High-gloss high-impact-resistance polypropylene composition and preparation method thereof

Abstract

The invention belongs to the technical field of high polymer materials, and particularly relates to a high-gloss and high-impact-resistance polypropylene composition and a preparation method thereof. The high-gloss and high-impact-resistance polypropylene composition comprises the following raw materials in percentage by weight: 70-92% of impact-resistance co-polypropylene; 5-20% of linear low density polyethylene; and 3-10% of an elastomer. The prepared high-gloss and high-impact-resistance polypropylene composition has high gloss, high impact resistance and good stress cracking resistance, the impact strength of a simply supported beam notch is 10-30 kJ / m < 2 >, the bending elastic modulus is 1000-1300 MPa, the glossiness is 80% or above, and the high-gloss and high-impact-resistance polypropylene composition can be applied to injection molding products with high requirements for the glossiness and the impact resistance and can be widely applied to injection molding products with high requirements for the glossiness and the impact resistance. And the produced product has the advantages of high gloss, high impact resistance, good rigid-tough balance and the like, and also has the advantage of good stress cracking resistance at the same time, such as plastic parts of household products, children toys, automobiles, motorcycles and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer materials, and particularly relates to a high-gloss and high-impact polypropylene composition and a preparation method thereof. Background Art

[0002] Polypropylene (PP) boasts low density, excellent mechanical properties, good heat resistance, and high chemical stability. It is currently one of the most widely used general-purpose plastics, widely used in home furnishings, automobiles, pipelines, medical applications, and other fields. As PP's application in various fields continues to deepen, the requirements for its performance continue to increase, including high rigidity, high impact resistance, high fluidity, and high gloss.

[0003] Existing technologies for developing high-gloss, high-impact polypropylene primarily focus on adding inorganic fillers to enhance gloss and toughening agents to improve impact resistance. Patent CN106750922A discloses a stress-whitening-resistant, high-resilience modified polypropylene composite material and its preparation method. The stress-whitening-resistant, high-resilience modified polypropylene composite material comprises the following ingredients: 60-85% PP resin, 6-20% elastomer, 5-15% PE resin, 0-4% compatibilizer, 0-5% inorganic filler, 0.2-0.8% antioxidant, and 0.8-1.5% processing aid. The composite material offers low cost, high impact resistance, stress-whitening resistance, and high resilience. However, the addition of inorganic fillers often negatively impacts impact resistance, and the addition of conventional toughening agents can also affect gloss, preventing the final product from achieving simultaneous improvements in both gloss and impact resistance. Patent CN110903549A discloses a polypropylene composite material, its preparation method, and application. The composite material comprises the following raw materials in parts by weight: 55-95 parts of polypropylene, 3-25 parts of polyethylene, 5-25 parts of TPE (thermoplastic elastomer), and 0-15 parts of TPV (thermoplastic vulcanizate). The polypropylene is a mixture of homopolymer polypropylene and random copolymer polypropylene. The composite material is prepared by melt extrusion and granulation of the uniformly mixed component mixture. It has excellent low-temperature impact toughness, good transparency, and stress whitening resistance, but its glossiness still needs to be improved. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the present invention aims to provide a high-gloss and high-impact polypropylene composition, which has high gloss, high impact resistance, and good stress cracking resistance, and a simple supported beam notched impact strength of 10-32 kJ / m 2, with a flexural elastic modulus of 1000-1300MPa and a glossiness of over 80%. It can be used for injection molded products with high requirements for glossiness and impact resistance, such as household products, children's toys, automobiles, motorcycles and other plastic parts. The products produced have the advantages of high gloss, high impact resistance, good balance of rigidity and toughness, and also have the advantage of good resistance to stress cracking;

[0005] Another object of the present invention is to provide a high-gloss and high-impact polypropylene composition and a preparation method thereof, which is scientific, reasonable, simple and easy to implement.

[0006] The technical solutions adopted by the present invention are as follows:

[0007] The high-gloss and high-impact polypropylene composition comprises the following raw materials in percentage by weight:

[0008] Impact copolymer polypropylene: 70-92%;

[0009] Linear low-density polyethylene: 5-20%;

[0010] Elastomers: 3-10%.

[0011] The melt mass flow rate of the impact copolymer polypropylene is 2-30 g / 10 min, and the weight average molecular weight is (20-50)×10 4 , preferably (30-50)×10 4 , molecular weight distribution is 3-7, preferably 4-6.

[0012] The impact-resistant copolymer polypropylene comprises ethylene as a comonomer, with a copolymer monomer content of 5-9%, preferably 6-8%, a rubber phase content of 15-20%, and a rubber phase particle size of 200-400 nm. Appropriate ethylene content, rubber phase content, and rubber phase particle size and morphology can help maintain the composition's high impact resistance and high gloss.

[0013] The melt mass flow rate of the linear low-density polyethylene is 15-25 g / 10 min and the density is 0.920-0.925 g / cm 3 The molecular weight distribution is 3-6, preferably 3-5, and hexene is used as a comonomer, with a co-hexene monomer content of 1-5%. The selection of this component can increase the impact resistance and comprehensive toughness and toughness of the composition, and has good melt mixing in the composition, which promotes further increase in gloss.

[0014] The elastomer is a copolymer of propylene and α-olefin, with a melt mass flow rate of 3-10 g / 10 min, preferably 5-7 g / 10 min, and a density of 0.860-0.870 g / cm 3The amount is 3-10%, preferably 4-7%. The selection of the elastomer can increase the impact resistance of the composition, has good compatibility with the polypropylene matrix, and further increases the glossiness.

[0015] The α-olefin is one or more of ethylene, butene or octene, preferably ethylene.

[0016] The density of the high gloss and high impact resistant polypropylene composition is 0.890-0.920 g / cm 3 , simply supported beam notched impact strength is 10-32kJ / m 2 , the bending elastic modulus is 1000-1300MPa, and the glossiness is above 80%.

[0017] The method for preparing the high-gloss and high-impact polypropylene composition comprises the following steps: mixing the formulated amount of impact-resistant copolymerized polypropylene, linear low-density polyethylene and elastomer in a high-speed mixer for 3-5 minutes, mixing them evenly, extruding them through a twin-screw extruder, and granulating them to obtain the high-gloss and high-impact polypropylene composition.

[0018] The screw extrusion temperature is 160-240°C.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] (1) The present invention develops a high-gloss and high-impact polypropylene composition formula by screening the composition formula, analyzing and characterizing the basic physical properties, and examining the processing and use performance. By selecting a polypropylene resin with a special structure and combining it with two other polymers, a polypropylene composition with high gloss and high impact resistance is obtained;

[0021] (2) The high-gloss and high-impact polypropylene composition of the present invention has a high gloss of more than 80%, which makes the surface of the plastic product bright and has a good visual effect, thereby improving the aesthetics and grade of the product; the simply supported beam notched impact strength is 10-32 kJ / m 2 , ensuring that the product has high impact resistance when subjected to external impact, is not easily damaged, and improves the durability of the product; good stress cracking resistance makes the product more stable and reliable during actual use; the bending elastic modulus is 1000-1300MPa, which makes the product have a good balance of rigidity and toughness; the high-gloss and high-impact polypropylene composition can be used to make injection molded products with high requirements for gloss and impact resistance, such as household products, children's toys, automobiles, motorcycles and other plastic parts, and has broad application prospects;

[0022] (3) The preparation method of the high-gloss and high-impact polypropylene composition described in the present invention is scientific, reasonable, green, environmentally friendly, simple and easy to implement. DETAILED DESCRIPTION

[0023] The present invention is further described below with reference to the following examples, but they do not limit the implementation of the present invention.

[0024] Unless otherwise specified, the raw materials used in the examples and comparative examples are conventional commercially available products.

[0025] in:

[0026] The melt mass flow rate of impact copolymer polypropylene 1 is 8 g / 10 min, and the weight average molecular weight is 25×10 4 , molecular weight distribution is 6, ethylene is used as comonomer, the copolymer ethylene monomer content is 7.1%, the rubber phase content is 17.8%, and the rubber phase particle size is 300±100nm;

[0027] The melt mass flow rate of impact copolymer polypropylene 2 is 28 g / 10 min, and the weight average molecular weight is 20×10 4 , molecular weight distribution is 6.3, ethylene is used as comonomer, the copolymer ethylene monomer content is 7.5%, the rubber phase content is 18.9%, and the rubber phase particle size is 300±100nm;

[0028] The melt mass flow rate of impact copolymer polypropylene 3 is 10 g / 10 min and the weight average molecular weight is 22×10 4 , molecular weight distribution is 5.9, ethylene is used as comonomer, the copolymerized ethylene monomer content is 13%, the rubber phase content is 26.7%, and the rubber phase particle size is 600±200nm;

[0029] The melt mass flow rate of impact copolymer polypropylene 4 is 11 g / 10 min, and the weight average molecular weight is 21×10 4 , molecular weight distribution is 5.6, ethylene is used as comonomer, the copolymerized ethylene monomer content is 4%, the rubber phase content is 15.3%, and the rubber phase particle size is 300±100nm;

[0030] The melt mass flow rate of linear low-density polyethylene 1 is 20 g / 10 min and the density is 0.924 g / cm 3 , molecular weight distribution is 4.5, hexene is used as comonomer, and the content of co-hexene monomer is 2.6%;

[0031] The melt mass flow rate of linear low-density polyethylene 2 is 2 g / 10 min and the density is 0.920 g / cm 3 , molecular weight distribution is 4.7, hexene is used as comonomer, and the content of copolymerized hexene monomer is 2.6%;

[0032] Elastomer 1 is a copolymer of propylene and ethylene with a melt mass flow rate of 5.2 g / 10 min and a density of 0.863 g / cm 3 ;

[0033] Elastomer 2 is a copolymer of propylene and ethylene with a melt mass flow rate of 10 g / 10 min and a density of 0.862 g / cm 3 .

[0034] Example 1

[0035] The high-gloss and high-impact polypropylene composition comprises the following raw materials in percentage by weight:

[0036] Impact copolymer polypropylene 1: 85%;

[0037] Linear low-density polyethylene 1:10%;

[0038] Elastomer 1:5%.

[0039] The method for preparing the high-gloss and high-impact polypropylene composition comprises the following steps: mixing the formulated amount of impact-resistant copolymerized polypropylene, linear low-density polyethylene, and elastomer in a high-speed mixer for 5 minutes to uniformly mix, extruding and granulating through a twin-screw extruder to obtain the high-gloss and high-impact polypropylene composition. The screw extrusion temperature is 160°C in the first section, 170°C in the second section, 190°C in the third section, 210°C in the fourth section, 220°C in the fifth section, and 240°C in the sixth section.

[0040] Example 2

[0041] The high-gloss and high-impact polypropylene composition comprises the following raw materials in percentage by weight:

[0042] Impact copolymer polypropylene 1: 77%;

[0043] Linear low-density polyethylene 1: 20%;

[0044] Elastomer 1:3%.

[0045] The preparation method of the high-gloss and high-impact polypropylene composition is the same as that in Example 1.

[0046] Example 3

[0047] The high-gloss and high-impact polypropylene composition comprises the following raw materials in percentage by weight:

[0048] Impact copolymer polypropylene 1: 80%;

[0049] Linear low-density polyethylene 1:10%;

[0050] Elastomer 1: 10%.

[0051] The preparation method of the high-gloss and high-impact polypropylene composition is the same as that in Example 1.

[0052] Example 4

[0053] The high-gloss and high-impact polypropylene composition comprises the following raw materials in percentage by weight:

[0054] Impact copolymer polypropylene 1: 85%;

[0055] Linear low-density polyethylene 1:5%;

[0056] Elastomer 1: 10%.

[0057] The preparation method of the high-gloss and high-impact polypropylene composition is the same as that in Example 1.

[0058] Example 5

[0059] The high-gloss and high-impact polypropylene composition comprises the following raw materials in percentage by weight:

[0060] Impact copolymer polypropylene 2: 92%;

[0061] Linear low-density polyethylene 1:5%;

[0062] Elastomer 2:3%.

[0063] The preparation method of the high-gloss and high-impact polypropylene composition is the same as that in Example 1.

[0064] Example 6

[0065] The high-gloss and high-impact polypropylene composition comprises the following raw materials in percentage by weight: impact-resistant copolymer polypropylene 2: 75%;

[0066] Linear low-density polyethylene 1: 20%;

[0067] Elastomer 2: 5%.

[0068] The preparation method of the high-gloss and high-impact polypropylene composition is the same as that in Example 1.

[0069] Example 7

[0070] The high-gloss and high-impact polypropylene composition comprises the following raw materials in percentage by weight:

[0071] Impact copolymer polypropylene 2: 85%;

[0072] Linear low-density polyethylene 1:10%;

[0073] Elastomer 2: 5%.

[0074] The preparation method of the high-gloss and high-impact polypropylene composition is the same as that in Example 1.

[0075] Example 8

[0076] The high-gloss and high-impact polypropylene composition comprises the following raw materials in percentage by weight:

[0077] Impact copolymer polypropylene 2: 80%;

[0078] Linear low-density polyethylene 1:10%;

[0079] Elastomer 2: 10%.

[0080] The preparation method of the high-gloss and high-impact polypropylene composition is the same as that in Example 1.

[0081] Comparative Example 1

[0082] The polypropylene composition comprises the following raw materials in percentage by weight:

[0083] Impact copolymer polypropylene 1: 100%;

[0084] Linear low-density polyethylene 1: 0%;

[0085] Elastomer 1:0%.

[0086] The preparation method of the polypropylene composition is the same as that in Example 1.

[0087] Comparative Example 2

[0088] The polypropylene composition comprises the following raw materials in percentage by weight:

[0089] Impact copolymer polypropylene 1: 80%;

[0090] Linear low-density polyethylene 1: 20%;

[0091] Elastomer 1:0%.

[0092] The preparation method of the polypropylene composition is the same as that in Example 1.

[0093] Comparative Example 3

[0094] The polypropylene composition comprises the following raw materials in percentage by weight:

[0095] Impact copolymer polypropylene 1:90%;

[0096] Linear low-density polyethylene 1: 0%;

[0097] Elastomer 1: 10%.

[0098] The preparation method of the polypropylene composition is the same as that in Example 1.

[0099] Comparative Example 4

[0100] The polypropylene composition comprises the following raw materials in percentage by weight:

[0101] Impact copolymer polypropylene 1: 60%;

[0102] Linear low-density polyethylene 1: 25%;

[0103] Elastomer 1: 15%.

[0104] The preparation method of the polypropylene composition is the same as that in Example 1.

[0105] Comparative Example 5

[0106] The polypropylene composition comprises the following raw materials in percentage by weight:

[0107] Impact copolymer polypropylene 1: 75%;

[0108] Linear low-density polyethylene 2: 20%;

[0109] Elastomer 1:5%.

[0110] The preparation method of the polypropylene composition is the same as that in Example 1.

[0111] Comparative Example 6

[0112] The polypropylene composition comprises the following raw materials in percentage by weight:

[0113] Impact copolymer polypropylene 3: 75%;

[0114] Linear low-density polyethylene 1: 20%;

[0115] Elastomer 1:5%.

[0116] The preparation method of the polypropylene composition is the same as that in Example 1.

[0117] Comparative Example 7

[0118] The polypropylene composition comprises the following raw materials in percentage by weight:

[0119] Impact copolymer polypropylene 4: 75%;

[0120] Linear low-density polyethylene 1: 20%;

[0121] Elastomer 1:5%.

[0122] The preparation method of the polypropylene composition is the same as that in Example 1.

[0123] Comparative Example 8

[0124] The polypropylene composition comprises the following raw materials in percentage by weight:

[0125] Impact copolymer polypropylene 4: 85%;

[0126] Linear low-density polyethylene 1: 15%;

[0127] Elastomer 1:0%.

[0128] The preparation method of the polypropylene composition is the same as that in Example 1.

[0129] Performance testing:

[0130] Conditioning of specimens and standard test environment: in accordance with the provisions of GB / T 2918-1998, the temperature is 23±2°C, the relative humidity is 50±5%, and the specimen conditioning time is based on the specific standards of the test items;

[0131] Melt flow rate (MFR): tested according to GB / T 3682-2000;

[0132] Tensile yield stress: tested according to GB / T 1040.2-2006, using 1A type specimens, and a tensile speed of 50 mm / min;

[0133] Charpy notched impact strength: tested according to GB / T 1043.1-2008, the room temperature treatment process is placed at 23°C and 50% humidity for 24 hours;

[0134] Flexural modulus: tested according to GB / T 9341-2008;

[0135] Glossiness: tested according to GB / T8807-1988;

[0136] Screw assembly crack resistance: Use a high-speed rotating electric assembly tool to assemble screws, observe whether the screw holes of the composite product crack, and examine the product's assembly crack resistance.

[0137] Main test instruments: melt flow rate tester, CEAST, Italy; universal material testing machine, ZWICK; gloss meter, 60° angle, BYK. Test results are shown in Tables 1-4.

[0138] Table 1 Composition and performance of Examples 1-4

[0139]

[0140] Table 2 Composition and performance of Examples 5-8

[0141]

[0142]

[0143] Table 3 Comparative Examples 1-4 Formulation Composition and Performance

[0144]

[0145] Table 4 Comparative Examples 5-8 formulation composition and performance

[0146]

[0147] It can be seen from Tables 1-4 that the performance and use effects of the high-gloss and high-impact polypropylene compositions prepared in Examples 1-8 can be seen that the high-gloss and high-impact polypropylene compositions prepared in Examples 1-8 have high gloss and high impact resistance, good stress cracking resistance, and good assembly properties through the screening and development of the formula.

[0148] The prepared high gloss and high impact resistant polypropylene composition has a density of 0.890-0.920 g / cm 3 , simply supported beam notched impact strength 10-32kJ / m 2 , bending elastic modulus 1000-1300MPa, glossiness greater than 80%, can be used for plastic parts of household products, children's toys, automobiles, motorcycles, etc., and has excellent crack resistance during assembly.

Claims

1. A high gloss and high impact resistant polypropylene composition, characterized in that: The following raw materials are included in weight percentage: Impact copolymer polypropylene: 70-92%; Linear low-density polyethylene: 5-20%; Elastomer: 3-10%.

2. The high gloss and high impact resistant polypropylene composition according to claim 1, characterized in that: The melt mass flow rate of the impact copolymer polypropylene is 2-30 g / 10 min, and the weight average molecular weight is (20-50)×10 4 , molecular weight distribution is 3-7.

3. The high gloss and high impact resistant polypropylene composition according to claim 1, characterized in that: The impact-resistant copolymer polypropylene uses ethylene as a copolymer monomer, the copolymer ethylene monomer content is 5-9%, the rubber phase content is 15-20%, and the rubber phase particle size is 200-400nm.

4. The high gloss and high impact resistant polypropylene composition according to claim 1, characterized in that: The melt mass flow rate of the linear low-density polyethylene is 15-25 g / 10 min, and the density is 0.920-0.925 g / cm 3 , molecular weight distribution is 3-6, hexene is used as the copolymer monomer, and the copolymer hexene monomer content is 1-5%.

5. The high gloss and high impact resistant polypropylene composition according to claim 1, characterized in that: The elastomer is a copolymer of propylene and α-olefin, with a melt mass flow rate of 3-10g / 10min and a density of 0.860-0.870g / cm 3 .

6. The high gloss and high impact polypropylene composition according to claim 5, characterized in that: The α-olefin is one or more of ethylene, butene or octene.

7. The high gloss and high impact polypropylene composition according to claim 1, characterized in that: The density of the high gloss and high impact resistant polypropylene composition is 0.890-0.920 g / cm 3 , simply supported beam notched impact strength is 10-32kJ / m 2 , the bending elastic modulus is 1000-1300MPa, and the glossiness is above 80%.

8. A method for preparing the high gloss and high impact polypropylene composition according to any one of claims 1 to 7, characterized in that: The steps are as follows: evenly mix the impact-resistant copolymer polypropylene, linear low-density polyethylene and elastomer in a prescribed amount, extrude and granulate through a twin-screw extruder, and obtain a high-gloss and high-impact-resistant polypropylene composition.

9. The method for preparing the high-gloss and high-impact polypropylene composition according to claim 8, characterized in that: The screw extrusion temperature is 160-240°C.

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