CN102765736B

CN102765736B - Production method of magnesium hydrate fire retardant

Info

Publication number: CN102765736B
Application number: CN201210286797.7A
Authority: CN
Inventors: 李志洲; 刘军海
Original assignee: Shaanxi University of Technology
Current assignee: Shaanxi University of Technology
Priority date: 2012-08-13
Filing date: 2012-08-13
Publication date: 2014-04-16
Anticipated expiration: 2032-08-13
Also published as: CN102765736A

Abstract

The invention discloses a production method of magnesium hydrate fire retardant. Bischofite is dissolved, initial concentration of Mg2+ is 0.15mol/L, ammonia water is added according to 1:3 of the ratio of amount of substance of the Mg2+ to the ammonia water; a compound surface active agent is added in an aging device, addition quantity is 5-7% of initial mixed liquor by volume, heating and sublimating are carried out for 20 minutes, absolute ethyl alcohol is added to enable ethanol volume ratio to achieve 40-50%, and sublimating is carried out for 30-40 minutes; the mixed liquor is pressed by a compressor to enter a spray dryer, the nozzle hole diameter is 0.2mm, simultaneously hot air with the temperature of 130-160 DEG C is led in for drying, air quantity is 22-30m<3>/h, modified magnesium hydrate fire retardant is obtained, and the product particle size is 20-100nm. Physicochemical parameters of products produced by the production method are that oil factor per 100g of the products is 0.24-0.26mL, activation index of the products is 87.5-89.6%, and sedimentation time is 228-235minutes.

Description

A kind of flame retardant of magnesium hydroxide production method

Technical field

What the present invention relates to is a kind of flame retardant of magnesium hydroxide production method.

Background technology

Along with developing rapidly of Macromolecular materials industry, the macromolecular materials such as plastics, synthetic rubber, synthon are more and more widely used in the fields such as building materials, household electrical appliances, electronics, automobile, chemical industry, traffic.But the inflammableness problem of macromolecular material causes people's attention day by day.According to statistics, to have more than 30% be that dense smoke and the toxic gas of material production causes to the fatalities in fire.Thereby for flammable product, except institute adds the flame retardant effect of fire retardant, low toxicity, low cigarette are also the requisite indexs of fire retardant, this is also one of most active problem in fire retardant research field in recent years.

Flame retardant of magnesium hydroxide is domestic a kind of flame retardant products of developing in recent years, can be widely used in the plastic industries such as polypropylene, polyethylene, polyvinyl chloride, high impact styrene and ABS.Novel inorganic Mg (OH) ₂that fire retardant has is nontoxic, smokeless, antiacid, non-corrosiveness, decomposition temperature are high, the efficient advantage such as short base material incarbonization and be extensively subject to people's concern.With respect to organic halogen flame retardant, by magnesium hydroxide, as the superpolymer of fire retardant, be a kind of green engineering material, be applicable to more multipair fire retardant and require strict place to use.

But the superfine Mg (OH) of preparation conventionally ₂, particularly nanometer Mg (OH) ₂, thering is the speciality such as the distinctive small-size effect of nano material, quantum size effect, surface effects, macroscopic quantum effect, microparticle surfaces has very strong polarity and wetting ability, and crystal grain trends towards secondary agglomeration; Meanwhile, due to Mg (OH) ₂the combustion heat be less than the combustion heat of macromolecular material, reach desirable flame retardant effect, just must have larger loading level; In addition, due to Mg (OH) ₂thermal expansivity different from the thermal expansivity of polymer materials, when machine-shaping, it expands with heat and contract with cold and causes two-phase interface place easily to form microcrack; Mg (OH) again ₂the product that fire retardant and high polymer material make after forming process, long-time place can with damp atmosphere in CO ₂there is chemical reaction, seriously limited its application.Therefore rational surface modification is to improving Mg (OH) ₂use properties and to widen its Application Areas very important, even essential.Mg (OH) ₂the method of modification can be divided into surface chemical modification, apply modification, precipitin reaction modification, micro encapsulation modification, surface grafting method and mechanochemical modification etc., Mg (OH) at present ₂the most frequently used method of modifying is surface chemical modification method.

Summary of the invention

Technical problem to be solved by this invention is to provide a kind of flame retardant of magnesium hydroxide production method for the deficiencies in the prior art.

Technical scheme of the present invention is as follows:

A kind of flame retardant of magnesium hydroxide production method, dissolves bischofite Mg ²⁺starting point concentration 0.15mol/L, according to Mg ²⁺with the ratio of ammoniacal liquor amount of substance be to add ammoniacal liquor at 1: 3; Then at digestion tank, add compound surfactant, its add-on is the 5-7% of former mixeding liquid volume per-cent, heating Chen Hua 20min, after add dehydrated alcohol, make ethanol volume ratio reach 40-50%, then Chen Hua 30-40min; Mixed solution enters spray-dryer through compressor pressurization, and nozzle bore 0.2mm, passes into 130-160 ℃ of warm air simultaneously and be dried, air quantity 22-30m ³/ h, obtains modified magnesium hydroxide flame retardant agent, and product granularity is 20-100nm.

Described method, described compound surfactant is that sodium laurylsulfonate, both molar ratios of sodium stearate mix gained at 1: 1.

Product physical and chemical parameter: the oil-absorption(number) of every 100g product is 0.24-0.26mL; The activation index of product is 87.5-89.6%; Settling time 228-235min.

Accompanying drawing explanation

Fig. 1 is process flow sheet of the present invention;

1 mixes digestion tank, 2 compressors, 3 spray-dryers, 4 hoppers, 5 tornado dust collector;

A MgCl ₂, B NH ₃h ₂o, C compound surfactant, D warm air, E waste gas, F tail dirt is collected.

Embodiment

Below in conjunction with specific embodiment, the present invention is described in detail.

The design has changed traditional batch formula and has produced fire retardant technique, with surface chemical modification principle, adopts continous way flow process to prepare flame retardant of magnesium hydroxide, and its continous way flow process as shown in Figure 1.

1. raw water chloromagnesite (MgCl ₂6H ₂o), NH ₃h ₂o, dehydrated alcohol (99.9%), sodium laurylsulfonate, sodium stearate;

2. operating parameters: magnesium chloride is 1: 3 with the ratio of the amount of substance of ammoniacal liquor, (Mg ²⁺starting point concentration 0.15mol/L); Compound surfactant (sodium laurylsulfonate, sodium stearate molar ratio 1: 1) the add-on 5-7% (V/V) of sodium laurylsulfonate and sodium stearate; 99.9% (dehydrated alcohol) amount of alcohol added (being the 40-50% of mixeding liquid volume in digestion tank), digestion time 30-40min; Atomizing pressure 2Mpa; Hot air temperature 130-160 ℃; Nozzle bore 0.2mm.

Process description:

Bischofite is dissolved, and is to add ammoniacal liquor at 1: 3 according to the ratio of amount of substance; Add the compound surfactant that in digestion tank, mixeding liquid volume per-cent is 5-7%, heating Chen Hua 20min, after add dehydrated alcohol, make ethanol volume ratio reach 40-50%, then Chen Hua 30-40min; Mixed solution enters spray-dryer through compressor pressurization, and nozzle bore 0.2mm, passes into 130-160 ℃ of warm air simultaneously and be dried, air quantity 22-30m ³/ h, obtains modified magnesium hydroxide flame retardant agent, and product granularity is 20-100nm; The tail gas that moisture eliminator is discharged separates through cyclonic separator, collects tail dirt, and tail gas (80 ℃) can be used as after the termite utilization of digestion tank emptying.In flow process, design two digestion tanks, finish in operation when a digestion tank solution spray is dry, another is changed by valve control, proceeds, and makes flow process be able to serialization.

Should be understood that, for those of ordinary skills, can be improved according to the above description or convert, and all these improvement and conversion all should belong to the protection domain of claims of the present invention.

Claims

1. a flame retardant of magnesium hydroxide production method, is characterized in that, bischofite is dissolved to Mg ²⁺starting point concentration 0.15mol/L, according to Mg ²⁺with the ratio of ammoniacal liquor amount of substance be to add ammoniacal liquor at 1: 3; Then at digestion tank, add compound surfactant, its add-on is the 5-7% of former mixeding liquid volume per-cent, adds thermal aging 20min, after add dehydrated alcohol, make ethanol volume ratio reach 40-50%, then ageing 30-40min; Mixed solution enters spray-dryer through compressor pressurization, and nozzle bore 0.2mm, passes into 130-160 ℃ of warm air simultaneously and be dried, air quantity 22-30m ³/ h, obtains modified magnesium hydroxide flame retardant agent, and product granularity is 20-100nm; Described compound surfactant is that sodium laurylsulfonate, both molar ratios of sodium stearate mix gained at 1: 1.