Soft PVC floor production equipment and process

Abstract

This invention relates to the field of flooring production technology, specifically a production equipment and process for flexible PVC flooring. The production line includes sequentially arranged mixing, extrusion, thickness setting, embossing, cooling, and finishing zones. Two mixing units are arranged in parallel, and two extruders are staggered at an angle, resulting in a compact structure that can be operated by a single person. The molds and thickness setting rollers are equipped with dedicated structures and precise parameters to ensure the quality of the sheet forming. The equipment adopts a modular and detachable design, adaptable to three types of production processes: Process 1, without fiberglass structure, achieves dimensional self-balancing through thermal bonding of double-layer differentiated formula sheets; Process 2, with the addition of a fiberglass adhesive treatment system, uses immersion adhesive to effectively improve the bonding strength of the fiberglass; Process 3, equipped with a detachable online adhesive coating and distribution module, is suitable for the production of ultra-thin fiberglass felt. This invention's equipment has strong compatibility and can be adapted to the production of multiple LVT flooring types, resulting in excellent dimensional stability and structural bonding strength of the finished product.

Description

Technical Field

[0001] This invention relates to the field of flooring manufacturing technology, and in particular to a production equipment and process for soft PVC flooring. Background Technology

[0002] Existing technologies typically employ a two-step process: first, the bottom layer, middle layer, and foam layer are separately processed into sheets through internal mixing and calendering, then rolled, cooled, and stored; next, the rolls are transported to another composite lamination production line, where they are re-softened by heating rollers and heating channels, and then laminated layer by layer starting from the bottom. The sequence is as follows: mixing in a high-speed mixer + internal mixing + open mixing + sheet forming + cooling + winding and placement ---- transfer to another lamination line ---- large roller heating of the foam layer (self-priming function) for softening - large roller heating of the bottom layer (on the platform) + lamination of the foam layer with the bottom layer + heating channel + lamination with fiberglass mat via two rollers + heating channel - large roller heating of the middle layer + lamination of the middle layer with two rollers + heating channel - 400 small roller heating of the color film + lamination of the color film with two rollers + heating channel - 600 small roller heating of the wear-resistant layer + lamination of the wear-resistant layer with two rollers + cooling + slicing + UV coating + slitting and grooving (punching and trimming) + packaging. This process involves energy waste through "heating-cooling-reheating-single-piece production" and requires a large amount of transit and handling space and storage area for semi-finished products.

[0003] Current domestic technology also employs a "two-step method": First, the base material and intermediate material are processed into sheets through intensive mixing and calendering, then cut into segments, cooled, stored, and tempered. Next, the purchased color film, wear-resistant material, self-absorbing material, and fiberglass mesh pad are cut into sheets of equal length. Then, the different sheets are transferred to a dual-station press with both heating and cooling functions. Manual labor is required to place the sheets layer by layer (wear-resistant material + color film + intermediate material + fiberglass mesh + base material + self-absorbing pad) on the press using a textured template for prolonged heating and pressing. After 45 minutes, the sheets are cooled on another press. Once cooled, the semi-finished product is removed manually, UV coated, slit and grooved (punched and trimmed), and packaged. This process involves energy waste due to the "heating-cooling-reheating-single-sheet production-multiple manual labor" cycle, and requires significant transfer and handling space and storage area for semi-finished products.

[0004] A domestic company has recently developed an extrusion equipment manufacturer that produces this product. We only have patent applications and equipment listed, but no mature, qualified products have been produced. According to the patent description, aside from using two extruders and two sets of molds, the entire process principle and equipment structure are completely different from our newly filed patent. See the details in application number CN202211011297.2 and authorization announcement number CN115416250B. The equipment in this patent has two main extruders placed vertically, increasing the floor space. The molds are not in the same position, requiring two teams to operate. One set of thickness rollers is horizontal, and the other is vertical, affecting the observation of the sheeting. The intermediate material extruder is placed high up, far from the other, making it impossible for one person to observe the status of both extruders simultaneously, causing operational inconvenience. Because the intermediate material mold is vertically downward, mold adjustment and demolding are extremely difficult. During lamination, the base material is conveyed, while the intermediate material is freshly extruded, resulting in completely different stresses. This process laminates the base material and fiberglass simultaneously, which means that after lamination, there can be no further speed changes to ensure that the fiberglass does not stretch or wrinkle. This characteristic creates a contradiction between thickness control during embossing and the need to adjust the embossing roller speed according to different thickness dimensions. Producing qualified products is extremely difficult. In the bonding process, the base material is still bonded using a large roller. The large roller lacks resilience and, due to uneven thickness of the base material, will knead the fiberglass, causing twisting, pulling, and resulting in localized fiberglass breakage or wrinkling. Furthermore, there is no natural relaxation section after fiberglass bonding, leading to stress concentration.

[0005] The production process is completed in two steps. The first step, involving the internal mixer and calender, involves high-energy-consuming equipment that has been phased out by the government. This equipment is also highly polluting and requires a large area. It also requires a large workforce. The second step has two main problems: 1. While Korean production lines offer good continuity, they are difficult to operate. Domestically purchased Korean lines are largely inoperable. Crucially, Korean lines only provide the bonding technology for the equipment, not the bonding technology for the fiberglass mat and the interlayer material. 2. Domestic processes require each sheet to be cut into segments according to the flooring length specifications and enlarged approximately 30mm in size. From cutting, placing the sheets according to the structure, to extruding, each sheet requires manual operation. Although manufacturers attempt continuous production, they typically use multiple machines connected in a linear series, resulting in very long machines and extremely demanding factory requirements. The vertical placement of the two main extruders and the top-down die placement in existing extrusion patents result in larger widths and heights for the equipment, increasing the required space for the same number of machines.

[0006] The lamination line involves bonding three layers together. Due to tension fluctuations in the base and intermediate materials before lamination, and the simultaneous lamination of the base and intermediate materials in the extrusion line, there are also issues with different stress control between the base and intermediate materials. The fiberglass layer is highly prone to shifting or wrinkling between the two sheets, leading to decreased dimensional stability of the finished flooring and even quality problems such as exposed fiberglass. For double-layer structures (i.e., containing two LVT layers with different formulations or colors) with fiberglass sandwiched in between, one-time lamination can easily cause wrinkles and fiber breaks that go undetected. Even with simultaneous lamination, there are still issues with different stress levels at the top and bottom. Press forming involves manual placement. In China, fiberglass mesh is generally required for lamination; using fiberglass felt with a press process results in weak bonding. There is no information on using fiberglass felt or cloth during extrusion. Fiberglass mesh itself has directionality (no stretching along the fiber direction, but deformation occurs when stretched at an angle to the fiber direction). Uneven manual placement during introduction can also cause high internal stress after cooling, leading to warping. Summary of the Invention

[0007] In view of the problems existing in the prior art, the present invention is proposed.

[0008] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a soft PVC flooring production equipment, comprising a mixing unit, an extrusion unit, a thickness fixing zone, an embossing zone, a cooling zone, and a finishing zone connected in sequence; The mixing unit includes a first mixing unit and a second mixing unit, and the first mixing unit and the second mixing unit correspond to a first extruder and a second extruder, and the included angle between the first extruder and the second extruder is 20°~60°. The mixing unit includes an intermediate hopper, which is located between the first mixing unit and the first extruder, the second mixing unit and the second extruder; The extruder unit includes a connector and a die. The connector includes upper and lower sections, and the other end of each of the two connector sections is connected to the die. The connector connecting the first extruder consists of two vertically placed 90-degree elbows and a short sleeve that connects the extruder unit to the die. The connector connecting the second extruder consists of a horizontally placed 90-degree elbow plus a 120-degree elbow and a short sleeve that connects the extruder unit to the die.

[0009] In a preferred embodiment of the flexible PVC flooring production equipment of the present invention, the mold consists of two sets of sheet material molds arranged in parallel, with a distance of not less than 400mm between the two sets of molds. The mold is fixed on a mold trolley, and can move back and forth on the trolley without being fixed to the equipment, and can also be adjusted up and down.

[0010] As a preferred embodiment of the soft PVC flooring production equipment of the present invention, the thickness fixing zone includes rollers 1, 2, 3, and 4 arranged sequentially from bottom to top, divided into two groups. Rollers 3 and 4 form the upper group to fix the thickness of the intermediate material sheet extruded by the first extruder through the upper die; rollers 1 and 2 form the lower group to fix the thickness of the bottom material sheet extruded by the second extruder through the lower die.

[0011] As a preferred embodiment of the soft PVC flooring production equipment of the present invention, the embossing area includes a bonding roller, a main bonding roller, an embossing bonding roller, and a heating lamp disposed between the main bonding roller and the embossing bonding roller. The embossing and bonding roller is followed by a cooling zone, and the finishing zone includes a traction machine, a shearing machine, and a stacking machine.

[0012] As a preferred embodiment of the soft PVC flooring production equipment of the present invention, a glass fiber processing system is provided below the first extruder, including a glass fiber unwinding device and a glass fiber coating device. The processed glass fiber is sent to the glass fiber bonding roller at the outlet of the lower set of thickness rollers to be laminated with the base material.

[0013] In a preferred embodiment of the soft PVC flooring production equipment of the present invention, the first extruder is connected to the mold and the embossing area, the embossing area including a plurality of rubber rollers; the second extruder is connected to the mold and the conveyor belt, and the upper end of the conveyor belt is provided with a support roller; A conveying device is provided between the embossing area and the cooling area. The conveying device is provided with bonding rollers at both ends and a pressing and unwinding trolley is provided at the lower end of the conveying device. The cooling zone employs a staggered roller cooling system.

[0014] As a preferred embodiment of the soft PVC flooring production equipment of the present invention, a glue applicator and a uniform distribution machine are provided between the conveyor belt and the embossing area, a conveying device is provided at the end of both the conveyor belt and the embossing area, and a heating lamp is provided between the two conveying devices.

[0015] Beneficial effect: The production line of this invention adopts the method of disassembling and assembling some parts of the production line to realize multiple floor processes.

[0016] In view of the process of soft PVC flooring production equipment, the following solutions are proposed: To solve the above-mentioned technical problems, the present invention provides the following technical solution: a process using soft PVC flooring production equipment, comprising, Step 1: Raw material plasticization - The first extruder and the second extruder respectively input the mixture of different formulations, and the material reaches a fluid plasticized state through heating and shearing. Step 2: Die extrusion – The first extruder extrudes the intermediate sheet material through a connected die, and the second extruder extrudes the bottom sheet material through a connection with the lower die. Step 3: Double-layer synchronous calendering and thickness setting—the intermediate material sheet is calendered by the upper set of pressure rollers in the vertical thickness setting zone, and the bottom material sheet is calendered by the lower set of pressure rollers in the thickness setting zone; Step 4: Online pretreatment and embedding of fiberglass - After the fiberglass treatment system is unwound and tension is adjusted, the surface is treated with adhesive by the fiberglass coating device to prepare for subsequent bonding with the base material; Step 5: Composite of intermediate and base materials separately - The intermediate material is laminated with color film and wear-resistant layer on the laminating roller and embossed by the embossing roller and laminating roller. The glass fiber and base material are laminated at the glass fiber laminating roller at the outlet of the lower set of thickness rollers. After the upper intermediate material and base material have completed stress release, the required bonding surface is instantly heated to perform secondary bonding of the upper and lower parts to form an LVT substrate. Step 6: Gradient cooling and shaping – The LVT substrate is gradually cooled through subsequent cooling zones.

[0017] As a preferred embodiment of the process of the soft PVC flooring production equipment of the present invention, in step 5, after the medium material is laminated with the film, it is conveyed on the horizontal roller and kept warm for more than 10 seconds to perform controlled free stress release and make the stress balanced. After the fiberglass is bonded to the base material, it undergoes free stress release on the conveyor belt, eliminating the rubbing and wrinkling stress during fiberglass bonding. After the surface to be bonded is heated instantly, the middle material with the film embossed is bonded to the base material with the fiberglass already bonded. In step 6, the substrate is kept in a tensioned and controllable state in the cooling travel section. The length of the unconstrained section roller does not exceed 2 meters. The height of the top of the roller above the constraint point is controlled to be more than 1 / 50 of the roller length. When the distance between adjacent lower rollers is greater than 0.4 meters, a rubber roller constraint is applied to the upper middle part. After natural cooling, it enters the cooling zone.

[0018] As a preferred embodiment of the process of the soft PVC flooring production equipment described in this invention, the speed control unit from the bonding roller onwards adopts a servo control system, and the error between the displayed linear speed and the actual speed does not exceed one-thousandth. The direction of the material after the fiberglass is bonded to the base material is always in a state of turning and being under stress, and there is no free and uncontrolled form; The cutting process uses a blade-type chipless cutting machine to reduce the amount of debris and fiberglass fluff generated during punching.

[0019] The beneficial effects of this invention are as follows: This invention adopts a step-by-step composite process with intermediate and base materials. The intermediate material is first laminated and embossed, and the base material is first laminated with fiberglass. After the stress of each material is released, a second composite process is performed. This ensures that only a single layer of the base material is involved when the fiberglass is laminated, resulting in smaller wall thickness errors and less chance of rubbing. During the second composite process, the fiberglass is already supported by the base material layer, significantly reducing rubbing and wrinkles. This process eliminates the mixing, cooling, winding, and reheating steps in the traditional "two-step method," achieving direct online composite molding from raw materials to a three-layer preform. The energy consumption per unit product is reduced by approximately 25% to 30%, the production line floor space is reduced by approximately 25%, and the yield rate is significantly improved. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a simplified schematic diagram of the production line required for process one in this invention; Figure 2 This is a simplified schematic diagram of the production line required for process two in this invention; Figure 3 This is a simplified schematic diagram of the production line required for process three in this invention. Detailed Implementation

[0022] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0023] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0024] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0025] Example 1 This is the first embodiment of the present invention, which provides a flexible PVC flooring production equipment.

[0026] Specifically, such as Figure 1As shown, the equipment along the production line from left to right includes mixing unit 1, extrusion unit 2, thickness fixing zone 3, embossing zone 4, cooling zone 5, and finishing zone 6.

[0027] The mixing unit 1 includes a first mixing unit 11 and a second mixing unit 12, which are placed in parallel. Each mixing unit includes an intermediate hopper 13, which is connected to a screw feeder for feeding material into the extruder hopper. The mixing unit 1 and the extruder unit 2 are connected together for feeding according to the same last digit of their serial numbers; that is, the first mixing unit 11 feeds the first extruder 21, and the second mixing unit 12 feeds the second extruder 22.

[0028] Extrusion unit 2 includes a first extruder 21 and a second extruder 22, arranged vertically and staggered horizontally. The first extruder 21 is placed on a platform, with sufficient space underneath for the fiberglass unwinding structure and coating device required for processes two and three. The second extruder 22 is placed on the ground, with its center height less than 800mm. The platform where the first extruder 21 is located has a height of 1250mm~1650mm, and the center height of the upper die 24 connected to the first extruder 21 is between 1450mm~1550mm. The centerlines of the first extruder 21 and the second extruder 22 form an angle of 20°~60°. This angled arrangement ensures that the two feeders are no more than 2.5 meters apart, with a distance error of no more than 1 meter along the main centerline, allowing operation by one set of personnel from a normal LVT production line. Each extruder includes a frame, drive motor, integral reducer + distribution box, barrel, hopper, feeder, and hopper mounting base. The drive motor, reducer, distribution box, and barrel are sequentially mounted on the frame. The hopper mounting base is mounted on the feeder, which is mounted on the distribution box and connected via a rotating shaft. The extruder's reducer is a dedicated reducer, with its input shaft located above the first set of intermediate shafts. The frame is a single-beam structure with a center height not exceeding 800mm.

[0029] The connecting body 23 comprises two sets. The first set of connecting bodies 23 connects the first extruder 21 to the upper die 24 via two vertically placed 90° elbows and short sleeves, with the material flow direction being first right-down and then right. The second set of connecting bodies 23 connects the second extruder 22 to the lower die 24 via a horizontally placed 90° elbow, a horizontally placed 120° elbow, and short sleeves. This elbow combination design ensures that the hoppers of both extruder units are in an unobstructed state, facilitating feeding of the hoppers by the screw conveyor. The material level gauge in the hopper controls the start and stop of feeding.

[0030] Mold 24 consists of two sets of sheet metal molds arranged parallel to each other, with a distance of at least 400mm between them. Mold 24 is fixed to a mold trolley and can move back and forth and adjust up and down on the mold trolley 16 after the elbow is removed. A flat support plate with a width equivalent to that of the upper mold 24 is located below it. L-shaped support plates are located on both sides of the lower mold plates of both the upper and lower molds 24. Linear bearings are located below the L-shaped support plates, and the guide rails of the linear bearings are fixed to the mold trolley and arranged parallel to the centerline. A guide rail groove is located below the support plate of the upper mold 24, allowing the flat support plate to move back and forth within the groove. A steering roller is located below the flat support plate and above the lower mold 24. A 300mm high pedal is included on the side of the mold trolley.

[0031] Thickness stabilization zone 3 includes rollers 1, 2, 3, and 4 arranged sequentially from bottom to top, divided into upper and lower groups. Rollers 3 and 4 form the upper group, which sizing the thickness of the intermediate sheet extruded by the first extruder 21 through the upper die 24; rollers 1 and 2 form the lower group, which sizing the thickness of the bottom sheet extruded by the second extruder 22 through the lower die 24. All thickness stabilization rollers are heavy-duty rollers with a wall thickness greater than 30mm, integrally quenched, and with a surface hardness greater than HRC50. The diameter of the upper group thickness stabilization rollers is not less than 380mm, and its upper roller has a medium-to-high margin of 0.1mm. The upper roller of the lower group thickness stabilization rollers has a diameter of 300mm, a medium-to-high margin of 0.1~0.2mm, and a lower roller diameter of not less than 380mm. The thickness adjustment lifting mechanism of the upper group thickness stabilization rollers is located at the top, and the lifting mechanism of the lower group thickness stabilization rollers is located at the bottom. The lower roller of the lower group thickness stabilization rollers adjusts its clearance by lifting along a guide rail groove inclined at approximately 45° from the lower left to the upper right. All four rollers are temperature-controlled by an oil temperature controller. Thickness zone 3 also includes two sets of lifting mechanisms, which control the gap between the upper and lower sets of rollers respectively. The distance between the lower roller of the upper thickness-fixing roller and the upper roller of the lower thickness-fixing roller is not less than 100mm.

[0032] In process mode one, the intermediate and base materials after thickness determination are fed to the right onto the vertically placed substrate bonding roller 41 for bonding. Two sets of rubber rollers 45 are positioned between the substrate bonding roller 41 and the thickness determination zone 3 to ensure the overall tension of the substrate. Meanwhile, a main bonding roller 42 and an embossing bonding roller 43 are located in the embossing zone 4. The main bonding roller 42 is positioned between the embossing bonding roller 43 and the bonding roller 41. A heating lamp 44 is installed between the main bonding roller 42 and the bonding roller 41 to keep the sheet warm, ensuring the sheet is hot during bonding. The rubber rollers 45 above the bonding roller 41 are temperature-controlled by an oil temperature controller and include a lifting mechanism to control the gap. The main bonding roller 42 is a steel roller with two cylinder-controlled rubber rollers 45 mounted on it. Two sets of rubber rollers 45 are positioned directly above the main bonding roller 42. Their upper surfaces are above half the diameter of the main bonding roller 42 and above 1 / 5 to 1 / 2 the diameter of the embossing bonding roller 43. The embossing bonding roller 43 consists of two rollers: a rubber roller closer to the main bonding roller 42 and a texture roller. The center line connecting the rubber roller and the texture roller forms an upward angle of 10° to 45°. The rubber roller 45 is close to the main bonding roller 42, while the texture roller is farther away.

[0033] Process 1 features the simplest equipment structure, with no fiberglass processing system located beneath the platform. It retains only the functions of double-layer extrusion, thickness determination, substrate bonding, film bonding, and embossing. This method is suitable for producing fiberglass-free double-layer self-balancing LVT flooring, achieving dimensional self-balancing through the direct bonding of two LVT layers with different formulations or colors.

[0034] Example 2 describes the equipment structure of the production equipment of the present invention in process mode two, used to produce double-layer self-balancing LVT flooring with pre-coated fiberglass in the middle. Figure 2 As shown, in Process 2, based on Example 1, a fiberglass processing system 7 is added below the platform, and a sheet conveyor belt 8 is added.

[0035] The fiberglass processing system, located below the platform, includes a fiberglass unwinding device, a fiberglass adhesive coating device, and a fiberglass self-balancing mechanism. The unwinding device, installed below the platform, is used to hold rolls of fiberglass cloth, felt, or mesh and provides unwinding functionality. A tension adjustment device ensures the fiberglass material is fed out with constant tension during unwinding. The adhesive coating device uses horizontally positioned first and second coating rollers. The gap between the two rollers is finely adjusted via a screw, with an adjustment range of 0.3~0.8mm. Adhesive is placed between the first and second coating rollers, and baffles are installed on both sides of the rollers to prevent adhesive leakage. The fiberglass material is fully immersed in the adhesive solution from top to bottom, directly above the center of the first and second coating rollers, and then fed out from the bottom, winding half a turn around one of the rollers before passing through a thickness-fixing zone 3 and turning. This horizontal immersion adhesive coating method allows the adhesive to penetrate the internal fiber network of the fiberglass felt, rather than merely adhering to the surface, fundamentally improving the bonding strength. After being uniformly coated with adhesive, the fiberglass enters a far-infrared coagulation section to solidify the adhesive. Far-infrared heating rapidly and evenly cures the adhesive, preventing it from flowing or failing to penetrate during subsequent bonding. A fiberglass self-balancing mechanism further adjusts the fiberglass tension after coating, eliminating uneven tension generated during unwinding and coating, ensuring the fiberglass enters the subsequent bonding station in a flat state. The treated fiberglass is then fed to the bonding roller 41 at the exit of the next set of thickness rollers to be laminated with the base material.

[0036] In process mode two, in the lower set of thickness-fixing rollers in thickness-fixing zone 3, roller one has a larger diameter than roller two. Two sets of cylinder-controlled rubber rollers 45 are located near the thickness-fixing exit edge and the center line of roller one. A small-diameter deflector roller is located on each side of the upper plane of roller two, with the upper plane of the deflector rollers being at least 30 mm higher than the upper plane of roller two. The fiberglass is thus deflected and enters the two sets of cylinder-controlled rubber rollers 45 on the right side of roller one for bonding with the pressing area of ​​roller two. After the base material is bonded with fiberglass, it is conveyed to the conveyor belt 8 located directly below the main bonding roller 42 and the embossing bonding roller 43.

[0037] The conveyor belt 8 is located directly below the main bonding roller and the embossing bonding roller 43, and is used to receive the fiberglass-coated base material and transport it to the right. A rubber roller 45 is positioned above the conveyor belt 8, and is located at the lower right of the embossing bonding roller 43 and the upper right of the conveyor belt 8, flush with the conveyor belt 8. A heating lamp 44 is located above the conveyor belt 8 and below the rubber roller 45. A bonding roller 41 is connected behind the embossing bonding roller 43. The bonding roller 41 has two cylinder-controlled rubber rollers 45, used to press the bonding intermediate material and the base material together. At this point, the intermediate material has already been coated with film and embossed, and the base material has been coated with fiberglass. The task of the bonding roller 41 is to bond the coated and embossed intermediate material and the fiberglass-coated base material together. A conveyor device 81 is connected to the right side of the bonding roller 41. An unwinding trolley 82 is located below the conveyor device 81, and a heating lamp 44 is located above the conveyor device 81.

[0038] Two cylinder-controlled rubber rollers 45 are provided on the left side of the conveyor to press the lower film released by the unwinding trolley 82 and enhance the bonding strength between the middle and bottom materials. Similarly, two cylinder-controlled rubber rollers 45 and bonding rollers 41 are provided on the right side of the conveyor to ensure the stability of the sheet material during transportation.

[0039] The cooling and forming zone includes multiple rollers, allowing the sheet material to be pulled in an S-shaped staggered manner, increasing the cooling contact area and reducing transport time. This effectively reduces the sheet material temperature and ensures stable shaping. After cooling, the sheet material is fed into the cutting station by a traction device, where a high-precision cutting blade precisely cuts it to the preset dimensions.

[0040] Example 3 illustrates the equipment structure of the production equipment of the present invention under three process modes, specifically targeting the subdivided processes of ultra-thin fiberglass mat. For example... Figure 3 As shown, in process three, a fiberglass unwinding device and a fiberglass self-balancing mechanism are installed below the platform. However, the fiberglass does not pass through the fiberglass adhesive coating device; the uncoated fiberglass is directly fed to the bonding roller 41 after the thickness is fixed by rollers one and two. At the bonding roller 41, a steel roller is installed above the bonding roller 41, and a heating lamp 44 is installed on the upper left of the steel roller to heat the surface of the substrate. The function of the heating lamp 44 is to heat the surface of the substrate before the fiberglass is pressed with the substrate, so that the surface of the substrate is in a hot softening state, which enhances the mechanical bonding force between the uncoated fiberglass and the substrate. After the substrate is bonded with the uncoated fiberglass, it is conveyed onto the conveyor belt 8. Between the beginning of the conveyor belt 8 and the lower left of the main bonding roller 42, an online adhesive coating machine A is installed to coat the surface of the ultra-thin fiberglass felt that has been bonded to the substrate with adhesive. To the right of the adhesive coating machine A, a uniform distributor B is installed to distribute the coated adhesive evenly on the surface of the fiberglass felt.

[0041] To ensure that all three processes are simultaneously satisfied, Process 3 is designed as a detachable module, based on the combined configuration of Processes 1 and 2. Specifically, based on Process 2, the distance between the main bonding roller 42 and subsequent components and the thickness-fixing zone 3 is increased to create installation space for the online glue applicator A and the equalizer B. Additionally, a rubber roller 45 and a bonding roller 41 for the intermediate base material are added, and a support roller is added to the right side of the conveyor belt 8 to facilitate the transport of the intermediate base material. To allow for the installation of the plug-and-play online glue applicator A and the equalizer B, the entire upper section containing the main bonding roller 42 and the embossing zone 4 needs to be moved upwards by at least 300mm. The online glue applicator A and the equalizer B are detachable modules; they are added during the production of Process 3 and removed when no longer needed to restore the Process 1 and 2 mode.

[0042] Example 4 is the fourth embodiment of the present invention, wherein step 1 is raw material preparation and mixing. PVC resin, calcium powder, DOTP plasticizer, lubricant, stabilizer, and other raw materials are weighed and prepared according to the intermediate material formula and the base material formula, respectively. The intermediate material formula focuses on dimensional stability and hardness, while the base material formula focuses on toughness and bending resistance. The intermediate material formula raw materials are fed into the first mixing unit 11, and the base material formula raw materials are fed into the second mixing unit 12. The mixed materials are then stored in their respective intermediate silos 13.

[0043] Step 2 involves raw material plasticization and extrusion. A screw feeder connected to the intermediate hopper 13 delivers the mixture into the hoppers of the first extruder 21 and the second extruder 22, respectively. Level gauges in the hoppers control the start and stop of feeding to ensure stable material levels. The first extruder 21 receives the intermediate feed mixture, and the second extruder 22 receives the bottom feed mixture. Within the extruders, the materials undergo heating and shearing forces, melting, shearing, and mixing to reach a fluid state and exhibit good plasticity.

[0044] Step 3 is die extrusion molding. The plasticized material is fed into die 24 through the extruder. The material from the first extruder 21 is extruded as a sheet material through the upper die 24, which is connected by two vertically placed 90° elbows and a short sleeve. The material from the second extruder 22 is extruded as a sheet material through the lower die 24, which is connected by a 90° elbow, a 120° elbow, and a short sleeve. The two sets of dies are arranged in parallel, producing LVT substrates of different materials and thicknesses simultaneously.

[0045] Step 4 is the double-layer synchronous calendering thickness setting. The extruded sheet enters thickness setting zone 3 for thickness setting. The intermediate sheet is set by the upper set of thickness setting rollers, namely rollers three and four. The diameter of the upper set of thickness setting rollers is not less than 380mm, and the height of the upper roller is 0.1mm. The temperature is controlled by an oil temperature controller. The bottom sheet is set by the lower set of thickness setting rollers, namely rollers one and two. Roller one has a diameter of 300mm and a height of 0.1~0.2mm, while roller two has a diameter of not less than 380mm. The gap between the upper and lower sets of rollers is adjusted by a lifting mechanism to control the sheet thickness. The lower roller of the lower set of thickness setting rollers is raised and lowered along a 45° inclined guide rail groove to adjust the gap.

[0046] Step 5 involves double-layer substrate bonding. The intermediate and base materials, after thickness determination, are fed to the right onto the vertically positioned substrate bonding roller 41 for bonding. Two sets of rubber rollers 45 are positioned between the bonding roller 41 and the thickness determination zone 3, with a heating lamp 44 between them to keep the sheet warm and ensure it remains hot during bonding. One roller on the substrate bonding roller 41 is a rubber roller, with its temperature controlled by an oil temperature controller and the gap controlled by a lifting mechanism. The intermediate and base materials are pressed together by the bonding roller assembly 41 while hot, forming a double-layer LVT substrate.

[0047] Step 6 involves film lamination and embossing. The double-layer LVT substrate passes through lamination roller group 41 and then enters the main lamination roller 42. The main lamination roller 42 is a steel roller with two small rubber rollers controlled by cylinders, which laminate the color film and wear-resistant layer onto the upper surface of the substrate. The laminated substrate then enters the embossing lamination roller 43.

[0048] Step 7 is post-processing. The embossed substrate undergoes a UV coating production line for surface abrasion protection. Then, it is segmented and grooved using a grooving machine or by punching and beveling. Finally, the finished product is packaged. Process 1 is the production process for fiberglass-free double-layer self-balancing LVT flooring, with the simplest flow. It achieves dimensional self-balancing by directly heat-bonding two layers of LVT with different formulations, utilizing the difference in shrinkage rates between the two layers. Good dimensional stability can be achieved without fiberglass reinforcement. It is suitable for the production of conventional double-layer LVT flooring with moderate dimensional stability requirements.

[0049] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A soft PVC floor production apparatus, characterized in that: include, The mixing unit (1), extruder (2), thickness control zone (3), embossing zone (4), cooling zone (5), and finishing zone (6) are connected in sequence. The mixing unit (1) includes a first mixing unit (11) and a second mixing unit (12), and the first mixing unit (11) and the second mixing unit (12) correspond to the first extruder (21) and the second extruder (22), and the included angle between the first extruder (21) and the second extruder (22) is 20°~60°; The mixing unit (1) includes an intermediate hopper (13) located between the first mixing unit (11) and the first extruder (21), the second mixing unit (12) and the second extruder (22); The extruder unit (2) includes a connector (23) and a mold (24). The connector (23) includes two sets, upper and lower, and the other end of each set of connectors (23) is connected to the mold (24). The connector (23) connecting the first extruder (21) consists of two vertically placed 90-degree elbows and a short sleeve that connects the first extruder (21) to the mold (24). The connector connecting the second extruder (22) consists of a horizontally placed 90-degree elbow plus a 120-degree elbow and a short sleeve that connects the second extruder unit (22) to the mold (24).

2. The soft PVC floor production equipment according to claim 1, characterized in that: The mold (24) consists of two sets of sheet metal molds arranged in parallel, with a distance of not less than 400mm between the two sets of molds (24); the mold (24) is fixed on the mold trolley, and the mold (24) can move back and forth on the trolley when not fixed to the equipment, and can also be adjusted up and down.

3. The soft PVC floor production equipment according to claim 2, characterized in that: The thickness-fixing zone (3) includes rollers 1, 2, 3 and 4 arranged from bottom to top, divided into two groups. Rollers 3 and 4 form the upper group to fix the thickness of the intermediate sheet extruded by the first extruder (21) through the upper die (24); rollers 1 and 2 form the lower group to fix the thickness of the bottom sheet extruded by the second extruder (22) through the lower die.

4. The soft PVC floor production equipment according to claim 2, characterized in that: The embossing area (4) includes a bonding roller (41), a main bonding roller (42), an embossing bonding roller (43), and a heating lamp (44) disposed between the main bonding roller (42) and the embossing bonding roller (43). The embossing and bonding roller (43) is followed by the cooling zone (5), and the finishing zone (6) includes a traction machine (61), a shearing machine (62), and a stacking machine (63).

5. The soft PVC floor production equipment according to claim 4, characterized in that: A glass fiber processing system (7) is provided below the first extruder (21), including a glass fiber unwinding device and a glass fiber coating device. The processed glass fiber is sent to the glass fiber bonding roller at the outlet of the lower set of thickness rollers to be laminated with the base material.

6. The soft PVC floor production apparatus of claim 5, wherein: The first extruder (21) is connected to the die (24) and the embossing area (4), which includes a plurality of rubber rollers (45); the second extruder (22) is connected to the die (24) and the conveyor belt (8), and the upper end of the conveyor belt (8) is provided with a support roller; A conveying device (81) is provided between the embossing area (4) and the cooling area (5). The conveying device (81) has bonding rollers (41) at both ends and a pressing and unwinding trolley (82) at the lower end of the conveying device (81). The cooling zone (5) adopts a staggered roller cooling method.

7. The soft PVC floor production apparatus of claim 6, wherein: A glue applicator (A) and a uniform distributor (B) are provided between the conveyor belt (8) and the embossed area (4). A conveying device (81) is provided at the end of both the conveyor belt (8) and the embossed area (4). A heating lamp (44) is provided between the two conveying devices (81).

8. A process for producing soft PVC floorings using the apparatus of claim 3, characterized in that, Includes the following steps: Step 1: Raw material plasticization - The first extruder (21) and the second extruder (22) respectively input the mixture of different formulations, and the material reaches the fluid plasticization state through heating and shearing. Step 2: Die extrusion - The first extruder (21) extrudes the intermediate sheet through the connecting die (24), and the second extruder (22) extrudes the bottom sheet through the connection with the lower die (24); Step 3: Double-layer synchronous calendering and thickness determination - the intermediate material sheet is calendered by the upper set of pressure rollers in the vertical thickness determination zone (3), and the bottom material sheet is calendered by the lower set of pressure rollers in the thickness determination zone (3). Step 4: Online pretreatment and embedding of fiberglass - After the fiberglass treatment system (7) is unwound and tension is adjusted, the surface is treated with fiberglass adhesive by the fiberglass adhesive coating device to prepare for subsequent bonding with the base material; Step 5: Composite of intermediate and base materials respectively - The intermediate material is laminated with color film and wear-resistant layer on bonding roller (41) and embossed by bonding roller (43). The glass fiber and base material are laminated at glass fiber bonding roller (41) at the outlet of the lower set thickness roller. After the upper intermediate material and base material have completed stress release, the required bonding surface is heated instantly to perform secondary bonding of the upper and lower parts to form LVT substrate. Step 6: Gradient cooling and shaping - The LVT substrate is gradually cooled through the subsequent cooling zone (5). 9.The process for the soft PVC floor production device of claim 8, wherein: In step 5, after the medium material is laminated into the film, it is conveyed on a horizontal roller and kept warm for more than 10 seconds to release controlled free stress and make the stress even. After the glass fiber is bonded to the base material, it undergoes free stress release on the conveyor belt (8) to eliminate the rubbing and wrinkling stress during the bonding of the glass fiber. After the surface to be bonded is heated instantly, the middle material with the film embossed is bonded to the base material with the fiberglass already bonded. In step 6, the substrate is kept in a tensioned and controllable state in the cooling travel section. The length of the unconstrained section roller does not exceed 2 meters. The height of the top of the roller above the constraint point is controlled to be more than 1 / 50 of the roller length. When the adjacent spacing of the lower roller is greater than 0.4 meters, a rubber roller (45) is applied to the upper middle part for constraint. After natural cooling, it enters the cooling zone (5).

10. The process for the production of soft PVC flooring equipment as claimed in claim 9, wherein: The speed control units starting from the bonding roller (41) all adopt a servo control system, and the error between the displayed linear speed and the actual speed does not exceed one-thousandth; The direction of the material after the fiberglass is bonded to the base material is always in a state of turning and being under stress, and there is no free and uncontrolled form; The cutting process uses a blade-type chipless cutting machine to reduce the amount of debris and fiberglass fluff generated during punching.

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