Production and preparation process of PVC decorative film

Abstract

The invention relates to the technical field of PVC decorative films, in particular to a production and preparation process of a PVC decorative film. The problems of poor mechanical property and insufficient barrier property of the decorative film in the prior art are solved. The preparation method comprises the following steps: modifying PVC resin through alkenyl-terminated polydimethylsiloxane to obtain modified PVC; dispersing and modifying nano titanium dioxide to obtain modified titanium dioxide; acrylic resin is obtained from an acrylic monomer and fluorine-containing acrylic acid; the modified PVC, the modified titanium dioxide, acrylic resin, a toughening auxiliary agent and other auxiliary agents are subjected to multi-stage mixing, melt extrusion, three-stage calendering, embossing and cooling, and the PVC decorative film is prepared. The mechanical property is improved through the synergistic effect of the toughening aid and siloxane; by introducing modified titanium dioxide and fluorine-containing acrylic resin, the barrier property of the decorative film is synergistically improved.

Description

Technical Field

[0001] The invention relates to the technical field of PVC decorative films, in particular to a production process for a PVC decorative film. Background Art

[0002] PVC decorative film occupies an important position in many industries such as architectural decoration, furniture manufacturing, packaging, etc. due to its low cost, easy processing and molding, and rich and diverse color performance. However, based on the current production and preparation technology, PVC decorative film has some significant technical bottlenecks, among which insufficient mechanical properties and poor barrier properties have become the key factors restricting its further development and wide application.

[0003] The PVC resin used in traditional PVC decorative films has poor bonding ability between PVC molecular chains, weak interaction between molecular chains, and lacks an effective cross-linking or reinforcement system, which reduces the mechanical strength and toughness of the decorative film. During use, when the PVC decorative film is hit by external forces, scratches and even damage will easily appear on the surface of the film, which not only destroys the overall decorative effect, but may also cause the film to fall off, resulting in a waste of resources.

[0004] In addition, there are many molecular gaps and defects inside the PVC decorative film, which allows gas and small liquid molecules to pass through more easily; in the field of food and drug packaging, ordinary PVC decorative film is difficult to effectively block the penetration of oxygen and water vapor. The invasion of oxygen will accelerate the oxidation and rancidity of food, and water vapor will cause food to become damp and deteriorate, greatly shortening the shelf life of food and increasing the risk of deterioration; for the packaging of precision electronic components, the existing PVC decorative film cannot resist the invasion of external water vapor and corrosive gases, resulting in electronic component short circuits, corrosion and other faults, seriously affecting the quality and reliability of electronic products.

[0005] In summary, the serious deficiencies in mechanical properties and barrier properties of PVC decorative film have greatly restricted its in-depth application and development in various industries.

[0006] Therefore, a production process of PVC decorative film is proposed. Summary of the invention

[0007] The object of the present invention is to provide a production and preparation process of PVC decorative film. The present invention comprises the following steps: modifying PVC resin by terminal olefin polydimethylsiloxane to obtain modified PVC; dispersing and modifying nano titanium dioxide to obtain modified titanium dioxide; obtaining acrylic resin by reacting acrylic monomer with fluorine-containing acrylic acid; subjecting the modified PVC, modified titanium dioxide, acrylic resin, toughening aid and other aids to multi-stage mixing, melt extrusion, three-stage calendering, embossing and cooling to obtain PVC decorative film; improving mechanical properties by the synergistic effect of toughening aid and siloxane; and synergistically improving the barrier properties of the decorative film by introducing modified titanium dioxide and fluorine-containing acrylic resin.

[0008] To achieve the above object, the present invention provides the following technical solutions:

[0009] The present invention provides a production process for a PVC decorative film. The production process for the PVC decorative film comprises the following steps:

[0010] The modified titanium dioxide is added to the modified PVC, acrylic resin, polyvinylidene chloride, toughening agent and additives by step-by-step mixing and mixing, and the mixture is stirred and mixed to obtain a rubber compound; the rubber compound is melt-extruded to obtain a PVC mixture;

[0011] The PVC mixture is calendered by a three-stage calendering method to obtain calendered PVC; the calendered PVC is subjected to drawing and embossing treatment to obtain a film material; the film material is cooled and curled to obtain a PVC decorative film;

[0012] Modified PVC is prepared by swelling PVC resin and modifying it with terminal olefin-based polydimethylsiloxane.

[0013] The modified titanium dioxide is obtained by modifying nano titanium dioxide by ultrasound, centrifugation and methacryloxypropyltrimethoxysilane;

[0014] The acrylic resin is obtained by polymerization initiated by methacrylate, ethyl acrylate and perfluorooctylethyl acrylate;

[0015] The toughening agent is obtained by polymerization of terminal olefin polydimethylsiloxane, maleic anhydride, methacrylate and styrene; PVC is a polyvinyl chloride resin with a polymerization degree of 800-1200;

[0016] Additives include zinc stearate, antioxidant 1010, calcium carbonate and dioctyl phthalate.

[0017] Preferably, the preparation of modified PVC comprises the following steps:

[0018] The PVC resin is crushed to obtain resin particles, and vacuum dried at 100° C. for 5 hours to obtain PVC particles; 90-110 parts of PVC particles are added into tetrahydrofuran to dissolve, and stirred to obtain swollen PVC; 10-20 parts of terminal olefin polydimethylsiloxane are added into tetrahydrofuran to dissolve to obtain a solution; the solution is slowly added into the swollen PVC to obtain a mixed system; the mixed system is heated, 8 parts of dibenzoyl peroxide are added, and a reaction system is obtained by modification reaction; the reaction system is added into a methanol solution, filtered and washed, and vacuum dried to obtain a modified PVC.

[0019] Preferably, the temperature of the modification reaction is 80-100° C.; the time of the modification reaction is 6-8 h.

[0020] Preferably, the preparation of modified titanium dioxide comprises the following steps:

[0021] Dissolve methacryloxypropyltrimethoxysilane in 95% ethanol solution, add acetic acid to adjust the pH of the system to 3, and stir for 2 hours to obtain a modifier solution; slowly add nano titanium dioxide into anhydrous ethanol solution to obtain a suspension; ultrasonically treat the suspension to obtain a treated liquid; centrifuge the treated liquid at a low speed for 10 minutes, and vacuum dry to obtain treated particles; slowly add the treated particles into the modifier solution, carry out modification reaction at 500 rpm and 60-80°C for 1-3 hours, and dry and grind to obtain modified titanium dioxide.

[0022] Preferably, the frequency of ultrasonic treatment is 40-70 kHz; the time of ultrasonic treatment is 20-40 min; and the mass ratio of nano-titanium dioxide to methacryloxypropyltrimethoxysilane is 8-12:1.

[0023] Preferably, the preparation of acrylic resin comprises the following steps:

[0024] 30 parts of methacrylate, 20 parts of ethyl acrylate and 5-15 parts of perfluorooctyl ethyl acrylate are mixed, and stirred at 200 rpm for 1 hour to obtain a mixed system; toluene is added to a flask, replaced with nitrogen, and the mixed system is slowly added dropwise, and stirred for 30 minutes to obtain a reaction substrate; 3 parts of benzoyl peroxide are dissolved in toluene to obtain an initiator solution; the reaction substrate is heated to 70-90°C, the initiator solution is slowly added to the reaction substrate, the rpm is maintained at 200, the reaction is performed for 2-6 hours, and dodecyl mercaptan is added to control the molecular weight to 50,000-100,000 to obtain an acrylic resin.

[0025] Preferably, the preparation of the toughening aid comprises the following steps:

[0026] 10 parts of nonylphenol polyoxyethylene ether are added into deionized water, and stirred to dissolve to obtain an emulsion; 45-60 parts of terminal olefin polydimethylsiloxane are slowly added dropwise into the emulsion, and stirred to disperse; dibenzoyl peroxide is then slowly added, and the temperature is raised to react to obtain latex particles; 5-15 parts of maleic anhydride, 24 parts of methacrylate, and 16 parts of styrene are added into the latex particles, and stirred at 400 rpm for 30 minutes to obtain a mixed system; 5 parts of azobisisobutyronitrile are added into the mixed system, and polymerization reaction is carried out at 80-100° C. for 2-5 hours to obtain a reaction product; a calcium chloride solution is added into the reaction product, and the product is separated and centrifuged, and washed and dried to obtain a toughening agent.

[0027] Preferably, the three-stage calendering method includes: the calendering temperature in the first stage is 160-165°C, and the calendering roller speed ratio is 1.2-1.3; the calendering temperature in the second stage is 170-175°C, and the calendering roller speed ratio is 1.3-1.4; the calendering temperature in the third stage is 155-160°C, and the calendering roller speed ratio is 1.4-1.5.

[0028] Preferably, the embossing temperature is 50-60°C, the pressure is 0.5-1 MPa; and the cooling temperature is controlled at 30-40°C.

[0029] Preferably, the PVC decorative film comprises 80-100 parts of modified PVC, 10-25 parts of acrylic resin, 10 parts of polyvinylidene chloride, 8-20 parts of toughening additive and 8-20 parts of modified titanium dioxide.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] 1. The present invention modifies PVC resin by terminal olefin polydimethylsiloxane, and the entanglement effect enhances stress transfer to form a complex network structure; the three-stage calendering process makes the molecular chain orientation orderly and forms a crystalline structure; the addition of toughening additives can disperse stress and prevent crack propagation, and the tensile strength and elongation at break are improved under synergistic effect.

[0032] 2. The present invention uses terminal olefinic polydimethylsiloxane as the toughening agent core layer structure, utilizes silicon-oxygen bonds to absorb impact energy, and has good compatibility with modified PVC and a stable microstructure; the addition of maleic anhydride can improve the dispersibility and compatibility of the toughening agent with the matrix system, coordinate the deformation and energy absorption of each component under the action of external force, and effectively improve the impact strength of the decorative film by controlling the amount of the toughening agent.

[0033] 3. The present invention modifies the nano titanium dioxide by adding modified titanium dioxide, performs dispersion treatment, improves the dispersion uniformity of the modified titanium dioxide in the matrix, and uses polyvinylidene chloride in coordination to form an organic-inorganic hybrid structure to further improve the oxygen barrier performance of the decorative film.

[0034] 4. The present invention improves the water vapor barrier capability of the decorative film by introducing acrylic resin prepared by fluorine-containing monomers, controlling the addition amount and molecular weight of the acrylic resin, changing the addition method of the acrylic resin, and coordinating the addition of terminal olefin polysiloxane. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 The graphs of tensile strength and elongation at break of Examples 1-3, Comparative Example 1, and Comparative Examples 5-7 of the present invention are shown;

[0036] Figure 2 This is a graph showing the impact strength changes of Examples 8-9, Comparative Examples 7-9, and Comparative Example 13 of the present invention. DETAILED DESCRIPTION

[0037] The following will be combined with the drawings in 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.

[0038] See also Figure 1 to Figure 2 The present invention provides a PVC decorative film production process, and the technical solution is as follows:

[0039] Example 1

[0040] 6 mol of hydroxy-terminated polydimethylsiloxane and 0.08 mol of tert-butylhydroquinone were added into a flask, 10 ml of dichloromethane was slowly added, and the mixture was stirred at room temperature for 30 min to obtain a mixed solution; 15 mol of acryloyl chloride and 5 ml of triethylamine were slowly added into the mixed solution, and the addition was completed within 30 min, the temperature was raised to 40°C, and the reaction was carried out for 3 h to obtain olefin-terminated polydimethylsiloxane; the vinyl content was controlled to be 0.5%-1.5%; the molecular weight range was 5000-1000;

[0041] Select PVC resin with a degree of polymerization of 800-1200, crush it to obtain resin particles, and vacuum dry it at 100°C for 5 hours to obtain PVC particles; add 100 parts of PVC particles into a flask, add 50 ml of tetrahydrofuran to dissolve, and stir at room temperature at 200 rpm for 2 hours to obtain swollen PVC; add 15 parts of terminal olefin polydimethylsiloxane into 5 ml of tetrahydrofuran and dissolve to obtain a solution; slowly add the solution into the swollen PVC, and control the dropwise addition time to be 45 minutes to obtain a mixed system; heat the mixed system to 80°C, add 8 parts of dibenzoyl peroxide, and keep the temperature for reaction for 8 hours to obtain a reaction system; add the reaction system into 250 ml of methanol, stir at 150 rpm to precipitate, filter the precipitate, wash with tetrahydrofuran, rinse with methanol, wash again with deionized water, and vacuum dry at 80°C for 2 hours to obtain modified PVC;

[0042] Dissolve 2 parts of KH-570 (5 ml) in 95% ethanol solution, add 2 ml of acetic acid to adjust the pH of the system to 3, and stir in a magnetic stirrer at 50°C for 2 hours to obtain a modifier solution; slowly add 20 parts of nano titanium dioxide into the anhydrous ethanol solution to obtain a suspension; subject the suspension to ultrasonic treatment, with the ultrasonic frequency set to 50 kHz and the ultrasonic time set to 30 minutes to obtain a treated liquid; place the treated liquid in a low-speed centrifuge and centrifuge at a speed of 3000 r / min for 10 minutes, and vacuum dry at 60°C to obtain treated particles; slowly add the treated particles into the modifier solution, carry out a modification reaction at 60°C at 500 rpm for 2 hours, dry at 100°C for 2 hours, and grind for 30 minutes to obtain modified titanium dioxide.

[0043] Preparation of acrylic resin:

[0044] 30 parts of methacrylate, 20 parts of ethyl acrylate and 10 parts of perfluorooctyl ethyl acrylate were added into a flask and mixed, and stirred at 200 rpm for 1 hour to obtain a mixed system; toluene was added into the flask, replaced with nitrogen, and the mixed system was slowly added dropwise at 200 rpm, and stirred for 30 minutes to obtain a reaction substrate; 3 parts of benzoyl peroxide were dissolved in toluene to obtain an initiator solution; the reaction substrate was heated to 80°C, the initiator solution was slowly added into the reaction substrate, the rpm was maintained at 200, the reaction was performed for 5 hours, and dodecyl mercaptan was added to control the molecular weight to obtain an acrylic resin.

[0045] Preparation of toughening additives:

[0046] 10 parts of nonylphenol polyoxyethylene ether are added into deionized water, and stirred until completely dissolved to obtain an emulsion; 50 parts of terminal olefin polydimethylsiloxane are slowly dropped into the emulsion, and stirred and dispersed at 500 rpm for 20 minutes; then dibenzoyl peroxide is slowly added, the temperature is raised to 80°C, and the reaction is performed for 2 hours to obtain latex particles; 10 parts of maleic anhydride, 24 parts of methacrylate, and 16 parts of styrene are added into the latex particles, and the mixture is stirred at 400 rpm for 30 minutes to obtain a mixed system; 5 parts of azobisisobutyronitrile are added into the mixed system, the temperature is raised to 90°C, and the polymerization reaction is performed for 3 hours to obtain a reaction product; calcium chloride solution is added into the reaction product, separated and centrifuged, washed with deionized water, and vacuum dried at 100°C for 2 hours to obtain a toughening agent.

[0047] 15 parts of modified titanium dioxide were added to 5 parts of dioctyl phthalate, mixed and stirred at 1000 rpm for 30 minutes, and a mixed material was obtained by dispersion; the mixed material was added to 90 parts of modified PVC resin, and mixed at 120°C for 20 minutes; 20 parts of acrylic resin were added, and the mixture was mixed at a temperature of 10 minutes to obtain a mixed system; 10 parts of polyvinylidene chloride were added, and the mixture was mixed at a temperature of 5 minutes; 15 parts of toughening aid, 5 parts of zinc stearate, 3 parts of antioxidant 1010, and 1 part of calcium carbonate were added to the mixed system, the temperature was raised to 150°C, and the mixture was mixed at 500 r / min for 30 minutes to obtain a mixed rubber; the mixed rubber was melt-extruded in a twin-screw extruder to obtain a PVC mixture;

[0048] The PVC mixture is passed through a calender and calendered in a three-stage calendering method, wherein the calendering temperature of the first stage is 160-165°C and the calendering roller speed ratio is 1.2-1.3; the calendering temperature of the second stage is 170-175°C and the calendering roller speed ratio is 1.3-1.4; the calendering temperature of the third stage is 155-160°C and the calendering roller speed ratio is 1.4-1.5 to obtain calendered PVC; the calendered PVC is passed through a taking device, and the calendered film material is taken to an embossing device for embossing treatment, the embossing temperature is 50-60°C, and the pressure is 0.5-1MPa; the embossed film material is cooled by a cooling roller, the cooling temperature is controlled at 30-40°C, and curled to obtain a PVC decorative film.

[0049] Examples 2-7 refer to the preparation methods and parameter conditions of Example 1, with the differences shown in Table 1.

[0050] Table 1 Parameter changes of Examples 1-7

[0051]

[0052] Comparative Example 1 refers to Example 1, except that the PVC resin is not modified.

[0053] Comparative Example 2 refers to Example 1, except that the PVC is not subjected to swelling treatment during the modification process.

[0054] Comparative Example 3 refers to Example 1, except that the amount of terminal olefinic polydimethylsiloxane added is 30 parts.

[0055] Comparative Example 4 refers to Example 1, except that the amount of terminal alkenyl polydimethylsiloxane added is 10 parts.

[0056] Comparative Example 5 refers to Example 1, except that a one-stage calendering is used, the calendering temperature is 160-165°C, and the calendering roller speed ratio is 1.3-1.4.

[0057] Comparative Example 6 refers to Example 1, except that three-stage calendering is used, but the calendering temperature and calendering roller speed are increased.

[0058] Comparative Example 7 refers to Example 1, except that no toughening agent is added.

[0059] Experimental Example 1 Tensile Properties Test

[0060] The PVC decorative films prepared in Examples 1-7 and Comparative Examples 1-7 were subjected to tensile performance tests using a universal mechanical testing machine (XWW-20A) to test the tensile strength and elongation at break of the materials. The test was performed in accordance with GB / T 1040.5-2008. During the test, the test specimens were stably fixed with a clamping specimen, and the tensile rate was set to 15 mm / min. The test results are shown in Table 2. The tensile strength and elongation at break of the PVC decorative films prepared in Examples 1-3, Comparative Examples 1, and Comparative Examples 5-7 were shown in Table 2. Figure 1 shown.

[0061] Table 2 Tensile performance test of Examples 1-7 and Comparative Examples 1-7

[0062] Example Tensile strength / MPa Elongation at break / % Example 1 42 228 Example 2 38 216 Example 3 40 225 Example 4 36 226 Example 5 44 213 Example 6 40 218 Example 7 38 220 Comparative Example 1 32 182 Comparative Example 2 35 158 Comparative Example 3 30 162 Comparative Example 4 36 184 Comparative Example 5 32 195 Comparative Example 6 38 205 Comparative Example 7 35 196

[0063] Through Table 2, Figure 1The results show that the tensile properties of the PVC decorative film in Comparative Example 1 that is not modified by terminal olefinic polysiloxane are significantly lower than those in Examples 1-7. Since terminal olefinic polysiloxane contains flexible siloxane bonds, it can be physically or chemically entangled with the PVC molecular chains when added to the PVC system. During the stretching process, these entangled structures can effectively transfer stress, thereby enhancing the synergistic effect between the molecular chains. In combination with Comparative Example 2, in which the PVC is not subjected to swelling treatment, the elongation at break of the decorative film is significantly reduced, and the spacing between the PVC molecular chains subjected to swelling treatment is increased, which is conducive to the insertion and reaction of terminal olefinic polydimethylsiloxane molecules, so that the flexible siloxane bonds can be evenly dispersed between the PVC molecular chains, thereby reducing the PVC molecular chains. The interaction force between the sub-chains makes it easier for the molecular chain to slip and stretch under the action of external force, significantly improving the elongation at break. At the same time, the entangled structure with the PVC molecular chain can maintain a certain strength to avoid the reduction of tensile strength; at the same time, nano-titanium dioxide is evenly dispersed in the system, providing more physical cross-linking points for the terminal olefin polysiloxane and the PVC molecular chain; the introduction of acrylic resin can produce a synergistic effect with the terminal olefin polysiloxane, further optimize the interaction between the molecular chains, interpenetrate and entangle with the PVC molecular chain, form a complex network structure, and further improve the tensile properties; Comparative Examples 3-4, by controlling the amount of terminal olefin polydimethylsiloxane, show significantly reduced tensile properties. When the dosage is small, the terminal olefin polysiloxane molecules are dispersed between the PVC molecular chains, and some terminal olefins are physically entangled with the PVC molecular chains, and the interaction between the molecular chains is enhanced. During the stretching process, it can withstand greater external forces and the tensile strength is improved. In addition, the flexible chain segments of polysiloxane give the PVC molecular chains a certain flexibility, which increases the elongation at break. However, too much terminal olefin polysiloxane will lead to the formation of more polysiloxane-enriched areas in the system. The compatibility of these areas with the PVC matrix becomes poor, and the interfacial bonding force is weakened. Due to the uneven dispersion, the internal structure of the material is easily damaged and cannot effectively withstand tensile stress, resulting in reduced tensile strength. The increase in elongation at break will also make the material easier to Deformation; In Comparative Example 5, a single-stage calendering process is used, and the tensile properties of the obtained decorative film are significantly deteriorated. Since multi-stage calendering can make the PVC molecular chains gradually and more fully oriented along the calendering direction at different stages, each stage of calendering further adjusts and optimizes the orientation of the molecular chains during the calendering process, making the arrangement of the molecular chains more orderly, and at the same time, it is beneficial for the PVC molecular chains to form a crystalline structure. The crystalline region can enhance the interaction force between the molecular chains and improve the rigidity and strength of the material. During the stretching process, the crystalline region can serve as a physical cross-linking point to limit the slippage of the molecular chain, thereby increasing the tensile strength and reducing the elongation at break. At the same time, multi-stage calendering can make the stress distribution inside the PVC decorative film more uniform;In Comparative Example 6, the calendering temperature and roller speed ratio are changed. In the first calendering process, the lower calendering ratio and moderate temperature can allow the PVC molecular chains to begin to arrange along the calendering direction to a certain extent, laying the foundation for the subsequent improvement of tensile properties; the three-stage calendering is mainly to shape the PVC decorative film, so that the orientation state of the molecular chain is finally fixed. The calendering temperature is appropriately reduced, so that the molecular chain can be quickly cooled and shaped in the existing orientation state, the arrangement structure of the molecular chain is stabilized, and the tensile properties of the decorative film are improved; in Comparative Example 7, no toughening agent is added, which significantly reduces the tensile properties. The addition of toughening particles can absorb and disperse stress, and at the same time, it has a good interface bonding with the PVC matrix. During stretching, the dispersed phase particles can prevent the generation of microcracks. and expansion, the material can withstand greater external force during the stretching process, improve the tensile strength, and the flexible siloxane therein is used as the core structure, and the introduction of siloxane further improves the compatibility of the toughening agent with the modified PVC matrix, and can be stretched and deformed under the action of external force, so that the PVC molecular chain has more opportunities to be oriented and slipped, thereby greatly increasing the deformation ability of the material before breaking, and the elongation at break is significantly improved; In summary, the present invention uses terminal olefin polydimethylsiloxane to modify the PVC resin, and at the same time introduces a toughening agent containing a siloxane group to improve the compatibility, while utilizing the synergistic effect of siloxane, modified titanium dioxide and acrylic resin, controlling the conditions of the calendering process, and improving the tensile properties of the decorative film. ;

[0064] Embodiment 8 is the same as embodiment 1;

[0065] Examples 9-13 refer to the preparation method and parameter conditions of Example 8, with the differences as shown in Table 3.

[0066] Comparative Example 7 refers to Example 8, except that no toughening agent is added.

[0067] Comparative Example 8 refers to Example 8, except that the raw material of the core layer in the toughening additive is selected from butadiene rubber.

[0068] Comparative Example 9 refers to Example 8, except that no maleic anhydride is added to the toughening agent.

[0069] Comparative Example 10 refers to Example 8, except that MBS is used as a toughening agent.

[0070] Comparative Example 11 refers to Example 8, except that the amount of toughening aid used is 40 parts.

[0071] Comparative Example 12 refers to Example 8, except that the amount of toughening aid used is 5 parts.

[0072] Comparative Example 13 refers to Example 8, except that the PVC resin is not modified.

[0073] Experimental Example 2 Impact Strength Test

[0074] The PVC decorative films prepared in Examples 8-13 and Comparative Examples 7-13 were tested for impact strength using a pendulum impact tester in accordance with GB / T1843-2008. The test results are shown in Table 3. The impact strength changes of Examples 8-9, Comparative Examples 7-9 and Comparative Example 13 are shown in Table 3. Figure 2 shown.

[0075] Table 3 Impact strength test of Examples 8-13 and Comparative Examples 7-13

[0076]

[0077] From the results in Table 3, it can be seen that in Comparative Examples 7-10, the impact strength is significantly reduced compared with Examples 8-13 by changing the toughening aid. First, the terminal olefinic polydimethylsiloxane is used as a toughening aid made from a core layer structure. The terminal olefinic polydimethylsiloxane has a unique silicon-oxygen bond structure with a long bond length and a large bond angle, which gives the decorative film excellent flexibility and a low glass transition temperature. When the PVC decorative film is impacted, the molecular chain of the terminal olefinic polydimethylsiloxane can quickly undergo elastic deformation, like countless tiny springs, absorbing a large amount of impact energy through its own stretching, torsion, etc. Compared with butadiene rubber, it can efficiently convert impact energy into its own internal energy, thereby improving the impact resistance of the decorative film. In addition, the terminal olefinic polydimethylsiloxane has a unique silicon-oxygen bond structure with a long bond length and a large bond angle, which gives the decorative film excellent flexibility and a low glass transition temperature. When the PVC decorative film is impacted, the molecular chain of the terminal olefinic polydimethylsiloxane can quickly undergo elastic deformation, like countless tiny springs, absorbing a large amount of impact energy through its own stretching, torsion, etc. Compared with butadiene rubber, it can efficiently convert impact energy into its own internal energy, thereby improving the impact resistance of the decorative film. The polydimethylsiloxane has good compatibility with the modified PVC matrix and can be evenly dispersed in the PVC system to form a stable microstructure to further improve the impact strength; secondly, maleic anhydride contains unsaturated double bonds and polar anhydride groups, and its introduction plays a "bridge" role. It can react with the PVC molecular chain and interact with the polar groups in the toughening agent, thereby enhancing the dispersibility and compatibility of the toughening agent in the PVC matrix. The PVC matrix, toughening agent and other additives in the system form a more orderly and tighter structure under the action of maleic anhydride, better coordinate the deformation and energy absorption process of each component, effectively prevent the generation and expansion of cracks, and cooperate with each component to improve the impact strength of the decorative film; Comparative Example 11- 12, the adjustment of the amount of toughening agent has a significant effect on the impact strength. A relatively small amount of toughening agent disperses a relatively small number of particles in the PVC matrix, and the sites that can absorb and disperse the impact energy are limited. The distance between particles is large, and an effective energy absorption network cannot be formed, which reduces the impact strength of the decorative film; excessive toughening agent particles will agglomerate in the PVC matrix, which increases the effective action distance between particles, forms stress concentration points, and destroys the originally uniform energy absorption network. When impacted, these stress concentration points will preferentially cause the destruction of the material. In addition, excessive toughening agents will also reduce the continuity and rigidity of the PVC matrix, making the mechanical properties of the entire material system unbalanced, resulting in a decrease in impact strength; Comparative Example 13, if the PVC resin is not modified, the impact strength will also be significantly affected. The flexible structure of terminal olefin polydimethylsiloxane can effectively disperse the stress when impacted and directly act on the PVC molecular chain. At the same time, the modified PVC resin can improve the compatibility with the toughening agent to achieve a synergistic toughening effect. Terminal olefin polydimethylsiloxane can assist the toughening agent to be better dispersed in the PVC matrix, enhance the interaction with the PVC molecular chain, and thus improve the impact strength of the decorative film. In summary, the PVC resin is modified with terminal olefin polysiloxane, and terminal olefin polysiloxane is used as the core layer structure of the toughening agent, the amount and type of the toughening agent are controlled, and the synergistic effect of the two is utilized to jointly improve the impact strength of the material.

[0078] Embodiment 14 is the same as embodiment 1;

[0079] Examples 15-19 refer to the preparation method and parameter conditions of Example 14, and the differences are shown in Table 4.

[0080] Comparative Example 14 refers to Example 14, except that no modified titanium dioxide is added.

[0081] Comparative Example 15 refers to Example 14, except that titanium dioxide is added without modification.

[0082] Comparative Example 16 refers to Example 14, except that the nano titanium dioxide is not subjected to ultrasonic centrifugation treatment during the preparation of the modified titanium dioxide.

[0083] Comparative Example 17 refers to Example 14, except that the PVC mixture is not prepared by stepwise feeding.

[0084] Comparative Example 18 refers to Example 14, except that the amount of modified titanium dioxide used is 30 parts.

[0085] Comparative Example 19 refers to Example 14, except that the amount of modified titanium dioxide used is 5 parts.

[0086] Comparative Example 20 refers to Example 14, except that no polyvinylidene chloride is added.

[0087] Experimental Example 3 Oxygen barrier performance test

[0088] The PVC decorative films prepared in Examples 14-19 and Comparative Examples 13-17 were tested according to the national standard GB / T 19789-2021 using a Jinan Lablight differential pressure gas permeameter (VAC-V3). The oxygen barrier properties of the decorative films were determined by the oxygen permeability. The test results are shown in Table 4.

[0089] Table 4 Oxygen barrier performance test of Examples 14-19 and Comparative Examples 14-20

[0090]

[0091] The results in Table 5 show that the addition of modified titanium dioxide in Comparative Example 14 has a significant effect on the oxygen barrier performance of the decorative film. Since the particle size of nano titanium dioxide is small, when added to the PVC matrix, its high specific surface area makes it evenly dispersed to form numerous tiny barriers, which increases the tortuosity and distance of oxygen diffusion when oxygen molecules diffuse in the decorative film, and increases the diffusion resistance. In addition, due to the particularity of nano titanium dioxide crystals, there are active sites on the crystal surface, which can physically adsorb oxygen molecules. After the oxygen molecules are adsorbed, their free diffusion is restricted, further improving the oxygen barrier performance of the decorative film. In Comparative Examples 15-17, the nano titanium dioxide obtained without process treatment has poor dispersion uniformity, and titanium dioxide agglomerates during the preparation process. The uniformity of dispersion in the matrix decreases while reducing the compatibility of nano-titanium dioxide with the matrix, resulting in an increase in oxygen permeability. The uniformly dispersed nano-titanium dioxide can build an effective gas diffusion barrier in the PVC decorative film. In addition, in a well-dispersed state, nano-titanium dioxide can fill the gaps between PVC molecular chains, acrylic resin and other components, reducing the free volume inside the material, making the molecular chains more tightly arranged and orderly, and utilizing the hydroxyl groups on the surface of nano-titanium dioxide to hydrogen bond with the PVC molecular chains and chemically react with the polar groups in the acrylic resin, thereby enhancing the stability and density of the entire decorative film system. In Comparative Examples 18-19, the amount of modified titanium dioxide used will affect the oxygen barrier of the decorative film. Performance, a small amount of modified titanium dioxide particles are dispersed in the decorative film system to play a physical barrier role, but excessive modified titanium dioxide, the particles begin to agglomerate, the formation of agglomerates reduces the effective barrier area, forming larger defects and gaps in the decorative film, allowing oxygen to quickly penetrate, and the agglomerates destroy the original tight structure of the material, weakening the synergistic effect with other components, making it easier for oxygen to penetrate the decorative film, and the oxygen permeability increases; in Comparative Example 20, polyvinylidene chloride is not added, and the barrier performance of the decorative film is reduced. Since the molecular structure of polyvinylidene chloride contains a large number of chlorine atoms, the intermolecular force is enhanced, and the tight molecular structure formed limits the diffusion path of oxygen molecules. At the same time, polyvinylidene chloride has a lower The crystallinity of the nano-titanium dioxide is high, and its amorphous region and crystalline region are intertwined, which further hinders the penetration of oxygen. In addition, polyvinylidene chloride molecules can be adsorbed on the surface of nano-titanium dioxide to form an organic-inorganic hybrid structure. This structure not only makes the dispersion of nano-titanium dioxide in the PVC matrix more uniform and reduces agglomeration, but also constructs a more complex oxygen diffusion barrier inside the decorative film, significantly reducing the oxygen permeability. In summary, by adding modified titanium dioxide, modifying the nano-titanium dioxide and dispersing it, the dispersion uniformity of modified titanium dioxide in the matrix is ​​improved, and the dosage is controlled, so that the structure of the decorative film is more compact, and the organic-inorganic hybrid structure formed by the coordinated use of polyvinylidene chloride further improves the oxygen barrier performance of the decorative film.

[0092] Embodiment 20 is the same as embodiment 1;

[0093] Examples 21-24 refer to the preparation method and parameter conditions of Example 20, and the differences are shown in Table 5.

[0094] Comparative Example 21 refers to Example 20, except that no acrylic resin is used.

[0095] Comparative Example 22 refers to Example 20, except that the acrylic resin is sprayed on the surface of the decorative film by a spraying method.

[0096] Comparative Example 23 refers to Example 20, except that no perfluorooctyl ethyl acrylate is added to the acrylic resin.

[0097] Comparative Example 24 refers to Example 20, except that no acrylic resin is added and only an equal amount of perfluorooctyl ethyl acrylate is added during the melting process.

[0098] Comparative Example 25 refers to Example 20, except that the amount of acrylic resin used is 50 parts.

[0099] Comparative Example 26 refers to Example 20, except that the amount of acrylic resin used is 5 parts.

[0100] Comparative Example 27 refers to Example 20, except that the molecular weight of the acrylic resin is controlled to be 200,000.

[0101] Comparative Example 28 refers to Example 20, except that the terminal olefin polysiloxane is not used to modify the PVC.

[0102] Experimental Example 4 Water Vapor Barrier Capacity Test

[0103] The PVC decorative films prepared in Examples 20-24 and Comparative Examples 21-28 were tested using a Jinan Lablight differential pressure gas permeameter (VAC-V3) according to the national standard GB / T 1037-2021. The water vapor barrier properties of the decorative films were determined by the water vapor permeability. The test results are shown in Table 5.

[0104] Table 5 Water vapor barrier performance test of Examples 20-24 and Comparative Examples 21-28

[0105]

[0106] From the results in Table 6, it can be seen that the water vapor permeability of the decorative films obtained by not adding acrylic resin and adding acrylic resin without fluorine-containing monomer in Comparative Examples 21 and 23 is significantly improved compared with Examples 20-24. Since the introduction of fluorine-containing monomers will change the interaction between acrylic resin molecules, the special properties of CF bonds are used to make the interaction between resin molecules stronger and the molecular chains more closely arranged. In addition, the presence of fluorine-containing acrylic resin helps to better disperse and arrange other components, reduce the pores and defects inside the material, and thus reduce the permeation channels of water vapor. At the same time, fluorine atoms have extremely high electronegativity and small atomic radius, and the bond energy of CF bonds is large and the bond length is short, so that the fluorine-containing acrylic resin has extremely low surface energy. During the calendering process, fluorine atoms are enriched on the surface of the decorative film to form a fluorine atom layer with low surface energy, which avoids the interaction between water molecules and the resin and effectively prevents the penetration of water vapor. In Comparative Example 22, the acrylic resin layer is introduced by spraying, and the resulting decorative film has poor hydrophobic effect. It is difficult to ensure that the fluorine-containing coating is completely evenly distributed on the surface of the decorative film by the spraying method. In addition, the sprayed acrylic resin and the PVC decorative film matrix have poor compatibility, resulting in a decrease in the bonding ability and affecting the service life. In Comparative Example 24, the addition of fluorine-containing monomers may interfere with the synergistic effect between other components. Due to the special structure of fluorine-containing monomers, direct addition may change the regularity of the polymer molecular chain, causing the molecular chain arrangement to be disordered and reducing the crystallinity. , reducing the intermolecular force and the overall mechanical properties. In addition, the fluorinated monomer reacts chemically with the toughening agent, reducing the compatibility and dispersion uniformity between the components, resulting in stress concentration and poor mechanical properties. In comparative examples 25-27, the changes in the amount and molecular weight of the acrylic resin have a significant impact on the barrier properties of the decorative film. Excessive acrylic resin molecular weight leads to poor system fluidity, increased internal defects, and affected surface fluorine atom distribution, resulting in reduced water vapor barrier capacity. When the amount of acrylic resin is low, it cannot effectively cooperate with other components to fill the voids inside the material, and it is difficult to form a continuous and complete barrier layer at the interface, resulting in reduced water vapor barrier capacity. When the amount of acrylic resin is too much, the molecular chain is excessively The free volume between molecules increases, forming some larger gaps or channels, providing a path for water vapor molecules to penetrate. In addition, the excessive amount of acrylic resin causes changes in the internal structure of the material, resulting in phase separation, destroying the originally stable and dense microstructure, reducing the mechanical properties and affecting the water vapor barrier properties. In Comparative Example 28, the introduced silane group has low surface energy characteristics, changes the surface properties of the PVC molecular chain, reduces the polarity of the material surface, reduces the interaction between water molecules and the material surface, and can form a relatively hydrophobic "shell". It is difficult for water molecules to bind tightly to the material surface, but form a larger contact angle on the surface. At the same time, siloxane improves the heat resistance of the decorative film and synergistically reduces the water vapor permeability.In summary, by introducing acrylic resin prepared from fluorine-containing monomers, controlling the amount and molecular weight of acrylic resin, changing the addition method of acrylic resin, and coordinating the modification effect of terminal olefin polysiloxane, the water vapor barrier capacity of the decorative film can be improved. ;

[0107] 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 PVC decorative film production process, characterized in that: The preparation of the PVC decorative film comprises the following steps: The modified titanium dioxide is added to the modified PVC, acrylic resin, polyvinylidene chloride, toughening agent and additives by step-by-step mixing and mixing, and the mixture is stirred and mixed to obtain a rubber compound; the rubber compound is melt-extruded to obtain a PVC mixture; The PVC mixture is calendered by a three-stage calendering method to obtain a calendered PVC; the calendered PVC is subjected to drawing and embossing treatment to obtain a film material; the film material is cooled and curled to obtain the PVC decorative film; The modified PVC is prepared by swelling PVC resin and modifying it with terminal olefin-based polydimethylsiloxane; The modified titanium dioxide is obtained by modifying nano titanium dioxide by ultrasound, centrifugation and methacryloxypropyltrimethoxysilane; The acrylic resin is obtained by initiating polymerization of methacrylate, ethyl acrylate and perfluorooctyl ethyl acrylate; The toughening agent is obtained by polymerization of the terminal olefin polydimethylsiloxane, maleic anhydride, methacrylate and styrene; The additives include zinc stearate, antioxidant 1010, calcium carbonate and dioctyl phthalate.

2. The process for producing a PVC decorative film according to claim 1, characterized in that: The preparation of the modified PVC comprises the following steps: The PVC resin is crushed to obtain resin particles, and vacuum dried at 100° C. for 5 hours to obtain PVC particles; 90-110 parts of the PVC particles are added to tetrahydrofuran to dissolve, and stirred to obtain swollen PVC; 10-20 parts of the terminal olefin polydimethylsiloxane are added to the tetrahydrofuran to dissolve to obtain a dissolving solution; the dissolving solution is slowly added to the swollen PVC to obtain a mixed system; the mixed system is heated, 8 parts of dibenzoyl peroxide are added, and a reaction system is obtained by modification reaction; the reaction system is added to a methanol solution, filtered, washed, and vacuum dried to obtain the modified PVC.

3. The process for producing a PVC decorative film according to claim 2, characterized in that: The temperature of the modification reaction is 80-100° C.; the time of the modification reaction is 6-8 hours.

4. The process for producing a PVC decorative film according to claim 1, characterized in that: The preparation of the modified titanium dioxide comprises the following steps: Dissolving the methacryloxypropyltrimethoxysilane in a 95% ethanol solution, adding acetic acid to adjust the pH of the system to 3, and stirring for 2 hours to obtain a modifier solution; Slowly adding the nano titanium dioxide into an anhydrous ethanol solution to obtain a suspension; The suspension is subjected to ultrasonic treatment to obtain a treatment liquid; the treatment liquid is centrifuged for 10 minutes and vacuum dried to obtain treatment particles; the treatment particles are slowly added to the modifier solution, and the modification reaction is carried out at 500 rpm and 60-80° C. for 1-3 hours, and the modified titanium dioxide is obtained by drying and grinding.

5. The process for producing a PVC decorative film according to claim 4, characterized in that: The frequency of the ultrasonic treatment is 40-70kHz; the time of the ultrasonic treatment is 20-40min; the mass ratio of the nano titanium dioxide to the methacryloxypropyltrimethoxysilane is 8-12:

1.

6. The process for producing a PVC decorative film according to claim 1, characterized in that: The preparation of the acrylic resin comprises the following steps: 30 parts of the methacrylate, 20 parts of the ethyl acrylate and 5-15 parts of the perfluorooctyl ethyl acrylate are mixed, and stirred at 200 rpm for 1 hour to obtain a mixed system; toluene is added to a flask, nitrogen is replaced, and the mixed system is slowly added dropwise, and stirred for 30 minutes to obtain a reaction substrate; 3 parts of benzoyl peroxide are dissolved in toluene to obtain an initiator solution; the reaction substrate is heated to 70-90° C., the initiator solution is slowly added to the reaction substrate, the temperature is maintained at 200 rpm, the reaction is performed for 2-6 hours, and dodecyl mercaptan is added to control the molecular weight to 50,000-100,000 to obtain the acrylic resin.

7. The process for producing a PVC decorative film according to claim 1, characterized in that: The preparation of the toughening aid comprises the following steps: 10 parts of nonylphenol polyoxyethylene ether are added into deionized water, and stirred to dissolve to obtain an emulsion; 45-60 parts of the terminal olefin polydimethylsiloxane are slowly added dropwise into the emulsion, and stirred to disperse; dibenzoyl peroxide is then slowly added, and the temperature is raised to react to obtain latex particles; 5-15 parts of maleic anhydride, 24 parts of methacrylate, and 16 parts of styrene are added into the latex particles, and stirred at 400 rpm for 30 minutes to obtain a mixed system; 5 parts of azobisisobutyronitrile are added to the mixed system, and polymerization reaction is carried out at 80-100° C. for 2-5 hours to obtain a reaction product; a calcium chloride solution is added to the reaction product, and the product is separated and centrifuged, and washed and dried to obtain the toughening agent.

8. The process for producing a PVC decorative film according to claim 1, characterized in that: The three-stage calendering method includes: the first stage calendering temperature is 160-165°C, and the calendering roller speed ratio is 1.2-1.3; the second stage calendering temperature is 170-175°C, and the calendering roller speed ratio is 1.3-1.4; the third stage calendering temperature is 155-160°C, and the calendering roller speed ratio is 1.4-1.

5.

9. The process for producing a PVC decorative film according to claim 1, characterized in that: The PVC decorative film comprises 80-100 parts of the modified PVC, 10-25 parts of the acrylic resin, 10 parts of the polyvinylidene chloride, 8-20 parts of the toughening aid and 8-20 parts of modified titanium dioxide.

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