JPH0347655B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention provides a bottle made of saturated polyester whose body is biaxially stretched, which has a high degree of gas barrier property, particularly excellent barrier property against oxygen gas, and a high degree of surface hardness. This invention relates to a method for treating bottles made of saturated polyester. [Prior Art] Saturated polyester bottles with biaxially stretched bottle bodies are non-toxic and have superior moisture and gas barrier properties compared to molded products made of other synthetic resins. Because of this, it is widely used as containers for cosmetics, medical containers, etc., but its gas barrier properties are not sufficient to stably store foods and medical products that are easily deteriorated by the presence of air for long periods of time. Moreover, because of its low surface hardness, it has the disadvantage that the container surface is easily scratched even if the walls of the container come into contact with each other during transport or filling operations. There is. [Problems to be Solved by the Present Invention] In order to improve the above-mentioned conventional drawbacks, the present invention provides a process for easily obtaining a saturated polyester bottle that has excellent gas barrier properties, particularly barrier properties against oxygen gas, and has high surface hardness. The purpose is to provide a method. [Means for Solving the Problems] A first invention provides a bottle made of saturated polyester having a biaxially stretched bottle body, and a fine powder having oxygen adsorption performance on at least the outer surface of the wall of the bottle body. A primer layer is formed by applying a thermoplastic resin or a thermosetting resin containing After forming the first coating resin layer, the surface of the first coating resin layer is subjected to ultraviolet irradiation treatment, and then a photosensitizer is applied to a synthetic resin different from the resin forming the first coating resin layer. This is a method for treating a bottle made of saturated polyester, in which a second coating resin layer is formed by applying a synthetic resin containing saturated polyester, and the surface of the second coating resin layer is then subjected to ultraviolet irradiation treatment. Further, the second invention provides a bottle made of saturated polyester having a biaxially stretched bottle body, and a thermoplastic resin containing inorganic fine powder having oxygen adsorption performance on at least the outer surface of the wall of the bottle body. Alternatively, a thermosetting resin is applied to form a primer layer, and then a hard resin containing a photosensitizer and transparent or translucent inorganic fine powder containing silicon dioxide as a main component is applied to the surface of the primer layer. After forming a first coating resin layer by applying a synthetic resin having film-forming ability, the surface of the first coating resin layer is subjected to ultraviolet irradiation treatment, and then the surface of the first coating resin layer is coated with the first coating resin layer. A synthetic resin that has a hard film-forming ability different from the resin forming the coating resin layer, and a synthetic resin that contains a photosensitizer and transparent or translucent inorganic fine powder containing silicon dioxide as a main component. This is a method for treating a saturated polyester bottle that has a frosted glass appearance by forming the second coating resin layer and then irradiating the surface of the second coating resin layer with ultraviolet rays. Additionally, thermoplastic resins used for the primer layer include ethylene-vinyl acetate copolymer, vinyl chloride polymer, vinyl acetate polymer, vinyl chloride-vinyl acetate copolymer, isocyanate polymer, chlorinated polyethylene, Thermoplastic synthetic resins selected from chlorinated polypropylene, soluble nylon, urea polymers, melamine polymers, phenolic polymers, epoxy polymers, modified polymers thereof, or copolymers thereof A thermosetting synthetic resin selected from among these is used. In addition, the inorganic fine powder having oxygen adsorption performance (hereinafter referred to as an oxygen scavenger) is, for example, fine powder of activated carbon, activated iron oxide, palladium, hydrosulfite, iron carbide, reduced iron, etc. A primer layer is formed by uniformly dispersing it in a synthetic resin and applying it to the surface of the bottle wall. In addition, the synthetic resin having a hard film forming ability used for the first or second coating resin layer includes unsaturated polyester resin, acrylic resin, alkyd resin, epoxy resin, urethane resin, acetal resin, or Of these modified resins or copolymer resins, the synthetic resin used for the first coating resin layer and the synthetic resin used for the second coating resin layer are:
Use different types. Furthermore, as the photosensitizer used in the present invention, known ones such as benzoin, benzyl, benzoin alkyl ether, benzophenone, Michler's ketones, and chlorothioxanthone are used. [Operation] The first invention consists of the above configuration,
A primer layer is formed by adding about 3 to 10% by weight of an oxygen scavenger to the thermoplastic resin or thermosetting resin, and applying the uniformly dispersed product to a thickness of about 0.1 to 5 μm. If the amount of the oxygen scavenger is less than 3% by weight, the gas barrier properties will not be sufficient, and if it exceeds 10% by weight, the primer layer cannot be uniformly formed. The primer layer is an intermediate layer necessary for forming the first coating resin layer, which will be described later, firmly and integrally with the outer surface of the bottle body made of saturated polyester, and also contains an oxygen scavenger. This improves the gas barrier properties of saturated polyester bottles. Furthermore, compared to a case where the coating resin layer contains an oxygen scavenger, the first and second coating resin layers described below can be made more uniform and have higher hardness. Next, a coating agent made of a synthetic resin containing a photosensitizer and capable of forming a hard film is applied to the surface of the primer layer to a thickness of about 10 to 45μ, and then subjected to ultraviolet irradiation treatment. A first coating resin layer is formed. By the ultraviolet irradiation treatment,
The first coating resin layer forms a high degree of cross-linking in a short time, and can be formed into a high degree of coating layer. The thickness is
If it is less than 10μ, both gas barrier properties and surface hardness are insufficient, and if it exceeds 45μ, a second coating resin layer to be described later will be formed thereon.
It's too thick than necessary. The ultraviolet irradiation treatment is performed using a high-pressure mercury lamp, metal halide lamp, or the like having a wavelength of about 200 to 450 nm. Next, a coating agent containing a photosensitizer and a synthetic resin having a film-forming ability different from that of the synthetic resin used for the first coating resin layer was applied to the surface of the first coating resin layer in the same manner as above. After applying it in thickness,
Similarly to the above, the surface is subjected to ultraviolet irradiation treatment to form a second coating resin layer. That is, the first invention contains an oxygen scavenger in the primer layer, coats the surface of the primer layer with the paint of the first coating resin layer and the second coating resin layer containing the photosensitizer, and Since the coating resin layer is formed by ultraviolet irradiation treatment, it is possible to form a strong and integral coating resin layer with a short curing treatment, so it is biaxially stretched which is relatively easy to deform due to heat. There is no risk of distortion due to deformation in the saturated polyester bottle. However, the synthetic resins used for the first coating resin layer and the second coating resin layer must be different types of synthetic resins, and although the details of the reason are not clear, it is necessary to use different types of synthetic resins for the first coating resin layer and the second coating resin layer. A bottle having two coated resin layers has excellent gas barrier properties, particularly oxygen gas barrier properties, and has a high strength bottle body. Moreover, bottles made of saturated polyester having a highly hard surface can be easily mass-produced. Further, the second invention is the first invention in the first invention.
3 to 10% by weight of transparent or translucent inorganic fine powder containing silicon dioxide as a main component is added to the coating resin layer and the second coating resin layer, respectively, and the treatment is carried out in the same manner as in the first invention. It is. On the other hand, transparent or translucent inorganic fine powder containing silicon dioxide as a main component includes, for example, bead-shaped glass and flake-shaped glass, but flake-shaped glass is preferred from the viewpoint of the gas barrier effect of the resulting bottle. It is preferable to use Further, the inorganic fine powder is added in an amount of 3 to 10% by weight. If it is less than 3% by weight, the frosted glass appearance is insufficient, and if it exceeds 10% by weight, it is difficult to form a uniform coating resin layer. That is, the second invention improves the strength of the bottle body like the first invention, does not reduce the excellent gas barrier properties and high surface hardness, and also has a saturated glass-like appearance. Polyester bottles can be easily mass-produced. [Example] Fig. 1 is a front view of a bottle made of saturated polyester, which is the subject of the present invention, Fig. 2 is a partially enlarged sectional view of the wall of the bottle body of the first invention, and Fig. 3 is a This is a partially enlarged cross-sectional view of the bottle body of the second invention. Next, the present invention will be specifically described with reference to these drawings. Bottle 1 made of saturated polyester, object of the present invention
It consists of a bottom part 2, a body part 3, and a mouth part 4, and the bottle 1 is a well-known biaxially stretched bottle. The bottle 1 is preferably pretreated to remove oil, dirt, etc. adhering to the outer surface of the wall 5 of the bottle 1 in a bath with a cleaning agent such as a fluorine-based solvent that has no adverse effects. Next, a coating agent in which 5% by weight of activated iron oxide as an oxygen scavenger is uniformly dispersed in epoxy resin is applied to the outer surface of the wall 5 of the body 3 of the bottle 1 to a thickness.
A primer layer 6 is formed by applying the primer to a thickness of 1μ and pre-drying if necessary. Next, on the surface of the primer layer 6, a mixture of epoxy resin as a synthetic resin capable of forming a hard film and benzoin alkyl ether added as a photosensitizer was applied to a thickness of 30 μm.
This is subjected to ultraviolet irradiation treatment to form the first coating resin layer 7. Furthermore, on the surface of the first coating resin layer 7,
Similarly, an alkyd resin was used as a synthetic resin having the ability to form a hard film, and a photosensitizer was added to this resin, which was coated to a thickness of 30μ, and then subjected to ultraviolet irradiation treatment to form the second coating resin layer 8. Form. FIG. 3 shows an embodiment of the second invention, in which a primer layer 16 is formed on the outer surface of the bottle body wall 15 in exactly the same manner as in the first invention, and then the primer layer 16 is A synthetic resin having a hard film-forming ability added with 4% by weight of a photosensitizer and a fine powder of silicon dioxide is applied to the surface of No. 16, and then subjected to ultraviolet irradiation treatment to form a first coating resin layer. 17, and then coated with a synthetic resin capable of forming a hard film on its surface, as in the first invention, with 5% by weight of a photosensitizer and the above-mentioned silicon dioxide fine powder added thereto. A second coating resin layer 18 is formed by performing ultraviolet irradiation treatment. The table below shows experimental results regarding gas barrier properties, particularly barrier properties against oxygen gas. That is, a saturated polyester bottle that has not been subjected to the treatment of the present invention is used as a blank, and an epoxy resin is used.
The same amount of oxygen scavenger as in the above example was added to this as a primer layer, and the surface of this was coated with a single layer of UV-cured urethane resin to which a photosensitizer was added, and the urethane resin The figure shows the amount of oxygen permeation in the case of a single coated resin layer cured by ultraviolet light using an alkyd resin instead of the above-mentioned example of the present invention. The total thickness of one layer of the urethane resin, one layer of alkyd resin, and two layers of the urethane resin and alkyd resin of the present invention is all the same as 60 μm.

[Table] As is clear from the above table, the bottle treated by the method of the present invention has an oxygen permeation rate of about 20% compared to the blank.
% reduction, and can also be reduced by about 15% for bottles coated with one layer of urethane resin and one layer of alkyd resin. That is, even if the total thickness of the first coating resin layer and the second coating resin layer obtained by the method of the present invention is the same as that of one layer of conventional ultraviolet curable resin, it is equivalent to that of one layer of conventional ultraviolet curable resin. In comparison, the amount of oxygen permeation can be reduced. Further, if the amount of oxygen permeation is made the same, the thickness of the two coating resin layers of the present invention can be made slightly thinner than the thickness of one conventional ultraviolet curable resin layer. [Effects of the Invention] As described above, the first invention forms a primer layer containing an oxygen scavenger on the outer surface of a bottle made of saturated polyester resin, and furthermore, the thickness of the conventional ultraviolet hard resin film is Two coating resin layers are formed with the same thickness, and each of the two coating resin layers is treated with ultraviolet rays to form a hard film, so it is possible to coat a bottle made of saturated polyester, which is relatively easily deformed by heat. Since a strong and integral hard coating can be formed in a short curing treatment without causing distortion due to thermal deformation, the outer surface of the bottle can be made highly hard. In addition, an oxygen scavenger is added to the primer layer, and different types of synthetic resins are used in the two coating resin layers, improving gas barrier properties, especially against oxygen gas. In addition, since no oxygen scavenger is added to the hard resin layer as in conventional methods, the hard coating resin layer is made more uniform, the strength of the bottle body is high, and the hard coating resin layer is made of high hardness. It can be done. Furthermore, the second invention provides a bottle made of saturated polyester having gas barrier properties and a high hardness surface as described in the first invention, and also makes it possible to easily form a bottle with a frosted glass-like appearance. can. Furthermore, if a colored oxygen scavenger is used as the oxygen scavenger added to the primer layer, it can be used to create a saturated bottle with various properties according to requirements, such as a colored transparent bottle with ultraviolet blocking performance, or a colored frosted glass-like bottle. Polyester bottles are easily available.

[Brief explanation of drawings]

FIG. 1 is a front view of a bottle made of saturated polyester, which is the object of the present invention, FIG. 2 is an enlarged sectional view of the wall of the bottle body according to the first invention, and FIG. 3 is a front view of the bottle body according to the second invention. It is an enlarged sectional view of a wall part. 1: Bottle made of saturated polyester, 3: Biaxially stretched bottle body, 5, 15: Wall of bottle body, 6,
16: Primer layer, 7, 17: First coating resin layer, 8, 18: Second coating resin layer.

Claims (1)

[Scope of Claims] 1. A bottle made of saturated polyester having a biaxially stretched bottle body, at least on the outer surface of the wall of the bottle body, containing a thermoplastic resin or a fine powder having oxygen adsorption performance. A thermosetting resin was applied to form a primer layer, and then a synthetic resin containing a photosensitizer and capable of forming a hard film was applied to the surface of the primer layer to form a first coating resin layer. After that, the surface of the first coating resin layer is subjected to ultraviolet irradiation treatment, and then a photosensitizer is added to a synthetic resin having a hard film-forming ability different from that of the resin forming the first coating resin layer. A bottle made of saturated polyester, characterized in that the second coating resin layer is coated on the surface of the first coating resin layer, and then the second coating resin layer surface is subjected to ultraviolet irradiation treatment. Processing method. 2. A thermoplastic resin or thermosetting resin containing fine powder having oxygen adsorption ability is applied to at least the outer surface of the wall of the bottle body of a saturated polyester bottle having a biaxially stretched bottle body. to form a primer layer, and then, on the surface of the primer layer, a synthetic resin having the ability to form a hard film containing a photosensitizer and transparent or translucent inorganic fine powder containing silicon dioxide as a main component is applied. After coating to form a first coating resin layer, the surface of the first coating resin layer is subjected to ultraviolet irradiation treatment, and then the first coating resin layer is formed on the surface of the first coating resin layer. A synthetic resin that has the ability to form a hard film, which is different from resin, is coated with a photosensitizer and a transparent or translucent inorganic fine powder whose main component is silicon dioxide.
1. A method for treating a bottle made of saturated polyester, the method comprising: forming a coating resin layer, and then subjecting the surface of the second coating resin layer to ultraviolet irradiation treatment.