1 blistering technology
    1. Process principle and process
    PIP foaming technology or FIF technology process is to inject foaming material directly into the finished sleeve or leather, and use the pressure and temperature generated by foaming to make the leather close to the mold and form one-time molding. The geometry of the design is required. The specific process is divided into: 1) spraying the release agent in the cavity; 2) placing the reinforcing material or the skeleton material on the die (depending on actual needs); 3) manually opening the frame clamp of the fabric on the mold; ) stretching the leather fabric in the cavity and clamping; 5) pouring the polyurethane foaming mixture into the pre-formed fabric (either by open mold casting or closed mold casting, depending on the product); 6) After the curing time is over, the entire seat cushion is released.
    1.2 mold and leather

    Most of the molds used in the motorcycle seat cushions are metal aluminum molds. The melting point of the aluminum alloy is relatively low. The casting method of the sand mold is a relatively economical manufacturing method, and the cost is much lower than that of the steel mold. After foam molding, there will be a certain degree of shrinkage as with plastic molding. Therefore, when designing the mold, the size of the cushion mold should be designed according to the shrinkage rate of the foam. In addition, due to the low dimensional accuracy of the casting mold and the rough surface of the mold, the machining center and other equipment are required to be processed into the required size. At the same time, the polishing surface meets the roughness requirement, so a certain machining allowance is required. . The foaming reaction is a chemical process in which a blowing agent generates a large amount of gas in the reaction, which requires a good exhaust system for the mold to ensure foam performance and good appearance. The exhaust port generally opens the exhaust groove under the mold or the upper mold, and can also open the exhaust port in the upper mold. The specific size and quantity should be determined according to the product foaming lifting process, the exhaust groove or the row. In principle, the gas port should be located where the foam is finally filled with the mold. The temperature control in the foaming reaction is very important. There must be a temperature control system in the mold structure. The specific operation is to embed the stainless steel water pipe in the cast aluminum during the sand casting, and then connect the mold temperature machine to control the foaming temperature and temperature. The setting is determined according to the requirements of polyurethane raw materials. Generally, the temperature in the motorcycle seat cushion is about 55°. If it is closed mold pouring, it is necessary to fill the pouring port in the upper mold for injection. The size of the pouring port is based on the product. The size and process are fixed.

    In the cultivating technique, the mold structure is relatively simple, and only one frame type fixture is more than the above-mentioned ordinary mold (composed of the upper mold and the lower mold), and the frame clamp material is generally made by wire-cut steel plate, and the thickness and width are about 25 mm, if the shape of the frame clamp is more complicated, it is usually made of aluminum alloy material, and the process is also made of sand. Since the strength of the aluminum alloy is inferior to that of steel, the thickness and width are at least about 50 mm in order to prevent collapse.
    The leather must have good uniform adhesion with the polyurethane foam to prevent the leather from separating from the foam for a long time. The leather sleeve needs surface pretreatment, that is, the single-sided TPU film and PP are adhered to the sewing of the leather sleeve. Polypropylene) film with a thickness of less than 0.2 mm. The pre-processed face sleeve can solve the problem of bleeding of the foaming raw material at the seam of the face sleeve due to internal pressure, and improve product quality. If the unpreformed leather is used directly, the leather should be tough enough to use the pressure and temperature of the foam to make the leather close to the surface of the mold.

    1.3 Process evaluation
    The filling process has a simple structure and can be directly used after the transformation of the old mold. For the casting of the preformed holster, theoretically, various shapes of the seat cushion can be prepared, and the unformed leather can be closed mold perfusion process. Prepare some cushions with simple shapes, large rounded or rounded corners, such as bar round cushions, dental mattresses, etc. The motorcycle seat cushion is not a regular geometric shape. Generally, the process of sewing the leather first, then applying the glue and pouring, not only the process and the cost increase, but also the efficiency is low.
2 Vacuum forming technology
    2.1 Process Principles and Process
    In order to avoid the cost increase and the efficiency of the sewing holster preforming process, the vacuum integrated molding is gradually developed in the foaming technology. The process is to put the leather into the mold and use the vacuum adsorption to fit the skin to the mold. On the top, the sponge is injected into the mold with the skin and solidified to form a mold. In the past few years, many companies have also done a lot of research in this area. Now in the United States and Europe, the polyurethane molding process has been basically mature, and began to enter mass production. The process differs from the filling technique in that the vacuum integrated molding utilizes the vacuum caused by the vacuum while heating the leather to make the leather more favorable for fitting on the surface of the mold. The molding process is similar to the infusion process. The process is roughly divided into: 1) spraying the release agent in the cavity; 2) placing the reinforcing material or the skeleton material on the die (depending on actual needs); 3) manually opening the mold a frame-type jig for the upper fabric; 4) stretching the fabric in the cavity and clamping; 5) heating the fabric at a predetermined temperature (requires accurate temperature control, avoiding wrinkling and cracking of the fabric surface); 6) fabricating by vacuum suction Fully attached to the inner surface of the mold; 7) Filling the polyurethane foaming mixture into the pre-formed fabric (either by open mold casting or closed mold casting, depending on the product); 8) After curing time To demould the entire seat cushion.

    2.2 mold and leather
    The vacuum integrated molding die is more complicated. It is necessary to add a vacuum generating system to the infusion process mold. The usual method is to directly drill small holes on the surface of the lower molding or corresponding modeling features, and the lower ends of all the holes are directly and downwardly. The vacuum chamber at the bottom of the mold is connected, and the vacuum chamber is connected to the vacuum pump or the vacuum tank through the pipeline, and the valve has a valve to control the opening and closing of the vacuum. The requirements for the fabric should be: 1) have two-way ductility; 2) must be airtight coating fabric for vacuum forming and avoid foam penetration; 3) same as polyurethane foam, with good uniform adhesion.
    The overall seat produced according to the above requirements and production process can be widely used in tractors, forklifts and office supplies. The polyurethane forming process is a great progress in the foam molding process.
    2.3 Process evaluation
    Compared with the filling process, the vacuum integrated molding process avoids the complicated process of sewing the holster and improves the efficiency, but the mold structure is complicated, and the seat cushion shape has certain restrictions. The styling characteristics cannot make the leather stretch rate Large, otherwise there will be problems such as product deformation and reduced production efficiency.

    3 Leather plastic foaming technology

    3.1 Process Principles and Process
    In order to make up for the above-mentioned process deficiencies and meet the different styling requirements of the seat cushion, the leather squeezing and blistering technology is a development direction. The leather plastic foaming technology is mainly used for high-end car dashboards and other products with high requirements for visual effects and visual effects. Due to the characteristics of uniform pattern, no internal stress and high design tolerance, in recent years, molding companies have introduced plastic molding processes. The principle of leather plastic foaming technology is firstly molded into a skin conforming to the shape of the seat cushion, followed by perfusion foaming; when molding, the plastic paste is poured into the open hollow mold until the specified capacity is reached; before the filling of the mold Or heating after charging to make the material become a gel on the inner wall of the mold. When the gel reaches a predetermined thickness, the excess liquid material is poured out and heated to melt, and after cooling, the product can be taken out in the mold.
    The process of squeezing and forming foaming technology is roughly divided into 10 steps of mold clamping, heating, forming, parting, cooling, picking, rinsing, embossing, forming and demoulding, and it can directly provide the foreign companies with the required The shape of the plastic leather, so that only the process of peeling, filling, forming and demoulding is required.
    3.2 mold and leather

    The leather is made of enamel powder, and the material of the plastic skin is thermoplastic, mainly including PVC, TPU and TPO powder. PVC materials have been used for many years, the raw materials are relatively wide, and the price is relatively cheap; TPU and TPO powders are emerging materials, which are less dense than PVC powder, and contain no harmful substances and are more environmentally friendly. TPU powder combines the physical and mechanical properties of rubber, has excellent thermoplasticity and processability, is an environmentally friendly material, can be recycled and recycled; excellent physical properties, can use thin skin thickness; good chemical resistance, Anti-aging and anti-wear properties; TPU搪 plastic does not need to add plasticizer, has good odor and emission characteristics; it can maintain excellent elasticity at low temperature, and the glass transition temperature is -50 °C. The thickness of PVC plastic skin is generally 1~1.2 mm, the design freedom is high, the hand feel is good, the pattern is completely consistent with the mold, and the friction resistance is good.
    From the whole process, the plastic molding technology mold is divided into two parts: one part is used to form the plastic skin, according to the different heating methods, the gas heating mold, the oil heating mold and the sand heating mold; The mold preparation process of the plastic skin is complicated, the manufacturing is difficult, and the cost is very high. The other part is a cushion foaming mold, and the cushion foaming mold structure is substantially the same as previously described.

    3.3 Process evaluation
    The plastic blistering process can produce seat cushions of various shapes. Since the plastic skin is basically not limited by the shape, it can even be made into a certain negative angle. The rounded corner can reach 0.5 mm and the thickness is about 1.1 mm. In theory, Can be used to prepare a variety of cushions of various shapes. At the same time, since the surface pattern of the plastic leather is formed during the skin forming process, no stretching is required in the preparation of the seat cushion, and the shape of the seat cushion is not deformed, and the shape of the seat cushion is kept very good, but the energy consumption of the molding process is maintained. Large, long molding cycle, high labor intensity, long mold making cycle of the plastic molding process, not easy to modify, high cost, which is the main factor affecting the development and application of the process.