Anti-reflection and stiffness-increasing master batch for casting polypropylene film and preparation process of anti-reflection and stiffness-increasing master batch

Abstract

The invention relates to the technical field of polypropylene films, in particular to an anti-reflection and stiffness-increasing master batch for a casting polypropylene film and a preparation process thereof.The anti-reflection and stiffness-increasing master batch is at least prepared from, by weight, 85-95 parts of thermoplastic resin, 1-10 parts of third-generation sorbitol, 0.5-1 part of dispersing agent and 0.1-0.5 part of antioxidant. The master batch with obvious anti-reflection and stiffness-increasing effects is prepared at lower raw material cost, the preparation method is simple, and large-scale industrial production, popularization and application are easy to realize.

Description

Technical Field

[0001] The invention relates to the technical field of polypropylene films, in particular to an anti-transparency and stiffening masterbatch for cast polypropylene films and a preparation process thereof. Background Art

[0002] Polypropylene has low density, good heat and chemical resistance, is non-toxic and tasteless, has good surface gloss, and excellent comprehensive performance. It is widely used in the packaging of food, candy, cigarettes, tea, juice, milk, textiles, etc. At present, with the development of industry and the improvement of people's living standards, the performance requirements for packaging films are also increasing, especially the stiffness and transparency of the film are put forward higher requirements. For example, a Chinese patent application (authorization announcement number CN113861565B) discloses a stiffening masterbatch and its preparation method, polyolefin film and BOPP film, which mainly introduces cage-type polysilsesquioxane-g-graphene@SiO 2 The three-dimensional network structure is used as a stiffener, and a compatibilizer is added to form PP-compatibilizer-cage polysilsesquioxane-g-graphene@SiO after melt blending. 2 The composite system of polyolefin film stiffening masterbatch has high raw material cost and complicated preparation process, and needs to add about 10wt% to ensure the stiffness of polyolefin film, which has high use cost and is not easy to realize large-scale industrial production and application. Chinese patent application (publication number CN 111378224 A) discloses a cast polypropylene film anti-transmission and stiffening masterbatch and its preparation process, which uses nano barium sulfate treated with silane coupling agent and organic anti-transmission agent to improve transparency, but the anti-transmission effect needs to be further improved. Summary of the invention

[0003] In order to solve the above problems, the present invention provides a transparency-enhancing and stiffening masterbatch for cast polypropylene film. By optimizing the product formula system, a masterbatch with obvious transparency-enhancing and stiffening effects is prepared at a relatively low raw material cost. The preparation method is simple and easy to realize large-scale industrial production and popularize and apply.

[0004] On one hand, the present invention provides a transparency-enhancing and stiffening masterbatch for cast polypropylene film. The raw materials for its preparation include at least 85-95 parts of thermoplastic resin, 1-10 parts of third-generation sorbitol, 0.5-1 parts of dispersant and 0.1-0.5 parts of antioxidant, by weight.

[0005] As a preferred technical solution, the melt mass flow rate of the thermoplastic resin (tested at 230°C, 2.16kg, GB / T 3682-2018) is 7-20g / 10min, preferably 10-20g / 10min, and most preferably 17±3g / 10min.

[0006] As a preferred technical solution, the isotactic index (SH / T1774-2012) of the thermoplastic resin is ≥95.0wt%.

[0007] Preferably, the thermoplastic resin is an injection molding polypropylene resin, the melt mass flow rate (tested at 230°C, 2.16kg, GB / T 3682-2018) is 17.6g / 10min, the isotactic index (SH / T1774-2012) is 97.9wt%, and the product model is Gu Lei PPH-M17.

[0008] As a preferred technical solution, the melting point of the third generation sorbitol is ≥200°C; preferably, the melting point of the third generation sorbitol is ≥260°C.

[0009] As a preferred technical solution, the third-generation sorbitol is selected from at least one of 1,3:2,4-(4′-propylbenzylidene)-1-propyl sorbitol, 1,3:2,4-dibenzylidene sorbitol, 1,3:2,4-di(p-methylbenzylidene) sorbitol, and 1,3:2,4-di(3,4-dimethylbenzylidene)-D-sorbitol, preferably 1,3:2,4-di(3,4-dimethylbenzylidene)-D-sorbitol (CAS No.: 135861-56-2).

[0010] As an example, the third generation sorbitol is selected from BLK-7981, BLK-7988, BLK-7983, At least one of 3988, preferably BLK-7988 or 3988.

[0011] As a preferred technical solution, the dispersant is selected from at least one of a fatty acid dispersant and a wax dispersant.

[0012] Preferably, the fatty acid dispersant includes at least ethylene bisstearamide.

[0013] Preferably, the wax dispersant includes at least polyethylene wax.

[0014] As a preferred technical solution, the antioxidant is selected from at least one of hindered phenol antioxidants and phosphite antioxidants.

[0015] Preferably, the antioxidant is a combination of antioxidant 1010 and antioxidant 168, and the mass ratio of the antioxidant 1010 to the antioxidant 168 is 1:(1-3), preferably 1:2.

[0016] The anti-transmission masterbatch provided by the present invention is conducive to processing and crystallization by using an injection-molding polypropylene resin with a melt mass flow rate of 7-20g / 10min and an isotactic index of ≥95.0wt%. Further, the third-generation sorbitol with a melting point of ≥260°C is used as a nucleating agent, which has good compatibility with the polypropylene resin. Under the condition of the presence of a dispersant, the transparency, glossiness and physical and mechanical properties are significantly improved, ensuring the subsequent application effect. In particular, when the dispersant includes ethylene bis stearamide or polyethylene wax, the system dispersibility and the mechanical properties of the product are improved, and a plastic composite material with high stiffness, high strength and high toughness is subsequently prepared.

[0017] On the other hand, the present invention provides a method for preparing a transparency-enhancing and stiffening masterbatch for cast polypropylene film, which comprises at least the following steps: premixing third-generation sorbitol, a dispersant and an antioxidant to obtain a mixed powder; adding a thermoplastic resin and the mixed powder through two main feed ports of a twin-screw extruder, heating, melting and mixing, extruding and granulating, cooling and granulating, and drying to obtain the film.

[0018] As a preferred technical solution, the process parameters of the twin-screw extruder include: output 500-600kg / h; main engine speed 300-400r / min; extruder zone 1-6 temperature 190-200℃, 7-10 zone temperature 175-185℃, 11-15 zone temperature 150-170℃, head temperature 230-260℃, transition body temperature 230-260℃; filter mesh number 200-300 mesh, filter layer number 3-6 layers.

[0019] Preferably, the process parameters of the twin-screw extruder include: output 600kg / h; main engine speed 350r / min; extruder zone 1-6 temperature 190°C, 7-10 zone temperature 180°C, 11-15 zone temperature 160°C, head temperature 250°C, transition body temperature 250°C; filter mesh number 250 mesh, filter layer number 5 layers.

[0020] As a preferred technical solution, the pelletizing rotation speed is 2000-3000 rpm, preferably 2800 rpm.

[0021] The present invention optimizes the production process of anti-reflection masterbatch to achieve low-temperature production, so that the provided masterbatch has a whiter and more transparent appearance, a smaller and more uniform size, and a better dispersion effect when used on a film subsequently, effectively improving the appearance of the film and reducing the problem of color change.

[0022] The third aspect of the present invention provides an application of an anti-reflection and stiffening masterbatch for cast polypropylene film, which is applied to the preparation of cast polypropylene film products, wherein the addition amount of the anti-reflection and stiffening masterbatch for cast polypropylene film in the cast polypropylene film product is ≤5wt%.

[0023] The anti-reflection masterbatch provided by the invention is added in a cast polypropylene film system in an amount of ≤5wt%, which significantly improves the optical and mechanical properties of the cast polypropylene film, greatly reduces the use cost, and has extremely high market promotion value.

[0024] Beneficial Effects

[0025] 1. The present invention provides a masterbatch for cast polypropylene film to increase transparency and stiffness. By optimizing the product formula system, a masterbatch with obvious effects of increasing transparency and stiffness can be prepared at a relatively low raw material cost. The preparation method is simple and easy to realize large-scale industrial production and popularize and apply.

[0026] 2. The anti-reflection masterbatch provided by the present invention is advantageous for processing and crystallization by adopting an injection molding polypropylene resin having a melt mass flow rate of 7-20 g / 10 min and an isotactic index ≥ 95.0 wt%.

[0027] 3. The present invention adopts the third generation sorbitol with a melting point of ≥260°C as a nucleating agent, which has good compatibility with polypropylene resin. In the presence of a dispersant, the transparency, glossiness and physical and mechanical properties are significantly improved to ensure the subsequent application effect. In particular, when the dispersant includes ethylene bisstearamide or polyethylene wax, the system dispersibility and the mechanical properties of the product are improved, and a plastic composite material with high stiffness, high strength and high toughness is subsequently prepared.

[0028] 4. The present invention optimizes the production process of anti-reflection masterbatch to achieve low-temperature production, so that the provided masterbatch has a whiter and more transparent appearance, a smaller and more uniform size, and a better dispersion effect on the subsequent film, which effectively improves the appearance of the film and reduces the color change problem.

[0029] 5. The anti-reflection masterbatch provided by the present invention, when added in a cast polypropylene film system at a rate of ≤5wt%, significantly improves the optical and mechanical properties of the cast polypropylene film, greatly reduces the use cost, and has extremely high market promotion value. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a comparison chart of the stiffness of the cast polypropylene film products provided in Application Example 1 and the Application Control Example. The upper part of the figure is the cast polypropylene film product provided in the Application Control Example, and the lower part of the figure is the cast polypropylene film product provided in Application Example 1. DETAILED DESCRIPTION

[0031] Example 1-2, Comparative Example 1-2

[0032] On the one hand, Examples 1-2 and Comparative Examples 1-2 of the present invention provide a transparency-enhancing and stiffening masterbatch for cast polypropylene film. The formula is shown in Table 1 in parts by weight.

[0033] Table 1

[0034]

[0035] In Table 1: The model of the third generation sorbitol is 3988; the model of polyethylene wax is SX-110B, which comes from Guangzhou Bohan Chemical Co., Ltd.; the model of ethylene bisstearamide is Kao EBS; the composite antioxidant is composed of BASF 1010 and BASF 168 in a mass ratio of 1:2; the model of nano-silica is A200, which comes from Evonik Chemicals.

[0036] On the other hand, embodiments 1-2 and comparative examples 1-2 of the present invention provide a method for preparing a transparency-enhancing and stiffening masterbatch for cast polypropylene film, comprising the following steps: premixing third-generation sorbitol, a dispersant, and an antioxidant to obtain a mixed powder; weighing the thermoplastic resin and the mixed powder using a loss-in-weight scale (with an accuracy of one thousandth of a kilogram), adding them through two main feeding ports of a twin-screw extruder, heating, melting and mixing, extruding and granulating, cooling and pelletizing, and drying to obtain the film; the process parameters of the twin-screw extruder include: an output of 600kg / h; a main engine speed of 350r / min; the temperature of extruder zones 1-6 is 190°C, the temperature of zones 7-10 is 180°C, the temperature of zones 11-15 is 160°C, the head temperature is 250°C, and the transition body temperature is 250°C; the filter mesh number is 250 mesh, and the number of filter layers is 5; the pelletizing speed is 2800rpm.

[0037] Application Examples 1-2, Application Comparative Examples 1-2

[0038] Application Examples 1-2 and Comparative Examples 1-2 of the present invention provide a cast polypropylene film product, including a core layer, a heat sealing layer and a corona layer, wherein the core layer is in the middle, and the heat sealing layer and the corona layer are respectively on both sides of the core layer. See Table 2 for the formula.

[0039] Table 2

[0040]

[0041] The preparation method of the cast polypropylene film product is as follows: a cast polypropylene film anti-transparency and stiffening masterbatch is mixed with polypropylene to obtain a core layer material, and the core layer material, a heat sealing layer material, and a corona layer material are subjected to a cast film forming process to prepare a cast polypropylene film product with a three-layer structure of 35±5 μm thick.

[0042] Performance Testing

[0043] 1. The optical properties and mechanical properties of the cast polypropylene film products provided in the application examples and comparative examples were tested. The optical properties were tested in accordance with GB / T 2410, and the mechanical properties were tested in accordance with GB / T 1040. The test results are shown in Table 3.

[0044] Table 3

[0045]

[0046]

[0047] In Table 3: T: transmittance, H: haze, C: clarity, G: glossiness.

[0048] 2. Test the stiffness of the cast polypropylene film products provided in Example 1 and the comparative example. The results are shown in Figure 1 By comparison, it can be seen that adding the anti-reflection masterbatch provided in Example 1 to the polypropylene film can effectively improve the stiffness of the film.

Claims

1. A transparent and stiffening masterbatch for cast polypropylene film, characterized in that: The raw materials for its preparation at least include, by weight: 85-95 parts of thermoplastic resin, 1-10 parts of third-generation sorbitol, 0.5-1 parts of dispersant, and 0.1-0.5 parts of antioxidant.

2. The anti-transparency and stiffening masterbatch for cast polypropylene film according to claim 1, characterized in that: The melt mass flow rate of the thermoplastic resin is 7-20 g / 10 min.

3. The anti-transparency and stiffening masterbatch for cast polypropylene film according to claim 1, characterized in that: The isotactic index of the thermoplastic resin is ≥95.0 wt %.

4. The anti-transparency and stiffening masterbatch for cast polypropylene film according to claim 1, characterized in that: The melting point of the third generation sorbitol is ≥200°C.

5. The anti-transparency and stiffening masterbatch for cast polypropylene film according to claim 4, characterized in that: The third generation sorbitol is selected from at least one of 1,3:2,4-(4′-propylbenzylidene)-1-propyl sorbitol, 1,3:2,4-dibenzylidene sorbitol, 1,3:2,4-di(p-methylbenzylidene) sorbitol and 1,3:2,4-di(3,4-dimethylbenzylidene)-D-sorbitol.

6. The anti-transparency and stiffening masterbatch for cast polypropylene film according to claim 1, characterized in that: The dispersant is selected from at least one of a fatty acid dispersant and a wax dispersant.

7. The anti-transparency and stiffening masterbatch for cast polypropylene film according to claim 6, characterized in that: The fatty acid dispersant at least includes ethylene bisstearamide; the wax dispersant at least includes polyethylene wax.

8. The anti-transparency and stiffening masterbatch for cast polypropylene film according to claim 1, characterized in that: The antioxidant is selected from at least one of hindered phenol antioxidants and phosphite antioxidants.

9. A method for preparing an anti-transparency and stiffening masterbatch for cast polypropylene film according to any one of claims 1 to 8, characterized in that: At least the following steps are included: The third generation sorbitol, dispersant and antioxidant are premixed to obtain a mixed powder; the thermoplastic resin and the mixed powder are added through two main feeding ports of a twin-screw extruder, heated, melted and mixed, extruded into granules, cooled and granulated, and dried to obtain the product.

10. An application of the anti-transparency and stiffening masterbatch for cast polypropylene film according to any one of claims 1 to 8, characterized in that: The invention is applied to the preparation of cast polypropylene film products, wherein the addition amount of the anti-transparency and stiffness-enhancing masterbatch for cast polypropylene film in the cast polypropylene film product is less than or equal to 5wt%.

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