CN112080074B - Flame-retardant polypropylene composition and preparation method and application thereof - Google Patents

Abstract

The invention discloses a flame-retardant polypropylene composition and a preparation method and application thereof, wherein the flame-retardant polypropylene composition comprises the following components: 70-90 parts of polypropylene resin; 2-8 parts of a brominated flame retardant; 1-3 parts of antimony trioxide; 0.2-1 part of high-temperature initiator; 0.5-5 parts of hydrotalcite; 0.5-5 parts of inorganic zinc compound. According to the invention, a brominated flame retardant, antimony trioxide, a high-temperature initiator, hydrotalcite and an inorganic zinc compound are synergistically used, and a small amount of flame retardant (2-8 parts) is added, so that the flame-retardant polypropylene composition can reach a vertical combustion V-2 level and a horizontal combustion A-0 level, the oxygen index is more than 25%, the smoke density is less than or equal to 50, and the odor level is less than or equal to 3.5.

Description

Flame-retardant polypropylene composition and preparation method and application thereof

Technical Field

The invention belongs to the field of high polymer materials, and particularly relates to a flame-retardant polypropylene composition, and a preparation method and application thereof.

Background

Polypropylene is one of the most widely used general plastics due to its excellent comprehensive properties, good cost performance and wider processing and forming conditions. The polypropylene is a typical flammable material, the limiting oxygen index of the polypropylene is 17-18%, the polypropylene is extremely easy to burn and cannot be self-extinguished after being ignited, and the polypropylene material needs to be subjected to flame retardant modification along with the gradual increase of the safety requirement of the material.

The flame retardant for polypropylene is mainly divided into an environment-friendly brominated flame retardant and a halogen-free flame retardant, in order to meet the requirement of non-halogenation, the flame retardant containing phosphorus, nitrogen or a compound system of phosphorus and nitrogen is required to be added in the existing flame-retardant modified polypropylene material, but the halogen-free flame retardant system has the defects of large addition amount, low flame-retardant efficiency, poor physical properties, high water absorption and the like, and has great limitation in wide application. The environment-friendly bromine-containing flame retardant is still the main flame retardant of polypropylene resin, and the bromine-containing flame retardant has the advantages of high flame retardant efficiency, small influence on physical properties and the like, but has the defects of high smoke density, high toxicity, poor heat resistance, easy precipitation and the like during combustion.

In recent years, the application demand of materials in downstream industries is continuously increased, and more products and safety regulations expect the materials to have good flame retardant efficiency, lower smoke density and excellent physical properties. For example, in the transportation industry standard JT/T1095-2016, it is clear that the interior materials of passenger cars must meet the hardness indexes in the aspects of horizontal combustion, vertical combustion, oxygen index and smoke density grade, so that the common non-flame-retardant modified materials are difficult to meet the standard requirements. It is also stated explicitly in the standard that for plastic materials for seats, requirements must be met for horizontal burning velocity of less than or equal to 50mm/min, vertical burning velocity of less than or equal to 100mm/min, and oxygen index of greater than or equal to 24%, whereas passenger car manufacturers have higher requirements than the standard requirements, and in addition to the items required by the standard, lower smoke density (< 50) and odor grade (<3.5 grade), and excellent impact properties (>45kJ/m2), are required. The existing common bromine-antimony system has the defects of over-high smoke density and insufficient toughness of the halogen-free intumescent flame retardant system, and the comprehensive properties are difficult to be considered and are difficult to satisfy.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention mainly aims to provide a flame-retardant polypropylene composition which has the advantages of good flame-retardant efficiency, high oxygen index, low odor, low smoke release and the like.

Another object of the present invention is to provide a method for preparing the flame retardant polypropylene composition.

The invention is realized by the following technical scheme:

the flame-retardant polypropylene composition comprises the following components in parts by weight:

70-90 parts of polypropylene resin;

2-8 parts of a brominated flame retardant;

1-3 parts of antimony trioxide;

0.2-1 part of high-temperature initiator;

0.5-5 parts of hydrotalcite;

0.5-5 parts of inorganic zinc compound.

As a further preferable technical scheme, the flame-retardant polypropylene composition comprises the following components in parts by weight:

70-90 parts of polypropylene resin;

3-5 parts of a brominated flame retardant;

1-2 parts of antimony trioxide;

0.2-0.5 part of high-temperature initiator;

1-3 parts of hydrotalcite;

1-3 parts of inorganic zinc compound.

Preferably, the polypropylene resin is selected from one or a mixture of two of homo-polypropylene and co-polypropylene.

From the viewpoint of rationalization of performance, the addition amount of the brominated flame retardant is 2-8 parts, and preferably 3-5 parts. When the addition amount is too small, the flame retardant effect is correspondingly poor, and when the addition amount is less than 2 parts, the flame retardant stability is reduced; when the amount is too high, there is no significant difference in flame retardancy, but odor and smoke density increase.

Preferably, the bromine-based flame retardant is an organic bromine-based flame retardant, specifically selected from one or a mixture of several of decabromodiphenylethane, tris (tribromoneopentyl) phosphate, tris (2, 3-dibromopropyl) isocyanurate, tetrabromobisphenol a bis (2, 3-dibromopropyl) ether and tetrabromobisphenol S bis (2, 3-dibromopropyl) ether, and from the viewpoint of flame retardant efficiency and odor, preferably selected from one or a mixture of several of tris (tribromoneopentyl) phosphate, tris (2, 3-dibromopropyl) isocyanurate and tetrabromobisphenol a bis (2, 3-dibromopropyl) ether.

Preferably, the purity of the antimony trioxide is more than 99.0%, preferably more than 99.8%; of said antimony trioxide

The D50 particle size is 5mm or less, preferably 1mm or less.

Preferably, the high-temperature initiator is one or a mixture of two of poly (1, 4-diisopropylbenzene) and 2, 3-dimethyl-2, 3-diphenylbutane.

Preferably, the hydrotalcite has a D50 particle size of 5mm or less, preferably 1mm or less.

Preferably, the inorganic zinc compound is one or a mixture of zinc borate, zinc stannate, zinc aluminate and zinc oxide.

According to actual performance requirements, the flame-retardant polypropylene composition further comprises 0-15 parts of elastomer, 0-1 part of antioxidant and 0-1 part of processing aid in parts by weight.

Preferably, the elastomer is an ethylene and alpha olefin copolymer, more preferably one or a mixture of two of an ethylene and butene copolymer or an ethylene and octene copolymer; the content of the elastomer is preferably 5 to 10 parts from the viewpoint of rationalization of properties. When the addition amount of the elastomer is too small, the toughness of the material is correspondingly poor; when the amount of the elastomer added is too high, the flame retardant property of the material is lowered.

Preferably, the antioxidant is selected from one or a mixture of phenol, phosphite ester, bivalent sulfur or sterically hindered amine antioxidants; wherein the phenolic antioxidant comprises antioxidant 264, antioxidant 1010, antioxidant 1076, antioxidant SP, antioxidant 2246, antioxidant CA, antioxidant 330, Irganox1890 or antioxidant 3114, the phosphite comprises antioxidant TNP, antioxidant ODP, antioxidant 168, Irganox1093 or Irganox1222, the bivalent sulfur antioxidant comprises dilaurate thiodipropionate (DLTP) and distearate thiodipropionate (DSTP), and the hindered amine antioxidant comprises LS-744, LS-770, GW-540 or Flamstab NOR 116.

Preferably, the processing aid is one or more selected from low molecular weight lipids, metal soaps, stearic acid complex esters and amides; wherein the low molecular lipid is solid paraffin, liquid paraffin or low molecular polyolefin wax, the metal soap is calcium stearate, magnesium stearate, zinc stearate or barium stearate, the stearic acid composite ester is ethylene glycol stearate, glyceryl stearate or pentaerythritol stearate, and the amide is erucyl amide, methylene bis stearamide or N, N-ethylene bis stearamide.

The invention also provides a preparation method of the flame-retardant polypropylene composition, which comprises the following steps:

after weighing the components in proportion, uniformly mixing the components through a high-speed mixer, then carrying out melt extrusion and granulation through a double-screw extruder at the temperature of 180 ℃ and 200 ℃, and drying to obtain the flame-retardant polypropylene composition.

The invention also provides application of the flame-retardant polypropylene composition in interior decorations of a passenger car. The flame-retardant polypropylene composition prepared by the invention has excellent flame-retardant performance and lower smoke density and odor grade, can be prepared into various interior products of passenger cars according to different purposes, and is particularly suitable for seat products of passenger cars.

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

(1) the brominated flame retardant, the antimony trioxide, the high-temperature initiator, the hydrotalcite and the inorganic zinc compound are used in a synergistic manner, and a small amount of flame retardant (2-8 parts) is added, so that the flame-retardant polypropylene composition can reach a vertical combustion V-2 level and a horizontal combustion A-0 level, the oxygen index is more than 25 percent, the smoke density is less than or equal to 50, and the odor level is less than or equal to 3.5, and the prepared flame-retardant polypropylene composition has excellent flame retardant property and lower smoke density and odor level, can be prepared into various interior products of passenger cars according to different purposes, is particularly suitable for seat products of the passenger cars, and has excellent industrial application prospect;

(2) according to the invention, the high-temperature initiator is used, so that the flame retardant efficiency can be effectively improved, the consumption of the brominated flame retardant is reduced, the hydrotalcite can effectively adsorb bromine-containing micromolecular substances while the excellent flame retardant performance is achieved, the odor grade is reduced, the smoke density grade of the brominated flame retardant can be effectively reduced by the inorganic zinc compound, and the three components are combined to achieve a remarkable synergistic effect, so that all performances are further improved;

(3) in the flame-retardant polypropylene composition provided by the invention, the raw materials are all common materials sold in the market, no special chemicals are used, the preparation process is simple and easy, the requirement on equipment is low, and the comprehensive cost performance of the product is higher.

Detailed Description

The present invention will be described in detail with reference to specific examples. The following examples will assist those skilled in the art in further understanding the invention, but are not intended to limit the invention in any way. It should be noted that variations and modifications can be made by persons skilled in the art without departing from the spirit of the invention. All falling within the scope of the present invention.

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

copolymerized polypropylene: PP SP179, china petrochemicals;

elastomer: ethylene and octene copolymer POE 8137, dow chemical;

brominated flame retardants: tetrabromobisphenol S bis (2, 3-dibromopropyl) ether, danxia chemical industry;

tetrabromobisphenol a bis (2, 3-dibromopropyl) ether, israel chemical group;

tris (2, 3-dibromopropyl) isocyanurate, available from hong Kong seawater chemical Co., Ltd;

tris (tribromoneopentyl) phosphate, israel chemical group;

inorganic zinc compound: zinc borate, denaton chemical ltd;

zinc oxide, commercially available;

antimony trioxide 1: the purity is 99.8 percent, the grain diameter of D50 is less than 1mm, and the tin mine Dianxian antimony industry, Inc.;

antimony trioxide 2: the purity is 99.0 percent, the grain diameter of D50 is less than 5mm, and the D50 is purchased from the market;

hydrotalcite 1: d50 particle size < 1mm, Japan Co-Ltd;

hydrotalcite 2: d50 particle size is less than 5mm, and is commercially available;

high-temperature initiator: 2, 3-dimethyl-2, 3-diphenylbutane: tanzhou Zhufeng Fine chemical Co., Ltd;

antioxidant: antioxidant 1010, Tianjin Lianlong New Material Ltd;

antioxidant 168, Tianjin Lianlong New Material Ltd;

processing aid: calcium stearate, zhongshan huamingtai chemical corporation;

other raw materials, commercially available.

The relevant performance test criteria or methods are as follows:

test method of vertical burning: according to the UL94 standard, the test specimen has a thickness of 2.0 mm;

horizontal burning speed test: according to the test method of GB/T8410, the thickness of the test sample strip is 3.0 mm;

smoke density rating test (SDR): according to the test method of GB/T8627, the thickness of a test sample strip is 6.0 mm;

and (3) oxygen index test: according to the test method of GB/T2406.2, the thickness of the test sample strip is 4.0 mm;

and (3) testing the odor grade: taking 20 g of finished particles, putting the finished particles into a special odor test bottle, baking the finished particles at 80 ℃ for 2 hours, taking out the finished particles, cooling the finished particles to 60 ℃, opening the cover to smell the odor of the particles, and grading.

Examples 1 to 11 and comparative examples 1 to 5:

weighing the components according to the proportion shown in the table 1, uniformly mixing the components through a high-speed mixer, then performing melt extrusion and granulation at the temperature of 180-200 ℃ through a double-screw extruder, and drying to obtain the flame-retardant polypropylene composition; the flame retardant polypropylene compositions prepared in examples and comparative examples were tested for vertical flame retardancy, horizontal flame retardancy, oxygen index, and smoke density, and the results are shown in table 1.

TABLE 1 examples and comparative examples the specific proportions of the components and the performance results (in parts by weight)

	Example 1	Example 2	Example 3	Example 4	Example 5	Example 6	Example 7	Example 8
									Polypropylene copolymer	80	80	80	80	80	80	80	80
POE	5	5	5	5	5	5		5
									Tris (2, 3-dibromopropyl) isocyanurate	3				3	3	3	6
Tetrabromobisphenol A bis (2, 3-dibromopropyl) ether			3
									Tris (tribromoneopentyl) phosphate				3
Tetrabromobisphenol S bis (2, 3-dibromopropyl) ether		3
									Antimony trioxide 1	1	1	1	1	1	1	1	2
High temperature initiators	0.3	0.3	0.3	0.3	0.3	0.3	0.3	0.3
									Hydrotalcite 1	1	1	1	1	2	1	1	1
Zinc borate	1	1	1	1	1	2	1	1
									Antioxidant 1010	0.1	0.1	0.1	0.1	0.1	0.1	0.1	0.1
Antioxidant 168	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2
									Calcium stearate	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2
Vertical burning (UL-94, 2.0 mm)	V-2	V-2	V-2	V-2	V-2	V-2	V-2	V-2
									Horizontal combustion	A-0	A-0	A-0	A-0	A-0	A-0	A-0	A-0
Smoke density rating	45	49	48	39	42	39	46	50
									Oxygen index (%)	26.5	25.1	26.7	25.4	26.9	27	26.4	27.3
Odor grade	3.2	3.4	3.3	3.2	3	3.4	3.2	3.5

Continuing with Table 1:

	example 9	Example 10	Example 11	Comparative example 1	Comparative example 2	Comparative example 3	Comparative example 4	Comparative example 5
									Polypropylene copolymer	80	90	74	80	80	80	80	80
POE	5	10	8	5	5	5	5	5
									Tris (2, 3-dibromopropyl) isocyanurate	3		2	3	3	3	3	3
Tris (tribromoneopentyl) phosphate		5
									Antimony trioxide 2	1	1	2	1	1	1	1	1
High temperature initiators	0.3	0.5	0.8		0.3	0.3	0.3
									Hydrotalcite 2	1	2	3			1		1
Zinc borate	1						1	1
									Zinc oxide		2	3
Antioxidant 1010	0.1	0.1	0.1	0.1	0.1	0.1	0.1	0.1
									Antioxidant 168	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2
Calcium stearate	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2
									Vertical burning (UL-94, 2.0 mm)	V-2	V-2	V-2	V-2	V-2	V-2	V-2	V-2
Horizontal combustion	A-0	A-0	A-0	A-0	A-0	A-0	A-0	A-0
									Smoke density rating	48	45	46	71	70	69	68	69
Oxygen index (%)	25.5	26.1	25.7	24.2	24.7	24.6	24.5	24.6
									Odor grade	3.3	3.3	3.4	4.3	4.2	4	3.9	4.2

From a comparison of the examples and comparative examples of table 1, it can be seen that: the invention uses the bromine flame retardant, antimony trioxide, high temperature initiator, hydrotalcite and inorganic zinc compound for synergistic effect, and can realize good flame retardant effect on polypropylene resin by adding a small amount of flame retardant (2-8 parts), thereby achieving vertical combustion V-2 grade, horizontal combustion A-0 grade, oxygen index of more than 25%, smoke density of less than or equal to 50 and odor grade of less than or equal to 3.5 grade. In comparative example 1, the use of a bromine-based flame retardant alone in combination with antimony trioxide is not stable enough in oxygen index and large in smoke density and odor level. In comparative examples 2-5, when the high-temperature initiator, the hydrotalcite and the inorganic zinc compound are used singly or in a pairwise combination manner, the oxygen index is only slightly improved, the improvement range is small, and the smoke density and the odor grade are not obviously improved basically compared with comparative example 1, which shows that the three components have obvious synergistic interaction effect when used together.

Claims (17)

1. The flame-retardant polypropylene composition is characterized by comprising the following components in parts by weight:

70-90 parts of polypropylene resin;

2-8 parts of a brominated flame retardant;

1-3 parts of antimony trioxide;

0.2-1 part of high-temperature initiator;

0.5-5 parts of hydrotalcite;

0.5-5 parts of inorganic zinc compound;

the high-temperature initiator is one or a mixture of two of poly (1, 4-diisopropylbenzene) and 2, 3-dimethyl-2, 3-diphenylbutane.

2. The flame retardant polypropylene composition according to claim 1, comprising the following components in parts by weight:

70-90 parts of polypropylene resin;

3-5 parts of a brominated flame retardant;

1-2 parts of antimony trioxide;

0.2-0.5 part of high-temperature initiator;

1-3 parts of hydrotalcite;

1-3 parts of inorganic zinc compound.

3. A flame retardant polypropylene composition according to claim 1 or 2, wherein the polypropylene resin is selected from homo polypropylene or co-polypropylene or a mixture of both.

4. A flame retardant polypropylene composition according to claim 1 or 2, wherein the brominated flame retardant is an organic brominated flame retardant.

5. A flame retardant polypropylene composition according to claim 4, wherein the brominated flame retardant is selected from one or a mixture of decabromodiphenylethane, tris (tribromoneopentyl) phosphate, tris (2, 3-dibromopropyl) isocyanurate, tetrabromobisphenol A bis (2, 3-dibromopropyl) ether, tetrabromobisphenol S bis (2, 3-dibromopropyl) ether.

6. A flame retardant polypropylene composition according to claim 5, wherein the brominated flame retardant is one or a mixture of tris (tribromoneopentyl) phosphate, tris (2, 3-dibromopropyl) isocyanurate or tetrabromobisphenol A bis (2, 3-dibromopropyl) ether.

7. A flame retardant polypropylene composition according to claim 1 or 2, wherein the purity of the antimony trioxide is above 99.0%; the D50 particle size of antimony trioxide is below 5 um.

8. The flame retardant polypropylene composition according to claim 7, wherein the purity of said antimony trioxide is above 99.8%; the D50 particle size of the antimony trioxide is below 1 um.

9. The flame retardant polypropylene composition according to claim 1 or 2, wherein the hydrotalcite has a D50 particle size of 5um or less.

10. The flame retardant polypropylene composition according to claim 9, wherein the hydrotalcite has a D50 particle size of 1um or less.

11. A fire retardant polypropylene composition according to claim 1 or 2, wherein the inorganic zinc compound is selected from one or more of zinc borate, zinc stannate, zinc aluminate, and zinc oxide.

12. The flame retardant polypropylene composition according to claim 1, further comprising 0-15 parts by weight of an elastomer, 0-1 part by weight of an antioxidant, and 0-1 part by weight of a processing aid.

13. The flame retardant polypropylene composition according to claim 12, wherein the elastomer is an ethylene and alpha olefin copolymer, and the content of the elastomer is 5 to 10 parts.

14. The flame retardant polypropylene composition according to claim 13, wherein the elastomer is one or a mixture of ethylene and butene copolymer or ethylene and octene copolymer.

15. The flame retardant polypropylene composition according to claim 12, wherein the antioxidant is selected from one or a mixture of phenolic, phosphite, bivalent sulfur or sterically hindered amine antioxidants; the processing aid is selected from one or more of low molecular lipid, metal soap, stearic acid composite ester and amide.

16. A method for preparing a flame retardant polypropylene composition according to any of claims 1 to 15, comprising the steps of:

after weighing the components in proportion, uniformly mixing the components through a high-speed mixer, then carrying out melt extrusion and granulation through a double-screw extruder at the temperature of 180 ℃ and 200 ℃, and drying to obtain the flame-retardant polypropylene composition.

17. Use of the flame retardant polypropylene composition according to any one of claims 1 to 15 in a passenger car upholstery, wherein the passenger car upholstery is a passenger car seat.