Polypropylene material as well as preparation method and application thereof

Abstract

The invention relates to a polypropylene material as well as a preparation method and application thereof, and belongs to the technical field of high polymer materials. The polypropylene material provided by the invention is prepared from the following components in parts by weight: 28 to 102 parts of polypropylene, 4.5 to 21 parts of LDPE (Low-Density Polyethylene), 0.15 to 2.5 parts of an anti-reflection agent, 9 to 31 parts of a flame retardant, 0.2 to 2.5 parts of a processing aid and 0.05 to 2.5 parts of an antioxidant, the anti-reflection agent comprises a sorbic acid alcohol transparent agent; the flame retardant comprises cyclic phosphate ester. According to the polypropylene material disclosed by the invention, the transparency, the flame retardance and the impact property of the polypropylene material are remarkably improved through compounding and synergy of the components.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer materials, and in particular relates to a polypropylene material and a preparation method and application thereof. Background Art

[0002] Polypropylene (PP) has the advantages of low density, high mechanical strength, good heat resistance, non-toxicity, easy processing, high temperature resistance, chemical resistance, easy availability of raw materials and low price. It has become one of the fastest growing varieties of commercial plastics, so it has a wide range of uses and is widely used in chemical, chemical fiber, home appliances, automobile and other fields. In recent years, with the rapid development of new energy vehicles, parts such as automotive interior ambient light light guide brackets and exterior bumpers have provided some innovative application scenarios for transparent polypropylene. At the same time, automotive electronic products and battery housings and other products with flame retardant requirements will also be potential application parts for transparent polypropylene due to the need for precision laser welding. Due to the opacity of conventional flame retardants, the application of PP is limited to a certain extent, resulting in its application in electronic products and other fields with flame retardant requirements.

[0003] The development of transparent impact-resistant PP has important industrial application value and market value. At present, transparent PP is mainly obtained by adding new catalysts during the polymerization process, or by adding nucleating agents through blending technology to achieve modification and transparency enhancement of PP to obtain transparent PP. The transparent polypropylene materials prepared by the above two methods generally have low impact properties. The most commonly used toughening agents for toughening and modifying PP are EPR and POE, etc. These toughening agents will affect the transparency of the material. If the nucleating agent is continued to be added, it is easy to cause the crystallization nucleation saturation of the material. After reaching a certain transparency, it is difficult to further improve the transparency. For the current transparency enhancement methods, it is difficult to take into account the transparency and high impact performance of high-transparency polypropylene materials at the same time. In addition, flame retardants are added to transparent PP for flame retardant modification. The flame retardant efficiency of inorganic flame retardants is low, and a large amount of addition is required, which will affect the transmittance and mechanical properties. High-efficiency halogen-containing flame retardants not only affect the transmittance, but also do not meet environmental protection requirements.

[0004] Therefore, it is of great significance to prepare a transparent, flame-retardant polypropylene material with good mechanical properties. Summary of the invention

[0005] The purpose of the present invention is to overcome the problems existing in the above-mentioned prior art and to provide a polypropylene material and a preparation method and application thereof.

[0006] The present invention is achieved through the following technical solutions:

[0007] In a first aspect, the present invention provides a polypropylene material, comprising the following components by weight: 28-102 parts of polypropylene, 4.5-21 parts of LDPE, 0.15-2.5 parts of a permeability enhancer, 9-31 parts of a flame retardant, 0.02-2.5 parts of a processing aid, and 0.05-2.5 parts of an antioxidant;

[0008] The permeability enhancer includes a sorbitol-based transparent agent; and the flame retardant includes a cyclic phosphate ester.

[0009] The polypropylene material of the present invention significantly improves the transparency, flame retardancy and impact performance of the polypropylene material through the synergistic combination of components. LDPE (low-density polyethylene) is added to the polypropylene material of the present invention as a rubber phase dispersed in the PP system to play a toughening role, improve the impact performance of the material, and at the same time, it destroys and refines the spherulite structure of PP together with the sorbitol-based transparent agent to improve the transparency; the cyclic phosphate flame retardant added to the polypropylene material of the present invention plays a flame retardant role through the flame-retardant group on the one hand, and on the other hand, through the form of chemical reaction under high temperature, the flame extinguishing, shearing, inhibition and other flame retardant mechanisms are combined to achieve the effect of synergistic flame retardant effect, and these flame retardant mechanisms enable the cyclic phosphate flame retardant to significantly reduce the burning speed of the material. Since the cyclic phosphate flame retardant has good adhesion, it can be fully dispersed in the material, and the excellent light transmission performance of the material can be maintained while the ductility and impact toughness of the material can be increased. LDPE, clarifier and flame retardant jointly destroy and refine the spherulite structure of PP to improve transparency, further optimize the ratio of flame retardant and LDPE, and ultimately achieve the simultaneous improvement of the impact performance, transparency and flame retardant properties of polypropylene materials.

[0010] Preferably, the polypropylene material comprises the following components by weight: 30-99.5 parts of polypropylene, 5-20 parts of LDPE, 0.2-2 parts of a permeability enhancer, 10-30 parts of a flame retardant, 0.1-2 parts of a processing aid, and 0.1-2 parts of an antioxidant.

[0011] Preferably, the mass ratio of the LDPE to the permeability enhancer is (7-26):1; more preferably, the mass ratio of the LDPE to the permeability enhancer is (10-20):1.

[0012] The simultaneous addition of LDPE and sorbic acid alcohol-based transparent agents can significantly improve the light transmittance of polypropylene materials. Furthermore, when the mass ratio between the two is (7-26):1, the synergistic effect between the two can be fully exerted, so that the polypropylene material has better transparency, impact resistance and flame retardant properties; more preferably (10-20):1.

[0013] In the present invention, the mass ratio of LDPE to the permeability enhancer is any one of or both of 7:1, 10:1, 12:1, 15:1, 18:1, 20:1, 25:1, and 26:1.

[0014] Preferably, the density of the LDPE is 0.91 g / cm 3 -0.93g / cm 3 More preferably, the density of the LDPE is 0.91 g / cm 3 -0.92g / cm 3 .

[0015] The density of LDPE will affect the refractive index of LDPE, and thus affect the transparency of the polypropylene material. Preferably, the density of the LDPE is 0.91 g / cm 3 -0.93g / cm 3 , LDPE with this density can further reduce the refraction loss of light and improve the transparency of polypropylene materials; at the same time, the addition of LDPE can improve the impact performance of the material. The density of LDPE is measured by ISO1183-1:2019 at a constant temperature of 23°C.

[0016] Preferably, the polypropylene has a melt flow rate of 1-100 g / 10 min at 230° C. and a weight of 2.16 kg according to ISO 1133-2012.

[0017] Optionally, in the polypropylene material, the mass percentage of the polypropylene is not less than 60%.

[0018] Preferably, the cyclic phosphate comprises phosphophanate-based cyclic phosphate.

[0019] Phosphophanate cyclic phosphates are cyclic phosphates containing a phosphophanate ring structure. When burned, they can decompose to produce compounds such as phosphoric acid and phosphate esters. These compounds can promote the carbonization process of polypropylene and form a dense carbon layer, thereby isolating oxygen and heat sources to achieve a flame retardant effect. At the same time, since the molecular structure of phosphophanate cyclic phosphates is relatively regular and evenly dispersed in polypropylene, no obvious scattering center or absorption center will be formed, so it will not have a significant impact on the light transmittance of polypropylene, and can maintain its transparency while improving its flame retardant properties.

[0020] Preferably, the phosphophanate-based cyclic phosphate includes flame retardant DDP.

[0021] The chemical name of the flame retardant DDP is [(6-oxy-(6H)-dibenzo-(CE)(1,2)-oxophosphorus-6-one)methyl]-succinic acid. It produces very low smoke and toxic gases and has excellent flame retardancy.

[0022] Preferably, the sorbic acid alcohol-based transparent agent includes at least one of 1,2,3-trideoxy-4,6:5,7-bis-O-[(4-propylphenyl)methylene]-nonanol and 1,3:2,4-di(3,4-dimethylbenzylidene)-D-sorbitol.

[0023] Preferably, the antioxidant includes at least one of a phenolic antioxidant, an amine antioxidant, and a phosphite antioxidant.

[0024] Preferably, the processing aid includes a lubricant, and the lubricant includes at least one of a stearate lubricant, a stearate lubricant, and an amide lubricant.

[0025] In a second aspect, the present invention provides a method for preparing the polypropylene material, comprising the following steps:

[0026] (1) mixing all components uniformly to obtain a premix;

[0027] (2) placing the premix obtained in step (1) in a twin-screw extruder, performing melt mixing, and extruding and granulating to obtain the polypropylene material.

[0028] The preparation method of the polypropylene material of the present invention is simple and can realize industrial-scale production.

[0029] Preferably, the processing temperature of the twin-screw extruder is 80° C.-200° C., and the main engine speed is 400-600 rpm.

[0030] In a second aspect, the present invention provides application of the polypropylene material in automotive interior and exterior parts.

[0031] The polypropylene material of the present invention has excellent transparency, flame retardancy and impact resistance, and is very suitable for automotive interior and exterior parts, such as automotive dashboards, ambient lights, ambient light guide brackets, and headlights.

[0032] The present invention has the following beneficial effects: the flame retardant of the present invention includes cyclic phosphate ester, which, on the one hand, exerts a flame retardant effect, and on the other hand, through the form of chemical reaction under high temperature, combines flame extinguishing, shearing, inhibition and other flame retardant mechanisms together to achieve a synergistic flame retardant effect. These flame retardant mechanisms enable the cyclic phosphate ester flame retardant to significantly reduce the burning rate of the material. Since the cyclic phosphate ester flame retardant has good adhesion, it can be fully dispersed in the material, while maintaining the excellent light transmittance of the material, it can also increase the ductility and impact toughness of the material, and can overcome the defect of poor light transmittance of flame retardant polypropylene materials in the prior art. At the same time, by optimizing the ratio between LDPE, flame retardant and transmittance enhancer, the transparency, impact resistance and flame retardant effect of the polypropylene material can be improved at the same time. DETAILED DESCRIPTION

[0033] 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. It should be understood by those skilled in the art that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0034] Unless otherwise specified, the experimental methods used in the examples are all conventional methods; the materials, reagents, etc. used, unless otherwise specified, can be obtained from commercial channels.

[0035] Examples 1-12

[0036] The components of the polypropylene material described in the embodiment of the present invention are shown in Table 1.

[0037] The method for preparing the polypropylene material comprises the following steps:

[0038] (1) putting polypropylene, LDPE, a permeability enhancer, a flame retardant, an antioxidant and a processing aid into a high-speed mixer according to the above weight proportions, and mixing at a speed of 400 r / min for 5 min to obtain a premix;

[0039] (2) placing the premix obtained in step (1) in a twin-screw extruder, melt-mixing, and extruding and granulating to obtain the polypropylene material; wherein the processing temperature of each section of the twin-screw extruder is: 80° C. in zone 1, 180° C. in zones 2 to 9, and 200° C. in zone 10; and the screw speed of the twin-screw extruder is 500 r / min.

[0040] Comparative Examples 1-4

[0041] The difference between the comparative examples and the embodiments is only in the types and proportions of components, as shown in Table 2.

[0042] Among the components described in the embodiments and comparative examples,

[0043] Polypropylene-1: PP Z30S, Ningbo Jinfa, melt flow rate at 230℃, 2.16kg weight is 29.6g / 10min;

[0044] Polypropylene-2: PP HP500N, Ningbo Jinfa; melt flow rate at 230°C and 2.16 kg weight is 10.5 g / 10 min;

[0045] Polypropylene-3: PP BX3920, Sino-Korea Petrochemical; melt flow rate at 230°C and 2.16 kg weight is 100 g / 10 min;

[0046] LDPE-1: density 0.915g / cm 3 , LDPE LA 0710, Arkema, France;

[0047] LDPE-2: density 0.917 g / cm 3 , LDPE LB7000, LG Chem;

[0048] Transparent agent-1: 1,2,3-trideoxy-4,6:5,7-bis-O-[(4-propylphenyl)methylene]-nonanol, transparent agent NX8000, Milliken & Company;

[0049] Permeabilizer-2: 1,3:2,4-di(3,4-dimethylbenzylidene)-D-sorbitol, HX3, Alpha Chemical;

[0050] Permeability enhancer-3: substituted aryl phosphate nucleating agent, TMP-6, Zhongshan Borun Trading;

[0051] Flame retardant-1: phosphophanate cyclic phosphate, DOPO-DDP, Hanfeng Technology;

[0052] Flame retardant-2: cyclic phosphate ester, CAS No. 4090-51-1, Sandoflam 5060, Sandon Company, Switzerland;

[0053] Flame retardant-3: triphenyl phosphate, BT, purchased from Wuhan Profo;

[0054] Antioxidant: Antioxidant 1010 and 168 were purchased from BASF in a 1:1 mixture;

[0055] Processing aids: zinc stearate, purchased from Cytec;

[0056] 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.

[0057] Table 1 Content of each component in the materials of Examples 1-12 (parts)

[0058]

[0059]

[0060] Table 2 Content of each component in the materials of Comparative Examples 1-4 (parts)

[0061] Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Polypropylene-1 80 80 80 80 LDPE-1 7.5 7.5 7.5 Permeability enhancer-1 0.5 0.5 Transparent Agent-3 0.5 Flame retardant-1 15 15 15 Flame retardant-3 15 Processing Aids 0.3 0.3 0.3 0.3 Antioxidants 0.3 0.3 0.3 0.3

[0062] In order to verify the performance of the polypropylene material of the present invention, the material pellets prepared in each embodiment and comparative example were used to evaluate the impact performance, transparency and flame retardancy of the material using ISO standard mold sample impact specimens and 3mm thick smooth color plates and flame retardant specimens, as follows:

[0063] Izod notched impact strength: Test standard ISO 180 / 1eA-2010, sample size 80×10×4mm, A-type notch.

[0064] Light transmittance: Test standard GB / T 2410-2008;

[0065] Vertical burning test: The UL-94 grade of the material is tested by a vertical burning tester, the sample size is 100mm×13mm×3.2mm, and the test standard is GB / T2408-2008.

[0066] Limiting oxygen index test (LOI): The limiting oxygen index of PP composite materials containing different proportions of IFR was tested by an oxygen index analyzer, and the sample size was 100mm×6.5mm×3.2mm. The test standard is GB / T2406-93.

[0067] The test results are shown in Tables 3 and 4.

[0068] Table 3 Material performance test results of Examples 1-12

[0069]

[0070]

[0071] Table 4 Material performance test results of comparative examples 1-4

[0072] Test items Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 <![CDATA[Izod impact strength of cantilever beam, kJ / m 2 > 2.9 4.6 4.9 4.2 Light transmittance, % 53.1 45.3 61.2 25.7 Vertical burning (flame retardant) V0 V0 V0 V1 Oxygen Index 24.3 23.9 24.5 19.7

[0073] As can be seen from Table 3 and Table 4, the polypropylene materials of Examples 1-12 of the present invention have excellent flame retardancy, transparency and impact resistance, with a vertical combustion grade of V0, an oxygen index of not less than 22, a light transmittance of not less than 69%, and an impact strength of not less than 4.7 kJ / m 2 .

[0074] In Comparative Example 1, LDPE was not added, resulting in an overall decrease in the performance of the material, which seriously affected the impact performance of the material. In Comparative Example 2, no transmittance enhancer was added, and the light transmittance of the material was significantly reduced. It can be seen from Comparative Examples 1 and 2 that the simultaneous addition of LDPE and sorbitol-type transparent agents significantly improved the light transmittance of the material. When the two components are combined and added to polypropylene, there is a certain synergistic effect between the components in terms of light transmittance, and the improvement in light transmittance is significantly better than the effect of adding a single component. In Comparative Example 3, no sorbitol-type transparent agent was added, and the light transmittance of its polypropylene material was significantly lower than that of Example 1. In Comparative Example 4, ordinary organophosphate flame retardants were used, which not only failed to effectively improve the flame retardant properties of the material, but also greatly reduced the light transmittance of the material; indicating that the use of cyclic phosphate flame retardants in the present invention can make the impact performance, light transmittance and flame retardancy of polypropylene materials at an excellent level.

[0075] 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 material, characterized in that: The composition comprises the following components by weight: 28-102 parts of polypropylene, 4.5-21 parts of LDPE, 0.15-2.5 parts of permeability enhancer, 9-31 parts of flame retardant, 0.02-2.5 parts of processing aid, and 0.05-2.5 parts of antioxidant; The permeability enhancer includes a sorbitol-based transparent agent; and the flame retardant includes a cyclic phosphate ester.

2. The polypropylene material according to claim 1, characterized in that: The mass ratio of the LDPE to the permeability enhancer is (7-26):

1.

3. The polypropylene material according to claim 1, characterized in that: The density of the LDPE is 0.91 g / cm 3 -0.93g / cm 3 .

4. The polypropylene material according to claim 1, characterized in that: The cyclic phosphates include phosphophanate-based cyclic phosphates.

5. The polypropylene material according to claim 1, characterized in that: The polypropylene has a melt flow rate of 1-100 g / 10 min at 230° C. and a weight of 2.16 kg according to ISO 1133-2012.

6. The polypropylene material according to claim 1, characterized in that: The sorbic acid alcohol-based transparent agent includes at least one of 1,2,3-trideoxy-4,6:5,7-bis-O-[(4-propylphenyl)methylene]-nonanol and 1,3:2,4-di(3,4-dimethylbenzylidene)-D-sorbitol.

7. The polypropylene material according to claim 1, characterized in that: The antioxidant includes at least one of a phenolic antioxidant, an amine antioxidant, and a phosphite antioxidant.

8. The polypropylene material according to claim 1, characterized in that: The processing aid includes a lubricant, and the lubricant includes at least one of a stearate lubricant, a stearate lubricant, and an amide lubricant.

9. The method for preparing the polypropylene material according to any one of claims 1 to 8, characterized in that: The following steps are involved: (1) mixing all components uniformly to obtain a premix; (2) placing the premix obtained in step (1) in a twin-screw extruder, performing melt mixing, and extruding and granulating to obtain the polypropylene material.

10. Use of the polypropylene material according to any one of claims 1 to 8 in automotive interior and exterior parts.

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