Multi-layer co-extrusion die head for biodegradable mulching film

Abstract

The utility model discloses a multi-layer co-extrusion die head for biodegradable mulching film, which relates to the technical field of mulching film production equipment and comprises a plurality of die head components, each die head component comprises an upper die head and a lower die head fixedly connected to the bottom of the upper die head, and a feed liquid runner is arranged between the upper die head and the lower die head. The feed liquid runner comprises a public part and a spiral part, the public part is connected to the axis end of the spiral part, and the far end of the spiral part is connected with a feeding runner extending out of the die head assembly. According to the multi-layer co-extrusion die head for the biodegradable mulching film, the flow of passing molten plastic materials can be controlled, so that the content of the molten plastic materials in finished products of degradable silver-black double-color mulching films, degradable mulching films and degradable black-white alternating mulching films can be controlled, meanwhile, a plurality of die head assemblies can be combined, and the production efficiency is improved. Therefore, the types of molten plastic materials are increased or reduced, and the effect of the multi-layer co-extrusion die head is achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of mulch film production equipment, and more specifically to a multi-layer co-extrusion die head for biodegradable mulch films. Background Art

[0002] Mulch films are widely used in agricultural planting. They are typically produced using blown film equipment. There are two main types of die heads for multi-layer co-extrusion blown film machines used to produce plastic films: the flat stacking die and the concentric sleeve die. These die heads can be stacking die heads, which feature multiple stacked annular discs with horizontal spiral flow channels defined at the interface between adjacent layers. Conventional plastic mulch films are non-degradable. With increasing usage and the passage of time, residual plastic mulch films accumulate in farmland, damaging the Earth's ecosystem, particularly the soil. Consequently, in recent years, research has explored the use of degradable mulch films, primarily made from PBAT and PPC, both renewable raw materials that are characterized by rapid degradation.

[0003] The raw materials of biodegradable mulch films now have other characteristics, such as sensitivity to temperature and very good fluidity. Therefore, when a superimposed multi-layer co-extrusion die is used to produce biodegradable silver-black two-color mulch films, degradable mulch films, and degradable black-and-white mulch films, the molten plastic material has very good fluidity, resulting in small flow resistance and fast flow speed of the molten plastic material in the horizontal spiral flow channel, which in turn leads to excessive proportion of a single molten material during the flow distribution process, thereby affecting the quality of the biodegradable silver-black two-color mulch films, degradable mulch films, and degradable black-and-white mulch films after production. At the same time, it is not convenient to control the flow rate of a single molten plastic material, which will affect the proportion of each molten plastic material component after production.

[0004] Chinese utility model patent application number CN220075520U discloses a stacked multi-layer co-extrusion blown film mold, which includes a die head, a mold column fixedly mounted at the lower end of the die head, a base fixedly mounted at the lower end of the mold column, a plurality of material disks disposed at the lower end of the die head near the outer side of the mold column, a feed port provided on one side of the material disk, a plurality of partition disks disposed between the material disks, a fixed disk fixedly mounted at the upper end of the material disk, a plurality of first threaded holes provided at the upper end of the fixed disk, a mold cover fixedly mounted at the upper end of the fixed disk near the outer side of the die head, a plurality of second threaded holes provided at the upper end of the mold cover, and the die head located inside the mold cover. Although this stacked multi-layer co-extrusion blown film mold has good fluidity for the material, it is unable to well control the fluidity of each molten plastic material when producing degradable silver-black two-color mulch film, degradable mulch film, and degradable black-and-white mulch film, resulting in an excessive proportion of a single or multiple materials, thereby affecting the quality of the mulch film after production.

[0005] Therefore, it is necessary to propose a multi-layer co-extrusion die head for biodegradable mulch to solve the above problems. Utility Model Content

[0006] (1) Technical problems solved

[0007] The purpose of the present invention is to solve the problems raised in the above background technology and to provide a multi-layer co-extrusion die head for a biodegradable ground film.

[0008] (2) Technical solution

[0009] In order to achieve the above-mentioned purpose, the present invention specifically adopts the following technical solutions:

[0010] A multi-layer co-extrusion die head for a biodegradable ground film comprises a plurality of die head assemblies, wherein the die head assembly comprises an upper die head and a lower die head fixedly connected to the bottom of the upper die head; a liquid flow channel is defined between the upper and lower die heads; the liquid flow channel comprises a common portion and a spiral portion; the common portion is connected to the axial end of the spiral portion; the distal end of the spiral portion is connected to a feed flow channel extending out of the die head assembly; a strip-shaped gap is defined on the spiral portion and extends into the common portion; the strip-shaped gap is larger near the axial end than at the distal end;

[0011] An annular cavity is formed inside the lower die head, a rotating baffle extending to the common portion is rotatably connected to the annular cavity, a worm gear is fixedly connected to the bottom of the outer wall of the rotating baffle, a rotating rod extending from the die head assembly is rotatably connected to the annular cavity, and one end of the rotating rod located in the annular cavity is fixedly connected to a worm connected to the worm gear;

[0012] A fixed baffle is fixedly connected at the axis of the upper die head and the lower die head, and the rotating baffle is rotatably connected to the fixed baffle. A circular hole is opened on the fixed baffle, and a special-shaped hole corresponding to the circular hole is opened on the rotating baffle. One end of the special-shaped hole is the same size as the circular hole, and the other end of the special-shaped hole is smaller than the circular hole.

[0013] Preferably, a fixed plate is provided on the top of the upper die head, a base is provided on the bottom of the lower die head, a boss is provided on the bottom of the lower die head and the fixed plate, a recess is provided on the top of the upper die head and the base to match the boss, and the fixed plate and the base are fixedly connected to multiple die head assemblies by bolts.

[0014] Preferably, a mold column is fixedly connected to the top of the base, a mixing cavity is provided between the mold column and the plurality of die head assemblies, and the mixing cavity is connected to the plurality of spiral portions via a through hole.

[0015] Preferably, the top of the fixed plate is fixedly connected to a rib, the top of the mold column is fixedly connected to a discharge head, an extrusion chamber is provided between the rib and the discharge head, the top of the extrusion chamber is larger than the bottom, the bottom of the extrusion chamber is connected to the mixing chamber, and the discharge head extends from the top of the extrusion chamber.

[0016] Preferably, a feed pipe connected to the feeding channel is fixedly connected to the outer wall of the die assembly, and one end of the rotating rod extending out of the die assembly is fixedly connected to a rotating handle, and the rotating rod is parallel to the feed pipe.

[0017] Compared with the prior art, the beneficial effects of the present invention are:

[0018] 1. Through the coordinated arrangement of the worm, worm wheel, fixed baffle and rotating baffle, the circular holes and special-shaped holes above can be staggered, thereby controlling the flow of the molten plastic material passing through, thereby achieving the control of the content of the molten plastic material in the finished products of the degradable silver-black two-color mulch film, degradable mulch film, and degradable black and white mulch film. At the same time, it can also reduce the flow of other molten plastic materials to increase the proportion of a certain molten plastic material, which is easy to control and adjust, and avoids the situation where too much of a certain molten plastic material causes a decrease in the quality of the finished product.

[0019] 2. Each die assembly is provided with a boss at the bottom and a concave at the top. By cooperating with the boss and the concave, multiple die assemblies can be combined to increase or decrease the types of molten plastic materials, thereby achieving the function of a multi-layer co-extrusion die. At the same time, the boss and the concave are set in polygonal shape, which can make multiple feed pipes located in a straight line or staggered, which is convenient for adjustment according to production conditions and has strong adaptability. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a three-dimensional schematic diagram of the structure of the utility model;

[0021] Figure 2 It is a three-dimensional cross-sectional schematic diagram of the structure of the utility model;

[0022] Figure 3 For this utility model Figure 2 Enlarged schematic diagram of area A in the middle;

[0023] Figure 4 This is a three-dimensional schematic diagram of the connection between the liquid flow channel and the feeding flow channel in the utility model;

[0024] Figure 5 This is a three-dimensional schematic diagram of the connection structure between the upper die head and the fixed plate in the utility model;

[0025] Figure 6 It is a three-dimensional cross-sectional schematic diagram of the connection structure between the lower die head and the annular cavity of the utility model;

[0026] Figure 7 It is a three-dimensional schematic diagram of the connection structure between the rotating baffle and the fixed baffle in the present invention;

[0027] Figure 8 This is a three-dimensional schematic diagram of the connection structure between the die head assembly and the base in the utility model;

[0028] Figure 9 It is a three-dimensional schematic diagram of the connection structure between the lower die head and the boss in the utility model.

[0029] Reference numerals:

[0030] 101. Die head assembly; 102. Upper die head; 103. Lower die head; 104. Liquid flow channel; 105. Common part; 106. Spiral part; 107. Feeding channel; 108. Strip gap; 109. Annular cavity; 110. Rotating baffle; 111. Worm gear; 112. Rotating rod; 113. Worm; 114. Fixed baffle; 115. Circular hole; 116. Special-shaped hole; 117. Fixed plate; 118. Base; 119. Boss; 120. Concave platform; 121. Mold column; 122. Mixing cavity; 123. Side rib; 124. Discharge head; 125. Extrusion cavity; 126. Feed pipe; 127. Rotating handle. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0032] See also Figure 1-9 A multi-layer co-extrusion die head for biodegradable ground film includes multiple die head components 101. The bottom of the die head component 101 is provided with a boss 119, and the top is provided with a concave platform 120. Through the cooperation of the concave platform 120 and the boss 119, multiple die head components 101 can be combined with each other. By increasing the number of die head components 101, it can be turned into a multi-layer co-extrusion die head. The boss 119 and the concave platform 120 are set as polygons, which can make multiple die head components 101 staggered, thereby The plurality of feed pipes 126 can be staggered or arranged in a straight line, which is convenient for the user to rotate and increases adaptability. The die assembly 101 includes an upper die 102 and a lower die 103 fixedly connected to the bottom of the upper die 102. The upper die 102 and the lower die 103 are sealed. The molten plastic material is added into the die assembly 101 from the feed pipe 126, passes through the feeding channel 107 and the spiral portion 106, and then converges in the common portion 105, and then passes through the circular hole 11 5 and the channel formed by the special-shaped hole 116 enter the mixing chamber 122, and a liquid flow channel 104 is opened between the upper die head 102 and the lower die head 103. The liquid flow channel 104 includes a common part 105 and a spiral part 106. The spiral part 106 is connected to both ends of the feeding flow channel 107, so that the molten plastic material is divided into two streams and finally converges at the common part 105. The common part 105 is connected to the axial end of the spiral part 106. The distal end of the spiral part 106 is connected to a nozzle extending from the die assembly 107. 1, a strip gap 108 is formed on the spiral portion 106 and extends into the common portion 105. The strip gap 108 is provided on the spiral portion 106 and penetrates the common portion 105. A portion of the molten plastic material gradually flows from the strip gap 108 in a centripetal horizontal direction, that is, flows radially toward the common portion 105. The closer to the strip gap 108, the greater the proportion of the molten plastic material flowing through. The size of the strip gap 108 near the axis is larger than that at the distal end.

[0033] refer to Figure 6 and Figure 7 An annular cavity 109 is provided inside the lower die head 103, and a rotating baffle 110 extending to the common part 105 is rotatably connected in the annular cavity 109. The top of the rotating baffle 110 is located in the common part 105, and the bottom is located in the annular cavity 109. The rotating baffle 110 is driven to rotate by the rotation of the worm gear 111. The bottom of the outer wall of the rotating baffle 110 is fixedly connected to the worm gear 111. A rotating rod 112 extending from the die head assembly 101 is rotatably connected in the annular cavity 109. The worm 113 is gear-connected with the worm gear 111, and the worm 113 is driven to rotate by the rotating rod 112, and finally the worm gear 111 is driven to rotate. One end of the rotating rod 112 located in the annular cavity 109 is fixedly connected to the worm 113 which is transmission-connected to the worm gear 111.

[0034] refer to Figure 7 , a fixed baffle 114 is fixedly connected to the axis of the upper die head 102 and the lower die head 103, and the rotating baffle 110 is rotatably connected to the fixed baffle 114, and the circular holes 115 on the fixed baffle 114 and the rotating baffle 110 cooperate with the fixed baffle 114. When the fixed baffle 114 and the circular hole 115 are staggered, the size of the formed hole will be reduced, thereby controlling the flow of molten plastic material. A circular hole 115 is opened on the fixed baffle 114, and a special-shaped hole 116 corresponding to the circular hole 115 is opened on the rotating baffle 110. The diameter of one end of the special-shaped hole 116 is the same as that of the circular hole 115, and the diameter of the other end is smaller than that of the circular hole 115. When the smaller end overlaps with the circular hole 115, the flow rate passing through will be reduced. The size of one end of the special-shaped hole 116 is consistent with the circular hole 115, and the size of the other end of the special-shaped hole 116 is smaller than the circular hole 115.

[0035] Specifically, refer to Figure 1 and Figure 2 A fixed plate 117 is provided at the top of the upper die head 102, and a base 118 is provided at the bottom of the lower die head 103. The fixed plate 117 and the base 118 fix the die head assembly 101 by bolts. A boss 119 is provided at the bottom of the lower die head 103 and the fixed plate 117, and a recess 120 that matches the boss 119 is provided at the top of the upper die head 102 and the base 118. The fixed plate 117 and the base 118 are fixedly connected to multiple die head assemblies 101 by bolts.

[0036] Specifically, refer to Figure 2 A mold column 121 is fixedly connected to the top of the base 118, and a mixing chamber 122 is provided between the mold column 121 and the multiple die head assemblies 101. The mixing chamber 122 is connected to the extrusion chamber 125 at the top. The molten plastic material mixed in the mixing chamber 122 will continue to move upward and become a film after passing through the extrusion chamber 125. The mixing chamber 122 is connected to the multiple spiral parts 106 through a through hole.

[0037] Specifically, refer to Figure 2 The top of the fixed plate 117 is fixedly connected with a rib 123, and the top of the mold column 121 is fixedly connected with a discharge head 124. The rib 123 cooperates with the discharge head 124 to form an extrusion cavity 125 that becomes smaller upward. An extrusion cavity 125 is provided between the rib 123 and the discharge head 124. The top of the extrusion cavity 125 is larger than the bottom. The bottom of the extrusion cavity 125 is connected to the mixing cavity 122, and the discharge head 124 extends from the top of the extrusion cavity 125.

[0038] Specifically, refer to Figure 1A feed pipe 126 connected to the feeding channel 107 is fixedly connected to the outer wall of the die assembly 101. The molten plastic material can be added into the die assembly 101 through the feed pipe 126. The rotating rod 112 extends out of the die assembly 101 and is fixedly connected to a rotating handle 127 at one end. The rotating rod 112 is parallel to the feed pipe 126.

[0039] In this embodiment, by connecting each different molten plastic material pipeline to a different feed pipe 126, after the molten plastic material enters the die assembly 101, the multiple molten plastic materials will be mixed in the mixing chamber 122, and then discharged and formed after passing through the extrusion chamber 125 between the rib 123 and the discharge head 124.

[0040] During operation, after the molten plastic material enters from the feed pipe 126, it is divided into two streams through the feeding flow channel 107 and passes through two identical spiral parts 106 respectively. The spiral part 106 is provided with a strip gap 108 that penetrates to the common part 105. A part of the molten plastic material gradually flows from the strip gap 108 along the centripetal horizontal direction, that is, it flows radially toward the common part 105, and the closer to the strip gap 108, the greater the proportion of the flow. Finally, the two streams of molten plastic material will converge in the common part 105, and then flow into the mixing chamber 122 after passing through the special-shaped holes 116 and the circular holes 115 on the rotating baffle 110 and the fixed baffle 114. When multiple streams of molten plastic material reach the annular vertical mixing chamber 122, the molten plastic material is evenly mixed in all directions of 360 degrees of the annular vertical total flow channel, and finally, after passing through the extrusion chamber 125, it is discharged from the retaining edge 123 and the discharge head 124.

[0041] When the proportion of a certain molten plastic material is too much, by rotating the rotating handle 127 on the corresponding die head assembly 101, the rotating handle 127 drives the worm 113 to rotate through the rotating rod 112, and the worm 113 rotates the worm wheel 111 through gear transmission, and the worm wheel 111 drives the top rotating baffle 110 to rotate, so that the circular holes 115 and the special-shaped holes 116 on the rotating baffle 110 and the fixed baffle 114 are staggered. One end of the special-shaped hole 116 is the same size as the circular hole 115, and the other side is smaller than the diameter of the circular hole 115. When the smaller end of the circular hole 115 is rotated to correspond to the special-shaped hole 116, the molten plastic material passing through will be reduced, thereby reducing the content of the molten plastic material in the degradable silver-black two-color mulch film, degradable mulch film, and degradable black and white mulch film moldings.

[0042] The above-mentioned embodiments are only preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and replacements made by technicians in this field on the basis of the present invention fall within the scope of protection required by the present invention.

Claims

1. A multi-layer co-extrusion die head for biodegradable mulch film, characterized by: The invention comprises a plurality of die head assemblies (101), wherein the die head assembly (101) comprises an upper die head (102) and a lower die head (103) fixedly connected to the bottom of the upper die head (102), a liquid flow channel (104) is provided between the upper die head (102) and the lower die head (103), the liquid flow channel (104) comprises a common portion (105) and a spiral portion (106), the common portion (105) is connected to the axial end of the spiral portion (106), the distal end of the spiral portion (106) is connected to a feeding flow channel (107) extending out of the die head assembly (101), the spiral portion (106) is provided with a strip gap (108) extending into the common portion (105), and the size of the strip gap (108) close to the axial end is larger than that of the distal end; An annular cavity (109) is provided inside the lower die head (103), a rotating baffle (110) extending to the common portion (105) is rotatably connected inside the annular cavity (109), a worm gear (111) is fixedly connected to the bottom of the outer wall of the rotating baffle (110), a rotating rod (112) extending from the die head assembly (101) is rotatably connected inside the annular cavity (109), and one end of the rotating rod (112) located inside the annular cavity (109) is fixedly connected to a worm (113) drivingly connected to the worm gear (111); A fixed baffle (114) is fixedly connected at the axis of the upper die head (102) and the lower die head (103); the rotating baffle (110) is rotatably connected to the fixed baffle (114); a circular hole (115) is provided on the fixed baffle (114); a special-shaped hole (116) corresponding to the circular hole (115) is provided on the rotating baffle (110); one end of the special-shaped hole (116) is the same size as the circular hole (115); and the other end of the special-shaped hole (116) is smaller than the circular hole (115).

2. The multi-layer co-extrusion die head for biodegradable mulch film according to claim 1, characterized in that: A fixing plate (117) is provided at the top of the upper die head (102), a base (118) is provided at the bottom of the lower die head (103), a boss (119) is provided at the bottom of the lower die head (103) and the fixing plate (117), a recess (120) matching with the boss (119) is provided at the top of the upper die head (102) and the base (118), and the fixing plate (117) and the base (118) are fixedly connected to a plurality of die head assemblies (101) by bolts.

3. The multi-layer co-extrusion die head for biodegradable mulch film according to claim 2, characterized in that: A mold column (121) is fixedly connected to the top of the base (118), a mixing chamber (122) is provided between the mold column (121) and the plurality of die head assemblies (101), and the mixing chamber (122) is connected to the plurality of spiral portions (106) via through holes.

4. The multi-layer co-extrusion die head for biodegradable mulch film according to claim 3, characterized in that: The top of the fixed plate (117) is fixedly connected to a rib (123), the top of the mold column (121) is fixedly connected to a discharge head (124), an extrusion chamber (125) is provided between the rib (123) and the discharge head (124), the top of the extrusion chamber (125) is larger than the bottom, the bottom of the extrusion chamber (125) is connected to the mixing chamber (122), and the discharge head (124) extends from the top of the extrusion chamber (125).

5. The multi-layer co-extrusion die head for biodegradable mulch film according to claim 1, characterized in that: A feed pipe (126) connected to the feed channel (107) is fixedly connected to the outer wall of the die head assembly (101); one end of the rotating rod (112) extending out of the die head assembly (101) is fixedly connected to a rotating handle (127); and the rotating rod (112) is parallel to the feed pipe (126).

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