Composite plastic woven bag processing device and method

Abstract

The application relates to the technical field of composite plastic woven bag processing, and particularly provides a composite plastic woven bag processing device and method. The peeling force of the composite plastic woven bag can be improved. The composite plastic woven bag processing device comprises a pp flat yarn preparation unit, a woven tube cloth unit, an extrusion PE film coating unit and a cutting unit. The pp flat yarn preparation unit prepares PP polypropylene raw materials into flat yarns. The woven tube cloth unit weaves a plurality of flat yarns into pp tube cloth. The extrusion PE film coating unit coats the pp tube cloth with a PE plastic film. The cutting unit cuts the pp tube cloth coated with the PE plastic film and prepares the pp tube cloth into a composite plastic woven bag. The pp flat yarn preparation unit is provided with a hot-rolling pattern module, which can press grooves on the flat yarns, so that the bonding force of the PP woven cloth and the PE film is improved.

Description

Technical Field

[0001] This invention relates to the field of composite plastic woven bag processing technology, and specifically provides a composite plastic woven bag processing apparatus and method. Background Technology

[0002] Composite plastic woven bags are plastic bags made primarily of PP woven fabric with a PE film coating on the surface.

[0003] PE film can isolate water vapor erosion, block the leakage of fine particles and powder, and prevent acid and alkali materials from corroding woven fabrics.

[0004] Generally, the peel strength requirement for laminated woven bags is ≥3.0N / 30mm. If it is lower than this, the PE film may peel off. Once the PE film peels off, it may cause problems such as external moisture seeping into the bag and material leakage.

[0005] For long-distance transportation and repeated loading and unloading, such as under the conditions of sea storage, or when the materials inside the bag are hygroscopic or alkaline, the peel strength requirements for laminated woven bags are even higher. The conventional practice is to add 2% to 5% maleic anhydride-grafted polyolefin compatibilizer to the PE lamination, but this method has limitations for strongly alkaline materials, food, seeds, and feed. Summary of the Invention

[0006] To address the aforementioned problems, this invention provides a processing apparatus and method for composite plastic woven bags, which can improve the peel strength of composite plastic woven bags.

[0007] To achieve the above objectives, the present invention provides a composite plastic woven bag processing apparatus. The apparatus includes: a PP flat yarn preparation unit, a weaving tube fabric unit, an extrusion coating PE film unit, and a cutting unit. The PP flat yarn preparation unit prepares PP polypropylene raw materials into flat yarns; the weaving tube fabric unit weaves multiple flat yarns into PP tube fabric; the extrusion coating PE film unit coats the PP tube fabric with a PE plastic film; and the cutting unit cuts the PE-coated PP tube fabric into a composite plastic woven bag.

[0008] The PP flat filament preparation unit includes: a screw extrusion module, a water cooling module, a filament splitting module, a stretching and shaping module, a hot-rolling module, and a winding module. The screw extrusion module extrudes the PP polypropylene raw material melt into a continuous PP sheet. The water cooling module rapidly cools and shapes the PP sheet. The filament splitting module longitudinally cuts the shaped PP sheet into multiple blank filaments. The stretching and shaping module hot-stretches and shapes each blank filament to form a flat filament. The hot-rolling module hot-rolls a continuous longitudinal groove on one end face of each flat filament. The winding module winds the flat filament with the hot-rolled longitudinal groove on its surface.

[0009] The hot-rolled textured module includes a hot-rolled roll assembly, which includes a roll assembly support, hot-rolled pressure rolls, hot-rolled support rolls, and a stepper motor. Multiple hot-rolled pressure rolls are horizontally arranged within the roll assembly support. Annular protrusions are provided on the surface of each hot-rolled pressure roll. A hot-rolled support roll is provided below each hot-rolled pressure roll. The distance between the surface of the hot-rolled pressure roll and the corresponding hot-rolled support roll is consistent with the thickness of the flat wire. The height of the annular protrusion is 8% to 20% of the thickness of the flat wire.

[0010] Preferably, the temperature of the hot-rolled pressure roll and the hot-rolled idler roll is 110℃~130℃.

[0011] Preferably, the edge of the annular protrusion is smoothly connected to the roll surface of the hot-rolled pressure roll.

[0012] Preferably, the hot-rolled pattern module further includes: a fixed ceramic filament separating comb, a front flat filament leveling guide, and a rear flat filament leveling guide. The fixed ceramic filament separating comb is located at the outlet of the stretching and shaping module, with each flat filament correspondingly positioned within a limiting groove of the fixed ceramic filament separating comb. A front flat filament leveling guide is located before the inlet of the hot-rolling roll group, and the front flat filament leveling guide is configured to adjust the deflection angle of each flat filament, ensuring that the flat filament enters horizontally between the hot-rolling pressure roll and the hot-rolling idler roll. A rear flat filament leveling guide is located after the outlet of the hot-rolling roll group, and the rear flat filament leveling guide is configured to ensure that each flat filament is horizontal between the hot-rolling pressure roll and the hot-rolling idler roll.

[0013] The flat wire leveling guide includes a conical opening and a limiting cavity. The conical opening is a conical structure with openings at both ends. The limiting cavity includes a box-shaped body with openings at both ends whose cross-section is adapted to the cross-section of the flat wire. The flat wire and the limiting cavity are in clearance fit.

[0014] The small-diameter opening end of the conical opening is connected to one end of the limiting cavity, and the inner wall of the conical opening is smoothly connected to the inner wall of the limiting cavity.

[0015] Preferably, the surface of the hot-rolled roller is provided with 1 to 3 annular protrusions.

[0016] Preferably, the cross-section of the annular protrusion includes a trapezoid and a minor arc shape, wherein the trapezoid is an isosceles trapezoid, and the wide base of the trapezoid is coplanar with the roll surface of the hot-rolled pressure roll, and the narrow base of the trapezoid is collinear with the chord of the minor arc shape.

[0017] On the other hand, the present invention also provides a method for processing composite plastic woven bags, applicable to the aforementioned composite plastic woven bag processing apparatus. The method for processing composite plastic woven bags includes:

[0018] S1. Obtain raw materials and feed them into the PP flat yarn preparation unit after formulating the raw materials. The PP flat yarn preparation unit is heated and melted by the screw, and the film is extruded through the die head. After water cooling, it is rapidly shaped into a plastic film.

[0019] S2. The plastic film is fed into a process where it is divided into multiple strip-shaped blanks.

[0020] S3. After heating multiple blank wires to 110℃~130℃ in an oven, perform 5~7 times unidirectional hot stretching, and then heat set and bake at 110℃~130℃ to obtain flat wires.

[0021] S4. Flat wires with a surface temperature of 80℃~105℃ are hot rolled at a roll temperature of 110℃~130℃ to form 1~3 grooves along the extension direction of the flat wire on one end face.

[0022] S5. The flat wire with rolled grooves is wound up after being air-cooled.

[0023] S6. Use grooved flat yarns to weave PP tubular fabric, and keep the grooves facing the same side of the PP tubular fabric.

[0024] S7. After corona treatment on one side of the PP tubular fabric with grooves, coat it with PE film.

[0025] S8. Complete the roll-up.

[0026] Preferably, the thickness of the flat wire is 60~80μm, and the depth of the groove is 6.4μm~16μm. The opening width of the groove is 30μm~50μm, and the bottom plate width of the groove is 35μm~55μm.

[0027] The above technical solution has the following advantages or beneficial effects:

[0028] This invention provides a composite plastic woven bag, which uses PP woven fabric and coated PE film. Both PP woven fabric and PE film belong to non-polar polyolefins. Their molecules do not have strong polar functional groups. Van der Waals forces are the main interaction at the interface. There are no hydrogen bonds or chemical bonds. Their natural adhesive ability is poor. Relying solely on hot-pressing and melting composite, the upper limit of peel strength is not high.

[0029] The PP woven fabric of this invention has grooves designed on its surface. After spraying PE melt, it is subjected to high pressure and cooling, which allows the PE melt to embed into the grooves. Furthermore, due to the woven structure of the fabric, more PE melt can be guided into the area below the PP flat yarns, thus achieving physical and mechanical embedding and improving the peel force of the composite plastic woven bag. Attached Figure Description

[0030] The invention, its features, shape, and advantages will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings. Like reference numerals denote like parts throughout the drawings, which are not intentionally drawn to scale; the focus is on illustrating the spirit of the invention.

[0031] Figure 1 This is a structural diagram of the PP flat wire preparation unit of the present invention;

[0032] Figure 2 This is a structural diagram of the hot-rolled textured module of the present invention;

[0033] Figure 3 This is a structural diagram of the hot rolling roll assembly of the present invention;

[0034] Figure 4 This is a cross-sectional view of the front flat wire leveling guide of the present invention. Detailed Implementation

[0035] The following detailed description of the embodiments, with reference to the accompanying drawings, aims to help those skilled in the art to have a more complete, accurate, and in-depth understanding of the concept and technical solutions of the present invention, and to facilitate its implementation, but is not intended to limit the present invention.

[0036] See appendix Figures 1-4 As shown, this invention provides a composite plastic woven bag processing apparatus. The apparatus includes: a PP flat yarn preparation unit, a weaving tube fabric unit, an extrusion coating PE film unit, and a cutting unit. The PP flat yarn preparation unit prepares PP polypropylene raw materials into flat yarns; the weaving tube fabric unit weaves multiple flat yarns into PP tube fabric; the extrusion coating PE film unit coats the PP tube fabric with a PE plastic film; and the cutting unit cuts the PE-coated PP tube fabric into a composite plastic woven bag.

[0037] The PP flat filament preparation unit includes: a screw extrusion module 1, a water cooling module 2, a filament splitting module 3, a stretching and shaping module 4, a hot-rolling groove module 5, and a winding module. The screw extrusion module 1 extrudes the PP polypropylene raw material melt into a continuous PP sheet. The water cooling module 2 rapidly cools and shapes the PP sheet. The filament splitting module 3 longitudinally cuts the shaped PP sheet into multiple blank filaments. The stretching and shaping module 4 hot-stretches and shapes each blank filament to form a flat filament. The hot-rolling groove module 5 hot-rolls a continuous longitudinal groove on one end face of each flat filament. The winding module winds the flat filament with the hot-rolled longitudinal groove on its surface.

[0038] The hot-rolled textured module 5 includes a hot-rolled roll group 51, which includes a roll group support, hot-rolled pressure rolls 52, hot-rolled support rolls 53, and a stepper motor. Multiple hot-rolled pressure rolls 52 are horizontally arranged in the roll group support. The roll surface of each hot-rolled pressure roll 52 is provided with annular protrusions. A hot-rolled support roll 53 is provided below each hot-rolled pressure roll 52. The distance between the roll surface of the hot-rolled pressure roll 52 and the roll surface of the corresponding hot-rolled support roll 53 is consistent with the thickness of the flat wire. The height of the annular protrusion is 8% to 20% of the thickness of the flat wire.

[0039] Preferably, the temperature of the hot-rolled pressure roll 52 and the hot-rolled idler roll 53 is 110℃~130℃.

[0040] Preferably, the edge of the annular protrusion is smoothly connected to the roll surface of the hot-rolled pressure roll 52.

[0041] The hot rolling pressure roll 52 is driven by a speed reduction stepper motor, and the hot rolling idler roll 53 keeps in sync with the hot rolling pressure roll 52 through a synchronous reversing gear.

[0042] Preferably, the hot-rolled textured module 5 further includes: a fixed ceramic filament comb 54, a front flat filament leveling guide 55, and a rear flat filament leveling guide 56. The fixed ceramic filament comb 54 is disposed at the outlet of the stretching and shaping module 4, and each flat filament is correspondingly disposed in a limiting groove of the fixed ceramic filament comb 54. A front flat filament leveling guide 55 is disposed before the inlet of the hot-rolling roll group 51. The front flat filament leveling guide 55 is configured to adjust the deflection angle of each flat filament so that the flat filament enters horizontally between the hot-rolling pressure roll 52 and the hot-rolling support roll 53. A rear flat filament leveling guide 56 is disposed after the outlet of the hot-rolling roll group 51. The rear flat filament leveling guide 56 is configured to ensure that each flat filament is horizontal between the hot-rolling pressure roll 52 and the hot-rolling support roll 53.

[0043] The front flat wire leveling guide 55 includes a conical opening and a limiting cavity. The conical opening is a conical structure with openings at both ends. The limiting cavity includes a box-shaped body with openings at both ends whose cross-section is adapted to the cross-section of the flat wire. The flat wire and the limiting cavity are in clearance fit.

[0044] The structure of the rear flat wire leveling guide 56 is the same as that of the front flat wire leveling guide 55. Both keep the flat wire horizontal and in the entry position between the hot rolling pressure roller 52 and the hot rolling support roller 53, and ensure that grooves are pressed out on the horizontal end face of each flat wire.

[0045] The small-diameter opening end of the conical opening is connected to one end of the limiting cavity, and the inner wall of the conical opening is smoothly connected to the inner wall of the limiting cavity.

[0046] Both the front flat wire leveling guide 55 and the rear flat wire leveling guide 56 are made of smooth mirror ceramic to reduce friction on the flat wire.

[0047] Both the hot-rolled pressure roll 52 and the hot-rolled idler roll 53 are made of steel mirror-finish rolls.

[0048] Preferably, the surface of the hot-rolled roller 52 is provided with 1 to 3 annular protrusions.

[0049] Preferably, the cross-section of the annular protrusion includes a trapezoid and a minor arc shape, wherein the trapezoid is an isosceles trapezoid, and the wide base of the trapezoid is coplanar with the roll surface of the hot rolling roll 52, and the narrow base of the trapezoid is collinear with the chord of the minor arc shape.

[0050] The annular protrusion structure can prevent the width of the groove opening from being smaller than the width of the groove bottom plate due to the air cooling of the flat wire (the two places have different shrinkage rates), which can facilitate the entry of PE melt into the groove and facilitate the extrusion of air from the PE melt in the groove after extrusion, thus preventing air bubbles.

[0051] The woven tubular fabric unit, extrusion coated PE film unit, cutting unit, screw extrusion module 1, water cooling module 2, filament splitting module 3, stretching and shaping module 4, and winding module of the present invention are all prior art and will not be described in detail here.

[0052] In addition, a corona treatment machine needs to be set up in the extrusion coating PE film unit to increase the surface tension of the PP woven fabric and improve the interfacial adhesion strength with the melt PE film layer.

[0053] In this invention, after the blank wire is hot-stretched and shaped, it is hot-rolled again to form stripes. The height of the annular protrusion is 8% to 20% of the thickness of the flat wire. This is a surface micro-tightening pattern. Only the surface is extruded, and the flat wire is not thinned as a whole.

[0054] Furthermore, because the flat yarn is stretched by 5 to 7 times, meaning it is 5 to 7 times the size of a uniaxially oriented PP flat yarn, and the molecular chain height is oriented longitudinally, the transverse plastic deformation capacity of the flat yarn is poor after hot rolling grooves and remains basically unchanged.

[0055] Therefore, the addition of the hot-rolled textured module 5 to the PP flat yarn preparation unit of the present invention will not have a significant impact on the subsequent weaving tube fabric unit. That is, the weaving tube fabric unit can continue to operate using the previous parameters without any adaptive adjustments.

[0056] The thickness of the flat wire in this invention is generally 60-80 μm, and the optimal groove depth is 6 μm-12 μm. Specifically, when the flat wire thickness is 60 μm, the groove depth is 6-10 μm, and when the flat wire thickness is 80 μm, the groove depth is 8-12 μm. If the groove is too deep, it will affect the tensile strength of the flat wire; if the groove is too shallow, it will not form an effective mechanical bond.

[0057] On the other hand, the present invention also provides a method for processing composite plastic woven bags, applicable to the aforementioned composite plastic woven bag processing apparatus. The method for processing composite plastic woven bags includes:

[0058] S1. Obtain raw materials and feed them into the PP flat yarn preparation unit after formulating the raw materials. The PP flat yarn preparation unit is heated and melted by the screw, and the film is extruded through the die head. After water cooling, it is rapidly shaped into a plastic film.

[0059] S2. The plastic film is fed into a process where it is divided into multiple strip-shaped blanks.

[0060] S3. After heating multiple blank wires to 110℃~130℃ in an oven, perform 5~7 times unidirectional hot stretching, and then heat set and bake at 110℃~130℃ to obtain flat wires.

[0061] S4. Flat wires with a surface temperature of 80℃~105℃ are hot rolled at a roll temperature of 110℃~130℃ to form 1~3 grooves along the extension direction of the flat wire on one end face.

[0062] S5. The flat wire with rolled grooves is wound up after being air-cooled.

[0063] S6. Use grooved flat yarns to weave PP tubular fabric, and keep the grooves facing the same side of the PP tubular fabric.

[0064] S7. After corona treatment on one side of the PP tubular fabric with grooves, coat it with PE film.

[0065] S8. Complete the roll-up.

[0066] Preferably, the thickness of the flat wire is 60~80μm, and the depth of the groove is 6.4μm~16μm. The opening width of the groove is 30μm~50μm, and the bottom plate width of the groove is 35μm~55μm.

[0067] In this invention, compared with the prior art, the composite plastic woven bag adds steps S4 and S5 after the raw yarn is subjected to unidirectional thermal stretching.

[0068] Given that this process has little impact on the overall width and thickness of the flat yarn, with the width increase being between 1% and 2%, it does not affect the operation of the flat yarn cylindrical loom, so there is no need to make any adjustments to the parameters or other processes.

[0069] The overall process of this invention is easy to adjust. According to experiments, the peel strength of existing composite plastic woven bags using PP woven fabric and PE coating is generally 1.8N / 15mm to 2.6N / 15mm. The peel strength of composite plastic woven bags using PP woven fabric and PE coating with a small amount of graft compatibilizer is generally 2.8N / 15mm to 3.5N / 15mm.

[0070] For composite plastic woven bags made of PP woven fabric and PE coated fabric with groove depth of 8%~20%, continuous stripes along the extension direction of flat yarn, pitch of 0.4mm~1.2mm, and aspect ratio of 0.15~0.35 (PP woven fabric corona treated), the peel force reached 4.2N / 15mm~6.0N / 15mm. In some samples, the PE coated layer body tore during the peeling process and no longer simply separated along the two-phase interface.

[0071] Overall, pressing grooves into flat yarns can significantly improve the bonding strength between PP woven fabric and PE coating, and enhance the peel strength of composite plastic woven bags.

[0072] In the description of this specification, specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.

[0073] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A composite plastic woven bag processing device, characterized in that, include: The system includes a PP flat yarn preparation unit, a weaving tube fabric unit, an extrusion coating PE film unit, and a cutting unit. The PP flat yarn preparation unit prepares PP polypropylene raw materials into flat yarns. The weaving tube fabric unit weaves multiple flat yarns into PP tube fabric. The extrusion coating PE film unit coats the PP tube fabric with a PE plastic film. The cutting unit cuts the PP tube fabric coated with the PE plastic film and prepares it into a composite plastic woven bag. The PP flat filament preparation unit includes: a screw extrusion module, a water cooling module, a filament splitting module, a stretching and shaping module, a hot-rolling module, and a winding module. The screw extrusion module extrudes the PP polypropylene raw material melt into a continuous PP sheet. The water cooling module rapidly cools and shapes the PP sheet. The filament splitting module longitudinally cuts the shaped PP sheet into multiple blank filaments. The stretching and shaping module hot-stretches and shapes each blank filament to form a flat filament. The hot-rolling module hot-rolls a continuous longitudinal groove on one end face of each flat filament. The winding module winds the flat filament with the hot-rolled longitudinal groove on its surface. The hot-rolled textured module includes a hot-rolled roll assembly, which includes a roll assembly support, hot-rolled pressure rolls, hot-rolled support rolls, and a stepper motor. Multiple hot-rolled pressure rolls are horizontally arranged within the roll assembly support. Annular protrusions are provided on the surface of each hot-rolled pressure roll. A hot-rolled support roll is provided below each hot-rolled pressure roll. The distance between the surface of the hot-rolled pressure roll and the corresponding hot-rolled support roll is consistent with the thickness of the flat wire. The height of the annular protrusion is 8% to 20% of the thickness of the flat wire.

2. The composite plastic woven bag processing device according to claim 1, characterized in that, The temperature of the hot-rolled pressure roll and the hot-rolled idler roll is 110℃~130℃.

3. The composite plastic woven bag processing device according to claim 1, characterized in that, The edge of the annular protrusion is smoothly connected to the surface of the hot-rolled pressure roll.

4. The composite plastic woven bag processing device according to claim 1, characterized in that, The hot-rolled textured module also includes: a fixed ceramic filament comb, a front flat filament leveling guide, and a rear flat filament leveling guide; The fixed ceramic filament splitting comb is located at the outlet of the stretching and shaping module, and each flat filament is correspondingly set in a limiting groove of the fixed ceramic filament splitting comb; A front flat wire leveling guide is provided before the inlet of the hot rolling roll group. The front flat wire leveling guide is configured to adjust the deflection angle of each flat wire so that the flat wire enters horizontally between the hot rolling pressure roll and the hot rolling support roll. A rear flat wire leveling guide is provided after the front end of the hot rolling roll group exit. The rear flat wire leveling guide is configured to ensure that each flat wire is horizontal between the hot rolling pressure roll and the hot rolling support roll. The flat wire leveling guide includes a conical opening and a limiting cavity. The conical opening is a conical structure with openings at both ends. The limiting cavity includes a box-shaped body with openings at both ends whose cross-section is adapted to the cross-section of the flat wire. The flat wire and the limiting cavity are in clearance fit. The small-diameter opening end of the conical opening is connected to one end of the limiting cavity, and the inner wall of the conical opening and the inner wall of the limiting cavity are smoothly connected.

5. The composite plastic woven bag processing device according to claim 1, characterized in that, The surface of the hot-rolled roller is provided with 1 to 3 annular protrusions.

6. The composite plastic woven bag processing device according to claim 1, characterized in that, The cross-section of the annular protrusion includes a trapezoid and a minor arc shape. The trapezoid is an isosceles trapezoid, and the wide base of the trapezoid is coplanar with the roll surface of the hot-rolled pressure roll. The narrow base of the trapezoid is collinear with the chord of the minor arc shape.

7. A method for processing composite plastic woven bags, applicable to the composite plastic woven bag processing apparatus described in claims 1-6, characterized in that, The processing method for the composite plastic woven bag includes: S1. Obtain raw materials and feed them into the PP flat yarn preparation unit after formulating the raw materials. The PP flat yarn preparation unit is heated and melted by the screw, and the film is extruded through the die head. After water cooling, it is rapidly shaped into a plastic film. S2. The plastic film is fed into a strip-shaped blank wire; S3. After heating multiple blank wires to 110℃~130℃ in an oven, perform 5~7 times unidirectional hot stretching, and then perform heat setting and baking at 110℃~130℃ to obtain flat wires. S4. Flat wire with a surface temperature of 80℃~105℃ is hot rolled at a roll temperature of 110℃~130℃ to make 1~3 grooves rolled on one end face of the flat wire along the extension direction of the flat wire. S5. The flat wire with rolled grooves is wound up after being air-cooled. S6. Use grooved flat yarn to weave PP tubular fabric, and keep the groove facing the same side of the PP tubular fabric. S7. After corona treatment of one side of the PP tubular fabric belt with grooves, a PE film is coated on it. S8. Complete the roll-up.

8. The method for processing composite plastic woven bags according to claim 7, characterized in that, The thickness of the flat wire is 60~80μm, and the depth of the groove is 6.4μm~16μm; The opening width of the trench is 30μm to 50μm, and the bottom plate width of the trench is 35μm to 55μm.

Images