Formula and preparation method of low-cost easy-to-process matt weather-resistant PVC (polyvinyl chloride) hard film

Abstract

The invention relates to the technical field of manufacturing of hard matt PVC (polyvinyl chloride) films, in particular to a formula and a preparation method of a low-cost and easy-to-process matt weather-resistant PVC hard film. Comprising the following components in parts by weight: 80-95 parts of polyvinyl chloride (PVC) resin, 5-15 parts of extinction polyvinyl chloride resin, 1.5-2 parts of a methyl tin mercaptide stabilizer, 1-3 parts of epoxidized soybean oil, 1-3 parts of EVA resin, 4-6 parts of an ACR processing aid, 0.45-0.8 part of an external lubricant, 0.2-0.7 part of an antioxidant and 0.8-3 parts of an ultraviolet light absorber, the sum of the weight parts of the polyvinyl chloride resin and the extinction polyvinyl chloride resin is 100. According to the formula of the low-cost easily-processed matt weather-resistant PVC hard film and the preparation method of the matt weather-resistant PVC hard film, through the collaborative design of formula adjustment and equipment improvement, the problems that an existing PVC matt weather-resistant film is large in matt resin consumption, a weather-resistant agent is easy to separate out and the processing difficulty is high are solved, the low-cost and easily-processed film is achieved, and meanwhile the matt weather-resistant PVC hard film has the good matt weather-resistant performance. The delustering and weather-resistant properties are ensured.

Description

Technical Field

[0001] This invention relates to the field of rigid matte polyvinyl chloride film manufacturing technology, and particularly to a low-cost, easy-to-process matte weather-resistant rigid PVC film formulation and its preparation method. Background Technology

[0002] Due to its low gloss and soft texture, rigid PVC matte film is widely used in various decorative and packaging fields. In existing technologies, to achieve the dual requirements of low gloss and high weather resistance, the following solutions are typically adopted: increasing the amount of matting resin (or matting powder) and increasing the proportion of weather-resistant additives such as UV stabilizers, while using MBS resin as an impact modifier.

[0003] However, this approach has significant drawbacks: First, the high proportion of matting resin (usually ≥20 parts) leads to a substantial increase in raw material costs; second, excessive addition of UV stabilizers can easily cause precipitation problems, affecting the film's appearance and performance; third, MBS resin contains a large number of carbon-carbon double bonds, has high chemical activity, and is prone to photo-oxidation under light, reducing the film's weather resistance; fourth, the combination of a high proportion of matting resin and MBS resin results in poor melt flow during film processing, making it prone to molding defects and increasing processing difficulty.

[0004] To address the above problems, this invention proposes a low-cost, easy-to-process matte, weather-resistant rigid PVC film formulation and its preparation method. Summary of the Invention

[0005] The main objective of this invention is to provide a low-cost, easy-to-process matte, weather-resistant rigid PVC film formulation and its preparation method, which can effectively solve the problems in the background art.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A low-cost, easy-to-process matte, weather-resistant rigid PVC film formulation comprises the following components in parts by weight: 80-95 parts of polyvinyl chloride (PVC) resin 5-15 parts of matte polyvinyl chloride resin Methyl mercaptan stabilizer 1.5-2 parts, 1-3 parts of epoxidized soybean oil 1-3 parts of EVA resin ACR processing aid 4-6 parts, External lubricant 0.45–0.8 parts, Antioxidant 0.2–0.7 parts, 0.8–3 parts of ultraviolet absorber; The total weight of the polyvinyl chloride resin and the matte polyvinyl chloride resin is 100 parts.

[0007] Preferably, the VA content of the EVA resin is 28% to 33%.

[0008] Preferably, the external lubricant is composed of two components: 0.35 to 0.5 parts of stearic acid and 0.1 to 0.3 parts of polyethylene wax.

[0009] Preferably, the ultraviolet absorber is a benzotriazole.

[0010] Preferably, the ACR processing aid is a methyl methacrylate-ethyl acrylate copolymer.

[0011] A method for preparing a low-cost, easy-to-process matte, weather-resistant rigid PVC film includes the following steps: S1: Measure each raw material according to the formula; S2: Add PVC resin, matte polyvinyl chloride resin, methyl mercaptan stabilizer, epoxidized soybean oil, ACR processing aid, antioxidant, ultraviolet absorber and external lubricant to a hot mixer and mix for 6 to 15 minutes. S3: Transfer the mixture from step S2 into a cold mixer, add EVA resin, and continue mixing for 6–15 minutes; S4: The uniformly mixed material is pre-plasticized by shearing in a planetary screw extruder at 110-190℃ and then further plasticized in a two-roll open mill at 140-170℃. S5: The plasticized material is fed into a five-roll calender at 190–220℃ for calendering, then drawn out by a stretching machine, cooled and shaped, and wound and slit to obtain a matte, weather-resistant rigid PVC film; the last forming roll of the five-roll calender is a matte roll with a surface roughness Ra value of 0.25–0.35 μm. Preferably, the operating temperature of the hot mixer in step S2 is 90°C; and the operating temperature of the cold mixer in step S3 is 55°C.

[0012] Preferably, in step S4, the screw speed of the planetary screw extruder is 30-50 r / min, and the extrusion pressure is 15-25 MPa.

[0013] Preferably, the matte roller in step S5 is made by diamond sandblasting; the linear speed during calendering is 20-30 m / min; the cooling and shaping adopts a segmented cooling method, with the first segment cooling temperature at 80-100℃ and the second segment cooling temperature at 40-60℃.

[0014] Compared with the prior art, the present invention has the following beneficial effects: 1. Excellent processing performance: ACR processing aid and compound external lubricant work synergistically to improve material flowability, and together with matte rollers to eliminate water ripple defects, the processing is continuous and stable, with no molding failures; 2. Improved weather resistance: ACR processing aids replace MBS resin, and combined with the synergistic effect of benzotriazole UV absorbers and antioxidants, the weather resistance of the film is significantly better than that of existing technologies; 3. No risk of precipitation: The amount of ultraviolet absorber added is controlled at 0.8 to 3 parts, which is 30% to 60% less than that of existing technologies, fundamentally avoiding the problem of precipitation of weather-resistant additives; 4. Stable performance and low cost: The amount of matte polyvinyl chloride resin used is only 5 to 15 parts, and no additional matting powder is required, which reduces the raw material cost. The film gloss (45°) is ≤21, and the core performance meets the application requirements. Detailed Implementation

[0015] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0016] A low-cost, easy-to-process matte, weather-resistant PVC rigid film formulation, with the core components and their weight ranges as follows: Polyvinyl chloride (PVC) resin: 80-95 parts, as a film substrate, providing basic mechanical properties; Matting polyvinyl chloride resin: 5-15 parts, which works synergistically with PVC resin to achieve a matting effect, and the amount used is only 1 / 4 to 1 / 2 of that in the prior art; Methyl mercaptan stabilizer: 1.5–2 parts, to inhibit thermal degradation of PVC resin during processing; Epoxidized soybean oil: 1-3 parts, as a plasticizer to improve the flowability of materials during processing; EVA resin: 1-3 parts, VA content 28%-33%, synergistically improves film toughness with other components; ACR processing aid: 4-6 parts, specifically methyl methacrylate-ethyl acrylate copolymer, replacing traditional MBS resin; External lubricant: 0.45–0.8 parts, composed of 0.35–0.5 parts stearic acid and 0.1–0.3 parts polyethylene wax; Antioxidant: 0.2–0.7 parts, to inhibit the thermal oxidation reaction of resin; UV absorber: 0.8–3 parts, specifically benzotriazole, to improve the weather resistance of the film; Note: The total weight of polyvinyl chloride resin and matte polyvinyl chloride resin is fixed at 100 parts.

[0017] Component synergistic logic: ACR processing aids do not contain carbon-carbon double bonds and have a saturated chemical structure. When used to replace MBS resin, they fundamentally improve the weather resistance of films and improve the flowability of materials during processing. The synergistic effect of EVA resin and ACR processing aids compensates for the lack of toughness caused by the increase in ACR. The compound external lubricant reduces friction between materials and equipment through the synergistic effect of stearic acid and polyethylene wax, further optimizing processing performance; A low-gloss effect can be achieved by using a low amount of matte PVC resin in conjunction with the matte rollers of the subsequent calendering equipment, without the need to add additional matte powder.

[0018] A method for preparing a low-cost, easy-to-process matte, weather-resistant rigid PVC film includes the following steps: Step S1: Raw material measurement: Accurately measure each raw material component according to the weight ratio of the above formula to ensure that the ratio error is ≤ ±0.1 parts.

[0019] Step S2: Hot mixing: Add polyvinyl chloride resin, matte polyvinyl chloride resin, methyl mercaptan stabilizer, epoxidized soybean oil, ACR processing aid, antioxidant, ultraviolet absorber and compound external lubricant to a hot mixer in sequence, and mix at 90°C for 6 to 15 minutes to ensure that the materials are fully pre-dispersed.

[0020] Step S3: Cold mixing: The mixture from step S2 is fed into a cold mixer. The operating temperature of the cold mixer is controlled at 55°C. EVA resin is added, and mixing continues for 6 to 15 minutes until the material temperature drops to room temperature to avoid premature melting of the EVA resin, which would affect the uniformity of dispersion.

[0021] Step S4: Extrusion and Plasticization: The uniformly mixed material is fed into a planetary screw extruder. The extruder temperature is controlled at 110-190℃, the screw speed at 30-50 r / min, and the extrusion pressure at 15-25 MPa. After shearing and pre-plasticization, the material is extruded. The extruded material is then fed into a two-roll mill for further plasticization at 140-170℃ to ensure that the material is melted uniformly and free of particles.

[0022] Step S5: Calendering and Post-processing: The plasticized material is fed into a five-roll calender, with the calendering temperature controlled at 190–220℃ and the linear speed at 20–30 m / min. The last forming roll of the five-roll calender is a matte roll, which is made by diamond sandblasting and has a surface roughness Ra value of 0.25–0.35 μm. The calendered film is drawn out by a stretching machine and cooled and shaped using a segmented cooling method (first stage cooling temperature 80–100℃, second stage cooling temperature 40–60℃). Finally, it is wound up and slit to obtain the finished film.

[0023] Specifically, the last forming roll of the five-roll calender replaces the traditional mirror roll and is treated with full-surface sandblasting with diamond abrasive to form a uniform matte structure. This structure embosses the film surface during high-temperature calendering, which reduces the amount of matting resin used and eliminates the water ripple defects caused by increased ACR.

[0024] Example 1 A low-cost, easy-to-process matte, weather-resistant rigid PVC film formulation. Formulation composition (parts by weight): Polyvinyl chloride (PVC) resin: 90 parts; Matte polyvinyl chloride resin: 10 parts; Methyl mercaptan stabilizer: 2 parts; Epoxidized soybean oil: 2 parts; EVA resin (VA content 30%): 2 parts; ACR processing aid (methyl methacrylate-ethyl acrylate copolymer): 4 parts; Stearic acid: 0.35 parts; Polyethylene wax: 0.1 parts; Antioxidant: 0.3 parts; Benzotriazole UV absorber: 1.5 parts.

[0025] A method for preparing a low-cost, easy-to-process matte, weather-resistant rigid PVC film includes the following steps: S1: Accurately measure each raw material according to the above-mentioned weight proportions; S2: Add PVC resin, matte polyvinyl chloride resin, methyl mercaptan stabilizer, epoxidized soybean oil, ACR processing aid, antioxidant, ultraviolet absorber, stearic acid and polyethylene wax to a hot mixer and mix at 90°C for 10 minutes. S3: Transfer the hot-mixed material into a 55℃ cold mixer, add EVA resin, and continue mixing for 10 minutes until the material temperature drops to room temperature; S4: Feed the mixture into a planetary screw extruder, control the temperature at 150℃, the screw speed at 40r / min, and the extrusion pressure at 20MPa, and extrude it after shearing and pre-plasticizing. S5: The extruded material is fed into a two-roll open mill for further plasticization at 150°C; S6: The plasticized material is fed into a five-roll calender, with the calendering temperature controlled at 200℃ and the linear speed at 20m / min. It is then calendered into shape using a matte roller (Ra 0.3μm). S7: The formed film is cooled in sections (90°C for the first section and 50°C for the second section), stretched and drawn out, and then wound up and cut to obtain the finished product.

[0026] Comparative Example (Existing Technical Solution) 1. Formulation composition (by weight) Polyvinyl chloride (PVC) resin: 80 parts; Matte polyvinyl chloride resin: 20 parts; Methyl mercaptan stabilizer: 2 parts; ACR processing aid: 1.8 parts; MBS resin: 5 parts; Stearic acid: 0.35 parts; Polyethylene wax: 0.1 parts; Antioxidant: 0.3 parts; UV absorber: 2.5 parts.

[0027] 2. Preparation steps Measure each ingredient by weight and add it to a 90°C hot mixer and mix for 10 minutes. The mixture was pre-plasticized and extruded using a planetary screw extruder at 150℃ (40 r / min speed, 20 MPa pressure); After being plasticized by a 150°C two-roll open mill, the extruded material is fed into a five-roll calender (temperature 200°C, linear speed 20m / min), and the last forming roll is a mirror roll. The finished product is obtained after cooling, shaping, winding, and slitting.

[0028] Performance test comparison Results Analysis Example 1: By replacing MBS with ACR in the formulation and adding EVA resin, combined with the application of a matte roller in the preparation method, the film has lower gloss and better weather resistance while reducing the amount of matting resin and UV absorber. There is no precipitation of weathering agent, the processing is continuous and stable, and the raw material cost is reduced by 15% compared with the comparative example. It fully achieves the core goals of low cost, easy processing, matte and weather-resistant properties.

[0029] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A formulation for a low-cost, easily processed matte, weather-resistant rigid PVC film, characterized in that, Includes the following components by weight: 80-95 parts of polyvinyl chloride (PVC) resin 5-15 parts of matte polyvinyl chloride resin Methyl mercaptan stabilizer 1.5-2 parts, 1-3 parts of epoxidized soybean oil 1-3 parts of EVA resin ACR processing aid 4-6 parts, External lubricant 0.45–0.8 parts, Antioxidant 0.2–0.7 parts, 0.8–3 parts of ultraviolet absorber; The total weight of the polyvinyl chloride resin and the matte polyvinyl chloride resin is 100 parts.

2. The formulation of a low-cost, easily processed matte, weather-resistant rigid PVC film according to claim 1, characterized in that: The VA content of the EVA resin is 28% to 33%.

3. The formulation of a low-cost, easily processed matte, weather-resistant rigid PVC film according to claim 1, characterized in that: The external lubricant is composed of two components: 0.35 to 0.5 parts of stearic acid and 0.1 to 0.3 parts of polyethylene wax.

4. The formulation of a low-cost, easily processed matte, weather-resistant rigid PVC film according to claim 1, characterized in that: The ultraviolet absorber is a benzotriazole.

5. The formulation of a low-cost, easily processed matte, weather-resistant rigid PVC film according to claim 1, characterized in that: The ACR processing aid is a methyl methacrylate-ethyl acrylate copolymer.

6. A method for preparing a low-cost, easily processed matte, weather-resistant rigid PVC film according to any one of claims 1-5, characterized in that: Includes the following steps: S1: Measure each raw material according to the formula; S2: Add PVC resin, matte polyvinyl chloride resin, methyl mercaptan stabilizer, epoxidized soybean oil, ACR processing aid, antioxidant, ultraviolet absorber and external lubricant to a hot mixer and mix for 6 to 15 minutes. S3: Transfer the mixture from step S2 into a cold mixer, add EVA resin, and continue mixing for 6–15 minutes; S4: The uniformly mixed material is pre-plasticized by shearing in a planetary screw extruder at 110-190℃ and then further plasticized in a two-roll open mill at 140-170℃. S5: The plasticized material is fed into a five-roll calender at 190-220℃ for calendering and forming. After being drawn out by a stretching machine, cooled and shaped, and then wound and cut, a matte weather-resistant PVC rigid film is obtained. The last forming roll of the five-roll calender is a matte roll with a surface roughness Ra value of 0.25-0.35μm.

7. The method for preparing a low-cost, easily processed matte, weather-resistant rigid PVC film according to claim 6, characterized in that: In step S2, the operating temperature of the hot mixer is 90℃; in step S3, the operating temperature of the cold mixer is 55℃.

8. The method for preparing a low-cost, easily processed matte, weather-resistant rigid PVC film according to claim 6, characterized in that: In step S4, the screw speed of the planetary screw extruder is 30-50 r / min, and the extrusion pressure is 15-25 MPa.

9. The method for preparing a low-cost, easily processed matte, weather-resistant rigid PVC film according to claim 6, characterized in that: The matte roller mentioned in step S5 is made by diamond sandblasting; the linear speed during calendering is 20-30 m / min; the cooling and shaping adopts a segmented cooling method, with the first segment cooling temperature at 80-100℃ and the second segment cooling temperature at 40-60℃.

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