A multifunctional dual-stage melting method efficient production equipment and process

Abstract

The present application provides a multifunctional two-stage melting method high-efficiency production equipment and process, the equipment includes a frame, a storage device, a weighing device, a gathering device, a mixing mechanism, a mixing mechanism, an extrusion mechanism and a subsequent mechanism, the process includes putting the material into the storage device, after being measured by the weighing device, sending the material to the mixing mechanism through the gathering device for initial stirring and mixing, mixing and plasticizing the uniformly mixed mixture and then entering the extrusion mechanism in a semi-molten state, heating and stirring in the extrusion mechanism and then extruding in a molten state for subsequent needs such as casting or granulation, the material is formed through one-time processing, and compared with traditional equipment, the molecular structure changes of the material caused by secondary or multiple heating and plasticization of the material are reduced, and secondary contamination of the material is more effectively avoided.

Description

Technical Field

[0001] The present application relates to the technical field of breathable film production, and in particular to a multifunctional dual-stage melting method efficient production equipment and process. Background Art

[0002] Breathable membranes are widely used in personal hygiene products such as baby diapers and sanitary napkins, medical clothing, heating pads, medical protective clothing, breathable rainproof cloth, raincoats, food packaging, crop preservation, building waterproofing, desiccant bags and other fields.

[0003] In the field of breathable film production technology, blow molding and cast film are two commonly used processes. The breathable film produced by blow molding has more advantages in protecting the contents of the package and is better in tensile strength than the breathable film produced by cast film. However, it has limitations in the production process and defects that cannot be overcome by the product. For example, when performing multi-layer extrusion, the blow molding method requires the use of materials with similar fluidity to match each other as much as possible. When the fluidity of the materials differs greatly, there is a lack of corresponding measures to adjust. In addition, the stretched molecular chains of the products produced by the blow molding method will shrink significantly after being heated during the molding process, resulting in serious deformation of the product. The flatness and transparency of the product cannot be compared with the breathable film produced by the cast film method. The production process of the cast film method is very complicated and requires multiple extruders, with high equipment investment, easy material loss in the production process and low efficiency.

[0004] Patent CN111875864 discloses a polyethylene PE microporous breathable film for medical protective clothing. The breathable film is formed by three-layer co-extrusion blow molding of an outer layer, a middle layer and an inner layer by a film blowing machine, and then subjected to an eight-roller online longitudinal MDO stretching process to obtain a PE microporous breathable film; the inner layer is blended with 65-70 parts of calcium carbonate masterbatch A, 9-14 parts of metallocene polyethylene, and 1-2 parts of lubricant; the middle layer is blended with 75-80 parts of calcium carbonate masterbatch B and 20-25 parts of metallocene polyethylene; the outer layer is blended with 65-70 parts of calcium carbonate masterbatch A, 9-14 parts of metallocene polyethylene, and 1-2 parts of lubricant. The process is cumbersome and requires multiple steps of operation, and the material is easily lost during the process. The time required for shaping the breathable film prepared by the patent is relatively long, and the quality control of the product is very difficult, requiring a large amount of electricity and manpower, and its temperature resistance, that is, the heat shrinkage rate, is very low. When the product needs to be boiled and sterilized, there will be obvious shrinkage, affecting normal use.

[0005] Patent CN106397918 discloses a highly moisture-permeable polyolefin microporous breathable film, which is made of a polyolefin substrate filled with inorganic fillers, and is made into a product through cast extrusion, stretching, and heat-setting film-forming processes. However, the film prepared in this patent has uneven thickness and low tensile strength, elongation, and thermal shrinkage in the longitudinal and transverse directions, which affects the normal use of the product. Summary of the invention

[0006] In order to solve the above-mentioned technical problems, the present application provides a multifunctional two-stage melting method efficient production equipment and process.

[0007] The present application adopts the following technical scheme: a multifunctional two-stage melting method high-efficiency production equipment, including a frame, and also including a feeding mechanism arranged in sequence on the frame for feeding materials of multiple components, a mixing mechanism for initially stirring the materials fed by the feeding mechanism, a mixing mechanism for internally kneading the materials after the initial stirring by the mixing mechanism, an extrusion mechanism for extruding and granulating the materials after internal kneading by the mixing mechanism, and a molding mechanism for molding the materials after extrusion and granulation by the extrusion mechanism.

[0008] Furthermore, the feeding mechanism includes a plurality of storage devices for storing materials of various components, which solves the problem of inaccurate weighing of the weighing device at the lower end thereof due to the disparity in the ratio of the raw materials. There is no need to weigh the materials repeatedly, thus saving a lot of manpower and time. A weighing device for weighing the added materials is correspondingly arranged at the lower end of each of the storage devices. The weighing device is preferably a high-precision loss-in-weight scale with an accuracy of up to 0.2-0.5%. When weighing multiple components of raw materials with disparate ratios at the same time, the materials can be weighed quickly and accurately, and the process is convenient, fast, time-saving and labor-saving. The lower ends of the plurality of weighing devices are all connected to a collecting device for collecting the weighed materials and feeding them into the mixing mechanism.

[0009] Furthermore, the mixing mechanism is an LDH type pear-knife mixer, including a driving device and a stirring device. The stirring device is provided with a mixing inlet for receiving the material fed by the feeding mechanism, a mixing exhaust port for exhausting gas, and a mixing outlet for discharging the material after initial mixing. The LDH type pear-knife mixer has a special blade setting, so that the material converges from both ends of the cylinder to the center under the action of the inclination angle of the stirring paddle, and quickly forms a weightless state. The strong shear diffusion effect between the materials enables the materials of different components to be quickly homogenized, which can solve the problem of uneven mixing caused by the disparity in raw material ratios, large differences in specific gravity particle size and high unit volume production capacity during production.

[0010] Furthermore, the internal mixing mechanism is a closed high-precision twin-rotor continuous internal mixer, which includes an internal mixer barrel. The internal mixer barrel is provided with an internal mixing inlet for receiving the material after initial mixing by the mixing mechanism. The internal mixing inlet is a closed material receiving port to prevent powder leakage at the feed inlet and affect the final product. A internal mixing outlet for discharging the internally mixed material is provided below the internal mixer barrel. The closed high-precision twin-rotor continuous internal mixer adopts low-temperature mixing and plasticizing, which can reduce the occurrence of material carbonization, by-product precipitation, improper reaction and the like during high-temperature melting and mixing.

[0011] Furthermore, the extrusion mechanism is a meshing twin-screw extruder, which includes a barrel, and the barrel is provided with an extrusion inlet for receiving the material after the mixing of the mixing mechanism, an extrusion outlet for discharging the material after extrusion granulation, and a first exhaust port and a second exhaust port for exhausting gas. A melt pump is provided between the extrusion outlet and the barrel. The screw groove of the meshing twin-screw extruder is a non-closed structure, which is conducive to the circulation and mixing of materials. After the material passes through 10 pitches of the screw, it will be divided millions of times, and the material in the meshing area will be subjected to strong local shearing action, and the screws and the inner wall of the screw and the barrel will be subjected to strong local shearing action. The leakage flow generated by the gap between the two extruders enables the meshing twin-screws to produce a good mixing effect; the melt pump arranged on the meshing twin-screw extruder can ensure stable and efficient material decompression, ensure the uniformity and flatness of the extrusion cast film, etc., so that the extrusion amount of the material matches the production capacity of the cast film equipment to achieve a uniform and balanced production state; the second and third exhaust ports are used to remove the air in the material during the compression process of entering the twin-screw extruder, and to make the material in the barrel reach a vacuum state, reduce the surface bubbling and pinholes of the product film, and can remove the by-products in the reaction plasticization of the material and the reaction and mixing of related additives, reduce the quality of the film crystal points of the product, and ensure the stability of the product quality.

[0012] Furthermore, the molding mechanism is one or more of a casting die, a granulation die head, a casting film auxiliary machine, and a granulation pelletizer auxiliary machine, and the extrusion outlet is a three-way mechanism, which is used for filling extrusion profiles, artificial paper, engineering plastics, general material modification, and functional masterbatch production by connecting different molding mechanisms. Preferably, the three-way mechanism is connected to the casting die.

[0013] Furthermore, the mixing mechanism and the internal mixing mechanism as well as the internal mixing mechanism and the extrusion mechanism are communicated through a vertical anti-sticking pipeline.

[0014] A multifunctional two-stage melting method production process, using the multifunctional two-stage melting method high-efficiency production equipment, the production process comprises the following steps:

[0015] Step 1: Raw material preparation: Add the following components: metallocene linear low-density polyethylene, low-density high-pressure polyethylene coating, high-density polyethylene, anti-blocking agent, antioxidant, wetting agent, titanium dioxide, zinc stearate, and calcium carbonate into the feeding mechanism;

[0016] Step 2: Weighing raw materials: The feeding mechanism weighs the following parts by weight: 30-50 parts of metallocene linear low-density polyethylene, 3-10 parts of low-density high-pressure polyethylene coating, 2-8 parts of high-density polyethylene, 0.5-1 parts of anti-blocking agent, 0.2-1 parts of antioxidant, 0.1-0.5 parts of wetting agent, 0.5-1.5 parts of titanium dioxide, 0.5-1 parts of zinc stearate, 50-55 parts of calcium carbonate, and then feeds the weighed materials into the mixing mechanism;

[0017] Step 3: Initial stirring: The mixing mechanism heats the material fed by the feeding mechanism to 60-80°C, and initially stirs and mixes it at a stirring rate of 100-350r / min to obtain a preliminarily mixed mixture;

[0018] Step 4: Mixing and plasticizing: The mixing mechanism mixes and mixes the mixed material sent by the mixing mechanism. The mixing temperature is 110-120°C and the stirring rate is 550-650r / min. The mixed material is fully stirred and plasticized to obtain a semi-melted mixed material.

[0019] Step 5: Fusion extrusion: The extruder decompresses the mixed material sent by the mixer to 4-7 MPa through the metering pump, and the second and third exhaust ports are used to evacuate the air so that the inside of the cylinder reaches a vacuum state. The mixture is re-plasticized and fused at a temperature of 150-170°C and a stirring rate of 300-600 r / min to obtain a molten semi-finished product A.

[0020] Step 6: Molding: The molding mechanism plasticizes and molds the semi-finished product A extruded from the extrusion mechanism to obtain a finished product.

[0021] Furthermore, the metallocene linear low-density polyethylene has a melt index MI of 3-5 g / min;

[0022] The low-density high-pressure polyethylene coating has a melt index MI of 7-15 g / 10 min;

[0023] The high-density polyethylene has a melt index MI of 15-30 g / min;

[0024] The opening agent is one or more of oleamide, erucamide, stearamide and EBS derivatives;

[0025] The wetting agent is polyphthalamide;

[0026] The metallocene linear low-density polyethylene has excellent catalytic copolymerization ability and can be used in combination with the low-density high-pressure polyethylene coating material and high-density polyethylene for double-bond addition polymerization, so that the product forms a tighter network structure. In combination with the pear-knife mixer, three types of polyethylene with different melting coefficients and large particle size differences are mixed with fillers, thereby improving the longitudinal and transverse breaking strength and breaking elongation of the breathable film, not only significantly reducing the weight of the breathable film, but also improving the toughness of the breathable film;

[0027] The anti-blocking agent can significantly reduce the dynamic and static friction coefficient in the polyethylene system, reduce the processing energy consumption by 10-20%, effectively prevent the adhesion between breathable films and the agglomeration between granules, improve the processing and packaging efficiency and the smooth feel and surface finish, brightness and smoothness of the products;

[0028] The wetting agent polyphthalamide has the characteristics of high hardness, high strength, good chemical resistance and low cost. The wetting agent is combined with LDPE and zinc stearate, and under the vacuum decompression conditions provided by the melt pump and the exhaust port, the poor compatibility and weak bonding force of the inorganic filler and polyethylene are solved. Subsequently, in the subsequent stretching process of the film, the micropore molding quality is poor, and then the good waterproof and breathable ability of the film cannot be guaranteed. The wetting agent can effectively provide stable mechanical properties, high creep resistance and minimum deformation in the polyethylene system, and significantly improve the heat shrinkage rate of the breathable film, even the low-weight breathable film, so that the degree of shrinkage and deformation of the product due to high temperature will be smaller, the shaping effect is better, and the flatness of the product is better guaranteed, especially it is conducive to the production of positioning cut products, thereby improving the relatively hard feel and relatively poor physical properties of the positioning cut film, so that the breathable film produced by the present application is softer and skin-friendly, making the skin drier and more comfortable.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] 1. The present application provides a multifunctional two-stage melting method high-efficiency production equipment, including a frame, a material storage device, a weighing device, a collecting device, a mixing mechanism, a mixing mechanism, an extrusion mechanism and a subsequent mechanism; the material is put into the material storage device, measured by the weighing device, and then sent to the mixing mechanism through the collecting device for initial stirring and mixing, the evenly mixed mixture is plasticized by mixing and plasticizing and then enters the extrusion mechanism in a semi-molten state, and in the extrusion mechanism, it is heated and stirred and then extruded in a molten state for subsequent needs such as casting or granulation. The material is formed through one-time processing, which reduces the changes in the molecular structure of the material caused by secondary or multiple heating and plasticization of the material compared with traditional equipment, and more effectively avoids the secondary contamination of the material.

[0031] 2. By setting up multiple storage bins for storing raw materials of different components, the problem of inaccurate weighing of the weighing device at the lower end due to the disparity in raw material ratios is solved; by setting up a high-precision loss-in-weight scale instead of manual measurement, manpower and electricity are saved, and the measured raw materials are more accurate.

[0032] 3. The problem of uneven mixing caused by the disparity in raw material ratios, large differences in specific gravity and particle size, and high unit volume production capacity during production is solved by setting up an LDH pear-knife mixer.

[0033] 4. By setting a melt pump on the extrusion mechanism, the material decompression can be ensured to be stable and efficient, ensuring the uniformity and flatness of the extrusion cast film.

[0034] 5. By setting an exhaust port on the extrusion mechanism, the by-products in the material modification reaction process can be extracted, the air in the material entering the twin-screw extruder during compression can be removed, the quality of the film-forming crystal point of the product can be reduced, and the stability of the product quality can be ensured.

[0035] 6. The present application provides a two-stage melting process for producing breathable membranes, wherein the raw materials consist of 30-50 parts of metallocene linear low-density polyethylene, 3-10 parts of low-density high-pressure polyethylene coating, 2-8 parts of high-density polyethylene, 0.5-1 parts of anti-blocking agent, 0.2-1 parts of antioxidant, 0.1-0.5 parts of wetting agent, 0.5-1.5 parts of titanium dioxide, 0.5-1 parts of zinc stearate, and 50-55 parts of calcium carbonate. The raw materials used in the present application are low in cost. Since the metallocene linear low-density polyethylene has excellent catalytic copolymerization ability, it can also be combined with low-density high-pressure polyethylene coating and high-density polyethylene for double bond addition polymerization, so that the product forms a tighter network structure, thereby improving the longitudinal and transverse breaking strength and breaking elongation of the breathable membrane, which not only significantly reduces the weight of the breathable membrane, but also improves the toughness of the breathable membrane.

[0036] 7. The breathable film produced by the equipment provided by the present application can achieve higher whiteness, more uniform stretching, and low-weight products have a softer feel. The longitudinal and transverse breaking strength, longitudinal and transverse breaking elongation, hydrostatic pressure, and thermal shrinkage are much higher than those of traditional breathable films, and are conducive to the production of positioning cut products, thereby improving the relatively hard feel and relatively poor physical properties of the positioning cut film, so that the positioning cut product is softer than the traditional breathable film, and even than the thin film produced by the film blowing process, the positioning is softer, the positioning is more precise, and the physical properties are better, which can greatly save costs and resources, and has a low-carbon and environmentally friendly concept. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for describing the embodiments are briefly introduced below.

[0038] Figure 1 This is the main view of a multifunctional dual-stage melting method high-efficiency production equipment of the present application. DETAILED DESCRIPTION

[0039] like Figure 1 As shown, a multifunctional double-stage melting method high-efficiency production equipment includes a frame, and also includes a feeding mechanism for feeding materials of multiple components, a mixing mechanism for initially stirring the materials fed by the feeding mechanism, a mixing mechanism for mixing the materials after the initial mixing of the mixing mechanism, an extrusion mechanism for extruding and granulating the materials after the mixing of the mixing mechanism, and a molding mechanism for molding the materials after the extrusion and granulation of the extrusion mechanism. The molding mechanism described in Examples 1-3 is described by comparison using a casting die.

[0040] The specific technical scheme of the present invention is described below in conjunction with specific embodiments 1-3 and comparative examples:

[0041] Embodiment 1:

[0042] A multifunctional double-stage melting method production process, using the above-mentioned multifunctional double-stage melting method high-efficiency production equipment, comprises the following steps:

[0043] Step 1: Raw material preparation: Add the following components: metallocene linear low-density polyethylene, low-density high-pressure polyethylene coating, high-density polyethylene, anti-blocking agent, antioxidant, wetting agent, titanium dioxide, zinc stearate, and calcium carbonate into the feeding mechanism;

[0044] Step 2: Weighing raw materials: The feeding mechanism weighs the following parts by weight: 30 parts of metallocene linear low-density polyethylene, 3 parts of low-density high-pressure polyethylene coating material, 2 parts of high-density polyethylene, 0.5 parts of anti-blocking agent, 0.2 parts of antioxidant, 0.1 parts of wetting agent, 0.5 parts of titanium dioxide, 0.5 parts of zinc stearate, 50 parts of calcium carbonate, and then feeds the weighed materials into the mixing mechanism;

[0045] Step 3: Initial stirring: The mixing mechanism heats the material fed by the feeding mechanism to 60°C, and initially stirs and mixes it at a stirring rate of 150r / min to obtain a preliminarily mixed mixture;

[0046] Step 4: Mixing and plasticizing: The mixing mechanism mixes and mixes the mixed material sent by the mixing mechanism. The mixing temperature is 110°C and the stirring rate is 550r / min. The mixed material is fully stirred and plasticized to obtain a semi-melted mixed material.

[0047] Step 5: Fusion extrusion: The extruder decompresses the mixed material sent by the mixer to 4MPa through the metering pump, and the second and third exhaust ports are used to evacuate the air so that the inside of the cylinder reaches a vacuum state. The mixture is re-plasticized and fused at a temperature of 150°C and a stirring rate of 300r / min to obtain a molten semi-finished product A.

[0048] Step 6: Cast film: The semi-finished product A in the extrusion mechanism is passed through a casting die, extruded and cast into a film to obtain a finished product.

[0049] Embodiment 2:

[0050] A multifunctional double-stage melting method production process, using the above-mentioned multifunctional double-stage melting method high-efficiency production equipment, comprises the following steps:

[0051] Step 1: Raw material preparation: Add the following components: metallocene linear low-density polyethylene, low-density high-pressure polyethylene coating, high-density polyethylene, anti-blocking agent, antioxidant, wetting agent, titanium dioxide, zinc stearate, and calcium carbonate into the feeding mechanism;

[0052] Step 2: Weighing raw materials: The feeding mechanism weighs the following parts by weight: 40 parts of metallocene linear low-density polyethylene, 7 parts of low-density high-pressure polyethylene coating, 5 parts of high-density polyethylene, 0.8 parts of anti-blocking agent, 0.6 parts of antioxidant, 0.3 parts of wetting agent, 1 part of titanium dioxide, 0.7 parts of zinc stearate, 53 parts of calcium carbonate, and then feeds the weighed materials into the mixing mechanism;

[0053] Step 3: Initial stirring: The mixing mechanism heats the material fed by the feeding mechanism to 70°C, and initially stirs and mixes it at a stirring rate of 250r / min to obtain a preliminarily mixed mixture;

[0054] Step 4: Mixing and plasticizing: The mixing mechanism mixes and mixes the mixed material sent by the mixing mechanism. The mixing temperature is 115°C and the stirring rate is 600r / min. The mixed material is fully stirred and plasticized to obtain a semi-melted mixed material.

[0055] Step 5: Fusion extrusion: The extruder decompresses the mixed material sent by the mixer to 5MPa through the metering pump, and the second and third exhaust ports are used to evacuate the air so that the inside of the cylinder reaches a vacuum state. The mixture is re-plasticized and fused at a temperature of 160°C and a stirring rate of 400r / min to obtain a molten semi-finished product A.

[0056] Step 6: Cast film: The semi-finished product A in the extrusion mechanism is passed through a casting die, extruded and cast into a film to obtain a finished product.

[0057] Embodiment 3:

[0058] A multifunctional double-stage melting method production process, using the above-mentioned multifunctional double-stage melting method high-efficiency production equipment, comprises the following steps:

[0059] Step 1: Raw material preparation: Add the following components: metallocene linear low-density polyethylene, low-density high-pressure polyethylene coating, high-density polyethylene, anti-blocking agent, antioxidant, wetting agent, titanium dioxide, zinc stearate, and calcium carbonate into the feeding mechanism;

[0060] Step 2: Weighing raw materials: The feeding mechanism weighs the following parts by weight: 50 parts of metallocene linear low-density polyethylene, 10 parts of low-density high-pressure polyethylene coating, 8 parts of high-density polyethylene, 1 part of anti-blocking agent, 0.2 parts of antioxidant, 0.5 parts of wetting agent, 1.5 parts of titanium dioxide, 1.0 parts of zinc stearate, and 55 parts of calcium carbonate, and then feeds the weighed materials into the mixing mechanism;

[0061] Step 3: Initial stirring: The mixing mechanism heats the material fed by the feeding mechanism to 80°C, and initially stirs and mixes it at a stirring rate of 350r / min to obtain a preliminarily mixed mixture;

[0062] Step 4: Mixing and plasticizing: The mixing mechanism mixes and mixes the mixed material sent by the mixing mechanism. The mixing temperature is 120°C and the stirring rate is 650r / min. The mixed material is fully stirred and plasticized to obtain a semi-melted mixed material.

[0063] Step 5: Fusion extrusion: The extruder decompresses the mixed material sent by the mixer to 7MPa through the metering pump, and the second and third exhaust ports are used to evacuate the air so that the inside of the cylinder reaches a vacuum state. The mixture is re-plasticized and fused at a temperature of 170°C and a stirring rate of 600r / min to obtain a molten semi-finished product A.

[0064] Step 6: Cast film: The semi-finished product A in the extrusion mechanism is passed through a casting die, extruded and cast into a film to obtain a finished product.

[0065] Table 1: Weight proportions of the breathable membrane raw materials of Examples 1-3

[0066] Components Example 1 Example 2 Example 3 Metallocene linear low density polyethylene 30 40 50 Low density high pressure polyethylene coating 3 7 10 High Density Polyethylene 2 5 8 Opening agent 0.5 0.8 1 Antioxidants 0.2 0.6 1 Wetting Agents 0.1 0.3 0.5 Titanium dioxide 0.5 1.0 1.5 Zinc stearate 0.5 0.7 1.0 Calcium carbonate 50 53 55

[0067] The 15g breathable membrane prepared by the one-step method of Examples 1-3 and the comparative examples (30g breathable membrane comparative example 1 prepared by the conventional method and 35g breathable membrane comparative example 2 prepared by the conventional method) were subjected to performance comparison tests. The test items and test results are shown in Table 2:

[0068] Table 2: Examples 1-3

[0069]

[0070]

[0071] The 25g breathable membranes prepared by the one-step method of Examples 1-3 and the comparative examples (30g breathable membrane comparative example 1 prepared by the conventional method and 35g breathable membrane comparative example 2 prepared by the conventional method) were subjected to performance comparison tests. The test items and test results are shown in Table 3:

[0072]

[0073]

[0074] From the results in Table 2 and Table 3, we can see that:

[0075] 1. Comparison of the same 15g plain breathable film made by one-step method and conventional method: including longitudinal and transverse tensile strength or elongation, hydrostatic pressure, etc., the one-step method has different degrees of improvement over the conventional method, ranging from 10% to 30%, especially the transverse tensile force, which is the most critical control point of diapers, reaches 3N, and the transverse elongation reaches 500%;

[0076] 2. Compare the 13g plain weave breathable membrane produced by one-step process with the 15g plain weave breathable membrane produced by conventional process: including the comparison of longitudinal and transverse tensile force or elongation, hydrostatic pressure, etc., the 13g plain weave breathable membrane produced by one-step process and the 15g plain weave breathable membrane produced by conventional process are basically the same, especially the transverse elongation even exceeds the 15g conventional process product, reaching more than 500%;

[0077] 3. Compare the one-step 25g deep-grain pressure point breathable membrane with the conventional 30g and 35g deep-grain breathable membrane: including longitudinal and transverse tensile strength and elongation, the one-step 25g has exceeded the conventional 30g deep-grain breathable membrane, and is basically the same as the 35g deep-grain breathable membrane; especially the transverse elongation and hydrostatic pressure have exceeded the conventional 30g and 35g deep-grain breathable membrane.

[0078] 4. Compared with the conventional method, the products produced by the one-step method have a particularly improved physical property index, namely the heat shrinkage rate. Even for the low-weight breathable films of 13 and 15g, the heat shrinkage rate is less than 3%, that is, the product shrinkage deformation will be smaller, the shaping effect will be better, the flatness of the product will be better guaranteed, and it is conducive to the production of positioning cut products, thereby improving the relatively hard feel and relatively poor physical properties of the positioning cut film. Compared with the conventional method, the positioning cut product is even softer than the thin film produced by the blown film process, and the positioning is more precise, and the physical properties are better.

[0079] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A multifunctional double-stage melting method production process, using a multifunctional double-stage melting method high-efficiency production equipment, including a frame (1), characterized in that: It also comprises a feeding mechanism (2) for feeding materials of multiple components, a mixing mechanism (3) for initially stirring the materials fed by the feeding mechanism (2), a mixing mechanism (4) for internally mixing the materials after the initial mixing by the mixing mechanism (3), an extrusion mechanism (5) for extruding and granulating the materials after internal mixing by the mixing mechanism (4), and a molding mechanism (6) for molding the materials after extrusion and granulation by the extrusion mechanism (5); The mixing mechanism (3) is an LDH-type pear-knife mixer, comprising a driving device (31) and a stirring device (32); the stirring device (32) is provided with a mixing inlet (321) for receiving materials fed by the feeding mechanism (2), a mixing exhaust port (322) for exhausting gas, and a mixing outlet (323) for discharging the materials after initial mixing; The extrusion mechanism (5) is an intermeshing twin-screw extruder, and the intermeshing twin-screw extruder (5) comprises a screw barrel (51), and the screw barrel (51) is provided with an extrusion inlet (511) for receiving the material after the internal mixing mechanism (4), an extrusion outlet (53) for discharging the material after extrusion granulation, and a first exhaust port (512) and a second exhaust port (513) for discharging gas, and a melt pump (52) is provided between the extrusion outlet (53) and the screw barrel (51); The mixing mechanism (3) and the internal kneading mechanism (4) as well as the internal kneading mechanism (4) and the extrusion mechanism (5) are both connected via vertical anti-sticking pipes; The production process includes the following steps: Step 1: Raw material preparation: Add the following components: metallocene linear low-density polyethylene, low-density high-pressure polyethylene coating material, high-density polyethylene, anti-blocking agent, antioxidant, wetting agent, titanium dioxide, zinc stearate, and calcium carbonate into the feeding mechanism (2); Step 2: weighing raw materials: the feeding mechanism (2) weighs the following parts by weight: 30-50 parts of metallocene linear low-density polyethylene, 3-10 parts of low-density high-pressure polyethylene coating material, 2-8 parts of high-density polyethylene, 0.5-1 parts of anti-blocking agent, 0.2-1 parts of antioxidant, 0.1-0.5 parts of wetting agent, 0.5-1.5 parts of titanium dioxide, 0.5-1 parts of zinc stearate, and 50-55 parts of calcium carbonate, and then feeds the weighed materials into the mixing mechanism (3); Step 3: Initial stirring: The mixing mechanism (3) heats and initially stirs the materials fed by the feeding mechanism (2) to obtain a preliminarily mixed mixture; Step 4: Mixing and plasticizing: The mixing mechanism (4) mixes and mixes the mixed material fed by the mixing mechanism (3), fully stirs and plasticizes the mixed material, and obtains a semi-melted mixed material; Step 5: Fusion extrusion: The extrusion mechanism (5) re-plasticizes and fuses the mixed material fed by the mixing mechanism (4) under reduced pressure and vacuum to obtain a molten semi-finished product A; Step 6: Molding: The molding mechanism (6) plasticizes and molds the semi-finished product A extruded by the extrusion mechanism (5) to obtain a finished product; The metallocene linear low-density polyethylene has a melt index MI of 3-5 g / min; The low-density high-pressure polyethylene coating has a melt index MI of 7-15 g / 10 min; The high-density polyethylene has a melt index MI of 15-30 g / min; The opening agent is one or more of oleamide, erucamide, stearamide and EBS derivatives; The wetting agent is polyphthalamide; In step 2, the mixing temperature is 60-80°C and the stirring rate is 100-350r / min; In step 3, the mixing temperature is 110-120°C and the stirring rate is 550-650r / min; In step 4, the fusion temperature is 150-170°C, the stirring rate is 300-600r / min, and the pressure is 4-7MPa.

2. A multifunctional dual-stage melting production process according to claim 1, characterized in that: The feeding mechanism (2) comprises a plurality of storage devices (21) for storing materials of various components; a weighing device (22) for weighing the added materials is provided at the lower end of each storage device (21); and a collecting device (23) for collecting the weighed materials and feeding them into the mixing mechanism (3) is connected at the lower ends of the plurality of weighing devices (22).

3. A multifunctional dual-stage melting production process according to claim 1, characterized in that: The internal mixer mechanism (4) is a closed high-precision twin-rotor continuous internal mixer, and the internal mixer mechanism (4) comprises an internal mixer barrel (41), and the internal mixer barrel (41) is provided with an internal mixer inlet (411) for receiving the material after initial mixing by the mixing mechanism (3), and the internal mixer inlet (411) is a closed material receiving port, and a internal mixer outlet (412) for discharging the material after internal mixing is provided below the internal mixer barrel (41).

4. A multifunctional dual-stage melting production process according to claim 1, characterized in that: The forming mechanism (6) is one or more of a casting die, a granulation die head, a casting film auxiliary machine, and a granulation pelletizer auxiliary machine.

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