WO2022135271A1 - Ultra-soft b1-level low-smoke halogen-free flame-retardant sheath material and preparation method therefor - Google Patents

Abstract

Provided are an ultra-soft B1-level low-smoke halogen-free flame-retardant sheath material and a preparation method therefor. The sheath material comprises the following components in parts by weight: 15 to 35 parts of an ethylene-methyl acrylate copolymer; 15 to 35 parts of an ethylene-octylene copolymer; 25 to 40 parts of a hydrogenated styrene-butadiene block copolymer; 5 to 15 parts of a rubber filling oil; 3 to 8 parts of SEBS grafted maleic anhydride; 3 to 8 parts of polyphenyl ether; 120 to 170 parts of magnesium hydroxide; 10 to 35 parts of aluminum hypophosphite; 3 to 8 parts of a smoke suppressant; 1 to 3 parts of an antioxidant; and 1 to 3 parts of a lubricant, wherein the content of styrene in the hydrogenated styrene-butadiene block copolymer is 20 to 40 wt%, and the aluminum hypophosphite is subjected to a coating treatment. The maximum value of the Shore A hardness of the sheath material is 79 A, which satisfies B1 level flame retardance; the light transmittance of the finished product is larger than or equal to 60%; and the tensile strength and elongation at break thereof meet the standard. Same can be applied to an environment in need of an ultra-soft cable sheath.

Description

A kind of ultra-soft B1 grade low-smoke halogen-free flame retardant sheath material and preparation method thereof technical field

The invention relates to the field of cable sheathing materials, and more particularly, to an ultra-soft B1-grade low-smoke halogen-free flame-retardant sheathing material and a preparation method thereof.

Background technique

GB/T 31247 Class B1 flame retardant cables are mainly used in densely populated places such as airports, stations, rail transit, and large buildings. Compared with GB/T 19666 and GB/T 17651, GB/T 31247 B1 flame retardant has higher requirements for the heat release and smoke release properties of the sheath material, which is difficult to meet with traditional sheath materials. Halogen-free flame retardant cable material is filled with a large amount of metal hydroxide, which makes the material generally hard, and the Shore A hardness is very large. It also does not meet the GB/T 31247 B1 standard.

For complex cable lines inside buildings, or for scenarios that require high flexibility, a sheath material with relatively high flexibility is required. For example, some cables have limited laying space, such as offshore platforms. In order to save space and facilitate laying, This requires the cable to have a smaller bend radius. In order to obtain a small bending radius for the cable, on the one hand, the cable structure should be reasonably designed and easy to bend; The soft feature imparted to the cable facilitates laying during construction. Materials with high hardness are not conducive to construction.

However, for materials with low hardness, the material is easy to soften and has poor temperature resistance. When burning in bundles (20 minutes of burning for high-grade bundled combustion), if the charring efficiency is not enough, the flammable mechanism inside the cable cannot be protected in time, which is easy to cause The temperature of the box is too high (over 100°C), causing the sheath to fall off, resulting in failure of the flame retardant. Therefore, it is very difficult for the soft sheath material to reach the B1 level.

Chinese patent (CN104672743A) discloses an oil-resistant and corrosion-resistant super-soft cable sheath material and a preparation method thereof. Although it satisfies the super-soft performance, the flame retardant can not meet the B1-level flame retardant performance.

SUMMARY OF THE INVENTION

The present invention provides a super soft B1-level low-smoke halogen-free flame-retardant sheath material in order to overcome the above-mentioned defect of the prior art that both softness and B1-level flame retardancy cannot be satisfied at the same time.

Another object of the present invention is to provide a preparation method of the ultra-soft B1-grade low-smoke halogen-free flame retardant sheath material.

Another object of the present invention is to provide the ultra-soft B1-grade low-smoke halogen-free flame-retardant cable jacket.

For achieving the above object, the technical scheme adopted in the present invention is:

An ultra-soft B1 grade low-smoke halogen-free flame retardant sheath material, comprising the following components calculated by weight:

The content of styrene in the hydrogenated styrene-butadiene block copolymer is 20-40 wt%;

The aluminum hypophosphite is coated.

The present invention firstly adopts hydrogenated styrene-butadiene block copolymer with a styrene content of 20-40 wt% and rubber filler oil to reduce the hardness of the resin and greatly improves the softness of the material; wherein, hydrogenated styrene-butadiene- The styrene content of the butadiene block copolymer has excellent softness when the content of styrene is 20-40%. After fully mixing with the rubber filler oil, the distribution of the matrix resin is more uniform, and the softness is further improved; at the same time, the use of The excellent compatibility of polyphenylene ether, SEBS grafted maleic anhydride and hydrogenated styrene-butadiene block copolymer greatly improves the mechanical properties of the material; the coated aluminum hypophosphite, magnesium hydroxide and The compounding of smoke suppressant, on the one hand, reduces the content of magnesium hydroxide and improves the softness; The combination of magnesium hydroxide and aluminum hypophosphite can obtain a good flame retardant carbonization effect. Aluminum hypophosphite is an acidic substance, and magnesium hydroxide is a weakly alkaline substance. The aluminum hypophosphite is coated to effectively avoid the reaction with magnesium hydroxide, resulting in flame retardant failure.

The aluminum hypophosphite is coated with melamine resin.

Preferably, the content of methacrylic acid in the ethylene-methyl acrylate copolymer is 18-36 wt %. When the content of methacrylic acid is 18-36wt%, the resin has better tensile strength.

Preferably, the molecular weight of the hydrogenated styrene-butadiene block copolymer is greater than or equal to 250,000. Increase the tensile strength of hydrogenated styrene-butadiene block copolymers.

The rubber filler oil is naphthenic rubber oil and paraffin-based rubber oil.

Preferably, the content of styrene in the SEBS-grafted maleic anhydride is 20-40 wt%. When the styrene content is within 20-40wt%, it has better softness.

Preferably, the graft ratio of the SEBS-grafted maleic anhydride is greater than or equal to 0.8%.

The determination of the grafting ratio can be performed by a conventional method, for example, an acid-base titration method.

Preferably, the average particle size of the aluminum hypophosphite is less than or equal to 50 μm. When the average particle size is less than or equal to 50 μm, it has better flame retardant performance.

Preferably, the average particle size of the magnesium hydroxide is less than or equal to 1.5 μm. When the average particle size is less than or equal to 1.5 μm, it has better flame retardant performance.

The surface of the magnesium hydroxide is coated with 3-aminopropyltriethoxysilane, and the coating rate is more than 80%

Preferably, the smoke suppressant is a mixture of nano-montmorillonite, ammonium octamolybdate and zinc borate, wherein, by weight, 5-25 parts of nano-montmorillonite; 35-55 parts of ammonium octamolybdate; boric acid Zinc is 20 to 40 parts.

The molecular weight of the polyphenylene ether is 20000-60000, it is powder PPO, and the average particle size is between 20-100 μm.

The melt index of the ethylene-octene copolymer is 0.5-3 g/10min and the density is 0.87-0.895 g/cm ³ when tested at 190° C. under a load of 2.16 Kg.

The present invention also provides a preparation method of the ultra-soft B1-grade low-smoke halogen-free flame-retardant sheathing material, comprising the following steps:

S1. Pre-mix hydrogenated styrene-butadiene block copolymer and rubber filler oil in proportion, let stand, then mix ethylene-octene copolymer and polyphenylene ether, extrude through twin-screw extruder, make Granulated, dried.

The length-diameter ratio of the twin-screw extruder is L/D=48, and the set temperature of each zone is 160-200°C.

S2. the material after the drying of step S1 and ethylene-methyl acrylate copolymer, SEBS graft maleic anhydride, magnesium hydroxide, aluminum hypophosphite, smoke suppressant, antioxidant, lubricant are put into dense Mixing in a mill, mixing, cooling, discharging and granulation.

The temperature of the internal mixer is 145-160°C. Mixing time is not less than 10min.

The application of the ultra-soft B1-grade low-smoke halogen-free flame-retardant sheath material for preparing cable sheath.

Compared with the prior art, the beneficial effects of the present invention are:

The invention provides an ultra-soft B1 grade low-smoke halogen-free flame retardant cable sheath material, which adopts hydrogenated styrene-butadiene block copolymer with styrene content of 20-40 wt%, rubber filler oil and SEBS grafted horse The acid anhydride is blended to reduce the hardness of the resin and greatly improve the softness of the material. The maximum value of Shore A hardness of the sheath material is 79A, which meets B1 level flame retardancy, the light transmittance of the finished product is greater than or equal to 60%, the tensile strength and elongation at break meet the standard, and it can be applied to cables that require ultra-soft in a sheathed environment.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below, but the embodiments of the present invention are not limited thereto.

The reagents, methods and equipment used in the present invention, unless otherwise specified, are conventional reagents, methods and equipment in the technical field.

The raw materials used in the following examples and comparative examples are as follows:

Ethylene-methyl acrylate copolymer A: the methacrylic acid content is 18wt%, and the TC 121 Molding brand of ExxonMobil is used;

Ethylene-methyl acrylate copolymer B: the methacrylic acid content is 20wt%, and the 20MA08 brand of French Arkema is used;

Ethylene-methyl acrylate copolymer C: the content of methacrylic acid is 24wt%, and the 24MA005 brand of French Arkema is used;

Ethylene-methyl acrylate copolymer D: the content of methacrylic acid is 10wt%, and the SP1402 grade of Westlake Chemical in the United States is used;

Ethylene-methyl acrylate copolymer E: the content of methacrylic acid is 31wt%, and the 29MA003 brand of French Arkema is used;

Hydrogenated styrene-butadiene block copolymer A: the styrene content is 20wt%, the molecular weight is 300,000, and a commercially available product is used;

Hydrogenated styrene-butadiene block copolymer B1: the styrene content is 28wt%, the molecular weight is 300,000, and a commercially available product is used;

Hydrogenated styrene-butadiene block copolymer C: the styrene content is 32wt%, the molecular weight is 300,000, and a commercially available product is used;

Hydrogenated styrene-butadiene block copolymer D: the styrene content is 18wt%, the molecular weight is 300,000, and a commercially available product is used;

Hydrogenated styrene-butadiene block copolymer E: the styrene content is 35wt%, the molecular weight is 300,000, and a commercially available product is used;

Hydrogenated styrene-butadiene block copolymer B2: the styrene content is 28wt%, the molecular weight is 250,000, and a commercially available product is used;

Hydrogenated styrene-butadiene block copolymer B3: the styrene content is 28wt%, the molecular weight is 150,000, and a commercially available product is used;

Hydrogenated styrene-butadiene block copolymer B4: the styrene content is 28wt%, the molecular weight is 350,000, and a commercially available product is used;

Hydrogenated styrene-butadiene block copolymer B5: the styrene content is 28wt%, the molecular weight is 450,000, and a commercially available product is used;

Rubber filler A: KN4006 grade of PetroChina Karamay;

Rubber filler oil B: Maoming Petrochemical 32# white oil;

SEBS grafted maleic anhydride A: styrene content is 20wt%, molecular weight is 300,000, and grafting rate is 1%;

SEBS grafted maleic anhydride B: styrene content of 28wt%, molecular weight of 300,000, grafting rate of 1%;

SEBS grafted maleic anhydride C: styrene content is 33wt%, molecular weight is 300,000, and grafting rate is 1%;

SEBS grafted maleic anhydride D: styrene content is 10wt%, molecular weight is 300,000, and grafting rate is 1%;

SEBS grafted maleic anhydride E: styrene content is 40wt%, molecular weight is 300,000, and grafting rate is 1%;

For the preparation of the SEBS grafted maleic anhydride, a twin-screw with a length-to-diameter ratio of 48:1 is used, the initiator and maleic anhydride are fed in proportion to the side, and the processing temperature of the twin-screw extruder is 175-200° C. . The commercially available molecular weight is 300,000, and SEBS of different styrene content grades is used for melt grafting;

Ethylene-octene copolymer: POE 58750 from Dow Chemical is used, density: 0.870, melting index: 1g/10min under the condition of 190℃*2.16Kg;

Polyphenylene ether: Bluestar Chemical LXR-045 grade;

Magnesium Hydroxide: Magnesium Hydroxide adopts the magnesium hydroxide of Shandong Aifel Company with the grade of F5, and the average particle size is 1.5 μm;

Magnesium hydroxide coating; in a high-speed mixer, heat magnesium hydroxide to 60°C, add 3-aminopropyltriethoxysilane in proportion; mix at high speed for 30 minutes;

Aluminum hypophosphite: Lidao new material grade is M-116H, coated with melamine resin, and the average particle size is 10μm;

Smoke suppressant: 5 parts of nano-montmorillonite; 35 parts of ammonium octamolybdate; 40 parts of zinc borate;

Nano-montmorillonite was purchased from: Zhejiang Fenghong Co., Ltd. brand name is DK4;

Ammonium octamolybdate was purchased from: ammonium octamolybdate produced by Hubei Xinhongli Chemical Industry;

Zinc borate was purchased from: ZB-03 of Anhui Yishitong New Materials Co., Ltd.;

Antioxidant: The combination of antioxidant 1010 and antioxidant 168 is used, and the mass ratio is 1:1;

Lubricant: Honeywell polyethylene wax AC-6A is used.

The present invention will be described in detail below in conjunction with examples and comparative examples.

The following examples and comparative examples are all prepared by the following methods to prepare ultra-soft B1-grade low-smoke halogen-free flame retardant sheaths

material, weigh each component according to the weight ratio of table 1～3; Concrete steps are as follows:

S1. Pre-mix hydrogenated styrene-butadiene block copolymer and rubber filler oil in proportion, let stand, then mix ethylene-octene copolymer and polyphenylene ether, extrude through twin-screw extruder, make Granulated, dried.

The length-diameter ratio of the twin-screw extruder is L/D=48, and the set temperature of each zone is 160-200°C.

S2. the material after the drying of step S1 and ethylene-methyl acrylate copolymer, SEBS graft maleic anhydride, magnesium hydroxide, aluminum hypophosphite, smoke suppressant, antioxidant, lubricant are put into dense Mixing in a mill, mixing, cooling, discharging and granulation.

The temperature of the internal mixer is 145-160°C. Mixing time 15min.

Examples 1 to 5

Formulations (parts) of Table 1 Examples 1-5

	Example 1	Example 2	Example 3	Example 4	Example 5
Ethylene-methyl acrylate copolymer B	25	25	25	25	25
Ethylene-Octene Copolymer	25	25	25	25	25
Hydrogenated styrene-butadiene block copolymer B1	30	—	—	—	—
Hydrogenated styrene-butadiene block copolymer B2	—	30	—	—	—
Hydrogenated styrene-butadiene block copolymer B3	—	—	30	—	—
Hydrogenated styrene-butadiene block copolymer B4	—	—	—	30	—
Hydrogenated styrene-butadiene block copolymer B5	—	—	—	—	30
SEBS grafted maleic anhydride B	4	4	4	4	4
Rubber filler oil A	8	8	8	8	8
polyphenylene ether	8	8	8	8	8
magnesium hydroxide	160	160	160	160	160
Aluminum hypophosphite	25	25	25	25	25
smoke suppressant	4	4	4	4	4
Antioxidant	2	2	2	2	2
lubricant	2	2	2	2	2

Examples 6 to 12

Formulations (parts) of Table 2 Examples 6-12

Examples 13 to 19

Formulations (parts) of Table 3 Examples 13-19

Comparative Examples 1 to 6

Table 4 Formulas (parts) of comparative examples 1 to 6

	Comparative Example 1	Comparative Example 2	Comparative Example 3	Comparative Example 4	Comparative Example 5	Comparative Example 6
Ethylene-methyl acrylate copolymer B	25	25	25	25	25	25
Ethylene-Octene Copolymer B	25	25	25	25	25	25
Hydrogenated styrene-butadiene block copolymer B1	—	20	20	20	—	—
Hydrogenated styrene-butadiene block copolymer D	—	—	—	—	20	—
Hydrogenated styrene-butadiene block copolymer E	—	—	—	—	—	20
SEBS grafted maleic anhydride B	4	—	4	4	4	4
Rubber filler oil	8	8	8	—	8	8
polyphenylene ether	8	8	8	8	8	8
magnesium hydroxide	160	160	195	160	160	160
Aluminum hypophosphite	25	25	—	25	25	25
smoke suppressant	4	4	4	4	4	4
Antioxidant	2	2	2	2	2	2

lubricant

2

2

2

2

2

2

The following performance tests were performed on the ultra-soft B1-grade low-smoke halogen-free flame-retardant cable sheathing materials prepared from the above-mentioned Examples 1-19 and Comparative Examples 1-6, and the reference standards and methods for the tests were as follows:

According to the test method of GB/T 32129-2015 low-smoke halogen-free material standard and GB 31247-2014 B1 flame retardant grade standard,

The Shore A hardness test method is tested by the method specified in GB 2411:

The test method of the light transmittance of the finished product adopts the method specified in GB/T 17651-2008:

The test data of each embodiment and comparative example of table 5

From Examples 1 to 5, the higher the molecular weight of the hydrogenated styrene-butadiene block copolymer, the better the mechanical properties of the material.

It can be seen from Examples 1 and 6-8 that the lower the styrene content of the hydrogenated styrene-butadiene block copolymer, the lower the hardness of the material and the better the softness, but the tensile strength also decreases.

From Examples 1 and 9-12, the lower the styrene content of SEBS grafted maleic anhydride, the lower the hardness of the material and the better the softness.

From Examples 1 and 13-16, it can be seen that the higher the methacrylic acid content of the ethylene-methyl acrylate copolymer, the better the smoke density performance of the material, while the mechanics are also improved, and the methacrylic acid content does not affect the softness of the material.

From Examples 17-19, the higher the filler oil content, the lower the hardness of the material, but the mechanical properties of the material will decrease to a certain extent.

From the comparative examples 1 to 6, the hardness of the material is too high without the extended oil or the hydrogenated styrene-butadiene block copolymer; the hydrogenated styrene-butadiene block copolymer is insufficient, and the material hardness is too high; no When the hydrogenated styrene-butadiene block copolymer is grafted with maleic anhydride, the mechanical properties of the material cannot meet the requirements of the national standard; from the comparative example 3, if no aluminum hypophosphite is added, it needs to add more hydrogen Magnesium oxide can not meet the B1 level, and its Shore A hardness is relatively large.

Obviously, the above-mentioned embodiments of the present invention are only examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those of ordinary skill in the art, changes or modifications in other different forms can also be made on the basis of the above description. There is no need and cannot be exhaustive of all implementations here. Any modifications, equivalent replacements and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the claims of the present invention.

Claims (10)

1. An ultra-soft B1-level low-smoke halogen-free flame-retardant sheathing material, characterized in that it comprises the following components calculated by weight:

   

   The content of styrene in the hydrogenated styrene-butadiene block copolymer is 20-40 wt%;

   The aluminum hypophosphite is coated.
2. The ultra-soft B1 grade low-smoke halogen-free flame retardant sheath material according to claim 1, wherein the methacrylic acid content in the ethylene-methyl acrylate copolymer is 18-36 wt%.
3. The ultra-soft B1 grade low-smoke halogen-free flame-retardant sheathing material according to claim 1, wherein the molecular weight of the hydrogenated styrene-butadiene block copolymer is greater than or equal to 250,000.
4. The ultra-soft B1 grade low-smoke halogen-free flame-retardant sheath material according to claim 1, wherein the content of styrene in the SEBS-grafted maleic anhydride is 20-40 wt%.
5. The ultra-soft B1 grade low-smoke halogen-free flame-retardant sheathing material according to claim 1, wherein the graft ratio of the SEBS-grafted maleic anhydride is greater than or equal to 0.8%.
6. The ultra-soft B1 grade low-smoke halogen-free flame-retardant sheath material according to claim 1, wherein the average particle size of the aluminum hypophosphite is less than or equal to 50 μm.
7. The supersoft B1 grade low-smoke halogen-free flame retardant sheath material according to claim 1, wherein the average particle size of the magnesium hydroxide is less than or equal to 1.5 μm.
8. The supersoft B1 grade low-smoke halogen-free flame retardant sheathing material according to claim 1, wherein the smoke suppressant is a mixture of nano-montmorillonite, ammonium octamolybdate and zinc borate, wherein, by weight , nano-montmorillonite 5-25 points; ammonium octamolybdate is 35-55 parts; zinc borate is 20-40 parts.
9. According to the preparation method of the ultra-soft B1-level low-smoke halogen-free flame-retardant sheath material according to any one of claims 1 to 8, it is characterized in that, comprising the following steps:

   S1. Pre-mix hydrogenated styrene-butadiene block copolymer and rubber filler oil in proportion, let stand, then mix ethylene-octene copolymer and polyphenylene ether, extrude through twin-screw extruder, make Granulated, dried.

   S2. the material after the drying of step S1 and ethylene-methyl acrylate copolymer, SEBS graft maleic anhydride, magnesium hydroxide, aluminum hypophosphite, smoke suppressant, antioxidant, lubricant are put into dense Mixing, discharging and granulating in the mill.
10. A cable sheath, comprising the ultra-soft B1-grade low-smoke halogen-free flame-retardant sheath material according to any one of claims 1 to 8.