A polypropylene composition, its preparation method and application

Abstract

The present invention belongs to the field of polypropylene materials, and specifically discloses a polypropylene composition, a preparation method thereof, and an application. In the polypropylene composition of the present invention, the boronized tungsten and potassium bicarbonate composite adsorbent can significantly reduce the odor and VOC of the polypropylene composition, realizing the characteristics that the polypropylene material has excellent mechanical properties, a low odor level, and low VOC at the same time.

Description

Technical Field

[0001] The present invention belongs to the field of polypropylene materials, and particularly relates to a polypropylene composition, a preparation method thereof and an application thereof. Background Art

[0002] Due to advantages such as low cost, light weight, good chemical resistance, excellent processing performance, and easy recyclability, polypropylene materials are widely used in the automotive and household appliance industries, especially in automotive interior and exterior parts, such as door interior panels, instrument panels, pillars, seat guards, bumpers, side enclosures, deflectors, fenders, etc. With the increasing development of the automotive industry and the continuous enhancement of consumers' awareness of environmental protection and health, people not only require cars to have a spacious interior space, a wide field of vision and comfortable seating, but also require fresh and good-quality air inside the car. Volatile harmful substances inside the car have attracted people's attention, and their intuitive reflection is the perception of smell. Research shows that the sources of car smell are diverse, and volatile organic compounds (VOCs for short) from interior parts are one of the main reasons affecting the air quality inside the car. Most interior parts contain a certain amount of volatile organic compounds, which are mainly substances such as alkanes, alkenes, aromatics, amines, phenols, thiols, peroxides, aldehydes, and ketones. The boiling points of these substances are usually in the range of 50 - 260°C. When the temperature reaches a certain level, under the action of light and heat, unpleasant smells are produced, and even cause discomfort reactions such as headaches, dry coughs, and allergies. On March 1, 2012, GB / T27630 - 2011 "Evaluation Guide for Air Quality in Passenger Cars" began to be implemented, which put forward the limit requirements for 8 substances such as benzene and aldehydes in the air of the whole vehicle compartment.

[0003] Automotive interior parts are one of the main air pollution sources inside the car, and polypropylene materials are one of the main materials for manufacturing automotive interior parts. Therefore, preparing polypropylene materials with low odor and low volatile organic compounds (8 substances such as benzene and aldehydes) has become a new hot spot in modified plastics. To overcome these problems, plastic resin producers have long been committed to reducing the emission level of these odors by adding adsorbents and achieved certain results. Currently, materials used as volatile adsorbents include activated carbon, molecular sieves, porous silica gels, etc. However, the adsorption saturation values of these adsorption materials are relatively low, and small molecules still remain in the interior parts, failing to achieve the purpose of complete eradication.

[0004] The full name of PCR is Post-Consumer Recycled material, that is, recycled material, usually referring to recycled materials such as PET, PP, HDPE, etc., and then reprocessed into plastic raw materials for manufacturing new molding materials. Using this PCR material as a recycled material in polypropylene materials conforms to the development trend of reducing carbon emissions and being environmentally friendly. However, as is well known, when conventional PCR materials are used as recycled materials, their odor emission performance, like that of conventional plastics, still cannot meet the VOC emission requirements for automotive interiors. How to achieve both mechanical properties and low odor levels and low VOCs when using PCR materials as raw materials for automotive interiors is one of the key research points currently. Summary of the Invention

[0005] Aiming at the problem in the above-mentioned prior art that when preparing raw materials for automotive interiors, it is impossible to balance mechanical properties, low odor levels, and low VOCs, the present invention provides a polypropylene composition, its preparation method, and applications.

[0006] To achieve the above objectives, the specific technical solutions include the following:

[0007] A polypropylene composition, comprising the following components in parts by weight: 66 - 137 parts of polypropylene, 0 - 31 parts of filler, 4 - 23 parts of toughening agent, 0.2 - 2.7 parts of adsorbent, 0.09 - 2.2 parts of auxiliary agent; the adsorbent comprises 0.08 - 1.2 parts by weight of tungsten boride and 0.15 - 1.5 parts by weight of potassium bicarbonate.

[0008] The polypropylene composition of the present invention contains tungsten boride and potassium bicarbonate adsorbents. Tungsten boride has strong polarity and can adsorb polar small molecule substances, while the carbon dioxide generated by the thermal decomposition of potassium bicarbonate can dissolve and carry away non-polar small molecule substances. Therefore, the composite adsorbent of tungsten boride and potassium bicarbonate can significantly reduce the odor and VOC of the polypropylene composition, achieving the characteristics that the polypropylene material has excellent mechanical properties, low odor levels, and low VOCs at the same time.

[0009] Preferably, 70 - 135 parts of polypropylene, 0 - 30 parts of filler, 5 - 20 parts of toughening agent, 0.3 - 2.5 parts of adsorbent, 0.1 - 2 parts of auxiliary agent; the adsorbent comprises 0.1 - 1 part by weight of tungsten boride and 0.2 - 1.5 parts by weight of potassium bicarbonate.

[0010] In the polypropylene composition, the mass percentage content of the polypropylene is not less than 40%, preferably the mass percentage content of the polypropylene is not less than 50%.

[0011] Preferably, the polypropylene has a melt mass flow rate of 10 - 100 g / 10 min at a test temperature of 230 °C and a load of 2.16 kg according to ISO 1133 - 2012. Further preferably, it is 30 - 60 g / 10 min.

[0012] If the melt mass flow rate is too low, the product forming difficulty increases. If the melt mass flow rate is too high, there are many small molecules, which have a negative impact on the VOC of the material. Therefore, selecting the above melt mass flow rate is beneficial to the forming of the polypropylene composition and reducing the influence of VOC.

[0013] Preferably, the polypropylene includes PCR polypropylene, and the mass percentage of the PCR polypropylene in the polypropylene is 20 - 50%. Then, the mass percentage of the PCR polypropylene in the polypropylene can be 20%, 25%, 30%, 35%, 40%, 45%, 50%, etc., as well as specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the above range. At the above mass percentage of the PCR polypropylene in the polypropylene, the comprehensive properties of the overall polypropylene composition in terms of mechanical properties, odor and VOC are better.

[0014] There is no special requirement for the melt mass flow rate of the PCR polypropylene. The PCR polypropylene commonly used in the art can be selected. For example, the melt mass flow rate at a test temperature of 230 °C and a load of 2.16 kg according to ISO 1133 - 2012 can be 1 - 100 g / 10 min, or 20 - 40 g / 10 min can also be selected.

[0015] When the polypropylene includes PCR polypropylene, the PCR polypropylene also undergoes pretreatment, and the pretreatment includes the following steps: subjecting the PCR polypropylene to boiling water treatment and drying treatment in sequence to obtain the pretreated PCR polypropylene.

[0016] Preferably, the temperature of the boiling water treatment is 95 - 110 °C, the time of the boiling water treatment is 5 - 24 h, the temperature of the drying treatment is 100 - 130 °C, and the time of the drying treatment is 6 - 12 h.

[0017] The weight part of tungsten boride can be 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, etc., as well as specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the above range.

[0018] The parts by weight of potassium bicarbonate can be 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, etc., as well as specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the above range.

[0019] Preferably, the mass ratio of tungsten boride to potassium bicarbonate is 1:(0.5 - 6.5). More preferably, the mass ratio of tungsten boride to potassium bicarbonate is 1:(1 - 3). Then, the mass ratio of tungsten boride to potassium bicarbonate can be (1:0.5), (1:1), (1:1.5), (1:2), (1:2.5), (1:3), (1:3.5), (1:4), (1:4.5), (1:5), (1:5.5), (1:6), (1:6.5), as well as specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the above range.

[0020] The inventors found that when the dosages within the above mass ratio range of tungsten boride and potassium bicarbonate are selected, the odor, VOC, and mechanical properties of the polypropylene composition are better.

[0021] Preferably, the filler includes at least one of talcum powder, calcium carbonate, and basic magnesium sulfate whiskers.

[0022] Preferably, the toughening agent includes at least one of ethylene-octene random copolymer, ethylene-butene random copolymer, metallocene linear low-density polyethylene, metallocene ethylene-propylene copolymer, and hydrogenated styrene-butadiene-styrene linear triblock copolymer.

[0023] Preferably, the auxiliary agent includes the following components in parts by weight: 0.2 - 0.5 parts of scratch-resistant agent, 0.1 - 0.4 parts of lubricant, and 0.1 - 0.4 parts of antioxidant.

[0024] Preferably, the scratch-resistant agent includes at least one of amide-based and silicone-based scratch-resistant agents; the lubricant includes stearate-based lubricants, and the antioxidant includes hindered phenol antioxidants and phosphite antioxidants.

[0025] More preferably, the parts by weight of the hindered phenol antioxidant are 0.05 - 0.2 parts, and the parts by weight of the phosphite antioxidant are 0.05 - 0.2 parts.

[0026] The present invention also provides a preparation method of the above polypropylene composition, including the following steps:

[0027] Mixing each raw material component in sequence, followed by melt extrusion, granulation, and drying to obtain the polypropylene composition.

[0028] Preferably, the temperature of the melt extrusion is 170 - 220 °C.

[0029] Preferably, the temperature of the drying is 100 - 130 °C, and the time of the drying is 3 - 48 h.

[0030] The present invention also provides an application of the polypropylene composition in automotive interiors. The polypropylene composition of the present invention has excellent mechanical properties, low odor, and low VOC, meeting the application requirements of automotive interiors.

[0031] Compared with the prior art, the present invention has the following beneficial effects: In the polypropylene composition of the present invention, the boronized tungsten and potassium bicarbonate composite adsorbent can significantly reduce the odor and VOC of the polypropylene composition, making the polypropylene material have the characteristics of excellent mechanical properties, low odor level, and low VOC. Detailed Embodiments

[0032] To better illustrate the purpose, technical solution, and advantages of the present invention, the present invention will be further described below through specific embodiments. The test methods used in the embodiments and / or comparative examples are all conventional methods unless otherwise specified; the materials, reagents, etc. used are all commercially available unless otherwise specified.

[0033] The main representative materials used in the embodiments and comparative examples are as follows:

[0034] Polypropylene PP:

[0035] PP - 1: EP300M (copolymer, MFR = 10 g / 10 min), CNOOC and Shell;

[0036] PP - 2: EP548R (copolymer, MFR = 30 g / 10 min), CNOOC and Shell;

[0037] PP - 3: BX3900 (copolymer, MFR = 60 g / 10 min), SK;

[0038] PP - 4: BX3920 (copolymer, MFR = 100 g / 10 min), SK;

[0039] PCR polypropylene: PP - KF027 (copolymer, MFR = 30 g / 10 min), prepared by the following method: (1) Collect the broken materials of the washing machine inner barrel from the market; (2) Conduct the first - stage cleaning with boiling water at 100 °C; then conduct the second - stage cleaning with boiling water at 100 °C; then conduct rinsing, centrifuging, and dehydration; (3) Conduct color sorting (removing the miscellaneous colors with L value < 75) after dehydration; (4) Then granulate the color - sorted particles through a single - screw extruder to finally obtain PP - KF027 particles.

[0040] The above MFR values were all melt mass flow rates measured according to ISO1133-2012 at a test temperature of 230 °C and a load of 2.16 kg.

[0041] Filler: Talc powder, AH-51210 (3000-mesh talc powder), Aihai, Liaoning

[0042] Toughening agent: Ethylene-octene random copolymer, 8842, Dow Chemical, USA

[0043] Scratch resistance agent: Amide type, Erucamide, Shanghai Kayin Chemical Industry

[0044] Adsorbent: Molecular sieve: 13X molecular sieve, Jiangsu Xianfeng Nano Materials Technology Co., Ltd.

[0045] Tungsten boride: WB2, Jinzhou Haixin Metal Materials; Potassium bicarbonate: KHCO3, Kunshan Sheng'an Biotechnology Co., Ltd.

[0046] Antioxidant 1: Pentaerythritol tetrakis [β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate], SONOX 1010, Shandong Sanfeng

[0047] Antioxidant 2: Tris (2,4-di-tert-butylphenyl) phosphite, SONOX 168, Shandong Sanfeng

[0048] Lubricant: Zinc stearate, BS-2818, Huamingtai Chemical Industry

[0049] Examples 1-12 and Comparative Examples 1-4

[0050] A method for preparing a polypropylene composition, comprising the following steps:

[0051] (1) Subject PCR polypropylene to cooking in water at 100 °C for 8 h, and then vacuum drying at 120 °C for 8 h to obtain pretreated PCR polypropylene.

[0052] (2) According to the formulations in Tables 2 and 3, the PCRPP pretreated in step (1) or the PCR polypropylene not pretreated in step (1), polypropylene, filler, toughening agent, adsorbent, and additives are mixed in a high-speed mixer at a rotation speed of 500 - 800 revolutions per minute for 3 - 5 minutes; the above mixed particles are added to a 75D co-rotating twin-screw extruder for melt extrusion, pelletizing, in-line drying, cooling, off-line drying, and packaging in sequence to obtain the polypropylene composition, wherein the temperature of the twin-screw extruder from the feeding section to the head is 170 °C, 200 °C, 200 °C, 210 °C, 210 °C, 205 °C, 205 °C, 205 °C, 200 °C, 200 °C in sequence, the in-line drying conditions are 100 - 130 °C, 3 - 8 h, and the off-line drying conditions are 100 - 130 °C, 12 - 24 h.

[0053] Performance test:

[0054] (1) Izod impact strength of cantilever beam: Tested according to the ISO 180-2000 standard, and the notch type A notch is selected.

[0055] (2) Organic volatile compounds are tested for the total carbon content (TVOC) according to the PV3341 "Emission of Organic Compounds" standard of Shanghai Volkswagen, and the unit is μgC / g.

[0056] (3) The odor performance of the polypropylene compositions of the examples and comparative examples is tested according to the PV3900 "Odor Experiment of Parts in Automobile Compartments" standard of Shanghai Volkswagen: First, 20 g of the granulated polypropylene composition is placed in a 1 L odor test bottle; then it is placed in an oven at 80 °C for 2 h. After taking it out and waiting for the bottle to cool to 60 °C, the odor grades of the granulated polypropylene compositions of each example and comparative example are evaluated according to the odor grade standard in Table 1. The number of evaluators is 5, and the average value of the grades is calculated. The smaller the average value, the lower the odor of the product.

[0057] Table 1

[0058] grade Odor description 1 Can't feel 2 Feel it, not disturbing 3 Noticeable but not intrusive 4 Disturb 5 Strong dislike 6 Intolerable

[0059] Table 1

[0060]

[0061]

[0062] Table 2

[0063] Components Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 PP-3 75 75 75 75 Step (1) PCRPP after pretreatment 22 22 22 22 filler 25 25 25 25 Toughening agent 10 10 10 10 Scratch resistant agent 0.5 0.5 0.5 0.5 Tungsten Diboride - - 1.5 - Potassium bicarbonate - 1.5 - - Molecular sieve - - - 1.5 Antioxidant 1 0.2 0.2 0.2 0.2 Antioxidant 2 0.2 0.2 0.2 0.2 Lubricants 0.4 0.4 0.4 0.4 performance Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Odor / Grade 3.8 3.6 3.7 3.6 TVOC(<C16) / (μgC / g) 28.2 26.8 27.7 19.8 <![CDATA[Izod impact strength of cantilever beam / (KJ / m 2 )]]> 22.5 20.9 22.6 21.7

[0064] As can be seen from the above examples, the odor grade of the polypropylene composition prepared in the examples reaches 3.0 - 3.5, the TVOC reaches 8 - 14 μgC / g, and the Izod impact strength of the cantilever beam reaches 19 - 40 KJ / m 2 .

[0065] As can be seen from Examples 1 - 4, as the melt mass flow rate of polypropylene increases, the odor grade and Izod impact strength of the cantilever beam both decrease, and the TVOC decreases. Therefore, when the melt mass flow rate of polypropylene is preferably 10 - 100 g / 10 min, the comprehensive performance of the polypropylene composition is better.

[0066] As can be seen from Examples 1, 5 - 6, as the content of PCRPP increases, the odor grade, TVOC, and Izod impact strength of the polypropylene composition all increase. Therefore, when the mass percentage content of PCR polypropylene in the polypropylene is preferably 20 - 50%, the comprehensive performance of the polypropylene composition is better.

[0067] As can be seen from Examples 1 and 7-10, the mass ratio of tungsten boride and potassium bicarbonate has a certain influence on the TVOC and notched Izod impact strength of the polypropylene composition. The mass ratio of tungsten boride and potassium bicarbonate can be selected as 1:(0.5-6.5). Preferably, when the mass ratio of tungsten boride and potassium bicarbonate is 1:(1-3), the comprehensive performance of the polypropylene composition is better. In addition, as can be seen from Example 1 and Comparative Examples 1-4, when tungsten boride and potassium bicarbonate are compounded as adsorbents, the two can synergistically reduce the odor and TVOC of the polypropylene composition, and the reduction effect is better than that of conventional molecular sieve adsorbents.

[0068] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A polypropylene composition, characterized in that, It comprises components in the following parts by weight: 66 - 137 parts of polypropylene, 0 - 31 parts of filler, 4 - 23 parts of toughening agent, 0.2 - 2.7 parts of adsorbent, 0.09 - 2.2 parts of auxiliary agent; the adsorbent comprises 0.08 - 1.2 parts by weight of tungsten boride and 0.15 - 1.5 parts by weight of potassium bicarbonate.

2. The polypropylene composition according to claim 1, wherein The mass ratio of the tungsten boride to the potassium bicarbonate is 1:(0.5 - 6.5).

3. The polypropylene composition according to claim 1, characterized in that, The polypropylene comprises PCR polypropylene, and the mass percentage of the PCR polypropylene in the polypropylene is 20 - 50%.

4. The polypropylene composition according to claim 1, characterized in that, The polypropylene has a melt mass flow rate of 10 - 100 g / 10 min according to ISO1133 - 2012 under the conditions of a test temperature of 230 °C and a load of 2.16 kg.

5. The polypropylene composition according to claim 1, characterized in that, The filler comprises at least one of talc powder, calcium carbonate, and basic magnesium sulfate whiskers.

6. The polypropylene composition according to claim 1, characterized in that, The toughening agent comprises at least one of ethylene - octene random copolymer, ethylene - butene random copolymer, metallocene linear low - density polyethylene, metallocene ethylene - propylene copolymer, and hydrogenated styrene - butadiene - styrene linear triblock copolymer.

7. The polypropylene composition according to claim 1, characterized in that, The auxiliary agent comprises components in the following parts by weight: 0.2 - 0.5 parts of scratch - resistant agent, 0.1 - 0.4 parts of lubricant, and 0.1 - 0.4 parts of antioxidant.

8. The polypropylene composition according to claim 7, wherein The scratch - resistant agent comprises at least one of amide - type and silicone - type scratch - resistant agents; the lubricant comprises stearate - type lubricants, and the antioxidant comprises hindered phenol - type antioxidants and phosphite - type antioxidants.

9. A method for preparing the polypropylene composition according to any one of claims 1-8, characterized in that, It comprises the following steps: The respective raw material components are successively subjected to mixing, melt extrusion, granulation, and drying to obtain the polypropylene composition.

10. Use of the polypropylene composition according to any one of claims 1 - 8 in automotive interiors.

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