Preparation method of mobile phone cover plate substrate co-extrusion protective film

Abstract

The invention relates to the field of co-extruded films, in particular to a preparation method of a mobile phone cover plate substrate co-extruded protective film, which comprises the following steps: S1, preparing raw materials of each layer in proportion, and respectively adding the raw materials into an extruder of each layer for melting and plasticizing; s2, according to the arrangement sequence of all the layers of extruders, the molten and plasticized plasticized materials are sequentially conveyed to a tape casting machine, tape casting rollers in the tape casting machine pull out all the layers of molten and plasticized plasticized materials in sequence, and then all the layers of molten and plasticized plasticized materials are wound with one another; s3, conveying the intertwined plasticized materials to a secondary heating head, and carrying out secondary heating on the intertwined plasticized materials section by section by the secondary heating head; s4, the plasticized materials subjected to secondary heating are conveyed to a co-extrusion head, and the co-extrusion head presses the intertwined plasticized materials and then conveys the plasticized materials to a film blowing die head; s5, the film blowing die head blows out the bubble film to form a protective film body; and S6, after the protective film body is cooled, the protective film body is cut through a cutting mechanism and then bonded to the cover plate or the substrate.

Description

Technical Field

[0001] The present invention relates to the field of co-extruded films, and more specifically, to a method for preparing a co-extruded protective film for a mobile phone cover substrate. Background Art

[0002] With the development of social economy, people's living standards are gradually improving, so the application of mobile phones is becoming more and more extensive. The co-extruded protective film of the mobile phone cover substrate can protect the mobile phone cover substrate. Therefore, it has been widely used.

[0003] However, the current co-extruded protective film is generally heated only once during the production process, and then the heated multiple layers of molten plasticized materials are sequentially blended together for film blowing. However, this co-extruded protective film only uses heating and pressing to fuse the materials of each layer together. Since it is only heated once and no additives are added during the heating process, stratification is inevitable after long-term use.

[0004] Therefore, it is necessary to propose a method for preparing a co-extruded protective film for a mobile phone cover substrate that solves the above problems. Summary of the invention

[0005] In order to overcome at least one defect (shortcoming) of the above-mentioned prior art, the present invention provides a method for preparing a co-extruded protective film for a mobile phone cover substrate.

[0006] In order to solve the above technical problems, the technical solution of the present invention is as follows: A method for preparing a co-extruded protective film for a mobile phone cover substrate comprises the following steps:

[0007] S1, after the raw materials of each layer are prepared in proportion, they are added into the extruders of each layer for melting and plasticization;

[0008] S2, according to the arrangement order of each layer of extruders, the molten plasticized plasticized material is sequentially transported to the tape casting machine, and the tape casting roller in the tape casting machine sequentially pulls out each layer of the molten plasticized plasticized material and makes them entangled with each other;

[0009] S3, the mutually entangled plasticized materials are transported to a secondary heating head, and the secondary heating head performs secondary heating on the mutually entangled plasticized materials section by section;

[0010] S4, the plasticized material after secondary heating is transported to a co-extrusion head, and the co-extrusion head presses the mutually entangled plasticized materials and then transports them to a film blowing die head;

[0011] S5, the film blowing die head blows out the bubble film to form a protective film body;

[0012] S6, after the protective film body is cooled, the protective film body is cut by a cutting mechanism and then bonded to the cover plate or the substrate;

[0013] Furthermore, the step S1 includes:

[0014] S11, adding free polyetherimide, polyamideimide and polyetheretherketone in a ratio of 1:1:3 to an extruder of the first layer for melt plasticization to obtain a plasticized material for the first layer of the film body;

[0015] S12, adding polyethylene terephthalate, linear low-density polyethylene and polypropylene in a ratio of 1:2:4 to an extruder of the second layer for melt plasticization to obtain a plasticized material for the second layer film body;

[0016] S13, adding ethylene butene copolymer, ethylene hexene copolymer and ethylene octene copolymer in a ratio of 2:3:1 to the extruder of the third layer for melt plasticization to obtain a plasticized material for the third layer film.

[0017] Furthermore, the step S2 comprises:

[0018] S21, conveying the molten plasticized material to the tape casting machine in sequence according to the arrangement order of the extruders in each layer;

[0019] S22, the tape casting machine performs preliminary lamination on the molten plasticized materials extruded by each layer of the extruders;

[0020] S23, after the melt-plasticized plasticized material is initially pressed, it is transported to a casting roller, and during the transporting process, the melt-plasticized plasticized material is evenly sprayed with a polymer processing aid;

[0021] S24, the casting roller stretches and rotates the preliminarily pressed plasticized material so that the melted plasticized material is entangled with each other after being pulled out.

[0022] Furthermore, the step S3 includes:

[0023] S31, conveying the mutually entangled plasticized materials to a heating inspection head;

[0024] S32, the stretcher in the heating inspection head detects the diameter of the plasticized materials after being intertwined. When the diameter of the plasticized materials after being intertwined is less than 1 cm, the heating inspection head transports the plasticized materials after being intertwined to the secondary heating head. When the diameter of the plasticized materials after being intertwined is greater than 1 cm, the heating inspection head stretches the plasticized materials after being intertwined again until the diameter of the plasticized materials after being intertwined is less than 1 cm. At this time, the heating inspection head transports the plasticized materials after being intertwined to the secondary heating head.

[0025] Furthermore, the step S4 includes:

[0026] S41, after the secondary heating head performs secondary heating on the mutually entangled plasticized materials, until the plasticized materials reach 190-220 degrees Celsius;

[0027] S42, the conveyor conveys the secondary heated plasticized material to the co-extrusion head, and the co-extrusion head presses the secondary heated plasticized material;

[0028] S43, the pressed plasticized material is conveyed to the film blowing die head by the conveyor.

[0029] Furthermore, the step S5 comprises:

[0030] S51, blowing warm air on both the inner and outer sides of the film blowing die head, so that the protective film body is blown out and initially formed;

[0031] S52, respectively switching the wind temperatures inside and outside the film blowing die head so that the difference in the wind temperatures inside and outside the film blowing die head is within 10 degrees Celsius, thereby promoting rapid shaping of the protective film body.

[0032] Furthermore, the step S6 comprises:

[0033] S61, after the protective film body is cooled, the film blowing die head stops blowing;

[0034] S62, the cutting mechanism cuts the protective film body in sequence and bonds the protective mold body to the cover plate or the substrate.

[0035] Furthermore, after the protective film is formed, the thickness ratio of the first film layer, the second film layer and the third film layer is 1:3:6. In practical applications, the discharge efficiency can be used to control the discharge amount of each layer of the extruder, thereby controlling the thickness of each layer of the film.

[0036] Furthermore, the temperature inside and outside the film blowing die head changes every five minutes. Since the temperature inside and outside the film blowing die head changes every five minutes, it is convenient for rapid molding of the protective film body, and due to the temperature change, the occurrence of wrinkles on the protective film body is also reduced.

[0037] Furthermore, the polymer processing aid is a fluorine polymer processing aid. In practical applications, the polymer processing aid can also be made of other materials.

[0038] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0039] The method for preparing the co-extruded protective film for a mobile phone cover substrate disclosed in the present invention comprises the following steps: mixing the raw materials of each layer in proportion, melting and plasticizing them, and pulling out the melted and plasticized materials of each layer and making them intertwine with each other. Compared with the prior art, the connection strength between the layers can be strengthened, and after being intertwined with each other, the melted and plasticized materials are heated and stretched for a second time to fully mix the melted and plasticized materials with the polymer processing aid. Therefore, the co-extruded protective film for the mobile phone cover substrate can be better prevented from inevitably delaminating after long-term use. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is a flow chart of the method for preparing the co-extruded protective film of the mobile phone cover substrate in the present invention. DETAILED DESCRIPTION

[0041] The drawings are only used for illustrative purposes and should not be construed as limitations on this patent. In order to better illustrate this embodiment, some parts of the drawings may be omitted, enlarged, or reduced, and do not represent the size of the actual product. For those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0042] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation" and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. It can be said that the internal connection of two components is connected. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. The technical solution of the present invention is further explained below in conjunction with the accompanying drawings and embodiments.

[0043] like Figure 1 As shown, a method for preparing a co-extruded protective film for a mobile phone cover substrate comprises the following steps:

[0044] S1, after the raw materials of each layer are prepared in proportion, they are added into the extruders of each layer for melting and plasticization;

[0045] S2, according to the arrangement order of each layer of extruders, the molten plasticized plasticized material is sequentially transported to the tape casting machine, and the tape casting roller in the tape casting machine sequentially pulls out each layer of the molten plasticized plasticized material and makes them entangled with each other;

[0046] S3, the mutually entangled plasticized materials are transported to a secondary heating head, and the secondary heating head performs secondary heating on the mutually entangled plasticized materials section by section;

[0047] S4, the plasticized material after secondary heating is transported to a co-extrusion head, and the co-extrusion head presses the mutually entangled plasticized materials and then transports them to a film blowing die head;

[0048] S5, the film blowing die head blows out the bubble film to form a protective film body;

[0049] S6, after the protective film body is cooled, the protective film body is cut by a cutting mechanism and then bonded to the cover plate or the substrate;

[0050] Wherein, step S1 comprises:

[0051] S11, adding free polyetherimide, polyamideimide and polyetheretherketone in a ratio of 1:1:3 to an extruder of the first layer for melt plasticization to obtain a plasticized material for the first layer of the film body;

[0052] S12, adding polyethylene terephthalate, linear low-density polyethylene and polypropylene in a ratio of 1:2:4 to an extruder of the second layer for melt plasticization to obtain a plasticized material for the second layer film body;

[0053] S13, adding ethylene butene copolymer, ethylene hexene copolymer and ethylene octene copolymer in a ratio of 2:3:1 to the extruder of the third layer for melt plasticization to obtain a plasticized material for the third layer film.

[0054] Step S2 includes:

[0055] S21, conveying the molten plasticized material to the tape casting machine in sequence according to the arrangement order of the extruders in each layer;

[0056] S22, the tape casting machine performs preliminary lamination on the molten plasticized materials extruded by each layer of the extruders;

[0057] S23, after the melt-plasticized plasticized material is initially pressed, it is transported to a casting roller, and during the transporting process, the melt-plasticized plasticized material is evenly sprayed with a polymer processing aid;

[0058] S24, the casting roller stretches and rotates the preliminarily pressed plasticized material so that the melted plasticized material is entangled with each other after being pulled out.

[0059] Wherein, step S3 comprises:

[0060] S31, conveying the mutually entangled plasticized materials to a heating inspection head;

[0061] S32, the stretcher in the heating inspection head detects the diameter of the plasticized materials after being intertwined. When the diameter of the plasticized materials after being intertwined is less than 1 cm, the heating inspection head transports the plasticized materials after being intertwined to the secondary heating head. When the diameter of the plasticized materials after being intertwined is greater than 1 cm, the heating inspection head stretches the plasticized materials after being intertwined again until the diameter of the plasticized materials after being intertwined is less than 1 cm. At this time, the heating inspection head transports the plasticized materials after being intertwined to the secondary heating head.

[0062] Step S4 includes:

[0063] S41, after the secondary heating head performs secondary heating on the mutually entangled plasticized materials, until the plasticized materials reach 190-220 degrees Celsius;

[0064] S42, the conveyor conveys the secondary heated plasticized material to the co-extrusion head, and the co-extrusion head presses the secondary heated plasticized material;

[0065] S43, the pressed plasticized material is conveyed to the film blowing die head by the conveyor.

[0066] In the present invention, step S5 includes:

[0067] S51, blowing warm air on both the inner and outer sides of the film blowing die head, so that the protective film body is blown out and initially formed;

[0068] S52, respectively switching the wind temperatures inside and outside the film blowing die head so that the difference in the wind temperatures inside and outside the film blowing die head is within 10 degrees Celsius, thereby promoting rapid shaping of the protective film body.

[0069] Furthermore, the step S6 comprises:

[0070] S61, after the protective film body is cooled, the film blowing die head stops blowing;

[0071] S62, the cutting mechanism cuts the protective film body in sequence and bonds the protective mold body to the cover plate or the substrate.

[0072] After the protective film body is formed, the thickness ratio of the first film layer, the second film layer and the third film layer is 1:3:6. In practical applications, the discharge amount of each layer of the extruder can be controlled by the discharge efficiency, so as to control the thickness of each layer of the film body. Among them, the temperature on both sides of the inner and outer sides of the film blowing die head changes every five minutes. Since the temperature inside and outside the film blowing die head changes every five minutes, it is convenient for the rapid molding of the protective film body, and due to the change in temperature, the occurrence of wrinkles in the protective film body is also reduced. In the present invention, the compound processing aid is a fluorine polymer processing aid. In practical applications, the polymer processing aid can also be made of other materials.

[0073] Example

[0074] In this embodiment, when it is necessary to produce a co-extruded protective film for a mobile phone cover substrate, free polyetherimide, polyamide-imide and polyetheretherketone in a weight ratio of 1:1:3 can be put into the first extruder according to production needs, polyethylene terephthalate, linear low-density polyethylene and polypropylene in a weight ratio of 1:2:4 can be put into the second extruder, and ethylene butene copolymer, ethylene hexene copolymer and ethylene octene copolymer in a weight ratio of 2:3:1 can be put into the third extruder, and the heating temperatures of the three extruders can be controlled according to needs, and the raw materials in the three extruders can be melted and plasticized at the same time.

[0075] After the raw materials of the three extruders are melted and plasticized, the melted and plasticized plasticized materials are transported to the cast film machine in sequence according to the arrangement order of each extruder. At this time, the cast film machine will perform preliminary pressing on the melted and plasticized plasticized materials extruded by the three extruders. During the preliminary pressing, one side of the three extruded melted and plasticized plasticized materials will be initially bonded together to achieve preliminary pressing. After the melted and plasticized plasticized materials are initially pressed, the melted and plasticized plasticized materials are transported to the cast film roller, and during the conveying process, the melted and plasticized plasticized materials are evenly sprayed with a polymer processing aid. Since the polymer processing aid is evenly sprayed on the surface of the plasticized material, in order to make the material better bonded, the cast film roller will stretch and rotate the initially pressed plasticized material, so that the melted and plasticized plasticized materials are entangled with each other after being pulled out. Due to the stretching and rotation, the polymer processing aid can be better integrated on the surface of the plasticized material, which is convenient for subsequent bonding with the mobile phone cover substrate.

[0076] When the mutually entangled plasticized materials are pulled out and entangled with each other, they will be transported to the heating inspection head. The stretcher in the heating inspection head will detect the diameter of the mutually entangled plasticized materials. When the diameter of the mutually entangled plasticized materials is less than 1 cm, the heating inspection head will transport the mutually entangled plasticized materials to the secondary heating head. When the diameter of the mutually entangled plasticized materials is greater than 1 cm, the heating inspection head will stretch the mutually entangled plasticized materials again until the diameter of the mutually entangled plasticized materials is less than 1 cm. At this time, the heating inspection head will transport the mutually entangled plasticized materials to the secondary heating head. At this time, The hot head will reheat the plasticized materials after being entangled with each other until the plasticized materials reach 190-220 degrees Celsius; the secondary heating can make the plasticized materials after being entangled with each other mix again, avoiding the situation that incomplete pressing is caused by the temperature reduction during the mutual winding process, and through the secondary heating, the polymer processing aid can also be better mixed in the plasticized material. At this time, the conveyor conveys the plasticized material after the secondary heating to the co-extrusion head, and the co-extrusion head presses the plasticized material after the secondary heating. The pressed plasticized material is conveyed to the film blowing die head under the action of the conveyor.

[0077] In actual applications, warm air can be blown on both the inner and outer sides of the film blowing die head so that the protective film body is blown out and initially formed. There is a temperature difference of less than 10 degrees Celsius between the warm air on the inner and outer sides, which is convenient for the protective film body to be quickly formed. In addition, the temperature of the warm air on the inner and outer sides should be changed every five minutes. This can reduce the occurrence of wrinkles on the protective film body. After the protective film body is cooled, the film blowing die head stops blowing, and the cutting mechanism cuts the protective film body in sequence and bonds the protective mold body to the cover plate or substrate.

[0078] In the figure, the description of the positional relationship is only for illustrative purposes and should not be understood as a limitation on this patent; obviously, the above embodiments of the present invention are only examples for clearly illustrating the present invention, and are not limitations on the implementation methods of the present invention. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made on the basis of the above description. It is not necessary and impossible to list all the implementation methods here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the claims of the present invention.

Claims

1. A method for preparing a co-extruded protective film for a mobile phone cover substrate, characterized in that: The following steps are involved: S1, after the raw materials of each layer are prepared in proportion, they are added into the extruders of each layer for melting and plasticization; S2, according to the arrangement order of each layer of extruders, the molten plasticized plasticized material is sequentially transported to the tape casting machine, and the tape casting roller in the tape casting machine sequentially pulls out each layer of the molten plasticized plasticized material and makes them entangled with each other; S3, the mutually entangled plasticized materials are transported to a secondary heating head, and the secondary heating head performs secondary heating on the mutually entangled plasticized materials section by section; S4, the plasticized material after secondary heating is transported to a co-extrusion head, and the co-extrusion head presses the mutually entangled plasticized materials and then transports them to a film blowing die head; S5, the film blowing die head blows out the bubble film to form a protective film body; S6, after the protective film body is cooled, the protective film body is cut by a cutting mechanism and then bonded to the cover plate or the substrate.

2. The method for preparing a co-extruded protective film for a mobile phone cover substrate according to claim 1, characterized in that: The step S1 comprises: S11, adding free polyetherimide, polyamideimide and polyetheretherketone in a ratio of 1:1:3 to an extruder of the first layer for melt plasticization to obtain a plasticized material for the first layer of the film body; S12, adding polyethylene terephthalate, linear low-density polyethylene and polypropylene in a ratio of 1:2:4 to an extruder of the second layer for melt plasticization to obtain a plasticized material for the second layer film body; S13, adding ethylene butene copolymer, ethylene hexene copolymer and ethylene octene copolymer in a ratio of 2:3:1 to the extruder of the third layer for melt plasticization to obtain a plasticized material for the third layer film.

3. The method for preparing a co-extruded protective film for a mobile phone cover substrate according to claim 1, characterized in that: The step S2 comprises: S21, conveying the molten plasticized material to the tape casting machine in sequence according to the arrangement order of the extruders in each layer; S22, the tape casting machine performs preliminary lamination on the molten plasticized materials extruded by each layer of the extruders; S23, after the melt-plasticized plasticized material is initially pressed, it is transported to a casting roller, and during the transporting process, the melt-plasticized plasticized material is evenly sprayed with a polymer processing aid; S24, the casting roller stretches and rotates the preliminarily pressed plasticized material so that the melted plasticized material is entangled with each other after being pulled out.

4. The method for preparing a co-extruded protective film for a mobile phone cover substrate according to claim 1, characterized in that: The step S3 comprises: S31, conveying the mutually entangled plasticized materials to a heating inspection head; S32, the stretcher in the heating inspection head detects the diameter of the plasticized materials after being intertwined. When the diameter of the plasticized materials after being intertwined is less than 1 cm, the heating inspection head transports the plasticized materials after being intertwined to the secondary heating head. When the diameter of the plasticized materials after being intertwined is greater than 1 cm, the heating inspection head stretches the plasticized materials after being intertwined again until the diameter of the plasticized materials after being intertwined is less than 1 cm. At this time, the heating inspection head transports the plasticized materials after being intertwined to the secondary heating head. S33, the secondary heating head performs secondary heating on the mutually entangled plasticized materials section by section.

5. The method for preparing a co-extruded protective film for a mobile phone cover substrate according to claim 1, characterized in that: The step S4 comprises: S41, after the secondary heating head performs secondary heating on the mutually entangled plasticized materials, until the plasticized materials reach 190-220 degrees Celsius; S42, the conveyor conveys the secondary heated plasticized material to the co-extrusion head, and the co-extrusion head presses the secondary heated plasticized material; S43, the pressed plasticized material is conveyed to the film blowing die head by the conveyor.

6. The method for preparing a co-extruded protective film for a mobile phone cover substrate according to claim 1, characterized in that: The step S5 comprises: S51, blowing warm air on both the inner and outer sides of the film blowing die head, so that the protective film body is blown out and initially formed; S52, respectively switching the wind temperatures inside and outside the film blowing die head so that the difference in the wind temperatures inside and outside the film blowing die head is within 10 degrees Celsius, thereby promoting rapid shaping of the protective film body.

7. The method for preparing a co-extruded protective film for a mobile phone cover substrate according to claim 1, characterized in that: The step S6 comprises: S61, after the protective film body is cooled, the film blowing die head stops blowing; S62, the cutting mechanism cuts the protective film body in sequence and bonds the protective mold body to the cover plate or the substrate.

8. The method for preparing a co-extruded protective film for a mobile phone cover substrate according to claim 2, characterized in that: After the protective film body is formed, the thickness ratio of the first film layer, the second film layer and the third film layer is 1:3:

6.

9. The method for preparing a co-extruded protective film for a mobile phone cover substrate according to claim 1, characterized in that: The temperatures inside and outside the film blowing die head are changed every five minutes.

10. The method for preparing a co-extruded protective film for a mobile phone cover substrate according to claim 3, characterized in that: The polymer processing aid is a fluorine polymer processing aid.

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