CN116041856A - A high-gloss, high-impact, low-shrinkage weather-resistant polypropylene and its preparation method and application - Google Patents

Abstract

The invention discloses a high-gloss, high-impact, low-shrinkage weather-resistant polypropylene and its preparation method and application. The raw materials and their weight percentages are as follows: PP homopolymer 36-43%, PP copolymer resin 36-43%, metallocene elastic Body 4‑8%, PE resin 10‑20%, additives and toner 1‑1.5%. In the present invention, high-gloss copolymerization and homo-polypropylene are compounded, and a toughening agent is used at the same time. This kind of toughening agent is an ethylene-propylene elastomer polymerized by a metallocene catalyst, which will not affect the gloss of polypropylene, and breaks the high-gloss polypropylene that cannot be added. In the face of the toughening agent dilemma, a high-gloss, high-impact, low-shrinkage weather-resistant modified polypropylene material has been prepared. The notched impact strength is greater than 29kJ/m ² , and the gloss is 83. ATV panel.

Description

A kind of high gloss, high impact, low shrinkage weather-resistant polypropylene and its preparation method and application

Technical Field

The invention relates to the technical field of polymer materials, and in particular to high-gloss, high-impact, low-shrinkage, weather-resistant polypropylene and a preparation method and application thereof.

Background Art

The rise of high-gloss PP is to replace ABS because it is cheap and has much better weather resistance than ABS, but the first problem to be solved is good gloss. Homopolymer and random copolymer polypropylene belong to homogeneous systems with high gloss but poor impact strength. In order to meet the needs of various markets, polypropylene with both impact resistance and high gloss has become the main development direction. High-gloss copolymer polypropylene belongs to high-end polypropylene products. At present, domestic related research enterprises include Sinopec Zhenhai Refining and Chemical Branch, Sinopec Shanghai Petrochemical, Beijing Chemical Research Institute, etc. With the deepening of research, good results have been achieved. In the past three years, PP raw material manufacturers have produced a variety of high-gloss copolymer PP, including K7227H from Wuhan, China, ExxonMobil's 7123KN, EP548G from Tianjin SABIC, MG22 and MG15 from Maoming Petrochemical, M10RG from Zhenhai Refining and Chemical, and QCG10N from Qilu Petrochemical. In short, high-gloss copolymer PP needs to have both high gloss and medium impact strength. At present, the raw material PP cannot meet the needs of parts in the market, because the raw material PP has a large shrinkage rate, the size of the parts is unstable, and it has only medium impact strength and is not weather-resistant. Therefore, modified plastic is needed - a high-gloss, high-impact, low-shrinkage, weather-resistant polypropylene.

After searching, the Chinese patent with publication number CN201611173288.8 proposed a high-gloss, high-black, high-impact polypropylene with a glossiness of 82.8-90.2 and an Izod impact strength of only 2.6-3.6 kJ/m ² .

After searching, a Chinese patent with publication number CN201010140289.9 proposed a high-gloss, easy-to-form polypropylene material with a glossiness of 84-89. It used bimodal polypropylene, in which the glossiness of the bimodal polypropylene raw material was 89, and did not involve the impact strength of the material.

After searching, the Chinese patent with publication number CN201710166972.1 proposed a high-gloss spray-free polypropylene composite material without inorganic fillers. Both gloss and impact strength reached the highest values at the same time, with a gloss of 89 and an impact strength of 8.5 kJ/m ² .

After searching, the Chinese patent with publication number CN202210294305.2 proposed a polypropylene with high gloss, low shrinkage and medium impact strength. Because there is no elastomer toughening, and also because it is found through experiments that inorganic fillers including barium sulfate not only cannot improve the gloss of polypropylene, but also reduce the gloss of polypropylene, but barium sulfate reduces the gloss of polypropylene less than calcium carbonate and talcum powder. POE and PE also reduce the gloss of polypropylene. In addition, the effect of nucleating agents, brighteners, and brighteners on increasing the surface gloss of parts is very limited.

The market demand for high-gloss and high-impact polypropylene is huge, especially in the field of home appliance panels. Now, beach car panels are also used in large quantities, and there are also weather resistance requirements. In the preparation of such materials, the selection of polypropylene raw materials is the key, covering homopolymerization, block copolymerization and random copolymerization, covering all categories of commercial polypropylene materials. We can only keep searching for raw material varieties. The existing polypropylene gloss results are as follows:

Brand Z30S K7227H K8003 R380Y M800E K8009 HX3800 Glossiness 83 79 55 82 82 73 82 Brand ST30 EA260 hp544t R370Y 7123KN K7926 BX3900 Glossiness 89 83 85 82 82 68 82

Random copolymer and homopolymer polypropylene have low impact strength, and the glossiness is as high as 82 or above. ExxonMobil's high-grade polypropylene 7123KN, which has just been launched on the market, has a glossiness of 82, and SK's HX3800 and BX3900 can also reach 82. The prices of the three imported materials are high. The K7227H obtained from Wuhan Ethylene in the raw material screening has an unexpectedly high glossiness of 79, which is cost-effective and is the first choice for preparing high-gloss, high-impact and weather-resistant polypropylene. At the same time, the use of PE materials to reduce the recovery rate is also unexpected. PE materials basically do not reduce the gloss, and only metallocene PE will reduce the gloss. And our team has also broken through the difficulty of not being able to add elastomers to toughen high-gloss polypropylene, and obtained metallocene elastomer toughening without reducing the gloss.

Summary of the invention

Based on the technical problems existing in the background technology, the present invention proposes a high-gloss, high-impact, low-shrinkage, weather-resistant polypropylene and a preparation method and application thereof.

The invention provides a high-gloss, high-impact, low-shrinkage weather-resistant polypropylene, whose raw materials and weight percentages are as follows: 36-43% PP homopolymer, 36-43% PP copolymer resin, 4-8% metallocene elastomer, 10-20% PE resin, and 1-1.5% additives and color powder.

Preferably, the PP copolymer resin is a block copolymer resin with an impact strength of >9 KJ/ ^{m2 and} a glossiness (60°) of >79.

Preferably, the metallocene toughening agent is a metallocene ethylene propylene elastomer.

Preferably, the PE is PE polymerized by a conventional catalyst, rather than PE polymerized by a metallocene catalyst.

Preferably, the auxiliary agents include antioxidant 1010, antioxidant 168, light stabilizer, and lubricant PE wax.

Preferably, the color powder is a sun-resistant, heat-resistant and weather-resistant color powder.

The invention provides a method for preparing high-gloss and high-toughness weather-resistant polypropylene, comprising the steps of adding the PP resin, toughening agent, auxiliary agent and color powder into a high-speed stirrer according to their respective weight percentages and mixing them evenly to obtain a mixture, and then adding the mixture into a twin-screw extruder for melt extrusion.

Preferably, the extrusion temperature of the twin-screw extruder is 180-200° C., and the screw speed is 300-500 rpm.

The invention provides an application of high-gloss, high-impact, low-shrinkage weather-resistant polypropylene for injection molding of a panel of a beach vehicle.

The beneficial effects of the present invention are:

1. Domestic polypropylene K7227H is selected as the PP copolymer resin component, which has a high gloss of 79 and a notched cantilever beam impact strength of 9.6kJ/ ^m2. When compounded with homopolymer polypropylene, high-priced random copolymer or imported polypropylene can be omitted.

2. Screen out PE polymerized by domestic BSG catalyst to reduce the shrinkage of PP and toughen PP without reducing gloss. Imported metallocene catalyst polyethylene has the opposite effect, greatly reducing gloss.

3. No need for expensive nucleating agents to increase gloss, polypropylene K7227H or domestic BX3500 or domestic BX3800 originally added nucleating agents during polymerization. This avoids poor dispersion of nucleating agents and poor gloss enhancement effects, and also reduces costs.

4. The most important thing is to use metallocene ethylene propylene elastomer to toughen PP without reducing the gloss, so as to obtain high impact strength and low shrinkage.

DETAILED DESCRIPTION

The technical solutions in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

The raw materials used in the following examples and comparative examples are described as follows, but are not limited to these materials:

Homopolymer polypropylene, brand name ST30, was purchased from Sino-Korea Wuhan Petrochemical.

Block copolymer polypropylene, brand K7227H, room temperature Izod notched impact strength of 9.6 KJ/m ² , glossiness 79, BX3500 domestically produced, room temperature Izod notched impact strength of 5.7 KJ/m ² , glossiness 82, purchased from Sino-Korea Wuhan Petrochemical.

Linear low-density polyethylene 1, LLDPE EGM-38, 2.16KG melt mass flow rate at 190°C and 14g/10min, was purchased from Wuhan Sino-Korean Petrochemical.

Linear low density polyethylene 2, metallocene catalyst polyethylene, LLDPE EXCEED 1018MA, 2.16KG at 190°C, melt mass flow rate of 1g/10min, purchased from ExxonMobil.

Elastomers: Dow 8150 (metallocene ethylene octene elastomer) from the United States, SK875L (metallocene ethylene butene elastomer) from South Korea, and ExxonMobil 6202 (metallocene ethylene propylene elastomer) from the United States.

Primary antioxidant, antioxidant 1010, hindered phenol antioxidant, commercially available. Secondary antioxidant, antioxidant 168, phosphite antioxidant, commercially available. Light stabilizer, UV-3808PP5, hindered amine light stabilizer, commercially available. PE wax, AC-6A, commercially available. Toner, commercially available.

Test performance: bending strength is in accordance with ISO178, speed is 2mm/min, impact strength is in accordance with ISO180, gloss is in accordance with GB8807, and the injection molding sample is tested by WGG-20 60 85 triangle gloss meter of Guangzhou Tongfu Electromechanical Equipment Co., Ltd. The gloss of the injection molding sample here is related to the high gloss mold.

The polypropylene material of Example 1-4 has high gloss 83, impact strength>29kJ/m ² , flexural modulus>1000MPa, and adjustable shrinkage, and is very suitable for preparing beach car panels.

Comparative Examples 1 and 2 show that even if other copolymerized types of metallocene elastomers (Dow 8150 metallocene ethylene octene elastomer or Dow SK875L metallocene ethylene butene elastomer) are used instead of the metallocene ethylene propylene elastomer specified in the present invention, the gloss is severely reduced.

Comparative Examples 3 and 4 show that metallocene polyethylene (LLDPE 1018MF) also severely reduces gloss, that is, PE polymerized with a conventional catalyst should be selected.

Comparative Example 5 shows that it is too costly to achieve high impact strength using only elastomer.

Comparative Example 6 shows that using only polyethylene, the impact strength is <20 kJ/m ² .

The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims (9)

1. A high-gloss, high-impact, low-shrinkage, weather-resistant polypropylene, characterized in that its raw materials and the weight percentage of each raw material are as follows: PP homopolymer 36-43%, PP copolymer resin 36-43%, metallocene elastomer 4-8%, PE resin 10-20%, additives and color powder 1-1.5%. 2 . The high-gloss, high-impact, low-shrinkage weather-resistant polypropylene according to claim 1 , characterized in that the PP copolymer resin is a block copolymer resin, with an impact strength of >9 KJ/m ² and a glossiness (60°) of >79. 3. The high gloss, high impact, low shrinkage and weather-resistant polypropylene according to claim 1, characterized in that the metallocene toughening agent is an ethylene propylene elastomer polymerized by a metallocene catalyst. 4. The high-gloss, high-impact, low-shrinkage, weather-resistant polypropylene according to claim 1, characterized in that the PE is PE polymerized by a conventional catalyst and a non-metallocene catalyst. 5. The high-gloss, high-impact, low-shrinkage weather-resistant polypropylene according to claim 1, characterized in that the additives include antioxidant 1010, antioxidant 168, light stabilizer, and lubricant PE wax. 6. The high-gloss, high-impact, low-shrinkage, weather-resistant polypropylene according to claim 1, characterized in that the color powder is a sun-resistant, heat-resistant and weather-resistant color powder. 7. A method for preparing high-gloss, high-impact, low-shrinkage, weather-resistant polypropylene according to any one of claims 1 to 6, characterized in that: the PP resin, toughening agent, additive and color powder are added to a high-speed mixer according to their respective weight percentages and mixed evenly to obtain a mixture, and the mixture is added to a twin-screw extruder for melt extrusion. 8. The method for preparing high-gloss, high-impact, low-shrinkage, weather-resistant polypropylene according to claim 7, characterized in that the extrusion temperature of the twin-screw extruder is 180-200°C, and the screw speed is 300-500 rpm. 9. An application of the high-gloss, high-impact, low-shrinkage, weather-resistant polypropylene according to any one of claims 1 to 6, characterized in that it is used for injection molding of beach car panels of various colors.