Modified polyolefin resin, method for producing the same, and use thereof

Abstract

The application discloses a modified polyolefin resin and a preparation method and application thereof, and the modified polyolefin resin is prepared from the following components according to mass percentages: 90-98% of polyolefin, 1-10% of an epoxy compound and less than 1% of a catalyst; wherein the polyolefin is maleic anhydride grafted polyolefin or maleic anhydride copolymerized polyolefin. The application provides a brand-new polyolefin resin and a modification method thereof, and the combination strength of the resin and metal is greatly improved.

Description

Technical Field

[0001] This invention relates to the field of polyolefin resin modification, specifically a modified polyolefin resin, its preparation method, and its application. Background Technology

[0002] Thermoplastic plastics, especially high-hardness engineering plastics, often present challenges in bonding with metals. Firstly, the surface energies of plastics and metals differ significantly. General-purpose plastics, particularly polyolefins, contain virtually no polar groups, resulting in very weak adhesion to metals. Other polar plastics, such as nylon and polyester, exhibit significantly different bonding strengths compared to conventional coatings. Secondly, engineering plastics are hard and prone to crystallization, leading to higher stress at the metal interface and making them more susceptible to detachment during tearing.

[0003] Common methods to improve the bonding strength between thermoplastics and metals include: First, applying a series of surface treatments to the metal end, such as applying primers or surface treatment agents, to bring the surface energy of the metal and plastic closer, or even form stronger covalent bonds. However, this metal-end treatment is costly. Second, copolymerizing the plastic to incorporate polar monomers, such as maleic anhydride or vinyl acetate, or grafting maleic anhydride or glycidyl ethers onto the side groups of the plastic using free radical grafting, thereby increasing the polarity of the plastic itself. These modified polyolefin resins are then added to ordinary resins to improve the adhesion to metals. Currently, the second method is still largely under development and requires further refinement. Summary of the Invention

[0004] In view of this, the present invention provides a modified polyolefin resin, its preparation method and application, to solve the problems mentioned in the background art, and to provide a novel polyolefin resin and its modification method, which significantly improves the bonding strength between the resin and the metal.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] In a first aspect, the present invention discloses a modified polyolefin resin, which is prepared from the following components in the following mass percentages:

[0007] Polyolefins 90-98%,

[0008] Epoxy compounds 1-10%,

[0009] Catalyst content less than 1%;

[0010] The polyolefin is maleic anhydride-grafted polyolefin or maleic anhydride copolymer polyolefin.

[0011] As a further aspect of the present invention: the main chain of the maleic anhydride-grafted polyolefin is a homopolymer or copolymer of any one of ethylene, propylene, 1-butene, butadiene, 1-hexene, 1-octene, and styrene, and the maleic anhydride is grafted onto the polymer molecular chain.

[0012] As a further aspect of the present invention: the maleic anhydride copolymer polyolefin is obtained by copolymerizing maleic anhydride with ethylene or styrene.

[0013] As a further aspect of the present invention, the melt index of the maleic anhydride-grafted polyolefin is 200-1000 g / 10 min.

[0014] As a further aspect of the present invention: the maleic anhydride content in the maleic anhydride copolymer polyolefin is >50%.

[0015] As a further aspect of the present invention: the epoxy compound is at least one selected from epoxy resin, a mixture of various compounds having 1-2 epoxy groups; and / or,

[0016] The epoxy equivalent (EEW) of the epoxy compound is between 500 and 3000 g / mol.

[0017] As a further aspect of the present invention, the catalyst is a nitrogen-containing compound with a proton acceptor.

[0018] Secondly, the present invention discloses a method for preparing the modified polyolefin resin as described above, wherein each component is weighed according to mass percentage, mixed uniformly at 150-300°C and reacted and extruded to obtain the modified polyolefin resin.

[0019] Thirdly, the present invention discloses an application of the modified polyolefin resin as described above, wherein the modified polyolefin resin is added to a matrix resin and mixed evenly to form a new modified resin; wherein the amount of the modified polyolefin resin in the modified resin is 1-30w.

[0020] As a further aspect of the present invention, the matrix resin is polypropylene or polyamide.

[0021] Compared with the prior art, the beneficial effects of the present invention are:

[0022] This invention utilizes a co-extrusion process involving polyolefins, epoxy compounds, and a catalyst, initiating a chemical reaction on-site during extrusion. Specifically, the process involves a highly efficient ring-opening reaction between epoxy groups and maleic anhydride under the catalysis of a catalyst. Subsequently, the chemically modified maleic anhydride-grafted polypropylene / maleic anhydride copolymer is melt-blended with a matrix resin. Crucially, because the epoxy groups are fully involved in the reaction with maleic anhydride during extrusion, unintended localized cross-linking between the epoxy groups and the matrix resin that could occur during subsequent melt blending is avoided. This improvement not only ensures a smooth, flawless surface for the engineering plastic, significantly improving its appearance quality, but also enhances metal adhesion, thereby giving the material superior performance. Detailed Implementation

[0023] To facilitate understanding of the present invention, a more comprehensive description will be given below with reference to specific embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of the present invention.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0025] The specific information of the raw materials used in the following examples and comparative examples is as follows:

[0026] Resin 1: Maleic anhydride-grafted polypropylene, OREVAC CA100, SK Korea, maleic anhydride content >2%.

[0027] Resin 2; Ethylene-maleic anhydride copolymer, ZeMac E60, Vantrus, maleic anhydride content 78%.

[0028] Epoxy compound 1: Epoxy resin E06, Baling Petrochemical, epoxy equivalent 1500-1800;

[0029] Epoxy compound 2: alkyl glycidyl ether, Jiangsu Maoyun, epoxy equivalent 235;

[0030] Catalyst: Imidazole, a Chinese medicine;

[0031] Matrix resin 1: Polypropylene K4818, MI=23, Yanshan Petrochemical.

[0032] Matrix resin 2: PA1012 nylon, MI=5, Huitong New Materials.

[0033] All materials are commercially available, commonly used products.

[0034] It is understood that the above-mentioned raw materials and reagents are merely examples of some specific embodiments of the present invention, making the technical solution of the present invention clearer, and do not mean that the present invention can only use the above-mentioned reagents. The specific scope shall be determined by the claims. In addition, unless otherwise specified, "parts" in the examples and comparative examples refer to parts by weight.

[0035] Any range described in this invention includes the endpoint, any value between the endpoints, and any subrange consisting of the endpoint or any value between the endpoints.

[0036] The standards upon which the test items involved in the examples and comparative examples are based are as follows:

[0037] Melt flow index: Standard reference GB / T 3682.1-2018, test conditions: 230℃, 2.16kg;

[0038] Adhesion: A 1cm wide Q235 steel sheet was sandblasted with 200-mesh quartz sand, then ultrasonically treated with a detergent solution for 10 minutes. Finally, the sandblasted surface was wiped with acetone. The particles were then spread onto the steel sheet surface and melted onto the steel sheet surface using a flat vulcanizing machine at approximately 220℃, resulting in a resin layer thickness of 0.5-2mm. After removing the flat vulcanizing machine and allowing it to cool and solidify naturally, all the resin on the sides of the steel sheet was removed, leaving only the resin on the surface of the steel sheet. The resin layer was then peeled off from the long end of the steel sheet with a blade, pulling it apart by about 5cm, keeping the plastic layer intact and without any gaps at the edges. The pulled-out plastic layer and the peeled steel sheet were then clamped separately in the two jaws of a stretching machine, and the coating was pulled apart at a speed of 5mm / min. The maximum value during the pulling process was recorded.

[0039] Surface smoothness: Extrude sheets using a single-screw extruder at 180-220℃ and visually inspect the surface for smoothness, bumps, or overall flatness issues. Use a scale of 1-10 to indicate visually assessed flatness, with higher values ​​indicating better flatness.

[0040] Example 1

[0041] (1) Weigh 980g of polyolefin 1, 18g of epoxy compound 1, and 2g of catalyst, mix them evenly, and then extrude them in a twin-screw extruder to obtain modified polyolefin resin.

[0042] (2) The modified polyolefin resin obtained in step (1) is mixed with the matrix resin 1 at a mass ratio of 1:9 and then melt-blended in a twin-screw extruder to obtain engineering plastic 1.

[0043] The performance of engineering plastic 1 was tested, and the melt flow index MI was 32 g / 10 min, the adhesion was 12 N, and the surface smoothness was 3.

[0044] In step (1), the operating parameters of the twin-screw extruder are: zone 1 temperature 120℃, zone 2 temperature 190℃, the temperature of the remaining zones 230℃, the die head temperature 220℃, and the average residence time of the mixture is 2min; in step (2), the operating parameters of the twin-screw extruder are: zone 1 temperature 160℃, zone 2 temperature 190℃, the temperature of the remaining zones 230℃, and the die head temperature 220℃.

[0045] Example 2

[0046] (1) Weigh 950g of polyolefin 1, 45g of epoxy compound 2, and 5g of catalyst, mix them evenly, and then extrude them in a twin-screw extruder to obtain modified polyolefin resin.

[0047] (2) The modified polyolefin resin obtained in step (1) is mixed with the matrix resin 1 at a mass ratio of 1:9 and then melt-blended in a twin-screw extruder to obtain engineering plastic 2.

[0048] The performance of engineering plastic 2 was tested, and the melt flow index MI was 34 g / 10 min, the adhesion was 20 N, and the surface smoothness was 3.

[0049] In step (1), the operating parameters of the twin-screw extruder are: zone 1 temperature 120℃, zone 2 temperature 190℃, the temperature of the remaining zones 230℃, the die head temperature 220℃, and the average residence time of the mixture is 3min; in step (2), the operating parameters of the twin-screw extruder are: zone 1 temperature 160℃, zone 2 temperature 190℃, the temperature of the remaining zones 230℃, and the die head temperature 220℃.

[0050] Example 3

[0051] (1) Weigh 950g of polyolefin 1, 10g of epoxy compound 1, 30g of epoxy compound 2, and 3g of catalyst, mix them evenly, and then extrude them in a twin-screw extruder to obtain modified polyolefin resin.

[0052] (2) The modified polyolefin resin obtained in step (1) is mixed with the matrix resin 1 at a mass ratio of 3:7 and then melt-blended in a twin-screw extruder to obtain engineering plastic 3.

[0053] The performance of engineering plastic 3 was tested, and the melt flow index MI was 58 g / 10 min, the adhesion was 28 N, and the surface smoothness was 3.

[0054] In step (1), the operating parameters of the twin-screw extruder are: zone 1 temperature 120℃, zone 2 temperature 190℃, the temperature of the remaining zones 230℃, the die head temperature 220℃, and the average residence time of the mixture is 3min; in step (2), the operating parameters of the twin-screw extruder are: zone 1 temperature 160℃, zone 2 temperature 190℃, the temperature of the remaining zones 230℃, and the die head temperature 220℃.

[0055] Example 4

[0056] (1) Weigh 980g of polyolefin 1, 18g of epoxy compound 1, and 2g of catalyst, mix them evenly, and then extrude them in a twin-screw extruder to obtain modified polyolefin resin.

[0057] (2) The modified polyolefin resin obtained in step (1) is mixed with the matrix resin 2 at a mass ratio of 5:95 and then melt-blended in a twin-screw extruder to obtain engineering plastic 4.

[0058] The performance of engineering plastic 4 was tested, and the melt flow index MI was 3 g / 10 min, the adhesion was 25 N, and the surface smoothness was 3.

[0059] In step (1), the operating parameters of the twin-screw extruder are: zone 1 temperature 120℃, zone 2 temperature 190℃, the temperature of the remaining zones 230℃, the die head temperature 220℃, and the average residence time of the mixture is 4min; in step (2), the operating parameters of the twin-screw extruder are: zone 1 temperature 160℃, zone 2 temperature 190℃, the temperature of the remaining zones 230℃, and the die head temperature 220℃.

[0060] Example 5

[0061] (1) Weigh 980g of polyolefin 1, 18g of epoxy compound 1, and 2g of catalyst, mix them evenly, and then extrude them in a twin-screw extruder to obtain modified polyolefin resin.

[0062] (2) The modified polyolefin resin obtained in step (1) is mixed with the matrix resin 2 at a mass ratio of 2:98 and then melt-blended in a twin-screw extruder to obtain engineering plastic 5.

[0063] Performance tests were conducted on engineering plastic 5, and the melt flow index MI was measured to be 0.5 g / 10 min, adhesion was >30 N, and surface smoothness was 4.

[0064] In step (1), the operating parameters of the twin-screw extruder are: zone 1 temperature 120℃, zone 2 temperature 190℃, the temperature of the remaining zones 230℃, the die head temperature 220℃, and the average residence time of the mixture is 4min; in step (2), the operating parameters of the twin-screw extruder are: zone 1 temperature 160℃, zone 2 temperature 190℃, the temperature of the remaining zones 230℃, and the die head temperature 220℃.

[0065] Comparative Example 1

[0066] Polyolefin 1 and matrix resin 1 were mixed evenly at a mass ratio of 1:9 and then added to a twin-screw extruder for melt blending. The melt blending process parameters of the twin-screw extruder were the same as in Example 1 to obtain engineering plastic 6. The melt index MI of engineering plastic 6 was measured to be 36 g / 10 min, the adhesion was 6 N, and the surface smoothness was 3.

[0067] Comparative Example 2

[0068] Weigh 950g of polyolefin 1, 45g of epoxy compound 2, 5g of catalyst, and 9kg of matrix resin 1. After mixing evenly, directly melt-blend through a twin-screw extruder. The melt blending process parameters are the same as in Example 2 to obtain engineering plastic 7. The melt index MI of engineering plastic 7 was measured to be 37g / 10min, the adhesion was 12N, and the surface smoothness was 3.

[0069] Comparative Example 3

[0070] Weigh 950g of polyolefin 1, 10g of epoxy compound 1, 30g of epoxy compound 2, and 9kg of matrix resin 1. Mix them evenly and then melt-blend them through a twin-screw extruder. The melt blending process conditions are the same as in Example 3 to obtain engineering plastic 8. The melt index MI of engineering plastic 8 is measured to be 70g / 10min, the adhesion is 25N, and the surface roughness and smoothness are 5.

[0071] Comparative Example 4

[0072] Weigh 500g of polyolefin 1 and 9.5kg of matrix resin 2 and mix them evenly. Then, melt blend them through a twin-screw extruder under the same melt blending conditions as in Example 4 to obtain engineering plastic 9. The melt index MI of engineering plastic 9 was measured to be 8g / 10min, the adhesion was 17N, and the surface smoothness was 6.

[0073] Comparative Example 5

[0074] Weigh 490g of polyolefin 1, 9g of epoxy compound 1, 1g of catalyst, and 9.5kg of matrix resin 2 and mix them evenly. Then, melt blend them through a twin-screw extruder under the same melt blending conditions as in Example 4 to obtain engineering plastic 10. The melt index MI of engineering plastic 10 was measured to be 1.5g / 10min, the adhesion was 20N, and the surface smoothness was 6.

[0075] Comparative Example 6

[0076] Weigh 178g of polyolefin 2, 20g of epoxy compound 1, 2g of catalyst, and 9.8kg of matrix resin 2 and mix them evenly. Then, melt-blend the mixture through a twin-screw extruder under the same melt-blending conditions as in Example 5 to obtain engineering plastic 11. The melt index MI of engineering plastic 11 was measured to be 0.2g / 10min, the adhesion was 25N, and the surface smoothness was 8.

[0077] As can be seen from the comparison between Example 1 and Comparative Example 1, by adding the same amount of the modified polyolefin described in this invention, the adhesion of the polypropylene substrate to the metal is significantly improved compared with that of maleic anhydride-grafted polypropylene, while the appearance remains unchanged.

[0078] Comparing Example 2 with Comparative Example 2, it can be seen that by first reacting maleic anhydride-grafted polypropylene with an epoxy compound and then adding it to the polypropylene matrix, the reaction between the epoxy and maleic anhydride can be more complete; while adding the matrix resin into the reaction greatly reduces the possibility of reaction, thus reducing the bonding effect.

[0079] Comparing Example 3 and Comparative Example 3, it can be seen that when the proportion of modified polyolefin resin added is relatively large, no appearance problems were found when maleic anhydride-grafted polypropylene reacts with the epoxy compound first and then is added to the polypropylene substrate. However, the product that is directly mixed shows that the epoxy compound separates from the resin phase, resulting in a rough surface.

[0080] Comparing Example 4 with Comparative Example 4, it can be seen that when modified polyolefin resin is added to nylon resin (matrix resin 2), if maleic anhydride-grafted polypropylene reacts with the epoxy compound first and then is added, it has better bonding strength than adding maleic anhydride-grafted polypropylene alone.

[0081] Comparing Example 4 and Comparative Example 5, it can be seen that since the nylon resin (matrix resin 2) reacts with the epoxy during extrusion, direct extrusion with the epoxy compound and nylon will result in local cross-linking of the nylon, leading to roughness during extrusion. However, when maleic anhydride-grafted polypropylene is added to nylon after reacting with the epoxy compound, the epoxy groups have already reacted completely, so it does not affect the appearance during extrusion, and the bonding strength is also better.

[0082] Comparing Example 5 and Comparative Example 6, it can be seen that adding polyethylene copolymer maleic anhydride to the matrix resin after reaction with an epoxy compound results in better appearance and bonding strength than directly blending it with the matrix resin.

[0083] Although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

[0084] Therefore, the above description is only a preferred embodiment of this application and is not intended to limit the scope of this application; that is, all equivalent modifications made in accordance with the scope of the claims of this application shall be within the protection scope of the claims of this application.

Claims

1. An application of a modified polyolefin resin, characterized in that, The modified polyolefin resin is added to the matrix resin at a ratio of 1-30 wt% to form a modified resin, which is used to improve the adhesion strength between the matrix resin and the metal. The modified polyolefin resin is prepared from the following components in the following mass percentages: Polyolefins 90-98%, Epoxy compounds 1-10%, Catalyst less than 1%; Wherein, the polyolefin is maleic anhydride-grafted polyolefin or maleic anhydride copolymer polyolefin. The modified polyolefin resin is prepared by weighing each component by mass percentage, mixing them evenly at 150-300℃ and reacting and extruding to obtain the modified polyolefin resin.

2. The application of the modified polyolefin resin according to claim 1, characterized in that, The main chain of the maleic anhydride-grafted polyolefin is a homopolymer or copolymer of any one of ethylene, propylene, 1-butene, butadiene, 1-hexene, 1-octene, and styrene, with the maleic anhydride grafted onto the polymer molecular chain.

3. The application of the modified polyolefin resin according to claim 1, characterized in that, The maleic anhydride copolymer polyolefin is obtained by copolymerizing maleic anhydride with ethylene or styrene.

4. The application of the modified polyolefin resin according to claim 1 or 3, characterized in that, The maleic anhydride content in the maleic anhydride copolymer polyolefin is >50%.

5. The application of the modified polyolefin resin according to claim 1, characterized in that, The epoxy compound is at least one of epoxy resin, compound with 1-2 epoxy groups; and / or, The epoxy equivalent (EEW) of the epoxy compound is between 500 and 3000 g / mol.

6. The application of the modified polyolefin resin according to claim 1, characterized in that, The catalyst is a nitrogen-containing compound with a proton acceptor.

7. The application of the modified polyolefin resin according to claim 1, characterized in that, The matrix resin is a polyolefin or a polyamide.