AU2020102176A4

AU2020102176A4 - The method for preparing a environment-friendly flame retardant water-borne acrylic resin coating with core shell structure

Info

Publication number: AU2020102176A4
Application number: AU2020102176A
Authority: AU
Inventors: Baorong Duan; Yu Gu; Feng Luan; Qiyan Wang; Quanjie Wang; Han Yu
Original assignee: Yantai University
Current assignee: Yantai University
Priority date: 2020-09-08
Filing date: 2020-09-08
Publication date: 2020-11-12
Anticipated expiration: 2028-09-08

Abstract

The invention discloses a method for preparing a environment-friendly flame retardant water borne acrylic resin coating with core shell structure. Firstly, preparing the phosphorus flame retardant, which is used for the preparation of the nuclear layer emulsion. On this basis, preparing the flame retardant environment-friendly water-bome acrylic resin coating with core shell structure. The invention overcomes the defects as follows: As the traditional CP flame retardant will release formaldehyde when in use, and the flame retardancy of acrylate resin is poor, which will produces droplets when it is on fire. The invention enables both the core and shell of the nuclear-shell structure acrylic resin to form relatively dense carbon layers with large surface. Under the condition of polypeptide modification by hydrolysis of leather shavings, the problem can be avoided that the film of acrylic resin coating will produce droplets when it is on fire. The oxygen index, smoke density and flaming combustion time of the prepared waterborne resin coating can be improved, and the droplets can be avoided.

Description

AUSTRALIA

PATENTS ACT 1990

PATENT SPECIFICATION FOR THE INVENTIONENTITLED:

The method for preparing a environment-friendly flame retardant water-borne acrylic resin

coating with core shell structure

The invention is described in the following statement:-

The method for preparing a environment-friendly flame retardant water-borne acrylic

resin coating with core shell structure

TECHNICAL FIELD

The invention relates to a preparation method of a waterborne acrylate resin coating,

in particular to a preparation method of a flame-retardant nuclear-shell environment

friendly waterborne acrylate resin coating.

BACKGROUND

Flame retardants are mainly used in plastics, rubber, textiles and coatings. The world

demand for flame retardants has exceeded 1.2 million tons/year. Flame retardants mainly

include halogen flame retardants, phosphorus flame retardants, inorganic flame retardants

and hundreds of other varieties. Halogen flame retardants are cost-effective, but there are

also a large number of toxic or corrosive gases released such as HX during combustion,

while some halogen flame retardants, such as pentabromodiphenyl ether and

octabromodiphenyl ether are highly toxic and even carcinogenic.

Common inorganic flame retardants include magnesium oxide and aluminum oxide,

which will absorb heat during combustion, thus it reduces the heat. At the same time, water

molecules are released during combustion, which dilutes the oxygen concentration in the

combustion area. Meanwhile, magnesium oxide and aluminum oxide produced in the

combustion process are refractory materials, which cover the surface of combustion products and can slow down the combustion. However, inorganic flame retardants need to be added in large quantities, and it have poor compatibility with organic materials, which easily leads to the decline of mechanical properties of materials.

Most of the organic phosphorus flame retardants have the advantages of low smoke,

non-toxic, low halogen or halogen free, etc., which are in line with the development

direction of flame retardants. The mechanism of the phosphorus additive is that when the

flame retardant is heated, it can produce a cross-linked solid substance or carbonized layer

with a more stable structure. On the one hand, the formation of the carbonized layer can

prevent the polymer from further pyrolysis; On the other hand, it can prevent the internal

thermal decomposition products from entering the gas phase to participate in combustion.

Phosphorus additives mainly act in the condensed phase, and the flame-retardant

mechanism is as follows: Phosphoric acid is formed as dehydrating agent, which

promotes the formation of carbon that reduces the heat conduction from flame to condensed

phase. Phosphoric acid can absorb, as it prevents the oxidation from CO to C02, and

slows down the heating process. @In the condensed phase, a thin glassy or a liquid

protective layer is formed, therefore it reduces oxygen diffusion, heat and material

conduction between gas and solid phases, and it inhibits carbon oxidation process and

reduces the thermal decomposition of phosphorus flame retardants. Phosphorus-based

flame retardants will sequentially produce phosphoric acid metaphosphoric acid,

phosphoric acid and polymetaphosphoric acid. Polymetaphosphoric acid is a stable

compound with strong dehydration that is not easy to volatilize, and it will isolation from

air on the polymer surface. The released water vapor absorbs a large amount of heat, which

causes the flame retardant on the polymer surface to be decomposed and releases volatile phosphorus compounds. Mass spectrometry analysis shows that the concentration of hydrogen atoms is greatly reduced, which indicates that PO-traps H-, that is,

PO-+H- =HPO.

The flame retardant CP (chemical name N-hydroxymethyl-3-dimethoxyphosphoryl

propionamide) is a product of the Swiss company Ciba-Cargill which is introduced in 1965.

The product is a pale yellow or colorless viscous liquid. It is easy to dissolve in water and

has slight formaldehyde smell. And it is widely used in cotton and polyester. However, the

formaldehyde is contained in the processed materials with the product, its application scope

is limited.

The variety of acrylic resins in China is relatively complete, but compared with

foreign advanced counterparts, there is still a certain gap in production scale, process

control and some products with special performance requirements, especially in process

control and quality stability.Therefore, in the next few years, more advanced automatic

control system should be adopted to ensure the consistency of product process control, so

as to further improve the stability of product quality. In particular, to promote the quality

of products to be in line with that of the foreign manufacturers, is the urgent and

fundamental need for the acrylic resin development.

With the increasingly fierce competition in the market, the profit of general acrylic

resin is declining. Under this circumstance, if the profit of acrylic products is to be

increased, the only way is to develop high-performance products, and always do better than

others. Only in this way can we really improve the competitiveness of products in the

market, and promotes the comprehensive benefits of enterprises. Architectural coatings account for the largest proportion of all coatings. China's architectural coatings account for

24% of acrylic coatings, which is at the world's medium level of development. At present,

China's annual output is about 500,000 tons, of which interior walls account for 60%,

exterior walls account for 25%, and others account for 15%.

Although the coatings currently used in China are still of medium and low grade, the

varieties of acrylic coatings in China are relatively complete. Compared with developed

countries, the gap is not in the varieties of coatings, but in raw materials, production

equipment, production technology and production scale. Among them, the enterprises with

larger production scale and higher technical starting point produce products with high

technical content and good quality. Enterprises with larger production scale and higher

technological starting point can produce products with higher technological content and

better quality.

Asia Pacific, Europe, and North America dominated the acrylic resin market in 2013,

with these three regions together accounting for 85% of the market volume and 75% of the

market value. The growth of related industries in developing countries and regions has

significantly boosted the acrylic resin market. China is now the world's largest acrylic resin

consumer and also the largest acrylic resin market. From 2014 to 2018, its compound

annual growth rate will be twice the global average.

The Chinese patent No. 201711085956.6 discloses a "A high flame retardant

waterborne acrylic resin emulsion and high flame retardant coating", wherein the

emulsion is composed of butyl acrylate, methyl methacrylate, acrylic acid, acrylamide,

polyvinyl alcohol, and peroxide. It is made of bioinitiator, buffer, tribromophenyl maleimide, organic amine pH adjuster and water. Its waterproof performance is no more than level 2, and its flame resistance time is more than 25min.

The Chinese patent No. 201610314807.1 discloses "A method for the preparation of

flame retardant, antibacterial and water repellent water-based acrylate resins", which

comprises the following contents: Peeling the green peel of the walnut, then which is

cleaned with water. Drying the walnut in an oven at 4060°C to constant weight,crushing

and sieving it with 60-80 mesh sieve to obtain walnut green peel powder. Weighing walnut

green peel powder and water, and adding add allyl trimethyl ammonium chloride, methyl

4-methoxyacetoacetate, tetrabutylammonium hydroxide, then refluxing and decocting

twice at 80-90 °C. Filtering the decoctions after they are combined together, then which

are concentrated under hypobaric condition. After the concentrated solution becomes paste

with water content of 15% ~ 20% to constant weight, the concentrated solution of walnut

green peel extract can be obtained which is used in acrylate resin.The obtained acrylate

resin has good affinity with human body, good flame retardancy and water resistance, and

its oxygen index is greater than 25.7, and the flame burning time is less than 1.2s.

Nuclear-shell acrylic resin can effectively overcome the defect that the acrylic resin

is sticky when heated and fragile when cooled, so it is one of the main methods of acrylic

resin synthesis at present. The film of traditional acrylic resin coating will produce droplets

when it is on fire, and it will cause much more fire. Moreover, acrylic resin has poor flame

retardancy, so it is necessary to be modified to improve its flame retardancy.

The chromium waste leather shavings come from the flake waste which are produced

when the the blue leather quilt is sliced into one or more layers, or from the scraps which are produced when the shaving machine cuts the leather to the specified standard thickness.

Chromium waste leather scraps are leftovers from the tannery. As it contains chromium, it

is generally considered to be the main source of pollution in the tanning industry.

According to its weight, it accounts for about 60% of the total leather weight. If it cannot

be processed and fully utilized in time, it will cause a large waste of resources and cause

serious pollution to the environment. Leather shavings contain a lot of protein, if it can be

used rationally, it can turn waste into treasure.

To sum up, the film of acrylic resin coating will produce droplets when it is on fire,

which will cause greater fire. In addition, the flame retardancy of acrylic resin is poor.

Chrome leather shavings contain a large amount of protein and polypeptide, if it can be

well recycled, it will play a double role.

SUMMARY

The technical problem to be solved by the invention, is to provide a preparation

method of a flame-retardant nuclear-shell environment-friendly waterborne acrylate resin

coating. Wherein, dimethyl phosphite and acrylamide are modified by urea instead of

traditional formaldehyde, which are matched with stable materials for preparing nuclear

shell acrylate resin, so as to further improve the flame retardancy of acrylic resin.

The technical scheme of the invention is as follows.

The preparation method of flame retardant nuclear-shell environment-friendly

waterbome acrylate resin coating is characterized by the following steps:

Firstly, preparing nuclear layer emulsion: after methacrylic acid, acrylate and initiator

react under emulsifying condition, adding phosphorus flame retardant, polypeptide, tris (2

aminoethyl) amine and stabilizing material for further reaction to obtain nuclear layer

emulsion; Then putting acrylate and initiator into the nuclear layer emulsion respectively,

then adding phosphorus flame retardant, polypeptide, 2,5-Dihydroxyterephthalic Acid and

stabilizing material, then adding crosslinking agent and emulsifier, and the pH value is

adjusted to 7-8, then the flame retardant nuclear-shell waterborne acrylate resin coating

can be obtained;

The stabilizing material is prepared by the reaction of dichloroethyl aluminium,

tetramethylol phosphate sulfate, isobutyryl benzene and dodecyl dimethyl benzyl

ammonium chloride.

The steps of the preparation method is as follows:

(1) Preparation of phosphorus based flame retardant: Putting 40g dimethyl phosphite

into the reaction vessel and 0.5-1.8 g sodium methoxide respectively, and raise the

temperature to 75-85 °C. After the sodium methoxide is dissolved completely, adding 65

g of acrylamide, and the temperature is lowered to 50-70 °C. At this temperature, keeping

stirring for reaction for 2-5h to obtain the intermediate; Adding 0.5-0.6g of maleic

anhydride and 0.1-0.2g of cycloheximide to the intermediate for reaction at 50-70°C for

min, then lowering the temperature to 40-50°C. Then adding 40-54g of urea and stirring

them at 60-70°C for reaction for 1-2h. After which, the temperature is lowered to -5°C,

adding 6-9g of diphosphoryl chloride. at this condition, keeping stirring for 1-2h, and

gradually raise the temperature to 0°C. Adding 4g of water, and the pH value is adjusted to

6.5 by 30% NaOH, then the phosphorus flame retardant can be obtained;

(2) Preparation of the nuclear layer emulsion: Adding the following materials in the

reaction vessel with the following weight ratios: 40-60g of water, 1.1-1.8g of emulsifier,

0.4-2.g of methacrylic acid, which are mixed and stirred uniformly, and raise the

temperature to 30-45 °C, then stirring for reaction for 40min; Adding monomer A, as the

emulsification is carried out for 40-80min; When the temperature is raised to 65°C, the

reflux water begins to be introduced; When the temperature is increased to 80°C, dripping

0.3-0.7g of the initiator lasting for 1-2h. After the addition, carrying out the reaction of

the above materials for 2h, then adding 1.6-3.4g of phosphorus flame retardant which is

obtained in step (1), 2.152.45g of polypeptide and 0.6-0.8g of tris(2-aminoethyl)amine,

which are stirred at 6070°C for reaction for 1-3h. Adding 2.1-2.7g of the stabilizing

material, and carrying out the reaction at 70°C for 1-2h to obtain the nuclear layer emulsion;

(3) Dripping all monomers B and 0.2-0.4g of initiator into the whole nuclear layer

emulsions which is obtained in step (2) at the same time, and the dripping time lasts for 1h.

After the dripping, the mixture is stirred and reacted at 75-85 °C for 1.5h, adding 1.2-3.8g

of phosphorus flame retardant which is obtained in step (1), 3.3-3.5g of polypeptide and

1.2~1.4g of 2,5-dihydroxyterephthalic acid, the mixture is stirred and reacted at 6070°C

for 1-2h. Adding 1.0~1.6g of stabilizing material for reaction at 60 °C for 1h. Adding

0.4-1.2g of crosslinking agent, carrying out the reaction at the temperature of 75 °C for 2h,

then lower the temperature to 50 °C. Adding 0.3g of emulsifier for reaction for 30min, and

adding ammonia water to adjust the pH value to 7-8 to obtain the flame retardant nuclear

shell waterbome acrylate resin coating;

The monomer A is a mixture of 2-4g of butyl acrylate, 3-5g of methyl methacrylate,

3-6g of ethyl acrylate and 2-4g of hydroxyethyl acrylate;

The initiator is any one of ammonium persulfate, potassium persulfate and potassium

hydrogen persulfate;

The preparation of the stable material comprises the following steps: adding 13g of

water into 4.3g of dichloroethyl aluminium, adding 1.1-1.8g of Tetrakis Hydroxymethyl

Phosphonium Sulfate and 0.4-1.4g of Isobutyrophenone, then the mixture is stirred and

reacted for 1-2h at 40-50 °C. Adding 2.1-4.2g of dodecyl dimethyl benzyl ammonium

chloride to further react for 1-2h at 40-60 °C.After drying, the stable material can be

obtained.

The monomer B is a mixture of 1-6 g of butyl acrylate, 3-7 g of methyl methacrylate,

3-5 g of ethyl acrylate, and 2-6 g of hydroxyethyl acrylate.

The crosslinking agent is any one of divinylbenzene, N,N- methylene bisacrylamide

and DSM environment-friendly crosslinking agent CX-100.

The preparation method of the polypeptide comprises the following steps: mixing 50g

of chrome leather shavings, 500g of water, 10-12g of calcium oxide and 0.6-0.8g of

sodium dodecyl benzene sulfonate, which are stirred for 12h as pretreatment. Adding 5

lOg of calcium oxide, raising the temperature to 70-80°C, and stirring the mixture for 5

8h to obtain hydrolyzate. Performing suction filtration for the first time, adding oxalic acid

into the filtered hydrolysate to adjust the pH value of the hydrolysate to be 6.5-7.5,

performing suction filtration again, standing still. After the suction filtrate is stable,

filtering the precipitate, and the suction filtrate is dried until the water content is less than

%, then the polypeptide can be obtained.

The emulsifier is made by mixing sodium dodecyl benzene sulfonate and OP-10

according to the mass ratio of 2: 1.

The positive effects of the invention:

(1) Sodium methanol plays the role of the alkaline catalyst in the preparation of

intermediates, but the used amount of sodium methanol is small, it is difficult to remove

the methanol which is produced by the traditional vacuum distillation at the boiling point.

The invention adopts maleic anhydride and methanol for esterification reaction, and uses

cycloheximide to promote the esterification reaction, which can effectively remove

methanol, and the preparation process of flame retardant is more environmentally friendly.

(2) The flame retardant mechanism of the condensed phase of phosphorous flame

retardants is that the condensed phase forms a thin glassy or liquid protective layer, and the

thickness of which depends on the coordination of phosphorus, carbon and nitrogen. In

the present invention, adopting dimethyl phosphite and diphosphoryl chloride to prepare

phosphorus, using dimethyl phosphite and acrylamide to prepare carbon, and utilizing

acrylamide and urea to provide nitrogen, so as to obtain the phosphorus-based flame

retardant with a relatively thick-glass protective layer. The flame retardant can be used in

water borne coatings. Compared with traditional CP flame retardants, it is more

environmentally friendly and has higher flame retardant efficiency. Carrying out the zero

degree reaction, in order to remove the residual diphosphoryl chloride and to ensure a safer

reaction.

(3) Compared with the traditional phosphorus flame retardant, the phosphorus flame retardant prepared by the present invention has better expansivity. In other words, the flame retardant can form an expansion layer when heated, and the inner part of the expansion layer is surrounded by a large amount of gas. As gas is a poor conductor of heat, which prevents the contact between the fire and the burned object with better flame retardant effect, while traditional phosphorus flame retardants or CP flame retardants do not have such an expansion effect.

(4) In this preparation method, the core and shell layers of acrylate resin are

simultaneously formed into a compact carbon layer, the obtained phosphorus flame

retardant reacts with carboxylic acids of the nuclear layer and the shell layer. The flame

retardant group is grafted onto the chain segment of acrylic resin, which are crosslinked

with crosslinking agent to improve the stability of flame retardancy.

(5) The main drawback of acrylic resin is that when buring, it will produces droplets,

which can cause secondary damage. The present invention adopts polypeptides obtained

by hydrolysis of chromium leather shavings to modify the core and shell of acrylic resin,

and uses tris(2-aminoethyl)amine and 2,5-dihydroxyterephthalic acid to promote the

combination of polypeptides and acrylic resins, so that the polypeptide is uniformly

dispersed on the branches of the resin chain, and the amount of droplets produced by the

combustion of the prepared acrylic resin can be further reduced.

(6) The effect of pretreatment: Collagen can absorb water and swell after pretreatment,

and it is easier to be extracted by hydrolysis, which will lower the thermal contraction

temperature of collagen, so that collagen can be extracted at a lower temperature. Some

non-collagen protein impurities in raw materials can be dissolved in lime lye and removed, thus it can improve the transparency of gelatin. Part of the fat in the raw material reacts with calcium hydroxide to form calcium soap, which is removed.

(7) The function of stabilizing material is to increase the density of carbon layer of

nuclear layer and shell layer, so as to promote the formation of carbon, and prevent them

from producing droplets. When ethylaluminum dichloride is hydrolyzed in water, it is easy

to induce explosive polymerization because of the four hydroxyl groups of

tetrahydroxymethyl phosphonium sulfate. Therefore, isobutyryl benzene is adopted to

inhibit the reaction, and the material is dispersed and intercalated with dodecyl dimethyl

benzyl ammonium chloride to increase the contact area of carbon layer and further improve

the flame retardancy.

(8) According to the invention, the same initiator is used for the reaction in the core

and the shell, so that the test control is convenient.

DESCRIPTION OF THE INVENTION

The invention is further described below with specific examples, scaling, and

technical effect data.

Example 1

(1) Preparation of phosphorus flame retardant: Putting 40g of dimethyl phosphite into

a three-necked flask, then adding 0.5g of sodium methoxide, raising the temperature to

°C. At this point, the sodium methoxide is completely dissolved, adding 65g of

acrylamide, and gradually lowered the temperature to 50°C. The mixture is stirred for reaction for 2h to obtain the intermediate. Adding 0.5g of maleic anhydride and 0.Ig of cycloheximide for reaction at 50°C for 20min, the obtained intermediate is cooled to

°C.Then adding 40g of urea, stirring the mixture for reaction at 60°C for lh. Lowering

the temperature to-5°C, adding 6g of diphosphoryl chloride, stirring the mixture for

reaction for 1h. Then gradually raise the temperature to 0°C, adding 4g of water, removing

the unreacted diphosphoryl chloride, and finally adjust the pH to about 6.5 with 30% NaOH

to obtain the phosphorus flame retardant.

reaction vessel with the following weight ratios: 40g of water, 1.1g of emulsifier(A mixture

of sodium dodecyl benzene sulfonate and OP-10 according to the mass ratio of 2: 1), 0.4g

of methacrylic acid, which are mixed and stirred uniformly, and raise the temperature to

°C, then stirring for reaction for 40min; Adding monomer A, as the emulsification is

carried out for 40min; When the temperature is raised to 65°C, the reflux water begins to

be introduced; When the temperature is increased to 80°C, dripping 5.3g of ammonium

persulfate solution (containing 5g water)lasting for 1h. After the addition, carrying out the

reaction of the mixture for 2h, then adding 1.6g of phosphorus flame retardant which is

obtained in step (1), 2.15g of polypeptide and 0.6g of tris(2-aminoethyl)amine, which are

stirred at 60°C for reaction for 1h. Adding 2.lg of the stabilizing material, and carrying out

the reaction at 70°C for lh to obtain the nuclear layer emulsion.

The monomer A is a mixture of 2 g of butyl acrylate, 3 g of methyl methacrylate, 3 g

of ethyl acrylate, and 2 g of hydroxyethyl acrylate.

(3) Dripping all monomers B and 0.2g of ammonium persulfate (5.2g of initiator aqueous solution) into the whole nuclear layer emulsions which is obtained in step (2) at the same time, and the dripping time lasts for 1h. After the dripping, the mixture is stirred and reacted at 75°C for 1.5h, adding 1.2g of phosphorus flame retardant which is obtained in step (1), 3.3g of polypeptide and 1.2g of 2,5-dihydroxyterephthalic acid, the mixture is stirred and reacted at 60°C for 1h. Adding 1.Og of stabilizing material for reaction at 60 °C for lh. Adding 0.4g of crosslinking agent, carrying out the reaction at the temperature of

°C for 2h, then lower the temperature to 50 °C. Adding 0.3g of emulsifier(A mixture of

sodium dodecyl benzene sulfonate and OP-10 according to the mass ratio of 2: 1) for

reaction for 30min, and adding ammonia water to adjust the pH value to 7-8 to obtain the

flame retardant nuclear-shell waterbome acrylate resin coating;

water into 4.3g of dichloroethyl aluminium, adding 1.1g of Tetrakis Hydroxymethyl

Phosphonium Sulfate and 0.4g of Isobutyrophenone, then the mixture is stirred and reacted

for lh at 40°C. Adding 2.lg of dodecyl dimethyl benzyl ammonium chloride to further

react for 1h at 40°C.After drying, the stable material can be obtained.

The monomer B is a mixture of: 1 g of butyl acrylate, 3 g of methyl methacrylate, 3 g

of ethyl acrylate, and 2 g of hydroxyethyl acrylate.

of chrome leather shavings, 500g of water, lOg of calcium oxide and 0.6g of sodium

dodecyl benzene sulfonate, which are stirred at normal temperature for 12h as pretreatment.

Adding 5g of calcium oxide, raising the temperature to 70°C, and stirring the mixture for

h to obtain hydrolyzate. Performing suction filtration for the first time, adding oxalic acid into the filtered hydrolysate to adjust the pH value of the hydrolysate to be 6.5-7.5, performing suction filtration again,then standing still the mixture. After the suctionfiltrate is stable, filtering the precipitate, and the suction filtrate is dried , then the polypeptide can be obtained.

Example 2

(1) Preparation of phosphorus flame retardant: Putting 40g of dimethyl phosphite

into a three-necked flask, then adding 1.8g of sodium methoxide, raising the temperature

to 85°C. At this point, the sodium methoxide is completely dissolved, adding 85g of

acrylamide, and gradually lowered the temperature to 70°C. The mixture is stirred for

reaction for 5h to obtain the intermediate. Adding 0.6g of maleic anhydride and 0.2g of

cycloheximide for reaction at 70°C for 20min, the obtained intermediate is cooled to

°C.Then adding 54g of urea, stirring the mixture for reaction at 70°C for 2h. Lowering

the temperature to-5°C, adding 9g of diphosphoryl chloride, stirring the mixture for

reaction for 2h. Then gradually raise the temperature to 0°C, adding 4g of water, removing

to obtain the phosphorus flame retardant.

(2) Preparation of the nuclear layer emulsion: Adding the following materials in

the reaction vessel with the following weight ratios: 60g of water, 1.8g of emulsifier(A

mixture of sodium dodecyl benzene sulfonate and OP-10 according to the mass ratio of 2:

1), 2.Og of methacrylic acid, which are mixed and stirred uniformly, and raise the

temperature to 45°C, then stirring for reaction for 40min; Adding monomer A, as the

emulsification is carried out for 80min; When the temperature is raised to 65°C, the reflux water begins to be introduced; When the temperature is increased to 80°C, dripping 0.7g of potassium persulfate (dissolved in 5g of water)lasting for 2h. After the addition, carrying out the reaction of the mixture for 2h, then adding 3.4g of phosphorus flame retardant which is obtained in step (1), 2.45g of polypeptide and 0.8g of tris(2-aminoethyl)amine, which are stirred at 60°C for reaction for 1h. Adding 2.7g of the stabilizing material, and carrying out the reaction at 70°C for 1h to obtain the nuclear layer emulsion.

The monomer A is a mixture of 4 g of butyl acrylate, 5 g of methyl methacrylate, 6 g

of ethyl acrylate, and 4 g of hydroxyethyl acrylate.

(3) Dripping all monomers B and 0.4g of potassium persulfate (dissolved in 5 g of

water) into the whole nuclear layer emulsions which is obtained in step (2) at the same time,

and the dripping time lasts for 1h. After the dripping, the mixture is stirred and reacted at

°C for 1.5h, adding 3.8g of phosphorus flame retardant which is obtained in step (1),

3.5g of polypeptide and 1.4g of 2,5-dihydroxyterephthalic acid, the mixture is stirred and

reacted at 70°C for 2h. Adding 1.6g of stabilizing material for reaction at 60 °C for 1h.

Then adding 1.2g of N,N-methylenebisacrylamide at the temperature of 75 °C for 2h, then

lower the temperature to 50 °C. Adding 0.3g of emulsifier(A mixture of sodium dodecyl

benzene sulfonate and OP-10 according to the mass ratio of 2: 1) for reaction for 30min,

and adding ammonia water to adjust the pH value to 7-8 to obtain the flame retardant

nuclear-shell waterbome acrylate resin coating.

water into 4.3g of dichloroethyl aluminium, adding 1.8g of Tetrakis Hydroxymethyl

Phosphonium Sulfate and 1.4g of Isobutyrophenone, then the mixture is stirred and reacted for lh at 50°C. Adding 4.2g of dodecyl dimethyl benzyl ammonium chloride to further react for 2h at 60°C.After drying, the stable material can be obtained.

The monomer B is a mixture of: 6 g of butyl acrylate, 7 g of methyl methacrylate, 5 g

of ethyl acrylate, and 6 g of hydroxyethyl acrylate.

of chrome leather shavings(from Wendeng Tannery, the content of chromium trioxide is

4%, which is the same as other examples), 500g of water, 12g of calcium oxide and 0.6g

of sodium dodecyl benzene sulfonate, which are stirred at normal temperature for 12h as

pretreatment. Adding lOg of calcium oxide, raising the temperature to 80°C, and stirring

the mixture for 8h to obtain hydrolyzate. Performing suction filtration for the first time,

adding oxalic acid into the filtered hydrolysate to adjust the pH value of the hydrolysate to

be 6.5-7.5, performing suction filtration again,then standing still the mixture. After the

suction filtrate is stable, filtering the precipitate, and the suction filtrate is dried until the

water content is less than 5%, then the polypeptide can be obtained.

Example 3

(1)Preparation of phosphorus flame retardant: Putting 40g of dimethyl phosphite into

a three-necked flask, then adding 1.15g of sodium methoxide, raising the temperature to

°C. At this point, the sodium methoxide is completely dissolved, adding 75g of

acrylamide, and gradually lowered the temperature to 60°C. The mixture is stirred for

reaction for 3.5h to obtain the intermediate. Adding 0.55g of maleic anhydride and 0.15g

of cycloheximide for reaction at 60°C for 20min, the obtained intermediate is cooled to

°C.Then adding 47g of urea, stirring the mixture for reaction at 65°C for 1.5h. Lowering the temperature to-5°C, adding 7.5g of diphosphoryl chloride, stirring the mixture for reaction for 1.5h. Then gradually raise the temperature to 0°C, adding 4g of water, removing the unreacted diphosphoryl chloride, and finally adjust the pH to about 6.5 with

% NaOH to obtain the phosphorus flame retardant.

(2)Preparation of the nuclear layer emulsion: Adding the following materials in the

reaction vessel with the following weight ratios: 50g of water, 1.45g of emulsifier(A

1), 1.2g of methacrylic acid, which are mixed and stirred uniformly, and raise the

temperature to 38°C, then stirring for reaction for 40min; Adding monomer A, as the

emulsification is carried out for 60min; When the temperature is raised to 65°C, the reflux

water begins to be introduced; When the temperature is increased to 80°C, dripping 0.5g

of potassium bisulfate (dissolved in 5g of water)lasting for 1.5h. After the addition,

carrying out the reaction of the mixture for 2h, then adding 2.5g of phosphorus flame

retardant which is obtained in step (1), 2.3g of polypeptide and 0.7g of tris(2

aminoethyl)amine, which are stirred at 65°C for reaction for 2h. Adding 2.4g of the

stabilizing material, and carrying out the reaction at 70°C for 1.5h to obtain the nuclear

layer emulsion.

The monomer A is a mixture of 3 g of butyl acrylate, 4 g of methyl methacrylate, 4.5

g of ethyl acrylate, and 3 g of hydroxyethyl acrylate.

(3)Dripping all monomers B and 0.3g of potassium monopersulfate (dissolved in 5 g

of water) into the whole nuclear layer emulsions which is obtained in step (2) at the same

time, and the dripping time lasts for 1h. After the dripping, the mixture is stirred and reacted at 80°C for 1.5h, adding 2.5g of phosphorus flame retardant which is obtained in step (1),

3.4g of polypeptide and 1.3g of 2,5-dihydroxyterephthalic acid, the mixture is stirred and

reacted at 65°C for 2h. Adding 1.3g of stabilizing material for reaction at 60 °C for 1h.

Then, adding 0.8g of DSM environment-friendly crosslinking agent CX-100 (Shanghai

Kaiyin Chemical Industry), continuing the reaction at 75°C for 2h. Then lowering the

temperature to 50°C, adding 0.3g of emulsifier(A mixture of sodium dodecyl benzene

sulfonate and OP-10 according to the mass ratio of 2: 1) for reaction time for 30min.

Adding ammonia water to adjust the pH value to 7-8, thus the flame retardant nuclear-shell

waterbome acrylate resin coating can be obtained.

water into 4.3g of dichloroethyl aluminium, adding 1.45g of Tetrakis Hydroxymethyl

Phosphonium Sulfate and 0.9g of Isobutyrophenone, then the mixture is stirred and reacted

for 1.5h at 45°C. Adding 3.1g of dodecyl dimethyl benzyl ammonium chloride to further

react for 1.5h at 50°C.After drying, the stable material can be obtained.

The monomer B is a mixture of: 3.5 g of butyl acrylate, 5 g of methyl methacrylate, 4

g of ethyl acrylate, and 4 g of hydroxyethyl acrylate.

of chrome leather shavings, 500g of water, Ig of calcium oxide and 0.7g of sodium

Adding 7.5g of calcium oxide, raising the temperature to 75°C, and stirring the mixture for

6.5h to obtain hydrolyzate. Performing suction filtration for the first time, adding oxalic

acid into the filtered hydrolysate to adjust the pH value of the hydrolysate to be 6.5-7.5, performing suction filtration again,then standing still the mixture. After the suction filtrate is stable, filtering the precipitate, and the suction filtrate is dried, then the polypeptide can be obtained.

Table 1 Experimental phenomena and data on the synthesis of phosphorus flame

retardants at step (1).

Example 1 Example 2 Example 3 Flame retardant CP

Odor of methanol No No No No

Phenomenon of stable No No explosive No explosive material synthesis explosive polymerization polymerization process polymerizat ion

Methanol content/g 0.00011 0.00008 0.00005 No

Methanol No No No 0.05g/L

Formaldehyde is tested by spectrophotometer method (the flame retardant in step 1 is

tested under the same solid content standard by acetylacetone method). It can be seen from

table 1 that there is no explosive polymerization and almost no methanol odor in this

experiment.

Table 2 Experimental phenomena and data of phosphorus flame retardant synthesis in step

(1) (without any of the following substances).

Example 1 Example 2 Example 3

Odor of methanol/No maleic With odor of With odor of With odor of methanol anhydride methanol methanol

Odor of methanol/No With odor of With odor of With odor of methanol cycloheximide methanol methanol

Methanol content/g (No maleic 0.00025 0.00036 0.00042 anhydride)

Methanol content/g (No 0.00045 0.00028 0.00058 cycloheximide)

As can be seen from Table 2, without the above substances, the methanol odor can be

observed and measured in a relatively large amount; Without isobutyryl benzene and

dodecyl dimethyl benzyl ammonium chloride, it will lead to explosive polymerization in

the reaction.

Table 3 Phenomena of stable material synthesis

Phenomena of stable material With explosive No explosive With explosive synthesis/No isobutyryl benzene polymerization polymerization polymerization

Phenomena of stable material No explosive With explosive With explosive synthesis/No dodecyl dimethyl polymerization polymerization polymerization benzyl ammonium chloride

The phenomenon of stable material synthesis can be obeserved from Table 3.

Determination of flame retardant carbon residual ratio and swelling height: weighing

1 g of sample, recording the mass change of the crucible used. Putting the crucible with the

sample into the muffle furnace. Taking out the crucible at 450 °C, determine the height of

the sample at this time and M1(the mass of the crucible after heating).

Table 4 Performance of phosphorus flame retardant in step (1).

Example 1 Example 2 Example 3 Flame Common retardant CP phosphorus flame retardant

Carbon residue rate/% 68.5 67.8 66.4 12.1 11.8

Height of expansion/cm 5.9 4.9 6.8 0.2 1.1

The common phosphorus flame retardant is FRC-1 of Yongju Chemical Raw Material

Company of Lanshan District, Linyi city. It can be seen from Table 3 that the performance

of the flame retardant is better than that of the common flame retardant and the flame

retardant CP.The common phosphorus flame retardant is compared with the environment

with consistent solid content of the example to ensure the accuracy of the experiment.

Table 5 Performance of flame retardant (without any of the following substances).

Example 1 Example 2 Example 3

Carbon residue rate/% (No diphosphoryl 52.4 53.6 48.6 chloride)

Height of expansion/cm (No diphosphoryl 4.9 4.7 6.3 chloride)

It can be seen that, without diphosphoryl chloride, the carbon residual rate and

expansion height decrease.

Table 5 Performance of the film of waterbome nuclear-shell acrylate resin.

Example 1 Example 2 Example 3 Comparative example 1

Oxygen index/% 28.4 28.6 28.8 25.7

Smoke density 4.9 4.7 6.3 22.8

Burning time with 1.2 0.8 1.4 1.3 flame/s

Burning time without 0.1 0.1 0.1 0.1 flame/s

Carbon residue rate at 46.2 47.8 43.9 8.4 350°C/%

Droplets No No No Many

Among them, Comparative Example 1 adopts the finished product prepared in

Example 1 of the Chinese Patent Application No. 201610314807.1 (There exists difference

from the original data in the specification, in order to ensure the test environment is the

same). The acrylic resin emulsion needs to be formed into a film before the test. The test

is conducted under the same conditions in Example 1, Example 2 and Example 3 of the

present invention. It can be seen from Table 5 that the examples of the present invention is

significantly better than Comparative Example 1 in terms of oxygen index, smoke density,

carbon residue rate, and burning droplets, and there is no obvious droplets compared with

the traditional acrylic resin in this experiment.

The reference test method: Both ASTM E 662 and GB 8323-87 specify the smoke

density measurement method, which was developed by National Bureau of Standards

(NBS) (now changed to National Institute of Technology and Standards, NITS), and the

equipment used is a smoke density box.The sample of 7.6cm x 7.6cm x 2.5cm is vertically

fixed in the box of 91cm x 91cm x 63cm, and the heat flow produced by the heater is 25kW

/ m2 . During the test, burning the sample in the box to release the smoke. Measuring the

change of light transmittance of the parallel beam which passes through the smoke.Then

the specific optical density is calculated, that is, the smoke density per unit area of sample

which is diffused in unit volume of smoke box per unit light path length, which is expressed

as Ds.

GB/T5455-1997 "Vertical Method of Textile Combustion Performance Test"

determines the flamed combustion time (after flame time) and flameless combustion time

of the film formed by polyurethane coatings.

The oxygen index is tested by GB/T5454-1997. as the phenomenon of combustion

droplets can only be observed by a team of two people.

The carbon residual rate test method is the same as the flame retardant test method, as

the only difference is that the test temperature of former one is 350 °C.

Table 6 Performance of the film formed by waterborne nuclear-shell acrylate resin (without

any of the substances).

Example 1 Example 2 Example 3

Oxygen index/%(without 25.4 23.6 25.1 stabilizing material) The carbon residual rate at 350 °C 32.1 30.5 28.4

Combustion droplet Some Some Some phenomenon/without stabilizing material

The carbon residual rate at 350 21.5 24.5 18.9 °C/without polypeptide

Combustion droplet Some Some Some phenomenon/without polypeptide

The carbon residual rate at 350 36.4 35.2 32.3 °C/without Tris (2- aminoethyl) amine

Combustion droplet Some Some Some phenomenon/without Tris (2 aminoethyl) amine

The carbon residual rate at 350 26.7 25.3 27.1 °C/without 2,5- dihydroxy terephthalic acid

Combustion droplet Some No Some phenomenon/without 2,5 dihydroxy terephthalic acid

From Table 6, it can be found that without any of the following substances, it will

decrease the carbon residual ratio and oxygen index, and will induce droplets.

The OP-10 described in this invention is the OP-10 emulsifier produced by Shaoxing

County Guocheng Plastic Spraying Co., Ltd. (Chemical purity of other manufacturers can

also be selected).

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. The method of for preparing a environment-friendly flame retardant water-borne

acrylic resin coating with core shell structure is characterized in that it comprises the

following steps:

Firstly, preparing the nuclear layer emulsion: after methacrylic acid, acrylate and

initiator react under emulsifying condition, then putting phosphorus flame retardant,

polypeptide, tris (2- aminoethyl) amine and stabilizing material to continue the reaction to

obtain the nuclear layer emulsion; Then acrylic ester and initiator are placed into the

nuclear layer emulsion respectively. Adding phosphorus flame retardant, polypeptide, 2,5

Dihydroxyterephthalic acid and stabilizing material, then adding crosslinking agent and

emulsifier, and the pH value is adjusted to 7-8, to obtain the flame retardant environment

friendly water-borne acrylic resin coating with core shell structure;

Secondly, the phosphorus flame retardant is prepared by the following steps: using

dimethyl phosphite, sodium methoxide and acrylamide to prepare the intermediate; adding

maleic anhydride and cycloheximide into the intermediate for reaction, then adding urea

for further reaction. Adding diphosphoryl chloride, water, and the pH value is adjusted to

6.5, then the phosphorus flame retardant can be obtained;

Tetrakis Hydroxymethyl Phosphonium Sulphate, isobutyrophenone and Benzalkonium

chloride.

2. The method for preparing the flame retardant environment-friendly water-borne

acrylic resin coating with core shell structure is characterized in that it comprises the following steps:

6.5 by 30% NaOH 6.5, then the phosphorus flame retardant can be obtained;

(3) Dripping all monomers B and 0.2-0.4g initiator into the whole nuclear layer

of phosphorus flame retardant which are all obtained in step (1), 3.3-3.5g of polypeptide

and 1.2~1.4g of 2,5-dihydroxyterephthalic acid, the mixture is stirred and reacted at 6070°C

for 1-2h. Adding 1.0~1.6g of stabilizing material for reaction at 60 °C for lh. Adding

shell waterbome acrylate resin coating;

3-6g of ethyl acrylate and 2-4g of hydroxyethyl acrylate;

obtained.

3. The preparation method of flame retardant nuclear-shell environment-friendly

waterborne acrylate resin coating according to claim 2, wherein the initiator is any one of

ammonium persulfate, potassium persulfate and potassium hydrogen persulfate.

4. 4. The preparation method of flame retardant nuclear-shell environment-friendly waterbome acrylate resin coating according to claim 2, characterized in that the crosslinking agent is any one of divinylbenzene, N,N- methylene bisacrylamide and DSM environment-friendly crosslinking agent CX-100.

5. The preparation method of flame retardant nuclear-shell environment-friendly

waterbome acrylate resin coating according to claim 2, characterized in that the preparation

method of the polypeptide comprises the following steps: mixing 50g of chrome leather

shavings, 500g of water, 10-12g of calcium oxide and 0.6-0.8g of sodium dodecyl benzene

sulfonate, which are stirred for 12h as pretreatment. Adding 5-1Og of calcium oxide, raising

the temperature to 70-80°C, and stirring the mixture for 5-8h to obtain hydrolyzate.

Performing suction filtration for the first time, adding oxalic acid into the filtered

hydrolysate to adjust the pH value of the hydrolysate to be 6.5-7.5, performing suction

filtration again, standing still. After the suction filtrate is stable, filtering the precipitate,

and the suction filtrate is dried until the water content is less than 5%, then the polypeptide

can be obtained.

6. The preparation method of flame retardant nuclear-shell environment-friendly

waterbome acrylate resin coating according to claim 2, characterized in that the emulsifier

is made by mixing sodium dodecyl benzene sulfonate and OP-10 according to the mass

ratio of 2: 1.