R&D and design of hair straightener products

A straightener works by converting electrical energy into thermal energy. Part of the thermal energy is conducted to the low-temperature hair, while the other part is dissipated through air radiation, convection, and other means

It is absorbed by itself. A straightener, also known as an electric clamp or simply a clamp, heats the heating element MCH, PTC, or heating wire of the straightener with an electric current and conducts it to an aluminum or ceramic plate to generate heat.

A straightener, Gu Mingsiyi, is used to straighten hair by heating and softening it with a heating element, and then cooling it down to achieve the goal of straightening hair. Nowadays, straighteners can both straighten and

To roll up. Previously, hair straighteners were mainly used by professional hair salons and hairdressers. In recent years, hair straighteners have entered the Chinese home market and developed into essential personal care products, just like combs

universal. Correspondingly, there is also a curling iron that uses a heating roller for cyclic heating, improving the protein structure of hair to create bends and protecting hair quality during the curling process.

1、 Technical principle of straightener solution

1. The heating principle of a straightener

Hair straighteners generally use heating elements to raise the temperature of the working surface, causing changes in the molecular structure between keratin proteins in the hair, resulting in new shapes. Heating elements generally use positive temperature coefficient thermistor PTC (Positive Temperature Coefficient Resistance). PTC has unique electrical thermal physical properties: when an AC voltage is applied to the PTC element to raise the temperature, the resistivity is very low below the Curie temperature. When the resistivity suddenly increases beyond the Curie temperature point, the current drops to a stable value, and it has the function of automatic temperature control and constant temperature.

In recent years, electric heating wires have also been used as heating elements to pursue heating speed and efficiency. After the heating element heats up, it transfers heat to the working surface through thermal conduction to complete the perm task.

The working surface of a straightener is generally made of ceramic or aluminum plates, with aluminum plates heating up quickly but causing greater damage to hair quality than ceramic plates.

2. How to reduce the damage of straighteners to hair?

There are two factors that affect the perm effect and the degree of hair damage caused by a hair straightener: one is whether the heating method of the hair straightener is gentle and uniform, which directly affects the perm effect and the degree of hair damage. The accuracy of temperature control during the perming process is also an important factor affecting the quality of perming and hair damage. During the process of perming with a straightener, it comes into direct contact with damp hair, and its quality is related to the user's personal safety.

2、 Types of straightener solutions

Hair straighteners can be divided into ceramic heating elements, PTC heating elements, and MCH heating elements according to their different heating elements.

1. Ceramic heating element

The advantages of ceramic heating elements are environmental friendliness and fast heating speed. Generally, within 30 to 45 seconds, the surface temperature of the clamping plate can reach 200 degrees. However, due to the fact that ceramic heating elements are sintered at temperatures above 1000 degrees, their temperature will quickly exceed 300 degrees when the circuit loses control, which will burn out the plastic material that fixes the heating plate, causing the heating plate to fall off and potentially come into contact with the user, and burn the skin.

2. PTC heating element

PTC heating element, also known as PTC heater, is composed of PTC ceramic heating element and aluminum tube. This type of PTC heating element has the advantages of low thermal resistance and high heat transfer efficiency, making it an automatic constant temperature and energy-saving electric heater. The outstanding feature lies in its safety performance, and in any application, it will not produce the phenomenon of "red" on the surface of electric heating tube heaters, which may cause safety hazards such as burns and fires. PTC is also sintered at high temperatures, but the maximum temperature on its surface can be controlled during sintering. According to the manufacturer's requirements, the surface can be sintered to below 280 degrees, or any temperature desired by the manufacturer, generally to 230 to 280 degrees. But its disadvantage is that it heats up slowly to 200 degrees, usually in about a minute and a half or 2 minutes. In addition, during use, it cannot be continuously maintained at a high temperature like ceramic heating elements. The effect of straightening hair is slightly worse.

3、 Temperature rise design of electric clamp plate

The heat resistance law of insulation materials indicates that when the temperature rises to a certain level, it will cause rapid aging of the insulation material, shorten the service life of the product, reduce safety performance, and even burn the user. Standard regulation: The temperature rise at the outer surface of the molded material in short-term contact shall not exceed 60K. Due to design flaws in the structure of the straightener, heat can easily accumulate on the outer surface of the back of the working face. In addition, most manufacturers pursue a compact outer shell structure, making it difficult for heat to dissipate. Additionally, manufacturers have not taken insulation measures (such as adding insulation cotton or insulation sleeves), resulting in a temperature rise far exceeding the specified limit at the outer surface of the molded material that comes into short-term contact, which can easily cause burns to users during normal operation.

The temperature rise of the rotating connection sliding contact of the straightener is also prone to exceed the standard, because the contact area of the rotating connection contact is too small or the material resistance is too high, causing the temperature rise to exceed 65K. In recent years, hair straighteners have tended towards miniaturization, and mini perm irons have greatly increased the rate of temperature rise failure due to their more compact structure.