a liquid film by any one of a spraying method, a method of adhering charge of coating liquid particles, a dipping treatment method, a brush coating method, and a roller coating method. Applying one, and heating the inner surface of the mold to solidify the liquid film is performed by any one of a high-frequency induction heating method, a resistance heating method, and a circulation heating method using a heating medium oil. Item 2. A method for forming an oxygen gas barrier layer on a surface of a molded article according to Item 1. 4. An apparatus for supplying a resin into a mold space formed by closing a mold that can be opened and closed to form an oxygen gas barrier layer on a surface of a molded article molded into a predetermined shape. A retractable liquid film forming apparatus for applying a precursor solution of the oxygen gas barrier film to the inner surface of the mold to form a liquid film by advancing to a position facing the inner surface of the mold, and a liquid film forming apparatus. An apparatus for forming an oxygen gas barrier layer on a surface of a molded product, comprising a heating device for heating an inner surface of a mold after retreat. 5. The liquid film forming apparatus according to claim 4, further comprising means for applying a mold release agent to an inner surface of the mold in advance.
3. An apparatus for forming an oxygen gas barrier layer on the surface of a molded article according to 1.). 6. The liquid film forming device is any one of a spray device, a coating device for applying coating liquid particles, a dipping device, a brush coating device, and a roller coating device, and the heating device is a high frequency induction heating device, a resistance device. The apparatus for forming an oxygen gas barrier layer on the surface of a molded article according to claim 4, wherein the apparatus is any one of a heating apparatus and a circulation heating apparatus using heat medium oil. 7. A molded article having an oxygen gas barrier layer on its surface, wherein the oxygen gas barrier layer is formed by molding an oxygen gas barrier film formed on the inner surface of a mold in a mold of the molded article. A molded article having an oxygen gas barrier layer, which is transferred to the surface.