COP compatibilizer, preparation method and application of COP compatibilizer in multi-layer co-extruded film

Abstract

The invention relates to the technical field of functional materials, and particularly discloses a COP compatibilizer, a preparation method and application of the COP compatibilizer in a multi-layer co-extruded film. The COP compatibilizer is a grafted copolymer of anhydride functionalized COP and polyolefin grafted glycidyl ester; wherein the proportion of the COP chain segment is 30-50%, and the polyolefin grafted glycidyl ester comprises polypropylene glycidyl ester or polyethylene glycidyl ester. The COP compatibilizer provided by the invention can effectively improve the compatibility of COP with polypropylene and polyethylene, can significantly improve the mechanical properties of a film material when being used for preparing a co-extrusion multilayer film, can also be used as a bonding layer to improve the adhesiveness of a COP layer with PP and PE layers, and can also be blended with COP to serve as an inner layer to improve the heat sealing property of the COP as the inner layer.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of functional materials, and particularly discloses a COP compatibilizer, a preparation method thereof and application of the COP compatibilizer in a multilayer co-extrusion film. BACKGROUND

[0002] Cyclo-olefin polymer (COP) is an amorphous thermoplastic resin, which is prepared by using norbornene and its derivatives as main raw materials through ring-opening metathesis polymerization (ROMP) reaction. COP has high transparency, low water absorption, chemical resistance, thermal stability and good biocompatibility, and is widely used in the fields of optics, medicine and electronics.

[0003] The COP main chain is composed of five-membered rings and has large steric hindrance, which not only endows COP with excellent characteristics such as high transparency and low water absorption, but also has the disadvantage of poor toughness when used alone. Due to its unique chemical structure and nonpolar molecular chain characteristics, COP has poor compatibility with polyolefin compounds. Improving the compatibility of COP and polyolefin compounds becomes a key factor restricting the application and product development of COP.

[0004] At present, there is no related report on the method for improving the compatibility of COP and polyolefin compounds. Improving the compatibility of COP and polyolefin compounds can not only broaden the application field, but also develop more new products. Therefore, it is urgent to develop a preparation method of a COP compatibilizer to improve the compatibility of COP and PP and PE, and apply the COP compatibilizer to a multilayer co-extrusion film. SUMMARY

[0005] The application provides a COP compatibilizer which can effectively improve the compatibility of COP and polypropylene and polyethylene, can significantly improve the mechanical properties of a film material when used for preparing a co-extrusion multilayer film, can be used as an adhesive layer to improve the adhesion of a COP layer and a PP layer and a PE layer, and can be blended with COP as an inner layer to improve the heat sealing property of the COP as the inner layer.

[0006] The application is achieved by the following technical scheme. The COP compatibilizer is a graft copolymer of anhydride-functionalized COP and polyolefin grafted glycidyl ester, and the mass ratio of the anhydride-functionalized COP and the polyolefin grafted glycidyl ester is 3-5:5-7; wherein the COP segment accounts for 30-50%, and the polyolefin grafted glycidyl ester includes polypropylene glycidyl ester or polyethylene glycidyl ester.

[0007] In the present application, the anhydride-functionalized COP is obtained by catalytic hydrogenation after polymerization of 5-norbornene-2,3-dicarboxylic acid and norbornene or norbornene derivative, wherein the mass ratio of 5-norbornene-2,3-dicarboxylic acid to norbornene or norbornene derivative is 3-8:92-97. Specifically, the norbornene derivative includes dicyclopentadiene, 1,4-dihydro-1,4-methylnaphthalene or 2-phenyl-5-norbornene.

[0008] A preparation method of a COP compatibilizer, comprising the following steps: S1, 5-norbornene-2,3-dicarboxylic acid is heated to dehydrate to generate norbornene dicarboxylic anhydride at 180-220℃; S2, norbornene dicarboxylic anhydride and norbornene or its derivative are reacted for 30-90 min at 40-60℃ in the presence of a metal carbene complex catalyst to generate a norbornene copolymer through metathesis ring-opening polymerization; the residual monomer after the reaction of step S1 and step S2 is little, and the unreacted monomer will be reacted and removed together in the subsequent catalytic hydrogenation process; S3, the norbornene copolymer is catalytically hydrogenated in the presence of a palladium-carbon catalyst at 180-200℃ for 1-3 h to generate an anhydride-functionalized COP; S4, the anhydride-functionalized COP and polypropylene glycidyl ester or polyethylene glycidyl ester are reacted and extruded in an inert atmosphere at 180-220℃ to generate COP-g-PP / PE.

[0009] The reaction mechanism of the COP compatibilizer of the present application is as follows: The adjacent two carboxyl groups of norbornene dicarboxylic acid undergo nucleophilic acyl substitution reaction at high temperature to generate norbornene dicarboxylic anhydride by removing one molecule of water, and then norbornene dicarboxylic anhydride and norbornene (or its derivative) form a norbornene copolymer containing double bonds in the main chain under the action of a transition metal carbene catalyst, and then the olefin double bonds in the main chain or side chain and hydrogen gas undergo addition reaction and hydrogenation in the presence of a palladium-carbon catalyst at high temperature and high pressure to generate saturated bonds from double bonds, and the performance is more stable. The generated anhydride-functionalized COP molecular chain has a reactive anhydride group, which can react with polyolefin glycidyl ester through extrusion reaction, and the anhydride group and the glycidyl ether epoxy group generate ester bonds to obtain COP-g-PP / PE.

[0010] A multilayer co-extrusion film, comprising a COP layer, an adhesive layer and a PP layer arranged in sequence, and the material of the adhesive layer is the COP compatibilizer. The COP compatibilizer can react with the COP of the upper and lower layers through anhydride reaction and with the PP through compatibility / cocrystallization in a short time of co-extrusion, to form chemical and physical double combinations, and can give extremely high interlayer peeling strength. The COP layer in the multilayer co-extrusion film refers to non-anhydridized COP.

[0011] A multilayer co-extruded film includes, from the inside out, an inner layer, a second inner layer, a middle layer, a second outer layer, and an outer layer. The inner layer is made of COP and a COP compatibilizer in a mass ratio of 70:20-40. The second inner layer is made of the COP compatibilizer. The middle and second outer layers are made of PP and SEBS in a mass ratio of 65:30-40. The outer layer is made of PP. In this multilayer co-extruded film, the COP in the inner layer material refers to unanhydrinated COP.

[0012] When pure COP is used as an inner layer, its glass transition temperature is very high, far exceeding the melting temperature of commonly used heat-sealing materials (such as LDPE, LLDPE, and PP). This means that even when sufficient heat is applied to melt the heat-sealing layer, the COP layer remains in a glassy state and cannot participate in the melt diffusion process. Furthermore, COP's nonpolar, saturated hydrocarbon chain structure results in low surface energy, lacking strong interactions (chemical bonds or strong hydrogen bonds) with either polar or nonpolar heat-sealing materials. This leads to weak interfacial adhesion, and heat sealing relies entirely on weak physical adsorption, resulting in extremely low strength. Therefore, traditionally, COP cannot be directly used as an inner layer requiring heat-sealing functionality.

[0013] Based on this, the inventors used an anhydride-functionalized COP and a graft copolymer of polyolefin grafted glycidyl ester (COP-g-PP / PE) as the inner layer. First, through a chemical reaction, flexible PP or PE segments are covalently grafted onto the rigid anhydride-functionalized COP main chain, which is equivalent to "building" polyolefin components into the anhydride-functionalized COP. Its thermal properties will be closer to those of polyolefin. When the heat sealing knife is heated, the phase region composed of polyolefin segments in the material will melt preferentially, thereby forming a melt at a relatively low temperature, which has the basic conditions to participate in the heat sealing process. Second, the anhydride-functionalized COP segments in the inner layer material and the adjacent functional layers in the multilayer film can form strong chemical bonds and physical bonds through the same "anhydride-epoxy" reaction or molecular chain entanglement / co-solubility during co-extrusion. This ensures that there is no delamination between the inner layer and the main structural layer. The force applied during heat sealing can be effectively transmitted to the whole film through this strong interface, without peeling between the inner layer and the main layer, thus achieving high-strength heat sealing.

[0014] The technical solution of the present invention has at least the following advantages and beneficial effects: 1. Anhydride-functionalized COP and polyolefin-grafted glycidyl esters form ester bonds through the reaction of anhydride groups and epoxy groups. The bond energy of the ester bonds is much higher than that of physical interactions (van der Waals forces, hydrogen bonds), thus firmly connecting the incompatible COP phase and PP / PE phase together. When subjected to external forces, stress can be effectively transferred between the two phases through chemical bonds, preventing interfacial delamination and crack propagation, thereby significantly improving the mechanical properties of the membrane material.

[0015] 2. The reaction between anhydride-functionalized COP and polyolefin-grafted glycidyl ester occurs at the interface between the two phases. The resulting COP-g-PP / PE graft copolymer is a highly efficient "interfacial emulsifier." Its COP segments dissolve in the anhydride-functionalized COP phase, and the PP / PE segments dissolve in the PP phase, anchoring at the interface through chemical bonds, significantly reducing interfacial tension. During melt blending, it promotes a finer and more uniform dispersed phase size, and due to the chemical anchoring effect, the phase morphology is less prone to coarsening during subsequent processing or use, resulting in more stable performance.

[0016] 3. When COP-g-PP / PE graft copolymer is used as the adhesive layer in a multilayer film, this reactive copolymer can form a dual chemical and physical bond with COP through acid anhydride reaction and with PP through compatibility / co-crystallization within a short time during co-extrusion, which can impart excellent interlayer peel strength.

[0017] 4. When COP-g-PP / PE graft copolymer is used as the inner layer in a multilayer co-extruded film, the inner layer and the main structural layer are chemically bonded at the interface, which improves the heat sealing strength. At the same time, since the inner layer material contains easily molten polyolefin segments and has high interfacial chemical reactivity, it can achieve excellent heat sealing strength at relatively low temperatures and in a short time, which is beneficial to improving production speed and reducing the impact on heat-sensitive contents. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the COP compatibilizer synthesis process provided in an embodiment of the present invention.

[0019] Figure 2 This is a schematic diagram of the structure of the multilayer co-extruded film provided in Embodiment 4 of the present invention.

[0020] Figure 3 This is a schematic diagram of the structure of the multilayer co-extruded film provided in Embodiment 5 of the present invention.

[0021] Figure 4 The infrared spectrum of COP-g-PP provided in Embodiment 1 of the present invention. Detailed Implementation

[0022] The present invention will be further described below with reference to specific embodiments, but the embodiments do not limit the present invention in any way. Unless otherwise stated, the raw materials and reagents used in the embodiments of the present invention are conventionally purchased raw materials and reagents.

[0023] Example 1 A method for preparing a COP compatibilizer includes the following steps: S1 and 5-norbornene-2,3-dicarboxylic acid were placed in a dry reaction vessel, heated to 200°C, and kept at the temperature until no more water was generated to obtain norbornene dicarboxylic anhydride. S2. Norbornene dicarboxylic anhydride and norbornene in a mass ratio of 5:96.5 are reacted at 50°C for 60 min in the presence of a metal carbene complex catalyst to generate a norbornene copolymer through a metatopic ring-opening polymerization reaction. S3 and norbornene copolymer were reacted at 190°C for 2 hours in the presence of palladium on carbon catalyst to catalytic hydrogenation and generate anhydride-functionalized COP. S4. Anhydride-functionalized COP, glycidyl polypropylene (Fine-Blend: SPG-02, high grafting rate 0.5-0.8wt%), and antioxidant 1010 in a mass ratio of 35:65:0.1 are reacted and extruded at 190°C in an inert atmosphere to generate COP-grafted polypropylene (COP-g-PP).

[0024] For the synthesis process of COP-g-PP, please refer to [link / reference]. Figure 1 For the infrared spectrum of COP-g-PP, please refer to [link / reference]. Figure 4 .exist Figure 4 The data also includes the infrared spectra of polypropylene (PP) and unanhydrinated COP. As can be seen from the figure, the infrared spectrum of the COP-g-PP copolymer contains the characteristic peak of COP at 919 cm⁻¹. -1 The characteristic peak of polypropylene at 972 cm⁻¹ also exists. -1 This indicates that the reaction was completed according to the designed steps.

[0025] Example 2 A method for preparing a COP compatibilizer includes the following steps: S1 and 5-norbornene-2,3-dicarboxylic acid were placed in a dry reaction vessel, heated to 180°C, and kept at the temperature until no more water was generated to obtain norbornene dicarboxylic anhydride. S2. Norbornene dicarboxylic anhydride and dicyclopentadiene in a mass ratio of 3:92 are reacted at 60°C for 30 min in the presence of a metal carbene complex catalyst to generate a norbornene copolymer through a metathesis ring-opening polymerization reaction. S3 and norbornene copolymer were reacted at 200°C for 1 h in the presence of palladium on carbon catalyst to catalytic hydrogenation and generate anhydride-functionalized COP. S4. Anhydride-functionalized COP, glycidyl ester (Sumitomo Chemical, Japan: BF-2C, GMA content 6%), and antioxidant 1010 in a mass ratio of 30:70:0.1 are reacted and extruded at 220°C in an inert atmosphere to generate COP-grafted polyethylene (COP-g-PE).

[0026] Example 3 A method for preparing a COP compatibilizer includes the following steps: S1 and 5-norbornene-2,3-dicarboxylic acid were placed in a dry reaction vessel, heated to 220°C, and kept at that temperature until no more water was generated to obtain norbornene dicarboxylic anhydride. S2. Norbornene dicarboxylic anhydride and 2-phenyl-5-norbornene in a mass ratio of 8:97 are reacted at 40°C for 90 min in the presence of a metal carbene complex catalyst to generate a norbornene copolymer through a metathesis ring-opening polymerization reaction. S3 and norbornene copolymer were reacted at 180°C for 3 hours in the presence of palladium on carbon catalyst to catalytic hydrogenation and generate anhydride-functionalized COP. S4. Anhydride-functionalized COP, glycidyl polypropylene (Fine-Blend: SPG-02, high grafting rate 0.5-0.8wt%), and antioxidant 1010 in a mass ratio of 50:50:0.1 are reacted and extruded at 180°C in an inert atmosphere to generate COP-grafted polypropylene (COP-g-PP).

[0027] Example 4 A multilayer co-extruded film includes a COP layer, an adhesive layer, and a PP layer arranged sequentially. The adhesive layer is made of COP-g-PP prepared in Example 1. COP, COP-g-PP, and PP are respectively added to three extruders of a three-layer casting film equipment and cast to form a film, thereby obtaining a co-extruded composite film. See [link to relevant documentation]. Figure 2 The COP in the COP layer refers to the unanhydrinated COP.

[0028] Example 5 A multilayer co-extruded film includes, from the inside out, an inner layer, a second inner layer, a middle layer, a second outer layer, and an outer layer. The inner layer is made of COP and COP-g-PP prepared in Example 1 at a mass ratio of 70:20-40. The second inner layer is made of COP-g-PP prepared in Example 1. The middle and second outer layers are made of PP and SEBS at a mass ratio of 65:35. The outer layer is made of PP. The multilayer co-extruded composite film is prepared using a five-layer down-blowing water-cooling process. See [link to relevant documentation]. Figure 3 The COP in the inner layer material refers to the unanhydrinated COP.

[0029] Comparative Example 1 The difference between this comparative example and Example 4 is that COP-g-PP is not added to the adhesive layer.

[0030] Comparative Example 2 The difference between this comparative example and Example 5 is that COP-g-PP is not added to the inner layer.

[0031] Comparative Example 3 The difference between this comparative example and Example 1 is that: unanhydrinated COP, glycidyl polypropylene, and antioxidant 1010 were reacted and extruded in an inert atmosphere at 190°C to generate a graft copolymer. This graft copolymer was used as an adhesive layer or inner layer to produce a co-extruded film.

[0032] When used as an adhesive layer, the co-extruded film comprises a COP layer, a graft copolymer layer, and a PP layer arranged sequentially, and the manufacturing method is described in Example 4.

[0033] When used as an inner layer, the co-extruded film includes an inner layer, a second inner layer, a middle layer, a second outer layer, and an outer layer arranged sequentially from the inside to the outside. The inner layer is made of a cyclic olefin polymer and a graft copolymer layer in a mass ratio of 70:20-40. The second inner layer is made of a graft copolymer layer. The middle and second outer layers are made of PP and SEBS in a mass ratio of 65:35. The outer layer is made of PP. The manufacturing method is described in Example 5.

[0034] The performance comparison of the multilayer co-extruded films prepared in Example 4 with those of Comparative Examples 1 and 3 is as follows: Table 1 Tensile strength of multilayer co-extruded films

[0035] The performance of the multilayer co-extruded films prepared in Example 5 is compared with those in Comparative Examples 2 and 3 as follows: Table 2 Heat Seal Strength of Multilayer Co-extruded Films

[0036] The tensile strength test method is GB / T 1040.3 Determination of tensile properties of plastics - Part 3: Test conditions for films and sheets, and the heat seal strength test method is YBB00122003-2015 Method 1.

[0037] According to the performance comparison in Tables 1 and 2, the multilayer co-extruded film with added COP-g-PP exhibits higher tensile strength and heat-sealing strength. This indicates that the COP-g-PP graft copolymer provided by this invention has good compatibility with PP / PE, can improve the mechanical properties of the film material, and can also improve the heat-sealing performance of the multilayer co-extruded film.

[0038] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A COP compatibilizer, characterized in that, The COP compatibilizer is a graft copolymer of anhydride-functionalized COP and polyolefin-grafted glycidyl ester; wherein the COP segment accounts for 30-50%, and the polyolefin-grafted glycidyl ester includes polypropylene glycidyl ester or polyethylene glycidyl ester.

2. The COP compatibilizer according to claim 1, characterized in that, The anhydride-functionalized COP is obtained by polymerizing dehydrated 5-norbornene-2,3-dicarboxylic acid with norbornene or a norbornene derivative followed by catalytic hydrogenation.

3. The COP compatibilizer according to claim 2, characterized in that, The norbornene derivatives include dicyclopentadiene, 1,4-dihydro-1,4-methylnaphthalene, or 2-phenyl-5-norbornene.

4. The COP compatibilizer according to claim 2, characterized in that, The mass ratio of 5-norbornene-2,3-dicarboxylic acid to norbornene or norbornene derivatives is 3-8:92-97.

5. The COP compatibilizer according to claim 1, characterized in that, The mass ratio of the anhydride-functionalized COP to the polyolefin-grafted glycidyl ester is 3-5:5-7.

6. The method for preparing the COP compatibilizer according to any one of claims 1-5, characterized in that, Includes the following steps: S1,5-norbornene-2,3-dicarboxylic acid is heated and dehydrated to produce norbornene dicarboxylic anhydride; S2, norbornene dicarboxylic anhydride, and norbornene or its derivatives are converted into norbornene copolymers via a metastatic ring-opening polymerization reaction. S3, norbornene copolymer is converted into anhydride-functionalized COP via catalytic hydrogenation reaction; S4. Anhydride-functionalized COP reacts with glycidyl polypropylene or glycidyl polyethylene through an extrusion reaction to generate COP-g-PP / PE.

7. The method for preparing the COP compatibilizer according to claim 6, characterized in that, The catalysts for the metatopic ring-opening polymerization reaction are metal carbene complex catalysts, and the catalysts for the catalytic hydrogenation reaction are palladium on carbon catalysts.

8. The method for preparing the COP compatibilizer according to claim 6, characterized in that, In S4, reaction extrusion is performed in an inert atmosphere at 180-220°C.

9. A multilayer co-extruded film, characterized in that, It comprises a cyclic olefin polymer layer, an adhesive layer, and a PP layer arranged sequentially, wherein the adhesive layer is made of the COP compatibilizer as described in any one of claims 1-5.

10. A multilayer co-extruded film, characterized in that, The material comprises, from the inside out, an inner layer, a sub-inner layer, a middle layer, a sub-outer layer, and an outer layer. The inner layer is made of a cyclic olefin polymer in a mass ratio of 70:20-40 and a COP compatibilizer as described in any one of claims 1-5. The sub-inner layer is made of a COP compatibilizer as described in any one of claims 1-5. The middle and sub-outer layers are made of PP and SEBS in a mass ratio of 65:30-40. The outer layer is made of PP.

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