In the unique world of designer toys, creative designers use toys as a medium to express their observations and thoughts about the world. In transforming abstract design concepts into tangible products, the materials and production processes used serve as a bridge between the collector and the designer, shaping the collector’s experience with the toys.
Vinyl Process
Vinyl is a manufacturing process with a long history. The first vinyl machine was built in Germany in 1924 and the first vinyl toy produced was a chocolate bunny. Many children who grew up loving toys have fond memories of vinyl toys. For example, the little yellow duck you place in the bathtub during bath time. These soft, squishy, and smooth hollow toys are made from vinyl. Vinyl toys have a unique feel and are often considered a special material, but in reality, they are made from a type of soft plastic called PVC.
Vinyl is not a material.
Vinyl is a manufacturing process. The term "vinyl" comes from the process in which "colloid" (a colloidal PVC material) is evenly applied to the inside of a mold through centrifugal rotation. PVC serves as the raw material for the vinyl process, which has two types: hard and soft. "Sofubi" is the Japanese term for "soft vinyl" which is also known as soft gelatin or Japanese soft gelatin.
Handmade vinyl toys
The price of Sofubi has risen over the years, partly due to the "handmade" appeal. The Sofubi process is quite similar to the standard vinyl process. We begin with vinyl, placing the colloidal PVC into the mold, and then closing the mold. The mold is placed in a high-temperature Rotocast oven and rotated at low speed along two vertical axes. This rotation, combined with gravity, evenly coats the inner wall of the mold with the molten plastic material. Once cooled, the finished product is removed from the mold. The main difference between the Sofubi process and the standard vinyl process is the heat-curing step. The quality of a vinyl toy also largely depends on the precise control of time and temperature during these stages.
Time-consuming, labor-intensive and costly mold-making
High-volume production relies heavily on molds. For the vinyl process, high temperatures are required and the metal molds are typically made of copper. With the rise of 3D printing technology, many art toy designs are now modeled on computers, and the master samples are directly 3D printed. However, in the traditional vinyl process, mold creation is much more complex and is generally divided into two steps: clay and wax samples.
First, clay samples are hand and machine molded to create a prototype of the design. Next, a wax model is produced based on the shape of the clay sample. Due to the approximately 3% shrinkage that occurs during the subsequent mold-turning process, the size of the wax sample is intentionally enlarged to match the intended final size.
Why use wax samples? On one hand, the surface of the wax sample is easier to polish, which results in a smooth, flat surface for the mold. On the other hand, the process follows a method similar to the ancient "lost wax" technique used in bronze casting. The wax samples are placed in an electroplating tank and copper molds are formed through an electrolytic reaction. Afterward, the mold is heated, causing the wax to melt away and leaving a hollow copper mold with the negative shape of the wax sample. This copper mold is known as the "master mold".
Even in mass production, metal molds experience wear and tear, leading to obsolescence. As a result, many production molds are often made from these master molds. The production molds are then welded to a steel frame, which facilitates the shaping of mass-produced items.
Advantages and disadvantages of vinyl toys
Imagine the flow of colloids inside the closed molds and we can better understand the various advantages and disadvantages of the vinyl process. One of the biggest advantages is the absence of parting lines, which are a common issue in injection molding. Because the vinyl mold is made in one piece, it’s possible to create a finished product without any parting lines. Additionally, vinyl toys are typically hollow due to the centrifugal force during rotation. This results in toys that are lightweight, have an elastic feel, are difficult to break, and are easy to play with, carry, and shoot for location photography. Beyond being collectible, they can also offer social functions and companionship, which may explain why many designer toys are made using the vinyl process.
However, there are also disadvantages. First, vinyl has design limitations. If the shape contains many sharp elevations and depressions, the flow of colloid inside the mold will be obstructed, leading to defects such as bubbles or material shortages. This is why most vinyl toys have simple, rounded shapes without sharp corners.
Second, every step of the process is done manually (except for the copper mold plating). This includes controlling the molding time, manually removing the product from the mold, and hand-painting the toys, since the shapes of the finished soft plastic toys vary greatly. This makes mass machine painting impossible. As a result, there is a high degree of uncertainty in the finished product, a high rate of obsolescence, and high labor costs.
Finally, because vinyl toys are made from PVC plastic, they are prone to warping, cracking, and oil absorption, which is a common issue with PVC materials.
There is no absolute superiority or inferiority when it comes to materials and production processes; each is simply chosen to complement specific products and forms of expression. The inherent imprecision of vinyl toys is, in fact, a key part of their charm and value. Additionally, the vinyl process, with its hand-coloring techniques, offers designers even greater creative freedom. This has led to the creation of many unique, limited-edition toys, further enhancing their rarity and desirability.