阅读说明：本技术 一种无卤阻燃硅烷自交联电缆料及其制备方法 (Halogen-free flame-retardant silane self-crosslinking cable material and preparation method thereof ) 是由 王立春 曹华 于 2019-11-18 设计创作，主要内容包括：本发明公开了一种无卤阻燃硅烷自交联电缆料及其制备方法,包括以下重量份数配比的原料：100份PE、0～200份POE、0～5份交联剂、0～2份引发剂、0～300份阻燃剂、0～20份增容剂、0～5份脱水剂、0～3份交联催化剂和0～2份抗氧剂。本发明通过添加磷/氮类膨胀型阻燃剂,降低了阻燃剂的添加量,避免了对交联催化剂的吸附,使材料保持了较好的强度和柔性。采用有机酸为脱水剂,有机锡为交联催化剂,通过控制电缆料加工温度和硅烷接枝反应温度相互匹配,及后续电缆挤出温度和有机酸脱水温度互相匹配,成功实现了阻燃聚烯烃的自动硅烷交联,避免了电缆水煮或水蒸气辅助的交联工艺。(The invention discloses a halogen-free flame-retardant silane self-crosslinking cable material and a preparation method thereof, wherein the halogen-free flame-retardant silane self-crosslinking cable material comprises the following raw materials in parts by weight: 100 parts of PE, 0-200 parts of POE, 0-5 parts of a cross-linking agent, 0-2 parts of an initiator, 0-300 parts of a flame retardant, 0-20 parts of a compatibilizer, 0-5 parts of a dehydrating agent, 0-3 parts of a cross-linking catalyst and 0-2 parts of an antioxidant. The invention reduces the addition of the flame retardant by adding the phosphorus/nitrogen intumescent flame retardant, avoids the adsorption of a crosslinking catalyst and ensures that the material keeps better strength and flexibility. Organic acid is used as a dehydrating agent, organic tin is used as a crosslinking catalyst, the processing temperature of the cable material and the silane grafting reaction temperature are controlled to be matched with each other, and the subsequent cable extrusion temperature and the organic acid dehydration temperature are matched with each other, so that the automatic silane crosslinking of the flame-retardant polyolefin is successfully realized, and the cable water boiling or steam assisted crosslinking process is avoided.)

1. The halogen-free flame-retardant silane self-crosslinking cable material is characterized by comprising the following raw materials in parts by weight:

100 parts of PE, 0-200 parts of POE, 0-5 parts of a cross-linking agent, 0-2 parts of an initiator, 0-300 parts of a flame retardant, 0-20 parts of a compatibilizer, 0-5 parts of a dehydrating agent, 0-3 parts of a cross-linking catalyst and 0-2 parts of an antioxidant.

2. The halogen-free flame retardant silane self-crosslinking cable material as claimed in claim 1, wherein the PE is Linear Low Density Polyethylene (LLDPE), such as SP0510, SP0540, SP1510, SP1520, SP1540, etc. produced by Mitsui corporation of Japan; the tensile strength is more than or equal to 12MPa, and the melt index is 1.0-20.0 g/10 min.

3. The halogen-free flame-retardant silane self-crosslinking cable material of claim 1, wherein the POE is a copolymer elastomer of ethylene and octene, such as POE8100, POE8150, POE8180, POE8200, etc.; the density of the powder is 0.85-0.88 g/cm³The melting point is 50-80 ℃, the Shore hardness is 60A-90A, and the melt index is 0.5-20 g/10 min.

4. The halogen-free flame-retardant silane self-crosslinking cable material according to claim 1, wherein the crosslinking agent is vinyl silane such as vinyltrimethoxysilane, vinyltriethoxysilane, vinylmethyldiethoxysilane, vinyldimethylethoxysilane, vinyltris (2-methoxyethoxy) silane.

5. The cable material of claim 1, wherein the initiator is an organic peroxide initiator, such as dicumyl peroxide (DCP), Benzoyl Peroxide (BPO), t-butyl peroxybenzoate, diisopropyl peroxydicarbonate, and cyclohexanone peroxide.

6. The halogen-free flame-retardant silane self-crosslinking cable material according to claim 1, wherein the flame retardant is a phosphorus/nitrogen intumescent flame retardant, such as FP-2100J, FP-2200, FP-2200S, manufactured by Ediko, Japan.

7. The halogen-free flame-retardant silane self-crosslinking cable material as claimed in claim 1, wherein the compatibilizer is maleic anhydride grafted polyethylene (PE-MAH) or maleic anhydride grafted POE (POE-MAH), and the grafting ratio of the MAH is greater than or equal to 1.0%.

8. The halogen-free flame-retardant silane self-crosslinking cable material as claimed in claim 1, wherein the dehydrating agent is an organic acid capable of generating water by heating, such as anhydrous citric acid, oxalic acid, stearic acid, etc.; or salts containing water of crystallization: such as CoCl₂·6H₂O、SnCl₂·2H₂O、Ca(SO₄)·2H₂O、Cu(SO₄)·5H₂O、Na₂(CO₃)·10H₂O, and the like.

9. The halogen-free flame retardant silane self-crosslinking cable material of claim 1, wherein the crosslinking catalyst is an organic tin compound capable of catalyzing silanol condensation reaction, such as dibutyltin dilaurate (DBTDL), stannous octoate, dibutyltin diacetate, dibutyltin bis (dodecylthio), etc.

10. The halogen-free flame-retardant silane self-crosslinking cable material as claimed in claim 1, wherein the antioxidant is antioxidant 330, 300, 1010, DSTP or 264, etc.

11. The preparation method of the halogen-free flame retardant silane self-crosslinking cable material according to any one of claims 1 to 10, characterized by comprising the following steps:

s1, firstly adding 100 parts of PE, 0-200 parts of POE, 0-5 parts of cross-linking agent and 0-2 parts of initiator into an internal mixer, internally mixing for 3-5 min at the temperature of 155 ℃, and carrying out grafting reaction;

and S2, sequentially adding 0-300 parts of flame retardant, 0-20 parts of compatibilizer, 0-5 parts of dehydrating agent, 0-3 parts of crosslinking catalyst and 0-2 parts of antioxidant into an internal mixer, carrying out internal mixing for 5-10 min, transferring into a double-screw extruder, and carrying out extrusion, cooling and particle cutting to obtain the halogen-free flame-retardant silane self-crosslinking cable material.

Technical Field

The invention relates to the technical field of cable material preparation, in particular to a halogen-free flame-retardant silane self-crosslinking cable material and a preparation method thereof.

Background

Crosslinked polyolefins are widely used in cable insulation and jacket materials. In general, the crosslinking methods of polyolefins such as polyethylene and POE mainly include: peroxide chemical crosslinking, silane crosslinking, irradiation or ultraviolet crosslinking, and the like. Silane crosslinking has more advantages due to the characteristics of less equipment required by production and processing, less investment, low requirement on environment and the like, and is generally concerned in the industry. In the current production process, either the one-step method or the two-step method, silane crosslinking usually needs to be realized by subsequent water boiling or steam.

The halogen-free flame-retardant silane crosslinking not only affects the mechanical strength and flexibility of polyolefin due to the need of adding a large amount of traditional magnesium-aluminum salt flame retardants, but also reduces the crosslinking degree and deteriorates the heat resistance due to the adsorption of part of crosslinking catalysts. Therefore, the preparation of the silane self-crosslinking halogen-free flame-retardant polyolefin cable material is a difficult problem in the cable industry.

Disclosure of Invention

Technical problem to be solved

Aiming at the defects of the prior art, the invention provides a halogen-free flame-retardant silane self-crosslinking cable material and a preparation method thereof, which have the advantages of high flexibility, high strength, good flame retardance, good temperature resistance, simple process and the like and solve the problems in the background art.

(II) technical scheme

In order to realize the purposes of high flexibility, high strength, good flame retardance, good temperature resistance and simple process, the invention provides the following technical scheme:

the halogen-free flame-retardant silane self-crosslinking cable material comprises the following raw materials in parts by weight:

100 parts of PE, 0-200 parts of POE, 0-5 parts of a cross-linking agent, 0-2 parts of an initiator, 0-300 parts of a flame retardant, 0-20 parts of a compatibilizer, 0-5 parts of a dehydrating agent, 0-3 parts of a cross-linking catalyst and 0-2 parts of an antioxidant.

Preferably, the PE is a Linear Low Density Polyethylene (LLDPE), such as SP0510, SP0540, SP1510, SP1520, SP1540, and the like, manufactured by mitsui, japan; the tensile strength is more than or equal to 12MPa, and the melt index is 1.0-20.0 g/10 min; further, the LLDPE is SP0540 in grade, the Shore hardness is 49D, the melt index is 3.8g/10min (190 ℃/2.16 kg), the tensile strength is more than or equal to 16MPa, and the elongation at break is more than or equal to 500%.

Preferably, the POE is an ethylene-octene copolymer elastomer, such as POE8100, POE8150, POE8180, POE8200 and the like; the density is 0.85-0.88 g/cm3, the melting point is 50-80 ℃, the Shore hardness is 60A-90A, and the melt index is 0.5-20 g/10 min; further, the POE is POE8100, the Shore hardness is 73A/22D, the melt index is 1.0g/10min (190 ℃/2.16 kg), the tensile strength is 9.8MPa, and the elongation at break is 810%.

Preferably, the crosslinking agent is a vinyl silane, such as vinyltrimethoxysilane, vinyltriethoxysilane, vinylmethyldiethoxysilane, vinyldimethylethoxysilane, vinyltris (2-methoxyethoxy) silane; further, the cross-linking agent is vinyl triethoxysilane, the relative density of the cross-linking agent is 0.90, the boiling point of the cross-linking agent is 160-161 ℃, the refractive index of the cross-linking agent is 1.39, and the cross-linking agent is colorless and transparent liquid.

Preferably, the initiator is an organic peroxide initiator, such as dicumyl peroxide (DCP), Benzoyl Peroxide (BPO), tert-butyl peroxybenzoate, diisopropyl peroxydicarbonate, cyclohexanone peroxide; further, the initiator is DCP, the relative density of the initiator is 1.08, the melting point of the initiator is 41-42 ℃, the decomposition temperature is 120-125 ℃, the refractive index of the initiator is 1.53, and the initiator is white crystals in appearance.

Preferably, the flame retardant is a phosphorus/nitrogen type intumescent flame retardant such as FP-2100J, FP-2200, FP-2200S and the like manufactured by Idiaceae, Japan; further, the flame retardant is an intumescent flame retardant with the brand number FP-2200, the phosphorus content is 16-20%, the nitrogen content is 19-23%, the flame retardant is white powder in appearance, and the thermal decomposition temperature is more than or equal to 270 ℃.

Preferably, the compatibilizer is maleic anhydride grafted polyethylene (PE-MAH) or maleic anhydride grafted POE (POE-MAH), and the grafting rate of the MAH is more than or equal to 1.0 percent; further, the compatibilizer is POE-MAH, such as grafted products 1801, 1803 and the like produced by Exxon Mobil, and the grafting rate is more than or equal to 1.5 percent.

Preferably, the dehydrating agent is an organic acid which can generate water by heating, such as anhydrous citric acid, oxalic acid, stearic acid, and the like; or salts containing water of crystallization: such as CoCl2 & 6H2O, SnCl2 & 2H2O, Ca (SO4) & 2H2O, Cu (SO4) & 5H2O, Na2(CO3) & 10H2O, etc.; furthermore, the dehydrating agent is a binary composition of anhydrous citric acid and stearic acid, the anhydrous citric acid starts to decompose at about 175 ℃ to generate water, and the stearic acid mainly reacts with ethanol generated after the silane is hydrolyzed to generate water.

Preferably, the crosslinking catalyst is an organic tin compound capable of catalyzing silanol condensation reaction, such as dibutyltin dilaurate (DBTDL), stannous octoate, dibutyltin diacetate, dibutyltin bis (dodecylthio) and the like; furthermore, the crosslinking catalyst is DBTDL, the refractive index of the crosslinking catalyst is 1.46, the relative density of the crosslinking catalyst is 1.05, the boiling point of the crosslinking catalyst is not less than 200 ℃, the tin content of the crosslinking catalyst is 17-19%, the water content of the crosslinking catalyst is not more than 0.3%, and the crosslinking catalyst is light yellow transparent liquid.

Preferably, the antioxidant is antioxidant 330, 300, 1010, DSTP or 264 and the like; furthermore, the antioxidant is antioxidant 330, the purity is more than or equal to 99 percent, the melting point is more than or equal to 242 ℃, and the appearance is white crystal powder.

The invention also provides a preparation method of the halogen-free flame-retardant silane self-crosslinking cable material, which comprises the following steps:

s1, firstly adding 100 parts of PE, 0-200 parts of POE, 0-5 parts of cross-linking agent and 0-2 parts of initiator into an internal mixer, internally mixing for 3-5 min at the temperature of 155 ℃, and carrying out grafting reaction;

and S2, sequentially adding 0-300 parts of flame retardant, 0-20 parts of compatibilizer, 0-5 parts of dehydrating agent, 0-3 parts of crosslinking catalyst and 0-2 parts of antioxidant into an internal mixer, carrying out internal mixing for 5-10 min, transferring into a double-screw extruder, and carrying out extrusion, cooling and particle cutting to obtain the halogen-free flame-retardant silane self-crosslinking cable material.

(III) advantageous effects

Compared with the prior art, the invention provides a halogen-free flame-retardant silane self-crosslinking cable material and a preparation method thereof, and the halogen-free flame-retardant silane self-crosslinking cable material has the following beneficial effects:

1. according to the halogen-free flame-retardant silane self-crosslinking cable material and the preparation method thereof, the binary composition of LLDPE and POE is used as a base material, the strength and flexibility of the material are considered, and POE-MAH is added as a compatibilizer, so that good compatibility of a flame retardant is ensured. Compared with the traditional magnesium/aluminum salt flame retardant, the phosphorus/nitrogen intumescent flame retardant has the advantages that the addition amount is greatly reduced, the adsorption of silane and organic tin is avoided, and the effective crosslinking, mechanical and heat-resistant properties of the material are ensured.

2. According to the halogen-free flame-retardant silane self-crosslinking cable material and the preparation method thereof, the organic acid is used as the dehydrating agent, the organic tin is used as the crosslinking catalyst, the mutual matching of the processing temperature of the cable material and the silane grafting reaction temperature is controlled, and the mutual matching of the subsequent cable extrusion temperature and the organic acid dehydration temperature is controlled, so that the automatic silane crosslinking of the flame-retardant polyolefin is successfully realized, the water boiling or steam auxiliary crosslinking link of the cable is avoided, and the production and processing technology is simplified.

Detailed Description

The present invention will be further illustrated with reference to the following specific examples.

The grades and physical properties of the raw materials used in the following examples and comparative examples of the present invention are shown in Table 1:

TABLE 1

The following examples and comparative examples of the present invention all adopt the same processing technology, i.e., after the materials are banburied, the materials are granulated by an extruder to prepare a halogen-free flame retardant silane self-crosslinking cable material (the formula and the composition of the cable material are shown in table 2). And then, extruding the cable at 175-180 ℃, dehydrating the citric acid, and carrying out catalysis of organic tin to realize automatic crosslinking of the extruded cable. Relevant tests in the invention all adopt the method to extrude the halogen-free flame-retardant silane self-crosslinking polyethylene medium-voltage cable, and the sampling is carried out after the cable is placed for 2 hours.

The halogen-free flame-retardant silane self-crosslinking cable material obtained in the following examples and comparative examples has single-strand burning and bundled burning experiments of cables, and is tested by using GB/T12666.1-2008 standard. The flame retardant performance is respectively measured by adopting an oxygen index meter and a vertical combustion meter, the oxygen index is measured according to the national standard GB 2406.2-2009, and the vertical combustion is measured according to the UL94 standard. The hardness was measured by a Shore durometer and the value at 1 second was read. The mechanical property of the composite material is tested according to the standard of GB/T2951.11-2008, and the composite material is stretched on a universal electronic tensile machine at the stretching speed of 250 mm/min. The thermal elongation performance is according to the national standard of GB/T2951-2008, the experimental temperature is 200 +/-3 ℃, after the load time is 15min, the test piece after thermal elongation is taken out from an aging box, cooled to the room temperature, and the permanent deformation rate of the test piece is measured and calculated.

TABLE 2

The test results and properties of the above examples 1 to 3 and comparative examples 4 to 7 of the present invention are shown in Table 3:

TABLE 3