阅读说明：本技术 一种复合petg热收缩膜及其制备系统 (Composite PETG (polyethylene terephthalate glycol) heat shrinkable film and preparation system thereof ) 是由 吴培服 丁炎森 王琪 于 2021-08-31 设计创作，主要内容包括：本申请公开了一种复合PETG热收缩膜及其制备系统,所述复合PETG热收缩膜,由挤出成型的A层表面层、B层芯层和C层底层构成,所述的A层和C层分别设置于B层的两侧,其中：所述A层和C层,均包括PETG以及总质量的5.5wt％～9.5wt％的PETG功能料切片,B层包括PS以及总质量的14.5wt％～21.5wt％的PS功能料切片。本申请通过添加功能母料的方式,对PETG层和PS层分别进行了功能调整,使得调整之后的共挤时的模头温度可以降低至240℃左右,同时可以有效消除界面波纹缺陷,并避免膜层分离。本申请的复合PETG热收缩膜兼具PETG和PS的长处,外侧由于是PETG易于印刷,对温度敏感度低；内层是PS,因此收缩力也减小了,便于收缩。(The application discloses compound PETG heat shrink film and preparation system thereof, compound PETG heat shrink film comprises extrusion moulding's A layer surface layer, B layer sandwich layer and C layer bottom, A layer and C layer set up respectively in the both sides on B layer, wherein: the layer A and the layer C both comprise PETG and PETG functional material slices accounting for 5.5-9.5 wt% of the total mass, and the layer B comprises PS and PS functional material slices accounting for 14.5-21.5 wt% of the total mass. This application is through the mode that adds the function masterbatch, has carried out the function adjustment respectively to PETG layer and PS layer for die head temperature when crowded altogether after the adjustment can reduce to about 240 ℃, can effectively eliminate interface ripple defect simultaneously, and avoid the rete separation. The composite PETG heat shrinkable film has the advantages of both PETG and PS, and the outer side of the composite PETG heat shrinkable film is easy to print and low in temperature sensitivity; the inner layer is PS, so the shrinkage force is also reduced, facilitating shrinkage.)

1. The composite PETG heat shrinkable film is composed of an A layer surface layer, a B layer core layer and a C layer bottom layer which are formed by extrusion molding, wherein the A layer and the C layer are respectively arranged at two sides of the B layer, and the composite PETG heat shrinkable film is characterized in that: the layer A and the layer C both comprise PETG and PETG functional material slices accounting for 5.5-9.5 wt% of the total mass, the PETG functional material slices comprise PETG slices, nano boron nitride, aluminate, polydimethylsiloxane and potassium chloride, the layer B comprises PS and PS functional material slices accounting for 14.5-21.5 wt% of the total mass, and the PS functional material slices comprise PS slices, polyethylene oxide, silicon dioxide and ethylene-vinyl acetate copolymer.

2. The composite PETG heat shrinkable film as claimed in claim 1, wherein the PETG functional material slice comprises the following components in parts by weight: 80-95 parts of PETG slices, 2-5 parts of nano boron nitride, 1-2 parts of aluminate, 6-10 parts of polydimethylsiloxane and 2-3 parts of potassium chloride.

3. The composite PETG heat shrinkable film as claimed in claim 1, wherein the PS functional material slices comprise the following components in parts by weight: 70-80 parts of PS slices, 5-10 parts of polyethylene oxide, 2-5 parts of silicon dioxide and 5-10 parts of ethylene-vinyl acetate copolymer.

4. A system for preparing composite PETG heat shrinkable film according to one of claims 1 to 3, comprising at least PETG melt conveying equipment (100), PS melt conveying equipment (101) and a film co-extrusion device (200); the device is characterized in that the film co-extrusion device (200) is provided with a surface layer runner (201), a core layer runner (202) and a bottom layer runner (203) which are respectively used for forming an A layer surface layer, a B layer core layer and a C layer bottom layer; the PETG melt conveying equipment (100) conveys the PETG melt into two parts through a PETG melt conveying pump (300) and respectively conveys the PETG melt to a surface layer runner (201) and a bottom layer runner (203); the PS melt conveying device (101) conveys the PS melt to the core layer runner (202) through a PS melt conveying pump (301); the conveying pressure of the PS melt conveying pump (301) is 5-8 times that of the PETG melt conveying pump (300).

5. The preparation system according to claim 4, characterized in that the PETG melt conveying device (100) comprises at least one PETG melt discharge tank (10), the PETG melt discharge tank (10) is provided with a PETG melt input pipeline (20), a PETG functional material melt input pipeline (30) and a PETG melt output pipeline (40) connected with the PETG melt conveying pump (10).

6. The system for preparing PETG slices according to claim 5, wherein at least one PETG flow distribution valve (50) is arranged in the PETG melt input pipeline (20), and the PETG flow distribution valves (50) synchronously convey one part of the PETG melt to the PETG melt discharge tank (10) and the rest part of the PETG melt to a PETG slicing device (60) for preparing PETG slices through pipelines.

7. The preparation system as recited in claim 6, characterized in that the PETG slices prepared by the PETG slicing apparatus (60) are used for preparing PETG functional material slices, which include PETG slices, nano boron nitride, aluminate, polydimethylsiloxane, and potassium chloride.

8. A production system according to claim 4, wherein the PS melt delivery device (101) comprises at least one PS melt discharge tank (11), the PS melt discharge tank (11) having a PS melt input pipe (21), a PS functional melt input pipe (31) and a PS melt output pipe (41) connected to a PS melt delivery pump (301).

9. The production system according to claim 8, wherein the PS melt input pipe (21) is provided with at least one PS flow distribution valve (51), and the PS flow distribution valve (51) synchronously feeds a part of the PS melt to the PS melt discharge tank (11) and feeds the remaining part of the PS melt to a PS slicing apparatus (61) for producing PS slices through the pipe.

10. The manufacturing system according to claim 9, wherein the PS slices manufactured by the PS slicing apparatus (61) are used for manufacturing PS functional material slices, and the PS functional material slices include PS slices, polyethylene oxide, silica, and ethylene-vinyl acetate copolymer.

Technical Field

The application relates to the technical field of production of heat shrinkable films, in particular to a composite PETG heat shrinkable film and a preparation system thereof.

Background

Heat shrinkable films are a common packaging film. In packaging application, the idea of heat shrinkage is often utilized to realize a skin effect or bundling and wrapping; while using it to protect the contents from contamination or damage. The principle of thermal contraction of the thermal contraction film is that when the film is produced, a molecular chain segment with mobility is oriented at the melting point or the glass transition temperature, and then the film is cooled to the crystallization point or the glass transition temperature to quickly solidify the molecular orientation; when reheated above the melting point or glass transition temperature, the polymer segments will regain mobility, and the originally oriented molecular segments will begin to curl, adopt an orientation that macroscopically appears as film shrinkage.

The heat shrinkable films currently applied to the packaging field mainly include polyvinyl chloride (PVC) heat shrinkable films, Polyethylene (PE) heat shrinkable films, Polystyrene (PS), modified polyethylene terephthalate (PETG) heat shrinkable films, multilayer co-extruded polyolefin heat shrinkable films (POF) and the like. When the PVC heat shrinkable film is burnt, a large amount of hydrogen chloride and dioxin gas are often generated, which is not beneficial to recovery and treatment and does not meet the requirement of environmental protection, so the application is limited. PE and POF heat shrinkable films have good flexibility, impact resistance, strong tear resistance, difficult damage, moisture resistance and wide shrinkage range, but have poor printing performance. The PS heat shrinkable film has good stability and appearance in the shrinking process, but is sensitive to temperature, has high requirement on storage conditions, is difficult to control thickness uniformity, is easy to generate fish eyes, is easy to cause poor color register due to thickness change, and is printed by using special ink and solvent, so that the cost is high. The PETG shrink film has good thickness uniformity, excellent printing effect, insensitivity to temperature and convenient storage, transportation and storage. However, the PETG heat shrinkable film has large shrinkage force, and wrinkles are easy to appear when the PETG heat shrinkable film is shrunk in a shrinkage furnace after being sleeved with labels.

To overcome the drawbacks of single component heat shrink films, heat shrink films have also appeared in recent years in the form of multilayer composites. For example, CN 111976252 a discloses a flexible thermal contraction composite film formed by tape casting, the structure of the flexible thermal contraction composite film is an a/B/a three-layer composite structure, wherein the a layer is a surface layer and is mainly made of a mixture of PETG resin and a opening agent; the layer B is a core layer and mainly made of styrene-butadiene block copolymer resin (SBS) and Maleic Anhydride (MAH). The prior art adopts special core layer components, claims that the shrinkage force of a PETG layer can be reduced through the core layer, solves the problems of membrane surface wrinkling and membrane layer separation, and has the characteristics of wide shrinkage range, good flexibility, excellent printing performance and the like.

Although the prior art discloses three-layer coextruded composite PETG heat shrink films, it has been found in practical reproduction that the core material is not arbitrarily chosen. Two problems are very complicated in co-extrusion and cannot be solved by simple limited experiments. On the one hand, the problem of interlayer adhesion formed by different polymers is that separation of the film layers easily occurs. On the other hand, when the viscosity and the fluidity of different polymers are different greatly, in a compounding area of the co-extrusion die head, the low-viscosity melt may wrap the high-viscosity melt to generate an unstable flowing phenomenon, and finally, the extruded composite film will have a ripple state at a film layer interface, so that the performance and the appearance of the composite film are influenced. In addition, the gloss, haze and other properties of the composite film are affected by the material of the film layer, and thus are not desired by those skilled in the art.

Disclosure of Invention

The technical problem to be solved by the present application is to provide a composite PETG heat shrinkable film and a preparation system thereof, so as to reduce or avoid the aforementioned problems.

In order to solve the technical problem, the application provides a composite PETG heat shrinkable film, which is composed of an A layer surface layer, a B layer core layer and a C layer bottom layer which are formed by extrusion molding, wherein the A layer and the C layer are respectively arranged on two sides of the B layer, and the composite PETG heat shrinkable film is characterized in that: the layer A and the layer C both comprise PETG and PETG functional material slices accounting for 5.5-9.5 wt% of the total mass, the PETG functional material slices comprise PETG slices, nano boron nitride, aluminate, polydimethylsiloxane and potassium chloride, the layer B comprises PS and PS functional material slices accounting for 14.5-21.5 wt% of the total mass, and the PS functional material slices comprise PS slices, polyethylene oxide, silicon dioxide and ethylene-vinyl acetate copolymer.

Preferably, the PETG functional material slice comprises the following components in parts by weight: 80-95 parts of PETG slices, 2-5 parts of nano boron nitride, 1-2 parts of aluminate, 6-10 parts of polydimethylsiloxane and 2-3 parts of potassium chloride.

Preferably, the PS functional material slice comprises the following components in parts by weight: 70-80 parts of PS slices, 5-10 parts of polyethylene oxide, 2-5 parts of silicon dioxide and 5-10 parts of ethylene-vinyl acetate copolymer.

Preferably, the thicknesses of the A layer, the B layer and the C layer are respectively 5-10 μm, 20-40 μm and 5-10 μm, and the total thickness of the composite PETG heat shrinkable film is 30-60 μm. Further preferably, the thicknesses of the layer A, the layer B and the layer C are respectively 6-7 μm, 26-27 μm and 6-7 μm, and the total thickness of the composite PETG heat shrinkable film is 38-41 μm.

The application also provides a preparation system of the composite PETG heat shrinkable film, which at least comprises PETG melt conveying equipment, PS melt conveying equipment and a film co-extrusion device; the thin film co-extrusion device is provided with a surface layer runner, a core layer runner and a bottom layer runner which are respectively used for forming an A layer surface layer, a B layer core layer and a C layer bottom layer; the PETG melt conveying equipment is used for conveying the PETG melt into a surface layer flow channel and a bottom layer flow channel respectively in two strands through a PETG melt conveying pump; the PS melt conveying equipment conveys the PS melt to the core layer runner through a PS melt conveying pump; the conveying pressure of the PS melt conveying pump is 5-8 times of that of the PETG melt conveying pump.

Preferably, the PETG melt conveying equipment at least comprises a PETG melt discharging tank, and the PETG melt discharging tank is provided with a PETG melt input pipeline, a PETG functional material melt input pipeline and a PETG melt output pipeline connected with a PETG melt conveying pump.

Preferably, at least one PETG flow distribution valve is arranged in the PETG melt input pipeline, and the PETG flow distribution valve synchronously conveys one part of PETG melt to the PETG melt discharge tank and conveys the rest part of PETG melt to a PETG slicing device for preparing PETG slices through a pipeline.

Preferably, the PETG slices prepared by the PETG slicing device are used for preparing PETG functional material slices, and the PETG functional material slices comprise PETG slices, nano boron nitride, aluminate, polydimethylsiloxane and potassium chloride.

Preferably, the PS melt conveying equipment at least comprises a PS melt discharging tank, and the PS melt discharging tank is provided with a PS melt input pipeline, a PS functional material melt input pipeline and a PS melt output pipeline connected with a PS melt conveying pump.

Preferably, at least one PS flow distribution valve is arranged in the PS melt input pipeline, and the PS flow distribution valve synchronously conveys one part of the PS melt to the PS melt discharge tank and conveys the rest part of the PS melt to a PS slicing device for preparing PS slices through the pipeline.

Preferably, the PS slices prepared by the PS slicing apparatus are used for preparing PS functional material slices, and the PS functional material slices include PS slices, polyethylene oxide, silica, and ethylene-vinyl acetate copolymer.

This application is through the mode that adds the function masterbatch, has carried out the function adjustment respectively to PETG layer and PS layer for die head temperature when crowded altogether after the adjustment can reduce to about 240 ℃, can effectively eliminate interface ripple defect simultaneously, and avoid the rete separation. Meanwhile, better indexes such as the glossiness and the haze of the composite film can be kept.

Drawings

The drawings are only for purposes of illustrating and explaining the present application and are not to be construed as limiting the scope of the present application.

Wherein, fig. 1 shows a schematic cross-sectional structure diagram of the composite PETG heat shrinkable film of the present application.

Fig. 2 shows a schematic of a manufacturing system for a compounded PETG heat shrink film of the present application.

Detailed Description

In order to more clearly understand the technical features, objects, and effects of the present application, embodiments of the present application will now be described with reference to the accompanying drawings. Wherein like parts are given like reference numerals.

As shown in fig. 1, there is shown a schematic cross-sectional structure of a composite PETG heat shrink film according to one embodiment of the present application. Referring to fig. 1, the composite PETG heat shrinkable film of the present application is a three-layer structure co-extruded heat shrinkable film, and is composed of an extruded a layer surface layer, a B layer core layer and a C layer bottom layer, wherein the a layer and the C layer are respectively disposed on both sides of the B layer, both the a layer and the C layer are PETG layers containing functional material slices, the B layer is a PS layer containing functional material slices, wherein the a layer and the C layer have a thickness of 5-10 μm, the B layer has a thickness of 20-40 μm, and the total thickness of the composite PETG heat shrinkable film is 30-60 μm. Preferably, the thicknesses of the layer A, the layer B and the layer C are respectively 6-7 μm, 26-27 μm and 6-7 μm, and the total thickness of the composite PETG heat shrinkable film is 38-41 μm. The width of the composite PETG heat shrinkable film is 250-8700mm, and preferably 250-1500 mm.

The layer A and the layer C are made of the same material and respectively comprise PETG and PETG functional material slices accounting for 5.5-9.5 wt% of the total mass, and the PETG functional material slices comprise PETG slices, nano boron nitride, aluminate, polydimethylsiloxane and potassium chloride.

The layer B comprises PS and PS functional material slices accounting for 14.5 wt% -21.5 wt% of the total mass, and the PS functional material slices comprise PS slices, polyethylene oxide, silicon dioxide and ethylene-vinyl acetate copolymer. The ethylene-vinyl acetate copolymer is preferably an ethylene-vinyl acetate copolymer which is sold by Mitsui corporation of Japan and has the trademark of Evaflex 550, and the mass percent of the contained vinyl acetate polymer is 14 percent.

In the layer a and the layer C, the PETG functional material slices can be obtained by extruding and granulating by using equipment such as an extruder after the raw material components are uniformly mixed. Similarly, the PS functional material chips can be obtained by uniformly mixing the raw material components, extruding the mixture by using an extruder, and granulating the mixture.

Preferably, the PETG functional material slice comprises the following components in parts by weight: 80-95 parts of PETG slices, 2-5 parts of nano boron nitride, 1-2 parts of aluminate, 6-10 parts of polydimethylsiloxane and 2-3 parts of potassium chloride.

Further preferably, the PS functional material slice comprises the following components in parts by weight: 70-80 parts of PS slices, 5-10 parts of polyethylene oxide, 2-5 parts of silicon dioxide and 5-10 parts of ethylene-vinyl acetate copolymer.

The composite PETG heat shrinkable film has the advantages of both PETG and PS, and the outer side of the composite PETG heat shrinkable film is easy to print and low in temperature sensitivity; the inner layer is PS, so the shrinkage force is also reduced, facilitating shrinkage.

Of course, it should be appreciated that there are many problems with using PS as the core layer. Firstly, the viscosity of molten Polypropylene (PS) is much lower than that of polyethylene terephthalate-1, 4-cyclohexanedimethanol ester (PETG), and the flow rate of PS is much higher than that of PETG during co-extrusion. Secondly, the normal extrusion temperature of PS is typically around 210 ℃, whereas the normal extrusion temperature of PETG is typically around 260 ℃, with a 50 ℃ extrusion temperature difference. Although PS is relatively less temperature sensitive, increasing its extrusion temperature to the same level as PETG makes it difficult to control its extrusion quality.

In the composite area of the co-extrusion die head, the flow rate of the melt close to the wall surface is reduced, and the flow rate of the melt in the middle is higher. When the middle layer adopts PS with higher fluidity, the flow rate difference can be further amplified, and the probability of forming ripple defects on an extrusion interface can be increased. One possible means of reducing defects is to increase the die temperature so that the flow rate of the outside melt is increased, but the flow rate of PETG is not temperature sensitive, while increasing the die temperature is detrimental to the extrusion quality of PS. Another possible measure is to minimize the thickness of the PS so that it cannot wrap the PETG. However, since the price of PS is much cheaper than PETG, reducing the thickness of the PS layer will undoubtedly increase the cost of a product of comparable thickness and is therefore not commercially acceptable. In summary, it is theoretically difficult to laminate PETG and PS, and it is difficult to obtain a high-quality composite heat shrinkable film.

This application is through the mode that adds the function masterbatch, has carried out the function adjustment respectively to PETG layer and PS layer for die head temperature when crowded altogether after the adjustment can reduce to about 240 ℃, can effectively eliminate interface ripple defect simultaneously, and avoid the rete separation.

Referring now to fig. 2, by way of specific example, the system and method for manufacturing a composite PETG heat shrink film of the present application will be described in detail while demonstrating the comparative performance of the prepared composite PETG heat shrink film.

Specifically, the present application provides a preparation system of the composite PETG heat shrinkable film, as shown in fig. 2, the preparation system at least comprises a PETG melt conveying device 100, a PS melt conveying device 101, and a film co-extrusion device 200. In the particular embodiment shown in FIG. 2, the film coextrusion apparatus 200 is shown as a representative representation in cross-section of a coextrusion die, and it will be understood by those skilled in the art that FIG. 2 shows only a schematic representation of the structure that represents the inventive modifications and combinations of the prior art that are closely related to the present application, that the structure that is not shown in FIG. 2, that is not an improvement of the prior art, that is known in the art, and that other structures that are not shown in the figures are known to those skilled in the art, and that portions of the structure that are not shown in the figures to achieve the technical concepts and solutions of the present application should be present, and that the present application will not repeat the description of these prior art structures that are clearly present in order to make the present application clearer.

As shown, the film co-extrusion apparatus 200 has a surface layer runner 201, a core layer runner 202 and a bottom layer runner 203 for forming an a-layer surface layer, a B-layer core layer and a C-layer bottom layer, respectively; the PETG melt conveying equipment 100 conveys the PETG melt into two parts through a PETG melt conveying pump 300 and respectively conveys the PETG melt to the surface layer runner 201 and the bottom layer runner 203; the PS melt transport apparatus 101 transports the PS melt to the core layer runner 202 by a PS melt transport pump 301. The composite PETG heat shrinkable film is prepared by the known procedures of quenching, preheating, stretching, shaping, cooling, rolling and the like after the thick sheet is obtained by extruding through a coextrusion die head of the thin film coextrusion device 200.

As mentioned above, because it is difficult to obtain a high-quality composite heat shrinkable film by compounding PETG and PS, and it is necessary to overcome the problems of temperature, film layer separation, and interface corrugation defects, the present application adjusts the components of each film layer, and in addition, it adjusts the extrusion pressure for forming each film layer, that is, increases the extrusion pressure of the core layer located in the middle of the film layers, preferably, the extrusion pressure of the core layer needs to be 5-8 times of the extrusion pressure of the surface layer and the bottom layer, and specifically, in the preparation system of fig. 2, the delivery pressure of the PS melt delivery pump 301 needs to be 5-8 times of that of the PETG melt delivery pump 300.

Further, as shown, the PETG melt conveying device 100 at least comprises a PETG melt discharging tank 10, and the PETG melt discharging tank 10 has a PETG melt input pipe 20, a PETG functional material melt input pipe 30, and a PETG melt output pipe 40 connected to the PETG melt conveying pump 10. Similarly, the PS melt transfer device 101 comprises at least one PS melt discharge tank 11, and the PS melt discharge tank 11 has a PS melt input pipe 21, a PS functional melt input pipe 31, and a PS melt output pipe 41 connected to a PS melt transfer pump 301.

The PETG melt and the PS melt respectively input through the PETG melt input pipe 20 and the PS melt input pipe 21 may be directly from a melt discharge tank at a polymerization terminal of the corresponding polymer, or may be from melts obtained by remelting spherical materials, granular materials, sheet materials, and the like of the corresponding polymer.

In addition, the PETG functional material melt input through the PETG functional material melt input pipeline 30 is melt obtained by blending and then melting PETG functional material slices and PETG slices, wherein the weight percentage of the PETG functional material slices and the PETG slices is 5.5-9.5 wt% of the total mass. The PS functional material melt input through the PS functional material melt input pipeline 31 is a melt obtained by blending and then melting 14.5 wt% -21.5 wt% of PS functional material slices and PS slices in total mass.

In the illustrated embodiment, at least one PETG flow distribution valve 50 is disposed in the PETG melt input conduit 20, and the PETG flow distribution valve 50 simultaneously delivers a portion of the PETG melt to the PETG melt discharge tank 10 and the remaining portion of the PETG melt through the conduit to a PETG slicing apparatus 60 for preparing PETG slices. In another embodiment, the PETG slices produced by the PETG slicing apparatus 60 may be used to produce PETG functional material slices, as previously described, including PETG slices, nano boron nitride, aluminate, polydimethylsiloxane, and potassium chloride.

Similarly, at least one PS flow distribution valve 51 is disposed in the PS melt input pipe 21, and the PS flow distribution valve 51 synchronously delivers a part of the PS melt to the PS melt discharge tank 11 and delivers the remaining part of the PS melt to a PS slicing apparatus 61 for preparing PS slices through a pipe. In yet another embodiment, the PS slices prepared by the PS slicing apparatus 61 are used to prepare PS functional material slices, which include PS slices, polyethylene oxide, silica, and ethylene-vinyl acetate copolymer, as also described above.

The main purpose of the PETG slicing device 60 and the PS slicing device 61 is to balance the feeding of the melt so as to avoid the thickness deviation of the film caused by the fluctuation of the melt flow during the subsequent co-extrusion. For example, a flow rate metering device (not shown) may be provided in the line for feeding the melt to the film coextrusion apparatus 200, and when a deviation in the fed flow rate is detected, the opening degree of the flow rate distribution valves 50 and 51 is adjusted to increase or decrease the melt feed rate to the slicing devices 60 and 61, thereby ensuring the melt supply to the film coextrusion apparatus. Meanwhile, when the film co-extrusion device 200 breaks down or stops, in order to avoid waste caused by melt loss, redundant melts can be prepared into slices. Thus, it will be understood by those skilled in the art that the slices prepared by the slicing apparatus 60, 61 may be used as the slices for preparing the functional material slices as described above, but the slices used to prepare the functional material slices may also be derived in part or in whole from commercially available or previously prepared raw materials, and need not necessarily be the slices prepared by the illustrated slicing apparatus 60, 61.

In one embodiment, 80-95 parts by weight of PETG chips prepared by the PETG chip slicing apparatus 60, 2-5 parts by weight of nano boron nitride, 1-2 parts by weight of aluminate, 6-10 parts by weight of polydimethylsiloxane and 2-3 parts by weight of potassium chloride are uniformly mixed, and then extruded and granulated by using equipment such as an extruder to obtain PETG functional material chips. Then, the prepared PETG functional material slices are uniformly mixed with the PETG slices prepared by the PETG slicing device 60 again according to 5.5 wt% -9.5 wt% of the total mass and then melted to obtain the PETG functional material melt which is input into the PETG melt discharging tank 10 through the PETG functional material melt input pipeline 30.

In another embodiment, the PS pellets of the PS functional material can be obtained by uniformly mixing 70 to 80 parts by weight of the PS pellets prepared by the PS pellet mill 61, 5 to 10 parts by weight of polyethylene oxide, 2 to 5 parts by weight of silica, and 5 to 10 parts by weight of an ethylene-vinyl acetate copolymer, and then extruding and granulating the mixture by using a device such as an extruder. Then, the prepared PS functional material slices can be uniformly mixed with the PS slices prepared by the PS slice device 61 again according to 14.5 wt% -21.5 wt% of the total mass and then melted to obtain the PS functional material melt which is input into the PS melt discharge tank 11 through the PS functional material melt input pipeline 31.

It should be noted that, in the present application, both the PETG melt and the PS melt are continuously conveyed in two directions simultaneously, that is, a part of the melt is conveyed in the coextrusion direction and the rest of the melt is continuously conveyed in the slicing direction without stopping through the flow distribution valves 50 and 51. When the melt flow in the co-extrusion direction fluctuates, the melt flow in the slicing direction can be increased or decreased. That is to say, the fuse-element in this application is all incessant continuous transport in two directions, therefore the fuse-element of two directions can be transferred each other and is joined in marriage the agent, when the film is crowded device 200 altogether and takes place the problem and shut down, and slice device 60, 61 can be carried to unnecessary fuse-element to realize the incessant purpose of avoiding extravagant of carrying of fuse-element, but also can guarantee through two-way regulation transport that the film thickness that co-extrusion came is even.

Examples

(1) The PETG functional material slices are prepared according to the raw material component ratios (parts by weight) shown in the following table.

	Component 1	Component 2	Component 3	Component 4	Component 5	Component 6
							PETG section	80	88	95	80	88	95
Nano boron nitride	2	4	5	2	0	0
							Aluminate ester	1	1.5	2	1	5.5	7
Polydimethylsiloxane	6	8	10	0	8	0
							Potassium chloride	2	2.5	3	8	2.5	13

(2) The PS functional material chips were prepared according to the raw material component ratios (parts by weight) shown in the following table.

	Component 7	Component 8	Component 9	Component 10	Component 11	Component 12
							PS section	70	75	80	70	75	80
Polyethylene oxide	5	8	10	0	10	0
							Silicon dioxide	2	4	5	7	2	12
EVA	5	7	10	5	0	0

(3) The composite PETG heat shrinkable film is prepared by the raw material components according to the weight portion shown in the following table.

(4) The test results (examples 1 to 3) of the prepared composite PETG heat shrinkable film are listed in the following table.

Comparative examples 1 to 3 used as comparison all have defects of film layer separation, corrugated stripes and the like in different degrees, and other detection values are shown in the following table, and due to the problems of difficult extrusion and film layer separation, the film layer thickness and the mechanical property cannot be accurately measured.

It should be appreciated by those skilled in the art that while the present application is described in terms of several embodiments, not every embodiment includes only a single embodiment. The description is thus given for clearness of understanding only, and it is to be understood that all matters in the embodiments are to be interpreted as including all technical equivalents which are encompassed by the claims and are to be interpreted as combined with each other in a different embodiment so as to cover the scope of the present application.

The above description is only illustrative of the present invention and is not intended to limit the scope of the present invention. Any equivalent alterations, modifications and combinations that may be made by those skilled in the art without departing from the spirit and principles of this application shall fall within the scope of this application.