WO2023185422A1

WO2023185422A1 - Heat aging-resistant modified polypropylene material, preparation method therefor, and application thereof

Info

Publication number: WO2023185422A1
Application number: PCT/CN2023/080899
Authority: WO
Inventors: 卢先博; 程文超; 陈延安
Original assignee: 上海金发科技发展有限公司; 金发科技股份有限公司
Priority date: 2022-03-28
Filing date: 2023-03-10
Publication date: 2023-10-05
Also published as: CN114672096A; CN114672096B

Abstract

The present invention provides a heat aging-resistant modified polypropylene material, a preparation method therefor, and an application thereof. The heat aging-resistant modified polypropylene material of the present invention comprises the following components in parts by weight: 36.5-96 parts of polypropylene, 0.5-1.5 parts of a stabilizer, 1-40 parts of talcum powder, 3-20 parts of a toughening agent, 0.3-1 part of an antioxidant, and 0-1 part of a processing aid, wherein the stabilizer is a mixture of chitin and α-cyclodextrin. By adding a specific stabilizer, i.e., a mixture of chitin and α-cyclodextrin, into a system, an amide group of the chitin and a hydroxyl group of the α-cyclodextrin introduce a hydrogen bond to a material, thereby improving the aging resistance while meeting basic mechanical properties; and the change of the linear expansion coefficient of the material before and after aging is small, thereby providing a guarantee for the dimensional stability of a product, and not affecting the smell of a material.

Description

A heat-aging-resistant modified polypropylene material and its preparation method and application

Technical field

The invention belongs to the technical field of modified plastics. More specifically, it relates to a heat aging-resistant modified polypropylene material and its preparation method and application.

Background technique

Polypropylene is a common semi-crystalline plastic that has lower rigidity than engineering plastics, so it needs to be modified to meet market demand. Among automotive polypropylene material requirements, heat aging resistance is one of the most common performance requirements. In fact, after long-term thermal aging, the macroscopic properties of the material will often change due to chain movement, chain relaxation, chain breakage, or recrystallization of the material molecules. For example, thermal aging has a certain annealing effect. During aging treatment, the rigidity of the material increases and the toughness decreases. However, the original intention of material design is to maintain the stability and reliability of material performance. For example, Ford Motor Company materials generally require that after thermal aging at 120°C and 1000h according to ISO188, the retention rate of the yield strength and simply supported beam notched impact strength is within -25%-25%. In Volkswagen material certification, it is often required that the performance retention rate before and after material aging (120°C, 500h) is within ±10%. It can be seen that this performance requirement has received widespread attention from mainstream automobile manufacturers.

Therefore, how to ensure that the performance of the material remains basically unchanged before and after aging, or to reduce its change rate, is the technical focus and difficulty in developing heat-aging-resistant modified polypropylene materials. The existing technology mentions a method with high performance retention after high-temperature aging. The core technology is to utilize the synergistic effect of nucleating agents and thioesters. However, thioester small molecules have adverse effects on the material due to the presence of S element. Odor has a great impact, so its application range is subject to certain limitations.

Contents of the invention

In view of the shortcomings of the existing technology, the present invention aims to provide a heat-aging-resistant modified polypropylene material. The heat-aging-resistant modified polypropylene material of the present invention also has excellent heat-aging resistance on the basis of meeting the basic mechanical properties. , the mechanical properties remain stable before and after aging, and the linear expansion coefficient changes little, which ensures the dimensional stability of the product and does not affect the odor of the material.

Another object of the present invention is to provide a method for preparing the heat aging-resistant modified polypropylene material.

Another object of the present invention is to provide the application of the heat aging-resistant modified polypropylene material in the field of automobile manufacturing.

The above objects of the present invention are achieved through the following technical solutions:

The invention first provides a heat aging-resistant modified polypropylene material, which includes the following components by weight:
Polypropylene 36.5~96 parts stabilizer 0.5~1.5 parts talc 1~40 parts toughener 3~20 parts antioxidant 0.3~1 part processing aids 0~1 part

The stabilizer is a mixture of chitin and α-cyclodextrin.

The above-mentioned modified polypropylene material of the present invention is added to the system by adding a specific stabilizer - a mixture of chitin and α-cyclodextrin. The amide group of chitin and the hydroxyl group of α-cyclodextrin introduce hydrogen into the material. The hydrogen bonds greatly improve the heat resistance of the material, can greatly alleviate the performance impact of thermal aging of the material, reduce the performance changes caused by thermal aging, and improve the performance retention rate of the material before and after aging; hydrogen bonding also makes the structure of the material more dense. , so that the linear expansion coefficient changes little before and after aging, ensuring the dimensional stability of the product; and since chitin and α-cyclodextrin are both biomass, there is no impact on the odor of the material. In addition, among the various components of modified polypropylene materials, talc mainly plays the role of improving rigidity; tougheners mainly play the role of improving impact; antioxidants mainly play the role of preventing aging; processing aids are mainly used in extrusion It plays a role in lubrication and dispersion in injection molding.

More preferably, the modified polypropylene material includes the following components by weight:
Polypropylene 47.3~88.5 parts stabilizer 0.8~1.2 parts talc 5~30 parts toughener 5~17 parts antioxidant 0.5~0.8 parts processing aids 0.5~0.8 parts.

Most preferably, the modified polypropylene material includes the following components by weight:
Polypropylene 78 parts stabilizer 1 part talc 20 parts toughener 12 parts
0.6 parts of antioxidants and 0.7 parts of processing aids.

The modified polypropylene material under this ratio has the best mechanical properties and dimensional stability before and after aging.

Preferably, the mass ratio of chitin to α-cyclodextrin is (1-2): (1-2); further, the mass ratio of chitin to α-cyclodextrin is 1:1.

Further, the stabilizer is obtained by grinding chitin and α-cyclodextrin.

Further, the viscosity average molecular weight of the chitin is 5×10 ⁴ to 5×10 ⁵ , more preferably 2×10 ⁵ . The molecular weight of chitin is too high, which can lead to processing difficulties.

Preferably, the melt mass flow rate of the polypropylene under the conditions of 230°C/2.16kg is 1 to 100g/10min. The melt mass flow rate is measured according to the ISO 1133-1:2011 standard method.

Preferably, the mesh number of the talc powder is 3000-5000 mesh.

Preferably, the toughening agent includes one or more of ethylene-octene copolymer, ethylene-butene copolymer, and elastomer.

Preferably, the antioxidant includes one or more of phenolic antioxidants, amine antioxidants, phosphite antioxidants, and hindered phenolic antioxidants.

Further, the phenolic antioxidant includes one or more of antioxidant 1010, antioxidant AO-330, and antioxidant 1790; the amine antioxidant includes erucamide and oleic acid amide. One or more; the phosphite antioxidant includes antioxidant 168, and the hindered phenolic antioxidant includes 3808PP5.

Preferably, the processing aid is a lubricant.

Further, the lubricant is one or more of low molecular esters, metal soaps, stearic acid complex esters, and amines.

Further, the low molecular esters include stearate; the metal soaps include one or more of zinc stearate and calcium stearate; the stearic acid composite esters include tristearic acid. Glyceride; the amines include one or more of erucic acid amide and oleic acid amide.

The invention also provides a preparation method for the above-mentioned modified polypropylene material, which includes the following steps:

Mix polypropylene, stabilizer, talc, toughener, antioxidant and processing aid to obtain a premix. The premix is added to a twin-screw extruder. After melting, mixing and dispersion, it is extruded and granulated to obtain the desired The heat aging resistant modified polypropylene material is described.

Specifically, the above method includes the following steps:

(1) Put polypropylene, stabilizer, talc, toughener, antioxidant and processing aid into high-speed mixing In the mixing machine, mix at a speed of 300-600r/min for 5-10 minutes to obtain a premix;

(2) Add the premix to a twin-screw extruder for melting, mixing and dispersion, extrusion and granulation, and drying below 80°C to obtain the heat-resistant aging modified polypropylene material;

The processing temperatures of each section of the twin-screw extruder are: zone one 150-180°C, zone two 180-200°C, zone three 210-240°C, zone four 230-235°C, zone five 230-235°C, zone six 234~236℃, zone seven is 230~250℃, zone eight is 230~240℃, zone nine is 230~240℃; and the screw speed of the twin-screw extruder is 400~600r/min.

In addition, the application of the above-mentioned modified polypropylene materials in the field of automobile manufacturing is also within the protection scope of the present invention.

Compared with the prior art, the beneficial effects of the present invention are:

The heat-aging-resistant modified polypropylene material prepared by the invention also has excellent heat-aging resistance on the basis of meeting the basic mechanical properties. The mechanical properties remain stable before and after aging, and the linear expansion coefficient changes little, which provides dimensional stability of the product. In order to ensure that the performance retention rate of the material before and after aging is improved, it does not affect the odor of the material.

Detailed ways

The present invention will be further described below with reference to specific embodiments, but the examples do not limit the present invention in any form. Unless otherwise stated, the raw material reagents used in the examples of the present invention are commonly purchased raw material reagents.

1. Raw materials used in the examples and comparative examples:

Chitin-1, viscosity average molecular weight 2×10 ⁴ , brand number C804531, McLean Company;

Chitin-2, viscosity average molecular weight 5×10 ⁴ , brand number C805623, McLean Company;

Chitin-3, viscosity average molecular weight 2×10 ⁵ , brand number C104157, Aladdin Reagent Company;

Chitin-4, viscosity average molecular weight 5×10 ⁵ , brand number C116019, Aladdin Reagent Company;

Chitin-5, viscosity average molecular weight 6×10 ⁵ , brand name KA955, Jiuding Chemical Company;

α-Cyclodextrin, brand number MFCD00078207, McLean;

Polypropylene M2600R, Shanghai Petrochemical, melt mass flow rate at 230℃/2.16kg is 30g/10min;

Polypropylene MH7900, Korean LG Company, melt mass flow rate at 230°C/2.16kg is 150g/10min;

Talc powder, model TYT-777A, 3000 mesh, Tianyuan Company;

Talc powder, model TYT-8875B, 1250 mesh, Tianyuan Company;

Ethylene-butene copolymer, model POE 7467, Dow Chemical;

Toughening agent, propylene-based elastomer, Vistamaxx elastomer 6202, ExxonMobil Company;

Antioxidant 1010, commercially available;

Antioxidant 168, commercially available;

Processing aid: erucamide, commercially available;

Weathering agent: UV-3808PP5, Cytec;

Nucleating agent: HPN-20E, Milliken;

Thioester: Antioxidant 412S, Chemtura.

It should be noted that for commercially available products, the same raw materials used in the following examples and comparative examples are from the same source.

2. Characterization conditions and methods used in the examples and comparative examples:

(1) Tensile strength

The test standard is ISO 527-2-2012, the sample size is 150×10×4mm, and the tensile speed is 50mm/min.

(2)Bending modulus

The test standard is ISO 178-2010, the sample size is 80×10×4mm, the bending speed is 2mm/min, and the span is 64mm.

(3) Izod notch impact strength

Testing standard ISO 180/1eA-2010, sample size is 80×10×4mm.

(4) Odor test

PV3900-2019, specifically 80℃, 2h. The lower the grade, the better the material smell.

(5) The coefficient of linear expansion CLTE is tested in accordance with ISO11359-2, the temperature range is -30~110℃, and the heating rate is 5℃/min.

Change rate % of each performance = (performance before aging - performance after aging) × 100 / performance before aging.

The stabilizer prepared from the mixture of chitin and α-cyclodextrin in the examples and comparative examples is obtained by weighing the chitin and α-cyclodextrin according to the mass ratio and grinding them in an agate mortar for 30 minutes.

Examples 1-16 Preparation of heat aging-resistant modified polypropylene materials with different raw material ratios

1. Table 1 and Table 2 are component lists of 16 heat-aging-resistant modified polypropylene materials provided by the present invention. Among them, Examples 1-16 use chitin with a viscosity average molecular weight of 2×10 ⁵ .

Table 1 Components and dosage of heat aging resistant modified polypropylene materials in Examples 1-9

Table 2 Components and dosage of heat aging resistant modified polypropylene materials in Examples 10-16

2. Preparation method

(1) Put polypropylene, stabilizer, talc powder, toughening agent, antioxidant and processing aid into a high-speed mixer according to the weight parts in Table 1 and Table 2, and mix at a speed of 400r/min for 5 minutes to obtain the preform mixture; mixture

(2) Add the premix to a twin-screw extruder for melting, mixing and dispersion, extrusion and granulation, and drying at 80°C to obtain the heat-resistant aging modified polypropylene material;

The processing temperatures of each section of the twin-screw extruder are: zone one 170°C, zone two 190°C, zone three 230°C, zone four 232°C, zone five 234°C, zone six 236°C, zone seven 240°C, zone eight 240℃, zone nine is 230℃; and the screw speed of the twin-screw extruder is 500r/min.

Example 17 Preparation of a heat-aging-resistant modified polypropylene material

The components and preparation method are the same as those in Example 3, except that the chitin used is chitin with a viscosity average molecular weight of 5×10 ⁴ .

Example 18 Preparation of a heat-aging-resistant modified polypropylene material

The components and preparation method are the same as those in Example 3, except that the chitin used is chitin with a viscosity average molecular weight of 5×10 ⁵ .

Comparative example 1

The components and preparation method are the same as those in Example 3, except that the weight part of the stabilizer is 0.1 part.

Comparative example 2

The components and preparation method are the same as those in Example 3, except that the weight part of the stabilizer is 3 parts.

Comparative example 3

The components and preparation method are the same as those in Example 3, except that no stabilizer is added.

Comparative example 4

The components and preparation method are the same as in Example 3, except that the chitin used is chitin with a viscosity average molecular weight of 2×10 ⁴ .

Comparative example 5

The components and preparation method are the same as those in Example 3, except that the chitin used is chitin with a viscosity average molecular weight of 6×10 ⁵ .

Comparative example 6

The modified polypropylene material components of this comparative example include, in parts by weight: 88.5 parts of copolymerized polypropylene (M2600R), 10 parts of talc powder (TYT-777A), 0.2 parts of nucleating agent (HPN-20E), and 0.4 parts of antioxidant Agent 1010, 0.4 parts of antioxidant 168, 0.2 parts of weathering agent UV-3808PP5, 0.3 parts of thioester (antioxidant 412S), the preparation method is the same as Example 3.

Experimental example

The modified polypropylene materials prepared in Examples 1 to 18 and Comparative Examples 1 to 6 were aged at 150°C for 1000 h, and the tensile strength, flexural modulus, Izod notch impact strength, and linearity of the materials before and after thermal aging were measured respectively. coefficient of expansion and the odor rating of the material.

The test results are shown in Table 3.

table 3

As can be seen from Table 3, after each material passed the 150°C, 1000h aging test, the tensile strength, flexural modulus, and Izod notched impact strength all decreased to varying degrees. The modified polypropylene material prepared in Examples 1 to 18 of the present invention has a tensile strength change rate of -11 to -3.5% and a flexural modulus change rate of -12.5 to -2.2% before and after aging at 150°C for 1000 hours. , the change rate of Izod notched impact strength is -13.5~-5.5%, the change rate of CLTE (flow direction) before and after thermal aging is -15.9~-4%, and the odor level of the material is 3.5.

As can be seen from the test results of Comparative Examples 1 to 5, the change rate of tensile strength is -24~-12.1%, the change rate of flexural modulus is -23~-10%, and the change rate of Izod notched impact strength is -30.6~ -22%, the CLTE (flow direction) change rate before and after thermal aging is -17.8~-10.7%, and the performance retention before and after aging is poor.

Comparative Example 6 adopts the solution of thioester and nucleating agent. The change rate of tensile strength is -36%, the change rate of flexural modulus is -11.5%, and the change rate of Izod notched impact strength is -25%. The results before and after thermal aging are The CLTE (direction of flow) change rate was -13.2%, and the material had an odor rating of 4.0 after heat aging. Although individual test items, such as the change rate of flexural modulus and the change rate of CLTE, are smaller, the overall effect is still worse than that of the modified polypropylene materials of Examples 1 to 16, and the material smell is worse.

Obviously, the above-mentioned embodiments of the present invention are only examples to clearly illustrate the present invention, and are not intended to limit the implementation of the present invention. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. An exhaustive list of all implementations is not necessary or possible. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention shall be included in the protection scope of the claims of the present invention.

Claims

A heat aging-resistant modified polypropylene material, which is characterized in that it includes the following components by weight:
Polypropylene 36.5~96 parts stabilizer 0.5~1.5 parts talc 1~40 parts toughener 3~20 parts antioxidant 0.3~1 part processing aids 0~1 part

The stabilizer is a mixture of chitin and α-cyclodextrin.
The heat aging resistant modified polypropylene material according to claim 1, characterized in that it includes the following components by weight:
Polypropylene 47.3~88.5 parts stabilizer 0.8~1.2 parts talc 5~30 parts toughener 5~17 parts antioxidant 0.5~0.8 parts processing aids 0.5~0.8 parts.
The heat aging-resistant modified polypropylene material according to claim 1 or 2, characterized in that the mass ratio of chitin to α-cyclodextrin is (1-2): (1-2).
The heat aging-resistant modified polypropylene material according to claim 1 or 2, characterized in that the viscosity average molecular weight of the chitin is 5×10 4 to 5×10 5 .
The heat-aging-resistant modified polypropylene material according to claim 1, characterized in that the melt mass flow rate of the polypropylene under the condition of 230°C/2.16kg is 1 to 100g/10min.
The heat aging resistant modified polypropylene material according to claim 1, characterized in that the toughening agent includes one or more of ethylene-octene copolymer and ethylene-butene copolymer.
The heat-aging-resistant modified polypropylene material according to claim 1, characterized in that the antioxidants include phenolic antioxidants, amine antioxidants, phosphite antioxidants, and hindered phenolic antioxidants. one or more of the agents.
The heat aging resistant modified polypropylene material according to claim 1, characterized in that the processing aid is a lubricant.
The preparation method of heat-aging-resistant modified polypropylene material according to any one of claims 1 to 8, characterized in that it includes the following steps:

Mix polypropylene, stabilizer, talc, toughener, antioxidant and processing aid to obtain a premix. The premix is added to a twin-screw extruder. After melting, mixing and dispersion, it is extruded and granulated to obtain the desired The heat aging resistant modified polypropylene material is described.
Application of the heat-aging-resistant modified polypropylene material according to any one of claims 1 to 8 in the field of automobile manufacturing.