阅读说明：本技术 一种抗热变形、低热收缩、耐冲击聚丙烯复合材料及其制备方法 (Heat deformation resistant, low heat shrinkage and impact resistant polypropylene composite material and preparation method thereof ) 是由 冯杨 张锴 徐美玲 张千惠 蔡青 周文 于 2020-12-15 设计创作，主要内容包括：本发明公开了一种抗热变形、低热收缩、耐冲击聚丙烯复合材料及其制备方法。该种聚丙烯复合材料由以下重量百分比的原料组成：聚丙烯45-90％；β晶成核剂0.1-5％；无机填料5-30％；弹性体增韧剂5-20％；抗刮擦助剂0.5-3％；稳定剂0.1-2％；其他添加剂0-5％。通过引入β晶成核剂可以诱导聚丙烯β晶的形成,该晶型有利于提升材料的热变形温度及韧性,并能在一定温度范围抑制α晶的形成以减少材料经热处理后的收缩。通过β晶成核剂、无机填料的协同作用,聚丙烯材料可以在相对更高的温度下不发生明显变形；在注塑成型后可以有相对更低的收缩率,且即使再经高温处理也会有更小的二次收缩幅度,即具有更好的尺寸稳定性。β晶成核剂和弹性体增韧剂的协同则提升了材料的抗冲击性能。(The invention discloses a polypropylene composite material with heat deformation resistance, low thermal shrinkage and impact resistance and a preparation method thereof. The polypropylene composite material is composed of the following raw materials in percentage by weight: 45-90% of polypropylene; 0.1 to 5 percent of beta crystal nucleating agent; 5-30% of inorganic filler; 5-20% of an elastomer toughening agent; 0.5-3% of anti-scratch auxiliary agent; 0.1 to 2 percent of stabilizer; 0-5% of other additives. The beta crystal nucleating agent is introduced to induce the formation of polypropylene beta crystal, the crystal is beneficial to improving the thermal deformation temperature and toughness of the material, and the formation of alpha crystal can be inhibited in a certain temperature range to reduce the shrinkage of the material after heat treatment. By the synergistic effect of the beta crystal nucleating agent and the inorganic filler, the polypropylene material can not deform obviously at a relatively higher temperature; after injection molding, the shrinkage rate can be relatively lower, and even after high-temperature treatment, the secondary shrinkage amplitude is smaller, namely, the dimensional stability is better. The beta crystal nucleating agent and the elastomer toughening agent cooperate to improve the impact resistance of the material.)

1. A polypropylene composite material with heat deformation resistance, low heat shrinkage and impact resistance is characterized in that: the composite material consists of the following raw materials in percentage by weight: 45-90% of polypropylene; 0.1 to 5 percent of beta crystal nucleating agent; 5-30% of inorganic filler; 5-20% of an elastomer toughening agent; 0.5-3% of anti-scratch auxiliary agent; 0.1 to 2 percent of stabilizer; 0-5% of other additives.

2. The heat distortion resistant, low thermal shrinkage, impact resistant polypropylene composite of claim 1, wherein: the polypropylene is homopolymerized or copolymerized polypropylene with melt flow rate of 10-90g/10min, the comonomer of the copolymerized polypropylene is ethylene, and the molar content of ethylene repeating units is 4-10%.

3. The heat distortion resistant, low thermal shrinkage, impact resistant polypropylene composite of claim 1, wherein: the beta crystal nucleating agent is one or a combination of a fused ring compound with a quasi-planar structure, aromatic amines, a compound of IIA metal salt and dicarboxylic acid and rare earth compounds.

4. The heat distortion resistant, low thermal shrinkage, impact resistant polypropylene composite of claim 1, wherein: the inorganic filler is talcum powder with the average size of 1-10 mu m.

5. The heat distortion resistant, low thermal shrinkage, impact resistant polypropylene composite of claim 1, wherein: the toughening agent is ethylene-octene copolymer or ethylene-butene copolymer or a combination of both, having a density of 0.88-0.91g/cm³The melt flow rate is 0.5-10g/10 min.

6. The heat distortion resistant, low thermal shrinkage, impact resistant polypropylene composite of claim 1, wherein: the anti-scratch auxiliary agent is any one or a combination of more of erucamide, stearyl erucamide, oleamide, behenamide, silicone and the like.

7. The heat distortion resistant, low thermal shrinkage, impact resistant polypropylene composite of claim 1, wherein: the stabilizer is a main antioxidant and a secondary antioxidant which are considered to be required by a person skilled in the art, wherein the main antioxidant is a hindered phenol or thioester antioxidant, and the secondary antioxidant is a phosphite or lipid antioxidant.

8. The heat distortion resistant, low thermal shrinkage, impact resistant polypropylene composite of claim 1, wherein: the other additives are one or a combination of several of antioxidant, flame retardant, foaming agent, colorant, color master batch, antistatic auxiliary agent, surfactant, plasticizer, coupling agent and antimicrobial auxiliary agent which are considered to be needed by the people in the field.

9. The method for preparing a heat distortion resistant, low heat shrinkage, impact resistant polypropylene composite according to any one of claims 1 to 8, wherein: the method comprises the following specific steps:

(1) dry-mixing polypropylene, a beta crystal nucleating agent, an inorganic filler, a toughening agent, an anti-scratch auxiliary agent, a stabilizer and other additives in a high-speed mixer for 8-15min according to the proportion to obtain a premix;

(2) adding the premix obtained in the previous step into a double-screw extruder from a main screw feeding port, and cooling and granulating after melt extrusion, wherein the process comprises the following steps: the first zone 190-; the retention time is 1-2min, and the pressure is 12-18 MPa.

Technical Field

The invention relates to a polypropylene composite material and a preparation method thereof, and the obtained material has the characteristics of heat deformation resistance, low thermal shrinkage, impact resistance and the like, and belongs to the technical field of processing and modification of high polymer materials.

Background

Polypropylene is a common thermoplastic polymer and also an important automotive material, and is currently used in a large amount for automotive interior and exterior trim. Since pure polypropylene generally cannot meet the performance requirements of automotive materials, it needs to be modified and finally put into use in the form of polypropylene composite materials. For the polypropylene composite material for vehicles, polypropylene, inorganic filler and toughening agent are three most basic and key components, and the three determine the mechanical property, dimensional stability, melt flow capacity and the like of the material. Therefore, the regulation and control of the polypropylene composite material are mainly realized by adjusting the types and (or) the mixture ratio of the three components.

Polypropylene is a semicrystalline polymer whose crystallization behavior has a significant impact on performance. The change of the crystallization behavior of the material is also involved to a certain extent by adjusting the types and/or the proportions of the polypropylene, the inorganic filler and the toughening agent, and particularly the inorganic filler (such as talcum powder) can play a role in inducing the formation of polypropylene alpha crystals. Nucleating agents are important factors influencing material crystallization behaviors, however, almost all researches and reports about polypropylene nucleating agents to date aim at pure polypropylene systems, and the performance regulation of the nucleating agents applied to polypropylene composite material systems is rare.

The invention introduces the high-efficiency polypropylene beta-crystal nucleating agent into a polypropylene composite material (polypropylene/inorganic filler/toughening agent) system: the formation of polypropylene beta crystals can be promoted by introducing the beta crystal nucleating agent, the crystal form is favorable for improving the thermal deformation temperature and the impact resistance of the material, and can inhibit the formation of alpha crystals within a certain temperature range, so that the shrinkage of the material after heat treatment is reduced; the introduction of the inorganic filler can enhance the rigidity and the dimensional stability of the material; through the synergistic effect of the beta-crystal nucleating agent and the inorganic filler, the composite material can not deform obviously at a relatively higher temperature, in addition, the shrinkage rate after injection molding can be relatively lower, and even if the composite material is subjected to high-temperature treatment, the composite material has smaller secondary shrinkage amplitude, namely, the composite material has better dimensional stability; the beta crystal nucleating agent and the elastomer toughening agent cooperate to further improve the impact resistance of the material.

Disclosure of Invention

The invention aims to develop a polypropylene composite material with heat deformation resistance, low heat shrinkage and impact resistance, and the obtained material can be used for injection molding of parts of automobiles and other products.

The invention also aims to provide a preparation method of the polypropylene composite material.

In order to achieve the purpose, the invention adopts the following technical scheme:

a polypropylene composite material with heat deformation resistance, low thermal shrinkage and impact resistance is prepared from the following raw materials in percentage by weight: 45-90% of polypropylene; 0.1 to 5 percent of beta crystal nucleating agent; 5-30% of inorganic filler; 5-20% of an elastomer toughening agent; 0.5-3% of anti-scratch auxiliary agent; 0.1 to 2 percent of stabilizer; 0-5% of other additives.

Wherein the content of the first and second substances,

the polypropylene is homopolymerized or copolymerized polypropylene with melt flow rate of 10-90g/10min, the comonomer of the copolymerized polypropylene is ethylene, and the molar content of ethylene repeating units is 4-10%.

The beta crystal nucleating agent is one or a combination of a fused ring compound with a quasi-planar structure, aromatic amines, a compound of IIA metal salt and dicarboxylic acid and rare earth compounds.

The inorganic filler is talcum powder with the average size of 1-10 mu m.

The toughening agent is ethylene-octene copolymer or ethylene-butene copolymer or the combination of the two, and the density is 0.88-0.91g/cm³The melt flow rate is 0.5-10g/10 min.

The anti-scratch auxiliary agent is any one or a combination of more of erucamide, stearyl erucamide, oleamide, behenamide, silicone and the like.

The stabilizer is a main antioxidant and a secondary antioxidant which are considered to be required by a person skilled in the art, wherein the main antioxidant is a hindered phenol or thioester antioxidant, and the secondary antioxidant is a phosphite or lipid antioxidant.

The other additives are one or a combination of several of antioxidant, flame retardant, foaming agent, colorant, color master batch, antistatic auxiliary agent, surfactant, plasticizer, coupling agent and antimicrobial auxiliary agent which are considered to be needed by the people in the field.

The preparation method of the polypropylene composite material with heat deformation resistance, low heat shrinkage and impact resistance comprises the following specific steps:

(1) and dry-mixing the polypropylene, the beta-crystal nucleating agent, the inorganic filler, the toughening agent, the anti-scratch auxiliary agent, the stabilizer and other additives in a high-speed mixer for 8-15min according to the proportion to obtain the premix.

(2) Adding the premix obtained in the previous step into a double-screw extruder from a main screw feeding port, and cooling and granulating after melt extrusion, wherein the process comprises the following steps: the first zone 190-; the retention time is 1-2min, and the pressure is 12-18 MPa.

The invention has the advantages that:

1. the beta crystal nucleating agent can promote the formation of polypropylene beta crystal, the crystal form is favorable for improving the heat distortion temperature and the shock resistance of the material, and can inhibit the formation of alpha crystal within a certain temperature range, thereby reducing the shrinkage of the material after heat treatment.

2. The inorganic filler may enhance the rigidity and dimensional stability of the material.

3. Through the synergistic effect of the beta crystal nucleating agent and the inorganic filler, the thermal deformation temperature of the composite material is improved, in addition, the shrinkage rate after injection molding can be relatively lower, and smaller secondary shrinkage amplitude can be realized even after high-temperature treatment.

4. The beta crystal nucleating agent and the elastomer toughening agent cooperate to further improve the impact resistance of the material.

Detailed Description

The present invention is further illustrated by the following examples and comparative examples, which are not intended to limit the scope of the invention.

In the composite formulations of the examples and comparative examples, the polypropylene used was a block copolymer polypropylene having a melt flow rate of about 32g/10 min.

The polypropylene beta-crystal nucleating agent is a rare earth compound nucleating agent of Winner company.

The inorganic filler is talcum powder with the average grain diameter of 10 mu m.

The toughening agent used was ethylene-octene copolymer 8150 from DOW corporation.

The scratch-resistant aid used is silicone.

The stabilizers used were Negonox DSTP (chemical name: stearyl thiodipropionate) from ICE of the United kingdom, Irganox 1010 (chemical name: pentaerythritol tetrakis (3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate) from Ciba, and Irgafos168 (chemical name: tris (2, 4-di-tert-butylphenyl) phosphite) from Ciba.

Example 1

(1) Weighing 61.4% of polypropylene, 0.1% of beta-crystal nucleating agent, 20% of talcum powder, 15% of elastomer toughening agent, 2% of scratch-resistant auxiliary agent, 0.3% of Negonox DSTP, 0.1% of Irganox 10100.1%, Irgafos 1680.1% and 1% of toner in percentage by weight, and dry-mixing in a high-speed mixer for 8min to obtain the premix.

(2) Adding the premix into a double-screw extruder from a main screw feeding port, performing melt extrusion, cooling and granulating, wherein the process comprises the following steps: the first zone 190-; the retention time is 1-2min, and the pressure is 12-18 MPa.

Example 2

(1) Weighing 61.2% of polypropylene, 0.3% of beta-crystal nucleating agent, 20% of talcum powder, 15% of elastomer toughening agent, 2% of scratch-resistant auxiliary agent, 0.3% of Negonox DSTP, 0.3% of Irganox 10100.1%, Irgafos 1680.1% and 1% of toner in percentage by weight, and dry-mixing in a high-speed mixer for 8min to obtain the premix.

(2) Adding the premix into a double-screw extruder from a main screw feeding port, performing melt extrusion, cooling and granulating, wherein the process comprises the following steps: the first zone 190-; the retention time is 1-2min, and the pressure is 12-18 MPa.

Example 3

(1) Weighing 61% of polypropylene, 0.5% of beta-crystal nucleating agent, 20% of talcum powder, 15% of elastomer toughening agent, 2% of scratch-resistant auxiliary agent, 0.3% of Negonox DSTP, 0.1% of Irganox 10100.1%, 0.1% of Irgafos 168and 1% of toner in percentage by weight, and dry-mixing in a high-speed mixer for 8min to obtain the premix.

(2) Adding the premix into a double-screw extruder from a main screw feeding port, performing melt extrusion, cooling and granulating, wherein the process comprises the following steps: the first zone 190-; the retention time is 1-2min, and the pressure is 12-18 MPa.

Example 4

(1) Weighing 60.8% of polypropylene, 0.7% of beta-crystal nucleating agent, 20% of talcum powder, 15% of elastomer toughening agent, 2% of scratch-resistant auxiliary agent, 0.3% of Negonox DSTP, 0.1% of Irganox 10100.1%, Irgafos 1680.1% and 1% of toner in percentage by weight, and dry-mixing in a high-speed mixer for 8min to obtain the premix.

(2) Adding the premix into a double-screw extruder from a main screw feeding port, performing melt extrusion, cooling and granulating, wherein the process comprises the following steps: the first zone 190-; the retention time is 1-2min, and the pressure is 12-18 MPa.

Example 5

(1) Weighing 70.8% of polypropylene, 0.7% of beta-crystal nucleating agent, 10% of talcum powder, 15% of elastomer toughening agent, 2% of scratch-resistant auxiliary agent, 0.3% of Negonox DSTP, 0.1% of Irganox 10100.1%, Irgafos 1680.1% and 1% of toner in percentage by weight, and dry-mixing in a high-speed mixer for 8min to obtain the premix.

(2) Adding the premix into a double-screw extruder from a main screw feeding port, performing melt extrusion, cooling and granulating, wherein the process comprises the following steps: the first zone 190-; the retention time is 1-2min, and the pressure is 12-18 MPa.

Comparative example

(1) Weighing 61.5% of polypropylene, 20% of talcum powder, 15% of elastomer toughening agent, 2% of scratch-resistant auxiliary agent, 0.3% of Negonox DSTP, Irganox 10100.1%, Irgafos 1680.1% and 1% of toner according to weight percentage, and dry-mixing for 8min in a high-speed mixer to obtain a premix.

(2) Adding the premix into a double-screw extruder from a main screw feeding port, performing melt extrusion, cooling and granulating, wherein the process comprises the following steps: the first zone 190-; the retention time is 1-2min, and the pressure is 12-18 MPa.

Performance evaluation method:

the sample density was performed according to ISO 1183-1 standard; the melt flow rate is carried out according to ISO 1133-1; the tensile property test is carried out according to the ISO 527-2 standard, and the size of a test sample is 170mm multiplied by 10mm multiplied by 4 mm; the impact test of the simple beam notch is carried out according to the ISO 179-1 standard, the size of a sample is 80mm multiplied by 10mm multiplied by 4mm, and the depth of the notch is one third of the thickness of the sample; the heat distortion temperature test is carried out according to ISO 75-2, and the size of a test sample is 120mm multiplied by 10mm multiplied by 4 mm; the shrinkage test sample size is 356mm multiplied by 70mm multiplied by 3.2mm, the shrinkage test after injection molding is carried out after the sample is subjected to injection molding and is placed at room temperature for 24h, the sample plate is placed in an environment at 110 ℃ for annealing for 24h after the test is finished, and then the shrinkage test after annealing is carried out.

The weight percentages of the main components of each example and comparative example are shown in table 1, and the corresponding performance test results are shown in table 2.

TABLE 1 EXAMPLES 1-5 AND COMPARATIVE EXAMPLE MATERIALS COMPOSITION (in weight percent)

TABLE 2 results of Performance testing of examples 1-7 and comparative materials

As can be seen from the performance test results of the materials of the comparative example and the examples 1 to 4, the introduction of the beta-crystal nucleating agent in the composite material can improve the impact resistance and the heat distortion temperature of the material, and the improvement is more obvious along with the increase of the content of the nucleating agent. In addition, the introduction of the beta-crystal nucleating agent also enables the material to have lower shrinkage after injection molding compared with that without the addition of the nucleating agent, and the material also has smaller secondary shrinkage after heat treatment, namely the material has relatively better dimensional stability. The results of comparative examples 4 and 5 show that the increase of the content of the talcum powder is also beneficial to reducing the shrinkage rate of the material, and the synergistic effect of the beta-crystal nucleating agent and the talcum powder can enable the material to have higher dimensional stability, heat deformation resistance and impact resistance.

The above description is only for the specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope defined by the claims.