Who can teach sponge production technology?

The production process of sponge is as follows: A. Mix foaming resin, foaming assistant and adhesive resin (to make the finished product adhesive) together; B. Perform foaming processing. Mix 80 parts of ethylene vinyl acetate (EVA), 20 parts of APAO PT 3385, 20 parts of azodicarbonamide, 19 parts of CaCO and 0.6 parts of dicumyl peroxide, and place them in a mold to foam. And use mechanical force to break the obturator cells to produce foam sponge. Its density (d) is 0.028 g/cm, and its 25% compression hardness is 1.9 KPa. Most of the ingredients of sponges are polyurethane, which is the same material as foam. Different manufacturing processes will produce different things. PU sponges mainly include polyester and polyether types, which can be sliced ??or rolled, and can also be processed and heated according to customer requirements. Press processing and blasting hole processing, etc. PU sponge is involved in various industries, including the automotive industry, battery industry, cosmetics industry, bra and underwear manufacturing industry, and high-end furniture due to its properties of heat preservation, heat insulation, sound absorption, shock absorption, flame retardant, anti-static, and good breathability. Manufacturing etc. Sponge: polyurethane soft foam rubber. Polyurethane is the most common polymer material in life and is widely used in making various "sponge" products. As well as elastic materials for shock absorption and anti-friction purposes, such as shoe soles and tractor and tank track underlays. 2. Production machines: polyurethane foaming equipment, polyurethane elastomer pouring machine, resin glue filling machine, mold bearing production line, EPS mechanical equipment: plate forming machine Vacuum plate forming machine Vacuum thickening plate forming machine Intermittent pre-expansion machine 3. Production process EPS manufacturing process 1. Process overview We generally talk about process and always refer to the molding process. In fact, when it comes to EPS molding, technology also involves raw materials and pre-expansion mechanism. , pipeline technology and system matching technology, which are ultimately reflected in the molding technology and other aspects. 2. Raw materials: 2.1 Process control of rapid materials and standard materials Rapid materials: low molecular weight and volatile content, mainly used in automatic machines and earth machinery. It contains less foaming agent and has a short curing time. During operation, the heating time is short, the cooling time is short, and the molding cycle is short, which saves energy consumption and improves production efficiency. 2.1.1. Under normal circumstances, because there is less foaming agent, it must be heated in the shortest time. Making full use of a small amount of foaming agent to bond the foam particles, the heating time is short and time is saved. Use high pressure and short time heating. 2.2.2. It can save energy consumption and improve efficiency. It adopts high temperature demoulding. The difference between molding mold temperature and demoulding temperature is small, so steam can be saved. The mold molding temperature is 115-130℃, and after water cooling to 90℃, after vacuuming, the surface expansion rate of the product is reduced to a certain value of 85℃ before it can be demoulded. Standard material: high molecular weight and volatile content. It is mainly used in soil machinery. From the perspective of energy consumption control, it is rarely used in automatic machines. 2.2 Rapid material - fast molding and saving steam 2.2.1. Rapid material types: BASF CP303, Longwang B-SB, Xingda 303, Chengda PK303, etc. Characteristics: Fast cooling speed leads to a fast molding cycle, which is generally 20-30% faster than ordinary materials. The demoulding temperature of rapid materials is high, reaching 80-85?0?2C. The demoulding temperature of traditional materials is low, 60-65?0 ?2C Therefore, rapid material can save steam up to 30%. When forming rapid material, the product bonding property should be controlled at 60-80%, which can better reflect its rapidity. Rapid material control technology: adopts high pressure and short time heating. 2.2.2. Common material types: BASF CP203, Longwang E-SB, Xingda 302, Chengda PK302, etc. Ordinary material control technology: due to its large molecular weight and high volatile content. Swelling is prone to occur during production. It is advisable to use low pressure and long time heating. 3. Pre-expansion mechanism 3.1 Foaming agent: The foaming agent of expandable polystyrene is mainly pentane, divided into n-pentane and isopentane. In the industrial product pentane, the olefin content has a great influence on the processing properties of expandable polystyrene. Too high an olefin content can easily cause product shrinkage. The higher the EPS foaming agent content, the better. Standard: 4.8-7 (≤6.8) Normally around 5. The foaming agent content is too high: the pre-foam is blooming, uneven, deformed and cracked.

The foaming agent content is too low: the foaming ratio is reduced, the heating time is too long, the adhesion between EPS beads is poor during the molding process, the product is easy to shrink and fall off, etc. 3.2 Pre-expansion principle: During the pre-foaming process, foaming The beads of the agent will not foam before 80℃, but the foaming agent in the beads will diffuse outward, and the beads will not expand at this time. When the temperature is greater than 80°C, the beads begin to soften, and the foaming agent distributed inside them is heated and vaporizes to generate pressure, causing the beads to begin to expand and form disconnected cells. At the same time, steam also penetrates into these cells, increasing the total pressure in the cells. As time goes by, the steam continues to penetrate deeper, the pressure continues to increase, and the volume of the beads also continues to increase. This process continues, and the volume expansion can be maintained until the thin wall of the cell ruptures. It can be seen that during the pre-foaming process, it is very important for steam to continuously penetrate and increase the total pressure in the pores. For example, the foaming agent opens the pores and the steam expands the pores. The speed of steam entering the cells must be greater than the speed of the foaming agent escaping from the cells. The foaming agent will not have time to completely escape from the cells, and the polymer will stretch into a rubber state, and its strength is enough to balance the internal pressure, thereby making The beads are pre-foamed. This is the simple mechanism of PS foaming. 3.3 Working principle of fluidized drying bed: The EPS coming out of the steam pre-foaming machine immediately enters the fluidized drying bed equipment and is forced to dry to facilitate the aging process. EPS enters the fluidized bed from the feed inlet. The hot air blown into the fluidized bed is sucked by the blower. After passing through the steam heater, it is blown into the fluidized bed through the bottom mesh and comes into contact with the material. The EPS pellets are in contact with the hot air and material flow. It is pushed and suspended in the air flow while drying and falling into the vibrating screen. Qualified pellets are screened and then sent to the aging silo. The agglomerated granules flow into the crushing device of the fluidized bed on the screen, which crushes the agglomerated EPS, and the qualified ones also flow into the maturation silo. There is also a compressed air interface here that is blocked. 3.4 Ripening mechanism and process control 3.4.1 Ripening mechanism: After pre-expansion, a vacuum is generated inside the EPS granules, and the surface of the EPS contains moisture, which does not meet the molding requirements. The ripening process is that air enters the EPS granules and the surface moisture dries. 3.4.2 Process control : Fast materials are generally 8 hours, ordinary materials are generally 24 hours, and high-density materials are 48 hours. The environment should be ventilated and the temperature should be greater than 10 degrees Celsius. 3.5 Pre-release Frequently Asked Questions and Solutions 3.5.1 The foam agglomeration external slip agent is not enough, and the mixer design is not good. Reasonable, the gap between the stirring blade and the chassis is too large, and there is too much water. 3.5.2 The wet cooling time of the foam particles is too short (30s). Insufficient preheating (secondary) 3.5.3 The shrinkage and foaming ratio of the foam particles is too large (the raw materials do not match) 3.5. 4. Foam particles are damaged and deformed. The magnification is too large. The conveying method is not suitable for 3.5.5. The foam magnification ratio is unstable. Reasons for the pre-expansion machine: The steam inlet mesh is blocked. Low-temperature foaming is accompanied by air that is too large and too small. The precision is not enough. Reasons for the raw materials: The particle size difference is too big. 3.5 .6 Preliminary density is too high. Feeding control is improper. 3.5.7 The measurement method of density increase after curing is incorrect. Moisture content is too high. 7. Mold acceptance attention items 7.1 Surface condition: The surface is smooth, the connection parts are smooth, and the finish is 1.6√; the air holes are not loose and Smooth, air hole center distance lt; 25mm; 7.2 The cavity plate material is selected from LY12 alloy aluminum plate, which is flat and without warping; the overall dimensions are consistent with the dimensions of the mold frame used. There is no air leakage, water leakage, or material leakage; under normal circumstances, the product has no flash. 7.3 Hole positions: The hole positions of the material gun and ejector pin are reasonably distributed to ensure sufficient material addition and easy demoulding. Pressure plate hole position: The center hole distance of Φ 36 and Φ 28 special material guns is 65mm; the center hole distance of Φ 32 is 55mm. 8. EPS molding process 8.1 Molding mechanism: The matured pre-expanded beads are heated by steam. In about 20 seconds to 60 seconds, the air has no time to escape, and the heat expands to generate pressure. The sum of the pressures is greater than the steam pressure heated outside the beads. At this time, the polymer softens and the pressure inside the cells after the blowing agent vaporizes is greater than the pressure outside. The beads expand again and fill the gaps between the beads to form a whole piece, forming a foam product with the same shape as the mold.

8.2 Brief description of key molding processes 8.2.1 Start-up preheating: This is the action of heating the mold before starting the machine. Preheating is required before the mold is closed and heated. 8.2.2 Mold closing: Reasonable adjustment of the mold opening and closing stroke is conducive to improving product demoulding. and product feeding effect. (ejector pin, mold gap) slow-speed cutting gun 8.2.3 Preheating: Steam enters the solid-moving mold to preheat the mold, so that while the mold is preheated, the condensed water and cold air remaining during the period are discharged. Function: Increase the mold temperature and enhance the apparent sintering degree of the product. 8.2.4 Penetration heating: Improve the core and internal sinterability of the product. Penetrating heating consumes and wastes steam seriously. 8.2.5 Heating on both sides: further enhance the heating effect and improve the surface quality of the product. 8.2.6 Warming (heat preservation) All valves are closed, making full use of the waste heat of the mold to heat the product. It is beneficial to the sinterability of the product surface and can better save energy (steam). 8.2.7 Pre-cooling: Open the water cooling valve and close the drain valve. Reasonably extend the pre-cooling, the product will cool faster, shorten the cooling time, and increase the molding speed. Generally, it does not exceed 10 seconds. Long pre-cooling time makes drying difficult, and the pre-cooling effect is much better than water cooling. 8.2.8 Water cooling During water cooling, the water cooling valve opens and the drain valve opens. The cooling effect of water and air is better at the same time. 8.2.9 Vacuum cooling: Open the vacuum valve and vacuum the vacuum pump. Evacuate all the residual heat and moisture in the mold and product, and remove part of the foaming agent to prevent the product from swelling. Create negative pressure in the mold, which is beneficial to product demoulding. {{The production process of sponge is as follows: A. Mix foaming resin, foaming assistant and adhesive resin (to make the finished product adhesive) together; B. Perform foaming processing. Mix 80 parts of ethylene vinyl acetate (EVA), 20 parts of APAO PT 3385, 20 parts of azodicarbonamide, 19 parts of CaCO and 0.6 parts of dicumyl peroxide, and place them in a mold to foam. And use mechanical force to break the obturator cells to produce foam sponge. Its density (d) is 0.028 g/cm, and its 25% compression hardness is 1.9 KPa. }}