Insoles are placed inside shoes to improve the comfort of shoes, cushion the pressure on the feet, and reduce vibration during walking or exercise. Some sports insoles can provide additional support when people are running or playing ball, protect the feet and joints, and reduce friction during exercise.
By function
• Shock-absorbing insoles: mainly used to absorb the impact force of the feet during exercise or walking, reduce the reaction force of the ground on the footsteps during running and jumping, and thus protect the feet and joints. Usually elastic materials such as silicone, EVA (ethylene-vinyl acetate copolymer) are used.
• Corrective insoles: designed to correct bad foot posture or relieve foot diseases. For example, flat foot insoles can provide additional support in the arch area, help flat foot patients reduce foot pressure and improve walking posture; there are also corrective insoles for high arch feet, inverted feet or valgus feet, etc., which can achieve the correction purpose by changing the force distribution of the foot.
• Warming insoles: the main function is to keep warm. Common ones include plush insoles, which are generally used in autumn and winter. The good thermal insulation performance of plush materials can keep the feet warm in cold weather. The materials include wool, artificial wool, etc.
According to the material
• Cotton insoles: good sweat absorption, can keep the feet dry, and relatively soft and comfortable to wear. Commonly used in shoes for daily wear, such as casual shoes, cloth shoes, etc.
• Silicone insoles: Silicone has good elasticity and flexibility, can fit the shape of the sole well, and provide comfortable support. In addition to the shock absorption function, silicone insoles also have certain anti-slip properties, which can reduce the sliding of the feet in the shoes.
• EVA insoles: light, soft and elastic, with good cushioning performance. It also has good resilience, can maintain its shape for a long time, and is not easy to be flattened. It is a common material in sports insoles.
• Leather insoles: good texture, relatively durable, and have a certain degree of breathability. Generally used in more formal shoes such as leather shoes, it can improve the overall grade of the shoes.
Insole printing methods:
1. Screen printing:
The ink or pigment is transferred to the surface of the insole through the mesh of the screen printing plate to form a pattern or text. The mesh of the image part on the screen printing plate is transparent, and the mesh of the non-image part is blocked. During printing, the scraper applies a certain pressure on the screen printing plate to squeeze the ink or pigment from the mesh of the image part to the insole.
Flat screen printing machine, rotary screen printing machine, and fully automatic screen printing machine can all be used for screen printing of insoles
2. Digital printing:
Use a digital printer to print the pattern directly on the insole. The digital printer sprays ink onto the surface of the insole through the nozzle to form an image or text. The printer can accurately print according to the computer-designed pattern without plate making. Digital printing can achieve fast proofing and personalized production; it can achieve multi-color printing and printing of complex patterns with high color reproduction; it is simple to operate, and you only need to input the designed pattern into the printer for printing.
3. Heat transfer: First print the pattern on the heat transfer paper, and then transfer the pattern on the heat transfer paper to the insole through the heat transfer equipment. During the heat pressing process, the ink or pigment on the heat transfer paper is transferred from the heat transfer paper to the surface of the insole under the action of high temperature and pressure. Heat transfer can complete rich color transfer and has a wide range of adaptability.
4. Pad printing: Pad printing is to first etch the pattern on the pad printing steel plate, then dip the pad printing ink with a silicone head, and then transfer the ink on the silicone head to the surface of the insole. During the pad printing process, the shape and hardness of the silicone head can be selected according to the shape of the insole and the printing requirements. Pad printing is suitable for printing on irregularly shaped insoles. For some insoles with complex shapes and low flatness, pad printing can better ensure the integrity of the pattern; the printing accuracy is high, and small text and patterns can be printed.
5. Hot stamping
Mainly uses the principle of heat pressing transfer. Under a certain temperature and pressure, the electrochemical aluminum foil is hot stamped onto the surface of the insole. First, the electric heating plate heats up to make the hot stamping plate have a certain amount of heat. After the electroplated aluminum is heated, the aluminum layer and the electroplated aluminum base film are peeled off and transferred to the insole. The adhesive quickly cools and solidifies, and the aluminum layer is firmly attached to the insole, completing the hot stamping process.
Semi-automatic hot stamping machines and fully automatic hot stamping machines can be well used for hot stamping of insoles.
