JPS647572B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a bottle made of saturated polyester that has excellent surface hardness and gas barrier properties, particularly oxygen gas barrier properties. The object of the present invention is to provide a method for easily manufacturing a bottle made of saturated polyester that has the following properties.

Bottles made of saturated polyester with a biaxially stretched bottle body are non-toxic and have superior moisture and gas barrier properties compared to molded products made of other synthetic resins. It is widely used as a glass-like container in containers for food products such as liquid seasonings, containers for pharmaceutical products, etc., but it is used to store the contents of food products, medicines, etc. in a stable state for a long period of time. In addition, the gas barrier properties, especially the oxygen gas barrier properties, are not sufficient, and the hardness of the surface is very low, so containers rub against each other during transport or filling operations. It also has drawbacks such as easy scratches on the outer surface of the container wall, which lowers the commercial value.

In contrast, the methods of the present invention provide a method for easily and reliably obtaining a saturated polyester bottle having excellent properties in terms of surface hardness and gas barrier properties.

That is, the first claimed invention is:
The second invention provides a method for obtaining a bottle that has excellent properties in terms of transparency as well as excellent surface hardness and gas barrier properties. The third aspect of the invention provides a method for obtaining a bottle that has a frosted glass-like appearance and also has excellent surface hardness and gas barrier properties. Furthermore, the fourth aspect of the invention provides a method for obtaining a bottle that has a frosted glass appearance, excellent surface hardness, and higher gas barrier properties.

The structure of the method for manufacturing a saturated polyester bottle of the present invention will be explained below based on the drawings.

Fig. 1 is a partially cross-sectional front view of a parison that is subjected to blow molding in a mold for forming a bottle body in the method for manufacturing a saturated polyester bottle of the present invention, and Fig. 2 is a front view showing a parison that is blow-molded in a mold for forming a bottle body. FIG. 3 is an enlarged sectional view showing an example of the wall of the bottle body of the bottle obtained according to the first invention; FIG. FIG. 4 is an enlarged sectional view showing an example of the wall of the bottle body of a bottle obtained according to the second invention, and FIG. FIG. 6 is an enlarged sectional view showing an example of the wall of the bottle body of the obtained bottle;
The figure is an enlarged sectional view showing an example of the wall of the bottle body of the bottle obtained according to the fourth aspect of the invention.

In the method for manufacturing a bottle made of saturated polyester, which is the first aspect of the invention, as a first step, a parison 1 with a bottom and an open top is formed from saturated polyester.

As a second step, at least the outer surface of the body wall of the parison 1 is coated with a urea polymer, a melamine polymer, a phenol polymer, an epoxy polymer, a modified polymer of each, or a copolymer of these. Thermosetting synthetic resin selected from the group consisting of ethylene-vinyl acetate copolymer, vinyl chloride polymer, vinyl acetate polymer, vinyl chloride-vinyl acetate copolymer, soluble nylon, chlorinated polyethylene, chlorinated A paint containing a thermoplastic synthetic resin selected from polypropylene is applied and, if necessary, pre-dried to form a primer layer 2 consisting of a film with a thickness of about 3 to 50 microns.

Furthermore, as a third step, a known photosensitizer such as benzoin, benzyl, benzoin alkyl ether, benzophenone, etc. is added to the surface of the primer layer 2 to a synthetic resin that has both the ability to form a hard surface and the ability to form a transparent film. A coating resin layer 3 having a thickness of about 10 to 100 μm is formed by applying a coating material made of the same coating components.

As a fourth step, the surface of the coating resin layer 3 is subjected to ultraviolet irradiation treatment to such an extent that the coating resin layer 3 is in a semi-cured state, thereby obtaining a parison 4 in which the coating resin layer 3 is in a semi-cured state.

Next, as a fifth step, the above-mentioned parison 4 is set in a mold 5 for molding the bottle body, and the parison 4 is biaxially stretched or blow-molded under heating that allows expansion, so that the parison 4 is expanded by 5 to 6 times. A saturated polyester bottle 6 is obtained by expanding the bottle to a certain degree and forming the bottle.

Subsequently, in the sixth and final step, the outer wall surface of the saturated polyester bottle 6,
That is, the surface of the coating resin layer 3' is subjected to ultraviolet irradiation treatment,
A high degree of crosslinking is introduced into the coating resin layer 3'.

In the first aspect of the invention comprising the above steps, the bottle body wall has a structure as shown in FIG. A saturated polyester bottle with a multilayer structure is formed, in which a highly cross-linked transparent coating resin layer 3' is formed firmly and integrally on the wall part 1' of the bottle via a primer layer 2'. It's something you get.

In the second aspect of the invention, in the second step of the process of the first aspect of the invention, a urea polymer, a melamine polymer, a phenolic polymer, an epoxy polymer, etc. Thermosetting synthetic resins selected from polymers, respective modified polymers, copolymers of these, or ethylene-vinyl acetate copolymers, vinyl chloride polymers, vinyl acetate polymers, vinyl chloride-vinyl acetate Fine powder having oxygen adsorption ability in a thermoplastic synthetic resin selected from copolymers, soluble nylon, chlorinated polyethylene, and chlorinated polypropylene;
For example, a coating agent in which fine powders of activated carbon, activated iron oxide, palladium, hydrosulfite, iron carbide, reduced iron, etc. are uniformly dispersed is applied, pre-dried as necessary, and a coating with a thickness of about 3 to 50 μm is applied. This process involves forming a primer layer consisting of a film.

Furthermore, in the third aspect of the invention, in the third step of the process of the first aspect of the invention, a synthetic material having both the ability to form a hard surface and the ability to form a transparent film is produced. In the resin,
A small amount of a known photosensitizer such as benzoin, benzyl, benzoin alkyl ether, benzophenone, etc., and a transparent or translucent inorganic fine powder mainly composed of silicon dioxide, such as bead-shaped glass,
A coating agent to which glass flakes and the like are added is applied to the surface of the primer layer formed in the second step to form a coating resin layer with a thickness of about 10 to 100 μm.

Furthermore, in the fourth aspect of the invention, in the second step of the process of the first aspect of the invention, a urea polymer, a melamine polymer, and a phenolic polymer are ,
Thermosetting synthetic resins selected from epoxy polymers, respective modified polymers, copolymers of these, ethylene-vinyl acetate copolymers, vinyl chloride polymers, vinyl acetate polymers, vinyl chloride- vinyl acetate copolymer, soluble nylon,
Fine powder having oxygen adsorption ability, such as activated carbon, activated iron oxide, palladium, hydrosulfite, iron carbide, reduced iron, etc., is added to a thermoplastic synthetic resin selected from chlorinated polyethylene and chlorinated polypropylene. The process involves applying a uniformly dispersed coating agent, pre-drying it if necessary, and forming a primer layer consisting of a film with a thickness of approximately 3 to 50 μm.In the third step, the hard surface forming ability is A small amount of known photosensitizers such as benzoin, benzyl, benzoin alkyl ether, benzophenone, etc., and a fine amount of transparent or translucent inorganic material containing silicon dioxide as the main component are mixed into a synthetic resin that has the ability to form a transparent film. A step of applying a coating agent to which powder, e.g., bead-like glass, flake-like glass, etc. is added, to the surface of the primer layer formed in the second step to form a coating resin layer with a thickness of about 10 to 100 μm. It is something to be taken.

Therefore, in the second aspect of the invention, the bottle body wall is configured as shown in FIG. 4, that is, the outer surface of the wall 11 of the saturated polyester bottle is subjected to biaxial stretching. From a cured film in which a high degree of crosslinking is introduced through a primer layer 12 made of a synthetic resin in which fine powder with oxygen adsorption ability is added and blended into a thermosetting synthetic resin or thermoplastic synthetic resin. A saturated polyester bottle having a multilayer structure in which the coating resin layer 13 is strongly and integrally formed is obtained.

Furthermore, in the third aspect of the invention, the bottle body wall has a configuration as shown in FIG.
That is, transparent or translucent silicon dioxide is applied to the outer surface of the wall portion 21 of the biaxially stretched saturated polyester bottle via the primer layer 22 made of the thermosetting synthetic resin or thermoplastic synthetic resin. Obtain a saturated polyester bottle with a multilayer structure in which a coating resin layer 23 made of a cured film in which a fine powder of inorganic material as a main component is uniformly dispersed and a highly cross-linked bond is introduced is strongly and integrally formed. It is something.

Furthermore, in the fourth aspect of the invention, the bottle body wall has a structure as shown in FIG.
That is, on the outer surface of the wall portion 31 of the saturated polyester bottle that has been subjected to biaxial stretching, fine powder having oxygen adsorption ability is added and blended into the thermosetting synthetic resin or thermoplastic synthetic resin. A coating resin layer consisting of a cured film in which transparent or translucent inorganic material fine powder mainly composed of silicon dioxide is uniformly dispersed through a primer layer 32 made of a synthetic resin, and a high degree of crosslinking is introduced. 3
3 is to obtain a strong, integrally formed multi-layered saturated polyester bottle.

The method for manufacturing a saturated polyester bottle of the present invention is carried out by the steps described above,
The primer layer formed in the second step of each invention is an intermediate layer necessary for forming a coating resin layer having a hard surface firmly and integrally on the outer surface of the body wall of the parison made of saturated polyester. If this primer layer is omitted, it is impossible to form the coating resin layer firmly and integrally on the outer surface of the body wall of the parison.

In addition, the synthetic resins having a hard surface forming ability or the synthetic resins having both a hard surface forming ability and a transparent film forming ability used in the third step of each invention include unsaturated polyester, acrylic resin,
Examples include alkyd resins, epoxy resins, urethane resins, acetal resins, modified resins of these resins, and copolymer resins of these resins. The coating agent used to form the coating resin layer in this third step is contained in a small amount in the aforementioned synthetic resin that has the ability to form a hard surface, or a synthetic resin that has both the ability to form a hard surface and the ability to form a transparent film. A known photosensitizer such as benzoin, benzyl, benzoin alkyl ether, benzophenone, Michler ketones, chlorothioxanthone, 2-isopropylthioxanthone is added, and if necessary, Of course, a small amount of a photopolymerization accelerator such as an amine compound, a chain transfer agent such as a mercaptan, etc. can be added.

The ultraviolet irradiation treatment in the fourth and final steps of each invention is performed using a high-pressure mercury lamp, metal halide lamp, or the like having a wavelength of about 200 to 450 nm.

In the second step of the second and fourth claims, a primer layer is formed of a synthetic resin in which fine powder having oxygen adsorption ability is uniformly added and dispersed. It is usually formed by using a coating agent whose solid component is a composition in which fine powder having an oxygen adsorption capacity of about 3 to 10% by weight is added to a synthetic resin. In this case, the addition of fine powder having oxygen adsorption ability further improves the gas barrier properties of the resulting saturated polyester bottle, but
This is because if the addition of fine powder with oxygen adsorption ability is less than 3% by weight of the solid component, the effect will not be sufficient, and if it exceeds 10% by weight, it will be difficult to form a uniform coating layer with the coating agent. . Furthermore, by selecting a fine powder having a coloring oxygen adsorption ability in forming the primer layer, it is possible to produce a bottle made of saturated polyester that also has ultraviolet blocking performance.

Further, in the third and fourth claims, the transparent or translucent inorganic material fine powder containing silicon dioxide as a main component used for forming the coating resin layer in the third step is obtained. In addition to further improving the gas barrier properties of the saturated polyester bottle, it also gives the saturated polyester bottle a frosted glass-like appearance.Approximately 3 to 10% by weight of inorganic material fine powder is added to the synthetic resin. The coating resin layer is formed by using a coating agent whose solid component is a composition to which is added. This is because if the addition of transparent or translucent inorganic fine powder containing silicon dioxide as the main component is less than 3% by weight of the solid component, the effect of adding the fine powder will not be sufficient, and if the addition is less than 10% by weight, This is because, if it exceeds the range, it becomes difficult to form a uniform coating layer with the coating agent. In addition, examples of the transparent or translucent inorganic material fine powder containing silicon dioxide as a main component include bead-shaped glass and flake-shaped glass, but from the viewpoint of the gas barrier effect imparted to the resulting bottle, It is preferable to use glass flakes.

The method for producing a bottle made of saturated polyester of the present invention is constructed as described above, and the outer surface of the wall of the bottle body can be rubbed with stainless wool or has a hardness of about 3H to 4H. A saturated polyester bottle coated with a coating resin layer that provides a hard surface that does not leave any scratches even when rubbed with a sharp pencil lead and an excellent gas barrier property, especially an oxygen gas barrier. Moreover, it has the effect of being able to be mass-produced reliably.

In particular, according to the first aspect of the invention, gas barrier properties are improved compared to conventional single-layer saturated polyester bottles whose bodies are biaxially stretched.
It is possible to produce a bottle that has improved transparency by about 10 to 20% and has the same excellent transparency as the conventional single-layer saturated polyester bottle whose body is biaxially stretched.

According to the second aspect of the invention, it is possible to produce a bottle that has further improved gas barrier properties than the bottle obtained according to the first aspect of the invention.

Furthermore, according to the third aspect of the invention, the gas barrier property is improved by about 15 to 25% compared to a conventional single-layer saturated polyester bottle whose body is biaxially stretched. It is possible to produce a bottle that has a frosted glass appearance.

Furthermore, according to the fourth aspect of the invention, the bottle has a higher gas barrier property than the bottle obtained according to the third aspect of the invention, and has a frosted glass appearance. It is possible to manufacture bottles exhibiting

[Brief explanation of drawings]

Fig. 1 is a partially cross-sectional front view of a parison that is subjected to blow molding in a mold for forming a bottle body in the method for manufacturing a saturated polyester bottle of the present invention, and Fig. 2 is a front view showing a parison that is blow-molded in a mold for forming a bottle body. FIG. 3 is an enlarged sectional view showing an example of the wall of the bottle body of the bottle obtained according to the first invention; FIG. FIG. 4 is an enlarged sectional view showing an example of the wall of the bottle body of a bottle obtained according to the second invention, and FIG. FIG. 6 is an enlarged sectional view showing an example of the wall of the bottle body of the obtained bottle;
The figure is an enlarged sectional view showing an example of the wall of the bottle body of the bottle obtained according to the fourth aspect of the invention. 1... Parison, 2... Primer layer, 3...
Coating resin layer, 4... Parison on which coating resin layer 3 is formed via primer layer 2, 5... Mold for molding a bottle body, 6... Bottle made of saturated polyester.

Claims (1)

[Claims] 1. A parison is formed using saturated polyester, and at least the outer surface of the body wall of the parison is coated with a urea polymer, a melamine polymer, a phenol polymer, an epoxy polymer, A thermosetting synthetic resin selected from each modified polymer, a copolymer thereof, or ethylene-
Vinyl acetate copolymer, vinyl chloride polymer, vinyl acetate polymer, vinyl chloride-vinyl acetate copolymer,
A primer layer is formed using a thermoplastic synthetic resin selected from soluble nylon, chlorinated polyethylene, and chlorinated polypropylene, and then a photosensitizer such as benzoin, benzyl, benzoin methyl ether, etc. is added to the surface of the primer layer. forming a coating resin layer made of a synthetic resin that has both the ability to form a hard surface and the ability to form a transparent film; Thereafter, the obtained parison is blow-molded in a bottle molding mold, and the surface of the coating resin layer is subsequently subjected to ultraviolet irradiation treatment. 2. A parison is formed using saturated polyester, and at least the outer surface of the body wall of the parison is coated with a urea polymer, a melamine polymer, a phenolic polymer, an epoxy polymer, or each modified polymer, Thermosetting synthetic resin selected from copolymers of these or ethylene-
Vinyl acetate copolymer, vinyl chloride polymer, vinyl acetate polymer, vinyl chloride-vinyl acetate copolymer,
A primer layer is formed using a thermoplastic synthetic resin selected from soluble nylon, chlorinated polyethylene, and chlorinated polypropylene to which fine powder having oxygen adsorption ability is added, and then a primer layer is formed on the surface of the primer layer. A coating resin layer is formed of a synthetic resin having a hard surface forming ability to which a photosensitizer such as benzoin, benzyl, or benzoin methyl ether is added, and the coating resin layer is further placed in a semi-cured state on the surface of the coating resin layer. A saturated polyester material made of saturated polyester, characterized in that the obtained parison is subjected to ultraviolet irradiation treatment to a certain extent, and then the obtained parison is blow-molded in a mold for molding a bottle, and the surface of the coating resin layer is subsequently subjected to ultraviolet irradiation treatment. How to make bottles. 3. A parison is formed using saturated polyester, and at least the outer surface of the body wall of the parison is coated with a urea polymer, a melamine polymer, a phenol polymer, an epoxy polymer, or each modified polymer. Thermosetting synthetic resin selected from copolymers of these or ethylene-
Vinyl acetate copolymer, vinyl chloride polymer, vinyl acetate polymer, vinyl chloride-vinyl acetate copolymer,
A primer layer made of a thermoplastic synthetic resin selected from soluble nylon, chlorinated polyethylene, and chlorinated polypropylene is formed, and then a photosensitizer such as benzoin, benzyl, benzoin methyl ether, etc. is added to the surface of the primer layer, A coating resin layer is formed using a synthetic resin having both a hard surface forming ability and a transparent film forming ability, to which a transparent or translucent inorganic material fine powder containing silicon dioxide as a main component is added, and furthermore, a coating resin layer is formed on the surface of this coating resin layer. Then, the coating resin layer is subjected to an ultraviolet irradiation treatment to the extent that it becomes a semi-cured state, and then the obtained parison is blow-molded in a mold for molding a bottle body, and the surface of the coating resin layer is subsequently subjected to an ultraviolet irradiation treatment. A method for producing a bottle made of saturated polyester, characterized by performing the following steps. 4 A parison is formed using saturated polyester, and at least the outer surface of the body wall of the parison is coated with a urea polymer, a melamine polymer, a phenol polymer, an epoxy polymer, or each modified polymer, Thermosetting synthetic resin selected from copolymers of these or ethylene-
Vinyl acetate copolymer, vinyl chloride polymer, vinyl acetate polymer, vinyl chloride-vinyl acetate copolymer,
A primer layer is formed using a thermoplastic synthetic resin selected from soluble nylon, chlorinated polyethylene, and chlorinated polypropylene to which fine powder having oxygen adsorption ability is added, and then a primer layer is formed on the surface of the primer layer. , a coating resin layer made of a synthetic resin capable of forming a hard surface to which is added a photosensitizer such as benzoin, benzyl, benzoin methyl ether, etc. and a transparent or translucent inorganic material fine powder containing silicon dioxide as a main component. form,
Further, the surface of this coating resin layer is subjected to ultraviolet irradiation treatment to such an extent that the coating resin layer is in a semi-cured state, and then the obtained parison is blow molded in a mold for molding a bottle body, and then the coating resin is A method for producing a saturated polyester bottle, characterized by subjecting the layer surface to ultraviolet irradiation treatment.