A resin part, wherein the resin part has an asymmetrical shape in a thickness direction, so that a portion in which an increase in internal temperature by heating is relatively quick is positioned closer to one end of the resin part in the thickness direction while a portion in which an increase in internal temperature by heating is relatively slow is positioned closer to the other end of the resin part in the thickness direction, wherein the resin part has an asymmetrical shape in a width direction, so that the portion in which the increase in internal temperature by heating is relatively quick is positioned closer to one end of the resin part in the width direction while a portion in which an increase in internal temperature by heating is relatively slow is positioned closer to the other end of the resin part in the width direction.

A resin part, wherein the resin part has an asymmetrical shape in a thickness direction, so that a portion in which an increase in internal temperature by heating is relatively quick is positioned closer to one end of the resin part in the thickness direction while a portion in which an increase in internal temperature by heating is relatively slow is positioned closer to the other end of the resin part in the thickness direction, wherein the resin part has an asymmetrical shape in a width direction, so that the portion in which the increase in internal temperature by heating is relatively quick is positioned closer to one end of the resin part in the width direction while a portion in which an increase in internal temperature by heating is relatively slow is positioned closer to the other end of the resin part in the width direction.

A method for producing an injection molded and anti-skid mat providing a lower mold half and an enclosing upper mold half, the mold halves defining therebetween an interior cavity which is a negative of the mat to be produced. A cavity defining surface is configured in the bottom mold half with locations for preplacement of a plurality of underside adhering portions. A flowable plasticized/rubberized material is communicated through a channel in at least one of the mold halves in order to fill the interior cavity, the material setting and cooling prior to removing the upper mold half and the formed mat.

A resin molded member for a vehicle lamp includes a first resin molded part, a second resin molded part, a bent resin molded part bent and molded to have a groove section between the first resin molded part and the second resin molded part, and a rib wall that is disposed inside the groove section and that is configured to connect between a first inclined wall and a second inclined wall which form the groove section of the bent resin molded part, wherein the rib wall is formed at a position overlapping with a gate mark which is formed on at least one of the first inclined wall and the second inclined wall through injection molding.

A resin molded member for a vehicle lamp includes a first resin molded part, a second resin molded part, a bent resin molded part bent and molded to have a groove section between the first resin molded part and the second resin molded part, and a rib wall that is disposed inside the groove section and that is configured to connect between a first inclined wall and a second inclined wall which form the groove section of the bent resin molded part, wherein the rib wall is formed at a position overlapping with a gate mark which is formed on at least one of the first inclined wall and the second inclined wall through injection molding.

A resin tank and a method for manufacturing a resin tank in which positional deviation and deformation of an inserted member is prevented. In a resin tank formed through resin injection molding, a gradually changing thickness portion in which a thickness of a resin layer gradually changes from one side to the other side with respect to a surface of an insert plate for attachment of an auxiliary component is formed in the resin layer at a region into which the insert plate is inserted.

A resin tank and a method for manufacturing a resin tank in which positional deviation and deformation of an inserted member is prevented. In a resin tank formed through resin injection molding, a gradually changing thickness portion in which a thickness of a resin layer gradually changes from one side to the other side with respect to a surface of an insert plate for attachment of an auxiliary component is formed in the resin layer at a region into which the insert plate is inserted.

A method for injection molding of a weld line free minus power lens element comprises injecting a melt of thermoplastic material at a temperature higher than a glass transition temperature (Tg) of the thermoplastic material in an initial molding cavity delimited by two facing mold inserts, wherein the melt of thermoplastic material comprises at least one UV absorber. During the injecting, the two facing mold inserts are moved toward one another to define a final molding cavity whose volume is less than that of the initial molding cavity. After cooling and disassembling of the two facing mold inserts, the weld line free minus power lens element is recovered. One of the two facing mold inserts comprises a flat surface facing the initial molding cavity, thereby to form a flat surface on one side of the weld line free minus power lens element. The other of the two facing mold inserts comprises a convex surface facing the initial molding cavity, thereby to form a concave surface on an opposite side of the weld line free minus power lens element.

The masterbatch contains a black pigment and a masterbatch thermoplastic resin, the masterbatch satisfying the following conditions: (Conditions) when a resin plate is produced by kneading 100 parts by weight of polypropylene having a melt flow rate of 30 g/10 min (JIS K7210:1999) and a density of 0.9 g/cm.sup.3 (JIS K7112:1999) with respect to 3 parts by weight of the masterbatch and subjecting the mixture to injection molding using a mold polished by a coated abrasive with a particle size of #800 (JIS R6001:1998), a* values and b* values of a surface of the resin plate in the L*a*b* color system satisfy specific conditions.

2D code patterns, such as digital watermark patterns, are formed on plastic objects by injection molding. In some implementations, a marked cell of the code pattern is not formed by a single mark on the mold surface, but by multiple discrete marks. Such marks can be exceedingly small (e.g., 50 microns or less—smaller than the width of a human hair), yet the resulting code pattern on the molded object is still readable from a distance. The small scale of the marks assures that the code pattern does not detract from object aesthetics, while also speeding the mold-marking process. Style transfer networks are employed in some implementations. The detailed technologies facilitate digital marking and identification of a great number of consumer plastic objects, thereby aiding recovery of such objects for recycling. Many other features and arrangements are also detailed.