High-strength matte polyester film for car clothing and preparation method of high-strength matte polyester film

Abstract

The invention discloses a high-strength matte polyester film for car clothing and a preparation method thereof, and belongs to the technical field of polyester films, the high-strength matte polyester film comprises the following raw materials in parts by weight: 7-8 parts of PET polyester chips, 50-80 parts of matte master batch, 10-30 parts of white non-fluorescent polyester chips and 0.8-1 part of a nano reinforcing agent; the preparation method comprises the following steps: S1, stirring and mixing the raw materials in parts by weight, pre-crystallizing, drying, transferring into an extruder, filtering by a filter, extruding to a machine head to form a melt film, and cooling by a cold drum to form a film casting sheet; s2, transferring the film casting sheet into a two-way stretching machine, passing through a longitudinal stretching preheating section, a longitudinal stretching shaping section and a transverse stretching shaping section, and stretching to obtain the high-strength matte polyester film for the car cover, the production process is simple and easy to operate, the cost is relatively low, and the prepared polyester film has the characteristics of high haze, high wear resistance and good mechanical properties.

Description

Technical Field

[0001] The invention belongs to the technical field of polyester films, and particularly relates to a high-strength matte polyester film for car covers and a preparation method thereof. Background Art

[0002] Car cover is a thin film pasted on the surface of the car, which is widely used in the decoration and protection of the car's appearance. It plays a good protective role against frequent scratches, scratches from hard objects such as metal, and paint aging. In particular, the hazy feeling of matte car cover is deeply loved by consumers and has broad market prospects. Polyethylene terephthalate film (referred to as polyester film) has excellent mechanical properties, thermal properties and excellent chemical resistance, and has been widely used in the field of car cover.

[0003] The existing matte polyester film for car covers generally adopts the melt blending method to add silica into polyester chips to achieve the matte effect of the film; when the haze and gloss requirements of the matte polyester film are low, adding a small amount (3wt%) of silica can achieve it well, but if the haze and gloss standards are to be further improved, adding a large amount of silica will make the problems of uneven dispersion and interface compatibility prominent, thereby causing the strength of the matte polyester film to be seriously reduced; although the copolymerization modification method can meet the requirements of high haze and mechanical properties of the matte polyester film, its process is complicated and the preparation cost is high.

[0004] Therefore, how to prepare a matte polyester film for car covers with high strength and good mechanical properties is a technical problem that needs to be solved at present. Summary of the invention

[0005] The object of the present invention is to provide a high-strength matte polyester film for car cover and a preparation method thereof, so as to solve the problems in the background technology.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A high-strength matte polyester film for car covers, comprising the following raw materials in parts by weight:

[0008] 7-8 parts of PET polyester chips, 50-80 parts of matte masterbatch, 10-30 parts of white non-fluorescent polyester chips and 0.8-1 parts of nano-enhancer; the nano-enhancer is prepared by the following steps:

[0009] Zirconium tetrachloride and terephthalic acid are added to N,N-dimethylformamide, stirred and mixed evenly at room temperature, then stirred and reacted at 110-130°C for 24 hours, cooled to room temperature, washed with N,N-dimethylformamide and ethanol, centrifuged, and vacuum dried at 100°C for 10 hours to obtain a nano-enhancer.

[0010] Furthermore, the usage ratio of zirconium tetrachloride, terephthalic acid and N,N-dimethylformamide is 0.94-1.17 g: 0.67-0.83 g: 60-80 mL.

[0011] Furthermore, the matte masterbatch is prepared by the following steps:

[0012] Step A1, adding a coupling agent to an ethanol aqueous solution, stirring and dissolving at 60° C., then adding silicon dioxide with a particle size of 3-5 μm and keeping the temperature for reaction for 3-5 hours, filtering, washing, and drying in an oven at 100° C. for 2 hours to obtain modified silicon dioxide;

[0013] Step A2: adding modified silica and PET polyester chips into a twin-screw extruder, performing melt mixing at 270-280° C., extruding, cooling, and pelletizing to obtain matte masterbatch.

[0014] The invention improves the dispersibility and compatibility of silicon dioxide in a polyester matrix at a conventional dosage by modifying silicon dioxide with a particle size of 3-5 μm, and also avoids the adsorption effect of silicon dioxide on nano-enhancer and titanium dioxide.

[0015] Furthermore, the usage ratio of the coupling agent, silicon dioxide and ethanol aqueous solution is 1.5-2g:8g:100mL; and the concentration of the ethanol aqueous solution is 75wt%.

[0016] Furthermore, the coupling agent is KH570; KH570 can not only react with hydroxyl groups on the surface of silica, reduce the hydroxyl content on the surface of silica, effectively avoid the agglomeration of silica, and promote the dispersion of silica in the matte polyester film; it can also react with the polyester matrix, thereby improving the interface action and interaction force between the modified silica and the polyester matrix.

[0017] Furthermore, the mass ratio of the modified silica to the PET polyester chips is 3-4: 100. When the modified silica is used to melt-blend and modify the PET polyester chips, the content of the modified silica should not be too high, otherwise the modified silica will still show negative effects.

[0018] Furthermore, the white non-fluorescent polyester chips are prepared by melt mixing titanium dioxide with a particle size of 1.5 μm and PET polyester chips, and the titanium dioxide content is 60wt%. Titanium dioxide can not only enhance the weather resistance and wear resistance of the polyester chips, making them more durable when attached to the surface of the car paint, but also has good hiding power and light reflectivity, and can improve the haze of the polyester film.

[0019] A method for preparing a high-strength matte polyester film for car cover comprises the following steps:

[0020] Step S1, mixing PET polyester chips, matte masterbatch, white non-fluorescent polyester chips and nano-enhancer in parts by weight of the formula, pre-crystallizing at 170-175° C., drying at 155° C. for 4 hours, and then transferring to an extruder, filtering through a filter to a die head to form a melt film, and cooling through a cold drum to form a film casting sheet;

[0021] Step S2, transferring the film cast into a biaxial stretching machine, and stretching to obtain a high-strength matte polyester film for car covers with a thickness of 50 um after passing through a longitudinal stretching preheating section, a longitudinal stretching shaping section and a transverse stretching shaping section.

[0022] Furthermore, in step S1, the filter temperature is 275°C, the die head temperature is 270-275°C; the cold drum speed is 43m / min, and the cold drum temperature is 25-27°C;

[0023] Furthermore, in step S2, the temperature of the longitudinal stretching preheating section is 70-89°C, the temperature of the longitudinal stretching shaping section is 27-35°C, and the temperature of the transverse stretching shaping section is 235-240°C.

[0024] Beneficial effects of the present invention:

[0025] The invention uses zirconium salt and terephthalic acid as raw materials, prepares an organic metal framework structure nano-enhancer through coordination reaction, and introduces the nano-enhancer into a matte polyester film. On the one hand, the nano-enhancer acts as a nucleating agent, and the nano-enhancer with terephthalic acid as a ligand and a large specific surface area can fully contact with the polyester substrate, so that its heterogeneous nucleation effect is more obvious, and the crystallization rate and crystallinity of the polyester substrate are significantly improved. On the other hand, the nano-enhancer itself has flexibility, which can overcome the deformation limitation of silicon dioxide and titanium dioxide, and can be used as a toughening agent; in addition, the nano-enhancer has a high specific surface area and a porous structure, which can increase the scattering of light in the polyester film, thereby improving the haze; therefore, a small amount of nano-enhancer can bring performance improvements in haze and mechanical strength to the matte polyester film;

[0026] The present invention uses PET polyester chips as a substrate, controls the dosage of matte masterbatch, white non-fluorescent polyester chips and nano-enhancer, and melt-blends the above raw materials to achieve the grading effect of modified silicon dioxide, titanium dioxide and nano-enhancer on different scales. Micron-sized silicon dioxide and titanium dioxide are commonly used fillers for matte polyester films. The unique optical properties of silicon dioxide and titanium dioxide can increase the scattering of light in the polyester film, thereby improving the haze of the polyester film. The nano-enhancer can further improve the haze of the polyester film at the nano level due to its structural characteristics. Silicon dioxide and titanium dioxide, as rigid particles, can significantly improve the strength and wear resistance of the polyester film and maintain good processing performance. The nano-enhancer, as a complementary material, uses its role as a nucleating agent and a toughening agent to further improve the strength and toughness of the polyester film. In the process of melt blending, the modified silicon dioxide, titanium dioxide and nano-enhancer can be well dispersed in the polyester matrix to reduce agglomeration. Through their respective characteristics and functions, they work together to improve the haze and mechanical properties of the matte polyester film.

[0027] The matte polyester film prepared by melt blending modification and biaxial stretching has a simple production process, is easy to operate, and has low cost. The prepared polyester film has the characteristics of high haze, high wear resistance and good mechanical properties. DETAILED DESCRIPTION

[0028] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] Example 1

[0030] This embodiment provides a matte masterbatch, which is prepared by the following steps:

[0031] Step A1, add 1.5g KH570 to 100mL 75wt% ethanol aqueous solution, stir and dissolve at 60°C, then add 8g silica with a central particle size of 3μm and keep warm for 5h, filter, wash, and dry in an oven at 100°C for 2h to obtain modified silica;

[0032] Step A2: 3 g of modified silica and 100 g of PET polyester chips are added into a twin-screw extruder, melt-mixed at 270° C., extruded, cooled, and pelletized to obtain matte masterbatch.

[0033] Example 2

[0034] This embodiment provides a matte masterbatch, which is prepared by the following steps:

[0035] Step A1, add 1.8g KH570 to 100mL 75wt% ethanol aqueous solution, stir and dissolve at 60°C, then add 8g silica with a central particle size of 4μm and keep warm for 4h, filter, wash, and dry in an oven at 100°C for 2h to obtain modified silica;

[0036] Step A2: 3.5 g of modified silica and 100 g of PET polyester chips are added into a twin-screw extruder, melt-mixed at 275° C., extruded, cooled, and pelletized to obtain matte masterbatch.

[0037] Example 3

[0038] This embodiment provides a matte masterbatch, which is prepared by the following steps:

[0039] Step A1, add 2g KH570 to 100mL 75wt% ethanol aqueous solution, stir and dissolve at 60°C, then add 8g silica with a particle size of 5μm and keep warm for 3h, filter, wash, and dry in an oven at 100°C for 2h to obtain modified silica;

[0040] Step A2: 4 g of modified silica and 100 g of PET polyester chips are added into a twin-screw extruder, melt-mixed at 280° C., extruded, cooled, and pelletized to obtain matte masterbatch.

[0041] Comparative Example 1

[0042] The difference between this comparative example and Example 2 is that in step A2, an equal amount of silicon dioxide with a particle size of 4 μm is used to replace the modified silicon dioxide, that is, the modification operation of step A1 is not performed, and the other raw materials and steps are the same.

[0043] Comparative Example 2

[0044] The difference between this comparative example and Example 2 is that in step A2, the amount of modified silicon dioxide is increased from 3.5 g to 5 g, that is, the modification operation of step A1 is not performed, and the other raw materials and steps are the same.

[0045] Example 4

[0046] This embodiment provides a nano-enhancer, which is prepared by the following steps:

[0047] 0.94 g of zirconium tetrachloride and 0.67 g of terephthalic acid were added to 60 mL of N, N-dimethylformamide, stirred and mixed evenly at room temperature, then stirred and reacted at 110° C. for 24 h, cooled to room temperature, washed with 70 mL of N, N-dimethylformamide and 70 mL of ethanol, centrifuged, and vacuum dried at 100° C. for 10 h to obtain a nano-enhancer.

[0048] Example 5

[0049] This embodiment provides a nano-enhancer, which is prepared by the following steps:

[0050] 1.06 g of zirconium tetrachloride and 0.76 g of terephthalic acid were added to 70 mL of N, N-dimethylformamide, stirred and mixed evenly at room temperature, then stirred and reacted at 120° C. for 24 h, cooled to room temperature, washed with 70 mL of N, N-dimethylformamide and 70 mL of ethanol, centrifuged, and vacuum dried at 100° C. for 10 h to obtain a nano-enhancer.

[0051] Example 6

[0052] This embodiment provides a nano-enhancer, which is prepared by the following steps:

[0053] 1.17 g of zirconium tetrachloride and 0.83 g of terephthalic acid were added to 80 mL of N, N-dimethylformamide, stirred and mixed evenly at room temperature, then stirred and reacted at 130° C. for 24 h, cooled to room temperature, washed with 70 mL of N, N-dimethylformamide and 70 mL of ethanol, centrifuged, and vacuum dried at 100° C. for 10 h to obtain a nano-enhancer.

[0054] Example 7

[0055] This embodiment provides a high-strength matte polyester film for car cover, which is prepared by the following preparation method:

[0056] Step S1, 7 parts by weight of PET polyester chips, 50 parts by weight of the matte masterbatch prepared in Example 1, 10 parts by weight of white non-fluorescent polyester chips containing 60 wt% of titanium dioxide with a particle size of 1.5 μm, and 0.8 parts by weight of the nano-enhancer prepared in Example 4 are stirred and mixed, pre-crystallized at 170° C., and dried at 155° C. for 4 h, and then transferred to an extruder, filtered through a filter at 275° C. to a die at 270° C., extruded to form a melt film, and the melt film is cooled on a cold drum at a temperature of 25° C. and a rotation speed of 43 m / min to form a thin film casting sheet;

[0057] Step S2, transferring the film cast into a biaxial stretching machine, and after a longitudinal stretching preheating section at 70°C, a longitudinal stretching shaping section at 27°C, and a transverse stretching shaping section at 235°C, stretching is performed to obtain a high-strength matte polyester film for car covers with a thickness of 50um.

[0058] Example 8

[0059] This embodiment provides a high-strength matte polyester film for car cover, which is prepared by the following preparation method:

[0060] Step S1, 7.5 parts by weight of PET polyester chips, 65 parts by weight of the matte masterbatch prepared in Example 2, 20 parts by weight of white non-fluorescent polyester chips containing 60 wt% of titanium dioxide with a particle size of 1.5 μm, and 0.9 parts by weight of the nano-enhancer prepared in Example 5 are stirred and mixed, pre-crystallized at 172° C., and dried at 155° C. for 4 h, and then transferred to an extruder, filtered through a filter at 275° C. to a die at 275° C., extruded to form a melt film, and the melt film is cooled on a cold drum at a temperature of 26° C. and a rotation speed of 43 m / min to form a thin film casting sheet;

[0061] Step S2, transferring the film cast into a biaxial stretching machine, and after a longitudinal stretching preheating section at 80°C, a longitudinal stretching shaping section at 30°C, and a transverse stretching shaping section at 238°C, stretching is performed to obtain a high-strength matte polyester film for car covers with a thickness of 50um.

[0062] Example 9

[0063] This embodiment provides a high-strength matte polyester film for car cover, which is prepared by the following preparation method:

[0064] Step S1, 8 parts by weight of PET polyester chips, 80 parts by weight of the matte masterbatch prepared in Example 3, 30 parts by weight of white non-fluorescent polyester chips containing 60 wt% of titanium dioxide with a particle size of 1.5 μm, and 1 part by weight of the nano-enhancer prepared in Example 6 are stirred and mixed, pre-crystallized at 175° C., and dried at 155° C. for 4 hours, and then transferred to an extruder, filtered through a filter at 275° C. to a die at 275° C., extruded to form a melt film, and the melt film is cooled on a cold drum at a temperature of 27° C. and a rotation speed of 43 m / min to form a thin film casting sheet;

[0065] Step S2, transferring the film cast into a biaxial stretching machine, and after going through a longitudinal stretching preheating section at 89°C, a longitudinal stretching shaping section at 35°C, and a transverse stretching shaping section at 240°C, stretching to obtain a high-strength matte polyester film for car covers with a thickness of 50um.

[0066] Comparative Example 3

[0067] The difference between this comparative example and Example 8 is that the matte masterbatch prepared in Comparative Example 1 is used to replace the matte masterbatch prepared in Example 2 in equal amount, and the other raw materials and steps are the same.

[0068] Comparative Example 4

[0069] The difference between this comparative example and Example 8 is that the matte masterbatch prepared in Comparative Example 2 is used to replace the matte masterbatch prepared in Example 2 in equal amount, and the other raw materials and steps are the same.

[0070] Comparative Example 5

[0071] The difference between this comparative example and Example 8 is that PET polyester chips are used in equal amounts to replace white non-fluorescent polyester chips containing 60 wt % of titanium dioxide with a particle size of 1.5 μm, and the other raw materials and steps are the same.

[0072] Comparative Example 6

[0073] This comparative example is different from Example 8 in that white non-fluorescent polyester chips containing 60 wt % of titanium dioxide with a particle size of 3 μm are used to replace white non-fluorescent polyester chips containing 60 wt % of titanium dioxide with a particle size of 1.5 μm, and the other raw materials and steps are the same.

[0074] Comparative Example 7

[0075] The difference between this comparative example and Example 8 is that the amount of the nano-enhancer prepared in Example 5 is adjusted from 0.9 parts by weight to 0 parts by weight, that is, no nano-enhancer is added, and the other raw materials and steps are the same.

[0076] Comparative Example 8

[0077] The difference between this comparative example and Example 8 is that the amount of the nano-enhancer prepared in Example 5 is increased from 0.9 parts by weight to 1.5 parts by weight, and the other raw materials and steps are the same.

[0078] Performance tests were performed on Examples 7 to 9 and Comparative Examples 3 to 8. The tensile strength, elastic modulus and elongation at break of the matte polyester film were tested according to GB / T1040.3; the haze of the matte polyester film was tested according to GB / T2410; and the gloss of the matte polyester film was tested according to GB / T 8807. The results are shown in Table 1.

[0079] Table 1

[0080]

[0081] It can be seen from the data in Table 1 that the matte polyester films prepared in Examples 7 to 9 have higher tensile strength and elongation at break, as well as higher haze and lower gloss; while the matte polyester films prepared in Comparative Examples 3 to 8 are inferior to those in Examples 7 to 9 in all properties, indicating that the matte polyester films prepared according to the formulation and preparation method of the present invention have improved mechanical properties and haze at the same time.

[0082] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0083] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A high-strength matte polyester film for car cover, characterized in that: It includes the following raw materials in parts by weight: 7-8 parts of PET polyester chips, 50-80 parts of matte masterbatch, 10-30 parts of white non-fluorescent polyester chips and 0.8-1 parts of nano-enhancer; the nano-enhancer is prepared by the following steps: Zirconium tetrachloride and terephthalic acid are added to N,N-dimethylformamide, stirred and mixed evenly at room temperature, then stirred and reacted at 110-130° C. for 24 hours, cooled to room temperature, washed, centrifuged, and vacuum dried to obtain a nano-enhancer.

2. The high-strength matte polyester film for car cover according to claim 1, characterized in that: The dosage ratio of the zirconium tetrachloride, terephthalic acid and N,N-dimethylformamide is 0.94-1.17 g: 0.67-0.83 g: 60-80 mL.

3. The high-strength matte polyester film for car cover according to claim 1, characterized in that: The matte masterbatch is prepared by the following steps: Step A1, adding a coupling agent to an ethanol aqueous solution, stirring and dissolving at 60° C., then adding silicon dioxide with a particle size of 3-5 μm and keeping the temperature for reaction for 3-5 hours, filtering, washing, and drying to obtain modified silicon dioxide; Step A2: adding modified silica and PET polyester chips into a twin-screw extruder for melt mixing, extruding, cooling, and pelletizing to obtain matte masterbatch.

4. The high-strength matte polyester film for car cover according to claim 3, characterized in that: The usage ratio of the coupling agent, silicon dioxide and ethanol aqueous solution is 1.5-2g:8g:100mL; the concentration of the ethanol aqueous solution is 75wt%.

5. The high-strength matte polyester film for car cover according to claim 3, characterized in that: The coupling agent is KH570.

6. The high-strength matte polyester film for car cover according to claim 3, characterized in that: The mass ratio of the modified silicon dioxide to the PET polyester chips is 3-4:

100.

7. The high-strength matte polyester film for car cover according to claim 1, characterized in that: The white non-fluorescent polyester chips are prepared by melt-mixing titanium dioxide with a particle size of 1.5 μm and PET polyester chips, and the content of the titanium dioxide is 60 wt %.

8. The method for preparing a high-strength matte polyester film for car cover according to claim 1, characterized in that: The following steps are involved: Step S1, mixing PET polyester chips, matte masterbatch, white non-fluorescent polyester chips and nano-enhancer in parts by weight of the formula, pre-crystallizing at 170-175° C., drying and transferring to an extruder, filtering through a filter to a die head to form a melt film, and cooling through a cold drum to form a film casting sheet; Step S2, transferring the film cast sheet into a biaxial stretching machine, and stretching the film through a longitudinal stretching preheating section, a longitudinal stretching shaping section, and a transverse stretching shaping section to obtain a high-strength matte polyester film for car covers.

9. The method for preparing a high-strength matte polyester film for car cover according to claim 8, characterized in that: The filter temperature is 275°C, the die head temperature is 270-275°C; the cold drum speed is 43m / min, and the cold drum temperature is 25-27°C.

10. The method for preparing a high-strength matte polyester film for car cover according to claim 8, characterized in that: The temperature of the longitudinal stretching preheating section is 70-89°C, the temperature of the longitudinal stretching shaping section is 27-35°C, and the temperature of the transverse stretching shaping section is 235-240°C.

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