A blemish free surface is formed on the cavity side of a set of mold or die blocks, said set consisting of a core side and a cavity side, by use of a softer alloy on the core side as contrasted to the cavity side so that, during plastic injection molding, the core side will wear at the parting line in preference to the cavity side whereby erosion of the set occurs on the core side in preference to the cavity side leaving the cavity side erosion free.

A holding portion having a diameter larger than that of a cavity is formed in communication with the cavity, in an area of a two-part type mold, the area including a portion corresponding to an annular groove. Subsequently, an insert member formed in a cylindrical shape and provided with, on an outer circumferential surface, the annular groove having no step in a groove surface is fitted to the holding portion, and then the mold is closed. On an inner circumferential surface of the insert member, a surface treatment layer having a surface roughness rougher than those of other portions of the insert member is formed. Molten resin is injected into the cavity; thereafter, an assist material is injected into the cavity to mold the resin into a desired pipe body. Then, the insert member and the pipe body are integrated along with curing of the resin.

A holding portion having a diameter larger than that of a cavity is formed in communication with the cavity, in an area of a two-part type mold, the area including a portion corresponding to an annular groove. Subsequently, an insert member formed in a cylindrical shape and provided with, on an outer circumferential surface, the annular groove having no step in a groove surface is fitted to the holding portion, and then the mold is closed. On an inner circumferential surface of the insert member, a surface treatment layer having a surface roughness rougher than those of other portions of the insert member is formed. Molten resin is injected into the cavity; thereafter, an assist material is injected into the cavity to mold the resin into a desired pipe body. Then, the insert member and the pipe body are integrated along with curing of the resin.

A serving tray comprised of at least one synthetic material and an insert which provides a non-slip top surface of the serving tray. The textured relief is preferably made of thermoplastic polyurethane (TPU) which allows a glass or other item to be placed on the serving tray without the item sliding or slipping while the tray is in motion. The tray may be fabricated through a compression or an injection molding technique. As the tray is being fabricated, the TPU is mechanically bonded with the top surface of the tray while a textured relief is simultaneously defined into the top surface. The textured relief includes a plurality of protrusions and a corresponding plurality of indentations which provide adequate frictional force to the item being placed on the tray so as to substantially prevent its lateral movement.

A serving tray comprised of at least one synthetic material and an insert which provides a non-slip top surface of the serving tray. The textured relief is preferably made of thermoplastic polyurethane (TPU) which allows a glass or other item to be placed on the serving tray without the item sliding or slipping while the tray is in motion. As the tray is being fabricated, the TPU is mechanically bonded with the top surface of the tray while a textured relief is simultaneously defined into the top surface. The textured relief provides adequate frictional force to an item being placed on the tray so as to substantially prevent its lateral movement. The tray also includes an inner support structure disposed on its inner surface. The inner support structure provides an upward facing edge which allows a plurality of trays to be easily and efficiently stacked or nested on one another.

A serving tray comprised of at least one synthetic material and an insert which provides a non-slip top surface of the serving tray. The textured relief is preferably made of thermoplastic polyurethane (TPU) which allows a glass or other item to be placed on the serving tray without the item sliding or slipping while the tray is in motion. As the tray is being fabricated, the TPU is mechanically bonded with the top surface of the tray while a textured relief is simultaneously defined into the top surface. The textured relief provides adequate frictional force to an item being placed on the tray so as to substantially prevent its lateral movement. The tray also includes an inner support structure disposed on its inner surface. The inner support structure provides an upward facing edge which allows a plurality of trays to be easily and efficiently stacked or nested on one another.

Provided are a gradient index lens using the effective refractive index of a microstructure operating in the terahertz frequency regions and mid-infrared regions at wavelengths of 0.8 m to 3 mm and a method for manufacturing the same. Based on the effective medium theorem, the effective refractive index is controlled by using a structure smaller than the mid-infrared and terahertz wavelength, and a gradient can be provided for the refractive index in a radial direction and in an axial direction. Thus, beams in the mid-infrared and terahertz frequency region can be converged.

In order to provide a sealing element which ensures a reliable seal and which can be produced easily and economically, it is proposed that a main body of the sealing element is formed from a partially fluorinated or fully fluorinated thermoplastic material which is injection-moldable.

A resin molded product (10) includes a resin molded product main body (11), and a protrusion (12) integrally formed with the resin molded product main body (11) and protruding from the resin molded product main body (11). At injection molding of the resin molded product (10), molten resin flows through a portion (C-1) corresponding to the protrusion (12) in a cavity (C) defined by a pair of molds (20, 30). A concave portion (14) is formed on a rear side of the protrusion (12), and a bulging portion (12a) having a hollow bag shape is formed on a front side of the protrusion (12).

A resin molded product (10) includes a resin molded product main body (11), and a protrusion (12) integrally formed with the resin molded product main body (11) and protruding from the resin molded product main body (11). At injection molding of the resin molded product (10), molten resin flows through a portion (C-1) corresponding to the protrusion (12) in a cavity (C) defined by a pair of molds (20, 30). A concave portion (14) is formed on a rear side of the protrusion (12), and a bulging portion (12a) having a hollow bag shape is formed on a front side of the protrusion (12).