Polypropylene composition as well as preparation method and application thereof

Abstract

The invention discloses a polypropylene composition as well as a preparation method and application thereof, and relates to the technical field of macromolecules. The polypropylene composition comprises the following components in parts by weight: 48-66 parts of polypropylene resin; 7 to 14 parts of polycarbonate; 1-7 parts of a compatilizer; and 2-12 parts of tackifying resin. According to the invention, the problem of poor compatibility of polypropylene and polycarbonate in the blending process is solved, so that the polypropylene composition has excellent mechanical properties and heat-resistant stability at the same time.

Description

Technical Field

[0001] The present invention relates to the technical field of polymers, and in particular to a polypropylene composition and a preparation method and application thereof. Background Art

[0002] Polypropylene (PP), as a thermoplastic, is widely used in many fields due to its advantages such as light weight, high strength, wear resistance, chemical resistance and thermal stability. Polycarbonate (PC) is known for its high transparency, heat resistance, flame retardancy, impact resistance and chemical corrosion resistance, and is a leader among high-performance materials. Blending PP and PC aims to combine the advantages of both and create a composite material with higher comprehensive performance. This blended material not only inherits the high strength and wear resistance of PP, but also retains the high transparency and excellent impact resistance of PC, while improving the heat resistance and chemical stability to a certain extent.

[0003] However, there are significant differences between PP and PC in polarity and molecular structure, which becomes a major challenge in the blending process of the two. PP is a non-polar polymer, and its molecular chain is mainly composed of non-polar propylene units; while PC is a polar polymer, and its molecular chain contains polar groups. This difference makes it difficult for the two to form a uniform phase structure when mixed, and the compatibility is poor. After blending, it is easy to form a multiphase morphological structure. This structure not only affects the mechanical properties of the material, such as strength and toughness, but may also cause phase separation of the material under long-term use or environmental changes, thereby reducing the stability and service life of the material. Summary of the invention

[0004] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a polypropylene composition and a preparation method and application thereof. The present invention solves the problem of poor compatibility between polypropylene and polycarbonate during the blending process, so that the polypropylene composition has excellent mechanical properties and heat resistance stability.

[0005] To achieve the above object, the technical solution adopted by the present invention is:

[0006] In a first aspect, the present invention provides a polypropylene composition comprising the following components in parts by weight:

[0007] 48-66 parts of polypropylene resin; 7-14 parts of polycarbonate; 1-7 parts of compatibilizer; 2-12 parts of tackifying resin.

[0008] The present invention takes polypropylene resin as the main body, adds polycarbonate to integrate its high-performance characteristics, and adds a compatibilizer with certain polar groups and interfacial wetting and bridging effects, which can alleviate the polarity mismatch problem between PP and PC to a certain extent. As a class of small molecule compounds that can significantly improve the viscosity of rubber materials, the molecular structure microscopic characteristics of tackifying resins have a profound impact on performance and application. Utilizing the molecular structure microscopic characteristics of tackifying resins, it can not only effectively insert between the molecular chains of PP and PC, but also effectively insert between the molecular chains of compatibilizers, so that the overall formation of a stable interaction force, but also through its unique viscoelastic behavior, in the blending process of PP and PC, promote the uniform dispersion and fusion of the two phases, and effectively inhibit the formation of a multiphase morphological structure. Therefore, the present invention adopts the synergistic effect of tackifying resins and compatibilizers, innovatively solves the compatibility problem when PP is blended with a relatively small amount of PC, realizes efficient fusion and stable coexistence between the two phases, and significantly improves the mechanical properties and long-term use stability of PP / PC blends.

[0009] Preferably, the tackifying resin is a terpene resin.

[0010] The present invention uses terpene resin as a tackifying resin, so that the impact strength of the polypropylene composition under low temperature conditions can be significantly improved. This is because the terpene resin can maintain a certain degree of flexibility and elasticity at low temperatures, thereby absorbing and dispersing impact energy and reducing material damage.

[0011] Preferably, the softening point of the terpene resin is 85-110°C, more preferably 85-100°C.

[0012] The present invention adopts a tackifying resin with a softening point of 85-100° C., which can provide sufficient hardness and stability while maintaining good processing performance, thereby achieving a balance between performances.

[0013] More preferably, the softening point of the terpene resin is in the range of any one or both of 85°C, 86°C, 87°C, 88°C, 89°C, 90°C, 92°C, 94°C, 95°C, 98°C, 99°C and 100°C.

[0014] Preferably, the mass ratio of the terpene resin to the polycarbonate is (0.5-1):1.

[0015] The present invention adopts a specific ratio of terpene resin and polycarbonate to compound, which is conducive to promoting the good dispersion and interaction of terpene resin and polycarbonate in the polypropylene matrix. On the basis of maintaining the excellent performance of polycarbonate, the comprehensive performance of the material can be further improved to achieve a balance between the performances.

[0016] Preferably, the molecular weight of the tackifying resin is 300-10000.

[0017] Preferably, the polypropylene resin includes homopolymer polypropylene resin and copolymer polypropylene resin.

[0018] Preferably, after the polycarbonate is dried, its moisture content is less than 0.15 wt %.

[0019] Preferably, the surface of the tackifying resin is pretreated with a silane coupling agent.

[0020] As an organic-inorganic bridging agent, silane coupling agent contains two different types of functional groups in its molecular structure. One end can react chemically with inorganic substances (such as hydroxyl and carboxyl groups on the surface of tackifying resin), and the other end can produce good compatibility with organic substances (such as polypropylene matrix). Therefore, pre-treating the surface of tackifying resin with silane coupling agent can significantly enhance the interfacial compatibility and adhesion between tackifying resin and polypropylene matrix.

[0021] The silane coupling agent pre-treated tackifying resin surface can be commercially available or homemade. The homemade method is a common method in the art. For example, the tackifying resin can be pre-treated by direct addition. The specific method is: add the crushed tackifying resin to an excess of silane coupling agent, and stir it to fully and evenly disperse it in the silane coupling agent to obtain a mixed solution. Then, the mixed solution is heated to evaporate the silane coupling agent to separate it, and the treated tackifying resin is obtained. The weight ratio of the tackifying resin to the silane coupling agent is 1: (5-10).

[0022] Preferably, the silane coupling agent includes at least one of silane coupling agents KH560 and KH590.

[0023] Preferably, the compatibilizer includes at least one of polyethylene grafted maleic anhydride and polypropylene grafted maleic anhydride.

[0024] Further preferably, the compatibilizer comprises polyethylene grafted maleic anhydride and polypropylene grafted maleic anhydride, and the mass ratio of the polyethylene grafted maleic anhydride to the polypropylene grafted maleic anhydride is 1:(0.5-2), preferably 1:(1-1.5).

[0025] Preferably, the mass percentage of the polypropylene resin in the polypropylene composition is not less than 50%.

[0026] Preferably, the polypropylene composition comprises the following components in parts by weight:

[0027] Polypropylene 50-65 parts; polycarbonate 8-12 parts; compatibilizer 2-6 parts; tackifying resin 3-10 parts.

[0028] Further preferably, the polypropylene composition comprises the following components in parts by weight:

[0029] Polypropylene 60-65 parts; polycarbonate 10-12 parts; compatibilizer 3-5 parts; tackifying resin 5-8 parts.

[0030] Preferably, the polypropylene composition further comprises 0-10 parts of filler and 0-6 parts of auxiliary agent.

[0031] The invention further improves the processing performance and mechanical properties of the polypropylene composition material by adding fillers and additives in appropriate amounts, thereby ensuring the stability of the blended material during the preparation process and the high quality of the finished product.

[0032] More preferably, the polypropylene composition further comprises 5-8 parts of filler and 1-4 parts of auxiliary agent.

[0033] Preferably, the filler includes at least one of calcium carbonate and glass fiber.

[0034] Preferably, the auxiliary agent includes a lubricant and a nucleating agent.

[0035] Preferably, the lubricant includes at least one of calcium stearate and zinc stearate.

[0036] Preferably, the nucleating agent is a β-crystal nucleating agent.

[0037] In a second aspect, the present invention further provides a method for preparing a polypropylene composition, comprising the following steps:

[0038] After the components are uniformly mixed, they are added into a twin-screw extruder, melt-kneaded, extruded and granulated to obtain a polypropylene composition.

[0039] In a third aspect, the present invention also provides an application of the polypropylene composition in automobile accessories.

[0040] The polypropylene composition of the present invention has excellent mechanical properties and heat resistance stability and is suitable for automobile accessories.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] (1) The technical solution of the polypropylene composition of the present invention significantly improves the comprehensive performance of the polypropylene composition material through the addition of a tackifying resin and its synergistic effect with a compatibilizer, showing a synergistic beneficial effect. First, as a key component, the tackifying resin can effectively improve the interfacial compatibility between polypropylene and polycarbonate, and promote the uniform dispersion and close combination of the two polymer phases by enhancing the intermolecular interaction force, thereby significantly improving the overall adhesion and cohesive strength of the mixture. This tackifying effect not only optimizes the processing properties of the material, such as improving the melt fluidity in the molding process such as extrusion and injection molding, but also reduces the performance degradation problem caused by phase separation, ensuring the stability and consistency of product quality.

[0043] (2) The compatibilizer of the present invention plays a vital role in the system. It not only has good interfacial activity and can further reduce the interfacial tension between polypropylene and polycarbonate, but also promotes the interaction between the tackifying resin and the matrix resin to form a more stable phase structure. This multi-level compatibility optimization not only enhances the mechanical strength of the material, but also improves its long-term performance such as heat resistance and weather resistance.

[0044] (3) The present invention provides additional physical reinforcement effects for the material and reduces the production cost of the product while controlling the cost by adding an appropriate amount of filler, and the appropriate use of processing aids further optimizes the processing process, reduces energy consumption, and improves production efficiency. DETAILED DESCRIPTION

[0045] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments, but the protection scope and implementation methods of the present invention are not limited thereto.

[0046] Unless otherwise specified, the materials and reagents used in the following examples are commercially available.

[0047] Embodiments 1-11, 13

[0048] The embodiments of the polypropylene composition and the preparation method thereof of the present invention, the components of the polypropylene composition are shown in Table 1.

[0049] The method for preparing the polypropylene composition comprises the following steps:

[0050] (1) uniformly mixing polypropylene, polycarbonate and a compatibilizer to obtain a first premix;

[0051] (2) adding the filler to the first premix and mixing evenly to obtain a second premix;

[0052] (3) adding the tackifying resin and the processing aid to the second premix and mixing them evenly, controlling the stirring speed at 100 rpm for 30 seconds, to obtain a third premix, wherein the tackifying resin is fully crushed before use to avoid the formation of large particles;

[0053] (4) The third premix is ​​added to the main feed port of the extruder, and the polypropylene composition is obtained through melt blending, extrusion granulation and drying, wherein the extrusion temperature of the twin-screw extruder is 220°C to 240°C, the first section is 220°C, the second to fourth sections are 240°C, the fifth to eighth sections are 230°C, and the ninth section of the die head is 220°C to obtain the polypropylene composition.

[0054] Example 12

[0055] A polypropylene composition, wherein each step in the preparation method thereof and the reagents and process parameters used in each step are the same as those in Example 1, except that the surface of the tackifier resin is pretreated with a silane coupling agent. The specific steps are as follows: Add the crushed tackifier resin to an excess of silane coupling agent KH560, and disperse it fully and evenly in the silane coupling agent by stirring. The purpose of this step is to allow the molecules or particles of the tackifier resin to fully contact the solvent, laying the foundation for subsequent surface modification or functionalization. At 40°C, stirring speed of 30rpm, stirring time of 3min, the tackifier resin and the silane coupling agent are fully reacted. The treated solution is heated to evaporate the silane coupling agent and separated to obtain the treated tackifier resin. Cool, and re-crush the partially agglomerated tackifier resin for subsequent process steps.

[0056] Comparative Examples 1-4

[0057] The difference between each comparative example and the embodiment is only in the type and proportion of components, as shown in Table 2.

[0058] Among the components described in each embodiment and comparative example:

[0059] The polypropylene resin 1 is a homopolymer polypropylene resin, manufactured by China Science and Technology Refining and Chemical Industry, with a model of PPH-T03 and a melt index of 3.0 g / 10 min;

[0060] The polypropylene resin 2 is a copolymer polypropylene resin, manufactured by Lotte Chemical, with a model number of K8003 and a melt index of 3.5 g / 10 min.

[0061] The polycarbonate 1 is manufactured by Wanhua and its model is A1225;

[0062] The polycarbonate 2 is manufactured by LG Chemical and has a model number of 1201-22;

[0063] The compatibilizer 1 is polyethylene grafted maleic anhydride;

[0064] The compatibilizer 2 is polypropylene grafted with maleic anhydride;

[0065] The compatibilizer 3 is polyethylene grafted maleic anhydride and polypropylene grafted maleic anhydride, and the mass ratio of the two is 1:1;

[0066] The compatibilizer 4 is polyethylene grafted maleic anhydride and polypropylene grafted maleic anhydride, and the mass ratio of the two is 1:1.5;

[0067] The compatibilizer 5 is polyethylene grafted maleic anhydride and polypropylene grafted maleic anhydride, and the mass ratio of the two is 1:2;

[0068] The compatibilizer 6 is polyethylene grafted maleic anhydride and polypropylene grafted maleic anhydride, and the mass ratio of the two is 1:0.5;

[0069] The manufacturer of the polyethylene grafted with maleic anhydride is Jiayirong, model number is CMG5804, and the manufacturer of the polypropylene grafted with maleic anhydride is Nanhai Bochen, model number is PC-3.

[0070] The tackifying resin 1 is a terpene resin, model TM85, softening point 85°C, and manufactured by Guangdong Nuochi;

[0071] The tackifying resin 2 is a terpene resin, model TM100, softening point 100°C, and the manufacturer is Guangdong Nuochi;

[0072] The tackifying resin 3 is a terpene resin pretreated with a silane coupling agent, the model of the terpene resin is TM85, the softening point is 85° C., and the manufacturer is Guangdong Nuochi;

[0073] The tackifying resin 4 is a terpene resin, model TM110, softening point 110°C, manufactured by Guangdong Nuochi;

[0074] The particle size of the calcium carbonate is 1250 mesh, and the manufacturer is Rongzheng Chemical.

[0075] The nucleating agent is a β-crystal nucleating agent, the model is NP-328, and the manufacturer is Ji Haichuan.

[0076] The lubricant is zinc stearate, and the manufacturer is Huijinchuan Chemical.

[0077] Unless otherwise specified, the components and raw materials used in the embodiments and comparative examples of the present invention are all commercially available raw materials, and the components and raw materials used in each parallel experiment are all of the same kind.

[0078] Table 1

[0079]

[0080]

[0081] Table 2

[0082]

[0083]

[0084] In order to verify the performance of the polypropylene composition of the present invention, the polypropylene composition prepared in each example and comparative example was injection molded into a specimen to test the following properties.

[0085] Performance testing method:

[0086] (1) Tensile strength: tested in accordance with ISO 527-2-2016 standard, with a tensile speed of 50 mm / min;

[0087] (2) Izod notched impact strength: tested in accordance with ISO 180-2000;

[0088] (3) Surface condition of injection molded parts: Color plates were injection molded using the prepared polypropylene composition material, and the surface uniformity was observed.

[0089] (4) Heat resistance stability: Make a color plate, put it into a constant temperature furnace at 150 degrees, place a 500g weight on the color plate, and take it out after 2 hours to observe the dents on the color plate.

[0090] The performance parameters obtained from the above tests are shown in Tables 3 and 4.

[0091] Table 3

[0092]

[0093]

[0094] Table 4

[0095]

[0096] According to Table 3, the tensile strength of the polypropylene composition of the present invention is greater than 35.97 MPa, the Izod notched impact strength is greater than 116.74 J / m, and no indentation occurs on the surface of the material, indicating that the polypropylene composition of the present invention has excellent mechanical properties and heat resistance stability.

[0097] The polypropylene compositions prepared by Examples 1-13 all have high mechanical properties and good surface appearance, ensuring that the blended materials prepared by PP and PC have good stability and synergistic enhancement in performance. After multiple tests, no matter what type of PP (copolymer, homopolymer) and PC materials are, they can obtain good compatibility under the new formula system with the addition of compatibilizer and tackifying resin.

[0098] It can be seen from the comparison of Comparative Examples 1-2 with Example 1 that the compatibilizer and tackifying resin of the present invention are both indispensable, and the compatibility effect is significantly reduced if one of them is missing.

[0099] It can be seen from the comparison of Comparative Examples 3-4 with Example 1 that if the amount of terpene resin is not within the range specified in the present invention, it will affect the overall compatibility of the materials to a certain extent, thereby reducing the synergistic effect.

[0100] From the comparison between Examples 3-4 and Example 13, it can be seen that the softening point of the terpene resin also affects the reinforcing effect of the prepared material. When the softening point of the terpene resin is 85-100°C, the mechanical properties are relatively increased, and the surface defects are less. When the softening point of the terpene resin exceeds 100°C, the overall compatibility of the material is affected, which is reflected in the appearance of a small amount of water marks on the surface of the injection molded part. The reason is that during the injection molding process, when the two streams meet, due to the influence of compatibility, the contact surface is not completely fused.

[0101] By comparing Examples 4-7 with Examples 1-2, it can be seen that the compatibilizer is compounded with polyethylene grafted maleic anhydride and polypropylene grafted maleic anhydride in a mass ratio, and the mass ratio of the two is controlled to be 1: (1-1.5), which is beneficial to improving the tensile strength and impact strength of the polypropylene composition, so that the polypropylene composition has excellent mechanical properties.

[0102] By comparing Example 12 with Example 1, it can be seen that the surface of the tackifying resin is pretreated with a silane coupling agent, which can effectively improve the overall performance of the material, and when the molded parts are injection molded, its surface has a gloss similar to that of PC materials. The introduction of silane coupling agents in the tackifying resin and PP / PC blending system is not just a simple physical bridge, but promotes molecular-level interactions. Through its unique molecular structure, the silane coupling agent can form a dense film with specific chemical activity on the surface of the tackifying resin. This film not only enhances the chemical affinity between the tackifying resin and the PP / PC matrix, but also promotes the entanglement and rearrangement of molecular chains in the interface region, forming a highly fused interface layer. This interface fusion not only improves the mechanical strength of the material, but also optimizes the scattering and reflection behavior of light on the surface of the material, thereby giving the material a higher gloss.

[0103] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A polypropylene composition, characterized in that The composition comprises the following components in parts by weight: 48-66 parts of polypropylene resin; 7-14 parts of polycarbonate; 1-7 parts of compatibilizer; 2-12 parts of tackifying resin.

2. The polypropylene composition according to claim 1, characterized in that The compatibilizer includes at least one of polyethylene grafted maleic anhydride and polypropylene grafted maleic anhydride.

3. The polypropylene composition according to claim 2, characterized in that The compatibilizer includes polyethylene grafted maleic anhydride and polypropylene grafted maleic anhydride, and the mass ratio of the polyethylene grafted maleic anhydride to the polypropylene grafted maleic anhydride is 1:(1-1.5).

4. The polypropylene composition according to claim 1, characterized in that The tackifying resin is a terpene resin, and the softening point of the terpene resin is 85-110°C.

5. The polypropylene composition according to claim 1, characterized in that The surface of the tackifying resin is pretreated with a silane coupling agent.

6. The polypropylene composition according to claim 1, characterized in that The polypropylene composition comprises the following components in parts by weight: Polypropylene 50-65 parts; polycarbonate 8-12 parts; compatibilizer 2-6 parts; tackifying resin 3-10 parts.

7. The polypropylene composition according to claim 1, characterized in that The polypropylene composition further comprises 0-10 parts of filler and 0-6 parts of auxiliary agent.

8. The polypropylene composition according to claim 7, characterized in that The filler includes calcium carbonate; the auxiliary agent includes a lubricant and a nucleating agent.

9. The method for preparing the polypropylene composition according to any one of claims 1 to 8, characterized in that: The following steps are involved: After the components are uniformly mixed, they are added into a twin-screw extruder, melt-kneaded, extruded and granulated to obtain a polypropylene composition.

10. Use of the polypropylene composition according to any one of claims 1 to 8 in automobile accessories.

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