WO2023138230A1 - Weather-resistant polypropylene composition and preparation method therefor and application thereof - Google Patents

Abstract

The present invention relates to a weather-resistant polypropylene composition and a preparation method therefor and an application thereof. The weather-resistant polypropylene composition comprises polypropylene, a toughener, a filler, carbon black, an antioxidant, a light stabilizer, and other auxiliary agents. According to the weather-resistant polypropylene composition provided by the present invention, the specific carbon black is added, so that the weather resistance can be effectively improved in the case of adding a small amount of the antioxidant and the light stabilizer, the weather-resistant polypropylene composition has the advantage of low cost, and the problem of appearance defects caused by emigration of the antioxidant, the light stabilizer and the like can be well avoided.

Description

A kind of weather-resistant polypropylene composition and its preparation method and application technical field

The invention belongs to the technical field of engineering plastics, and in particular relates to a weather-resistant polypropylene composition and a preparation method and application thereof.

Background technique

Polypropylene has become the most widely used general-purpose plastic due to its better mechanical properties, rigidity and strength. However, there are unstable tertiary carbon atoms on the polypropylene chain, and it is easy to form tertiary carbon radicals in the presence of light and oxygen, resulting in chain scission and degradation of polypropylene molecular chains, and it is easy to enter the spontaneous oxidation cycle process under the action of oxygen, which eventually leads to poor weather resistance of polypropylene materials. Carbon black is currently the most commonly used plastic colorant, and carbon black is an inorganic pigment with good light stability. During outdoor use, the prepared plastic parts can also be used as a light shielding agent to absorb ultraviolet rays and prolong the service life of materials. Therefore, carbon black is widely used in polypropylene coloring products.

The existing research on improving the weather resistance of polypropylene materials mainly focuses on optimizing the synergistic effect of antioxidants and light stabilizers. For example, the patent discloses a weather-resistant and aging-resistant polypropylene material. The weather resistance performance can be improved by selecting and matching different light stabilizers, such as benzophenone light stabilizers, benzotriazole light stabilizers or hindered amine light stabilizers. The patent discloses a long-glass fiber-reinforced polypropylene composite material. The long-term weather resistance of the polypropylene composite material is improved through the combination of a high-efficiency long-term antioxidant and a light stabilizer that does not react with the ester antioxidant.

Carbon black itself is a good light shielding agent. If the weather resistance of polypropylene materials can be improved by optimizing carbon black itself, it will undoubtedly reduce the amount of other light stabilizers added and reduce costs.

Contents of the invention

The purpose of the present invention is to overcome the defects or deficiencies of the prior art and provide a weather-resistant polypropylene composition. The weather-resistant polypropylene composition provided by the present invention can effectively improve the weather-resistant performance by adding specific carbon black with the addition of a small amount of antioxidants and light stabilizers, has the advantage of low cost, and can better avoid appearance defects caused by migration of antioxidants and light stabilizers.

Another object of the present invention is to provide a preparation method of the weather-resistant polypropylene composition.

Another object of the present invention is to provide the application of the above-mentioned weather-resistant polypropylene composition in the preparation of automobiles and household electrical appliances.

In order to realize the above-mentioned purpose of the invention, the present invention adopts following technical scheme:

A weather-resistant polypropylene composition, comprising the following components in parts by weight:

The specific surface area of the carbon black is 105-270m ² /g, the oil absorption value is 55-70ml/100g, and the mole percentage of oxygen on the surface of the carbon black is 4.2-10.0%.

The specific surface area of carbon black is determined by the following process: referring to ASTM D6556-2016, the nitrogen adsorption method is used for testing, and the specific surface area of carbon black is calculated based on the BET multi-molecular layer adsorption theory. The test results represent the total specific surface area of carbon black.

The oil absorption value of carbon black is determined by the following process: According to the ASTM D2414-2017 test standard, test the minimum amount of dibutyl phthalate required for the voids and surface infiltration of carbon black chain branches or fiber structures, also known as DBP oil absorption value.

The mole percentage of oxygen on the surface of carbon black is determined by the following process: X-ray photoelectron spectroscopy (XPS), using a monochromatic AlKα source (1486.6eV), the test current and voltage are 5mA × 15kV, and the data is corrected based on the C1s (284.80eV) binding energy.

It should be understood that the light stabilizer in the present invention refers to other light stabilizers except carbon black.

The inventors of the present invention have found through many studies that the specific surface area, oil absorption value and mole percentage of oxygen on the surface of carbon black play a key role in weather resistance. Specifically, a larger specific surface area can absorb more ultraviolet light and convert it into heat energy that has a lower impact on the material. If the specific surface area of carbon black is too large, it is not conducive to the dispersion of carbon black, resulting in the formation of carbon black aggregation points; if the specific surface area of carbon black is too small, the effect of absorbing ultraviolet light becomes weaker. A smaller oil absorption value can obtain better dispersion, and a large oil absorption value will cause carbon black to be unable to disperse in the material with a smaller particle size; and an oil absorption value that is too small will also cause aggregation problems. A suitable molar percentage of oxygen on the surface can reduce the amount of peroxide induced by the material during the photoaging process, so that the effect of the light stabilizer can be extended; if the molar percentage of oxygen on the surface is too high or too low, it will affect the number of hydrogen bonds formed between the light stabilizer and the oxygen-containing compound on the surface of carbon black, affect the migration rate of the light stabilizer to the surface, and thus affect the weather resistance of the material.

That is to say, by adjusting the specific surface area, oil absorption value and mole percentage of oxygen on the carbon black surface in the present invention, and adding a small amount of antioxidant and light stabilizer, the weather resistance can be significantly improved, the cost is low, and the appearance defects caused by the addition and migration of a large amount of antioxidant and light stabilizer can be avoided, and the appearance quality is excellent.

Common polypropylenes, tougheners and fillers in the art can be used in the present invention.

Preferably, according to ASTM D1238-2010, the melt mass flow rate of the polypropylene under the conditions of 2.16kg and 230°C is 1.0-150.0g/10min.

Preferably, the toughening agent is one or more of polyolefin elastomer POE, styrene-hydrogenated butadiene block copolymer SEBS or ethylene-propylene-diene rubber EPDM.

The amount of the toughening agent can be selected according to the requirement of the toughening effect, and the preferred amount of the toughening agent is 12-20 parts by weight.

Preferably, the filler is one or more of talcum powder, calcium carbonate, wollastonite, whiskers or glass fibers.

The amount of the filler can be selected according to the requirement of the reinforcing effect, and the preferred weight part of the filler is 10-25 parts.

Preferably, the antioxidant is a mixture of a main antioxidant and a secondary antioxidant, and the weight ratio of the main antioxidant to the secondary antioxidant is (1-3):(3-1).

Further preferably, the primary antioxidant is a hindered phenolic antioxidant, such as tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate] pentaerythritol ester (antioxidant 1010), 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene (antioxidant AO-330), 1,3,5-tris(3,5-di-tert-butyl-4-hydroxy Benzyl)-1,3,5-triazine-2,4,6(1H,3H,5H)trione (antioxidant 3114), etc.

Further preferably, the secondary antioxidant is a phosphite antioxidant, such as tris(2,4-di-tert-butylphenyl)phosphite (antioxidant 168), bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphate (antioxidant PEP-36), bis(3,5-di-tert-butylphenyl)pentaerythritol diphosphite (antioxidant 627), etc.

Preferably, the light stabilizer is a hindered amine light stabilizer, such as UV-3808PP5, LA-402AF, etc.

Preferably, the other additives are lubricants.

More preferably, the lubricant is one or more of calcium stearate, zinc stearate or erucamide.

The amount of other additives can be adjusted according to the requirements of the corresponding properties, and the weight part of other additives is preferably 0.1-0.3 parts.

Preferably, the specific surface area of the carbon black is 107˜194 m ² /g.

Preferably, the mole percentage of oxygen on the surface of the carbon black is 6.5-8.1%.

The preparation method of the weather-resistant polypropylene composition includes the following steps: mixing polypropylene, toughener, filler, carbon black, antioxidant, light stabilizer and other auxiliary agents, melting, extruding and granulating to obtain the weather-resistant polypropylene composition.

Preferably, the preparation method of the weather-resistant polypropylene composition comprises the steps of:

The polypropylene, toughening agent, filler, carbon black, antioxidant, light stabilizer and other additives are mixed in a high mixer to obtain a premixed material, the mixing time is 1 to 3 minutes, and the rotation speed is 1000 to 2000 rpm; then the premixed material is added to a twin-screw extruder to melt, extruded, and vacuum granulated to obtain the weather-resistant polypropylene composition; the temperature of each zone of the twin-screw extruder is 160 to 230°C.

The application of the above-mentioned weather-resistant polypropylene composition in the preparation of automobiles and household electrical appliances is also within the protection scope of the present invention.

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

The weather-resistant polypropylene composition provided by the present invention can effectively improve the weather-resistant performance by adding specific carbon black with the addition of a small amount of antioxidants and light stabilizers, has the advantage of low cost, and can better avoid appearance defects caused by migration of antioxidants and light stabilizers.

Detailed ways

The present invention is further set forth below in conjunction with embodiment. These examples are only for illustrating the present invention and are not intended to limit the scope of the present invention. The experimental methods not specifying specific conditions in the following examples are usually according to the conventional conditions in this field or according to the conditions suggested by the manufacturer; the raw materials and reagents used, if not otherwise specified, are raw materials and reagents that can be obtained from commercial channels such as conventional markets. Any insubstantial changes and substitutions made by those skilled in the art on the basis of the present invention fall within the scope of the present invention.

The partial reagents that each embodiment of the present invention and comparative examples select are described as follows:

Polypropylene 1: BX3900, SK Korea, with a melt mass flow rate of 60g/10min (ASTM D1238-2010, 2.16kg, 230°C, the same below);

Polypropylene 2: MH7900, Korea LG Chemical, melt mass flow rate is 150g/10min;

Polypropylene 3: BX3920, SK Korea, melt mass flow rate is 90g/10min;

Polypropylene 4: BX3800, Korea SK, melt mass flow rate is 30g/10min;

Polypropylene 5: EPS30R, Dushanzi Petrochemical, with a melt mass flow rate of 1.0g/10min;

Toughener 1: polyolefin elastomer POE, Engage8842, Dow Chemical;

Toughener 2: SEBS 1657, Kraton;

Filler 1: talcum powder, commercially available;

Filler 2: calcium carbonate, commercially available;

Carbon black 1: Raven 2000, BIRLA company, the specific surface area is 194m ² /g, the oil absorption value is 70ml/100g, and the molar percentage of oxygen content on the carbon black surface is 6.50%;

Carbon black 2: Raven 2500 Ultra, BIRLA company, the specific surface area is 270m ² /g, the oil absorption value is 65ml/100g, and the molar percentage of oxygen content on the carbon black surface is 10.0%;

Carbon black 3: Raven 1170, BIRLA company, the specific surface area is 107m ² /g, the oil absorption value is 55ml/100g, and the molar percentage of oxygen content on the carbon black surface is 8.1%;

Carbon black 4: 600L, Cabot company, the specific surface area is 240m ² /g, the oil absorption value is 68ml/100g, and the molar percentage of oxygen content on the carbon black surface is 4.20%;

Carbon black 5: Raven 1300 Ultra, BIRLA company, the specific surface area is 115m ² /g, the oil absorption value is 95ml/100g, and the molar percentage of oxygen content on the carbon black surface is 9.30%;

Carbon black 6: Raven 1020, BIRLA company, the specific surface area is 95m ² /g, the oil absorption value is 58ml/100g, and the molar percentage of oxygen content on the carbon black surface is 5.20%;

Carbon black: 7: Denka Black Granule, NEC, specific surface area is 65m ² /g, oil absorption value is 160ml/100g, and the molar percentage of oxygen on carbon black surface is 1.74%;

Carbon black 8: Raven 1255, BIRLA company, the specific surface area is 122m ² /g, the oil absorption value is 66ml/100g, and the molar percentage of oxygen content on the carbon black surface is 10.8%;

Antioxidant 1: composed of primary antioxidant 1 and secondary antioxidant 1 in a weight ratio of 1:1;

Antioxidant 2: composed of primary antioxidant 1 and auxiliary antioxidant 1 in a weight ratio of 2:3;

Antioxidant 3: composed of primary antioxidant 1 and secondary antioxidant 1 in a weight ratio of 3:1;

Antioxidant 4: composed of primary antioxidant 2 and secondary antioxidant 2 in a weight ratio of 1:1;

Primary antioxidant 1: antioxidant 1010, commercially available;

Primary antioxidant 2: antioxidant AO-330, commercially available;

Secondary antioxidant 1: antioxidant 168, commercially available;

Secondary antioxidant 2: antioxidant PEP-36, commercially available;

Light stabilizer 1: UV-3808PP5, commercially available;

Light stabilizer 2: LA-402AF, commercially available;

Lubricant: calcium stearate, commercially available.

The polypropylene composition in the embodiment of the present invention and comparative example is prepared through the following process:

(1) Take each component by weight ratio, join in the high mixer and mix for 2 minutes, and the rotating speed is 2000 rpm to obtain the premix;

(2) The premix is melted and extruded by a twin-screw extruder, and the temperature of each zone of the screw is 160°C, 190°C, 210°C, 210°C, 230°C, 230°C, 230°C, 230°C, 230°C, 230°C, 230°C, and vacuum granulated.

The polypropylene composition prepared in each example and comparative example was injection molded into a 100mm*100mm*2mm sample piece, and the following tests were carried out.

Weather resistance test: According to SAE J2527-2004, the irradiation energy is 2500KJ/m ² ; test the changes of L, a, b values of the sample before and after the weather resistance test, and calculate dE, the smaller the dE, the better the weather resistance of the material.

Appearance quality: observe with naked eyes whether there is any visible whitening and pulverization.

Examples 1-16

This example provides a series of weather-resistant polypropylene compositions, and the parts by weight and performance test results of each component in the formulation are shown in Table 1 and Table 2.

Formulation (part) and performance test result of table 1 embodiment 1～8

Formulation (part) and performance test result of table 2 embodiment 9～16

Comparative example 1-4

This comparative example provides a series of polypropylene compositions, and the parts by weight and performance test results of each component in the formula are shown in Table 3.

Table 3 The formula (parts) and performance test results of comparative examples 1 to 4

From the above test results, it can be known that the weather-resistant polypropylene compositions provided by Examples 1-16 have better weather resistance and appearance quality, and the performance of Example 1 is the best. At least one of the specific surface area, oil absorption value, and oxygen mole percentage of the carbon black selected in Comparative Examples 1 to 4 is improperly regulated, and none of them can effectively improve the weather resistance.

Those skilled in the art will appreciate that the embodiments herein are to help readers understand the principles of the present invention, and it should be understood that the protection scope of the present invention is not limited to such specific statements and embodiments. Those skilled in the art can make various other specific modifications and combinations based on the technical revelations disclosed in the present invention without departing from the essence of the present invention, and these modifications and combinations are still within the protection scope of the present invention.

Claims (10)

1. A weather-resistant polypropylene composition is characterized in that it comprises the following components in parts by weight:

   

   The specific surface area of the carbon black is 105-270m ² /g, the oil absorption value is 55-70ml/100g, and the mole percentage of oxygen on the surface of the carbon black is 4.2-10.0%.
2. The weather-resistant polypropylene composition according to claim 1, characterized in that, according to ASTM D1238-2010, the melt mass flow rate of the polypropylene under the conditions of 2.16kg and 230°C is 1.0-150.0g/10min.
3. The weather-resistant polypropylene composition according to claim 1, wherein the toughening agent is one or more of polyolefin elastomer POE, styrene-hydrogenated butadiene block copolymer SEBS or EPDM.
4. The weather-resistant polypropylene composition according to claim 1, wherein the filler is one or more of talcum powder, calcium carbonate, wollastonite, whiskers or glass fibers.
5. The weather-resistant polypropylene composition according to claim 1, wherein the antioxidant is a mixture of a main antioxidant and an auxiliary antioxidant, and the weight ratio of the main antioxidant and the auxiliary antioxidant in the mixture is (1～3):(3～1); the light stabilizer is a hindered amine light stabilizer.
6. The weather-resistant polypropylene composition according to claim 1, wherein the other auxiliary agent is a lubricant.
7. The weather-resistant polypropylene composition according to claim 1, wherein the specific surface area of the carbon black is 107-194 m ² /g.
8. The weather-resistant polypropylene composition according to claim 1, wherein the mole percentage of oxygen on the surface of the carbon black is 6.5-8.1%.
9. The preparation method of the weather-resistant polypropylene composition according to any one of claims 1-8, characterized in that it comprises the following steps: mixing polypropylene, toughening agent, filler, carbon black, antioxidant, light stabilizer and other auxiliary agents, melting, extruding, and granulating to obtain the weather-resistant polypropylene composition.
10. The application of the weather-resistant polypropylene composition according to any one of claims 1 to 8 in the preparation of automobiles and home appliances.