Preparation method and application of phosphorus-containing hyperbranched polysiloxane modified impregnated paper

Abstract

The invention discloses a preparation method and application of phosphorus-containing hyperbranched polysiloxane modified impregnated paper, and the preparation method specifically comprises the following steps: step 1, dissolving phosphorus oxide and siloxane in a solvent, then fully stirring at 60-90 DEG C, and drying to obtain hyperbranched polysiloxane; 2, mixing the hyperbranched polysiloxane with a nano material, absolute ethyl alcohol and deionized water, heating in a water bath at 40-90 DEG C, fully stirring for 3-7 hours, performing vacuum filtration, cleaning and drying to constant weight to obtain phosphorus-containing hyperbranched polysiloxane; step 3, mixing the melamino-formaldehyde resin with the phosphorus-containing hyperbranched polysiloxane to obtain modified melamino-formaldehyde resin; and 4, immersing the raw paper of the impregnated paper into the modified melamine formaldehyde resin, and drying in a drying oven at 100-150 DEG C for 1-5 minutes to obtain the phosphorus-containing hyperbranched polysiloxane modified impregnated paper. The phosphorus-containing hyperbranched polysiloxane modified impregnated paper prepared by the invention has the advantages of good toughness, high strength and strong flame retardance.

Description

Technical Field

[0001] The field of the present invention is the technical field of impregnated paper preparation, and specifically relates to a preparation method and application of a phosphorus-containing hyperbranched polysiloxane-modified impregnated paper. Background Art

[0002] Impregnated paper is an important surface decoration material for furniture, wooden floors, and building panels, which plays a role in decorating and protecting the substrate. Among them, melamine formaldehyde (MF) impregnated paper dominates due to its excellent bonding strength and water resistance. However, MF impregnated paper is prone to cracking and difficult to resist the dimensional changes of the substrate caused by its inherent shrinkage and swelling due to dryness and wetness. At the same time, MF impregnated paper usually cannot meet the flame retardant requirements of practical applications, greatly increasing the possibility of safety risks and economic losses. Therefore, MF impregnated paper has two major defects: one is that it is brittle after curing and is prone to cracking due to dimensional changes of the substrate; the other is that it does not have flame retardancy itself and cannot meet the fire safety requirements. Summary of the Invention

[0003] The purpose of the present invention is to provide a preparation method and application of a phosphorus-containing hyperbranched polysiloxane-modified impregnated paper. The phosphorus-containing hyperbranched polysiloxane-modified impregnated paper prepared by the present invention has the advantages of good toughness, high strength, and strong flame retardancy.

[0004] The technical solution of the present invention: A preparation method of a phosphorus-containing hyperbranched polysiloxane-modified impregnated paper specifically includes the following steps:

[0005] Step 1: Dissolve 10-50 parts by mass of a phosphorus-based oxide and 10-50 parts by mass of a siloxane in 10-50 parts by mass of a solvent, and then stir thoroughly at 60°C - 90°C. After drying, hyperbranched polysiloxane is obtained;

[0006] Step 2: Mix 10-50 parts by mass of hyperbranched polysiloxane, 1-10 parts by mass of a nanomaterial, 50-100 parts by mass of absolute ethanol, and 50-100 parts by mass of deionized water, and then carry out water bath heating at 40-90°C and stir thoroughly for 3-7 hours. After vacuum filtration, washing, and drying to constant weight, phosphorus-containing hyperbranched polysiloxane is obtained;

[0007] Step 3: Mix melamine formaldehyde resin with phosphorus-containing hyperbranched polysiloxane to obtain a modified melamine formaldehyde resin;

[0008] Step 4: Immerse the base paper of the impregnated paper in the modified melamine formaldehyde resin, and dry it in an oven at 100-150°C for 1-5 minutes to obtain a phosphorus-containing hyperbranched polysiloxane-modified impregnated paper.

[0009] In the preparation method of the aforementioned phosphorus-containing hyperbranched polysiloxane-modified impregnated paper, the mass fraction of the phosphorus-based oxide is 30 parts; the mass fraction of the siloxane is 30 parts; the mass fraction of the solvent is 30 parts; the temperature for stirring the phosphorus-based oxide and the siloxane dissolved in the solvent is 70 °C.

[0010] In the preparation method of the aforementioned phosphorus-containing hyperbranched polysiloxane-modified impregnated paper, the phosphorus-based oxide includes 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and 1-(2,6-dimethylphenyl)-3-methyltriacyl-1,3,2-diazaphospholane-2-oxide; the siloxane includes 3-glycidoxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, tetramethoxysilane, methyltrimethoxysilane, and 3-(trimethoxysilyl)propyl methacrylate; the solvent is N,N-dimethylformamide.

[0011] In the preparation method of the aforementioned phosphorus-containing hyperbranched polysiloxane-modified impregnated paper, in step two, the mass fraction of the hyperbranched polysiloxane is 30 parts, the mass fraction of the nanomaterial is 6 parts, the mass fraction of absolute ethanol is 75 parts; the mass fraction of deionized water is 75 parts; the temperature of the water bath heating is 60 °C; the sufficient stirring time is 5 hours; the cleaning process is carried out with absolute ethanol 2-3 times; the drying process is carried out under vacuum at 60 °C.

[0012] In the preparation method of the aforementioned phosphorus-containing hyperbranched polysiloxane-modified impregnated paper, the nanomaterial includes nano-graphite, carbon nanotubes, cellulose nanofibers, and halloysite nanotubes.

[0013] In the preparation method of the aforementioned phosphorus-containing hyperbranched polysiloxane-modified impregnated paper, in step three, for the preparation of the melamine formaldehyde resin, first dissolve formaldehyde in deionized water, then adjust the pH of the formaldehyde solution to alkaline with NaOH, then heat the obtained solution to 50-70 °C, slowly add melamine to the formaldehyde solution, heat the mixed solution to 80-100 °C and react for about 1-2 hours, keep the pH value of the solution within the alkaline range, terminate the reaction, and cool the mixed solution to room temperature to obtain the melamine formaldehyde resin.

[0014] In the preparation method of the aforementioned phosphorus-containing hyperbranched polysiloxane-modified impregnated paper, the mass fraction of the phosphorus-containing hyperbranched polysiloxane is 4 parts; the mass fraction of the melamine formaldehyde resin is 30 parts.

[0015] In the preparation method of the aforementioned phosphorus-containing hyperbranched polysiloxane-modified impregnated paper, in step four, after the base paper of the impregnated paper is immersed in the modified melamine formaldehyde resin, use a roller to remove the excess modified melamine formaldehyde resin on the paper surface, and dry it in an oven at 120 °C for 3 minutes to obtain the phosphorus-containing hyperbranched polysiloxane-modified impregnated paper.

[0016] Application of the phosphorus-containing hyperbranched polysiloxane modified impregnated paper obtained by the foregoing preparation method in decorative materials and building materials.

[0017] In the foregoing application, the phosphorus-containing hyperbranched polysiloxane modified impregnated paper is bonded to the substrate of decorative materials and / or building materials and hot-pressed. The hot-pressing temperature is 150-200 °C, the pressure is 2-5 MPa, and the time is 20-50 seconds.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The phosphorus-containing hyperbranched polysiloxane modified impregnated paper prepared by the present invention has good toughness, high strength and strong flame retardancy, and can be applied to decorative and building materials required for fire prevention. In addition, the phosphorus-containing hyperbranched polysiloxane prepared by the present invention contains Si-O-C bonds, which can rotate freely, thereby endowing the modified melamine formaldehyde resin with more excellent toughness. The phosphorus-containing hyperbranched polysiloxane of the present invention has a highly branched three-dimensional structure and numerous molecular inner cavities, and can dissipate impact energy through the flexible deformation of molecular chain segments and cavitation effect, thereby improving the toughness of the phosphorus-containing hyperbranched polysiloxane modified impregnated paper. The phosphorus-containing hyperbranched polysiloxane of the present invention uses a silicon-containing main chain as the molecular skeleton and has excellent thermal stability; at the same time, it contains a phosphorus-based flame retardant component, which is beneficial to further improving the flame retardancy of the MF resin. The high-modulus nanostructure in the phosphorus-containing hyperbranched polysiloxane of the present invention can effectively endow the modified melamine formaldehyde resin with excellent mechanical strength and flame retardancy. Description of the Drawings

[0020] Figure 1 It is the stress-strain curve diagram of the melamine formaldehyde resin sample of the present invention;

[0021] Figure 2 It is the bar chart of the elongation at break of the melamine formaldehyde resin sample of the present invention;

[0022] Figure 3 It is the bending diagram of the impregnated paper of the melamine formaldehyde resin sample of the present invention;

[0023] Figure 4 It is the combustion diagram of the impregnated paper of the present invention. Detailed Embodiments

[0024] The present invention will be further described below in conjunction with the drawings and embodiments, but it is not used as a basis for limiting the present invention.

[0025] Example 1: A preparation method of a phosphorus-containing hyperbranched polysiloxane modified impregnated paper specifically includes the following steps:

[0026] Step 1: Dissolve 10 g of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and 10 g of 3-glycidoxypropyltrimethoxysilane by mass in 10 g of N,N-dimethylformamide (DMF), stir well at 60 °C, and then dry to obtain hyperbranched polysiloxane (HBPPSi).

[0027] Step 2: Mix 10 g of hyperbranched polysiloxane, 1 g of nano-graphite, 50 g of absolute ethanol and 50 g of deionized water by mass, add them to a three-necked flask equipped with a stir bar, heat in a water bath at 40 °C and stir well for 7 hours, perform vacuum filtration, and wash twice with absolute ethanol at the same time. Vacuum dry the filtrate at 60 °C to constant weight to obtain phosphorus-containing hyperbranched polysiloxane;

[0028] Step 3: Mix 30 g of melamine formaldehyde resin and 0.2 g of phosphorus-containing hyperbranched polysiloxane by mass, and further stir at room temperature for 30 minutes to obtain modified melamine formaldehyde resin;

[0029] In this step, the preparation of the melamine formaldehyde resin first dissolves formaldehyde in deionized water, then adjusts the pH of the formaldehyde solution to alkaline with NaOH, then heats the obtained solution to 50 °C, slowly adds melamine to the formaldehyde solution, heats the mixed solution to 80 °C and reacts for about 1 hour, keeps the pH value of the solution within the alkaline range, terminates the reaction, and cools the mixed solution to room temperature to obtain melamine formaldehyde resin.

[0030] Step 4: Immerse the base paper of the impregnated paper in melamine formaldehyde resin. After impregnation, use a roller to remove the excess melamine formaldehyde resin on the paper surface, and dry the impregnated paper in an oven at 100 °C for 5 minutes to obtain phosphorus-containing hyperbranched polysiloxane modified impregnated paper.

[0031] Example 2: A preparation method of phosphorus-containing hyperbranched polysiloxane modified impregnated paper, specifically including the following steps:

[0032] Step 1: Dissolve 20 g of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and 20 g of γ-methacryloxypropyltrimethoxysilane by mass in 20 g of N,N-dimethylformamide (DMF), stir well at 90 °C, and then dry to obtain hyperbranched polysiloxane (HBPPSi).

[0033] Step 2: Mix 20 g of hyperbranched polysiloxane, 4 g of carbon nanotubes, 80 g of absolute ethanol and 80 g of deionized water by mass, add them to a three-necked flask equipped with a stir bar, heat in a water bath at 90 °C and stir well for 3 hours, perform vacuum filtration, and wash twice with absolute ethanol at the same time. Vacuum dry the filtrate at 60 °C to constant weight to obtain phosphorus-containing hyperbranched polysiloxane;

[0034] Step 3: Mix 30 g of melamine formaldehyde resin and 0.4 g of phosphorus-containing hyperbranched polysiloxane by mass, and further stir at room temperature for 30 minutes to obtain a modified melamine formaldehyde resin;

[0035] In this step, the preparation of the melamine formaldehyde resin is to first dissolve formaldehyde in deionized water, then adjust the pH of the formaldehyde solution to alkaline with NaOH, and then heat the resulting solution to 50° C., slowly add melamine to the formaldehyde solution, heat the mixed solution to 80° C. and react for about 1 hour, the pH value of the solution is maintained within the alkaline range, the reaction is terminated, and the mixed solution is cooled to room temperature to obtain the melamine formaldehyde resin.

[0036] Step 4: Immerse the base paper of the impregnated paper in the modified melamine formaldehyde resin. After impregnation, use a roller to remove excess melamine formaldehyde resin on the surface of the paper, and dry the impregnated paper in an oven at 150° C. for 1 minute to obtain phosphorus-containing hyperbranched polysiloxane-modified impregnated paper.

[0037] Embodiment 3: A method for preparing phosphorus-containing hyperbranched polysiloxane-modified impregnated paper, comprising the following steps:

[0038] Step 1: Dissolve 50 g of 1-(2,6-dimethylphenyl)-3-triacyl-1,3,2-diazaphosphane-2-oxide and 50 g of tetramethoxysilane in 50 g of N,N-dimethylformamide (DMF) by mass, stir well at 80° C., and dry to obtain a hyperbranched polysiloxane (HBPPSi).

[0039] Step 2: 50 g of hyperbranched polysiloxane, 10 g of cellulose nanofibers, 100 g of anhydrous ethanol and 100 g of deionized water were mixed by mass, and then added into a three-necked flask with a stirring bar, heated in a water bath at 80° C. and stirred for 4 hours, and vacuum filtered, and washed with anhydrous ethanol for 3 times, and the filtrate was vacuum dried at 60° C. to constant weight to obtain phosphorus-containing hyperbranched polysiloxane;

[0040] Step 3: Mix 30 g of melamine formaldehyde resin and 0.6 g of phosphorus-containing hyperbranched polysiloxane by mass, and further stir at room temperature for 30 minutes to obtain a modified melamine formaldehyde resin;

[0041] In this step, for the preparation of the melamine formaldehyde resin, formaldehyde is first dissolved in deionized water, then the pH of the formaldehyde solution is adjusted to alkaline with NaOH, and then the obtained solution is heated to 50 °C. Melamine is slowly added to the formaldehyde solution, and the mixed solution is heated to 80 °C and reacted for about 1 hour while keeping the pH value of the solution within the alkaline range. The reaction is terminated, and the mixed solution is cooled to room temperature to obtain the melamine formaldehyde resin.

[0042] Step 4: Immerse the base paper of the impregnated paper into the modified melamine formaldehyde resin. After impregnation, use a roller to remove the excess melamine formaldehyde resin on the paper surface, and dry the impregnated paper in an oven at 110 °C for 4 minutes to obtain the phosphorus-containing hyperbranched polysiloxane modified impregnated paper.

[0043] Example 4: A preparation method of a phosphorus-containing hyperbranched polysiloxane modified impregnated paper specifically includes the following steps:

[0044] Step 1: Dissolve 30 g of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and 30 g of methyltrimethoxysilane in 30 g of N,N-dimethylformamide (DMF) by mass, stir well at 70 °C, and then dry to obtain hyperbranched polysiloxane (HBPPSi).

[0045] Step 2: Mix 30 g of hyperbranched polysiloxane, 5 g of halloysite nanotubes, 75 g of absolute ethanol and 75 g of deionized water by mass, add them to a three-necked flask with a stirrer, carry out water bath heating at 60 °C and stir well for 5 hours, perform vacuum filtration, and wash 3 times with absolute ethanol at the same time. Vacuum dry the filtered product at 60 °C to constant weight to obtain the phosphorus-containing hyperbranched polysiloxane.

[0046] Step 3: Mix 30 g of melamine formaldehyde resin and 0.8 g of phosphorus-containing hyperbranched polysiloxane by mass, and further stir at room temperature for 30 minutes to obtain the modified melamine formaldehyde resin.

[0047] In this step, for the preparation of the melamine formaldehyde resin, formaldehyde is first dissolved in deionized water, then the pH of the formaldehyde solution is adjusted to alkaline with NaOH, and then the obtained solution is heated to 50 °C. Melamine is slowly added to the formaldehyde solution, and the mixed solution is heated to 80 °C and reacted for about 1 hour while keeping the pH value of the solution within the alkaline range. The reaction is terminated, and the mixed solution is cooled to room temperature to obtain the melamine formaldehyde resin.

[0048] Step 4: Immerse the base paper of the impregnated paper into the modified melamine formaldehyde resin. After impregnation, use a roller to remove the excess melamine formaldehyde resin on the paper surface, and dry the impregnated paper in an oven at 130 °C for 2 minutes to obtain the phosphorus-containing hyperbranched polysiloxane modified impregnated paper.

[0049] Example 5: A preparation method of phosphorus-containing hyperbranched polysiloxane modified impregnated paper, specifically including the following steps:

[0050] Step 1: Dissolve 33 g of 1-(2,6-dimethylphenyl)-3-methyltrioxophosphorane-2-oxide and 33 g of 3-(trimethoxysilyl)propyl methacrylate in 33 g of N,N-dimethylformamide (DMF) by mass, stir well at 70 °C, and then dry to obtain hyperbranched polysiloxane (HBPPSi).

[0051] Step 2: Mix 36 g of hyperbranched polysiloxane, 4 g of carbon nanotubes, 60 g of absolute ethanol, and 60 g of deionized water by mass, add them to a three-necked flask with a stir bar, carry out water bath heating at 70 °C and stir well for 6 hours, perform vacuum filtration, and wash 3 times with absolute ethanol at the same time. Vacuum dry the filtered product at 60 °C until constant weight to obtain phosphorus-containing hyperbranched polysiloxane;

[0052] Step 3: Mix 30 g of melamine formaldehyde resin and 0.8 g of phosphorus-containing hyperbranched polysiloxane by mass, and further stir at room temperature for 30 minutes to obtain modified melamine formaldehyde resin;

[0053] In this step, for the preparation of the melamine formaldehyde resin, first dissolve formaldehyde in deionized water, then adjust the pH of the formaldehyde solution to alkaline with NaOH, then heat the obtained solution to 50 °C, slowly add melamine to the formaldehyde solution, heat the mixed solution to 80 °C and react for about 1 hour, keep the pH value of the solution within the alkaline range, terminate the reaction, and cool the mixed solution to room temperature to obtain melamine formaldehyde resin.

[0054] Step 4: Immerse the base paper of the impregnated paper into the modified melamine formaldehyde resin. After impregnation, use a roller to remove the excess melamine formaldehyde resin on the paper surface, and dry the impregnated paper in an oven at 130 °C for 2 minutes to obtain phosphorus-containing hyperbranched polysiloxane modified impregnated paper.

[0055] Example 6: An application of phosphorus-containing hyperbranched polysiloxane modified impregnated paper. Using particleboard as the substrate, the phosphorus-containing hyperbranched polysiloxane modified impregnated paper is laminated and hot-pressed with the substrate of decorative materials or building materials to make a phosphorus-containing hyperbranched polysiloxane modified impregnated paper decorative panel. The hot-pressing temperature is 150 - 200 °C, the pressure is 2 - 5 MPa, and the time is 20 - 50 seconds.

[0056] Comparative Example: Melamine and formaldehyde solution were reacted under alkaline conditions to produce melamine formaldehyde (MF) resin; in this step, the preparation of the melamine formaldehyde resin first dissolved formaldehyde in deionized water, then adjusted the pH of the formaldehyde solution to alkaline with NaOH, and then heated the obtained solution to 50 °C. Melamine was slowly added to the formaldehyde solution, and the mixed solution was heated to 80 °C and reacted for about 1 hour. The pH value of the solution was maintained within the alkaline range. The reaction was terminated, and the mixed solution was cooled to room temperature to obtain melamine formaldehyde resin. According to the mass parts, 30 g of melamine formaldehyde resin was further stirred at room temperature for 30 minutes; the base paper of the impregnated paper was immersed in the melamine formaldehyde resin. After impregnation, the excess melamine formaldehyde resin on the paper surface was removed with a roller, and the impregnated paper was dried in an oven at 130 °C for 2 minutes to obtain melamine formaldehyde impregnated paper.

[0057] The impregnated papers of Examples 1-4 and Comparative Example 1 were tested respectively according to the provisions of national standards GB / T1723-1993 and GB / T9724-2007. The test methods are as follows: ① The time for a certain amount of sample to flow out of a hole with a specified diameter at a certain temperature, expressed in seconds (s); ② A specified indicator electrode and a reference electrode were immersed in the same measured solution to form a primary battery, whose electromotive force was related to the pH value of the solution. By measuring the electromotive force of the primary battery, the pH value of the solution could be obtained. The viscosity and pH value data of the impregnated paper are shown in Table 1.

[0058] Table 1 Viscosity and pH value data of impregnated paper

[0059]

[0060]

[0061] It can be seen from the viscosity and pH data of Examples 1-4 and Comparative Example 1 in Table 1 that the modified melamine resin solution is close to neutral, with an average pH value of 7.5. Compared with the alkaline melamine formaldehyde resin (pH = 8.9), this neutral impregnating resin helps to reduce the corrosion of the base paper and extend the service life of the impregnated paper. Moreover, after adding phosphorus-containing hyperbranched polysiloxane, the viscosity of the MF resin (Tu-4 cup / 25 °C) increased to a certain extent. This may be because the phosphorus-containing hyperbranched polysiloxane formed hydrogen bonds with the melamine resin, increasing the intermolecular force, resulting in an increase in the viscosity of the modified melamine resin. However, the viscosity of the modified melamine resin still meets the production requirements.

[0062] Figure 1 It is the stress-strain curve diagram of the melamine formaldehyde resin samples of Examples 1-4 and Comparative Example 1. Figure 2Bar chart of the elongation at break of the melamine formaldehyde resin samples of Examples 1-4 and Comparative Example 1. The elongation at break of the unmodified MF impregnated paper is only 0.88%, and it is extremely prone to brittle fracture. This is attributed to the fact that the MF resin used for impregnation is brittle after curing, resulting in poor toughness of the impregnated paper. After adding phosphorus-containing hyperbranched polysiloxane, the elongation at break of the modified melamine resin impregnated paper has been significantly improved. When the addition amount of phosphorus-containing hyperbranched polysiloxane increases, the elongation at break of the impregnated paper made of the modified melamine resin can reach 1.54%. Compared with the pure melamine formaldehyde impregnated paper, its elongation at break has increased by 75%. In addition, while improving the toughness of the melamine formaldehyde resin impregnated paper, the phosphorus-containing hyperbranched polysiloxane also improves the tensile strength of the impregnated paper. When the addition amount of phosphorus-containing hyperbranched polysiloxane increases, the tensile strength of the modified melamine resin impregnated paper can be increased by up to 233% compared with the unmodified MF impregnated paper, reaching 18.44 MPa. This improvement is mainly attributed to the fact that halloysite nanotubes in the phosphorus-containing hyperbranched polysiloxane effectively improve the mechanical strength of the melamine resin through nano-reinforcement and inorganic hybridization effects.

[0063] In order to more intuitively display the toughness change of the impregnated paper before and after modification, a paper curling experiment was carried out. As Figure 3 shown, the unmodified melamine formaldehyde resin impregnated paper would crack brittlely after bending 90° around a 15 mm reel. After introducing phosphorus-containing hyperbranched polysiloxane into the melamine formaldehyde resin used for impregnation, the modified melamine resin impregnated paper can bypass a 4 mm reel without breaking. This finding confirms that the phosphorus-containing hyperbranched polysiloxane can improve the toughness of the melamine resin, thereby improving the flexibility of the obtained impregnated paper.

[0064] A combustion experiment was carried out on the impregnated paper before and after modification, as Figure 4 shown. During the 10-second combustion process, the paper impregnated with pure melamine formaldehyde has a longer flame length and a longer combustion time, mainly because the flame retardancy of the melamine formaldehyde impregnation resin is poor. After adding phosphorus-containing hyperbranched polysiloxane, the flame retardant performance of the impregnated paper made of the modified melamine is significantly improved, its flame length and combustion rate are significantly reduced, and it cannot continue to burn. It is worth noting that the modified melamine resin-impregnated paper goes out quickly during combustion and no flame appears. These results prove that after adding the modifier phosphorus-containing hyperbranched polysiloxane, the flame retardant performance of the impregnated paper is significantly improved, and the phosphorus-containing hyperbranched polysiloxane-modified impregnated paper after flame retardant modification can be applied to decorative and building materials required for fire prevention.

[0065] In summary, the phosphorus-containing hyperbranched polysiloxane-modified impregnated paper prepared by the present invention has good toughness, high strength and strong flame retardancy, and can be applied to decorative and building materials required for fire prevention. The phosphorus-containing hyperbranched polysiloxane prepared by the present invention contains Si-O-C bonds, which can rotate freely, thereby endowing the modified melamine formaldehyde resin with more excellent toughness. The phosphorus-containing hyperbranched polysiloxane of the present invention has a highly branched three-dimensional structure and numerous molecular inner cavities, and can dissipate impact energy through the flexible deformation of molecular chain segments and cavitation effect, thereby improving the toughness of the phosphorus-containing hyperbranched polysiloxane-modified impregnated paper. The phosphorus-containing hyperbranched polysiloxane of the present invention uses a silicon-containing main chain as a molecular skeleton and has excellent thermal stability; at the same time, it contains a phosphorus-based flame retardant component, which is beneficial to further improving the flame retardancy of the MF resin. The high-modulus nanostructure in the phosphorus-containing hyperbranched polysiloxane of the present invention can effectively endow the modified melamine formaldehyde resin with excellent mechanical strength and flame retardancy.

Claims

1. A method for preparing phosphorus-containing hyperbranched polysiloxane modified impregnated paper, characterized in that , specifically including the following steps: Step 1, dissolving 10-50 parts by weight of phosphorus oxide and 10-50 parts by weight of siloxane in 10-50 parts by weight of a solvent, then stirring at 60° C.-90° C., and drying to obtain a hyperbranched polysiloxane; Step 2: 10-50 parts by weight of hyperbranched polysiloxane, 1-10 parts by weight of nanomaterial, 50-100 parts by weight of anhydrous ethanol and 50-100 parts by weight of deionized water are mixed, heated in a water bath at 40-90° C. and stirred for 3-7 hours, and vacuum filtered, washed and dried to constant weight to obtain phosphorus-containing hyperbranched polysiloxane; Step 3, mixing melamine formaldehyde resin with phosphorus-containing hyperbranched polysiloxane to obtain modified melamine formaldehyde resin; Step 4: Immerse the base paper of the impregnated paper in the modified melamine formaldehyde resin, and dry it in an oven at 100-150° C. for 1-5 minutes to obtain the phosphorus-containing hyperbranched polysiloxane-modified impregnated paper.

2. The method for preparing the phosphorus-containing hyperbranched polysiloxane-modified impregnated paper according to claim 1, characterized in that: In step 1, the mass fraction of the phosphorus oxide is 30 parts; the mass fraction of the siloxane is 30 parts; the mass fraction of the solvent is 30 parts; and the temperature for dissolving the phosphorus oxide and the siloxane in the solvent and stirring is 70°C.

3. The method for preparing the phosphorus-containing hyperbranched polysiloxane-modified impregnated paper according to claim 1, characterized in that: The phosphorus-based oxides include 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and 1-(2,6-dimethylphenyl)-3-methyltriacyl-1,3,2-diazaphosphine-2-oxide; the siloxanes include 3-glycidyloxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, tetramethoxysilane, methyltrimethoxysilane and 3-(trimethoxymethylsilyl)propyl methacrylate; and the solvent is N,N-dimethylformamide.

4. The method for preparing the phosphorus-containing hyperbranched polysiloxane modified impregnated paper according to claim 1, characterized in that: Step 2: The mass part of the hyperbranched polysiloxane is 30 parts, the mass part of the nanomaterial is 5 parts, the mass part of the anhydrous ethanol is 75 parts; the mass part of the deionized water is 75 parts; the temperature of the water bath heating is 60°C; the sufficient stirring time is 5 hours; the washing process uses anhydrous ethanol for washing 2-3 times; and the drying process is carried out under vacuum at 60°C.

5. The method for preparing the phosphorus-containing hyperbranched polysiloxane modified impregnated paper according to claim 1, characterized in that: The nanomaterials include nanographite, carbon nanotubes, cellulose nanofibers and halloysite nanotubes.

6. The method for preparing the phosphorus-containing hyperbranched polysiloxane modified impregnated paper according to claim 1, characterized in that: In step 3, the preparation of the melamine formaldehyde resin comprises first dissolving formaldehyde in deionized water, then adjusting the pH of the formaldehyde solution to alkaline with NaOH, heating the resulting solution to 50-70° C., slowly adding melamine to the formaldehyde solution, heating the mixed solution to 80-100° C. and reacting for about 1-2 hours, wherein the pH value of the solution is maintained within the alkaline range, terminating the reaction, and cooling the mixed solution to room temperature to obtain the melamine formaldehyde resin.

7. The method for preparing the phosphorus-containing hyperbranched polysiloxane modified impregnated paper according to claim 1, characterized in that: The mass fraction of the phosphorus-containing hyperbranched polysiloxane is 4 parts; the mass fraction of the melamine formaldehyde resin is 30 parts.

8. The method for preparing the phosphorus-containing hyperbranched polysiloxane modified impregnated paper according to claim 1, characterized in that: Step 4: After the base paper of the impregnated paper is immersed in the modified melamine formaldehyde resin, the excess modified melamine formaldehyde resin on the surface of the paper is removed with a roller, and the paper is dried in an oven at 120° C. for 3 minutes to obtain the phosphorus-containing hyperbranched polysiloxane modified impregnated paper.

9. Application of the phosphorus-containing hyperbranched polysiloxane-modified impregnated paper obtained by the preparation method according to any one of claims 1 to 8 in decorative materials and building materials.

10. The use according to claim 9, characterized in that: The phosphorus-containing hyperbranched polysiloxane modified impregnated paper is attached to a base material of a decorative material and / or a building material and hot-pressed at a temperature of 150-200° C., a pressure of 2-5 MPa, and a time of 20-50 seconds.

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