A PVC resin composition for surface coating, its preparation method and application

Abstract

This application discloses a PVC resin composition for surface coating, its preparation method, and its application, belonging to the field of polymer materials technology. The composition comprises the following components by weight: 100 parts of polyvinyl chloride resin; 2-5 parts of ASA adhesive powder; 3-6 parts of ionic liquid; 0.5-2 parts of lubricant; 1.5-2 parts of processing aid; 3-5 parts of heat stabilizer; and 3-8 parts of impact modifier. The ionic liquid is selected from at least one of 1-hexyl-3-methylimidazolium tetrafluoroborate and 1-(3-sulfopropyl)caprolactam-p-toluenesulfonate. The ASA adhesive powder has a core-shell structure, with the core being butyl acrylate copolysilicon and the shell being SAN. This application, through the compounding and synergistic effect of a specific ionic liquid and ASA adhesive powder, enables the resulting resin composition to simultaneously achieve excellent comprehensive properties such as strong coating adhesion, high surface smoothness, and good high-temperature dimensional stability when used for coating the surface of a substrate film, effectively solving the technical problem that traditional PVC coating materials cannot simultaneously achieve multiple key properties.

Description

Technical Field

[0001] This application relates to the field of polymer materials, and more specifically, to a PVC resin composition for surface coating, its preparation method, and its application. Background Technology

[0002] Surface-coated functional films are important materials widely used in decoration, packaging, electronics, and other fields. Their conventional manufacturing process involves first preparing or selecting a substrate film with good mechanical strength and dimensional stability (such as polyethylene terephthalate (PET), biaxially oriented polypropylene (BOPP), polycarbonate (PC), etc.). Then, a liquid coating containing polyvinyl chloride (PVC) resin and other functional additives is applied to its surface using processes such as roll coating, blade coating, or lamination, forming a composite functional film that combines the support of the substrate with the surface properties of PVC. These films are often used in applications requiring specific feel, gloss, weather resistance, or printability, such as decorative panels, flexible signage, and touchscreen surfaces.

[0003] However, this traditional "substrate + coating" approach faces a series of long-standing technical bottlenecks in achieving high-performance coating: Insufficient adhesion between coating and substrate: The interfacial bonding between the coating and heterogeneous substrates (such as PET and BOPP) is a key challenge; the surface energy, polarity, and coefficient of thermal expansion of the two are significantly different, making it difficult to form a strong bond through physical adsorption alone. During subsequent processing (such as thermal lamination and die-cutting) or use, changes in temperature and humidity, as well as stress, can easily lead to decreased coating adhesion, edge lifting, or even complete peeling, seriously affecting product reliability and service life.

[0004] Surface quality and flatness defects: To improve the impact resistance of PVC coatings, impact modifiers such as methyl methacrylate-butadiene-styrene copolymer (MBS) are often added. However, these modifiers have poor compatibility with the PVC matrix or migrate and aggregate during the coating curing process, which can lead to defects such as "orange peel", pitting, and uneven gloss on the coating surface, affecting the high-gloss appearance and feel of the final product.

[0005] Poor dimensional stability during high-temperature processing: Coated products often need to undergo subsequent high-temperature processes such as hot pressing, lamination, and drying. Due to the relatively low heat distortion temperature of PVC resin itself, and the presence of small molecule plasticizers further reducing its modulus at high temperatures, the coating is prone to softening, creep, or even shrinkage when heated.

[0006] Therefore, there is an urgent need in the field to develop a PVC resin composition specifically for surface coating. Summary of the Invention

[0007] This application provides a PVC resin composition for surface coating, its preparation method and application, which can simultaneously meet the comprehensive requirements of strong coating dehydration adhesion, low impurities, good flatness and no deformation or shrinkage during high-temperature processing, thereby significantly improving the application performance of PVC materials in substrate film surface coating.

[0008] In a first aspect, this application provides a PVC resin composition comprising the following components in parts by weight: 100 parts of polyvinyl chloride resin; 2-5 parts of ASA adhesive powder; 3-6 parts of ionic liquid; Lubricant 0.5-2 parts; Processing aids 1.5-2 parts; 3-5 parts heat stabilizer; 3-8 parts of impact modifier; The ionic liquid is selected from at least one of 1-hexyl-3-methylimidazolium tetrafluoroborate and 1-(3-sulfopropyl)caprolactam p-toluenesulfonate; the ASA rubber powder has a core-shell structure, with the core being butyl acrylate copolymer silicon and the shell being SAN, and the rubber particle size being 120-200 nm.

[0009] Optionally, the ionic liquid is composed of 1-hexyl-3-methylimidazolium tetrafluoroborate and 1-(3-sulfopropyl)caprolactam p-toluenesulfonate.

[0010] Optionally, the weight ratio of 1-hexyl-3-methylimidazolium tetrafluoroborate and 1-(3-sulfopropyl)caprolactam p-toluenesulfonate is 0.5-1:2.5-5.

[0011] Optionally, the processing aid is a methyl methacrylate-butyl acrylate copolymer.

[0012] Optionally, the impact modifier is a methyl methacrylate-butadiene-styrene copolymer.

[0013] Optionally, the lubricant is one or more of polyethylene wax and stearic acid.

[0014] Optionally, the heat stabilizer is one or more of organotin stabilizers, calcium-zinc stabilizers, zinc laurate, and barium laurate.

[0015] Secondly, this application provides the use of the PVC resin composition as described in the first aspect in the coating process of a substrate film surface.

[0016] Thirdly, this application provides a method for preparing the PVC resin composition as described in the first aspect, comprising the following steps: S1: Mix polyvinyl chloride resin, heat stabilizer, processing aid, impact modifier, and ASA adhesive powder in a high-speed mixer at room temperature for 5-10 minutes; S2: Add ionic liquid and heat to 105-115℃, then mix at high speed for 8-12 minutes. S3: Add lubricant, continue mixing for 2-5 minutes, and cool to below 40°C; S4: The mixture is melt-plasticized by a twin-screw extruder at an extrusion temperature of 160-180℃ to obtain the PVC resin composition.

[0017] In summary, this application includes at least one of the following beneficial technical effects: 1. Excellent coating adhesion and interfacial properties: By introducing a specific structure of ionic liquid (1-hexyl-3-methylimidazolium tetrafluoroborate and / or 1-(3-sulfopropyl)caprolactam p-toluenesulfonate) and core-shell ASA adhesive powder (SAN shell), the strong polarity and interfacial wetting ability of the ionic liquid and the compatibilizing and toughening effects of the ASA adhesive powder produce a synergistic effect, which significantly enhances the interfacial bonding force between the PVC resin composition and substrate films such as PET. 2. Excellent surface smoothness and high gloss appearance: The ionic liquid can effectively improve the rheology and leveling of the resin melt, and together with the uniform dispersion of ASA adhesive powder in the matrix, the coating surface formed by this composition is extremely smooth and dense. 3. Outstanding high-temperature dimensional stability: The selected ionic liquid can form a physical-chemical cross-linking network in the PVC matrix and interact with the ASA adhesive powder, thereby significantly improving the thermomechanical properties and heat creep resistance of the material. This makes the coating exhibit excellent resistance to deformation and shrinkage during subsequent high-temperature processing. Detailed Implementation

[0018] The present invention will now be described in detail through embodiments. It should be noted that the following embodiments are only for further illustration of the present invention and should not be construed as limiting the scope of protection of the present invention. Non-essential improvements and adjustments made by those skilled in the art based on the above description of the present invention still fall within the scope of protection of the present invention.

[0019] Unless otherwise specified, the experimental procedures used in the following examples are all standard laboratory methods.

[0020] Unless otherwise specified, all experimental materials and reagents used can be purchased through commercial channels.

[0021] Example 1 A PVC resin composition for surface coating comprises the following components in parts by weight: 100 parts of polyvinyl chloride resin (SG-5 type); 1.8 parts of methyl methacrylate-butyl acrylate copolymer (ACR-P20); 5 parts of methyl methacrylate-butadiene-styrene copolymer (MBS-726); 4 parts of calcium-zinc stabilizer; and 1.2 parts of lubricant (polyethylene wax and stearic acid compounded in a 1:1 mass ratio).

[0022] Its preparation method includes the following steps: S1: Add polyvinyl chloride resin, calcium-zinc stabilizer, methyl methacrylate-butyl acrylate copolymer, and methyl methacrylate-butadiene-styrene copolymer to a high-speed mixer and mix for 8 minutes at 800 rpm at room temperature; S2: Slowly heat to 110℃, and continue mixing at high speed for 10 minutes at this temperature; S3: Add lubricant, continue mixing for 3 minutes, then stir and cool the material to below 35°C; S4: The cooled mixture is melt-plasticized through a co-rotating twin-screw extruder to obtain the PVC resin composition; the temperatures of each section of the extruder are set to 160℃, 165℃, 170℃, 175℃, 175℃, and 170℃, and the die head temperature is 170℃.

[0023] Example 2

[0024] A PVC resin composition for surface coating comprises the following components in parts by weight: 100 parts of polyvinyl chloride resin; 3 parts of ASA adhesive powder (core is butyl acrylate copolysilicon, shell is SAN, average rubber particle size is 150nm, SX006); 3 parts of ionic liquid (1-hexyl-3-methylimidazolium tetrafluoroborate); 1.8 parts of methyl methacrylate-butyl acrylate copolymer (ACR-P20); 5 parts of methyl methacrylate-butadiene-styrene copolymer (MBS-726); 4 parts of calcium-zinc stabilizer; and 1.2 parts of lubricant (polyethylene wax:stearic acid = 1:1).

[0025] Its preparation method includes the following steps: S1: Add polyvinyl chloride resin, calcium-zinc stabilizer, methyl methacrylate-butyl acrylate copolymer (ACR-P20), methyl methacrylate-butadiene-styrene copolymer (MBS-726), and ASA adhesive powder (SX006) into a high-speed mixer and mix at 800 rpm for 8 minutes at room temperature to make the solid components initially uniform. S2: Add ionic liquid (1-hexyl-3-methylimidazolium tetrafluoroborate) to the mixture in step S1, then slowly heat to 110°C, and continue high-speed mixing at this temperature for 10 minutes to allow the ionic liquid to fully wet, disperse and interact with the other components. S3: Add lubricant (a mixture of polyethylene wax and stearic acid in a mass ratio of 1:1), continue mixing for 3 minutes, then stir and cool the material to below 35°C to obtain the premix. S4: The cooled premixed material is melted and plasticized in a co-rotating twin-screw extruder. The temperatures of each section of the extruder are set to 160℃, 165℃, 170℃, 175℃, 175℃, and 170℃, and the die head temperature is 170℃. After extrusion, traction, and pelletizing, the PVC resin composition for surface coating is obtained.

[0026] Example 3

[0027] A PVC resin composition for surface coating, wherein the ionic liquid is 3 parts of 1-(3-sulfopropyl)caprolactam p-toluenesulfonate, and the remaining components are the same as in Example 2.

[0028] The preparation method is the same as in Example 2.

[0029] Example 4

[0030] A PVC resin composition for surface coating, wherein the ionic liquid is 1 part of 1-hexyl-3-methylimidazolium tetrafluoroborate and 2 parts of 1-(3-sulfopropyl)caprolactam p-toluenesulfonate, and the remaining components are the same as in Example 2.

[0031] The preparation method is the same as in Example 2.

[0032] Example 5

[0033] A PVC resin composition for surface coating, wherein the ionic liquid is 1 part 1-ethyl-3-methylimidazolium tetrafluoroborate and 2 parts 1-(3-sulfopropyl)caprolactam p-toluenesulfonate, and the remaining components are the same as in Example 2.

[0034] The preparation method is the same as in Example 2.

[0035] Example 6

[0036] A PVC resin composition for surface coating, comprising ASA adhesive powder (core of butyl acrylate copolysilicon, shell of MMA, average rubber particle size of 120 nm, 65XC1), and other components as in Example 4.

[0037] Performance Evaluation

[0038] The PVC resin compositions prepared in Examples 1-6 were used as coating materials and coated on the surface of a corona-treated PET substrate (125 μm thick). After drying and setting for 3 min, a coating with a dry film thickness of about 20 μm was formed. The coating film was then subjected to the following performance tests, and the results are shown in Table 1.

[0039] 1. Coating adhesion Test method: Perform the cross-cut test according to ASTM D3359-23 standard (Method B) using a 6-blade cutter with a 1mm spacing. Peel the coating using 3M 610 tape and grade it according to the area of ​​coating peeling (0B-5B, 5B being the best).

[0040] 2. Surface roughness Test method: Using a stylus-type surface profilometer, referring to the ISO 4287 standard, the arithmetic mean roughness Ra was measured at 5 random locations on the coated surface, and the average value was taken.

[0041] 3. Heat shrinkage rate at 140℃ Test method: Cut a 100mm×100mm sample from the coated film, lay it flat in a 140℃ forced-air oven for 30 min without tensile constraints; after cooling to room temperature, accurately measure the dimensional changes in the longitudinal (MD) and transverse (TD) directions, and calculate the heat shrinkage rate.

[0042] Table 1 Test Project Coating adhesion (grade) Surface roughness Ra (μm) MD / TD (%) heat shrinkage rate at 140℃ Example 1 2B 0.28 3.5 / 3.7 Example 2 4B 0.16 1.9 / 2.0 Example 3 5B 0.13 1.2 / 1.3 Example 4 5B 0.08 0.8 / 0.9 Example 5 3B 0.20 2.3 / 2.5 Example 6 4B 0.15 1.3 / 1.4 Results analysis: Compared to Example 1 without added functional components, Examples 2-6 of this application significantly and synergistically improve the overall performance of the material in surface coating applications by introducing specific ionic liquids and ASA adhesive powder, specifically as follows: 1. Ionic liquids provide polarity and interfacial wetting, while ASA powder (SAN shell) enhances interfacial compatibility and cohesion; Examples 3 and 4 achieve 5B, exhibiting excellent coating peel resistance. 2. Ionic liquids improve melt flow and leveling properties, and when combined with ASA adhesive powder for uniform dispersion, the coating surface becomes more delicate; Example 4 shows Ra as low as 0.08 μm, resulting in a smooth and glossy appearance; 3. The physical-chemical cross-linking network formed by the ionic liquid in the system significantly improves the heat resistance of the coating material; the heat shrinkage rate of Example 4 at 140°C for 30 minutes is only 0.8-0.9%, which is much lower than that of Example 1, achieving the goal of "no deformation and no shrinkage during high-temperature processing"; 4. Example 4 showed the best performance in adhesion, surface smoothness, and thermal shrinkage, demonstrating a significant synergistic effect in performance enhancement among the dual ionic liquid system and ASA adhesive powder. In contrast, the performance of Example 5 declined significantly, highlighting the importance of the specific ionic liquid structure selected in this application. Although the adhesion and heat resistance of Example 6 were acceptable, the processability and surface smoothness deteriorated, demonstrating the necessity of selecting SAN shell ASA adhesive powder in this system to obtain the best overall processing and application performance.

[0043] In summary, the PVC resin composition provided in this application successfully solves the technical contradiction that traditional materials struggle to achieve high adhesion, high flatness, and high dimensional stability in surface coating applications.

[0044] The foregoing examples are merely illustrative, used to explain some features of the method described in this invention. The appended claims are intended to claim the broadest possible scope, and the embodiments presented herein are merely illustrative of selected implementations based on combinations of all possible embodiments. Therefore, the applicant intends that the appended claims are not limited by the selection of examples illustrating the features of the invention. Some numerical ranges used in the claims also include sub-ranges within them, and variations within these ranges should also be interpreted as being covered by the appended claims where possible.

Claims

1. A PVC resin composition for surface coating, characterized in that, The components include the following parts by weight: 100 parts of polyvinyl chloride resin; 2-5 parts of ASA adhesive powder; 3-6 parts of ionic liquid; Lubricant 0.5-2 parts; Processing aids 1.5-2 parts; Heat stabilizer 3-5 parts; 3-8 parts of impact modifier; The ionic liquid is selected from at least one of 1-hexyl-3-methylimidazolium tetrafluoroborate and 1-(3-sulfopropyl)caprolactam p-toluenesulfonate; the ASA rubber powder has a core-shell structure, with the core being butyl acrylate copolymer silicon and the shell being SAN, and the rubber particle size being 120-200 nm.

2. The PVC resin composition according to claim 1, characterized in that, The ionic liquid is composed of 1-hexyl-3-methylimidazolium tetrafluoroborate and 1-(3-sulfopropyl)caprolactam p-toluenesulfonate.

3. The PVC resin composition according to claim 2, characterized in that, The weight ratio of 1-hexyl-3-methylimidazolium tetrafluoroborate and 1-(3-sulfopropyl)caprolactam p-toluenesulfonate is 0.5-1:2.5-5.

4. The PVC resin composition according to claim 1, characterized in that, The processing aid is a methyl methacrylate-butyl acrylate copolymer.

5. The PVC resin composition according to claim 1, characterized in that, The impact modifier is a methyl methacrylate-butadiene-styrene copolymer.

6. The PVC resin composition according to claim 1, characterized in that, The lubricant is one or more of polyethylene wax and stearic acid.

7. The PVC resin composition according to claim 1, characterized in that, The heat stabilizer is one or more of organotin stabilizers, calcium-zinc stabilizers, zinc laurate, and barium laurate.

8. The use of a PVC resin composition as described in any one of claims 1-7 in the surface coating process of a substrate film.

9. A method for preparing a PVC resin composition according to any one of claims 1-7, characterized in that, Includes the following steps: S1: Mix polyvinyl chloride resin, heat stabilizer, processing aid, impact modifier, and ASA adhesive powder in a high-speed mixer at room temperature for 5-10 minutes; S2: Add ionic liquid and heat to 105-115℃, then mix at high speed for 8-12 minutes. S3: Add lubricant, continue mixing for 2-5 minutes, and cool to below 40°C; S4: The mixture is melt-plasticized by a twin-screw extruder at an extrusion temperature of 160-180℃ to obtain the PVC resin composition.