Brominated flame-retardant polypropylene composite material as well as preparation method and application thereof

Abstract

The invention relates to a brominated flame-retardant polypropylene composite material as well as a preparation method and application thereof, and the brominated flame-retardant polypropylene composite material comprises the following components in parts by weight: 87-92.5 parts of polypropylene resin, 5-8 parts of a brominated flame retardant, 2-4 parts of a flame-retardant synergist, 0.3-0.6 part of stearate and 0.3-0.6 part of tris (nonylphenol) phosphite. The stearate and the tris (nonylphenol) phosphite are added into the brominated flame-retardant polypropylene composite material at the same time, so that the yellow grain problem of the brominated flame-retardant polypropylene composite material in the injection molding process can be effectively improved (the thermal retention color difference is small), and the flame-retardant property consistency is improved. In addition, the oxygen index of the brominated flame-retardant polypropylene composite material is not lower than 24, and the brominated flame-retardant polypropylene composite material has excellent flame retardance.

Description

Technical Field

[0001] The present invention relates to the field of modified plastics, and more specifically, to a brominated flame retardant polypropylene composite material, a preparation method thereof, and an application thereof. Background Art

[0002] Polypropylene (PP) resin has the characteristics of low density and low odor, and is widely used in interior parts of automobiles. However, the interior parts of automobiles require good flame retardant performance. Ordinary PP resin has a low oxygen index and needs to be flame retardant modified. For polypropylene materials used in automobiles, the oxygen index is required to be not less than 24. And since they need to face severe cold and hot environments during use, the polypropylene materials also need to have high and low temperature resistance, generally need to withstand a high temperature of 80 °C without deformation and a low temperature of -40 °C without cracking. Adding brominated flame retardants can not only play a flame retardant role, but also meet the requirement of high toughness of polypropylene materials in high and low temperature environments. However, during the hot processing process, the brominated flame retardant will have a certain degree of thermal decomposition, resulting in a decrease in the effective content of the flame retardant in the polypropylene material, thus resulting in differences in the flame retardant performance of samples of the same batch.

[0003] In addition, during the injection molding process, temporary shutdown is likely to lead to an extended heating time of the brominated flame retardant, and the brominated flame retardant undergoes a decomposition reaction to gradually release free bromine and bromides, which will cause yellow streaks to appear at the injection molding gate, which will affect the appearance of the polypropylene material, and thus also affect its application in interior parts of automobiles.

[0004] Chinese Patent "High-gloss low-surface-precipitation flame retardant polypropylene composite and preparation method thereof" discloses a high-gloss low-surface-precipitation flame retardant polypropylene composite, the components of which include PP resin, octabromo S ether and other additives. The prepared polypropylene composite has good flame retardant performance, mechanical properties and heat distortion temperature, but it does not pay attention to the yellow streaks phenomenon that appears during the injection molding process of the polypropylene composite and the consistency of the flame retardant performance.

[0005] Therefore, it is necessary to develop a polypropylene material with good consistency in flame retardant performance and capable of avoiding the appearance of yellow streaks during injection molding to meet the market demand. Summary of the Invention

[0006] The primary object of the present invention is to overcome the problems that the temporary shutdown during the processing of the existing brominated flame retardant polypropylene composite material affects the consistency of the flame retardant performance and the appearance of yellow streaks at the injection molding gate, and to provide a brominated flame retardant polypropylene composite material. Adding stearate and tris(nonylphenyl) phosphite to the brominated flame retardant polypropylene composite material can effectively improve the yellow streaks problem (small thermal retention color difference) during the injection molding process and improve the consistency of the flame retardant performance.

[0007] A further object of the present invention is to provide a method for preparing a brominated flame-retardant polypropylene composite material.

[0008] Another object of the present invention is to provide the application of the above brominated flame-retardant polypropylene composite material in the preparation of household items, electronic components, household appliances, gardening equipment, medical technology equipment, motor vehicle parts or vehicle body parts.

[0009] The above objects of the present invention are achieved by the following technical solutions:

[0010] A brominated flame-retardant polypropylene composite material, comprising the following components in parts by weight: 87-92.5 parts of polypropylene resin, 5-8 parts of brominated flame retardant, 2-4 parts of flame retardant synergist, 0.3-0.6 part of stearate, and 0.3-0.6 part of tris(nonylphenyl) phosphite.

[0011] In the present invention, the addition of the brominated flame retardant and the flame retardant synergist can improve the flame retardant performance of the brominated flame-retardant polypropylene composite material.

[0012] The inventors of the present invention found through research that the simultaneous addition of stearate and tris(nonylphenyl) phosphite can effectively improve the yellow stripe problem (small thermal retention color difference) during the injection molding process of the brominated flame-retardant polypropylene composite material and can improve the consistency of the flame retardant performance. The principle may be that: the added stearate can react with the bromide generated during the injection molding process of the brominated flame retardant, reducing the formation of bromine free radicals in the material system, and thus inhibiting the further decomposition of the brominated flame retardant caused by bromine free radicals; the added tris(nonylphenyl) phosphite reduces the influence of the shear heat during the processing on the brominated flame retardant in the composite material through the rheology-promoting effect. The combined action of the two aspects effectively inhibits the decomposition of the brominated flame retardant, thereby improving the yellow stripe phenomenon during the injection molding process and improving the consistency of the flame retardant performance (good consistency of the flame retardant performance of samples in the same batch).

[0013] In the present invention, the polypropylene resin is used as the main resin, and its content accounts for more than 60 wt% of the brominated flame-retardant polypropylene composite material.

[0014] Preferably, the stearate is at least one of aluminum stearate, magnesium stearate or potassium stearate.

[0015] More preferably, the stearate is aluminum stearate. When the stearate is aluminum stearate, the brominated flame-retardant polypropylene composite material has a larger oxygen index and a smaller thermal retention color difference.

[0016] Preferably, the flame retardant synergist is an antimony-containing compound.

[0017] More preferably, the antimony-containing compound is at least one of antimony trioxide, antimony tetroxide or antimony pentoxide.

[0018] Preferably, the melt flow rate of the polypropylene resin at 230°C and 2.16 kg is 1 to 70 g / 10 min.

[0019] More preferably, the melt flow rate of the polypropylene resin at 230°C and 2.16 kg is 5 to 35 g / 10 min.

[0020] In the present invention, the melt flow rate of the polypropylene resin can be measured according to ISO 1133-1:2022.

[0021] Preferably, the polypropylene resin is at least one of homopolypropylene and copolymerized polypropylene.

[0022] Preferably, the brominated flame retardant is at least one of octabromoether, methyl octabromoether, and octabromo S-ether.

[0023] Preferably, the brominated flame-retardant polypropylene composite further comprises the following components in parts by weight: 0.5 to 1 part of other additives.

[0024] More preferably, the processing aid includes but is not limited to lubricants.

[0025] Further preferably, the lubricant is at least one of ethylene bisstearamide, erucamide, and oleamide.

[0026] Without affecting the effects of the present invention, the brominated flame-retardant polypropylene composite further comprises 3 to 7 parts of reinforcing filler and 2 to 5 parts of toughening agent.

[0027] Preferably, the reinforcing filler is at least one of talc powder, mica powder, and barium sulfate.

[0028] Preferably, the toughening agent is at least one of ethylene-octene copolymer, ethylene propylene diene monomer rubber, and ethylene-vinyl acetate copolymer.

[0029] The preparation method of the above-mentioned brominated flame-retardant polypropylene composite comprises the following steps: weighing each component according to the formula and mixing, followed by melt extrusion and pelletizing to obtain the brominated flame-retardant polypropylene composite.

[0030] Preferably, the melt extrusion is carried out in an extruder.

[0031] More preferably, the screw speed of the extruder is 300 to 600 revolutions per minute, and the temperature is 120 to 200°C.

[0032] Further preferably, the temperatures of each zone of the extruder are as follows: the temperature of zone 1 is 120-140°C, the temperature of zone 2 is 160-180°C, the temperature of zone 3 is 160-180°C, the temperature of zone 4 is 160-180°C, the temperature of zone 5 is 170-190°C, the temperature of zone 6 is 170-190°C, the temperature of zone 7 is 170-190°C, the temperature of zone 8 is 160-180°C, and the temperature of zone 9 is 160-180°C.

[0033] The present invention also provides the use of the above-mentioned bromine-based flame-retardant polypropylene composite material for preparing household items, electronic components, household appliances, gardening equipment, medical technology equipment, motor vehicle parts or vehicle body parts.

[0034] In particular, the above-mentioned bromine-based flame-retardant polypropylene composite material can be used to prepare components with good flame-retardant properties, flame-retardant property consistency and good appearance.

[0035] In particular, it can be used to prepare automotive parts and / or household appliance parts materials, and is especially suitable for automotive interior parts.

[0036] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0037] Adding stearate and tris(nonylphenyl) phosphite to the bromine-based flame-retardant polypropylene composite material of the present invention can effectively improve the yellow stripe problem (small thermal retention color difference) during the injection molding process of the bromine-based flame-retardant polypropylene composite material and improve the flame-retardant property consistency. In addition, the oxygen index of the bromine-based flame-retardant polypropylene composite material of the present invention is not less than 24, and it has excellent flame-retardant properties. Specific embodiments

[0038] In order to more clearly and completely describe the technical solutions of the present invention, the present invention will be further described in detail below through specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention, and various changes can be made within the scope defined by the claims of the present invention.

[0039] Some of the reagents selected in the examples and comparative examples of the present invention are described as follows:

[0040] Polypropylene resin 1#: Wanhua, EP548R, with a melt flow rate of 30 g / 10 min at 230°C and 2.16 kg.

[0041] Polypropylene resin 2#: CNOOC and Shell, EP300M, with a melt flow rate of 9 g / 10 min at 230°C and 2.16 kg.

[0042] Polypropylene resin 3#: Qilu Petrochemical, SP179, with a melt flow rate of 10 g / 10 min at 230°C and 2.16 kg.

[0043] Brominated flame retardant 1#: Octabromoether, commercially available;

[0044] Brominated flame retardant 2#: Methyl octabromoether, commercially available;

[0045] Flame retardant synergist: Antimony trioxide, commercially available;

[0046] Aluminum stearate: Commercially available;

[0047] Magnesium stearate: Commercially available;

[0048] Potassium stearate: Commercially available;

[0049] Aluminum hydroxide: Commercially available;

[0050] Tris(nonylphenyl) phosphite: Commercially available;

[0051] Tris(2,4-di-tert-butylphenyl) phosphite: Commercially available;

[0052] Bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite: Commercially available;

[0053] Other additive 1#: Antioxidant, antioxidant 1010, commercially available;

[0054] Other additive 2#: Lubricant, ethylene bisstearamide, commercially available.

[0055] Unless otherwise specified, each component (such as the flame retardant synergist) selected in each parallel example and comparative example is the same commercially available product.

[0056] The brominated flame retardant polypropylene composites of each example and comparative example of the present invention are prepared through the following process: Weigh each component according to the formula and mix them evenly, then feed them into the main feeding port of the twin-screw extruder, melt blend, and extrude and pelletize to obtain the brominated flame retardant polypropylene composite.

[0057] Among them, the temperature of the first zone of the twin-screw extruder is 120 °C, the temperature of the second zone is 160 °C, the temperature of the third zone is 170 °C, the temperature of the fourth zone is 170 °C, the temperature of the fifth zone is 180 °C, the temperature of the sixth zone is 180 °C, the temperature of the seventh zone is 180 °C, the temperature of the eighth zone is 170 °C, and the temperature of the ninth zone is 170 °C; the screw speed of the twin-screw extruder is 400 revolutions per minute.

[0058] The performance test methods and standards of the brominated flame retardant polypropylene composites of each example and comparative example of the present invention are as follows:

[0059] (1) Flame retardancy consistency: The vertical burning grade is evaluated according to the standard of UL94 flame retardant grade, and 10 burning specimens are tested; when all specimens reach V-2, it indicates good flame retardancy consistency, which is recorded as "good"; when at least one specimen cannot reach V-2, it indicates poor flame retardancy consistency, which is recorded as "poor";

[0060] (2) Oxygen index: Tested according to the standard of 《GB / T 2406.2 - 2009》;

[0061] (3) Heat retention color difference: The color difference between the injection - molded sample of the composite material after melting and staying for 1 min at 190°C in the injection - molding machine and the normal injection - molded sample (after melting at 190°C). If the color difference does not exceed 0.5, it is considered that the yellow streaks at the injection gate are effectively improved. The test equipment is the Color Eye 7000A type color difference meter.

[0062] Examples 1 - 8

[0063] Examples 1 - 8 provide a series of brominated flame - retardant polypropylene composite materials, and the weight parts of each component in the formula are shown in Table 1.

[0064] Table 1 Formulas of Examples 1 - 8

[0065]

[0066]

[0067] Comparative Examples 1 - 6

[0068] Comparative Examples 1 - 6 provide a series of brominated flame - retardant polypropylene composite materials, and the weight parts of each component in the formula are shown in Table 2.

[0069] Table 2 Formulas of Comparative Examples 1 - 6

[0070]

[0071] The performance test results of the brominated flame - retardant polypropylene composite materials in each example and comparative example according to the method mentioned above are shown in Table 3.

[0072] Table 3 Performance test results of the brominated flame - retardant polypropylene composite materials in each example and comparative example

[0073]

[0074]

[0075] It can be seen from Table 3 that the oxygen indexes of the brominated flame - retardant polypropylene composite materials prepared in Examples 1 - 8 of the present invention are not less than 24, the consistency of the flame - retardant performance is good, and the color differences in the heat retention color difference test are all less than 0.5, indicating that the yellow streaks at the injection gate of the brominated flame - retardant polypropylene composite materials of the present invention are improved, the consistency of the flame - retardant performance is good, and they have excellent flame - retardant performance.

[0076] Comparative Examples 1 to 3 are cases where aluminum stearate and tris(nonylphenol) phosphite are not added, only aluminum stearate is added, and only tris(nonylphenol) phosphite is added, respectively. The flame retardant properties of the brominated flame retardant polypropylene composites prepared are poor in consistency, have a large color difference in heat retention, and the oxygen index is smaller than that of Example 1, and the yellow streaks at the injection molding gate cannot be effectively improved.

[0077] In Comparative Examples 4 and 5, tris(nonylphenol) phosphite was replaced with other phosphites. The flame retardant properties of the brominated flame retardant polypropylene composites prepared are poor in consistency, have a large color difference in heat retention, and the oxygen index is smaller than that of Example 1, and the yellow streaks at the injection molding gate cannot be effectively improved.

[0078] In Comparative Example 6, aluminum stearate was replaced with aluminum hydroxide. The flame retardant properties of the brominated flame retardant polypropylene composites prepared are poor in consistency, have a large color difference in heat retention, and the oxygen index is smaller than that of Example 1, and the yellow streaks at the injection molding gate cannot be effectively improved.

[0079] Obviously, the above-mentioned embodiments of the present invention are merely examples for clearly explaining the present invention, and are not intended to limit the embodiments 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. It is not necessary and impossible to enumerate all the embodiments here. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the claims of the present invention.

Claims

1. A brominated flame-retardant polypropylene composite material, characterized in that: The invention comprises the following components in parts by weight: 87-92.5 parts of polypropylene resin, 5-8 parts of brominated flame retardant, 2-4 parts of flame retardant synergist, 0.3-0.6 parts of stearate and 0.3-0.6 parts of tris(nonylphenol)phosphite.

2. The brominated flame-retardant polypropylene composite material according to claim 1, characterized in that: The stearate is at least one of aluminum stearate, magnesium stearate or potassium stearate.

3. The brominated flame-retardant polypropylene composite material according to claim 2, characterized in that: The stearate is aluminum stearate.

4. The brominated flame-retardant polypropylene composite material according to claim 1, characterized in that: The flame retardant synergist is an antimony-containing compound.

5. The brominated flame-retardant polypropylene composite material according to claim 1, characterized in that: The melt flow rate of the polypropylene resin at 230° C. and 2.16 kg is 1 to 70 g / 10 min.

6. The brominated flame-retardant polypropylene composite material according to claim 1, characterized in that: The brominated flame retardant is at least one of octabromoether, methyl octabromoether or octabromotrimethylether.

7. The brominated flame-retardant polypropylene composite material according to claim 1, characterized in that: The brominated flame-retardant polypropylene composite material further comprises the following components in parts by weight: 0.5 to 1 part of other additives.

8. The brominated flame-retardant polypropylene composite material according to claim 1, characterized in that: The other auxiliary agent is at least one of an antioxidant and a lubricant.

9. The method for preparing the brominated flame-retardant polypropylene composite material according to any one of claims 1 to 8, characterized in that: The method comprises the following steps: weighing and mixing the components according to the formula, performing melt blending, and extruding and granulating to obtain the bromine-based flame-retardant polypropylene composite material.

10. Use of the brominated flame-retardant polypropylene composite material according to any one of claims 1 to 8 in the preparation of household items, electronic components, household appliances, gardening equipment, medical technology equipment, motor vehicle components or body parts.

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