CN107686560B - Preparation method of cellulose flame-retardant modified composite phenolic foam - Google Patents

Abstract

A method for preparing a cellulose flame-retardant modified composite phenolic foam, comprising the use of flame retardant 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and itaconic acid to carry out a graft reaction, Preparation of DOPO-g-ITA for modified cellulose, and then using DOPO-g-ITA flame-retardant grafted cellulose, and used to prepare DOPO-g-ITA flame-retardant grafted cellulose modified phenolic resin, and finally used Preparation of cellulose composite phenolic foam. The interface compatibility between the modified cellulose prepared by the method of the invention and the phenolic resin matrix is significantly improved, the amount of cellulose added in the composite foam is greatly increased, and the prepared cellulose modified phenolic resin has moderate viscosity and strong expandability. , the mechanical properties of the prepared cellulose composite phenolic foam are significantly improved, the pulverization rate is significantly reduced, and the flame retardancy is slightly improved, which reduces the production cost of the composite foam, which is beneficial to the popularization and application of the phenolic foam composite material.

Description

A kind of preparation method of cellulose flame retardant modified composite phenolic foam

technical field

The invention belongs to the field of preparation of composite materials, in particular to a preparation method of a cellulose flame-retardant modified composite phenolic foam.

Background technique

Phenolic foam is a kind of thermosetting foam that is foamed and cured at a certain temperature after blending various additives (including surfactants, foaming agents, curing agents, etc.) with phenolic resin. Compared with polyurethane and polystyrene foam, phenolic foam has the advantages of good fire resistance, heat resistance, self-extinguishing, flame penetration resistance, less smoke in fire, no dripping and so on. As a thermal insulation material, phenolic foam is widely used in large public buildings, special ships, aviation equipment, oil pipelines and other places with high fire rating requirements. However, phenolic foam itself has the defects of high brittleness and high pulverization rate, which seriously limit its popularization and application.

In recent years, fires caused by non-flame retardant insulation materials of high-rise buildings have occurred frequently, resulting in a large number of casualties and property losses. As a foam insulation material with self-flame retardant properties, phenolic foam and its composite materials have gradually become a research hotspot, especially the modification of phenolic foam with natural fibers or cellulose to prepare phenolic foam composite materials. A batch of inventions have been applied for: CN201611106054.1 reports a preparation method of nanocellulose modified phenolic foam, by introducing nanocellulose into expandable phenolic resin to prepare modified phenolic foam, using the small size of nanocellulose , high specific surface area, high mechanical strength and other characteristics improve the mechanical properties of foam, and achieve the effect of toughening phenolic foam; CN201410584376.1 reported a preparation method of cellulose-modified phenolic foam, which is prepared by partially replacing phenol with cellulose solution Cellulose phenolic resin is then foamed to prepare cellulose modified phenolic foam. The introduction of cellulose solution can partially replace phenol, reduce the production cost of phenolic foam, and promote the efficient utilization of biomass resources; CN104004319A reported a kind of Plant fiber reinforced thermal insulation and flame retardant phenolic foam material and preparation method thereof are prepared by mechanically mixing plant fibers with different lengths of hollow structure after being soaked in flame retardant with phenolic resin and various additives, and then foaming and curing. The plant fiber-reinforced phenolic foam material used for the interior and exterior walls of buildings has good thermal insulation and flame-retardant properties, and can reduce the production cost of the phenolic foam material; CN102114659A reports a fiber-reinforced flame-retardant foam composite board and a preparation method thereof. The fiber-reinforced phenolic foam or melamine-modified urea-formaldehyde foam treated with coupling agent is used as the core material, and the flat plate is attached to the outer layer of the foam core material to prepare a laminated composite foam composite material. The composite board has excellent sound absorption and heat insulation. performance, the fiber-reinforced foam matrix material has excellent mechanical properties; CN104371269A reports a high-strength phenolic foam and a preparation method thereof. The high-strength phenolic foam is prepared by introducing bamboo fibers modified by a silane coupling agent into the phenolic foam. Plastic, the phenolic foam has excellent flame retardancy, heat resistance and solvent resistance, and has good mechanical strength.

However, most of the natural fibers used in the above documents are treated with coupling agents, and basically no flame retardant treatment is carried out. Even if the flame retardant treatment is carried out, it is only physically soaked with a flame retardant, and the modification effect is limited. In addition, the amount of natural fibers added is small. The effect of improving the comprehensive performance of phenolic foam composite materials is limited; in addition, due to the high price of nanocellulose, the use of nanocellulose to modify phenolic foam will increase the production cost of composite foam.

As one of the most abundant renewable resources in nature, cellulose has the advantages of low price, degradability, regular structure, easy chemical modification and special mechanical properties. It has been widely used in composite materials, textiles, drug delivery, and health care products. and membrane materials. By chemically modifying cellulose, various functional polymers or functional groups can be grafted onto the main chain of cellulose, thereby broadening the application field of cellulose and improving the added value of cellulose.

SUMMARY OF THE INVENTION

Technical problem to be solved: The present invention provides a preparation method of cellulose flame retardant modified composite phenolic foam, aiming at improving the interfacial compatibility between cellulose and phenolic resin matrix, greatly increasing the amount of cellulose added in the composite foam, Solve the problem that cellulose is difficult to mix evenly in the later foaming process, improve the mechanical properties of phenolic foam composites, reduce the pulverization rate of phenolic foam composites, and improve the composite material without reducing the flame retardancy of phenolic foam composites. Comprehensive properties of phenolic foam.

Technical scheme: a preparation method of cellulose flame retardant modified composite phenolic foam, comprising the following two steps: 1) preparation of DOPO-g-ITA: using xylene as a solvent, under nitrogen protection, according to 9,10- Dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) reacts with itaconic acid (ITA) at a temperature of 120～130℃ for 4～5h to obtain DOPO-g-ITA, DOPO and ITA The molar ratio is 1 to 1.3; 2) Preparation of DOPO-g-ITA modified cellulose: using xylene as solvent and K ₂ CO ₃ as catalyst, add cellulose into the reactor, and wait until the cellulose is completely dissolved in ethylene glycol. Add DOPO-g-ITA after toluene, the molar ratio of cellulose and DOPO-g-ITA is 1~4, the addition amount of K ₂ CO ₃ is 15~20% of the mass of cellulose, and the reaction temperature is 120~130℃ 8～9h, then suction filtration, washing and drying at 60～65℃ to obtain DOPO-g-ITA modified cellulose; 3) Preparation of flame retardant grafted cellulose modified phenolic resin: add 1mol phenol to the reaction vessel and DOPO-g-ITA modified cellulose which accounts for 2-30% of the mass of phenol, the temperature is raised to 90-95 ℃ for 30-40 min, and then 0.45-0.55 mol of paraformaldehyde, 1.28 mol of water and 0.0025 mol of CaO are added, Keep the reaction at 90～95℃ for 30～40min, after the reaction, the temperature is lowered to 85～90℃, add 0.675～0.825mol paraformaldehyde and 0.06～0.08mol 50wt.% NaOH solution, and react at 85～90℃ for 50～70min, Then cool down to 80～85℃, add 0.675～0.825mol paraformaldehyde and 0.06～0.08mol 50wt.% NaOH solution, react at 80～85℃ for 50～70min, then cool down to 75～80℃, add 0.03～0.04mol 50wt.% NaOH solution, react at 75～80℃ for 30～40min, cool down and cool to below 40℃ and discharge to obtain flame retardant grafted cellulose modified phenolic resin, in this process, the molar ratio of formaldehyde and phenol is controlled to be 1.8～ 2.2, the molar ratio of 50wt.% NaOH and phenol is 0.15-0.2; 4) Preparation of flame retardant grafted cellulose composite phenolic foam: adding curing agent, surfactant, and foaming agent to flame retardant grafted cellulose to modify In the phenolic resin, in parts by weight: flame retardant grafted cellulose modified phenolic resin is 100 parts, surfactant is 5-8 parts, curing agent is 20-30 parts, foaming agent is 5-8 parts ; Stir evenly, place it in a mold to foam and solidify at 60-70°C, and obtain flame-retardant modified fiber composite phenolic foam.

Preferably, in the preparation of the above DOPO-g-ITA, the molar ratio of DOPO to ITA is 1.3.

Preferably, the cellulose used in the flame retardant modification of the above-mentioned cellulose is ethyl cellulose or cellulose acetate.

Preferably, in the preparation of the above DOPO-g-ITA modified cellulose, the molar ratio of cellulose and DOPO-g-ITA is 2-3.

Preferably, in the preparation of the above DOPO-g-ITA modified cellulose, the addition amount of the catalyst K ₂ CO ₃ is 20% of the mass of the cellulose.

Preferably, in the preparation of the flame-retardant grafted cellulose-modified phenolic resin, the molar ratio of formaldehyde and phenol is 2.0.

Preferably, in the preparation of the flame-retardant grafted cellulose-modified phenolic resin, the molar ratio of the three batches of paraformaldehyde is 2:3:3.

Preferably, in the preparation of the flame-retardant grafted cellulose modified phenolic resin, the molar ratio of 50wt.% NaOH to phenol is 0.15-0.17, and the molar ratio of the three batches is 1:1:0.5.

Preferably, in the preparation of the above flame retardant grafted cellulose modified phenolic resin, the amount of DOPO-g-ITA modified cellulose added accounts for 20-25% of the mass of phenol.

Beneficial effect: the present invention adopts flame retardant DOPO and ITA to carry out graft reaction to prepare DOPO-g-ITA for modified cellulose, and then uses DOPO-g-ITA to flame retardant graft cellulose, and is used to prepare DOPO-g-ITA. g-ITA flame retardant grafted cellulose modified phenolic resin, and finally used in the preparation of cellulose composite phenolic foam. The interfacial compatibility between the modified cellulose prepared by the method of the invention and the phenolic resin matrix is significantly improved, the cellulose modified phenolic resin has moderate viscosity and strong expandability, and the mechanical properties of the cellulose composite phenolic foam are significantly improved. The conversion rate is significantly reduced, and the flame retardancy is slightly improved; the amount of cellulose added in the composite foam is greatly increased, which solves the problem that the addition of cellulose is difficult to mix evenly in the later foaming process, and the addition of a large amount of cellulose can reduce the composite foam. The production cost is beneficial to the popularization and application of the phenolic foam composite material.

Detailed ways

The cellulose in the embodiment of the present invention is DOPO-g-ITA flame-retardant modified ethyl cellulose or cellulose acetate respectively; The content is about 75wt.%; the surfactant in the embodiment is polysorbate-80; the curing agent in the embodiment is a mixed acid compounded by hydrochloric acid, phosphoric acid, p-toluenesulfonic acid and water, hydrochloric acid, phosphoric acid, p-toluenesulfonic acid The mass ratio to water is =8:4:6:3; in the examples, the foaming agent is petroleum ether, and the boiling point is 30-60° C.; the “parts” described in the examples represent parts by mass. The present invention will be further described below in conjunction with the examples.

Example 1

(1) Preparation of DOPO-g-ITA: using xylene as solvent, under nitrogen protection, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10- Oxide (DOPO) and itaconic acid (ITA) were added to the reactor, refluxed for 4 hours at a temperature of 120 °C, cooled to 110 °C, washed with acetone for several times after suction filtration, and dried to obtain DOPO-g-ITA solid White powder. (2) Preparation of DOPO-g-ITA flame retardant grafted ethyl cellulose: Dissolve the dried ethyl cellulose (water content <5%) in xylene solution (solid-liquid mass ratio is 1:20), Until completely dissolved, then add DOPO-g-ITA and 15% K ₂ CO ₃ accounting for the mass of cellulose according to the molar ratio of ethyl cellulose and DOPO-g-ITA as 1:1, react at 120 ° C for 8 hours, then suction filtration, Washing and drying at 60°C to obtain DOPO-g-ITA flame retardant grafted ethyl cellulose.

(3) Preparation of flame retardant grafted ethyl cellulose modified phenolic resin: According to the molar ratio of formaldehyde and phenol being 1.8:1, and the molar ratio of 50wt.% NaOH and phenol being 0.15:1, add 1 mol of phenol in the reaction vessel. Phenol and DOPO-g-ITA modified ethyl cellulose with a mass of 2% of phenol were heated to 90-95 °C for 30-40 min, and then 0.45 mol of paraformaldehyde, 1.28 mol of water and 0.0025 mol of CaO were added to maintain the temperature. Continue the reaction at 90～95℃ for 30～40min, after the reaction is completed, the temperature is lowered to 85～90℃, add 0.675mol paraformaldehyde and 0.06mol 50wt.% NaOH solution, react at 85～90℃ for 50～70min, and then cool down to 80～ 85°C, add 0.675mol paraformaldehyde and 0.06mol 50wt.% NaOH solution, react at 80～85°C for 50～70min, then cool down to 75～80°C, add 0.03mol 50wt.% NaOH solution, heat at 75～80°C The reaction is carried out for 30 to 40 minutes, and the temperature is cooled to below 40 °C to obtain the flame retardant grafted cellulose modified phenolic resin;

(4) Preparation of flame retardant modified ethyl cellulose composite phenolic foam: add curing agent, surfactant, and foaming agent to the above flame retardant grafted ethyl cellulose modified phenolic resin in proportion, and stir evenly , placed in a mold and foamed and cured at 70° C. to obtain flame-retardant modified ethyl cellulose composite phenolic foam. The raw material formula is calculated in parts by weight, and the composition is as follows: 100 parts of flame retardant grafted ethyl cellulose modified phenolic resin; 5 parts of surfactant; 20 parts of curing agent; 5 parts of foaming agent; see attachment for material properties Table 1.

Example 2

(1) Preparation of DOPO-g-ITA: using xylene as solvent, under nitrogen protection, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10- Oxide (DOPO) and itaconic acid (ITA) were added to the reactor, refluxed for 4.5 hours at a temperature of 125 °C, cooled to 110 °C, washed with acetone several times after suction filtration, and dried to obtain DOPO-g-ITA Solid white powder.

(2) Preparation of DOPO-g-ITA flame retardant grafted ethyl cellulose: Dissolve the dried ethyl cellulose (water content <5%) in xylene solution (solid-liquid mass ratio is 1:20), Until completely dissolved, then DOPO-g-ITA and 17% K ₂ CO ₃ were added at a molar ratio of 2:1 of ethyl cellulose and DOPO-g-ITA at 125°C for 8.5h, then suction filtered and washed at 65°C After drying, DOPO-g-ITA flame retardant grafted ethyl cellulose is obtained.

(3) Preparation of flame retardant grafted ethyl cellulose modified phenolic resin: according to the molar ratio of formaldehyde and phenol as 2.0:1, and the molar ratio of 50wt.% NaOH and phenol as 0.16:1, add 1 mol to the reactor phenol and DOPO-g-ITA modified ethyl cellulose accounting for 10% of the phenol mass, the temperature was raised to 93°C for 35min, then 0.5mol paraformaldehyde, 1.42mol water and 0.0025mol CaO were added, and the reaction was continued at 93°C for 35min , after the reaction was completed, the temperature was lowered to 87°C, 0.75mol paraformaldehyde and 0.064mol 50wt.% NaOH solution were added in proportion, reacted at 87°C for 60min, then cooled to 83°C, and 0.75mol paraformaldehyde and 0.064mol 50wt.% NaOH were added. %NaOH solution, react at 83°C for 60min, then cool down to 78°C, add 0.032mol 50wt.% NaOH solution, react at 78°C for 35min, cool down to below 40°C and discharge to obtain flame retardant grafted cellulose modified phenolic resin ;

(4) Preparation of flame retardant modified ethyl cellulose composite phenolic foam: add curing agent, surfactant, and foaming agent to the above flame retardant grafted ethyl cellulose modified phenolic resin in proportion, and stir evenly , placed in a mold and foamed and cured at 70° C. to obtain flame-retardant modified ethyl cellulose composite phenolic foam. The raw material formula is calculated in parts by weight and consists of: 100 parts of flame retardant grafted ethyl cellulose modified phenolic resin; 6 parts of surfactant; 24 parts of curing agent; 6 parts of foaming agent; Table 1.

Example 3

(1) Preparation of DOPO-g-ITA: using xylene as solvent, under nitrogen protection, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10- Oxide (DOPO) and itaconic acid (ITA) were added to the reactor, refluxed for 5 hours at a temperature of 130 °C, cooled to 110 °C, washed with acetone for several times after suction filtration, and dried to obtain DOPO-g-ITA solid White powder.

(2) Preparation of DOPO-g-ITA flame retardant grafted ethyl cellulose: Dissolve the dried ethyl cellulose (water content <5%) in xylene solution (solid-liquid mass ratio is 1:20), Until completely dissolved, then add DOPO-g-ITA and 20% K ₂ CO ₃ according to the molar ratio of ethyl cellulose and DOPO-g-ITA to 3:1, react at 130 °C for 9 h, then filter, wash and dry at 70 °C After drying, DOPO-g-ITA flame retardant grafted ethyl cellulose is obtained.

(3) Preparation of flame retardant grafted ethyl cellulose modified phenolic resin: according to the molar ratio of formaldehyde and phenol being 2.2:1, the molar ratio of 50wt.% NaOH and phenol being 0.17:1, adding 1mol phenol and accounting for phenol DOPO-g-ITA modified ethyl cellulose with 20% mass was heated to 95℃ for 40min, then 0.55mol paraformaldehyde, 1.56mol water and 0.0025mol CaO were added, and the reaction was continued at 95℃ for 40min. After the reaction, the temperature was lowered. to 90°C, add 0.825mol paraformaldehyde and 0.068mol 50wt.% NaOH solution, react at 90°C for 70min, then cool down to 85°C, add 0.825mol paraformaldehyde and 0.068mol 50wt.%NaOH solution, react at 85°C 70min, then cooled to 80°C, added 0.034mol 50wt.% NaOH solution, reacted at 80°C for 40min, cooled to below 40°C and discharged to obtain flame retardant grafted cellulose modified phenolic resin;

(4) Preparation of flame retardant modified ethyl cellulose composite phenolic foam: add curing agent, surfactant, and foaming agent to the above flame retardant grafted ethyl cellulose modified phenolic resin in proportion, and stir evenly , placed in a mold and foamed and cured at 70° C. to obtain flame-retardant modified ethyl cellulose composite phenolic foam. The raw material formula is calculated in parts by weight and consists of: 100 parts of flame retardant grafted ethyl cellulose modified phenolic resin; 7 parts of surfactant; 26 parts of curing agent; 7 parts of foaming agent; Table 1.

Example 4

(1) Preparation of DOPO-g-ITA: using xylene as solvent, under nitrogen protection, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10- Oxide (DOPO) and itaconic acid (ITA) were added to the reactor, refluxed for 5 hours at a temperature of 130 °C, cooled to 110 °C, washed with acetone for several times after suction filtration, and dried to obtain DOPO-g-ITA solid White powder.

(2) Preparation of DOPO-g-ITA flame retardant grafted ethyl cellulose: Dissolve the dried ethyl cellulose (water content <5%) in xylene solution (solid-liquid mass ratio is 1:20), Until completely dissolved, then add DOPO-g-ITA and 20% K ₂ CO ₃ according to the molar ratio of ethyl cellulose and DOPO-g-ITA to 4:1, react at 130°C for 9h, then filter, wash and bake at 60°C After drying, DOPO-g-ITA flame retardant grafted ethyl cellulose is obtained.

(3) Preparation of flame retardant grafted ethyl cellulose modified phenolic resin: according to the molar ratio of formaldehyde and phenol being 2.2:1, the molar ratio of 50wt.% NaOH and phenol being 0.2:1, adding 1mol of phenol and accounting for phenol The DOPO-g-ITA modified ethyl cellulose with 30% mass was heated to 95℃ for 40min, then 0.55mol paraformaldehyde, 1.56mol water and 0.0025mol CaO were added, and the reaction was continued at 95℃ for 40min. 90℃, add 0.825mol paraformaldehyde and 0.08mol 50wt.% NaOH solution, react at 90℃ for 70min, then cool down to 85℃, add 0.825mol paraformaldehyde and 0.08mol50wt.%NaOH solution, react at 85℃ for 70min, then Cooling to 80°C, adding 0.04mol 50wt.% NaOH solution, reacting at 80°C for 40min, cooling down to below 40°C and discharging to obtain flame retardant grafted cellulose modified phenolic resin;

(4) Preparation of flame retardant modified ethyl cellulose composite phenolic foam: add curing agent, surfactant, and foaming agent to the above flame retardant grafted ethyl cellulose modified phenolic resin in proportion, and stir evenly , placed in a mold and foamed and cured at 70° C. to obtain flame-retardant modified ethyl cellulose composite phenolic foam. The raw material formula is calculated in parts by weight and consists of: 100 parts of flame retardant grafted ethyl cellulose modified phenolic resin; 8 parts of surfactant; 30 parts of curing agent; 8 parts of foaming agent; Table 1.

Example 5

(1) Preparation of DOPO-g-ITA: using xylene as solvent, under nitrogen protection, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10- Oxide (DOPO) and itaconic acid (ITA) were added to the reactor, refluxed for 5 hours at a temperature of 130 °C, cooled to 110 °C, washed with acetone for several times after suction filtration, and dried to obtain DOPO-g-ITA solid White powder.

(2) Preparation of DOPO-g-ITA flame retardant grafted ethyl cellulose: Dissolve the dried ethyl cellulose (water content <5%) in xylene solution (solid-liquid mass ratio is 1:20), Until it is completely dissolved, then add DOPO-g-ITA and 20% K ₂ CO ₃ according to the molar ratio of ethyl cellulose and DOPO-g-ITA to 2:1 and react at 130 °C for 9 h, then filter, wash and dry at 60 °C After drying, DOPO-g-ITA flame retardant grafted ethyl cellulose is obtained.

(3) Preparation of flame retardant grafted ethyl cellulose modified phenolic resin: according to the molar ratio of formaldehyde and phenol as 2.0:1, and the molar ratio of 50wt.% NaOH and phenol as 0.15:1, add 1 mol to the reactor phenol and DOPO-g-ITA modified ethyl cellulose accounting for 20% of the phenol mass, the temperature was raised to 93 °C for 35 min, and then 0.5 mol of paraformaldehyde, 1.42 mol of water and 0.0025 mol of CaO were added, and the reaction was continued at 93 °C for 35 min. , after the reaction was completed, the temperature was lowered to 87°C, 0.6mol paraformaldehyde and 0.064mol 50wt.% NaOH solution were added in proportion, reacted at 87°C for 60min, then cooled to 83°C, and 0.75mol paraformaldehyde and 0.06mol 50wt.% were added. %NaOH solution, reacted at 83°C for 60min, then cooled to 78°C, added 0.03mol50wt.% NaOH solution, reacted at 78°C for 35min, cooled to below 40°C and discharged to obtain flame retardant grafted cellulose modified phenolic resin ;

(4) Preparation of flame retardant modified ethyl cellulose composite phenolic foam: add curing agent, surfactant, and foaming agent to the above flame retardant grafted ethyl cellulose modified phenolic resin in proportion, and stir evenly , placed in a mold and foamed and cured at 70° C. to obtain flame-retardant modified ethyl cellulose composite phenolic foam. The raw material formula is calculated in parts by weight, and the composition is as follows: 100 parts of flame retardant grafted ethyl cellulose modified phenolic resin; 5 parts of surfactant; 20 parts of curing agent; 5 parts of foaming agent; see attachment for material properties Table 1.

Example 6

(1) Preparation of DOPO-g-ITA: using xylene as solvent, under nitrogen protection, in a molar ratio of 1:1.3, an appropriate amount of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10 - Oxide (DOPO) and itaconic acid (ITA) were added to the reactor, refluxed for 5 hours at a temperature of 130 °C, cooled to 110 °C, washed with acetone for several times after suction filtration, and dried to obtain DOPO-g-ITA Solid white powder.

(2) Preparation of DOPO-g-ITA flame retardant grafted ethyl cellulose: Dissolve the dried ethyl cellulose (water content <5%) in xylene solution (solid-liquid mass ratio is 1:20), Until completely dissolved, then add DOPO-g-ITA and 20% K ₂ CO ₃ according to the molar ratio of ethyl cellulose and DOPO-g-ITA to 3:1, react at 130 ° C for 9 h, then filter, wash and dry at 60 ° C After drying, DOPO-g-ITA flame retardant grafted ethyl cellulose is obtained.

(3) Preparation of flame retardant grafted ethyl cellulose modified phenolic resin: according to the molar ratio of formaldehyde and phenol as 2.0:1, and the molar ratio of 50wt.% NaOH and phenol as 0.17:1, add 1 mol to the reactor phenol and DOPO-g-ITA modified ethyl cellulose accounting for 25% of the phenol mass, the temperature was raised to 93 °C for 35 min, and then 0.5 mol of paraformaldehyde, 1.42 mol of water and 0.0025 mol of CaO were added, and the reaction was continued at 93 °C for 35 min. , after the reaction was completed, the temperature was lowered to 87 ° C, 0.6 mol of paraformaldehyde and 0.068 mol of 50wt.% NaOH solution were added in proportion, and the reaction was carried out at 87 ° C for 60 min, then cooled to 83 ° C, and 0.75 mol of paraformaldehyde and 0.068 mol of 50wt.% NaOH were added. %NaOH solution, react at 83°C for 60min, then cool down to 78°C, add 0.034mol 50wt.% NaOH solution, react at 78°C for 35min, cool down to below 40°C and discharge to obtain flame retardant grafted cellulose modified phenolic resin ;

(4) Preparation of flame retardant modified ethyl cellulose composite phenolic foam: add curing agent, surfactant, and foaming agent to the above flame retardant grafted ethyl cellulose modified phenolic resin in proportion, and stir evenly , placed in a mold and foamed and cured at 70° C. to obtain flame-retardant modified ethyl cellulose composite phenolic foam. The raw material formula is calculated in parts by weight and consists of: 100 parts of flame retardant grafted ethyl cellulose modified phenolic resin; 8 parts of surfactant; 30 parts of curing agent; 8 parts of foaming agent; Table 1.

Example 7

(1) Preparation of DOPO-g-ITA: using xylene as solvent, under nitrogen protection, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10- Oxide (DOPO) and itaconic acid (ITA) were added to the reactor, refluxed for 4 hours at a temperature of 120 °C, cooled to 110 °C, washed with acetone for several times after suction filtration, and dried to obtain DOPO-g-ITA solid White powder.

(2) Preparation of DOPO-g-ITA flame retardant grafted cellulose acetate: Dissolve dried cellulose acetate (water content <5%) in xylene solution (solid-liquid mass ratio of 1:20) until complete Dissolve, then add DOPO-g-ITA and 15% K ₂ CO ₃ according to the 1:1 molar ratio of cellulose acetate and DOPO-g-ITA, react at 120°C for 8h, then filter, wash and dry at 60°C to obtain DOPO-g-ITA flame retardant grafted cellulose acetate.

(3) Preparation of flame retardant grafted cellulose acetate modified phenolic resin: according to the molar ratio of formaldehyde and phenol as 1.8:1, and the molar ratio of 50wt.% NaOH and phenol as 0.15:1, add 1mol of phenol in the reaction vessel and DOPO-g-ITA modified cellulose acetate which accounts for 2% of the mass of phenol, heat up to 90～95℃ and react for 30～40min, then add 0.45mol paraformaldehyde, 1.28mol water and 0.0025mol CaO, keep 90～90～ Continue the reaction at 95°C for 30-40min, after the reaction is completed, the temperature is lowered to 85-90°C, add 0.675mol paraformaldehyde and 0.06mol 50wt.% NaOH solution, react at 85-90°C for 50-70min, and then cool down to 80-85°C , add 0.675mol paraformaldehyde and 0.06mol 50wt.%NaOH solution, react at 80～85℃ for 50～70min, then cool down to 75～80℃, add 0.03mol 50wt.%NaOH solution, react at 75～80℃ for 30 minutes ~40min, cooling down to below 40℃ and discharging to obtain flame retardant grafted cellulose modified phenolic resin;

(4) Preparation of flame retardant modified cellulose acetate composite phenolic foam: add curing agent, surfactant, and foaming agent to the above flame retardant grafted cellulose acetate modified phenolic resin in proportion, stir evenly, and set aside Foam and solidify in a mold at 70° C. to obtain flame-retardant modified cellulose acetate composite phenolic foam. The raw material formula is calculated in parts by weight and consists of: 100 parts of flame retardant grafted cellulose acetate modified phenolic resin; 5 parts of surfactant; 20 parts of curing agent; 5 parts of foaming agent; see attached table for material properties 1.

Example 8

(1) Preparation of DOPO-g-ITA: using xylene as solvent, under nitrogen protection, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10- Oxide (DOPO) and itaconic acid (ITA) were added to the reactor, refluxed for 4.5 hours at a temperature of 125 °C, cooled to 110 °C, washed with acetone several times after suction filtration, and dried to obtain DOPO-g-ITA Solid white powder.

(2) Preparation of DOPO-g-ITA flame retardant grafted cellulose acetate: Dissolve dried cellulose acetate (water content <5%) in xylene solution (solid-liquid mass ratio of 1:20) until complete Dissolve, then add DOPO-g-ITA and 17% K ₂ CO ₃ according to the 2:1 molar ratio of cellulose acetate and DOPO-g-ITA, react at 125°C for 8.5h, then filter, wash and dry at 65°C. Obtain DOPO-g-ITA flame retardant grafted cellulose acetate.

(3) Preparation of flame retardant grafted cellulose acetate modified phenolic resin: according to the molar ratio of formaldehyde and phenol being 2.0:1, the molar ratio of 50wt.% NaOH and phenol being 0.16:1, adding 1mol of Phenol and DOPO-g-ITA modified cellulose acetate, which accounts for 10% of the mass of phenol, were heated to 93 °C for 35 min, then 0.5 mol of paraformaldehyde, 1.42 mol of water and 0.0025 mol of CaO were added, and the reaction was continued at 93 °C for 35 min. After the end, the temperature was lowered to 87°C, 0.75mol paraformaldehyde and 0.064mol 50wt.% NaOH solution were added in proportion, reacted at 87°C for 60 min, then cooled to 83°C, and 0.75mol paraformaldehyde and 0.064mol 50wt.% NaOH were added. The solution was reacted at 83°C for 60min, then cooled to 78°C, added with 0.032mol 50wt.% NaOH solution, reacted at 78°C for 35min, cooled to below 40°C and discharged to obtain flame retardant grafted cellulose modified phenolic resin;

(4) Preparation of flame retardant modified cellulose acetate composite phenolic foam: add curing agent, surfactant, and foaming agent to the above flame retardant grafted cellulose acetate modified phenolic resin in proportion, stir evenly, and set aside Foam and solidify in a mold at 70° C. to obtain flame-retardant modified cellulose acetate composite phenolic foam. The raw material formula is calculated in parts by weight and consists of: 100 parts of flame retardant grafted cellulose acetate modified phenolic resin; 6 parts of surfactant; 23 parts of curing agent; 7 parts of foaming agent; see attached table for material properties 1.

Example 9

(1) Preparation of DOPO-g-ITA: using xylene as solvent, under nitrogen protection, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10- Oxide (DOPO) and itaconic acid (ITA) were added to the reactor, refluxed for 5 hours at a temperature of 130 °C, cooled to 110 °C, washed with acetone for several times after suction filtration, and dried to obtain DOPO-g-ITA solid White powder.

(2) Preparation of DOPO-g-ITA flame retardant grafted cellulose acetate: Dissolve dried ethyl cellulose (water content <5%) in xylene solution (solid-liquid mass ratio of 1:20) until Completely dissolve, then add DOPO-g-ITA and 20% K ₂ CO ₃ according to the molar ratio of cellulose acetate and DOPO-g-ITA as 3:1, react at 130°C for 9h, then filter, wash and dry at 70°C. Obtain DOPO-g-ITA flame retardant grafted cellulose acetate.

(3) Preparation of flame-retardant grafted cellulose acetate-modified phenolic resin: according to the molar ratio of formaldehyde and phenol as 2.2:1, and the molar ratio of 50wt.% NaOH and phenol as 0.18:1, add 1mol phenol and account for the mass of phenol 20% DOPO-g-ITA modified cellulose acetate, heated to 95℃ for 40min, then added 0.55mol paraformaldehyde, 1.56mol water and 0.0025mol CaO, kept at 95℃ for 40min, cooled to 90 after the reaction ℃, add 0.825mol paraformaldehyde and 0.072mol 50wt.%NaOH solution, react at 90℃ for 70min, then cool down to 85℃, add 0.825mol paraformaldehyde and 0.072mol 50wt.%NaOH solution, react at 85℃ for 70min, Then the temperature is lowered to 80°C, 0.036mol 50wt.% NaOH solution is added, the reaction is carried out at 80°C for 40min, the temperature is cooled to below 40°C, and the material is discharged to obtain the flame retardant grafted cellulose modified phenolic resin;

(4) Preparation of flame retardant modified cellulose acetate composite phenolic foam: add curing agent, surfactant, and foaming agent to the above flame retardant grafted cellulose acetate modified phenolic resin in proportion, stir evenly, and set aside Foam and solidify in a mold at 70° C. to obtain flame-retardant modified cellulose acetate composite phenolic foam. The raw material formula is calculated in parts by weight and consists of: 100 parts of flame retardant grafted cellulose acetate modified phenolic resin; 7 parts of surfactant; 26 parts of curing agent; 7 parts of foaming agent; see attached table for material properties 1.

Example 10

(1) Preparation of DOPO-g-ITA: using xylene as solvent, under nitrogen protection, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10- Oxide (DOPO) and itaconic acid (ITA) were added to the reactor, refluxed for 5 hours at a temperature of 130 °C, cooled to 110 °C, washed with acetone for several times after suction filtration, and dried to obtain DOPO-g-ITA solid White powder.

(2) Preparation of DOPO-g-ITA flame retardant grafted cellulose acetate: Dissolve dried cellulose acetate (water content <5%) in xylene solution (solid-liquid mass ratio of 1:20) until complete Dissolve, then add DOPO-g-ITA and 20% K ₂ CO ₃ according to the molar ratio of cellulose acetate and DOPO-g-ITA to 4:1, react at 130°C for 9h, then filter, wash and dry at 60°C to obtain DOPO-g-ITA flame retardant grafted cellulose acetate.

(3) Preparation of flame-retardant grafted cellulose acetate-modified phenolic resin: according to the molar ratio of formaldehyde and phenol as 2.2:1, and the molar ratio of 50wt.% NaOH and phenol as 0.2:1, add 1mol of phenol and the mass of phenol. 30% DOPO-g-ITA modified cellulose acetate, heated to 95℃ for 40min, then added 0.55mol paraformaldehyde, 1.56mol water and 0.0025mol CaO, kept at 95℃ for 40min, cooled to 90℃ after the reaction , add 0.825mol paraformaldehyde and 0.08mol50wt.%NaOH solution, react at 90℃ for 70min, then cool down to 85℃, add 0.825mol paraformaldehyde and 0.08mol50wt.%NaOH solution, react at 85℃ for 70min, and then cool down to 80°C, add 0.04mol 50wt.% NaOH solution, react at 80°C for 40min, cool down and cool to below 40°C and discharge to obtain flame retardant grafted cellulose modified phenolic resin;

(4) Preparation of flame retardant modified cellulose acetate composite phenolic foam: add curing agent, surfactant, and foaming agent to the above flame retardant grafted cellulose acetate modified phenolic resin in proportion, stir evenly, and set aside Foam and solidify in a mold at 70° C. to obtain flame-retardant modified cellulose acetate composite phenolic foam. The raw material formula is calculated in parts by weight and consists of: 100 parts of flame retardant grafted cellulose acetate modified phenolic resin; 8 parts of surfactant; 30 parts of curing agent; 8 parts of foaming agent; see attached table for material properties 1.

Example 11

(1) Preparation of DOPO-g-ITA: using xylene as solvent, under nitrogen protection, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10- Oxide (DOPO) and itaconic acid (ITA) were added to the reactor, refluxed for 5 hours at a temperature of 130 °C, cooled to 110 °C, washed with acetone for several times after suction filtration, and dried to obtain DOPO-g-ITA solid White powder.

(2) Preparation of DOPO-g-ITA flame retardant grafted cellulose acetate: Dissolve dried cellulose acetate (water content <5%) in xylene solution (solid-liquid mass ratio of 1:20) until complete Dissolve, then add DOPO-g-ITA and 20% K ₂ CO ₃ according to the molar ratio of cellulose acetate and DOPO-g-ITA as 2:1, react at 130°C for 9h, then filter, wash and dry at 60°C to obtain DOPO-g-ITA flame retardant grafted cellulose acetate.

(3) Preparation of flame-retardant grafted cellulose acetate-modified phenolic resin: according to the molar ratio of formaldehyde and phenol being 2.0:1, and the molar ratio of 50wt.% NaOH and phenol being 0.15:1, 1 mol of phenol was added to the reactor. Phenol and DOPO-g-ITA modified cellulose acetate, which accounts for 20% of the mass of phenol, were heated to 93 °C for 35 min, and then 0.5 mol of paraformaldehyde, 1.42 mol of water and 0.0025 mol of CaO were added, and the reaction was continued at 93 °C for 35 min. After the end, the temperature was lowered to 87°C, 0.75mol paraformaldehyde and 0.06mol 50wt.% NaOH solution were added in proportion, reacted at 87°C for 60 min, then cooled to 83°C, 0.75mol paraformaldehyde and 0.06mol 50wt.% NaOH were added The solution was reacted at 83°C for 60min, then cooled to 78°C, added with 0.03mol 50wt.% NaOH solution, reacted at 78°C for 35min, cooled to below 40°C and discharged to obtain flame retardant grafted cellulose modified phenolic resin;

(4) Preparation of flame retardant modified cellulose acetate composite phenolic foam: add curing agent, surfactant, and foaming agent to the above flame retardant grafted cellulose acetate modified phenolic resin in proportion, stir evenly, and set aside Foam and solidify in a mold at 70° C. to obtain flame-retardant modified cellulose acetate composite phenolic foam. The raw material formula is calculated in parts by weight and consists of: 100 parts of flame retardant grafted cellulose acetate modified phenolic resin; 8 parts of surfactant; 30 parts of curing agent; 8 parts of foaming agent; see attached table for material properties 1.

Example 12

(1) Preparation of DOPO-g-ITA: using xylene as solvent, under nitrogen protection, in a molar ratio of 1:1.3, an appropriate amount of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10 - Oxide (DOPO) and itaconic acid (ITA) were added to the reactor, refluxed for 5 hours at a temperature of 130 °C, cooled to 110 °C, washed with acetone for several times after suction filtration, and dried to obtain DOPO-g-ITA Solid white powder.

(2) Preparation of DOPO-g-ITA flame retardant grafted cellulose acetate: Dissolve dried cellulose acetate (water content <5%) in xylene solution (solid-liquid mass ratio of 1:20) until complete Dissolve, then add DOPO-g-ITA and 20% K ₂ CO ₃ according to the molar ratio of cellulose acetate and DOPO-g-ITA as 3:1, react at 130 ° C for 9 h, then filter, wash and dry at 60 ° C to obtain DOPO-g-ITA flame retardant grafted cellulose acetate.

(3) Preparation of flame retardant grafted cellulose acetate modified phenolic resin: according to the molar ratio of formaldehyde and phenol being 2.0:1, the molar ratio of 50wt.% NaOH and phenol being 0.17:1, adding 1mol of Phenol and DOPO-g-ITA modified cellulose acetate that accounts for 25% of the mass of phenol were heated to 93°C for 35min, then 0.5mol paraformaldehyde, 1.42mol water and 0.0025mol CaO were added, and the reaction was continued at 93°C for 35min. After the end, the temperature was lowered to 87°C, 0.75mol paraformaldehyde and 0.068mol 50wt.% NaOH solution were added in proportion, reacted at 87°C for 60 minutes, then cooled to 83°C, and 0.75mol paraformaldehyde and 0.068mol 50wt.% NaOH were added. The solution was reacted at 83°C for 60min, then cooled to 78°C, added with 0.034mol 50wt.% NaOH solution, reacted at 78°C for 35min, cooled to below 40°C and discharged to obtain flame retardant grafted cellulose modified phenolic resin;

(4) Preparation of flame retardant modified cellulose acetate composite phenolic foam: add curing agent, surfactant, and foaming agent to the above flame retardant grafted cellulose acetate modified phenolic resin in proportion, stir evenly, and set aside Foam and solidify in a mold at 70° C. to obtain flame-retardant modified cellulose acetate composite phenolic foam. The raw material formula is calculated in parts by weight and consists of: 100 parts of flame retardant grafted cellulose acetate modified phenolic resin; 5 parts of surfactant; 20 parts of curing agent; 5 parts of foaming agent; see attached table for material properties 1.

Table 1 Properties of cellulose-modified phenolic resins and foams with different formulations

When the molar ratio of formaldehyde and phenol is 2.0:1, the addition amount of DOPO-g-ITA modified cellulose is 20%-25%, and the molar ratio of 50wt.% NaOH solution to phenol is 0.15-0.17, the prepared cellulose modified cellulose is prepared. The viscosity and solid content of the phenolic resin are moderate, and the expandability is strong; when the flame retardant grafted cellulose modified phenolic resin is 100 parts; the surfactant is 5 parts; the curing agent is 20 parts; the foaming agent is 5 parts. The modified cellulose composite phenolic foam has moderate apparent density, high oxygen index and flexural and compressive strength, low pulverization rate, and excellent comprehensive performance of composite foam.

Claims (1)

1. a preparation method of cellulose flame retardant modified composite phenolic foam is characterized in that comprising the following four steps: 1) preparation of DOPO-g-ITA: taking xylene as a solvent, under nitrogen protection, according to 9, 10-Dihydro-9-oxa-10-phosphaphenanthrene-10-oxide DOPO and itaconic acid ITA were reacted at 120~130℃ for 4~5h to obtain DOPO-g-ITA, the molar ratio of DOPO and ITA 1.3; 2) Preparation of DOPO-g-ITA modified cellulose: using xylene as solvent and K ₂ CO ₃ as catalyst, add cellulose into the reactor, and add DOPO after cellulose is completely dissolved in xylene -g-ITA, the molar ratio of cellulose and DOPO-g-ITA is 2~3, the addition amount of K ₂ CO ₃ is 20% of the mass of cellulose, react at 120~130℃ for 8~9 hours, and then pump Filter, wash and dry at 60~65°C to obtain DOPO-g-ITA modified cellulose; the cellulose is ethyl cellulose or cellulose acetate; 3) flame retardant grafted cellulose modified phenolic resin Preparation: add 1 mol of phenol and DOPO-g-ITA modified cellulose with a mass of 20-25% of the phenol in the reaction vessel, heat up to 90-95 ℃ and react for 30-40 min, and then add 0.45-0.55 mol of paraformaldehyde , 1.28 mol of water and 0.0025 mol of CaO, kept at 90-95 ℃ and continued to react for 30-40 min, cooled to 85-90 ℃ after the reaction, added 0.675-0.825 mol of paraformaldehyde and 0.06-0.08 mol of 50wt. React at 85-90°C for 50~70min, then cool down to 80~85°C, add 0.675~0.825mol paraformaldehyde and 0.06~0.08mol 50wt.%NaOH solution, react at 80~85°C for 50~70min, and then cool down to 75 ~80°C, add 0.03~0.04mol 50wt.% NaOH solution, react at 75~80°C for 30~40min, cool down to below 40°C and discharge to obtain flame retardant grafted cellulose modified phenolic resin. During this process, control the The molar ratio of formaldehyde and phenol is 2.0, the molar ratio of three batches of paraformaldehyde is 2:3:3, the molar ratio of 50wt.%NaOH and phenol is 0.15~0.17, and the molar ratio of three batches of 50wt.%NaOH solution 1:1:0.5; 4) Preparation of flame retardant grafted cellulose composite phenolic foam: adding curing agent, surfactant, and foaming agent to flame retardant grafted cellulose modified phenolic resin, wherein by weight Total: 100 parts of flame retardant grafted cellulose modified phenolic resin, 5 to 8 parts of surfactant, 20 to 30 parts of curing agent, and 5 to 8 parts of foaming agent; stir evenly, place in the mold Foaming and curing at 60-70 DEG C, the flame-retardant modified fiber composite phenolic foam is obtained.