CN116426073A - Flame-retardant weather-resistant polypropylene composite material and preparation method and application thereof - Google Patents

Abstract

The invention belongs to the technical field of high polymer materials, and discloses a flame-retardant weather-resistant polypropylene composite material, and a preparation method and application thereof. The invention discloses a flame-retardant weather-resistant polypropylene composite material, which comprises the following components in parts by weight: 1-32 parts of homo-polypropylene; 20-60 parts of polypropylene copolymer, 15-18 parts of brominated flame retardant, 5-6 parts of antimonous oxide, 15-25 parts of talcum powder, 0.2-1 part of carbon black and 0.1-1.5 parts of auxiliary agent. The composite material prepared by the invention has excellent weather resistance, flame retardance and mechanical property and low cost. Can be used for preparing products such as parts which are in long-term contact with direct sunlight.

Description

Flame-retardant weather-resistant polypropylene composite material and preparation method and application thereof

Technical Field

The invention relates to the technical field of high polymer materials, in particular to a flame-retardant weather-resistant polypropylene composite material, and a preparation method and application thereof.

Background

Polypropylene is a universal plastic, has the advantages of high melting point, low density, good chemical stability, easy recovery, low price and the like, and has wide application prospect in the fields of automotive interiors and the like. Since a vehicle is exposed to sunlight for a long period of time during use, an interior part thereof is required to have excellent flame retardancy, weather resistance and mechanical properties. In the prior art, the halogen-free flame retardant polypropylene material has excellent flame retardant and weather resistance, but has poor mechanical and processing properties. The brominated flame-retardant polypropylene material has excellent flame retardant property and mechanical property, but has poor weather resistance. The poor weather resistance of brominated flame retardant polypropylene is determined by the nature of brominated flame retardant and the antagonism between brominated flame retardant and weather resistant agent. The brominated flame retardant generates aryl free radicals and brominated free radicals under the conditions of illumination, heating and the like. The two free radicals can be added into peroxide generated in the photo-aging process to decompose, so that the photo-aging process is accelerated, and the weatherability of the brominated flame-retardant polypropylene material is poor. On the other hand, bromine radicals react with polypropylene molecular chains to generate hydrobromic acid, and further react with light stabilizers to generate ammonium salts, so that the light stabilizers are consumed, and meanwhile, the formation of nitro radicals is inhibited, and the effect of the weather-proof agent is inhibited.

At present, a common solution for improving the weather resistance of brominated flame-retardant polypropylene is to add a large amount of light stabilizer, ultraviolet absorber, acid absorber, content of toner (such as carbon black) and the like into the material. The method finally leads to complex processing process, greatly increased material cost, reduced thermo-oxidative stability and insignificant weather resistance improvement effect of the brominated flame-retardant polypropylene. Chinese patent document CN114213749a discloses a flame retardant polypropylene material by using an ultraviolet absorber, a light stabilizer and a metal oxide as a light aging resistant component. The material has complex components, and metal components are indirectly introduced, so that the influence on the thermo-oxidative stability of the material is unknown. Chinese patent document CN103275394B discloses a weather-proof flame-retardant polypropylene composite material and a preparation method thereof, wherein the polypropylene composite material takes carbon black as a weather-proof modifier, and the addition amount is 1.5-2.5wt%. Such high levels of carbon black necessarily lead to reduced processability of the polypropylene composite and to reduced thermal stability of the polypropylene composite.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a flame-retardant weather-resistant polypropylene composite material with excellent weather resistance, flame retardant property and mechanical property and low cost, and a preparation method and application thereof, so as to solve the problems of poor weather resistance and complex formula of brominated flame-retardant polypropylene in the prior art.

In order to achieve the above purpose, the technical scheme adopted by the invention is as follows:

in a first aspect, the invention provides a flame-retardant weather-resistant polypropylene composite material, which comprises the following components in parts by weight: 1-32 parts of homo-polypropylene; 20-60 parts of copolymerized polypropylene, 15-18 parts of brominated flame retardant, 5-6 parts of antimonous oxide, 15-25 parts of talcum powder, 0.2-1 part of carbon black and 0.1-1.5 parts of auxiliary agent;

the particle size of the talcum powder is 3000-5000 meshes;

the ethylene propylene rubber content (measured by high temperature gel permeation chromatography) in the polypropylene composite material is 12-18%.

According to the invention, the specific content of homo-polypropylene, co-polypropylene, brominated flame retardant and antimony trioxide are adopted, talcum powder with specific particle size can play a synergistic effect, so that the EPR content in the prepared flame-retardant weather-proof polypropylene composite material is 12% -18%, and as the phase-splitting structure exists between polypropylene and EPR in the composite material, the composite material has a unique phase structure, after the composite material forms a unique phase structure, the brominated flame retardant and talcum powder are dispersed in the polypropylene phase, the antimony trioxide is dispersed in the EPR phase, and a protective layer is formed on the surface of the composite material by the specific EPR content, so that the contact between the brominated flame retardant and the antimony trioxide is reduced. When ultraviolet light irradiates the surface of the composite material, the antimony trioxide consumes the ultraviolet light, so that the irradiation effect of the ultraviolet light on the brominated flame retardant in the polypropylene phase is reduced, the decomposition of the brominated flame retardant is reduced, the degradation of the brominated flame retardant on the polypropylene is also reduced, and the weather resistance of the composite material is improved; the alkaline talcum powder has the adsorption effect on acidic substances such as hydrobromic acid generated by decomposition of the brominated flame retardant, so that the weather resistance of the composite material is improved.

Wherein, the content of the brominated flame retardant is critical to the flame retardance and the weather resistance. The brominated flame retardant has low content and the flame retardant property of the composite material is poor; the higher the brominated flame retardant content, the higher the adverse effect on weatherability, resulting in poor weatherability of the composite. The particle size of the talcum powder plays a role in the weather resistance of the composite material, the particle size is too large, the comparison area of the talcum powder is small, the adsorption effect on acidic substances is weak, and the weather resistance improvement effect is not obvious; the talcum powder has small particle size and large specific surface area, and is easier to decompose the brominated flame retardant in the processing process, so that the weather resistance is poor.

Moreover, carbon black has an ultraviolet shielding effect, but higher carbon black content results in processing difficulties, increased cost, and reduced thermal aging resistance. According to the invention, by regulating and controlling the phase structure of the brominated flame-retardant polypropylene, under the condition of the addition amount of the conventional carbon black, the weather resistance of the composite material can be greatly improved, so that the composite material is ensured to have excellent processability, and environmental pollution in the processing process and the reduction of the thermal aging resistance of the composite material are avoided.

As a preferable implementation mode of the flame-retardant weather-resistant polypropylene composite material, the content of the polypropylene copolymer is 32-60 parts.

As a preferable implementation mode of the flame-retardant weather-resistant polypropylene composite material, the ethylene propylene rubber content in the copolymer polypropylene is 15% -40%; preferably, the ethylene propylene rubber content in the copolymer polypropylene is 29-37.8%.

As a preferable implementation mode of the flame-retardant weather-resistant polypropylene composite material, the brominated flame retardant is at least one of decabromodiphenylethane, tetrabromobisphenol A, octabromoether and octabromoS ether.

As a preferable implementation mode of the flame-retardant weather-resistant polypropylene composite material, the auxiliary agent comprises 0.1-0.3 part of main antioxidant, 0.1-0.3 part of auxiliary antioxidant and 0.2-0.5 part of light stabilizer.

As a preferable implementation mode of the flame-retardant weather-resistant polypropylene composite material, the main antioxidant is a hindered phenol antioxidant; the auxiliary antioxidant is phosphite antioxidant; the light stabilizer is a hindered amine light stabilizer.

In the flame-retardant weather-resistant polypropylene composite material, the light stabilizer has an effect of improving the weather resistance of the composite material, but the higher the content is, the better the weather resistance of the composite material is. When the content exceeds 0.3 part, the weather resistance of the composite material is improved to a platform stage, and the cost of the composite material is increased.

In a second aspect, the invention provides a preparation method of the flame-retardant weather-resistant polypropylene composite material, which comprises the following steps:

the components are respectively weighed and mixed; extruding after melting, granulating and cooling.

As a preferred embodiment of the preparation method of the present invention, the mixing is carried out at a rotational speed of 200r/min to 500r/min for 5min to 8min.

In the third aspect, the flame-retardant weather-resistant polypropylene composite material is applied to parts which are in long-term contact with direct sunlight, such as automobile interior trim parts, exterior trim parts and the like.

Compared with the prior art, the invention has the beneficial effects that:

the invention relates to a brominated flame-retardant weather-resistant polypropylene composite material, which comprises homo-polypropylene, co-polypropylene, brominated flame retardant, antimony trioxide, talcum powder, carbon black and auxiliary agent. According to the invention, the phase structure of polypropylene and EPR in the composite material is effectively regulated and controlled by regulating and controlling the content of the polypropylene matrix, and the polypropylene composite material with excellent flame retardance, weather resistance and mechanical property is obtained under the action of a conventional amount of brominated flame retardant and antimony trioxide by the synergistic effect of the components, so that the formula composition is simple. The prepared composite material meets the UL94 vertical burning test V-0 (spline thickness 1.5 mm) grade, SAE J2412 1240kJ/m ² After photo-aging test, delta E is less than or equal to 1.5, flexural modulus is more than or equal to 2200MPa, notch impact is more than or equal to 4.0kJ/m ² 。

Drawings

FIG. 1 is a cross-sectional morphology transmission electron microscope image of a flame retardant weatherable polypropylene composite of comparative example 4;

FIG. 2 is a scanning electron microscope image of the cross-sectional surface etching morphology of the flame retardant and weather resistant polypropylene composite material of comparative example 4;

FIG. 3 is a cross-sectional morphology transmission electron microscope image of the flame retardant weatherable polypropylene composite of comparative example 5;

FIG. 4 is a scanning electron microscope image of the cross-sectional surface etching morphology of the flame retardant and weather resistant polypropylene composite material of comparative example 5.

Detailed Description

For a better description of the objects, technical solutions and advantages of the present invention, the present invention will be further described with reference to the following specific examples. It will be appreciated by persons skilled in the art that the specific embodiments described herein are for purposes of illustration only and are not intended to be limiting. The Ethylene Propylene Rubber (EPR) content (in mass percent) in the material is measured by high temperature gel permeation chromatography.

1. The raw materials used in the examples and comparative examples are described below, but are not limited to these materials:

(1) Homo-polypropylene

PP HP500N, purchased from the middle sea shell petrochemical company, inc;

(2) Co-polypropylene

PP EP548R, EPR content: 18%, purchased from Zhonghai Shell petrochemical Co., ltd;

PP K9017, EPR content: 20%, purchased from taiwan chemical fiber stock, inc;

PP 8285e1, epr content: 29%, purchased from exxon mobil;

PP SP179, EPR content: 37.8% from taiwan chemical fiber stock, inc;

PP LH-KA30, EPR content: 40%, available from New materials technology Inc.

(3) Flame retardant

Decabromodiphenylethane, SAYTEX 8010, available from yabao in the united states;

tetrabromobisphenol A, FR-1524, purchased from Israel dead sea;

octabromoether, XZ-6800, available from Shandong Brother technologies Co., ltd;

octabromos ether, available from maritime ocean chemical engineering limited;

antimony trioxide, S-05N, available from antimonial Inc. of Chang Dechen.

(4) Talc powder:

t01, 1000 mesh particle size, available from Dendong TIANCIS flame retardant materials technology Co., ltd;

TYT-777A with particle size of 3000 mesh is purchased from sea city additive chemical industry Co., ltd;

HTPultra5L, with a particle size of 5000 mesh, purchased from Guangzhou Hijia chemical Co., ltd;

HF-6000A, with a particle size of 6000 mesh, is available from Yongao chemical New Material Co., ltd.

(5) Carbon black

M717, available from Kabot chemical Co., ltd;

(6) Antioxidant

And (3) a main antioxidant: hindered phenol antioxidant Y-001 is purchased from Yingkou wind-solar chemical industry Co., ltd;

auxiliary antioxidant: phosphite antioxidant Y-002 is purchased from Yingkou city wind-solar chemical industry Co.

(7) Light stabilizers

Hindered amine compound light stabilizer, T-81, is purchased from Beijing Tinodon auxiliary agent Limited liability company.

The composition of the flame retardant and weather resistant polypropylene composites of examples 1 to 11 and comparative examples 1 to 8 are shown in Table 1.

The preparation method of the flame-retardant weather-resistant polypropylene composite materials of examples 1 to 11 and comparative examples 1 to 8 is as follows:

respectively weighing homo-polypropylene, co-polypropylene, brominated flame retardant, antimony trioxide, talcum powder, carbon black, main antioxidant, auxiliary antioxidant and light stabilizer, adding into a high-speed mixer, and mixing at a mixing speed of 200-500 r/min for 5-8 min to obtain a mixture A; and adding the mixture A into a double-screw extruder for melt extrusion, and granulating and cooling to obtain the flame-retardant weather-resistant polypropylene composite material.

2. The properties of the flame retardant and weather resistant polypropylene composites of examples 1 to 11 and comparative examples 1 to 8 were examined as follows:

(1) Flame retardant Performance test

Vertical burn performance of 1.5mm thick bars was tested according to the plastic fire rating UL94 standard;

(2) Weather resistance test

Weather resistance of the test sample plate is tested according to SAE J2412 detection standard, and irradiation energy is 1240kJ/m ² The detection time is 792h;

(3) Flexural modulus test

Testing according to the standard of ISO 178-2019 plastic bending property determination, wherein the testing speed is 2mm/min;

(4) Simple beam notch impact strength test

The test was carried out according to the ISO 179/1eA-2010 Plastic pendulum impact Property measurement standard. The flame retardant and weather resistant properties and the flexural modulus and notched impact test results of the flame retardant and weather resistant polypropylene composites of examples 1 to 11 and comparative examples 1 to 8 are shown in Table 1.

Table 1 Components (parts by weight) of the composite materials

Table 1 shows the components (parts by weight) of the composite material

As can be seen from comparing the flame retardant and weather resistant polypropylene composites of examples 1 to 11 and comparative examples 1 to 8: the invention adopts the homo-polypropylene, the co-polypropylene, the brominated flame retardant, the antimonous oxide and the talcum powder with specific particle size, and can play a synergistic role, so that the prepared polypropylene composite material has excellent weather resistance (V-0), weather resistance (delta E is less than or equal to 1.5), rigidity and toughness.

After the composite material forms a unique phase structure, the brominated flame retardant and talcum powder are dispersed in a polypropylene phase, the antimonous oxide is dispersed in an EPR phase, and a protective layer is formed on the surface of the composite material by the specific EPR content, so that the contact between the brominated flame retardant and the antimonous oxide is reduced. When ultraviolet light irradiates the surface of the composite material, the antimony trioxide consumes the ultraviolet light, so that the irradiation effect of the ultraviolet light on the brominated flame retardant in the polypropylene phase is reduced, the decomposition of the brominated flame retardant is reduced, the degradation of the brominated flame retardant on the polypropylene is also reduced, and the weather resistance of the composite material is improved; the alkaline talcum powder has the adsorption effect on acidic substances such as hydrobromic acid generated by decomposition of the brominated flame retardant, so that the weather resistance of the composite material is improved.

Comparative example 3 the prepared composite had an EPR content of 7.9% and not in the range of 12% to 18% compared with example 4, and fig. 1 is a cross-sectional morphology of the material of comparative example 3 having an EPR content of 12% or less, wherein the EPR content is in the form of gray spheres, the Talc (Talc) is in the form of gray flakes, and the flame retardant (DBDPE) is in the form of black. The EPR distribution size of the prepared composite material is smaller, the polypropylene and the EPR do not have a phase separation structure in the composite material, and the weather resistance of the composite material is poor. To further illustrate the differential effect of EPR content on the morphology of the material, the material was immersed in toluene at 50 ℃ and sonicated for 24 hours to etch the material (EPR phase may be dissolved to pit the surface of the material). FIG. 2 shows the etched surface morphology of the material with EPR content below 18% in comparative example 3, with less pits.

Comparative example 4 the prepared composite material had an EPR content of 18.9% and not in the range of 12% to 18% compared with example 4, and fig. 3 is a cross-sectional morphology of a material having an EPR content of 18% or more, wherein the EPR content is in the form of gray spheres, the Talc (Talc) is in the form of gray flakes, and the flame retardant (DBDPE) is in the form of black. The EPR distribution size of the prepared composite material is smaller, and the display is more obvious. The polypropylene and EPR have no phase-splitting structure in the composite material, so that the flame retardant property of the composite material is reduced. To further illustrate the differential effect of EPR content on material morphology, the material was etched with toluene (EPR phase may be dissolved to pit the material surface). FIG. 4 shows the morphology of the etched surface of the material with EPR content of 18% or more in comparative example 4, in which the pits are many and can be basically connected into a sheet.

Therefore, it is considered that after the EPR content reaches 12% to 18%, a protective layer containing EPR as a main component is formed on the surface of the composite material. In order to prove that the weather-resistant agent is dispersed in EPR, the composite material prepared in the embodiment 4 is subjected to toluene etching, the EPR solution after toluene etching is dried to constant weight at 80 ℃, the main components of the dried product are tested, and the main components of the dried product are found to be the EPR and the weather-resistant agent by infrared spectrum comparison with the independent components in the material formula. The weather-proof agent is mainly distributed in the EPR, when the EPR content reaches 12% -18%, ultraviolet rays can be effectively absorbed, and the material is prevented from being irradiated by the ultraviolet rays to cause the decomposition of the flame retardant.

Comparative example 1 compared with example 2, it can be seen that the EPR content of the composite material is less than 12%, and the weather resistance of the composite material is poor.

Comparative example 2 the EPR content of the composite material was higher than 18% compared with example 4, and it can be seen that the weather resistance of the composite material was poor.

Compared with the comparative examples 5 and 6 and the example 4, it can be seen that the adopted talcum powder has smaller (1000 meshes) or larger (6000 meshes) particle size, and the prepared composite material has poorer weather resistance.

Comparative examples 7 and 8 are compared with example 4, and it can be seen that the brominated flame retardant is too low or too high in amount, and the prepared composite material is poor in flame retardant property or weather resistance.

In summary, from key factors affecting the weather resistance of the brominated flame-retardant polypropylene composite material, the polypropylene composite material with excellent flame retardance, weather resistance and mechanical properties can be prepared only if all components are in a proper dosage range under the conditions of specific homo-polypropylene content, co-polypropylene content, EPR content in the co-polypropylene, EPR content in the prepared polypropylene composite material, talcum powder particle size and brominated flame retardant content by optimizing the type and content of the polypropylene and combining the synergistic effect of talcum powder and carbon black in the composite material. The prepared polypropylene composite material can be suitable for parts which are in long-term contact with direct sunlight in automobile interiors.

Finally, it should be noted that the above embodiments are only for illustrating the technical solution of the present invention and not for limiting the scope of the present invention, and although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solution of the present invention may be modified or substituted equally without departing from the spirit and scope of the technical solution of the present invention.

Claims (9)

1. The flame-retardant weather-resistant polypropylene composite material is characterized by comprising the following components in parts by weight: 1-32 parts of homo-polypropylene; 20-60 parts of copolymerized polypropylene, 15-18 parts of brominated flame retardant, 5-6 parts of antimonous oxide, 15-25 parts of talcum powder, 0.2-1 part of carbon black and 0.1-1.5 parts of auxiliary agent;

the particle size of the talcum powder is 3000-5000 meshes;

the ethylene propylene rubber content in the polypropylene composite material is 12-18%.

2. The flame-retardant and weather-resistant polypropylene composite material according to claim 1, wherein the content of the copolymerized polypropylene is 32-60 parts.

3. The flame-retardant and weather-resistant polypropylene composite material according to claim 1, wherein the ethylene propylene rubber content in the copolymer polypropylene is 15% -40%; preferably, the ethylene propylene rubber content in the copolymer polypropylene is 29-37.8%.

4. The flame retardant and weatherable polypropylene composite according to claim 1, wherein the brominated flame retardant is at least one of decabromodiphenylethane, tetrabromobisphenol a, octabromoether, octabromos ether.

5. The flame-retardant and weather-resistant polypropylene composite material according to claim 1, wherein the auxiliary agent comprises 0.1-0.3 part of a main antioxidant, 0.1-0.3 part of an auxiliary antioxidant and 0.2-0.5 part of a light stabilizer.

6. The flame retardant weatherable polypropylene composite of claim 5, wherein the primary antioxidant is a hindered phenolic antioxidant; the auxiliary antioxidant is phosphite antioxidant; the light stabilizer is a hindered amine light stabilizer.

7. A method for preparing the flame-retardant and weather-resistant polypropylene composite material according to any one of claims 1 to 6, which is characterized by comprising the following steps:

the components are respectively weighed and mixed; extruding after melting, granulating and cooling.

8. The method according to claim 7, wherein the mixing is performed at a rotational speed of 200r/min to 500r/min for 5min to 8min.

9. Use of the flame retardant and weather resistant polypropylene composite material as defined in any one of claims 1 to 6 in automotive parts.

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