CN102746764A - Method of preparing transparent and decorated fireproof coating with two components - Google Patents

Abstract

The invention relates to a method of preparing a transparent and decorated fireproof coating with two components. The method comprises steps of: preparing a polyethylene-glycol-grafted polyphosphate by using polyphosphoric acid, pentaerythritol and polyethylene glycol through a solution synthesis method; preparing an aqueous solution or an ethanol solution with a certain concentration of the grafted polyphosphate, and blending the solution with an aqueous amino resin by stirring to get the transparent and decorated fireproof coating with two components. According to the present invention, the preparation method is simple and feasible, the cost is low, and the prepared transparent and decorated fireproof coating with two components can greatly improve flexibility of a coating film on the basis of ensuring excellent fireproof property of the coating.

Description

Preparation method of two-component transparent finish type fireproof coating

technical field

The invention relates to a preparation method of a two-component transparent finish type fireproof paint.

Background technique

Coating decorative fire retardant paint is currently the best means of wood fire prevention. When wood is exposed to fire, it can achieve the purpose of prolonging the fire resistance of wood and slowing down the spread of fire, so that there is enough time for fighting and reducing the loss caused by fire as much as possible. Decorative fire retardant coatings are generally divided into two types: intumescent and non-expandable. Since the intumescent fireproof system can rapidly foam to form a porous carbonized layer tens or even hundreds of times the thickness of the original coating when it is exposed to fire, which effectively blocks the transfer of heat and isolates the substrate from the air. The fireproof performance is better than that of the non-expandable system. Therefore, it has been extensively researched and applied. Most of the research at home and abroad is based on intumescent systems, including copolymerization or chemically modified polymers, adding flame retardants, etc. Traditional systems generally contain P, Si, B, N and other elements. With the addition of these inorganic fire retardant additives, the transparency of the coating film of fire retardant coatings will be weakened, and even the original shape of the substrate will be destroyed. For wood structure fire retardant coatings, its decoration is precisely the key factor to be considered. Timber is generally used in construction, cultural relics protection, building decoration and high-grade furniture, and these building materials have very high requirements aspect keeping the original shape, so the decoration of wood fireproof coatings is also required very high. However, if we only consider its decorative properties and reduce the addition of fire retardant additives, the fire performance of the fire retardant coating will not meet the requirements, resulting in the failure to effectively control the fire hazard. Therefore, the research and development of transparent fireproof coatings (or fireproof varnishes) with both fireproof and decorative functions has received great attention both at home and abroad.

my country's research on transparent decorative fireproof coatings started relatively late, and some achievements have been made since the early 1980s. For a long period of time, the development of transparent fireproof coatings in China has focused on the use of amino resins such as urea-formaldehyde resins, melamine-formaldehyde resins, melamine-formaldehyde-urea copolymer resins or modified amino resins as film-forming substances. In addition to amino resins, Domestically, a lot of research has been done on the application of epoxy resin, acrylate resin, polyurethane, polyester and other systems in transparent fireproof coatings. Most of the preparation methods are to prepare various fireproof additives first, and then use various methods to It is compounded with the film-forming substances of the above systems to prepare a transparent decorative fireproof coating.

Although the appearance of foreign transparent intumescent fire retardant coatings is much earlier than that in China, the concept of transparent fire retardant coatings has not been specifically proposed, and there are few patents and documents on transparent fire retardant coatings. Compared with domestic independent research on transparent fire retardant coatings, foreign scholars are more focused on the development of various fire retardant additive systems, adding fire retardant additives with various characteristics to a suitable matrix resin, or physical blending or chemical reaction Various products (including various plastic products and coatings, etc.) including transparent fireproof coatings are produced.

At present, the transparent decorative fire retardant coatings at home and abroad are still in their infancy. There are relatively few such coatings on the market, and even rarer ones that can be put into practical application. One of the major factors limiting the practical application of transparent decorative fire retardant coatings is that the flexibility of the coating film is too poor, and the coating film cracks and other phenomena will appear shortly after the coating is applied to the substrate and cured. The present invention attempts to introduce flexible chain segments such as polyethylene glycol into phosphate ester to prepare fireproof coatings, so as to improve the flexibility of the coating film.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies of the prior art and provide a method for preparing a two-component transparent finish type fireproof coating with high film flexibility.

The preparation method of a kind of two-component transparent finishing type fireproof coating provided by the present invention, the specific steps are as follows:

(1) Preparation of grafted polyphosphate

Dissolve polyphosphoric acid in an appropriate amount of solvent, heat and stir until polyphosphoric acid is evenly dissolved. Add pentaerythritol to the system, heat up to 80-90° C. to react, and use a rotary evaporator to evaporate the solvent after reacting for 6-10 hours. The product is then grafted with polyethylene glycol under the reaction condition of 100-120° C. for 8-24 hours to obtain polyethylene glycol-grafted polyphosphate. Among them: polyphosphoric acid accounts for 40wt-50wt%, pentaerythritol accounts for 25wt-40wt%, polyethylene glycol accounts for 20wt-25wt%, and its total weight meets 100%, and the solvent used is 200wt%-300wt% of the total weight.

(2) Synthetic fire retardant coating

The grafted polyphosphate ester obtained in step (1) is made into a solution, and blended and stirred with a water-based amino resin to obtain a two-component transparent finish type fireproof coating; the grafted polyphosphate ester and water-based amino resin The mass ratio is 1:2-1:4.

Among the present invention, described polyphosphoric acid is tetrapolyphosphoric acid; Molecular weight is 338, and its structural formula is:

In the present invention, the water-based amino resin is one or more of water-based hexamethylolmelamine-formaldehyde resin, water-based low-etherification melamine-formaldehyde resin or water-based urea-formaldehyde resin.

In the present invention, the solvent is one of dioxane, tetrahydrofuran, dimethylformamide, dimethyl sulfoxide or acetone.

In the present invention, the polyethylene glycol is one of PEG200, PEG300, PEG400, PEG600, PEG800, PEG1000, PEG1500 or PEG2000.

In the present invention, the grafted polyphosphate solution is a 50wt%-66wt% ethanol solution of grafted polyphosphate or an aqueous solution of grafted polyphosphate.

The invention has the advantages of wide source of raw materials, all required raw materials are common chemicals, and low cost; the preparation method is simple and easy, the reaction conditions are loose, and each stage is easy to operate, so that the whole coating preparation process is very convenient; The obtained two-component transparent fireproof coating has excellent fireproof performance of the coating because it contains sufficient carbon source, nitrogen source, phosphorus source, etc. necessary for the fireproof system; and because it contains polyethylene glycol, the coating film The flexibility of the paint is very good, and the whole paint is colorless and transparent, which ensures that it has an excellent finishing effect.

Detailed ways

The following examples are to further illustrate the present invention, but not to limit the scope of the present invention.

Waterborne hexamethylolmelamine formaldehyde resin is synthesized in laboratory. Synthesis method: add formaldehyde aqueous solution (mass concentration 37%) in a three-necked bottle, adjust the pH to 8~9 with alkali, stir, then add melamine, heat until the solution is clear and transparent, and keep warm for a period of time to form hexamethylolmelamine solid , cooled, and filtered to remove water. Add excess methanol to the product, adjust the pH to 2~3 with concentrated acid, heat etherification, add alkali to adjust the pH to 8~9, and distill under reduced pressure; add methanol, adjust the pH to 2~3, and heat for the second time Etherification, adding alkali to make the pH 8~9, and finally distilling under reduced pressure until there is no distillate to obtain the water-based hexamethylolmelamine formaldehyde resin.

Water-based low-etherification melamine-formaldehyde resin: product of Shanghai Xinhua Resin Factory, model 5386-60.

Water-based urea-formaldehyde resin: product of Shanghai Xinhua Resin Factory, model 578-1.

Example 1

(1) Dissolve 50g of polyphosphoric acid in 200ml of dioxane, heat and stir until the polyphosphoric acid is evenly dissolved. 25 g of pentaerythritol was added to the system, and the temperature was raised to 80° C. for reaction. After 6 hours of reaction, the solvent was evaporated using a rotary evaporator. The product was then grafted with 25g PEG200 under the reaction conditions of 100°C for 8 hours to obtain polyethylene glycol grafted polyphosphate;

(2) Make a 50% aqueous solution of the prepared grafted polyphosphate, weigh 400g, and blend and stir for 30 minutes. After the stirring is completed, the bubbles in the paint will naturally dissipate, and it will be a two-component transparent finish. type fire retardant coating.

Example 2

(1) Dissolve 40g of polyphosphoric acid in 300ml of tetrahydrofuran, heat and stir until the polyphosphoric acid is evenly dissolved. 40 g of pentaerythritol was added to the system, and the temperature was raised to 90° C. for reaction. After 10 h of reaction, the solvent was evaporated using a rotary evaporator. The product was then grafted with 20g PEG300 under the reaction conditions of 120°C for 12 hours to obtain polyethylene glycol grafted polyphosphate;

(2) Make the prepared grafted polyphosphate into 50% aqueous solution, weigh 400g of water-based hexamethylol melamine formaldehyde resin, blend and stir for 30min, and wait for the bubbles in the paint to dissipate naturally after stirring. It is a two-component transparent finish type fire retardant coating.

Example 3

(1) Dissolve 45g of polyphosphoric acid in 250ml of dimethylformamide, heat and stir until the polyphosphoric acid is evenly dissolved. 32.5 g of pentaerythritol was added to the system, and the temperature was raised to 85° C. for reaction. After 8 hours of reaction, the solvent was evaporated using a rotary evaporator. The product was then grafted with 22.5g PEG400 under the reaction conditions of 110°C for 10 hours to obtain polyethylene glycol grafted polyphosphate;

(2) Make the prepared grafted polyphosphate into 50% aqueous solution, weigh 400g of water-based hexamethylol melamine formaldehyde resin, blend and stir for 30min, and wait for the bubbles in the paint to dissipate naturally after stirring. It is a two-component transparent finish type fire retardant coating.

Example 4

(1) Dissolve 50g of polyphosphoric acid in 200ml of dimethyl sulfoxide, heat and stir until the polyphosphoric acid is evenly dissolved. 25 g of pentaerythritol was added to the system, and the temperature was raised to 80° C. for reaction. After 6 hours of reaction, the solvent was evaporated using a rotary evaporator. The product was then grafted with 25g PEG600 under the reaction conditions of 100°C for 8 hours to obtain polyethylene glycol grafted polyphosphate;

(2) Make the prepared grafted polyphosphate into 66% ethanol solution, weigh 300g of water-based low-etherified melamine formaldehyde resin, blend and stir for 30min, and wait for the bubbles in the paint to dissipate naturally after stirring. It is a two-component transparent finish type fire retardant coating.

Example 5

(1) Dissolve 40g of polyphosphoric acid in 300ml of acetone, heat and stir until the polyphosphoric acid is evenly dissolved. 40 g of pentaerythritol was added to the system, and the temperature was raised to 90° C. for reaction. After 10 h of reaction, the solvent was evaporated using a rotary evaporator. The product was then grafted with 20g PPG800 under the reaction conditions of 120°C for 12 hours to obtain polyethylene glycol grafted polyphosphate;

(2) Make the prepared grafted polyphosphate into 66% ethanol solution, weigh 300g of water-based low-etherified melamine formaldehyde resin, blend and stir for 30min, and wait for the bubbles in the paint to dissipate naturally after stirring. It is a two-component transparent finish type fire retardant coating.

Example 6

(1) Dissolve 45g of polyphosphoric acid in 250ml of dioxane, heat and stir until the polyphosphoric acid is evenly dissolved. 32.5 g of pentaerythritol was added to the system, and the temperature was raised to 85° C. for reaction. After 8 hours of reaction, the solvent was evaporated using a rotary evaporator. The product was then grafted with 22.5g PEG1000 under the reaction conditions of 110°C for 10 hours to obtain polyethylene glycol grafted polyphosphate;

(2) Make the prepared grafted polyphosphate into 66% ethanol solution, weigh 300g of water-based low-etherified melamine formaldehyde resin, blend and stir for 30min, and wait for the bubbles in the paint to dissipate naturally after stirring. It is a two-component transparent finish type fire retardant coating.

Example 7

(1) Dissolve 50g of polyphosphoric acid in 200ml of dioxane, heat and stir until the polyphosphoric acid is evenly dissolved. Add 25g of pentaerythritol to the system, heat up to 90°C for reaction, and use a rotary evaporator to evaporate the solvent after 8 hours of reaction to obtain polyethylene glycol grafted polyphosphate;

(2) Mix the prepared grafted polyphosphate into 50% aqueous solution, weigh 400g of water-based urea-formaldehyde resin, and blend and stir for 30 minutes. After the stirring is completed, the bubbles in the coating will naturally dissipate, which is a two-component Transparent finish type fire retardant coating.

The basic properties of the two-component transparent finishing type fireproof coating prepared by each embodiment are shown in Table 2.

Table 2 Basic properties of two-component transparent finish fire retardant coatings

the Exterior Adhesion / grade Impact resistance /cm flexibility / level Flame-resistant time /min Example 1 transparent 1 25 2 17 Example 2 transparent 1 25 3 27 Example 3 transparent 1 25 2 20 Example 4 transparent 2 25 1 17 Example 5 transparent 2 25 2 28 Example 6 transparent 2 25 2 20 Example 7 transparent 1 25 1 18

Claims (5)

1. a preparation method of two-component transparent finish type fireproof coating, is characterized in that concrete steps are as follows: (1) Preparation of grafted polyphosphate Dissolve polyphosphoric acid in an appropriate amount of solvent, heat and stir until the polyphosphoric acid is uniformly dissolved; add pentaerythritol to the system, raise the temperature to 80-90°C for reaction, and use a rotary evaporator to evaporate the solvent after reacting for 6-10 hours; Carry out grafting reaction with polyethylene glycol under the reaction condition of 120°C, and the reaction time is 8-24 hours to obtain polyethylene glycol grafted polyphosphate; among them: polyphosphoric acid accounts for 40wt-50wt%, pentaerythritol accounts for 25wt-40wt %, polyethylene glycol accounts for 20wt% to 25wt%, and its total weight meets 100%, and the solvent used is 200wt% to 300wt% of the total weight; (2) Synthetic fire retardant coating The grafted polyphosphate ester obtained in step (1) is made into a solution, and blended and stirred with a water-based amino resin to obtain a two-component transparent finish type fireproof coating; the grafted polyphosphate ester and water-based amino resin The mass ratio is 1:2-1:4. 2. The preparation method of the two-component transparent finish type fireproof coating according to claim 1, characterized in that: the water-based amino resin is water-based hexamethylolmelamine-formaldehyde resin, water-based low-etherified melamine-formaldehyde resin or water-based One or more of urea-formaldehyde resins. 3. the preparation method of two-component transparent finishing type fireproof coating according to claim 1 is characterized in that: described solvent is dioxane, tetrahydrofuran, dimethylformamide, dimethyl sulfoxide or One of acetone. 4. The preparation method of two-component transparent finish type fireproof coating according to claim 1, characterized in that: the polyethylene glycol is PEG200, PEG300, PEG400, PEG600, PEG800, PEG1000, PEG1500 or PEG2000 A sort of. 5. the preparation method of two-component transparent finish type fireproof coating according to claim 1, is characterized in that, described graft polyphosphate ester solution is the ethanol of the graft polyphosphate ester of 50wt%～66wt%. solution or grafted polyphosphate aqueous solution.