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Yangzhou Evergrowing Group

From synthesis to application: introduction to foam

1. How are foam plastics made? Foam plastic is a type of polymer material formed by a large number of gas micropores dispersed in solid plastic. It has the characteristics of light weight, heat insulation, sound absorption, corrosion resistance, and shock absorption, and its dielectric performance is better than that of matrix resin. Compared with pure plastic, foam plastic has low density, light weight, high specific strength (its strength increases with increasing density) and the ability to absorb impact loads. It also has excellent cushioning, shock absorption, sound insulation, and thermal conductivity. Low, good thermal insulation performance, also has excellent electrical insulation, corrosion resistance, and mildew resistance. Flexible foam has excellent elasticity and other properties. Almost all kinds of plastics can be made into foam plastics, and foam molding has become an important field of plastic processing. Cells are divided into closed cell type and open cell type. The pores in the closed cell type are isolated from each other and have floating properties; the pores in the open cell type are connected to each other and have no floating properties. It can be made of polystyrene, polyvinyl chloride, polyurethane and other resins. No matter what method is used, the basic process is foaming: ① Introduce gas into liquid or molten plastic to produce micropores; ② Make the micropores grow to a certain volume; ③Fix the microporous structure by physical or chemical methods. 2. What are the foaming methods? According to the way of introducing gas, foaming methods include mechanical, physical and chemical methods. 1. Mechanical law: With vigorous stirring, a large amount of air or other gases are introduced into the liquid plastic. In industry, this method is mainly used to produce urea-formaldehyde foam plastic, which can be used as heat insulation material or scenery material in movie theaters (such as artificial snowflakes). 2. Physical Law: 1) Dissolve low boiling point hydrocarbons or halogenated hydrocarbons into plastics: When heated, the plastic softens, and the dissolved liquid volatilizes, expands and foams. For example, polystyrene foam can be prepared by dissolving pentane into the monomer during suspension polymerization of styrene, or treating the polystyrene resin polymerized into beads with pentane under heating and pressure. The so-called expandable polystyrene beads. The beads are pre-expanded in hot water or steam, and then placed in a mold to pass steam to make the pre-expanded particles expand and fuse with each other. After cooling, a product with the same shape as the mold cavity is obtained. They are widely used as anti-shock materials in insulation and packaging. 2) Extrusion molding method can also be used: At this time, either expandable beads can be used to foam and extrude them into a sheet at one time; or ordinary polystyrene pellets can be used, and halogenated hydrocarbons are added to the appropriate part of the extruder to make them melt with the plastic. The mixing is uniform, and when the material leaves the machine head, it expands and foams. The extrusion method is often used to make sheets or plates. The sheets can be made into food packaging boxes and trays after vacuum forming. Polyethylene can also be used in a similar way to make extruded foamed products. 3) The physical methods of introducing gas include dissolution method, hollow microsphere method, etc.: The dissolution method is to mix soluble substances such as salt, starch, etc. with resin, and form a product, and then place the product in water for repeated treatments to dissolve the soluble substance to obtain an open-cell foam product, which is mostly used as a filter material. The hollow microsphere method is to mix hollow glass microspheres with a high melting temperature with a plastic melt. Under the molding conditions that the glass microspheres will not break, a special closed-cell foam can be prepared.

2021

04-25

Imported EPS foam molding machine adopts recycling technology

The recycling of waste polystyrene foam products by imported EPS foam molding machine can not only protect the environment and save energy, but also has good economic benefits. The recycling of plastic products often adopts direct utilization and conversion utilization. Recycling is an important measure to make the environment harmless, and recycling is also referred to as recycling technology. At present, many research institutes at home and abroad have conducted research on EPS recycling. Some have reached the level of practical use, while others have encountered problems of this kind or that, and they are still at the stage of experiments or small-scale experiments. In recent years, the recycling and utilization of EPS waste in my country has received the attention of relevant departments. The government and other departments have strengthened macro guidance and orderly management. Corresponding regulatory guidance and policy support policies have been issued one after another, and people’s awareness of resources and environmental protection has increased. On the whole, China has made considerable achievements in EPS recycling. For example, waste EPS is processed to produce XPS, which has become the main way for domestic EPS recycling. While the imported EPS foam molding machine has achieved results, there are still many problems: effective recycling channels have not been established, the separation and separation technology needs to be further studied and resolved, and the recycled materials have not been effectively and rationally used, resulting in a very low recovery rate. To solve the above problems, it is important to understand the problem. Recycling and recycling is not only a technical problem, but more importantly a social system engineering problem. EPS recycling should be taken as an important measure, and the waste can be recycled as much as possible. Recycling is considered to ensure the sustainable development of the national economy and the coordinated development of economy, resources and environment.

2021

04-25

Foamed concrete may become a thermal insulation material for southern buildings

Thermal insulation materials are an important factor affecting building energy conservation. At home and abroad, there is a general emphasis on the thermal insulation performance of buildings in order to greatly reduce energy consumption, thereby reducing environmental pollution and the greenhouse effect, and at the same time improving the comfort of the living environment. The energy loss of Chinese houses is roughly 50% for walls; 10% for roofs; 25% for doors and windows; and 15% for basements and floors. In order to achieve real energy conservation in buildings, all the roofs, walls, walls, and ground must be kept warm and insulated. As the initiator of the Foam Concrete Branch of China Foam Concrete and Cement Products Association, when talking about the development direction of building insulation materials in southern China, Mr. Lu Wencheng, chairman of Beijing Zhongke Zhucheng Building Materials Technology Co., Ltd. pointed out that foam concrete can be Building roofs, walls, walls, and the ground can be heat-insulated materials, and its technical characteristics are more suitable for the climatic conditions of southern China with a small temperature difference between indoor and outdoor; foam concrete can be said to be the thermal insulation of buildings in the southern region under current conditions Material. As a rising star of lightweight concrete, foam concrete is developed on the basis of aerated concrete. Since aerated concrete needs autoclave and cannot be constructed on site, although it has been used for many years, its promotion is still subject to certain restrictions, so people invented foamed concrete. Its performance and pore structure are close to that of aerated concrete, but it does not require autoclave, which is very suitable for the current environmental protection and low-carbon waste management policy and environment requirements, and can greatly reduce energy consumption. The water absorption and thermal conductivity of foamed concrete are far lower than that of aerated concrete, and it can be easily poured on any building site. In Northern Europe, North America, Sweden, Canada, Finland and other countries, the application of foamed concrete in building insulation accounts for a large proportion and is known as "building insulation clothing." Except for foamed concrete, there is no other thermal insulation material that can be widely used in various parts of the building envelope from head to toe. Foamed concrete is only able to do this because it can not only be poured on-site, but also can form various products. From the material density, it can reach an ultra-low density of 100~300kg/m3, which is close to expanded perlite. It can reach a high density of 600~1000kg/m3, and the strength can be from 0.4MP~10MPa, the thermal conductivity is 0.045~0.14 0.12W/(m·K), and the heat storage coefficient is about 3.0 W/(㎡·K) . (The smaller the thermal conductivity, the better the thermal insulation performance, and the larger the thermal storage coefficient, the better the thermal insulation performance.) In southern my country, the regional climate characteristics with small indoor and outdoor temperature differences determine residences with high thermal insulation performance and weak thermal insulation performance requirements. Therefore, good heat storage coefficient is more important than good thermal conductivity for southern residential construction. The heat storage coefficient of foamed concrete with a bulk density of 700 Kg/m3 is 3.59W/(㎡·K), and the heat storage coefficient of foamed concrete with a bulk density of 500 Kg/m3 is 2.69W/(㎡·K), which is much higher than that of organic The value of foam plastic 0.36 W/(㎡·K). Therefore, whether it is a comprehensive inspection of thermal insulation performance, thermal storage performance, freeze-thaw, strength, light weight, fire and shock resistance, environmental protection and low carbon, construction convenience, construction cost, etc., foam concrete is a building insulation material in southern my country. . At the beginning of this century, Beijing Zhongke Zhucheng focused on the development and application of building thermal insulation foamed cement insulation materials. In 2008, it was listed as the (national) building materials industry technology supervision and research center cement-based foam material research and development center. The patented product ZC inorganic foam insulation board developed by the company is a porous and lightweight inorganic board. It is made of inorganic materials such as cement, fly ash and other solid wastes. After the slurry is injected into the mold, the honeycomb foam concrete insulation board (also called foamed cement insulation board) is formed by cutting and curing after being oxidized, foamed and hardened under natural conditions.

2021

04-25

The development prospect of waste foam granulator

Judging from the current market conditions, the development prospects of waste foam pelletizers are still bright, and the market trend is very good. The output and consumption of plastic products in my country are among the top in the world, and the average annual consumption of plastics per capita is about 3 kg (in developed countries The annual consumption is eight kilograms), and the degree of white pollution ranks fourth in the world. Wherever there are people, there will be plastic waste. It is of far-reaching significance to use discarded plastic products as raw materials to process recycled pellets that are in demand on the market to achieve a virtuous cycle of resource utilization. Agricultural film, convenience bags, cement bags, food packaging bags, woven bags, beverage bottles, plastic basins, barrels, toys, sandals, vehicle bumpers, household appliances shells, etc., are all sources of raw materials for recycled particles. Doesn't dry up. Foam plastic has the characteristics of light weight, sturdiness, shock absorption, low moisture absorption, easy forming, good water resistance, heat insulation, and low price. It is an ideal material for manufacturing equipment, cold storage and central air conditioning, heat insulation and sound insulation. It is also an ideal material for all kinds of machinery, The ideal shock-proof and moisture-proof packaging for electrical appliances, electronic instruments, glass instruments, ceramic products, and craft products, or the fresh-keeping packaging of aquatic products, all use foam products. In addition, the foam board produced with foam regenerated particles is an ideal insulation in the construction field. Thermal materials, etc. For a long time, the recycling of waste foam has attracted much attention from inside and outside the industry. The huge amount of plastic waste seriously restricts our country's ecological environment. The recycling and reuse of foam waste is not only because the recycling of waste foam can play a corresponding role in environmental governance, but also the seemingly ordinary waste foam can also bring considerable profits to the enterprise through recycling. Huangxin Foam The emergence of the granulator not only injects a strong needle for companies to take the foam recovery route, but also provides a wealth of market opportunities for the foam recovery industry. The waste foam granulator turns garbage into treasures. The waste foam granulator equipment can not only turn waste foam into PS particles for manufacturing industrial raw materials, but also for investors, they can also get a lot of income every year. Investment foam Granulator equipment is a very wise project. In China, foam granulator equipment has been very common in Hebei, Anhui, Yiwu and other places. However, the application of foam granulator equipment in other areas of China is not very widespread, so It is said that foam granulator equipment has great development prospects in China

2021

04-25

Developer response: the use of foam meets national standards

News from this newspaper (trainee reporter Zhou Song) The 13th edition of this newspaper published on October 25, "Relevant departments: whether foam as a building material meets national standards for fire protection remains to be tested", reporting that the third phase of the university city Xi Street construction site uses foam as a building Building materials, citizens are suspicious. Recently, Chongqing Kaixilai Industrial Co., Ltd., the developer of the site, contacted this newspaper and provided it with the inspection report of the cast-in-place concrete hollow floor issued by the Municipal Fire Product Quality Supervision and Inspection Station. The report determined that the floor was in line with the state Fire resistance limit standard. The reporter saw in the inspection report that the samples submitted for inspection were sampled by the Shapingba District Fire Fighting Detachment on September 29 at the Xijie Street Phase III construction site in University Town and sealed up, and delivered to the Municipal Fire Product Quality Supervision and Inspection Station on October 22. The report inspection results show that the fire resistance limit of the sample reaches 90 minutes, and the fire resistance and heat insulation and fire integrity are in line with national standards. Chen Huaping, the engineering director of the project, told reporters that the current national technical standard for "Cemented Hollow Concrete Hollow Structure Forming Core Formwork" (JG/T352-2012) was formally implemented on May 1, 2012. In popular terms, the technology is to pre-embed a shaped polystyrene foam product with fireproof performance up to the design requirements in the cast-in-place concrete floor, and then pour the concrete to form the floor structure. Chen Huaping introduced that the use of this technology can reduce the weight of the building structure, increase the span of the building slab, and increase the net height of the room. Compared with ordinary cast-in-situ floor slabs, this technology also has better sound insulation and heat preservation effects.

2021

08-20

Method for improving cold-cured high-resilience molded foam products

1 Introduction Polyurethane cold-cured molded foam products are mainly used to produce car seats and headrests. Compared with hot molded products, they have simple processing technology, moderate mold temperature (45-70°C), and low energy consumption; and have excellent physical properties, Short mold time and high production efficiency. In 2012, it exceeded 19 million vehicles. The competition among the supporting auto interior companies has become increasingly fierce, and the cost of land rent, human resources, raw materials, and transportation has continued to rise, but it is difficult to absorb the increased cost in the product price. Faced with the difficulties of reality, companies can only gain space for continued survival and profitability through changes. The improvement of fast demoulding and high physical properties of the system material can greatly reduce labor costs, and can reasonably reduce the density of the product under the premise of ensuring the physical properties of the product, thereby generating new profit points. 2. Introduction For many years, TM20 (TDI/PAPI=80:20) and TM50 (TDI/PAPI= 50:50) and other TDI-rich mixed isocyanates for production, the advantages are: high TDI-rich NCO content, low P/I ratio can reduce the amount of black material, low cost; rich TDI-produced foam, Good elasticity, high tear strength, good fluidity of the system material, and relatively low product density. Disadvantages are that pure TDI is currently a highly toxic drug and is controlled by the Ministry of Public Security; TDI has a certain impact on the health of on-site operators; system materials rich in TDI mature slowly, which affects production efficiency; foams produced by rich TDI are soft. Due to the low price of TDI in recent years, from the perspective of cost, isocyanates rich in TDI are very cost-effective, and from the perspective of operator health, it is necessary to reduce the amount of TDI. The TM50 system is a relatively moderate ratio: the physical properties and cost are moderate, and the purchase is more convenient. However, it is still necessary to solve the problem of slow efficiency caused by slow maturation, insufficient foam with high physical properties, and slightly higher density. Generally speaking, slow maturation can be solved by adding foaming catalyst A1 and gel catalyst A33, but increasing the amount of A33 will cause the foam gel speed to be too fast, and it is easy to produce too late to close the mold or product flow dissatisfaction, missing corners, Undesirable phenomena such as voids can easily cause shrinkage and flatulence of the product, which will affect the performance of the foam. The physical properties of foam are generally set by OEMs. In recent years, OEMs have been continuously improving their physical properties. The most common physical properties such as tear strength must not be less than 2.0 N/cm, and those with high requirements must be greater than 2.3-2.5 N/cm; The tensile strength should not be less than 90Kpa, and the high requirements should be greater than 100-120Kpa. The compression set is increased from less than 10% to less than 5%. Under the condition that the isocyanate is relatively fixed, it is necessary to conduct research from the combined polyether component, and select the appropriate polyether, polymer polyol and crosslinking agent, silicone oil, catalyst, etc. The density is generally set by the OEM, but the general OEM will give a certain range. For example, some OEMs require a seat of 45±5Kg/m3. If the density range of 40-42 can meet the performance requirements of the OEM, This can also reduce costs. Generally reducing density is achieved by adding water. Water is a chemical blowing agent, which generates CO2 by reacting with isocyanate to generate gas, thereby reducing the density of the product. However, if there is too much water, the water-isocyanate reaction (blowing reaction) in the system will be greater than the polyol-isocyanate reaction (gel reaction), resulting in peeling, hollow center, and even bubble collapse. Therefore, when choosing a relatively fixed isocyanate system, another main raw material is polyether and polymer polyol. Fixing a polyether system is beneficial to cost control. Taking into account the basic performance requirements and cost factors of the current OEMs, polyether polyols can choose from 4800 molecular weight to 6000 molecular weight, polymer polyols can choose 3628 (28% solid content), H45 (43% solid content) and other common commonly used Types, domestic manufacturers such as Shanghai Gaoqiao, Tianjin San Petrochemical, Jinpu Kumho, Zhongshan Petrochemical, Shandong Dongda, etc. Setting such standard polyether products is easy to purchase, price is transparent, the supply chain is smooth, and the entire cost is easier to control. Under the choice of a fixed isocyanate and polyether system (330N to POP ratio), it is necessary to improve physical properties and process performance, mai

2021

08-20

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