A high-adhesion colorful pearlescent film and its preparation method

Abstract

The present invention relates to the technical field of composite film materials, and more specifically to a high-adhesion colorful pearlescent film and a preparation method thereof. The colorful pearlescent film uses PP as a resin matrix and comprises a three-layer structure, namely, a first protective layer, a pearlescent layer, and a second protective layer. High adhesion is achieved by coating one side of the pearlescent film with a high-adhesion pressure-sensitive adhesive. The pearlescent layer, due to the addition of an organic pearlescent pigment, can achieve a colorful pearlescent visual effect. Under the action of a modifier, the pearlescent pigment is combined with an organic reactive dye to produce an organic pearlescent pigment, which not only promotes compatibility between the pearlescent pigment and the resin matrix, but also has excellent ultraviolet shielding properties, thereby improving the photostability of the colorful pearlescent film.

Description

Technical Field

[0001] The present invention relates to the technical field of composite film materials, and in particular to a high-adhesion colorful pearlescent film and a preparation method thereof. Background Art

[0002] Car film changes the color of the car by applying a colored film to the car body without changing the original paint. This not only changes the vehicle's exterior color, but also isolates the paint from the air, preventing aging, oxidation, and scratches. For some young car owners, applying colorful pearlescent film is more popular to achieve the goal of pursuing fashion trends.

[0003] Colorful pearlescent films are generally produced by using pearlescent pigments, which utilize the interference of light to produce a beautiful pearlescent luster. Colorful pearlescent pigments are prepared by adding metal ions with color, such as iron and chromium. However, the color variety of metal ions is limited, while organic reactive dyes are brightly colored, with a wide variety of colors and a wider range of options. Organic pearlescent pigments are mica titanium pearlescent pigments colored with organic dyes. The mixing of mica titanium pearlescent pigments and organic dyes can impart color and pearlescent luster to the matrix. However, the photostability of organic reactive dyes is poor and they are prone to fading under illumination conditions, reducing the aesthetics of the film. Chinese patent CN109836852B discloses a method for preparing a red aluminum flake pigment. The method uses an inorganic oxide to encapsulate an organic red pigment to improve the photostability of the organic pigment. The oxide and the organic pigment core-shell structure complex are then complexed with aluminum flakes to obtain a stable red pearlescent pigment. However, when the red pearlescent pigment is used to prepare a film material by blending with a polymer, there is a problem of poor compatibility with the polymer material, which affects performance. Summary of the Invention

[0004] In view of the deficiencies of the prior art, the present invention provides a high-adhesion colorful pearlescent film to solve the problems in the prior art of improving the compatibility between organic pearlescent pigments and polymer materials and the light stability of organic reactive dyes.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0006] A method for preparing a high-adhesion colorful pearlescent film comprises the following steps:

[0007] Step 1: Prepare a modifier using styrene, acryloyloxyethyltrimethylammonium chloride, maleic acid, and 4-propyleneoxy-2-hydroxybenzophenone as monomers;

[0008] Step 2: reacting the modifier with the pearlescent pigment to prepare a modified pearlescent pigment;

[0009] Step 3: reacting the modified pearlescent pigment with an organic reactive dye to prepare an organic pearlescent pigment;

[0010] Step 4: PP (polypropylene resin) is mixed with organic pearlescent pigment as raw materials for the pearlescent layer, and melted to obtain a pearlescent layer melt;

[0011] PP is used as the raw material for the first protective layer and the raw material for the second protective layer, respectively, and melted to obtain a first protective layer melt and a second protective layer melt;

[0012] The first protective layer melt, the pearlescent layer melt, and the second protective layer melt are combined and extruded in a die head, and cooled to obtain a film;

[0013] The film is biaxially stretched to obtain a colorful pearlescent film;

[0014] The colorful pearlescent film comprises a three-layer structure, which is a first protective layer, a pearlescent layer, and a second protective layer in sequence;

[0015] Step 5: Apply high-adhesion pressure-sensitive adhesive on one side of the pearlescent film, cure it, and cover it with a release film to obtain a high-adhesion colorful pearlescent film.

[0016] Preferably, in step 1, preparing the modifier specifically comprises:

[0017] Mixing monomers of styrene, acryloyloxyethyltrimethylammonium chloride, maleic acid, 4-propyleneoxy-2-hydroxybenzophenone, an initiator, and 1-dodecyl mercaptan to obtain a mixed solution;

[0018] After heating acetone to a set temperature, the mixed solution is added dropwise under nitrogen protection, and after the addition is complete, the mixture is reacted. After the reaction is complete, the mixture is precipitated, filtered, and dried to obtain a modifier;

[0019] The molar ratio of styrene, acryloyloxyethyltrimethylammonium chloride, maleic acid, and 4-propyleneoxy-2-hydroxybenzophenone is (6-8):(3-5):(3-5):(4-6), the amount of the initiator added is 0.6%-1% of the total mass of the monomers, the amount of 1-dodecyl mercaptan added is 0.1%-0.3% of the total mass of the monomers, the amount of acetone used is 150-250 times the total mass of the monomers, the dropwise addition time of the mixed solution is 2-3 hours, and the reaction conditions are to keep the reaction under reflux at the set temperature for 1-3 hours;

[0020] The set temperature is 70-90°C.

[0021] Preferably, the initiator comprises azobisisobutyronitrile.

[0022] Preferably, in step 2, preparing the modified pearlescent pigment specifically comprises:

[0023] Adding pearlescent pigment into acetone and performing ultrasonic dispersion to obtain pearlescent pigment dispersion;

[0024] dissolving the modifier in acetone to obtain a modifier solution;

[0025] adding a modifier solution to the pearlescent pigment dispersion, reacting, and after the reaction is completed, centrifuging, washing, and drying to obtain a modified pearlescent pigment;

[0026] The mass ratio of pearlescent pigment to modifier is 100:(20-30), the mass ratio of pearlescent pigment to acetone in the pearlescent pigment dispersion is 100:(600-800), the mass ratio of modifier to acetone in the modifier solution is (20-30):(300-500), and the reaction conditions are 75-95°C for 18-36h.

[0027] Preferably, the pearlescent pigment comprises mica titanium pearlescent pigment.

[0028] Preferably, in step 3, preparing the organic pearlescent pigment specifically includes:

[0029] The organic active dye is dissolved in deionized water, and the modified pearlescent pigment is added thereto, and ultrasonic treatment is performed. After the ultrasonic treatment is completed, the organic pearlescent pigment is dried to obtain the organic pearlescent pigment.

[0030] The mass ratio of the organic active dye, deionized water and modified pearlescent pigment is (3-5):(60-80):10, and the ultrasonication condition is 40-80 kHz frequency for 1-2 hours.

[0031] Preferably, in the step 4, when preparing the pearlescent layer melt, the mass ratio of PP to organic pearlescent pigment is 100:(4-8), and the melting temperature is 220-240°C;

[0032] When preparing the first protective layer melt and the second protective layer melt, the melting temperature is 220-240°C;

[0033] The extrusion temperature is 240-260°C;

[0034] The biaxial stretching process includes longitudinal stretching, transverse stretching and shaping;

[0035] The longitudinal stretching includes: preheating at a temperature of 105-115°C, longitudinal stretching at a temperature of 80-100°C, and a stretching ratio of 300-500%;

[0036] Transverse stretching includes: preheating at a temperature of 160-180°C, transverse stretching at a temperature of 150-170°C, and a stretching ratio of 600-800%;

[0037] The setting temperature is 160-170℃.

[0038] Preferably, in step 5, the coating amount of the high adhesion pressure sensitive adhesive is 30-50 g / m2 The curing conditions are curing at 110-120℃ for 1-2 minutes.

[0039] The high-adhesion pressure-sensitive adhesive in step 5 is prepared by the following steps:

[0040] S1, mixing butyl acrylate, isooctyl acrylate, methyl methacrylate, 2-(perfluorobutyl)ethyl acrylate, glycidyl methacrylate, hydroxyethyl acrylate, ethyl acetate, and azobisisobutyronitrile to obtain a reaction solution;

[0041] dividing the reaction liquid into a first part of the reaction liquid and a second part of the reaction liquid;

[0042] S2, heating the first part of the reaction liquid for reaction, adding the second part of the reaction liquid dropwise after the addition is complete, continuing the reaction, cooling after the reaction is complete, adding a crosslinking agent and a tackifying agent to obtain a high-adhesion pressure-sensitive adhesive;

[0043] Among them, the mass ratio of butyl acrylate, isooctyl acrylate, methyl methacrylate, 2-(perfluorobutyl)ethyl acrylate, glycidyl methacrylate, hydroxyethyl acrylate, ethyl acetate, azobisisobutyronitrile, crosslinking agent and viscosity-increasing agent is (50-60):(65-75):(60-80):(30-50):(40-60):(20-30):(250-350):(5-10):(10-20):(20-30), the heating reaction condition is reflux reaction at a temperature of 70-90°C for 1-2h, and the continued reaction condition is reflux reaction at a temperature of 70-80°C for 3-5h.

[0044] Preferably, the cross-linking agent comprises hexamethylene diisocyanate;

[0045] The tackifying aid includes abietic acid.

[0046] A high-adhesion colorful pearlescent film is prepared by the above-mentioned method for preparing a high-adhesion colorful pearlescent film.

[0047] Compared with the prior art, the present invention has the following beneficial effects:

[0048] The colorful pearlescent film of the present invention uses PP as a resin matrix and is prepared by a biaxial stretching process. It comprises a three-layer structure consisting of a first protective layer, a pearlescent layer, and a second protective layer. The first protective layer and the second protective layer protect the pearlescent layer. The pearlescent layer is added with organic pearlescent pigments to achieve a colorful pearlescent visual effect. The colorful pearlescent film is coated with a high-adhesion pressure-sensitive adhesive on one side of the pearlescent film to impart high adhesion.

[0049] The organic pearlescent pigment of the present invention comprises a pearlescent pigment and an organic reactive dye. The pearlescent pigment is modified with a modifier, which not only improves the dispersion uniformity between the pearlescent pigment and the resin matrix, but also improves the binding force between the pearlescent pigment and the organic reactive dye and improves the light stability of the organic reactive dye.

[0050] In preparing the modifier, styrene, acryloyloxyethyltrimethylammonium chloride, maleic acid, and 4-propyleneoxy-2-hydroxybenzophenone are used as monomers. The molecular chain formed by polymerization between the vinyl groups serves as a solvation chain, which not only improves compatibility with PP but also creates a steric stabilizing effect. The carboxyl group introduced into the maleic acid monomer acts as an anchoring group. The electronegativity difference between the carboxyl group and the hydroxyl group on the surface of the pearlescent pigment is small, resulting in a strong surface interaction with the pearlescent pigment. Under the synergistic effect of steric hindrance, the pearlescent pigment has good dispersion in PP. The cationic group (quaternary ammonium salt) introduced into the acryloyloxyethyltrimethylammonium chloride monomer can combine with the anionic groups (carboxyl group, sulfonic acid group, etc.) in the organic active dye molecule to achieve bonding between the pearlescent pigment and the organic active dye. The hydroxybenzophenone group introduced into the 4-propyleneoxy-2-hydroxybenzophenone monomer acts as a light stabilizer, effectively absorbing ultraviolet light and reducing the fading of the organic active dye caused by the interaction of ultraviolet light with the organic active dye.

[0051] The high-adhesion pressure-sensitive adhesive of the present invention is prepared from butyl acrylate, isooctyl acrylate, methyl methacrylate, 2-(perfluorobutyl)ethyl acrylate, glycidyl methacrylate and hydroxyethyl acrylate as monomers and has high adhesion and good waterproofness. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 Schematic diagram of the preparation of the modifier in the present invention;

[0053] Figure 2 This is a line graph showing the light stability test results of the high-adhesion colorful pearlescent films prepared in Examples 1-4 of the present invention and Comparative Examples 1-2. DETAILED DESCRIPTION

[0054] Example 1: This example discloses a method for preparing a high-adhesion colorful pearlescent film, comprising the following steps:

[0055] Step 1: Mixing monomers of styrene, acryloyloxyethyltrimethylammonium chloride, maleic acid, 4-propyleneoxy-2-hydroxybenzophenone, azobisisobutyronitrile, and 1-dodecylmercaptan to obtain a mixed solution;

[0056] The molar ratio of styrene, acryloyloxyethyltrimethylammonium chloride, maleic acid and 4-propyleneoxy-2-hydroxybenzophenone is 6:3:3:4, the amount of azobisisobutyronitrile added is 0.6% of the total weight of the monomers, and the amount of 1-dodecyl mercaptan added is 0.1% of the total weight of the monomers;

[0057] After heating acetone to a set temperature, the amount of acetone used is 150 times the mass of the monomers, and the mixed solution is added dropwise under nitrogen protection for 2 hours. After the addition is completed, the mixture is kept refluxed at 70°C for 3 hours. After the reaction is completed, ethanol 5 times the mass of acetone is added for precipitation, filtered, and the precipitate is placed in a vacuum drying oven at 50°C for 24 hours to obtain a modifier;

[0058] Step 2: adding mica titanium pearlescent pigment to acetone at a mass ratio of mica titanium pearlescent pigment to acetone of 100:600, and ultrasonically dispersing the mica titanium pearlescent pigment at a frequency of 50 kHz for 30 minutes to obtain a pearlescent pigment dispersion;

[0059] Dissolving the modifier in acetone at a mass ratio of the modifier to acetone of 20:300 to obtain a modifier solution;

[0060] Adding a modifier solution to a pearlescent pigment dispersion, wherein the mass ratio of the pearlescent pigment in the pearlescent pigment dispersion to the modifier in the modifier solution is 100:20, reacting at 75° C. for 36 hours, and after the reaction, centrifugally washing with acetone three times, and drying in a vacuum drying oven at 50° C. for 24 hours to obtain a modified pearlescent pigment;

[0061] Step 3: dissolving the organic active dye in deionized water, adding the modified pearlescent pigment, and ultrasonicating at a frequency of 40 kHz for 2 h. After the ultrasonication is completed, the mixture is placed in a vacuum drying oven at 80° C. and dried to a constant weight to obtain the organic pearlescent pigment;

[0062] Among them, the mass ratio of organic reactive dye, deionized water and modified pearlescent pigment is 3:60:10;

[0063] Step 4: PP and organic pearlescent pigment are mixed in a mass ratio of 100:4, and the mixture is melted at a melting temperature of 220° C. to obtain a pearlescent layer melt;

[0064] PP is used as the raw material for the first protective layer and the raw material for the second protective layer, respectively, and melted at a melting temperature of 220°C to obtain a first protective layer melt and a second protective layer melt;

[0065] The first protective layer melt, the pearlescent layer melt, and the second protective layer melt are combined and extruded in a die head at an extrusion temperature of 240°C and cooled on a cooling roller to obtain a film;

[0066] The film is stretched longitudinally, stretched transversely and shaped to obtain a colorful pearlescent film;

[0067] The longitudinal stretching includes: preheating at 110°C, longitudinal stretching at 90°C, and a stretching ratio of 400%.

[0068] Transverse stretching includes: preheating at 170°C, transverse stretching at 160°C, and a stretching ratio of 700%;

[0069] The setting temperature is 165℃;

[0070] The colorful pearlescent film comprises a three-layer structure, which is a first protective layer, a pearlescent layer, and a second protective layer in sequence;

[0071] The thicknesses of the first protective layer, pearlescent layer, and second protective layer are 40 μm, 35 μm, and 40 μm, respectively;

[0072] Step 5: Apply high adhesion pressure sensitive adhesive on one side of the pearlescent film. The coating amount of high adhesion pressure sensitive adhesive is 40g / m 2 , curing at 115℃ for 1.5min, and covering with PET release film to obtain a colorful pearlescent film with high adhesion;

[0073] The high-adhesion pressure-sensitive adhesive is prepared by the following steps:

[0074] S1, mixing butyl acrylate, isooctyl acrylate, methyl methacrylate, 2-(perfluorobutyl)ethyl acrylate, glycidyl methacrylate, hydroxyethyl acrylate, ethyl acetate, and azobisisobutyronitrile to obtain a reaction solution;

[0075] The reaction liquid is divided into a first part of the reaction liquid and a second part of the reaction liquid, wherein the first part of the reaction liquid and the second part of the reaction liquid have the same mass;

[0076] S2. The first portion of the reaction liquid was subjected to a heating reaction, wherein the heating reaction conditions were a reflux reaction at 80° C. for 1.5 hours. After the reaction was completed, the second portion of the reaction liquid was added dropwise for 2 hours. After the addition was completed, the reaction was continued under a reflux reaction at 75° C. for 4 hours. After the reaction was completed, the reaction was cooled, and hexamethylene diisocyanate and rosin acid were added to obtain a high-adhesion pressure-sensitive adhesive;

[0077] Among them, the mass ratio of butyl acrylate, isooctyl acrylate, methyl methacrylate, 2-(perfluorobutyl)ethyl acrylate, glycidyl methacrylate, hydroxyethyl acrylate, ethyl acetate, azobisisobutyronitrile, hexamethylene diisocyanate and rosin acid is 55:70:70:40:50:25:300:7:15:25.

[0078] Example 2: This example discloses a method for preparing a high-adhesion colorful pearlescent film, comprising the following steps:

[0079] Step 1: Mixing monomers of styrene, acryloyloxyethyltrimethylammonium chloride, maleic acid, 4-propyleneoxy-2-hydroxybenzophenone, azobisisobutyronitrile, and 1-dodecylmercaptan to obtain a mixed solution;

[0080] The molar ratio of styrene, acryloyloxyethyltrimethylammonium chloride, maleic acid and 4-propyleneoxy-2-hydroxybenzophenone is 8:5:5:6, the amount of azobisisobutyronitrile added is 1% of the total weight of the monomers, and the amount of 1-dodecyl mercaptan added is 0.3% of the total weight of the monomers;

[0081] After heating acetone to a set temperature, the amount of acetone used is 250 times the mass of the monomers, and the mixed solution is added dropwise under nitrogen protection for 3 hours. After the addition is completed, the mixture is kept refluxed at 90°C for 1 hour. After the reaction is completed, ethanol 5 times the mass of acetone is added for precipitation, filtered, and the precipitate is placed in a vacuum drying oven at 50°C for 24 hours to obtain a modifier;

[0082] Step 2: adding mica titanium pearlescent pigment to acetone at a mass ratio of mica titanium pearlescent pigment to acetone of 100:800, and ultrasonically dispersing the mica titanium pearlescent pigment at a frequency of 50 kHz for 30 minutes to obtain a pearlescent pigment dispersion;

[0083] The modifier is dissolved in acetone at a mass ratio of the modifier to acetone of 30:500 to obtain a modifier solution;

[0084] Adding a modifier solution to a pearlescent pigment dispersion, wherein the mass ratio of the pearlescent pigment in the pearlescent pigment dispersion to the modifier in the modifier solution is 100:30, reacting at 95° C. for 18 hours, and after the reaction, centrifugally washing with acetone three times, and drying in a vacuum drying oven at 50° C. for 24 hours to obtain a modified pearlescent pigment;

[0085] Step 3: dissolving the organic active dye in deionized water, adding the modified pearlescent pigment, and ultrasonicating at a frequency of 80 kHz for 1 hour. After the ultrasonication is completed, the mixture is placed in a vacuum drying oven at 80° C. and dried to a constant weight to obtain an organic pearlescent pigment;

[0086] Among them, the mass ratio of organic reactive dye, deionized water and modified pearlescent pigment is 5:80:10;

[0087] Step 4: PP and organic pearlescent pigment are mixed in a mass ratio of 100:8, and the mixture is melted at a melting temperature of 240° C. to obtain a pearlescent layer melt;

[0088] PP is used as the raw material for the first protective layer and the raw material for the second protective layer, respectively, and melted at a melting temperature of 240°C to obtain a first protective layer melt and a second protective layer melt;

[0089] The first protective layer melt, the pearlescent layer melt, and the second protective layer melt are combined and extruded in a die head at an extrusion temperature of 260°C and cooled on a cooling roller to obtain a film;

[0090] The film is stretched longitudinally, stretched transversely and shaped to obtain a colorful pearlescent film;

[0091] The process parameters for longitudinal stretching, transverse stretching and shaping are the same as those in Example 1;

[0092] The colorful pearlescent film comprises a three-layer structure, which is a first protective layer, a pearlescent layer, and a second protective layer in sequence;

[0093] The thicknesses of the first protective layer, pearlescent layer, and second protective layer are 40 μm, 35 μm, and 40 μm, respectively;

[0094] Step 5: Apply high adhesion pressure sensitive adhesive on one side of the pearlescent film. The coating amount of high adhesion pressure sensitive adhesive is 40g / m 2 , curing at 115℃ for 1.5min, and covering with PET release film to obtain a colorful pearlescent film with high adhesion;

[0095] The preparation method of the high-adhesion pressure-sensitive adhesive is the same as that in Example 1.

[0096] Example 3: This example discloses a method for preparing a high-adhesion colorful pearlescent film, comprising the following steps:

[0097] Step 1: Mixing monomers of styrene, acryloyloxyethyltrimethylammonium chloride, maleic acid, 4-propyleneoxy-2-hydroxybenzophenone, azobisisobutyronitrile, and 1-dodecylmercaptan to obtain a mixed solution;

[0098] The molar ratio of styrene, acryloyloxyethyltrimethylammonium chloride, maleic acid, and 4-propyleneoxy-2-hydroxybenzophenone is 6.5:3.5:3.5:4.5, the amount of azobisisobutyronitrile added is 0.7% of the total weight of the monomers, and the amount of 1-dodecyl mercaptan added is 0.15% of the total weight of the monomers;

[0099] After heating acetone to a set temperature, the amount of acetone used is 180 times the mass of the monomers, and the mixed solution is added dropwise under nitrogen protection for 2.5 seconds. After the addition is completed, the mixture is kept refluxed at 80°C for 2 hours. After the reaction is completed, ethanol 5 times the mass of acetone is added for precipitation, filtered, and the precipitate is placed in a vacuum drying oven at 50°C for 24 hours to obtain a modifier;

[0100] Step 2: adding mica titanium pearlescent pigment to acetone at a mass ratio of mica titanium pearlescent pigment to acetone of 100:650, and ultrasonically dispersing the mica titanium pearlescent pigment at a frequency of 50 kHz for 30 minutes to obtain a pearlescent pigment dispersion;

[0101] dissolving the modifier in acetone at a mass ratio of the modifier to acetone of 23:350 to obtain a modifier solution;

[0102] Adding a modifier solution to a pearlescent pigment dispersion, wherein the mass ratio of the pearlescent pigment in the pearlescent pigment dispersion to the modifier in the modifier solution is 100:23, reacting at 85° C. for 24 hours, and after the reaction, centrifugally washing with acetone three times, and drying in a vacuum drying oven at 50° C. for 24 hours to obtain a modified pearlescent pigment;

[0103] Step 3: dissolving the organic active dye in deionized water, adding the modified pearlescent pigment, and ultrasonicating at a frequency of 60 kHz for 1.5 hours. After the ultrasonication is completed, the mixture is placed in a vacuum drying oven at 80° C. and dried to a constant weight to obtain an organic pearlescent pigment;

[0104] Among them, the mass ratio of organic reactive dye, deionized water and modified pearlescent pigment is 3.5:65:10;

[0105] Step 4: PP and organic pearlescent pigment are mixed in a mass ratio of 100:5, and the mixture is melted at a melting temperature of 230° C. to obtain a pearlescent layer melt;

[0106] PP is used as the raw material for the first protective layer and the raw material for the second protective layer, respectively, and melted at a melting temperature of 230°C to obtain a first protective layer melt and a second protective layer melt;

[0107] The first protective layer melt, the pearlescent layer melt, and the second protective layer melt are combined and extruded in a die head at an extrusion temperature of 250°C and cooled on a cooling roller to obtain a film;

[0108] The film is stretched longitudinally, stretched transversely and shaped to obtain a colorful pearlescent film;

[0109] The process parameters for longitudinal stretching, transverse stretching and shaping are the same as those in Example 1;

[0110] The colorful pearlescent film comprises a three-layer structure, which is a first protective layer, a pearlescent layer, and a second protective layer in sequence;

[0111] The thicknesses of the first protective layer, pearlescent layer, and second protective layer are 40 μm, 35 μm, and 40 μm, respectively;

[0112] Step 5: Apply high adhesion pressure sensitive adhesive on one side of the pearlescent film. The coating amount of high adhesion pressure sensitive adhesive is 40g / m 2 , curing at 115℃ for 1.5min, and covering with PET release film to obtain a colorful pearlescent film with high adhesion;

[0113] The preparation method of the high-adhesion pressure-sensitive adhesive is the same as that in Example 1.

[0114] Example 4: This example discloses a method for preparing a high-adhesion colorful pearlescent film, comprising the following steps:

[0115] Step 1: Mixing monomers of styrene, acryloyloxyethyltrimethylammonium chloride, maleic acid, 4-propyleneoxy-2-hydroxybenzophenone, azobisisobutyronitrile, and 1-dodecylmercaptan to obtain a mixed solution;

[0116] The molar ratio of styrene, acryloyloxyethyltrimethylammonium chloride, maleic acid, and 4-propyleneoxy-2-hydroxybenzophenone is 7.5:4.5:4.5:5.5, the amount of azobisisobutyronitrile added is 0.9% of the total weight of the monomers, and the amount of 1-dodecyl mercaptan added is 0.25% of the total weight of the monomers;

[0117] After heating acetone to a set temperature, the amount of acetone used is 220 times the mass of the monomers, and the mixed solution is added dropwise under nitrogen protection for 2.5 hours. After the addition is completed, the mixture is kept refluxed at 80°C for 2 hours. After the reaction is completed, ethanol 5 times the mass of acetone is added for precipitation, filtered, and the precipitate is placed in a vacuum drying oven at 50°C for 24 hours to obtain a modifier;

[0118] Step 2: adding mica titanium pearlescent pigment to acetone at a mass ratio of mica titanium pearlescent pigment to acetone of 100:750, and ultrasonically dispersing the mica titanium pearlescent pigment at a frequency of 50 kHz for 30 minutes to obtain a pearlescent pigment dispersion;

[0119] dissolving the modifier in acetone at a mass ratio of the modifier to acetone of 27:450 to obtain a modifier solution;

[0120] Adding a modifier solution to a pearlescent pigment dispersion, wherein the mass ratio of the pearlescent pigment in the pearlescent pigment dispersion to the modifier in the modifier solution is 100:27, reacting at 85° C. for 24 hours, and after the reaction is completed, centrifugally washing with acetone three times, and drying in a vacuum drying oven at 50° C. for 24 hours to obtain a modified pearlescent pigment;

[0121] Step 3: dissolving the organic active dye in deionized water, adding the modified pearlescent pigment, and ultrasonicating at a frequency of 60 kHz for 1.5 hours. After the ultrasonication is completed, the mixture is placed in a vacuum drying oven at 80° C. and dried to a constant weight to obtain an organic pearlescent pigment;

[0122] Among them, the mass ratio of organic reactive dye, deionized water and modified pearlescent pigment is 4.5:75:10;

[0123] Step 4: PP and organic pearlescent pigment are mixed in a mass ratio of 100:7 as raw materials for the pearlescent layer, and melted at a melting temperature of 230° C. to obtain a pearlescent layer melt;

[0124] PP is used as the raw material for the first protective layer and the raw material for the second protective layer, respectively, and melted at a melting temperature of 230°C to obtain a first protective layer melt and a second protective layer melt;

[0125] The first protective layer melt, the pearlescent layer melt, and the second protective layer melt are combined and extruded in a die head at an extrusion temperature of 250°C and cooled on a cooling roller to obtain a film;

[0126] The film is stretched longitudinally, stretched transversely and shaped to obtain a colorful pearlescent film;

[0127] The process parameters for longitudinal stretching, transverse stretching and shaping are the same as those in Example 1;

[0128] The colorful pearlescent film comprises a three-layer structure, which is a first protective layer, a pearlescent layer, and a second protective layer in sequence;

[0129] The thicknesses of the first protective layer, pearlescent layer, and second protective layer are 40 μm, 35 μm, and 40 μm, respectively;

[0130] Step 5: Apply high adhesion pressure sensitive adhesive on one side of the pearlescent film. The coating amount of high adhesion pressure sensitive adhesive is 40g / m 2 , curing at 115℃ for 1.5min, and covering with PET release film to obtain a colorful pearlescent film with high adhesion;

[0131] The preparation method of the high-adhesion pressure-sensitive adhesive is the same as that in Example 1.

[0132] Comparative Example 1: This comparative example discloses a method for preparing a high-adhesion colorful pearlescent film, comprising the following steps:

[0133] Step 1: dissolving the organic active dye in deionized water, adding mica titanium pearlescent pigment, and ultrasonicating at a frequency of 40 kHz for 2 hours. After the ultrasonication is completed, the mixture is placed in a vacuum drying oven at 80° C. and dried to a constant weight to obtain an organic pearlescent pigment;

[0134] Among them, the mass ratio of organic reactive dye, deionized water, and mica titanium pearlescent pigment is 3:60:8.3;

[0135] Step 2: PP, organic pearlescent pigment, and 4-propyleneoxy-2-hydroxybenzophenone are mixed in a mass ratio of 100:3.5:0.2 as a raw material for a pearlescent layer, and melted at a melting temperature of 220° C. to obtain a pearlescent layer melt;

[0136] PP is used as the raw material for the first protective layer and the raw material for the second protective layer, respectively, and melted at a melting temperature of 220°C to obtain a first protective layer melt and a second protective layer melt;

[0137] The first protective layer melt, the pearlescent layer melt, and the second protective layer melt are combined and extruded in a die head at an extrusion temperature of 240°C and cooled on a cooling roller to obtain a film;

[0138] The film is stretched longitudinally, stretched transversely and shaped to obtain a colorful pearlescent film;

[0139] The process parameters for longitudinal stretching, transverse stretching and shaping are the same as those in Example 1;

[0140] The colorful pearlescent film comprises a three-layer structure, which is a first protective layer, a pearlescent layer, and a second protective layer in sequence;

[0141] The thicknesses of the first protective layer, pearlescent layer, and second protective layer are 40 μm, 35 μm, and 40 μm, respectively;

[0142] Step 5: Apply high adhesion pressure sensitive adhesive on one side of the pearlescent film. The coating amount of high adhesion pressure sensitive adhesive is 40g / m 2 , curing at 115℃ for 1.5min, and covering with PET release film to obtain a colorful pearlescent film with high adhesion;

[0143] The preparation method of the high-adhesion pressure-sensitive adhesive is the same as that in Example 1.

[0144] Comparative Example 2: This comparative example discloses a method for preparing a high-adhesion colorful pearlescent film, comprising the following steps:

[0145] Step 1: dissolving the organic active dye in deionized water, adding mica titanium pearlescent pigment, and ultrasonicating at a frequency of 40 kHz for 2 hours. After the ultrasonication is completed, the mixture is placed in a vacuum drying oven at 80° C. and dried to a constant weight to obtain an organic pearlescent pigment;

[0146] Among them, the mass ratio of organic reactive dye, deionized water, and mica titanium pearlescent pigment is 3:60:8.3;

[0147] Step 2: PP and organic pearlescent pigment are mixed in a mass ratio of 100:3.5, and the mixture is melted at a melting temperature of 220° C. to obtain a pearlescent layer melt;

[0148] PP is used as the raw material for the first protective layer and the raw material for the second protective layer, respectively, and melted at a melting temperature of 220°C to obtain a first protective layer melt and a second protective layer melt;

[0149] The first protective layer melt, the pearlescent layer melt, and the second protective layer melt are combined and extruded in a die head at an extrusion temperature of 240°C and cooled on a cooling roller to obtain a film;

[0150] The film is stretched longitudinally, stretched transversely and shaped to obtain a colorful pearlescent film;

[0151] The process parameters for longitudinal stretching, transverse stretching and shaping are the same as those in Example 1;

[0152] The colorful pearlescent film comprises a three-layer structure, which is a first protective layer, a pearlescent layer, and a second protective layer in sequence;

[0153] The thicknesses of the first protective layer, pearlescent layer, and second protective layer are 40 μm, 35 μm, and 40 μm, respectively;

[0154] Step 3: Apply high adhesion pressure sensitive adhesive on one side of the pearlescent film. The coating amount of high adhesion pressure sensitive adhesive is 40g / m 2 , curing at 115℃ for 1.5min, and covering with PET release film to obtain a colorful pearlescent film with high adhesion;

[0155] The preparation method of the high-adhesion pressure-sensitive adhesive is the same as that in Example 1.

[0156] In the above embodiments and comparative examples, the PP used to prepare the pearlescent layer, the first protective layer, and the second protective layer is the same, which is a BOPP special resin PP purchased from Dongguan Jiaqing Plastic Raw Materials Co., Ltd., with a product number of PPR-FT03-S; the mica titanium pearlescent pigment is a silvery white mica titanium pearlescent pigment purchased from Lianyungang Rongbai New Materials Co., Ltd., with a particle size of 10000; the PET release film is purchased from Suzhou Jiateng Packaging Materials Technology Co., Ltd., with a brand name of JT-561 and a thickness of 0.05 mm; the organic reactive dye is Reactive Brilliant Red XB, with a CAS number of 17752-85-1 and a structural formula of:

[0157] Test example .

[0158] The high-adhesion colorful pearlescent films prepared in Examples 1-4 and Comparative Examples 1-2 were subjected to a light stability test: the high-adhesion colorful pearlescent films were irradiated with 380nm ultraviolet light for 4000 hours, and the color change before and after irradiation, i.e., the color difference (ΔE), was measured. The test results are shown in Table 1:

[0159]

[0160] As shown in Table 1, the high-adhesion colorful pearlescent film prepared by the present invention has good light stability. When preparing the colorful pearlescent film, the organic pearlescent pigment is prepared from a modified pearlescent pigment and an organic reactive dye, wherein the modifier is prepared from styrene, acryloyloxyethyltrimethylammonium chloride, maleic acid, and 4-propyleneoxy-2-hydroxybenzophenone as monomers. The carboxyl group in the modifier acts as an anchoring group to react with the pearlescent pigment, and the cationic group in the modifier reacts with the organic reactive dye. Under the action of the modifier, the pearlescent pigment and the organic reactive dye can be bonded, thereby improving the dispersibility of the pearlescent pigment and the organic reactive dye in PP; with the action of the solvation chain, the pearlescent pigment and the organic reactive dye have good compatibility with PP; the hydroxybenzophenone group in the modifier can absorb ultraviolet rays, thereby improving the light stability of the colorful pearlescent film;

[0161] In addition, mica titanium pearlescent pigment is formed by coating a layer of TiO2 or alternating multiple layers of TiO2 on a natural mica flake as a matrix. It can also act as a UV absorber to improve the light stability of the colorful pearlescent film. Compared with Example 1, in Comparative Example 1, the mica titanium pearlescent pigment was not modified with a modifier, and its dispersibility in PP was reduced. In addition, the light stabilizer 4-propyleneoxy-2-hydroxybenzophenone and other monomers did not form a modifier, and 4-propyleneoxy-2-hydroxybenzophenone was prone to migration, resulting in a decrease in light stability. In Comparative Example 2, the mica titanium pearlescent pigment was not modified with a modifier, and no light stabilizer was introduced. The light stability of the colorful pearlescent film was significantly reduced.

[0162] While 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 these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a high-adhesion colorful pearlescent film, characterized in that: The following steps are involved: Step 1: Prepare a modifier using styrene, acryloyloxyethyltrimethylammonium chloride, maleic acid, and 4-propyleneoxy-2-hydroxybenzophenone as monomers; Step 2: reacting the modifier with the pearlescent pigment to prepare a modified pearlescent pigment; Step 3: reacting the modified pearlescent pigment with an organic reactive dye to prepare an organic pearlescent pigment; Step 4: PP and organic pearlescent pigment are mixed as raw materials for the pearlescent layer, and melted to obtain a pearlescent layer melt; PP is used as the raw material for the first protective layer and the raw material for the second protective layer, respectively, and melted to obtain a first protective layer melt and a second protective layer melt; The first protective layer melt, the pearlescent layer melt, and the second protective layer melt are combined and extruded in a die head, and cooled to obtain a film; The film is biaxially stretched to obtain a colorful pearlescent film; Step 5: Apply high-adhesion pressure-sensitive adhesive on one side of the pearlescent film, cure it, and cover it with a release film to obtain a high-adhesion colorful pearlescent film.

2. The method for preparing a high-adhesion colorful pearlescent film according to claim 1, characterized in that: In the step 1, preparing the modifier specifically includes: Mixing monomers of styrene, acryloyloxyethyltrimethylammonium chloride, maleic acid, 4-propyleneoxy-2-hydroxybenzophenone, an initiator, and 1-dodecyl mercaptan to obtain a mixed solution; After heating acetone to a set temperature, the mixed solution was added dropwise under nitrogen protection. After the addition was complete, the mixture was reacted. After the reaction was completed, the mixture was precipitated, filtered, and dried to obtain a modifier.

3. The method for preparing a high-adhesion colorful pearlescent film according to claim 2, characterized in that: The molar ratio of styrene, acryloyloxyethyltrimethylammonium chloride, maleic acid, and 4-propyleneoxy-2-hydroxybenzophenone is (6-8):(3-5):(3-5):(4-6), the amount of the initiator added is 0.6%-1% of the total weight of the monomers, and the amount of 1-dodecyl mercaptan added is 0.1%-0.3% of the total weight of the monomers. The reaction conditions are to keep the reaction under reflux at a set temperature for 1-3 hours; The set temperature is 70-90°C.

4. The method for preparing a high-adhesion colorful pearlescent film according to claim 1, characterized in that: In the step 2, the modified pearlescent pigment is prepared, which specifically includes: Adding pearlescent pigment into acetone and performing ultrasonic dispersion to obtain pearlescent pigment dispersion; dissolving the modifier in acetone to obtain a modifier solution; The modifier solution is added to the pearlescent pigment dispersion to react. After the reaction is completed, the modified pearlescent pigment is washed by centrifugation and dried to obtain the modified pearlescent pigment.

5. The method for preparing a high-adhesion colorful pearlescent film according to claim 4, characterized in that: The mass ratio of the pearlescent pigment to the modifier is 100:(20-30), and the reaction conditions are 75-95° C. for 18-36 hours.

6. The method for preparing a high-adhesion colorful pearlescent film according to claim 1, characterized in that: In the step 3, preparing the organic pearlescent pigment specifically includes: The organic active dye is dissolved in deionized water, and the modified pearlescent pigment is added, and ultrasonication is performed. After the ultrasonication is completed, the modified pearlescent pigment is dried to obtain the organic pearlescent pigment. The mass ratio of the organic active dye, deionized water and modified pearlescent pigment is (3-5):(60-80):10, and the ultrasonication condition is 40-80 kHz frequency for 1-2 hours.

7. The method for preparing a high-adhesion colorful pearlescent film according to claim 1, characterized in that: In the fourth step, when preparing the pearlescent layer melt, the mass ratio of PP to organic pearlescent pigment is 100:(4-8), and the melting temperature is 220-240°C; When preparing the first protective layer melt and the second protective layer melt, the melting temperature is 220-240°C; Extrusion temperature is 240-260℃; The biaxial stretching process includes longitudinal stretching, transverse stretching and shaping.

8. The method for preparing a high-adhesion colorful pearlescent film according to claim 7, characterized in that: The longitudinal stretching comprises: preheating at a temperature of 105-115°C, longitudinal stretching at a temperature of 80-100°C, and a stretching ratio of 300-500%; The transverse stretching comprises: preheating at a temperature of 160-180°C, and transverse stretching at a temperature of 150-170°C, with a stretching ratio of 600-800%; The setting temperature is 160-170°C.

9. The method for preparing a high-adhesion colorful pearlescent film according to claim 1, characterized in that: In the step 5, the coating amount of the high adhesion pressure sensitive adhesive is 30-50g / m 2 , curing conditions are curing at 110-120℃ for 1-2min; The high-adhesion pressure-sensitive adhesive in step 5 is prepared by the following steps: S1, mixing butyl acrylate, isooctyl acrylate, methyl methacrylate, 2-(perfluorobutyl)ethyl acrylate, glycidyl methacrylate, hydroxyethyl acrylate, ethyl acetate, and azobisisobutyronitrile to obtain a reaction solution; dividing the reaction liquid into a first part of the reaction liquid and a second part of the reaction liquid; S2, heating the first part of the reaction liquid for reaction, adding the second part of the reaction liquid dropwise after the addition is complete, continuing the reaction, cooling after the reaction is complete, adding a crosslinking agent and a tackifying agent to obtain a high-adhesion pressure-sensitive adhesive; Among them, the mass ratio of butyl acrylate, isooctyl acrylate, methyl methacrylate, 2-(perfluorobutyl)ethyl acrylate, glycidyl methacrylate, hydroxyethyl acrylate, ethyl acetate, azobisisobutyronitrile, crosslinking agent and viscosity-increasing agent is (50-60):(65-75):(60-80):(30-50):(40-60):(20-30):(250-350):(5-10):(10-20):(20-30), the heating reaction condition is reflux reaction at a temperature of 70-90°C for 1-2h, and the continued reaction condition is reflux reaction at a temperature of 70-80°C for 3-5h.

10. A high-adhesion colorful pearlescent film prepared by the method for preparing a high-adhesion colorful pearlescent film according to any one of claims 1 to 9.

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