Double-layer pet bottle preform with high barrier property, production equipment and process

Abstract

The application belongs to the technical field of packaging bottle materials and forming, and particularly relates to a double-layer PET bottle blank with high barrier property, a production device and a process. The double-layer PET bottle blank comprises an outer layer comprising basic PET resin and an inner layer comprising a PET composite material containing 5-15 wt% of surface silane modified nano montmorillonite. The inner layer and the outer layer are integrally formed by co-injection molding, and a gradient transition zone with a thickness of 0.05-0.2 mm is formed at the interface of the two layers. The two-phase melt in the gradient transition zone realizes molecular chain entanglement. First, surface silane modified nano montmorillonite is selected, and the interface bonding force between the nano lamella and PET is enhanced through a silane coupling agent. By designing a gradient transition zone structure (thickness of 0.05-0.2 mm), molecular chain mutual diffusion and entanglement are induced by using a melt temperature difference (Delta T=5+ / -0.5 DEG C), the interface peeling strength is increased to >=5 N / mm, and the inner layer peeling state dispersion structure (interlayer spacing >=2 nm) is also limited, so that the oxygen diffusion path is extended by about three times.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of packaging bottle materials and forming, and particularly relates to a double-layer PET bottle blank with high barrier performance, a production device and a process. BACKGROUND

[0002] PET (polyethylene terephthalate) is a widely used thermoplastic polyester material. PET bottles are widely used in the packaging of carbonated beverages, fruit juice, mineral water and other beverages due to their lightness, transparency, impact resistance and easy recyclability. PET bottles are obtained by blow molding of bottle blanks. At present, various multi-layer PET bottle blanks appear. One is to use EVOH as a barrier layer. However, EVOH has poor compatibility with PET, is prone to delamination and is not resistant to acidic environment, and is not easy to be applied to carbonated beverage bottles and craft beer bottles. The other also uses nano-montmorillonite as a barrier layer, but uneven dispersion will lead to insufficient barrier efficiency (OTR>0.001 cc / bottle·day). At the same time, the above-mentioned multi-layer structure bottle blank mostly uses traditional co-injection molding process to cause clear interface and weak interlayer bonding force (interface glass strength≤2 N / mm). Therefore, the barrier ability, layer bonding force and impact resistance of the existing multi-layer PET packaging need to be further improved.

[0003] Therefore, the present application is proposed. SUMMARY

[0004] The first object of the present application is to effectively solve the problems of insufficient barrier ability, interlayer bonding force and impact resistance of the existing multi-layer PET bottle blank. The present application is completed by optimizing PET material, structure and process.

[0005] The second object of the present application is to effectively solve the problem that the existing PET bottle blank requires strict requirements for impurities during production. Since the traditional filter needs to be removed after blocking to replace and clean, the whole production line needs to be shut down. The present application is completed by the process steps of filtering from inside to outside, cooperating with rotary filtering mode, then side-out shunting, rectifying and extrusion molding to complete online filtering.

[0006] In order to solve the above technical problems, the inventors have summarized the technical solutions of the present application through practice. The present application adopts the following technical solutions:

[0007] A double-layer PET bottle blank with high barrier performance comprises:

[0008] an outer layer comprising a basic PET resin;

[0009] an inner layer comprising a PET composite material containing 5-15 wt% of surface silane modified nano-montmorillonite;

[0010] The inner layer and the outer layer are integrally formed by co-injection molding, and a gradient transition zone with a thickness of 0.05-0.2 mm is formed at the interface between the two layers, and molecular chain entanglement is achieved in the gradient transition zone.

[0011] In a more preferred solution, the thickness of the inner layer accounts for 15-25% of the total wall thickness of the preform, and the thickness of the outer layer accounts for 75-85%.

[0012] The particle size of the surface silane-modified nano-montmorillonite is 20-80 nm, the interlayer spacing is ≥2.5 nm, and the surface silane-modified nano-montmorillonite is dispersed in the PET matrix in an exfoliated state.

[0013] In a more preferred solution, the surface silane-modified nano-montmorillonite is prepared by the following process: montmorillonite:silane = 1:0.3-0.5 by mass ratio, reaction in an ethanol / water solution with a volume ratio of 8:2 at pH = 4.0, stirring at 60°C for 6 hours.

[0014] In a more preferred solution, the process steps are as follows:

[0015] Step 1, raw material treatment

[0016] The raw materials of the base PET resin are dried at 165±5°C for 5 hours;

[0017] The raw materials of the PET composite are dried at 130±10°C for 4 hours;

[0018] Step 2, extrusion molding

[0019] The raw materials of the inner layer and the outer layer are respectively added to two hoppers of a double-material injection molding machine, the raw materials of the outer layer are obtained at a temperature of 275-280°C to obtain an outer layer melt, and the raw materials of the inner layer are obtained at a temperature of 270-275°C to obtain an inner layer melt, and the outer layer melt and the inner layer melt are processed into a double-layer PET preform by an injection molding composite process;

[0020] The injection molding pressure is 90-110 MPa, and the holding pressure time is 12-18 seconds.

[0021] An infrared thermal imager is used to monitor the temperature gradient in the mold cavity in real time, and feedback control is performed to control the temperature difference ΔT between the inner layer melt and the outer layer melt to be 5±0.5°C.

[0022] The viscosity of the outer layer melt is 280 Pa·s, and the viscosity of the inner layer melt is 350 Pa·s.

[0023] The injection speed of the outer layer melt is 80 mm / s, and the injection speed of the inner layer melt is 60 mm / s.

[0024] In order to complete the processing of the above-mentioned double-layer structure PIET bottle blank, the inventors found that in the actual implementation, due to the fact that most of the packaging bottles are transparent, there are often some impurities in the raw materials, and the existing injection molding equipment is directly used, which will cause the problems of black spots or air vents, and the quality of the packaging bottles in the subsequent blow molding process. At the same time, the inventors found through retrieval that CN108688126B proposes a drum-type large-area melt filter without fluctuation, which is essentially filtered from the outside to the inside because the filter screen is located on the material receiving side. Therefore, it is easy to cause the impurities to always be on the material receiving side of the filter screen. Even after adjusting the angle, the impurities are still on the side of the flow guide channel close to the filter screen, which causes the problem of "treating the symptoms but not the root cause". Therefore, a production equipment for double-layer PET bottle blank with high barrier performance is proposed to solve such problems, and the specific scheme includes:

[0025] Hot melt barrel, one end of the hot melt barrel is a feeding port, and the other end is a discharging port;

[0026] Spiral extrusion rod, the inside of the spiral extrusion rod is provided with the hot melt barrel;

[0027] Heating ring, the heating ring is provided with a plurality of heating rings and is installed on the outside of the hot melt barrel along the length direction of the hot melt barrel;

[0028] Extrusion head, the inside of the extrusion head is provided with an inner flow channel, the feeding port of the extrusion head is provided with a flow collecting pipe, the flow collecting pipe is provided with a flow straightening rod and a connecting port symmetrically distributed on both sides of the flow collecting pipe;

[0029] Double-out filter, the double-out filter is used to connect the connecting port of the flow collecting pipe and the discharging port of the hot melt barrel;

[0030] Molding die, the mold cavity in the molding die is communicated with the inner flow channel of the extrusion head.

[0031] In a more preferred scheme, the double-out filter comprises:

[0032] Side-out shunt pipe, the side-out shunt pipe is symmetrically arranged in two groups, and the discharging port of the side-out shunt pipe is connected with the connecting port of the flow collecting pipe;

[0033] Filter box, the filter box is symmetrically provided with two groups of side outlets, and the side outlets are connected with the feeding ports of the side-out shunt pipes;

[0034] Flange plate one, the flange plate one is fixed on one side of the filter box close to the hot melt barrel;

[0035] Flange plate two, the flange plate two is fixed on the side of the filter box away from the hot melt barrel;

[0036] Perforated ring, the perforated ring is rotatably installed in the filter box, and the side away from the hot melt barrel extends to the outside of the filter box;

[0037] The filter screen is located inside the porous ring.

[0038] A flow guide ring is placed inside the filter screen and connected to a porous ring.

[0039] The drive structure is mounted on flange two and is used to drive the perforated ring to rotate.

[0040] A plugging component is installed inside a porous ring and is used to seal the end of the porous ring away from the hot melt barrel.

[0041] In a more preferred embodiment, the dividing guide ring includes a support ring one and a support ring two. Both support ring one and support ring two are installed on the inner wall of the porous ring. Support ring one is located on the side closer to flange one, and support ring two is located on the side closer to flange two. Support ring one and support ring two are connected by multiple circumferentially spaced separators. The separators gradually deflect in the direction of the porous ring's movement along the direction closer to support ring two.

[0042] In a more preferred embodiment, the drive structure includes a blockage-removing motor and a worm gear mounted on the output end of the blockage-removing motor. The worm gear is rotatably mounted on flange two, and a worm wheel meshes with the outer side of the worm gear. The worm wheel is mounted on the outer side of the porous ring.

[0043] In a more preferred embodiment, the unblocking component includes:

[0044] The check ring is installed inside the second support ring. The inner wall of the check ring gradually shifts away from the flange one towards the unblocking side.

[0045] The main assembly slides and seals within the porous ring.

[0046] The sealing head is located inside the porous ring, and its outer diameter is between the inner diameter of the check ring and the inner diameter of the porous ring, and smaller than the outer diameter of the main assembly. The sealing head is integrally set on the side of the main assembly opposite to the flange and the side facing away from the main assembly has a sealing spherical surface.

[0047] The circulation pump is installed inside the sealing head;

[0048] Circulation channel one and circulation channel two are provided. Circulation channel one is radially distributed on the outside of the plugging head, and circulation channel two is axially distributed in the middle of the plugging head. Circulation channel one is connected to the inlet of the circulation pump, and circulation channel two is connected to the outlet of the circulation pump.

[0049] A barrier net is installed on the inlet side of the circulation channel one;

[0050] A one-way diaphragm is installed on the outlet side of circulation channel two;

[0051] The outer edge body is integrally arranged at one end of the main row piece, and the outer diameter size of the outer edge body is larger than the outer diameter size of the porous ring;

[0052] The guide rod is fixed at one end of the flange plate two and has the constraint body installed after penetrating the outer edge body at the other end, and the spring piece is sleeved outside the guide rod between the constraint body and the outer edge body;

[0053] The outer extrusion piece is arranged at one side of the worm relative to the outer edge body.

[0054] The fixed ring is arranged at one side of the outer extrusion piece and is provided with a plurality of outer convex structures distributed in the circumferential direction, the outer convex structures and the outer extrusion piece are one-to-one corresponding, the outer convex structure is provided with a guide groove, the inner extrusion block is axially and slidingly fitted in the guide groove, the inner extrusion block partially exposes the outside of the guide groove, and the thickness of the outer convex structure is 2-5 mm.

[0055] The annular groove is arranged at one side of the outer edge body opposite to the flange plate two, the annular groove is provided with the blocking plate installed at the groove opening, the inner extrusion ring is installed in the annular groove, the inner extrusion ring and the inner extrusion block are fixedly connected, the travel switch and the elastic piece are installed between the inner extrusion ring and the blocking plate, and the travel switch is used for controlling the opening and closing of the circulating pump.

[0056] In a more preferred scheme, the guide rod is located at the periphery of the fixed ring.

[0057] The outer convex structure is provided with a filter surface along the rotation direction of the outer extrusion piece.

[0058] In a more preferred scheme, the production equipment further comprises a pressure sensor one and a pressure sensor two, the pressure sensor one is used for detecting the melt pressure on the blocking side of the filter screen, and the pressure sensor two is used for detecting the melt pressure in the side outlet shunt pipe.

[0059] Compared with the prior art, the present application has the following beneficial effects:

[0060] 1. The PET double-layer bottle blank composite structure with high barrier composite inner layer and basic outer layer is adopted, first, the surface silane modified nano montmorillonite is selected, and the interface bonding force between the nano sheet layer and PET is enhanced through the silane coupling agent, the gradient transition zone structure (thickness 0.05-0.2 mm) is designed, the molecular chain mutual diffusion and entanglement is induced by using the melt temperature difference (ΔT = 5±0.5℃), the interface peeling strength is increased to ≥5 N / mm, and the inner layer peeling state dispersion structure (interlayer spacing ≥2 nm) is limited, so that the oxygen diffusion path is prolonged by about three times.

[0061] 2. The present application contacts the high-temperature low-viscosity outer layer melt (275℃, 280 Pa·s) with the low-temperature high-viscosity inner layer melt (270℃, 350 Pa·s) in the mold cavity, forming a temperature gradient field, and then the outer layer PET molecular chain (highly active) penetrates into the high-viscosity inner layer, with a diffusion depth of δ≈ , D is the diffusion coefficient D=10 -11 m 2 / s (270℃ PET), the contact time t=1.5-2s (initial pressure maintaining), and because the mold temperature is 85℃ (higher than the glass transition temperature Tg≈75℃ of PET), the interface melt stays in the semi-solid state for 8-10s, the molecular chain reacts with the amino group of silane through the unending carboxyl group to form a covalent bond (-CO-NH-), the entanglement density is increased by about 3 times, and then the gradient transition zone structure is obtained. Due to the existence of the gradient transition zone structure, stress concentration can be eliminated, the impact strength can be increased by about 40%, and the interface energy can reach 45mJ / m 2 , which is significantly higher than the cohesive energy of PET itself 35mJ / m 2 .

[0062] 3. The present application completes online filtering processing by adopting the inside-out filtering mode combined with rotating and switching the filter screen position. Compared with the outside-in filtering mode, the inside-out filtering mode does not cause the blockage to be congested on the filtering side (the outer side), is not easy to cause the filter screen to be broken during rotating and switching the filter screen position, and the blockage is mostly congested on the new filter screen position, which causes the problem of "treating the symptoms but not the root cause". The present application adopts the inside-out filtering mode to concentrate the blockage on the inner side of the filter screen, so that the filter screen is not damaged during rotating the filter screen, and the melt flow direction during rotating is collected to the non-return ring through the separation flow guide ring. At the same time, the outer extrusion part rotates relative to the fixed ring during rotating the porous ring, and the outer convex structure forces the blocking head to open the non-return ring. Then, the outer extrusion part moves inward to compress the elastomer and switches the travel switch to open the circulating pump, so that the blockage concentrated on the side of the non-return ring enters the outer side of the blocking head, is enriched in the area between the non-return ring and the blocking head, and the inner wall of the porous ring, and the pressure in the filter box is stabilized. BRIEF DESCRIPTION OF DRAWINGS

[0063] Figure 1 It is a schematic diagram of the double-layer PET bottle blank structure of the present application;

[0064] Figure 2 It is a schematic diagram of the production equipment of the present application;

[0065] Figure 3 It is a side view of the fairing rod of the present application;

[0066] Figure 4 It is an internal structure diagram of the double-out filter of the present application;

[0067] Figure 5 Structure diagram of the porous ring and the blocking member of the present application;

[0068] Figure 6 Structure diagram of the driving member of the present application;

[0069] Figure 7 Structure diagram of the partition flow guide ring of the present application;

[0070] Figure 8 Overall structure diagram of the fixed ring of the present application;

[0071] Figure 9 Overall structure side view of the fixed ring of the present application;

[0072] Figure 10 Structure diagram of the driving structure of the present application;

[0073] Figure 11 Top view of the production equipment of the present application.

[0074] In the figure: 1`, outer layer; 2`, inner layer; 3`, gradient transition zone;

[0075] 10, hot melt barrel; 20, spiral extrusion rod; 30, heating ring sleeve; 40, extrusion head; 41, manifold; 42, rectifier rod; 50, double-out filter; 51, side-out shunt pipe; 52, filter box; 53, flange plate one; 54, flange plate two; 541, blocking motor; 542, worm; 55, porous ring; 551, worm gear; 57, partition flow guide ring; 571, support ring one; 572, support ring two; 573, partition body; 58, blocking member; 581, non-return ring; 582, main blocking member; 583, blocking head; 584, circulating pump; 585, circulating flow passage one; 586, circulating flow passage two; 587, outer edge body; 588, spring member; 589, fixed ring; 5810, annular groove; 5811, outer convex structure; 5812, inner extrusion block; 5813, inner extrusion ring; 5814, guide rod; 5815, travel switch; 5816, blocking plate; 5817, elastic member; 5818, pressure sensor one; 5819, outer extrusion member; 5820, pressure sensor two; 60, forming mold. DETAILED DESCRIPTION

[0076] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments of the present application.

[0077] In the description of the present application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0078] As shown in Figure 1 A double-layer PET bottle blank with high barrier performance, comprising:

[0079] An outer layer 1` comprising a base PET resin;

[0080] An inner layer 2` comprising a PET composite material containing 5-15 wt% of surface silane-modified nanometer montmorillonite;

[0081] Wherein, the inner layer 2` and the outer layer 1` are integrally formed by co-injection molding, and a gradient transition zone 3` with a thickness of 0.05-0.2 mm is formed at the interface of the two layers, and the two-phase melt realizes molecular chain entanglement in the gradient transition zone 3`.

[0082] Wherein, the thickness of the inner layer 12` accounts for 15-25% of the total wall thickness of the bottle blank, and the thickness of the outer layer 1` accounts for 75-85%;

[0083] The particle size of the surface silane-modified nanometer montmorillonite is 20-80 nm, the interlayer spacing is ≥ 2.5 nm, and it is dispersed in a peeling state in the PET matrix.

[0084] The surface silane-modified nanometer montmorillonite is obtained by intercalating sodium-based montmorillonite with a silane coupling agent (such as KH-550), specifically:

[0085] The montmorillonite: silane is reacted in an ethanol / water solution (volume ratio 8:2) with pH=4.0 at a mass ratio of 1:0.3-0.5, stirred at 60°C for 6 hours, the amino group (-NH2) of the silane coupling agent reacts with the terminal carboxyl group of PET, and at the same time the siloxane group (-Si-OH) is bonded with the interlayer cation of montmorillonite, making the interlayer spacing expand from 1.2 nm to 3.2 nm, the tortuosity (τ) of the O2 diffusion path is raised from τ=1.8 to τ=6.5, the calculation formula: τ = 1 + (α·φ f ·L / d), where α=0.66, φ f =filler volume fraction, L / d=aspect ratio of sheet.

[0086] The modified montmorillonite and PET matrix (intrinsic viscosity 0.80 dL / g) were compounded by a twin-screw extruder through a melt extrusion dispersion process, temperature partition control: feeding section 180°C → mixing section 240°C → homogenization section 265°C, screw rotation speed 300-400 rpm (high shear force), vacuum devolatilization (-0.08 MPa), the use of high shear force makes the silane grafted montmorillonite layer peeling, the interlayer spacing reaches 2.8-3.5 nm.

[0087] The process steps are as follows:

[0088] Step 1, raw material treatment

[0089] The raw materials of the base PET resin were dried at 165±5°C for 5 hours;

[0090] The raw materials of the PET composite were dried at 130±10°C for 4 hours;

[0091] Step 2, extrusion molding

[0092] The raw materials of the inner layer 2` and the outer layer 1` were respectively added to the two hoppers of the double material injection molding machine, the raw materials of the outer layer 1` obtained the outer layer melt at a temperature of 275-280°C, and the raw materials of the inner layer 2` obtained the inner layer melt at a temperature of 270-275°C, and the outer layer melt and the inner layer melt were processed into double-layer PET bottle blanks by injection molding composite process;

[0093] Among them, the injection pressure is 90-110 MPa, and the holding time is 12-18 seconds;

[0094] The infrared thermal imager was used to monitor the temperature gradient in the mold cavity in real time, and the feedback control of the inner / outer layer melt temperature difference ΔT = 5±0.5°C;

[0095] The viscosity of the outer layer melt is 280 Pa·s, and the viscosity of the inner layer melt is 350 Pa·s;

[0096] The injection speed of the outer layer melt is 80 mm / s, and the injection speed of the inner layer melt is 60 mm / s.

[0097] Experimental data of PET bottle blank process of unmodified montmorillonite and modified montmorillonite:

[0098] The application can solve the contradiction between barrier property, interfacial bonding force and acid resistance (which cannot be considered in the prior art), reduce OTR to ≤0.004 cc / bottle·day (60% lower than EVOH / PET structure), have no delamination phenomenon after 30 days of storage in an acidic environment (pH=3.0), have a CO2 retention rate of ≥88% (75% of the comparative document CN1106067C), meet the 1-year shelf life requirement of high-CO2-content beverages such as craft beer, reduce the drying temperature of the inner layer material to 130°C (150°C for EVOH), reduce energy consumption by 15%, widen the injection molding temperature window to +5°C (traditional process +2°C), and increase the yield to 98%; and the migration amount of nanoparticles is ≤0.01 ppm (1 / 10 of the standard limit value of GB31604.1-2023).

[0099] As shown in Figure 1 、 Figure 11 , a production equipment of a double-layer PET bottle blank with high barrier property comprises:

[0100] A hot-melt barrel 10, one end of the hot-melt barrel 10 is a feeding port, and the other end is a discharging port;

[0101] A spiral extrusion rod 20, the spiral extrusion rod 20 is installed inside the hot-melt barrel 10;

[0102] A heating ring 30, the heating ring 30 is provided with a plurality of ring sleeves and is installed outside the hot-melt barrel 10 along the length direction of the hot-melt barrel 10;

[0103] An extrusion head 40, the inside of the extrusion head 40 is provided with an inner flow channel, the feeding port of the extrusion head 40 is installed with a flow collecting pipe 41, the flow collecting pipe 41 is installed with a flow straightening rod 42 and a connecting port symmetrically distributed on both sides of the flow collecting pipe 41;

[0104] A double-out filter 50, the double-out filter 50 is used to connect the connecting port of the flow collecting pipe 41 and the discharging port of the hot-melt barrel 10;

[0105] A forming die 60, the die cavity in the forming die 60 is communicated with the inner flow channel of the extrusion head 40.

[0106] The raw material enters from the hopper at the feeding port, flows to the extrusion head 40 through the hot-melt barrel and the spiral extrusion rod 20, obtains a melt under the action of the heating ring 30, completes the filtering of impurities through the double-out filter 50 before entering the extrusion head 40, and finally obtains a double-layer PET bottle blank in the die cavity of the forming die 60. It should be noted that the forming die 60 of the embodiment is a traditional double-layer bottle blank mold, for example, CN101376259B.

[0107] In the production equipment, as shown in Figure 3 、 5 , the double-out filter 50 comprises:

[0108] The side outlet shunt 51 is symmetrically arranged in two groups, and the outlet of the side outlet shunt 51 is connected with the connecting port of the collecting pipe 41.

[0109] The filter box 52 is symmetrically arranged with two groups of side outlets, and the side outlets are connected with the inlet of the side outlet shunt 51.

[0110] The flange plate one 53 is fixed on one side of the filter box 52 close to the hot melt cannon 10.

[0111] The flange plate two 54 is fixed on the side of the filter box 52 away from the hot melt cannon 10.

[0112] The perforated ring 55 is rotatably installed in the filter box 52 and extends to the outside of the filter box 52 away from the hot melt cannon 10.

[0113] The filter screen is arranged on the inside of the perforated ring 55.

[0114] The separation flow guide ring 57 is arranged on the inside of the filter screen and connected with the perforated ring 55.

[0115] The driving structure is installed on the flange plate two 54 and used to drive the rotation of the perforated ring 55.

[0116] The blockage removal member 58 is installed in the perforated ring 55 and used to block the end of the perforated ring 55 away from the hot melt cannon 10.

[0117] The production equipment further comprises a pressure sensor one 5818 and a pressure sensor two 5820, the pressure sensor one 5818 is used to detect the melt pressure on the blocking side of the filter screen, and the pressure sensor two 5820 is used to detect the melt pressure in the side outlet shunt 51.

[0118] The melt enters the collecting pipe 41 from the side outlet shunt 51 through the separation flow guide ring 57, the filter screen and the perforated ring 55 in sequence, and the impurities are intercepted when passing through the filter screen. When the pressure difference detected by the pressure sensor one 5818 and the pressure sensor two 5820 exceeds the set range, the driving structure drives the perforated ring 55 to rotate by a certain angle, so that the filter screen rotates by a certain angle to update the position of the inlet of the side outlet shunt 51 corresponding to the filter screen, and then the set pressure is restored, so that the problem of impurity blocking the screen port can be solved online. At the same time, the separation flow guide ring 57 guides the intercepted impurities to the tail of the perforated ring 55, and the whole double-out filter 50 adopts a heat preservation structure.

[0119] In the production equipment, as Figure 7As shown, the partition flow guide ring 57 comprises a support ring one 571 and a support ring two 572, both of which are mounted on the inner wall of the porous ring 55, the support ring one 571 is located near one side of the flange one 53, the support ring two 572 is located near one side of the flange two 54, and the support ring one 571 and the support ring two 572 are connected through a plurality of circumferential equidistant partition bodies 573, which gradually deflect along the running direction of the porous ring 55 in the direction close to the support ring two 572.

[0120] The support ring one 571 and the support ring two 572 are used as fixing surfaces, and the partition body 573 is used to constrain the filter screen and separate the impurities on the interception side of the filter screen, so as to avoid the impurities returning to the interception side of the filter screen at the new position of the filter screen under the action of the melt during the rotation of the filter screen.

[0121] In the production equipment, as shown in Figure 10 As shown, the driving structure comprises a unblocking motor 541 and a worm 542 mounted on the output end of the unblocking motor 541, the worm 542 is rotatably mounted on the flange two 54, and the outer side of the worm 542 is engaged with a worm gear 551, and the worm gear 551 is mounted on the outer side of the porous ring 55.

[0122] When the pressure value exceeds the set range, the system automatically identifies and controls the unblocking motor 541 to drive the worm 542 to rotate the worm gear 551 by a set angle, and when the pressure value returns to the set range, the control unblocking motor 541 stops working.

[0123] In the production equipment, as shown in Figure 4 , 5 , 6, 8, 10, the unblocking piece 58 comprises:

[0124] The reverse ring 581 is mounted on the inner side of the support ring two 572, and the inner wall of the reverse ring 581 gradually deviates from the blocking side in the direction away from the flange one 53;

[0125] The main unblocking piece 582 is slidingly and sealingly fitted in the porous ring 55;

[0126] The blocking head 583 is located on the inner side of the porous ring 55, and the outer diameter size is between the inner diameter of the reverse ring 581 and the inner diameter of the porous ring 55, and is smaller than the outer diameter size of the main unblocking piece 582, the blocking head 583 is integrally arranged on the side opposite to the flange one 53 of the main unblocking piece 582 and is provided with a blocking spherical surface on the side opposite to the main unblocking piece 582;

[0127] The circulating pump 584 is mounted in the inside of the blocking head 583;

[0128] A circulation flow channel one 585 and a circulation flow channel two 586, the circulation flow channel one 585 is radially distributed on the outside of the plugging head 583, the circulation flow channel two 586 is axially distributed in the middle of the plugging head 583, the circulation flow channel one 585 is connected with the inlet of the circulation pump 584, and the circulation flow channel two 586 is connected with the outlet of the circulation pump 584;

[0129] A barrier net, the barrier net is installed on the inlet side of the circulation flow channel one 585;

[0130] A one-way diaphragm, the one-way diaphragm is installed on the outlet side of the circulation flow channel two 586;

[0131] An outer rim body 587, the outer rim body 587 is integrally arranged on one end of the main discharge member 582, and the outer diameter size of the outer rim body 587 is greater than the outer diameter size of the porous ring 55;

[0132] A guide rod 5814, one end of the guide rod 5814 is fixed on the flange plate two 54, the other end is free to penetrate the outer rim body 587 and is provided with a constraint body, a spring member 588 is sleeved on the outer side of the guide rod 5814 between the constraint body and the outer rim body 587;

[0133] An outer extrusion member 5819, the outer extrusion member 5819 is provided with a plurality of and is circumferentially distributed on one side of the worm wheel 551 opposite to the outer rim body 587;

[0134] A fixing ring 589, the fixing ring 589 is provided with a plurality of outer convex structures 5811 circumferentially distributed on one side opposite to the outer extrusion member 5819, the outer convex structures 5811 and the outer extrusion member 5819 are one-to-one corresponding, the outer convex structures 5811 are provided with guide grooves, the inner extrusion blocks 5812 are axially and slidingly fitted in the guide grooves, the inner extrusion blocks 5812 partially expose the outer side of the guide grooves, and the thickness of the outer convex structures 5811 is 2-5 mm;

[0135] An annular groove 5810, the annular groove 5810 is arranged on the side of the outer rim body 587 away from the flange plate two 54, the annular groove 5810 is provided with a plugging plate 5816 at the groove opening, the inner extrusion ring 5813 is arranged in the annular groove 5810, the inner extrusion ring 5813 is fixedly connected with the inner extrusion blocks 5812, the travel switch 5815 and the elastic member 5817 are arranged between the inner extrusion ring 5813 and the plugging plate 5816, and the travel switch 5815 is used to control the opening and closing of the circulation pump 584.

[0136] The guide rod 5814 is located on the periphery of the fixing ring 589;

[0137] The outer convex structures 5811 are provided with filter surfaces in the rotation direction of the outer extrusion member 5819.

[0138] During the rotation of the porous ring 55, the outer extrusion 5819 will act on the outer convex structure 5811, forcing the main row 582 to move, and the sealing head 583 to open the discharge port of the check ring 581, with an opening distance of about 2-5mm, and the opening and closing has little effect on the pressure change in the filter box 52. Since during the rotation of the porous ring 55, the impurities between the partition bodies 573 will gather towards the check ring 581, and then with the increase of the rotation angle, the outer extrusion 5819 will extrude the exposed end of the inner extrusion block 5812, and then force the inner extrusion ring 5813 to switch the state of the travel switch 5815, to open the circulating pump 584 to realize the melt circulation, and in the circulation, the impurities are intercepted in the area between the check ring 581 and the sealing head 583 by the separation net, and when the equipment detects, the filter screen can be replaced. The outer extrusion 5819 and the inner extrusion block 5812 are made of wear-resistant materials, and when the outer extrusion 5819 acts to extrude the exposed inner extrusion block 5812 inward to be flush with the outer convex structure 5811, the travel switch 5815 controls the circulating pump 584 to be opened, and at the same time, the opening and closing ring on the inner extrusion ring 5813 opens the circulating channel 585, and the side of the inner extrusion block 5812 facing the outer extrusion 5819 adopts a slope structure to avoid the existence of the jamming problem.

[0139] The above is only a preferred embodiment of the present application, but the protection scope of the present application is not limited thereto. The alternatives can be partial structure, device, method step alternatives, or complete technical solutions. According to the technical solutions and inventive concepts of the present application, equivalent replacement or changes should be covered within the protection scope of the present application.

Claims

1. A double-layered PET preform having high barrier properties, characterized in that, The application relates to a double-layer PET bottle preform, which comprises an outer layer and an inner layer. The outer layer comprises a basic PET resin. The inner layer comprises a PET composite material containing 5-15 wt% of surface silane modified nano montmorillonite. The inner layer and the outer layer are integrally formed by co-injection molding, and a gradient transition zone with a thickness of 0.05-0.2 mm is formed at the interface between the two layers, and molecular chain entanglement is realized in the two-phase melt in the gradient transition zone. The thickness of the inner layer accounts for 15-25% of the total wall thickness of the bottle preform, and the thickness of the outer layer accounts for 75-85%. The surface silane modified nano montmorillonite has a particle size of 20-80 nm, an interlayer spacing of greater than or equal to 2.5 nm, and is in a peeling state in the PET matrix. The production process steps of the double-layer PET bottle preform are as follows: Step 1, raw material treatment The basic PET resin raw material is dried at 165±5 DEG C for 5 hours. The PET composite material raw material is dried at 130±10 DEG C for 4 hours. Step 2, extrusion molding The raw materials of the inner layer and the outer layer are respectively added into two barrels of a double-material injection molding machine, the raw material of the outer layer is obtained at a temperature of 275-280 DEG C to obtain the outer layer melt, the raw material of the inner layer is obtained at a temperature of 270-275 DEG C to obtain the inner layer melt, and the outer layer melt and the inner layer melt are processed into the double-layer PET bottle preform through an injection molding composite process. The injection pressure is 90-110 MPa, and the pressure maintaining time is 12-18 seconds. An infrared thermal imager is used to monitor the temperature gradient in the mold cavity in real time, and feedback control is performed on the temperature difference between the inner layer melt and the outer layer melt, that is, Delta T = 5±0.5 DEG C. The viscosity of the outer layer melt is 280 Pa.s, and the viscosity of the inner layer melt is 350 Pa.s. The injection speed of the outer layer melt is 80 mm / s, and the injection speed of the inner layer melt is 60 mm / s.

2. A double-layer PET preform with high barrier performance according to claim 1, which is produced by using the following equipment, characterized in that, The device comprises: a hot melt barrel (10), one end of the hot melt barrel (10) being a feeding port and the other end being a discharging port; a spiral extrusion rod (20), the spiral extrusion rod (20) being internally provided with the hot melt barrel (10); a heating ring (30), the heating ring (30) being provided with a plurality of heating rings and being arranged on the outside of the hot melt barrel (10) along the length direction of the hot melt barrel (10); an extrusion head (40), the inside of the extrusion head (40) being provided with an internal flow channel, a flow converging pipe (41) being arranged at the feeding port of the extrusion head (40), and a rectifier rod (42) and a connecting port being symmetrically arranged at both sides of the flow converging pipe (41) being arranged in the flow converging pipe (41); a double-out filter (50), the double-out filter (50) being used for connecting the connecting port of the flow converging pipe (41) and the discharging port of the hot melt barrel (10); a molding mold (60), a mold cavity in the molding mold (60) being communicated with the internal flow channel of the extrusion head (40).

3. The double-layered PET preform with high barrier property according to claim 2, characterized in that, The double-out filter (50) comprises: a side-out shunt pipe (51), the side-out shunt pipe (51) being symmetrically arranged with two groups, the discharging port of the side-out shunt pipe (51) being connected with the connecting port of the flow converging pipe (41); a filter box (52), the filter box (52) being symmetrically provided with two groups of side outlets, the side outlets being connected with the feeding ports of the side-out shunt pipes (51); a flange plate one (53), the flange plate one (53) being fixed on one side of the filter box (52) close to the hot melt barrel (10). The flange two (54) is fixed on the side of the filter box (52) away from the hot melt lance (10); The porous ring (55) is rotatably installed in the filter box (52) and extends to the outside of the filter box (52) on the side away from the hot melt lance (10); The filter screen is distributed on the inside of the porous ring (55); The separation flow guide ring (57) is arranged on the inside of the filter screen and connected with the porous ring (55); The driving structure is installed on the flange two (54) and used to drive the rotation of the porous ring (55); The blockage removal member (58) is installed in the porous ring (55) and used to block the end of the porous ring (55) away from the hot melt lance (10).

4. The double-layered PET preform with high barrier property according to claim 3, characterized in that, The separation flow guide ring (57) comprises a support ring one (571) and a support ring two (572), both of which are installed on the inner wall of the porous ring (55), the support ring one (571) is located on the side close to the flange one (53), the support ring two (572) is located on the side close to the flange two (54), the support ring one (571) and the support ring two (572) are connected through a plurality of circumferentially equidistantly distributed separation bodies (573), and the separation bodies (573) gradually deflect along the running direction of the porous ring (55) in the direction close to the support ring two (572).

5. The double-layered PET preform with high barrier property according to claim 4, characterized in that, The driving structure comprises a blockage removal motor (541) and a worm (542) installed on the output end of the blockage removal motor (541), the worm (542) is rotatably installed on the flange two (54), the outside of the worm (542) is engaged with a worm gear (551), and the worm gear (551) is installed on the outside of the porous ring (55).

6. The double-layered PET preform with high barrier property according to claim 5, characterized in that, The blockage removal member (58) comprises: The reverse prevention ring (581) is installed on the inside of the support ring two (572), the inner wall of the reverse prevention ring (581) gradually deflects away from the flange one (53); The main blockage removal member (582) is slidingly and sealingly fitted in the porous ring (55); The blocking head (583) is located on the inside of the porous ring (55), the outer diameter size of the blocking head (583) is between the inner diameter of the reverse prevention ring (581) and the inner diameter of the porous ring (55) and is smaller than the outer diameter size of the main blockage removal member (582), the blocking head (583) is integrally arranged on the side opposite to the flange one (53) of the main blockage removal member (582) and is provided with a blocking spherical surface on the side opposite to the main blockage removal member (582); The circulating pump (584) is installed in the inside of the blocking head (583); The circulating flow channel one (585) is radially distributed on the outside of the blocking head (583), the circulating flow channel two (586) is axially distributed in the middle part of the blocking head (583), the circulating flow channel one (585) is connected with the inlet of the circulating pump (584), and the circulating flow channel two (586) is connected with the outlet of the circulating pump (584); The blocking net is installed on the inlet side of the circulating flow channel one (585). The one-way diaphragm is installed at the outlet side of the circulation flow channel two (586); The outer edge body (587) is integrally arranged at one end of the main discharge member (582), and the outer diameter size of the outer edge body (587) is greater than the outer diameter size of the porous ring (55); The guide rod (5814) is fixed at one end of the flange plate two (54) and is provided with a constraint body at the other end after penetrating through the outer edge body (587), and the outer side of the guide rod (5814) between the constraint body and the outer edge body (587) is sleeved with a spring member (588); The outer extrusion member (5819) is provided with a plurality of outer extrusion members (5819) and is distributed in the circumferential direction on one side of the worm wheel (551) opposite to the outer edge body (587); The fixing ring (589) is provided with a plurality of outer convex structures (5811) distributed in the circumferential direction on one side opposite to the outer extrusion member (5819), the outer convex structures (5811) and the outer extrusion member (5819) are one-to-one corresponding, the outer convex structures (5811) are provided with guide grooves, the inner extrusion blocks (5812) are axially and slidingly fitted in the guide grooves, the inner extrusion blocks (5812) partially protrude from the outer side of the guide grooves, and the thickness of the outer convex structures (5811) is 2-5mm; The annular groove (5810) is arranged on the side of the outer edge body (587) opposite to the flange plate two (54), the annular groove (5810) is provided with a sealing plate (5816) at the groove opening, the inner extrusion ring (5813) is arranged in the annular groove (5810), the inner extrusion ring (5813) and the inner extrusion block (5812) are fixedly connected, the travel switch (5815) and the elastic member (5817) are arranged between the inner extrusion ring (5813) and the sealing plate (5816), and the travel switch (5815) is used for controlling the opening and closing of the circulating pump (584).

7. The double-layered PET preform with high barrier property according to claim 6, characterized in that, The guide rod (5814) is located at the periphery of the fixing ring (589); The outer convex structure (5811) is provided with a filter surface in the rotation direction of the outer extrusion member (5819).

8. The double-layered PET preform with high barrier property according to claim 7, characterized in that, The production equipment further comprises a pressure sensor one (5818) and a pressure sensor two (5820), the pressure sensor one (5818) is used for detecting the melt pressure on the blocking side of the filter screen, and the pressure sensor two (5820) is used for detecting the melt pressure in the side outlet shunt pipe (51).

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