Pulp mouldings are paper pulps with a certain concentration, and appropriate amounts of chemical additives are added to the moulding machine by means of vacuum or pressure to evenly distribute the fibres on the surface of the mould, so as to form a wet paper mould blank with a predetermined geometric shape and size, and further Dehydration, mold removal, dry and shaped products. The product is rich in raw materials, has no pollution during production and use, has light weight, high compressive strength, good cushioning properties and good recyclability, and has a wide range of applications as a packaging product. According to relevant information, the world's output of pulp molded products has reached more than 400,000 tons. With the increasing convergence of economic convergence between China and the rest of the world, the potential for the promotion and application of pulp molded products is undoubtedly enormous.
At the end of 1991, the 12 countries of the European Community issued a mandatory enforcement standard, the "New Packaging Rules." It was clearly stated that since 1992, the use of expanded polystyrene materials in transportation packaging and sales packaging has been prohibited and pulp molded products have been replaced. Later, in the Japanese trade community, it also designated some of China's electrical export manufacturers to use paper molded products instead of expanded polystyrene packaging. For this major change in the international packaging market, China's Liaoning, Jiangsu, Guangdong, Zhejiang, Fujian and other regions have made rapid response. Although the development of China's pulp moulding products started in the 1980s and has reached a certain scale of production, the current production and operation situation is not very optimistic. There are still many areas worthy of in-depth research and improvement. The relevant issues are summarized as follows. analysis.
Second, the current pulp production process and equipment Paper pulp molding production process Paper molding production process includes waste paper sorting, shredding, slurry preparation, pulp sizing, blending slurry (concentration), product molding, product cold extrusion, product drying and product finishing, etc. .
Waste paper is one of the main raw materials for the production of injection-molded products. It is necessary to carefully classify and eliminate various kinds of adulterants by using hydraulic attritors and sorters (waste newspapers, corrugated cardboard packaging, scraps, etc.). . Grinding waste paper can be realized either in an intermittent beater or in a continuous grinder or refiner. The sorted and purified waste paper is ground and smashed into a uniform pulp. Pulp sizing is used to improve the resistance to liquid penetration of injection molded parts. For paper-type packaging products, the sizing agent is generally rosin, paraffin emulsion or rosin paraffin. Tests have shown that in order to obtain high-quality articles, non-bonded waste paper products pulp, which must be added to the dry pulp fiber equivalent to 3% of the quality of the rosin paste on the bond of waste paper products pulp, should be added 1.5 %-2% of rosin gum.
Molded products can be molded in three ways: vacuum molding, hydraulic molding, and compressed air molding. In practice, one of the above methods or as much as possible a combined method can be used to increase the production efficiency.
After filling the pulp with the model and the upper volume of the housing, the water will be discharged through the metal mesh wall of the model, and the fibers are attached to the surface of the mesh model. After molding is completed, the model is raised by means of a hydraulic cylinder, the product is taken out after compaction and transferred to the drying process. The compaction of the production is realized in a special press machine consisting of: an upper die and a lower die. The structure of the press machine should be guaranteed to be real-time; it is not stretched, otherwise it will cause the wall of the product to break. This type of equipment works on the principle that the parts are only compressed during the entire pressing process. In order to discharge the water from the place where it is pressed, it must have: vacuum suction equipment. Due to the different degree of extrusion, the moisture content of the production is between 50% and 75%, and the moisture content should be reduced to 10% (12%) in the drying process and to 3% -4% (in some cases). Drying is carried out in a drying oven in a cycle or continuous operation.The product is put on a shrinkage-proof model and fed into a drying oven.The product is dried with hot air and the temperature is 250-300°C (product within 7-10 seconds. The water content is reduced by 50%, and then the temperature is reduced to 100-105° C. The continuous drying furnace has a conveying device, and the workpieces pass through different temperature zones in the furnace, and finally dried to a moisture content of about 10%-12%. The production process of paper molding products has been accompanied by dehydration, from gravity dehydration, vacuum dehydration, press dehydration, to final thermal dehydration, ie drying. Vacuum dehydration and press dewatering remove most of the water from the product, the remaining water must Dehydration is performed by heating and drying.
After drying, it is compacted on the hot post-forming machine by extrusion, which is necessary for the uniform thickness of the wall of the injection-type packaging product, smooth and flat outer surface, and increased wall strength. Paper mouldings can be used after drying, but sometimes special treatments such as calendering, paint baking, or pattern printing on the surface are required.
Pulp molded products are used in the production of fast food products and packaging products are different in the process. Such as: disposable fast food requirements require water and oil, to meet the stiffness requirements, in line with health standards, the appearance of printing trademarks, smooth surface inside and outside clean. The general shape of the packaging products is relatively large and complex, and requires a bearing capacity, a buffer function, and a positioning function. Based on these special requirements, it is determined that the process characteristics of paper-type packaging products are: regardless of the complexity of the shape of the products, the wall thickness of the same product must be the same. Only in this way can the requirements of molding and shaping (or drying) of the products in the production process be met. . The packaging of industrial products is sometimes not too high in size and shape accuracy, and requires certain strength and cushioning. Therefore, industrial packaging of pulp molded products seldom requires stereotypes. After the molding machine is down, it is dried and molded by the dryer. This kind of drying method changes the shape and size of the product due to the precipitation of moisture from the wet paper blank. Accumulating empirical data and grasping the change law in this regard can be used as the basis for future mold design.
2. Pulp molding products production equipment According to the process requirements, the main equipment for the production of paper molding products are hydraulic pulper, pulp pool, forming machine, dryer and setting machine.
The function of the hydraulic pulper is to disintegrate the waste paperboard and turn it into pulp, which can be divided into two types, vertical and horizontal. The horizontal hydraulic pulper is commonly used in the production line of industrial packaging products. Its advantages have only dispersion effect on the paper fiber, no cutting effect, high fragmentation efficiency, short disintegration time, less work and consumption, simple structure, and can handle more Large debris, metal debris waste paper.
The molding machine is a machine that guarantees the operation of the molds for the pulping, dewatering, and removal of wet paper blanks. Its main structure includes: frame, pulp box, lift cylinder, guide column, upper and lower formwork, and air chamber fixed on the formwork (respectively communicating with vacuum system and air compressor). Although there are many forms of pulp molding machines, there are two molding processes: in-mold quantitative grouting and out-mold adsorption molding. The principle is that the pulp flows through the net mold, the water is filtered out, and the fibers are intercepted on the net mold to form a wet paper blank. In-mold grouting is to ensure the thickness of the product through a certain amount of pulp, and the outside of the mold is to ensure the thickness of the product by controlling the pulp concentration and adsorption time. Most of the paper mold industrial packaging products use reciprocating external mold adsorption molding. This molding machine can produce large area products with strong adaptability and can form an automated production line.
The dryer is recommended to use the heating method of the fuel stove. The drying structure includes the head, tail, transition section, intermediate heating section, burner, induced draft fan, transmission belt and automatic control box. During operation, the combustion furnace atomizes the diesel fuel and sprays it into the combustion chamber for combustion.
If the product shape and size requirements are very strict, the wet paper blank needs to be shaped, and the wet paper blank to be dried to a certain degree is put into the shaping die to be pressurized and heated to dry the product in the die. The setting machine is actually a small four-column press (hydraulic or pneumatic). The only difference is that the fixed mold fixed to the upper and lower platens is equipped with heating elements. The three elements of stereotypes for pulp mouldings are: 1 pressure, which requires a projected area unit pressure of 0.4-0.6mpa; 2 temperature, mold cavity temperature generally required at 180-200°C; 3 time, depending on the shape and thickness of the product, generally determined 30-50 seconds. In practice, the final thickness of the product is approximately 70% of the thickness of the mold cavity.
III. Problems and Development Countermeasures in the Production and Operation of Pulp Molded Products According to the statistics of related departments, China has an annual output of about 20 million color TVs, of which about 4 million are exported; 40 million color picture tubes are produced annually, of which 12.44 million are exported. In these two years, only about 20,000 tons of foaming material is consumed, which translates into a volume of 1 million cubic meters. Although it is difficult to have a complete statistics on the amount of foamed plastic materials consumed by other household appliances, industrial instruments, and mechanical and electrical products every year, it is undoubtedly a terrible number. The substitution of pulp molded products is an irresistible trend. It can be said that the prospects for the development of paper molded products are very promising, but at present there are still some problems in the promotion and application in China.
1. On the macro level, there is a lack of certain policy guidance and regulation. Production and applications are mostly self-distribution for enterprises and society, and there are no mandatory policies and regulations for protection. The relevant equipment and products also have no formal special standards, making it difficult for paper mold enterprises to become a dominant industry with grouping, industrialization, and standardization;
2. The problem of scattered and unregulated management in the industry. Paper mold products and equipment manufacturers are more than 200 companies involved in packaging, light industry, chemical industry, machinery, electronics, military, railway, transportation and education and other departments. Some of them lack the competent departmental enterprises, the industry management issues are ambiguous and cannot be unified, and the entire industry is in a loose state. There is no rule to follow in the actual production management and management, or everybody is right. Railways, light industry, machinery, sanitation, and some local governments have also issued some standards in succession, but they have no uniformity and therefore lack authority. At the same time, because some standards are not in line with the characteristics of the industry, many companies are at a loss as to what these plausible rules are. Some of them have to take what they want, while others ignore it. The current disorganized state makes the entire industry group lack of creativity and competitiveness, which restricts the development of the industry;
3. Paper mold product types, structure issues. At present, there is a single type of paper molding products on the market, mainly represented by fast food appliances and lining packaging. The appearance is not as complete as the plastic products and the structure is diverse. Appearance color surface quality is difficult to fully contend with plastic products. There are more than 130 enterprises engaged in the production of paper-molded tableware in China, with an annual production capacity of about 1.5 billion (600 ml standard tableware), but the loss is more than 50%, and most of them are in a half-open and half-stop state. In 1999, the annual demand for fast food was close to 10 billion, EPS cutlery accounted for 90% of the share, the remaining 10% share of cardboard cutlery, starchy cutlery, degradable plastic cutlery and paper molded tableware to compete. In China, the paper mold materials used in packaging account for only about 2% of the total amount. The total production volume is less than 5,000 tons. The European and American developed countries use more than 35% of the total packaging materials for paper packaging materials. China's packaging industry planning, by the end of this century, packaging paper products should be close to 10 million tons (including all types of cardboard), and its output value should be estimated at 50 billion yuan. According to the calculation of the maximum capacity of the existing production of paper molding products, the output gap is at least about 90%. Obviously, the great prospect of paper-molded products lies in the development of packaging products, not food and beverage supplies;
4. Paper mold manufacturing equipment and supporting mold manufacturing technology lags behind. The efficiency is low, the energy consumption is high, and the models are few. In particular, the means of manufacturing the mold is backward, the cost is high, and the efficiency is low, resulting in a single product type and a high cost.
5. The price of paper mold products is high, and Dragon has the most prominent paper molds and cutlery, which affects the chaotic situation in which the extensive use of the industry is fierce, but there are no rules to follow. As a result, the scale of production of paper molded products is small, the cost is high, and the quality is unstable, affecting its scale of formation. Benefits, it is difficult to comprehensively step the pace of industrialization.
It can be seen that although there is great potential in the market for paper molded products, the consumer market in practice needs to be nurtured. In order to make it mature, the following powerful measures should be taken:
1. The relevant departments have strengthened the construction of policies and regulations and strengthened sanctions. The enterprises of paper-molded products are given preferential treatment in terms of taxation, loans, etc., and those enterprises that are not conducive to environmental protection and are in competition with environmental protection enterprises have tightened control and imposed heavy taxes, which can really push the paper-molding industry to mature industries as soon as possible. The road
2. Relevant departments speed up the formulation of industry standards, make the products serialized, standardized, standardized, and ultimately achieve the purpose of reducing costs, saving energy, and protecting the environment;
3. Relevant departments and production companies should pay attention to the processing and marketing of paper-type packaging products;
4. Accelerate technological innovation to improve quality and reduce costs. Machine models, equipment efficiency, automatic control technology, mold design and production, process recipes, additives applications need to be comprehensive
At the end of 1991, the 12 countries of the European Community issued a mandatory enforcement standard, the "New Packaging Rules." It was clearly stated that since 1992, the use of expanded polystyrene materials in transportation packaging and sales packaging has been prohibited and pulp molded products have been replaced. Later, in the Japanese trade community, it also designated some of China's electrical export manufacturers to use paper molded products instead of expanded polystyrene packaging. For this major change in the international packaging market, China's Liaoning, Jiangsu, Guangdong, Zhejiang, Fujian and other regions have made rapid response. Although the development of China's pulp moulding products started in the 1980s and has reached a certain scale of production, the current production and operation situation is not very optimistic. There are still many areas worthy of in-depth research and improvement. The relevant issues are summarized as follows. analysis.
Second, the current pulp production process and equipment Paper pulp molding production process Paper molding production process includes waste paper sorting, shredding, slurry preparation, pulp sizing, blending slurry (concentration), product molding, product cold extrusion, product drying and product finishing, etc. .
Waste paper is one of the main raw materials for the production of injection-molded products. It is necessary to carefully classify and eliminate various kinds of adulterants by using hydraulic attritors and sorters (waste newspapers, corrugated cardboard packaging, scraps, etc.). . Grinding waste paper can be realized either in an intermittent beater or in a continuous grinder or refiner. The sorted and purified waste paper is ground and smashed into a uniform pulp. Pulp sizing is used to improve the resistance to liquid penetration of injection molded parts. For paper-type packaging products, the sizing agent is generally rosin, paraffin emulsion or rosin paraffin. Tests have shown that in order to obtain high-quality articles, non-bonded waste paper products pulp, which must be added to the dry pulp fiber equivalent to 3% of the quality of the rosin paste on the bond of waste paper products pulp, should be added 1.5 %-2% of rosin gum.
Molded products can be molded in three ways: vacuum molding, hydraulic molding, and compressed air molding. In practice, one of the above methods or as much as possible a combined method can be used to increase the production efficiency.
After filling the pulp with the model and the upper volume of the housing, the water will be discharged through the metal mesh wall of the model, and the fibers are attached to the surface of the mesh model. After molding is completed, the model is raised by means of a hydraulic cylinder, the product is taken out after compaction and transferred to the drying process. The compaction of the production is realized in a special press machine consisting of: an upper die and a lower die. The structure of the press machine should be guaranteed to be real-time; it is not stretched, otherwise it will cause the wall of the product to break. This type of equipment works on the principle that the parts are only compressed during the entire pressing process. In order to discharge the water from the place where it is pressed, it must have: vacuum suction equipment. Due to the different degree of extrusion, the moisture content of the production is between 50% and 75%, and the moisture content should be reduced to 10% (12%) in the drying process and to 3% -4% (in some cases). Drying is carried out in a drying oven in a cycle or continuous operation.The product is put on a shrinkage-proof model and fed into a drying oven.The product is dried with hot air and the temperature is 250-300°C (product within 7-10 seconds. The water content is reduced by 50%, and then the temperature is reduced to 100-105° C. The continuous drying furnace has a conveying device, and the workpieces pass through different temperature zones in the furnace, and finally dried to a moisture content of about 10%-12%. The production process of paper molding products has been accompanied by dehydration, from gravity dehydration, vacuum dehydration, press dehydration, to final thermal dehydration, ie drying. Vacuum dehydration and press dewatering remove most of the water from the product, the remaining water must Dehydration is performed by heating and drying.
After drying, it is compacted on the hot post-forming machine by extrusion, which is necessary for the uniform thickness of the wall of the injection-type packaging product, smooth and flat outer surface, and increased wall strength. Paper mouldings can be used after drying, but sometimes special treatments such as calendering, paint baking, or pattern printing on the surface are required.
Pulp molded products are used in the production of fast food products and packaging products are different in the process. Such as: disposable fast food requirements require water and oil, to meet the stiffness requirements, in line with health standards, the appearance of printing trademarks, smooth surface inside and outside clean. The general shape of the packaging products is relatively large and complex, and requires a bearing capacity, a buffer function, and a positioning function. Based on these special requirements, it is determined that the process characteristics of paper-type packaging products are: regardless of the complexity of the shape of the products, the wall thickness of the same product must be the same. Only in this way can the requirements of molding and shaping (or drying) of the products in the production process be met. . The packaging of industrial products is sometimes not too high in size and shape accuracy, and requires certain strength and cushioning. Therefore, industrial packaging of pulp molded products seldom requires stereotypes. After the molding machine is down, it is dried and molded by the dryer. This kind of drying method changes the shape and size of the product due to the precipitation of moisture from the wet paper blank. Accumulating empirical data and grasping the change law in this regard can be used as the basis for future mold design.
2. Pulp molding products production equipment According to the process requirements, the main equipment for the production of paper molding products are hydraulic pulper, pulp pool, forming machine, dryer and setting machine.
The function of the hydraulic pulper is to disintegrate the waste paperboard and turn it into pulp, which can be divided into two types, vertical and horizontal. The horizontal hydraulic pulper is commonly used in the production line of industrial packaging products. Its advantages have only dispersion effect on the paper fiber, no cutting effect, high fragmentation efficiency, short disintegration time, less work and consumption, simple structure, and can handle more Large debris, metal debris waste paper.
The molding machine is a machine that guarantees the operation of the molds for the pulping, dewatering, and removal of wet paper blanks. Its main structure includes: frame, pulp box, lift cylinder, guide column, upper and lower formwork, and air chamber fixed on the formwork (respectively communicating with vacuum system and air compressor). Although there are many forms of pulp molding machines, there are two molding processes: in-mold quantitative grouting and out-mold adsorption molding. The principle is that the pulp flows through the net mold, the water is filtered out, and the fibers are intercepted on the net mold to form a wet paper blank. In-mold grouting is to ensure the thickness of the product through a certain amount of pulp, and the outside of the mold is to ensure the thickness of the product by controlling the pulp concentration and adsorption time. Most of the paper mold industrial packaging products use reciprocating external mold adsorption molding. This molding machine can produce large area products with strong adaptability and can form an automated production line.
The dryer is recommended to use the heating method of the fuel stove. The drying structure includes the head, tail, transition section, intermediate heating section, burner, induced draft fan, transmission belt and automatic control box. During operation, the combustion furnace atomizes the diesel fuel and sprays it into the combustion chamber for combustion.
If the product shape and size requirements are very strict, the wet paper blank needs to be shaped, and the wet paper blank to be dried to a certain degree is put into the shaping die to be pressurized and heated to dry the product in the die. The setting machine is actually a small four-column press (hydraulic or pneumatic). The only difference is that the fixed mold fixed to the upper and lower platens is equipped with heating elements. The three elements of stereotypes for pulp mouldings are: 1 pressure, which requires a projected area unit pressure of 0.4-0.6mpa; 2 temperature, mold cavity temperature generally required at 180-200°C; 3 time, depending on the shape and thickness of the product, generally determined 30-50 seconds. In practice, the final thickness of the product is approximately 70% of the thickness of the mold cavity.
III. Problems and Development Countermeasures in the Production and Operation of Pulp Molded Products According to the statistics of related departments, China has an annual output of about 20 million color TVs, of which about 4 million are exported; 40 million color picture tubes are produced annually, of which 12.44 million are exported. In these two years, only about 20,000 tons of foaming material is consumed, which translates into a volume of 1 million cubic meters. Although it is difficult to have a complete statistics on the amount of foamed plastic materials consumed by other household appliances, industrial instruments, and mechanical and electrical products every year, it is undoubtedly a terrible number. The substitution of pulp molded products is an irresistible trend. It can be said that the prospects for the development of paper molded products are very promising, but at present there are still some problems in the promotion and application in China.
1. On the macro level, there is a lack of certain policy guidance and regulation. Production and applications are mostly self-distribution for enterprises and society, and there are no mandatory policies and regulations for protection. The relevant equipment and products also have no formal special standards, making it difficult for paper mold enterprises to become a dominant industry with grouping, industrialization, and standardization;
2. The problem of scattered and unregulated management in the industry. Paper mold products and equipment manufacturers are more than 200 companies involved in packaging, light industry, chemical industry, machinery, electronics, military, railway, transportation and education and other departments. Some of them lack the competent departmental enterprises, the industry management issues are ambiguous and cannot be unified, and the entire industry is in a loose state. There is no rule to follow in the actual production management and management, or everybody is right. Railways, light industry, machinery, sanitation, and some local governments have also issued some standards in succession, but they have no uniformity and therefore lack authority. At the same time, because some standards are not in line with the characteristics of the industry, many companies are at a loss as to what these plausible rules are. Some of them have to take what they want, while others ignore it. The current disorganized state makes the entire industry group lack of creativity and competitiveness, which restricts the development of the industry;
3. Paper mold product types, structure issues. At present, there is a single type of paper molding products on the market, mainly represented by fast food appliances and lining packaging. The appearance is not as complete as the plastic products and the structure is diverse. Appearance color surface quality is difficult to fully contend with plastic products. There are more than 130 enterprises engaged in the production of paper-molded tableware in China, with an annual production capacity of about 1.5 billion (600 ml standard tableware), but the loss is more than 50%, and most of them are in a half-open and half-stop state. In 1999, the annual demand for fast food was close to 10 billion, EPS cutlery accounted for 90% of the share, the remaining 10% share of cardboard cutlery, starchy cutlery, degradable plastic cutlery and paper molded tableware to compete. In China, the paper mold materials used in packaging account for only about 2% of the total amount. The total production volume is less than 5,000 tons. The European and American developed countries use more than 35% of the total packaging materials for paper packaging materials. China's packaging industry planning, by the end of this century, packaging paper products should be close to 10 million tons (including all types of cardboard), and its output value should be estimated at 50 billion yuan. According to the calculation of the maximum capacity of the existing production of paper molding products, the output gap is at least about 90%. Obviously, the great prospect of paper-molded products lies in the development of packaging products, not food and beverage supplies;
4. Paper mold manufacturing equipment and supporting mold manufacturing technology lags behind. The efficiency is low, the energy consumption is high, and the models are few. In particular, the means of manufacturing the mold is backward, the cost is high, and the efficiency is low, resulting in a single product type and a high cost.
5. The price of paper mold products is high, and Dragon has the most prominent paper molds and cutlery, which affects the chaotic situation in which the extensive use of the industry is fierce, but there are no rules to follow. As a result, the scale of production of paper molded products is small, the cost is high, and the quality is unstable, affecting its scale of formation. Benefits, it is difficult to comprehensively step the pace of industrialization.
It can be seen that although there is great potential in the market for paper molded products, the consumer market in practice needs to be nurtured. In order to make it mature, the following powerful measures should be taken:
1. The relevant departments have strengthened the construction of policies and regulations and strengthened sanctions. The enterprises of paper-molded products are given preferential treatment in terms of taxation, loans, etc., and those enterprises that are not conducive to environmental protection and are in competition with environmental protection enterprises have tightened control and imposed heavy taxes, which can really push the paper-molding industry to mature industries as soon as possible. The road
2. Relevant departments speed up the formulation of industry standards, make the products serialized, standardized, standardized, and ultimately achieve the purpose of reducing costs, saving energy, and protecting the environment;
3. Relevant departments and production companies should pay attention to the processing and marketing of paper-type packaging products;
4. Accelerate technological innovation to improve quality and reduce costs. Machine models, equipment efficiency, automatic control technology, mold design and production, process recipes, additives applications need to be comprehensive
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