PVC transparent car cover film and preparation method thereof

Abstract

The invention discloses a PVC transparent car cover film and a preparation method thereof, and relates to the field of PVC films. The PVC transparent car cover film is prepared from the following components in parts by weight: 60 to 75 parts of polyvinyl chloride resin, 18 to 30 parts of plasticizer, 1 to 5 parts of barium-zinc stabilizer, 3 to 5 parts of flexibilizer, 1 to 5 parts of polyvinylidene fluoride resin, 0.1 to 1 part of nanoparticle filler and 1 to 5 parts of assistant. By implementing the preparation method, the problem of abnormal whitening of the PVC transparent automobile cover film can be effectively solved.

Description

Technical Field

[0001] The invention relates to the field of PVC films, in particular to a PVC transparent car cover film and a preparation method thereof. Background Art

[0002] With the continuous development of society, the automobile industry has developed rapidly. During the normal use of cars, people usually apply film to the cars, commonly known as car film. Car film can provide good protection for the paint on the surface of the car, so the quality of the car film will directly affect the overall comfort and service life of the car. At present, the materials used for car stealth car film on the domestic market are generally divided into two categories: one is high-end TPU material, and the other is medium and low-end PVC material. Among them, the stealth car film made of PVC material is favored by more and more users because of its high quality and low price. At present, there is a common defect in the PVC transparent stealth car film on the market: after a period of use, some spots often appear, which greatly weakens the stealth performance of the stealth car film and affects the customer experience. Summary of the invention

[0003] Based on this, the purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a PVC transparent car cover film, which can prevent the generation of spots and optimize the stealth performance.

[0004] To achieve the above object, the technical solution adopted by the present invention is: a PVC transparent car cover film, which includes the following components in parts by weight:

[0005] 60 to 75 parts of polyvinyl chloride resin, 18 to 30 parts of plasticizer, 1 to 5 parts of barium zinc stabilizer, 3 to 5 parts of toughening agent, 1 to 5 parts of polyvinylidene fluoride resin, 0.1 to 1 part of nanoparticle filler, and 1 to 5 parts of auxiliary agent.

[0006] During the research on the problem of spots on PVC transparent car cover films, the inventors found that the main reasons for the problem are: 1. The existing formula of PVC transparent car cover films contains ingredients that are easily hydrated with water. In this way, the PVC and water will turn white due to hydration under long-term action, forming spots. 2. After the PVC transparent car cover film is pasted on the car surface, a closed environment is formed. If the operator leaves moisture on the car surface or there is moisture on the film surface glue layer during the film pasting process, the moisture enclosed in the film layer will vaporize under high temperature after pasting, but the vaporized water is difficult to overflow from the film, which causes the PVC material to turn white under the long-term action of water vapor. 3. PVC car cover films are prone to adhere to some impurities, such as gum, bird droppings and other impurities. Long-term adhesion and untimely cleaning will also form white spots.

[0007] Based on the profound understanding of the above reasons for the generation of white spots, the inventor first introduced polyvinylidene fluoride resin (PVDF) with strong hydrophobic effect into the PVC transparent car cover film, which can effectively improve the hydrophobic properties of the PVC transparent car cover film. On the one hand, the residual moisture before bonding is discharged as much as possible from the film layer before it is completely bonded and cured. On the other hand, after the surface is completely bonded and cured, it is less likely to adhere to water and water-containing stains, which greatly improves the defect of the PVC transparent car cover film turning white when exposed to water and forming white spots. In addition, PVDF can also reflect part of the ultraviolet rays irradiated to the surface of the PVC transparent car cover film, thereby improving the anti-ultraviolet performance. However, it should be noted that due to the high melting point and high crystallinity of PVDF, when it is introduced into the PVC system, there will be a relatively poor compatibility problem, and it is often necessary to increase the processing temperature to promote the compatibility of the two. The increase in processing temperature also means that the PVC component is easy to decompose. For this reason, the present invention introduces a barium zinc stabilizer into the formula, which can improve the overall high temperature stability of the formula and avoid the decomposition and discoloration of PVC at higher processing temperatures. In addition, the present invention also introduces nanoparticle fillers into the formula, which can form a fine rough surface on the film surface of the transparent car cover film. After the transparent car cover film is attached, the film layer has a certain air permeability, so that the water vapor sandwiched between the film layer and the car body can overflow after being vaporized at high temperature, reducing the whitening abnormality.

[0008] The amount of polyvinyl chloride resin is 60 to 75 parts, exemplarily 62, 64, 66, 68, 70, 72 or 74 parts, but not limited thereto, preferably 65 to 75 parts.

[0009] Wherein, the plasticizer can be a phthalate plasticizer, a phosphate plasticizer or a polyester plasticizer commonly used in the art, exemplified by dioctyl phthalate (DOP), dibutyl phthalate (DBP), and tricresyl phosphate, but not limited thereto. The plasticizer can reduce the glass transition temperature and flow temperature of PVC, improve plasticity, and can also effectively improve the compatibility of PVC and PVDF. Specifically, the amount of the plasticizer is 18 to 30 parts, exemplified by 19 parts, 21 parts, 23 parts, 25 parts, 27 parts or 29 parts, but not limited thereto. Preferably, the amount of the plasticizer is 20 to 30 parts.

[0010] The amount of the barium zinc stabilizer is 1 to 5 parts, exemplarily 1.5, 2, 2.5, 3, 3.5, 4 or 4.5 parts, but not limited thereto, preferably 1.5 to 3 parts.

[0011] Among them, the toughening agent can be selected from chlorinated polyethylene or ACR commonly used in the art, but is not limited thereto. The toughening agent can improve the low-temperature toughness of the PVC transparent car cover film. The amount of the toughening agent is 3 to 5 parts, exemplarily 3.4 parts, 3.8 parts, 4.2 parts, 4.6 parts or 4.8 parts, but is not limited thereto. Preferably, it is 4 to 5 parts.

[0012] The amount of polyvinylidene fluoride is 1 to 5 parts, and is exemplarily 1.5, 2, 2.5, 3, 3.5, 4 or 4.5 parts, preferably 1 to 4 parts.

[0013] The amount of the nanoparticle filler is 0.1 to 1 part, exemplarily 0.2, 0.3, 0.4, 0.5, 0.7 or 0.9, but not limited thereto, preferably 0.2 to 0.5.

[0014] Preferably, in one embodiment of the present invention, the plasticizers are dioctyl phthalate (DOP) and polyester plasticizers. First, the combination of the above two plasticizers can further optimize the compatibility of PVC and PVDF, increase the amount of PVDF used, and further optimize the hydrophobic properties of the transparent car cover film. Second, since the transparent car cover film needs to be attached to the surface of various colored cars, when attached to the surface of certain dark-colored cars, the outer body can reach 65°C to 70°C after exposure to the sun. At this temperature for a long time, DOP will precipitate, and the introduction of polyester plasticizers can stabilize DOP. However, since polyester plasticizers are prone to agglomeration during processing, the processing efficiency will be reduced. Therefore, the combination of the two can also improve production efficiency. Specifically, in order to simultaneously ensure the stability, hydrophobicity and processing efficiency of the transparent car cover film, the weight ratio of DOP to polyester plasticizer is controlled to be 8-15:10-15; exemplary ratios are 8:11, 9:13, 10:10, 11:12, 13:14 or 15:13, but not limited thereto. More preferably, the usage ratio of DOP to polyester plasticizer is 1:1.

[0015] Among them, the molecular weight (number average molecular weight) of the polyester plasticizer is 2000 to 5000, and the polyester plasticizer in this molecular weight range has a higher plasticizing efficiency.

[0016] Preferably, in one embodiment of the present invention, the melt index of the polyvinylidene fluoride resin is 0.2g / 10min to 2.0g / 10min. The test conditions of the melt index are 230°C and the load is 0.325kg. PVDF with the above melt index can effectively improve the processing performance and improve the compatibility with PVC. In addition, the water absorption rate of polyvinylidene fluoride at 100°C is controlled to be ≤0.05%, which can further optimize the hydrophobic properties of PVC transparent car cover film. Among them, the method for determining the water absorption rate is: put the sample into an oven at 50°C, dry it for 24 hours, and then cool it to room temperature in a dryer, weigh each sample, accurate to 1mg, and count it as m1. Place the sample in a container filled with distilled water and control the water temperature at 23°C. After soaking for 24 hours, take out the sample and quickly wipe off the water on the surface of the sample with a clean dry cloth or filter paper. Weigh each sample again to an accuracy of 1 mg, recorded as m2, then the water absorption rate = (m2-m1) / m1×100%, and take the average of at least three measured values ​​as the final value.

[0017] Preferably, in one embodiment of the present invention, the degree of polymerization of the polyvinyl chloride resin is 1000-1500. PVC with a higher degree of polymerization can improve the tensile properties, heat resistance and aging resistance of the transparent car cover film. It is also more compatible with PVDF and has better compatibility.

[0018] Preferably, in one embodiment of the present invention, the toughening agent is ARC (core-shell acrylic resin), and the rubber content thereof is 30wt%-35wt%. The toughening agent can better improve the low-temperature toughness.

[0019] Preferably, in one embodiment, the nanoparticle filler is nano-silicon dioxide, which has little effect on the transparency of the transparent car cover film and can improve the temperature resistance of the transparent car cover film.

[0020] The auxiliary agent may be a common colorant, mildewproofing agent, flame retardant, etc. in the art, but is not limited thereto. Preferably, in one embodiment, the auxiliary agent includes the following components in parts by weight:

[0021] 0.5 to 1.5 parts of UV absorber, 0.5 to 1 part of antioxidant, 0.02 to 0.1 part of masterbatch. Among them, UV absorber can reduce the damage of UV to the molecular structure of the product and improve the light aging performance, while antioxidant can enhance the resistance to infrared rays.

[0022] More specifically, the ultraviolet absorber is UV-531, and the antioxidant is antioxidant 1076. The ultraviolet absorber and antioxidant are both liquids, have good compatibility with the system, and have low precipitation risk.

[0023] Correspondingly, the present invention also discloses a method for preparing a PVC car cover film, which is used to prepare the above-mentioned PVC car cover film, and comprises:

[0024] (1) mixing the components to obtain a mixture;

[0025] (2) kneading the mixed material at 140° C. to 150° C. to obtain a mixed material;

[0026] (3) The mixed material is calendered and cooled to obtain a PVC transparent car cover film.

[0027] Preferably, in one embodiment of the present invention, step (1) comprises:

[0028] (1.1) Mixing the components at 90°C to 100°C for 400s to 600s to obtain a high-temperature mixture;

[0029] (1.2) The high-temperature mixture is mixed at 50° C. to 70° C. for 350 seconds to 450 seconds to obtain a mixture.

[0030] Preferably, in one embodiment of the present invention, step (3) comprises:

[0031] (3.1) The mixed material is calendered by a five-roll calender to obtain a preliminary film; wherein the temperature of roller No. 1 is 190°C to 203°C, the temperature of roller No. 2 is 200°C to 210°C, the temperature of roller No. 3 is 190°C to 200°C, the temperature of roller No. 4 is 185°C to 200°C, and the temperature of roller No. 5 is 180°C to 190°C;

[0032] (3.2) supercooling the preliminary film with water to obtain an intermediate film; wherein the temperature of the cooling water is 40° C. to 55° C.;

[0033] (3.3) The moisture on the middle film is dried to obtain a PVC transparent car cover film.

[0034] The implementation of the present invention has the following beneficial effects:

[0035] The PVC transparent car cover film of the present invention introduces a polyvinylidene fluoride resin (PVDF) with a strong hydrophobic effect, which improves the hydrophobic performance of the PVC transparent car cover film. On the one hand, the residual moisture before bonding is discharged from the film layer as much as possible before the film is completely bonded and cured. On the other hand, after the film is completely bonded and cured, it is less likely to adhere to water and water-containing stains on the surface, which greatly improves the defect of the PVC transparent car cover film turning white when exposed to water and forming white spots. In addition, the present invention also introduces a nanoparticle filler into the formula, which can form a fine rough surface on the film surface of the transparent car cover film. After the transparent car cover film is bonded, the film layer has a certain air permeability, so that the water vapor sandwiched between the film layer and the car body can overflow after high-temperature vaporization, reducing the whitening abnormality. DETAILED DESCRIPTION

[0036] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0037] In the examples, the experimental methods used are conventional methods unless otherwise specified, and the materials, reagents, etc. used are all commercially available unless otherwise specified.

[0038] The raw materials used in the embodiments and comparative examples are described below, but are not limited to these materials:

[0039] A1: PVC resin, degree of polymerization 1500; S75, Formosa Plastics;

[0040] A2: PVC resin, degree of polymerization 800; S60, Formosa Plastics;

[0041] B1: Plasticizer: DOP, commercially available;

[0042] B2: polyester plasticizer, molecular weight 3000, W-2370, DIC Corporation;

[0043] B3: polyester plasticizer, molecular weight 5000, W-2640s, DIC Corporation;

[0044] C1: Barium zinc stabilizer: BZ-424PF, Nantong Aidewang Chemical Co., Ltd.;

[0045] C2: Calcium zinc solid stabilizer: 368F, Guangdong Sendeli Environmental Protection New Material Technology Co., Ltd.;

[0046] D: Toughener: ARC, HIA80, rubber content 30wt%, Dow Chemical;

[0047] E1: PVDF resin: melt index is 1.5g / 10min, water absorption is 0.03%, 761A, Arkema;

[0048] E2: PVDF resin: melt index is 2.5g / 10min, water absorption is 0.06%, 2750, Arkema

[0049] F1: Nanoparticle filler: nano calcium carbonate, commercially available;

[0050] F2: Nanoparticle filler: nanosilica, S820, Bohuasi Nanotechnology (Ningbo) Co., Ltd.;

[0051] G: UV absorber: UV-531, BASF;

[0052] H: Antioxidant: Antioxidant 1076, commercially available;

[0053] I: Masterbatch: commercially available.

[0054] Example 1 to Example 8 and Comparative Example 1 to Comparative Example 6

[0055] The components and weight proportions of the PVC transparent car cover films of Examples 1 to 8 and Comparative Examples 1 to 6 are shown in Table 1 and Table 2, and the preparation method thereof is as follows:

[0056] (1) Mixing the components at 90° C. for 480 seconds to obtain a high-temperature mixture;

[0057] (2) The high-temperature mixture is mixed at 50° C. for 400 seconds to obtain a mixture.

[0058] (3) kneading the mixture at 150° C. to obtain a mixed material;

[0059] (4) calendering the mixed material using a five-roll calender to obtain a preliminary film; wherein the temperature of roller No. 1 is 200° C., the temperature of roller No. 2 is 202° C., the temperature of roller No. 3 is 198° C., the temperature of roller No. 4 is 196° C., and the temperature of roller No. 5 is 189° C.;

[0060] (5) cooling the preliminary film with water to obtain an intermediate film; wherein the temperature of the cooling water is 40° C. to 50° C.;

[0061] (6) The moisture on the middle film is dried, the edges are cut, and the film is rolled into a roll to obtain a transparent PVC car cover film.

[0062] Table 1

[0063]

[0064] Table 2

[0065]

[0066] The PVC transparent car cover films of Examples 1 to 8 and Comparative Examples 1 to 6 were tested, and the specific method is as follows:

[0067] (1) Internal moisture white spots: Take an aluminum alloy sheet (100 mm × 100 mm), spray it with common car body paint, wipe it with a damp cloth, and apply a transparent PVC car film before it is completely dry; place it at 50°C to 60°C for 20 days and observe the white spots;

[0068] (2) White spots caused by external moisture contamination: Take an aluminum alloy sheet (100 mm × 100 mm), spray it with common car body paint, wipe it with a damp cloth, dry it until it is absolutely dry, cool it to room temperature, apply a PVC transparent car cover film, soak it in water at a temperature of 20℃ to 25℃, leave it for 10 days, and observe the white spots.

[0069] (3) Weather resistance: measured according to ISO 105-B02-2013 method, the measurement time is 1000 hours, and the color difference value △E is measured;

[0070] (4) Tensile strength and tensile elongation shall be measured according to the method of GB / T 13022-1991.

[0071] The specific test results are shown in Table 3 and Table 4:

[0072] Table 3

[0073]

[0074] Table 4

[0075]

[0076] From the comparison between Example 1 and Comparative Examples 1 to 6, it can be seen that when the formulation system of the present invention is changed, white spots are easily generated.

[0077] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A PVC transparent car cover film, characterized in that: The composition comprises the following components in parts by weight: 60 to 75 parts of polyvinyl chloride resin, 18 to 30 parts of plasticizer, 1 to 5 parts of barium zinc stabilizer, 3 to 5 parts of toughening agent, 1 to 5 parts of polyvinylidene fluoride resin, 0.1 to 1 part of nanoparticle filler, and 1 to 5 parts of auxiliary agent.

2. The transparent PVC car cover film according to claim 1, characterized in that: The plasticizer includes dioctyl phthalate and polyester plasticizer; The weight ratio of dioctyl phthalate to polyester plasticizer is 8-15:10-15; The molecular weight of the polyester plasticizer is 2000-5000.

3. The PVC transparent car cover film according to claim 2, characterized in that: The melt index of the polyvinylidene fluoride resin is 0.2 g / 10 min to 2.0 g / 10 min; The water absorption rate of the polyvinylidene fluoride at 100° C. is ≤0.05%.

4. The transparent PVC car cover film according to claim 3, characterized in that: The degree of polymerization of the polyvinyl chloride resin is 1000 to 1500; and / or The barium zinc stabilizer is a powder type stabilizer.

5. The PVC transparent car cover film according to claim 1, characterized in that: The toughening agent is a core-shell acrylic resin, and the rubber content thereof is 30wt%-35wt%; and / or The nano-particle filler is nano-silicon dioxide.

6. The PVC transparent car cover film according to claim 1, characterized in that: The auxiliary agent comprises the following components in parts by weight: 0.5 to 1.5 parts of ultraviolet absorber, 0.5 to 1 part of antioxidant, 0.02 to 0.1 part of masterbatch.

7. The transparent PVC car cover film according to claim 6, characterized in that: The antioxidant is antioxidant 1076; and / or The ultraviolet absorber is UV-531.

8. A method for preparing a PVC transparent car cover film, used for preparing the PVC transparent car cover film according to any one of claims 1 to 7, characterized in that: include: (1) mixing the components to obtain a mixture; (2) kneading the mixed material at 140° C. to 150° C. to obtain a mixed material; (3) The mixed material is calendered and cooled to obtain a PVC transparent car cover film.

9. The method for preparing a transparent PVC car cover film according to claim 8, characterized in that: Step (1) comprises: (1.1) Mixing the components at 90°C to 100°C for 400s to 600s to obtain a high-temperature mixture; (1.2) The high-temperature mixture is mixed at 50° C. to 70° C. for 350 seconds to 450 seconds to obtain a mixture.

10. The method for preparing a transparent PVC car cover film according to claim 8, characterized in that: Step (3) includes: (3.1) The mixed material is calendered by a five-roll calender to obtain a preliminary film; wherein the temperature of roller No. 1 is 190°C to 203°C, the temperature of roller No. 2 is 200°C to 210°C, the temperature of roller No. 3 is 190°C to 200°C, the temperature of roller No. 4 is 185°C to 200°C, and the temperature of roller No. 5 is 180°C to 190°C; (3.2) supercooling the preliminary film with water to obtain an intermediate film; wherein the temperature of the cooling water is 40° C. to 55° C.; (3.3) The moisture on the middle film is dried to obtain a PVC transparent car cover film.

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