Yoshino Kogyosho Co., Ltd.

Fumio Negishi

Akiho Ota

Sadao Suzuki

Takuzo Takada

Harumi Kinoshita

Spherulites grow in such sections as neck, neck end, bottom center or bottom periphery of a hollow bottle-shaped container of biaxially oriented blow-molded polyethylene terephthalate where the resin is not substantially subjected to orientation, thereby to improve the thermal resistance, stiffness and content resistance of such sections to almost the same extent as the biaxially oriented sections of the container such as shoulder and cylindrical sections thereof. The aforesaid sections of the preformed piece before being blow-molded or of the blow-molded container where the resin is not substantially subjected to orientation are first heated at 120.degree.-180.degree. C. for 3-8 minutes and, then, annealed at room temperatures, with a result that such sections have a spherulite texture of an increased density and are opacified in white or milky white.

Polyester container

Spherulites are grown in such sections as neck, neck end, bottom center and/or bottom periphery of a hollow bottle-shaped container of biaxially oriented-blow molded polyethylene terephthalate (PET) resin where the resin is not substantially subjected to orientation, thereby to improve the thermal resistance, stiffness and content resistance of such sections to almost the same extent as the biaxially oriented sections of the container such as the shoulder and cylindrical sections thereof. The aforesaid non-oriented sections of the preformed piece before being blow-molded or of the blow-molded container are first heated at or above the glass transition temperature of the resin for about 2-8 minutes and are then annealed at room temperature, with the result that such sections have a spherulite texture of an increased density and are rendered opaque.

Method for producing polyester containers

A bottle-shaped container of saturated polyester having frosted or ground surface is manufactured by the steps of heating the outer layer portion of the injection-molded preformed piece to thereby crystallize the outer layer portion to opacify in white, and blow-molding the preformed piece in a blowing mold having at least part of its inner surface formed with rough surface sandblasted in advance to thereby form the rough surface on the bottle-shaped container on the crystallized outer layer portion surface. Thus, the bottle-shaped container incorporates pearl-like ground surface desired in a shape on the surface instead of the glossy surface peculiar to synthetic resin.

Method of manufacturing a bottle-shaped container of synthetic resin

The present invention relates to a bottle formed of a saturated polyester resin, and to a method of coating the bottle with a decorative paint coating adapted to adhere to the bottle without peeling. The decorative coating is prepared by coating the bottle in sequence with a primer layer, an undercoat layer, a decorative paint layer, and a protective top coat layer.

Paint-coated bottle

Spherulites are grown in such sections as neck, neck end, and bottom center or bottom periphery of a hollow bottle-shaped container of biaxially oriented-blow molded polyethylene terephthalate where the resin is not substantially subjected to orientation, thereby to improve the thermal resistance, stiffness and content resistance of such sections to almost the same extent as the biaxially oriented sections of the container such as shoulder and cylindrical sections thereof. The aforesaid sections of the preformed piece before being blow-molded or of the blow-molded container where the resin is not substantially subjected to orientation are first heated at 120.degree.-180.degree. C. for 3-8 minutes and then annealed at room temperature, with a result that such sections have a spherulite texture of an increased density and are opacified to white or milky white.

Method for producing polyester container

Spherulites are grown in such sections as neck, neck end, and bottom center or bottom periphery of a hollow bottle-shaped container of biaxially oriented-blow molded polyethylene terephthalate where the resin is not substantially subjected to orientation, thereby to improve the thermal resistance, stiffness and content resistance of such sections to almost the same extent as the biaxially oriented sections of the container such as shoulder and cylindrical sections thereof. The aforesaid sections of the preformed piece before being blow-molded or of the blow-molded container where the resin is not substantially subjected to orientation are first heated at 120.degree.-180.degree. C. for 3-8 minutes and then annealed at room temperatures, with a result that such sections have a spherulite texture of an increased density and are opacified to white or milky white.

A biaxially oriented bottle of saturated polyester resin has a disadvantage that the mouth or the part extending from the neck to the shoulder, which is not oriented or is oriented only a little, is much poorer in durability and resistance to the content liquid than the body which is molded under sufficient orientation. Such a disadvantage has been surmounted in this invention by covering the inside of the mouth or the part extending from the neck to the shoulder, which is in direct contact with the content liquid, with a layer which is durable and resistant to the content liquid.

Biaxially oriented bottle of saturated polyester resin

Formation of an optical design pattern in an article of polyethylene terephthalate by utilizing the property of polyethylene terephthalate to become crystallized and whitened upon slow cooling and the fact that cooling of a plastic article molded within a mold advances from the surface portion of the article in contact with the surface of the mold toward the wall of the article. Based on this theory, a desired portion of the wall of an article of polyethylene terephthalate is whitened by properly controlling the degree and speed of cooling of the polyethylene terephthalate article in the mold to cool it slowly. The whitened portion in the wall is developed as an optical design pattern that can be viewed from outside. The whitened optical design pattern developed by the aforesaid technique can be made more distinct by heat treatment and stretching treatment.

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Tokyo, Japan

Fumio Negishi