Preparation Method and Application of a Low-Formaldehyde, High-Toughness and High-Temperature-Resistant Amino Resin

Abstract

The present invention relates to the field of impregnated film paper, specifically a preparation method and application of a low-formaldehyde, high-toughness and high-temperature-resistant amino resin. The prepared amino resin, together with organosilicon-modified polyvinyl alcohol and composite nano-silica, is used as a raw material to prepare impregnated film paper, obtaining impregnated film paper with green environmental protection, good water resistance, high flame retardancy and good abrasion resistance; polyvinyl alcohol is grafted with an epoxy group polymer containing double bonds and 3-glycidoxypropyltrimethoxysilane to obtain organosilicon-modified polyvinyl alcohol; nano-silica is modified with vinyl polydimethylsiloxane to obtain hydrophobic nano-silica. Using vinyl-modified nano-silica, dimethylaminoethyl methacrylate and an epoxy group polymer containing double bonds as raw materials, under the action of an initiator azobisisobutyronitrile, multi-active-site composite nano-silica is obtained by free radical polymerization.

Description

Technical Field

[0001] The present invention relates to the field of impregnated film paper, and specifically to a preparation method and application of a low-formaldehyde, high-toughness, and high-temperature-resistant amino resin. Background Art

[0002] Impregnated film paper usually refers to the one prepared by impregnating special paper in amino resin or phenolic resin, and it is a commonly used decorative material for furniture and home decoration materials. During the production process of impregnated film paper, melamine formaldehyde resin impregnated film paper has developed rapidly due to the characteristics of the resin used, such as colorless transparency and high bonding strength. However, it still has disadvantages such as poor hydrophobic performance, high brittleness, and poor storage stability. Most of the formaldehyde-free impregnated film papers on the market have problems such as poor bonding strength and insufficient surface physical and chemical energy.

[0003] At the same time, as a surface decoration material, impregnated film paper is flammable, which to a certain extent limits its application range. In order to strengthen environmental protection and improve the safety of materials, developing an impregnated film paper with low formaldehyde, good water resistance, flame retardancy, and wear resistance has great economic value and practical significance. Summary of the Invention

[0004] The purpose of the present invention is to provide a preparation method and application of a low-formaldehyde, high-toughness, and high-temperature-resistant amino resin to solve the problems in the prior art.

[0005] To solve the above technical problems, the present invention provides the following technical solutions:

[0006] A preparation method of a low-formaldehyde, high-toughness, and high-temperature-resistant amino resin, comprising the following steps:

[0007] Mix deionized water and formaldehyde, heat up to 60 - 65 °C, add melamine, keep the pH at 8.9 - 9.1, heat up to 90 °C and add an additive, keep warm at 95 - 98 °C for 1 - 2 h, add an auxiliary agent, keep warm at 82 - 87 °C for 10 - 20 min, cool down to 58 - 62 °C and add a solvent, then cool down to 28 - 32 °C, and discharge to obtain a low-formaldehyde, high-toughness, and high-temperature-resistant amino resin.

[0008] Further, the additive is one or a combination of p-toluenesulfonamide, methylguanamine, and caprolactam; the auxiliary agent is one or a combination of 1,4-butanediol, diethylene glycol, dipropylene glycol, and polyethylene glycol.

[0009] Further, the solvent is one or a combination of ethanol, methanol, and isopropanol.

[0010] Further, by mass, the raw material composition of the amino resin is: 90 - 95 parts of deionized water, 50 - 60 parts of formaldehyde, 58 - 65 parts of melamine, 18 - 20 parts of additive, 4 - 4.5 parts of auxiliary agent, and 1.5 - 2 parts of solvent.

[0011] Furthermore, an application of a low-formaldehyde, high-toughness and high-temperature-resistant amino resin is used for preparing impregnated film paper. The preparation of the impregnated film paper includes the following steps:

[0012] S1: Blend the amino resin and organosilicon-modified polyvinyl alcohol in a mass ratio of 4:1 as a composite impregnating solution;

[0013] S2: Put the base paper into the composite impregnating solution for impregnation treatment and then dry it to obtain a pretreated adhesive paper;

[0014] S3: Mix the organosilicon-modified polyvinyl alcohol and composite nano-silica to obtain a coating solution;

[0015] S4: Coat the coating solution on the pretreated adhesive paper and then dry it to obtain an impregnated film paper.

[0016] Furthermore, the process conditions for the impregnation treatment are as follows: the time is 35 - 45 s, and the impregnation amount is 88 - 98 g / m 2 ; the process conditions for the coating are as follows: the coating amount is 103 - 113 g / m 2 .

[0017] Furthermore, the mass ratio of the organosilicon-modified polyvinyl alcohol to the composite nano-silica is 21:(2 - 5).

[0018] Furthermore, the preparation of the organosilicon-modified polyvinyl alcohol includes the following steps:

[0019] Mix polyethylene glycol and deionized water, heat up to 85 - 95 °C and keep warm for 1 - 2 h, then cool down to 55 - 65 °C and add an epoxy polymer containing double bonds and 3-glycerol propyltrimethoxysilane, adjust the pH of the solution to 7 - 8, and keep warm for 2 - 3 h to obtain the organosilicon-modified polyvinyl alcohol.

[0020] Furthermore, the preparation of the composite nano-silica includes the following steps:

[0021] 1) Mix n-butanol and nano-silica, ultrasonically oscillate for 10 - 15 min, heat up to 78 - 82 °C and add vinyl polydimethylsiloxane, keep warm for 4 - 6 h, centrifuge, wash, dry, and grind to obtain modified nano-silica;

[0022] 2) Under a nitrogen atmosphere, mix the modified nano-silica, dimethylaminoethyl methacrylate, and an epoxy polymer containing double bonds, add a mixture of azobisisobutyronitrile, dichloromethane, and methanol, heat up to 65 - 75 °C and keep warm for 22 - 24 h, add dichloromethane, then centrifuge with petroleum ether, successively add dichloromethane and n-hexane, centrifuge, filter, wash, and freeze-dry to obtain the composite nano-silica.

[0023] Further, the preparation of the epoxy group polymer containing double bonds includes the following steps:

[0024] (1) Under a nitrogen atmosphere, magnolol, epichlorohydrin, and benzyltriethylammonium chloride are mixed, ultrasonically oscillated for 1 - 2 h, heated to 83 - 87 °C and kept warm for 3 - 4 h, cooled to 18 - 25 °C, sodium hydroxide solution is added, kept warm for 1 - 2 h, extracted with ethyl acetate, washed 3 - 5 times with saturated sodium chloride solution, and dried to obtain a magnolol-based epoxy monomer containing double bonds;

[0025] (2) Under a nitrogen atmosphere, DOPO, p-hydroxybenzaldehyde, and toluene are mixed, heated to 108 - 112 °C and kept warm for 1 - 2 h, filtered by suction, washed 3 - 5 times with absolute ethanol, and dried under reduced pressure to obtain a flame retardant intermediate containing hydroxyl groups;

[0026] (3) The magnolol-based epoxy monomer containing double bonds is heated to 128 - 132 °C, the flame retardant intermediate containing hydroxyl groups and butyltriphenylphosphonium bromide are added, kept warm for 3 - 4 h, cooled to 18 - 25 °C, dichloromethane is added, washed 3 - 5 times with deionized water, and dried to obtain an epoxy group polymer containing double bonds.

[0027] Advantages of the present invention:

[0028] The present invention provides a preparation method and application of a low-formaldehyde, high-toughness, and high-temperature-resistant amino resin. The prepared amino resin has low formaldehyde content, high toughness, and good high-temperature resistance. Using it together with organosilicon-modified polyvinyl alcohol and composite nano-silica as raw materials to prepare impregnated kraft paper, an impregnated kraft paper with green environmental protection, good water resistance, high flame retardancy, and good wear resistance is obtained.

[0029] In the present invention, through process and composition design, using formaldehyde and melamine as raw materials, using one or several of p-toluenesulfonamide, methylguanamine, and caprolactam as additives, and using one of 1,4-butanediol, diethylene glycol, dipropylene glycol, and polyethylene glycol as an auxiliary agent, a low-formaldehyde, high-toughness, and high-temperature-resistant amino resin is prepared; in order to improve the limited hydrophobicity and stability and the disadvantage of low content of free formaldehyde still existing when using pure amino resin as a raw material to prepare impregnated kraft paper, in the present invention, an amino resin and organosilicon-modified polyvinyl alcohol are blended as an impregnating stock solution, and organosilicon-modified polyvinyl alcohol and composite nano-silica are blended as a coating solution to form a layer-by-layer reinforced protective film on the surface of the base paper, and an environmentally friendly impregnated kraft paper is prepared, which has excellent water resistance, flame retardancy, and wear resistance at the same time.

[0030] In order to improve the flexibility, water resistance and flame retardancy of impregnated decorative papers and enhance the utilization value of amino resins, in the present invention, polyvinyl alcohol is grafted with an epoxy group polymer containing double bonds and 3-glycidoxypropyltrimethoxysilane to obtain organosilicon-modified polyvinyl alcohol, which is blended with amino resins to construct a complex crosslinked network, thereby improving the wettability of the composite impregnating solution and enhancing the bonding strength with the base paper. Meanwhile, Si-O bonds are introduced to effectively improve the flexibility of the impregnated decorative papers. The epoxy group polymer containing double bonds is prepared from magnolol, a biomass raw material containing a rigid biphenyl structure, allyl groups and phenolic hydroxyl groups in its molecular structure, and epichlorohydrin and benzyltriethylammonium chloride to obtain a magnolol-based epoxy monomer containing double bonds. Then, through the ring-opening of epoxy-hydroxy groups, it is grafted with a flame retardant intermediate containing hydroxyl groups prepared from the highly efficient phosphorus-based flame retardant DOPO (9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide) and p-hydroxybenzaldehyde, thereby greatly improving its flame retardancy and thermal stability.

[0031] In order to further improve the hydrophobicity, abrasion resistance and flame retardancy of impregnated decorative papers, nano-silica is introduced as a filler for the coating solution. To improve the uniformity of the dispersion of nano-silica in the coating solution, nano-silica is modified with vinyl polydimethylsiloxane to obtain hydrophobic modified nano-silica. To improve the bonding strength between the modified nano-silica and organosilicon-modified polyvinyl alcohol and prevent the problem of the modified nano-silica falling off from the coating layer formed by the coating solution, using the modified nano-silica, dimethylaminoethyl methacrylate and an epoxy group polymer containing double bonds as raw materials, under the action of the initiator azobisisobutyronitrile, through free radical polymerization, a composite nano-silica with multiple active sites is obtained, thereby improving its compatibility with organosilicon-modified polyvinyl alcohol and endowing the impregnated decorative papers with long-lasting excellent water resistance, flame retardancy and abrasion resistance, thus increasing the service life of the impregnated decorative papers. Detailed implementation mode

[0032] The following will clearly and completely describe the technical solutions in the present invention in combination with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0033] It should be noted that if there are directional indications in the embodiments of the present invention, such as up, down, left, right, front, and back, these directional indications are only used to explain the relative positional relationship and movement conditions between components in a specific posture. If the specific posture changes, the directional indications will also change accordingly. In addition, the technical solutions between various embodiments can be combined with each other, but it must be based on the ability of those skilled in the art to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0034] The technical solutions of the present invention will be further described in detail below in conjunction with specific embodiments. It should be understood that the following embodiments are only used to explain the present invention and are not used to limit the present invention.

[0035] Embodiment 1: Application of a low-formaldehyde, high-toughness, high-temperature-resistant amino resin in the preparation of impregnated film paper. The preparation of the impregnated film paper includes the following steps:

[0036] S1: Blend amino resin and organosilicon-modified polyvinyl alcohol in a mass ratio of 4:1 to obtain a composite impregnating solution.

[0037] The preparation method of the amino resin includes the following steps:

[0038] Mix deionized water and formaldehyde, heat up to 60°C, add melamine, keep the pH at 8.9, heat up to 90°C, add an additive, keep warm at 95°C for 2 h, add an auxiliary agent, keep warm at 82°C for 20 min, cool down to 58°C, add a solvent, cool down to 28°C, and discharge to obtain a low-formaldehyde, high-toughness, high-temperature-resistant amino resin.

[0039] The additive is methylguanamine; the auxiliary agent is 1,4-butanediol; the solvent is ethanol; by mass fraction, the raw material composition of the amino resin is: 90 parts of deionized water, 50 parts of formaldehyde, 58 parts of melamine, 18 parts of additive, 4 parts of auxiliary agent, and 1.5 parts of solvent.

[0040] The preparation of the organosilicon-modified polyvinyl alcohol includes the following steps:

[0041] Mix 1 g of polyethylene glycol and 99 mL of deionized water, heat up to 85°C and keep warm for 2 h, cool down to 55°C, add 5 g of an epoxy polymer containing double bonds and 3 g of 3-glycidoxypropyltrimethoxysilane, adjust the pH of the solution to 7, and keep warm for 2 h to obtain organosilicon-modified polyvinyl alcohol.

[0042] The preparation of the epoxy polymer containing double bonds includes the following steps:

[0043] (1) Under a nitrogen atmosphere, 8.1 g of magnolol, 2.83 g of epichlorohydrin, and 0.5 g of benzyltriethylammonium chloride were mixed, ultrasonically oscillated for 1 h, heated to 83 °C and kept warm for 4 h, cooled to 18 °C, 100 mL of a 40% sodium hydroxide solution by mass was added, kept warm for 1 h, extracted with ethyl acetate, washed 3 times with saturated sodium chloride solution, and dried to obtain a magnolol-based epoxy monomer containing a double bond;

[0044] (2) Under a nitrogen atmosphere, 11.9 g of DOPO, 6.1 g of p-hydroxybenzaldehyde, and 150 mL of toluene were mixed, heated to 108 °C and kept warm for 2 h, filtered by suction, washed 3 times with absolute ethanol, and dried under reduced pressure to obtain a flame retardant intermediate containing a hydroxyl group;

[0045] (3) 25 g of the magnolol-based epoxy monomer containing a double bond was heated to 128 °C, 12 g of the flame retardant intermediate containing a hydroxyl group and 0.25 g of butyltriphenylphosphonium bromide were added, kept warm for 3 h, cooled to 18 °C, 100 mL of dichloromethane was added, washed 3 times with deionized water, and dried to obtain an epoxy group polymer containing a double bond;

[0046] S2: The base paper was put into a composite impregnating solution for impregnation treatment and dried to obtain a pretreated adhesive paper;

[0047] The process conditions for the impregnation treatment were: temperature 40 °C, time 45 s, impregnation amount 92 g / m 2 ;

[0048] S3: Organosilicon-modified polyvinyl alcohol and composite nano-silica were mixed to obtain a coating solution;

[0049] The mass ratio of the organosilicon-modified polyvinyl alcohol to the composite nano-silica was 21:2;

[0050] The preparation of the composite nano-silica included the following steps:

[0051] 1) 100 g of n-butanol and 5 g of nano-silica were mixed, ultrasonically oscillated for 10 min, heated to 78 °C, vinyl polydimethylsiloxane was added, kept warm for 4 h, centrifuged, washed, dried, and ground to obtain modified nano-silica;

[0052] 2) Under a nitrogen atmosphere, 5 g of the modified nano-silica, 4 g of dimethylaminoethyl methacrylate, and 10 g of the epoxy group polymer containing a double bond were mixed, 0.1 g of azobisisobutyronitrile, 40 mL of dichloromethane, and 40 mL of methanol mixture were added, heated to 65 °C and kept warm for 24 h, 80 mL of dichloromethane was added, then centrifuged with petroleum ether, 80 mL of dichloromethane was added, 60 mL of n-hexane was added, centrifuged, filtered, washed, and freeze-dried to obtain the composite nano-silica;

[0053] The coating process conditions are as follows: the coating amount is 103 g / m 2 ;

[0054] S4: Coating the coating liquid on the pretreated adhesive paper, and drying to obtain an impregnated adhesive film paper.

[0055] Example 2: The application of a low-formaldehyde, high-toughness and high-temperature-resistant amino resin in the preparation of an impregnated adhesive film paper. The preparation of the impregnated adhesive film paper includes the following steps:

[0056] S1: Blending amino resin and organosilicon-modified polyvinyl alcohol in a mass ratio of 4:1 as a composite impregnating liquid;

[0057] The preparation method of the amino resin includes the following steps:

[0058] Mix deionized water and formaldehyde, heat up to 63 °C, add melamine, keep the pH at 9, heat up to 90 °C and add an additive, keep warm at 96 °C for 1.5 h, add an auxiliary agent, keep warm at 85 °C for 15 min, cool down to 60 °C and add a solvent, then cool down to 30 °C and discharge to obtain a low-formaldehyde, high-toughness and high-temperature-resistant amino resin;

[0059] The additive is methylguanamine; the auxiliary agent is 1,4-butanediol; the solvent is ethanol; by mass fraction, the raw material composition of the amino resin is: 93 parts of deionized water, 55 parts of formaldehyde, 62 parts of melamine, 19 parts of additive, 4.2 parts of auxiliary agent, and 1.8 parts of solvent;

[0060] The preparation of the organosilicon-modified polyvinyl alcohol includes the following steps:

[0061] Mix 1 g of polyethylene glycol and 99 mL of deionized water, heat up to 90 °C and keep warm for 1.5 h, cool down to 60 °C and add 5 g of an epoxy polymer containing double bonds and 3 g of 3-glycidoxypropyltrimethoxysilane, adjust the pH of the solution to 7.5, and keep warm for 2.5 h to obtain organosilicon-modified polyvinyl alcohol;

[0062] The preparation of the epoxy polymer containing double bonds includes the following steps:

[0063] (1) Under a nitrogen atmosphere, mix 8.1 g of magnolol, 2.83 g of epichlorohydrin, and 0.5 g of benzyltriethylammonium chloride, ultrasonically oscillate for 1.5 h, heat up to 85 °C and keep warm for 3.5 h, cool down to 20 °C, add 100 mL of a 40% sodium hydroxide solution by mass fraction, keep warm for 1.5 h, extract with ethyl acetate, wash 4 times with saturated sodium chloride solution, and dry to obtain a magnolol-based epoxy monomer containing double bonds;

[0064] (2) Under a nitrogen atmosphere, 11.9 g of DOPO, 6.1 g of p-hydroxybenzaldehyde, and 150 mL of toluene were mixed, heated to 110 °C and kept warm for 1.5 h, filtered by suction, washed 4 times with absolute ethanol, and dried under reduced pressure to obtain a flame retardant intermediate containing hydroxyl groups;

[0065] (3) 25 g of magnolol-based epoxy monomer containing double bonds was heated to 130 °C, 12 g of the flame retardant intermediate containing hydroxyl groups and 0.25 g of butyltriphenylphosphonium bromide were added, kept warm for 3.5 h, cooled to 20 °C, 100 mL of dichloromethane was added, washed 4 times with deionized water, and dried to obtain an epoxy polymer containing double bonds;

[0066] S2: The base paper was put into the composite impregnating solution for impregnation treatment, and dried to obtain a pretreated adhesive paper;

[0067] The process conditions for the impregnation treatment were: temperature 45 °C, time 40 s, impregnation amount 92 g / m 2 ;

[0068] S3: Organosilicon-modified polyvinyl alcohol and composite nano-silica were mixed to obtain a coating solution;

[0069] The mass ratio of organosilicon-modified polyvinyl alcohol to composite nano-silica was 21:3;

[0070] The preparation of the composite nano-silica included the following steps:

[0071] 1) 100 g of n-butanol and 5 g of nano-silica were mixed, ultrasonically oscillated for 12 min, heated to 80 °C, vinyl polydimethylsiloxane was added, kept warm for 5 h, centrifuged, washed, dried, and ground to obtain modified nano-silica;

[0072] 2) Under a nitrogen atmosphere, 5 g of modified nano-silica, 4 g of dimethylaminoethyl methacrylate, and 10 g of the epoxy polymer containing double bonds were mixed, 0.1 g of azobisisobutyronitrile, 40 mL of dichloromethane, and 40 mL of methanol mixture were added, heated to 70 °C and kept warm for 23 h, 80 mL of dichloromethane was added, then centrifuged with petroleum ether, 80 mL of dichloromethane was added, 60 mL of n-hexane was added, centrifuged, filtered, washed, and freeze-dried to obtain composite nano-silica;

[0073] The process conditions for coating were: coating amount 109 g / m 2 ;

[0074] S4: The coating solution was coated on the pretreated adhesive paper and dried to obtain an impregnated adhesive film paper.

[0075] Example 3: The application of a low-formaldehyde, high-toughness and high-temperature-resistant amino resin in the preparation of an impregnated adhesive film paper. The preparation of the impregnated adhesive film paper included the following steps:

[0076] S1: Blend amino resin and organosilicon-modified polyvinyl alcohol in a mass ratio of 4:1 as a composite impregnating solution;

[0077] Preparation method of amino resin, comprising the following steps:

[0078] Mix deionized water and formaldehyde, heat up to 65 °C, add melamine, keep the pH at 9.1, heat up to 90 °C and add an additive, keep warm at 98 °C for 1 h, add an auxiliary agent, keep warm at 87 °C for 10 min, cool down to 58 °C and add a solvent, cool down to 32 °C, and discharge to obtain a low-formaldehyde, high-toughness and high-temperature-resistant amino resin;

[0079] The additive is methylguanamine; the auxiliary agent is 1,4-butanediol; the solvent is ethanol; by mass fraction, the raw material composition of the amino resin is: 95 parts of deionized water, 60 parts of formaldehyde, 65 parts of melamine, 20 parts of additive, 4.5 parts of auxiliary agent, and 2 parts of solvent;

[0080] The preparation of the organosilicon-modified polyvinyl alcohol comprises the following steps:

[0081] Mix 1 g of polyethylene glycol and 99 mL of deionized water, heat up to 95 °C and keep warm for 1 h, cool down to 65 °C and add 5 g of a double-bond-containing epoxy polymer and 3 g of 3-glycidoxypropyltrimethoxysilane, adjust the pH of the solution to 8, and keep warm for 3 h to obtain organosilicon-modified polyvinyl alcohol;

[0082] The preparation of the double-bond-containing epoxy polymer comprises the following steps:

[0083] (1) Under a nitrogen atmosphere, mix 8.1 g of magnolol, 2.83 g of epichlorohydrin, and 0.5 g of benzyltriethylammonium chloride, ultrasonically oscillate for 2 h, heat up to 87 °C and keep warm for 3 h, cool down to 25 °C, add 100 mL of a 40% sodium hydroxide solution by mass fraction, keep warm for 2 h, extract with ethyl acetate, wash 5 times with saturated sodium chloride solution, and dry to obtain a magnolol-based epoxy monomer containing double bonds;

[0084] (2) Under a nitrogen atmosphere, mix 11.9 g of DOPO, 6.1 g of p-hydroxybenzaldehyde, and 150 mL of toluene, heat up to 112 °C and keep warm for 1 h, filter by suction, wash 5 times with absolute ethanol, and dry under reduced pressure to obtain a flame retardant intermediate containing hydroxyl groups;

[0085] (3) Heat 25 g of the double-bond-containing magnolol-based epoxy monomer to 132 °C, add 12 g of the flame retardant intermediate containing hydroxyl groups and 0.25 g of butyltriphenylphosphonium bromide, keep warm for 4 h, cool to 25 °C, add 100 mL of dichloromethane, wash 5 times with deionized water, and dry to obtain a double-bond-containing epoxy polymer;

[0086] S2: Put the base paper into the composite impregnating solution for impregnation treatment, and then dry it to obtain the pretreated adhesive paper;

[0087] The process conditions for the impregnation treatment are as follows: the temperature is 50 °C, the time is 35 s, and the impregnation amount is 92 g / m 2 ;

[0088] S3: Mix silicone-modified polyvinyl alcohol and composite nano-silica to obtain a coating solution;

[0089] The mass ratio of silicone-modified polyvinyl alcohol to composite nano-silica is 21:5;

[0090] The preparation of the composite nano-silica includes the following steps:

[0091] 1) Mix 100 g of n-butanol and 5 g of nano-silica, ultrasonically oscillate for 15 min, heat up to 82 °C, add vinyl polydimethylsiloxane, keep warm for 6 h, centrifuge, wash, dry, and grind to obtain modified nano-silica;

[0092] 2) Under a nitrogen atmosphere, mix 5 g of modified nano-silica, 4 g of dimethylaminoethyl methacrylate, and 10 g of epoxy polymer containing double bonds, add 0.1 g of azobisisobutyronitrile, 40 mL of dichloromethane, and 40 mL of methanol mixture, heat up to 75 °C and keep warm for 22 h, add 80 mL of dichloromethane, then centrifuge with petroleum ether, add 80 mL of dichloromethane, add 60 mL of n-hexane, centrifuge, filter, wash, and freeze-dry to obtain composite nano-silica;

[0093] The process conditions for coating are: the coating amount is 113 g / m 2 ;

[0094] S4: Coat the coating solution on the pretreated adhesive paper and dry it to obtain an impregnated adhesive film paper.

[0095] Comparative Example 1: Taking Example 3 as the control group, replace the composite nano-silica with nano-silica, and the other processes are normal.

[0096] Comparative Example 2: Taking Example 3 as the control group, replace the silicone-modified polyvinyl alcohol with polyvinyl alcohol, and the other processes are normal.

[0097] Comparative Example 3: Taking Example 3 as the control group, do not prepare the epoxy polymer containing double bonds, and the other processes are normal.

[0098] Raw material sources (only for demonstration examples):

[0099] Base paper (recycled kraft paper, thickness 0.2 mm): Chengdu Zhuyuan Sheng Paper Co., Ltd.; Melamine 1: Shandong Xinheng Chemical Co., Ltd.; Vinyl polydimethylsiloxane 53529-60-5: Hubei Jusheng Technology Co., Ltd.; Methylguanamine A106445, 1,4-Butanediol B110391, Polyethylene glycol P103719, 3-Glycerol propyltrimethoxysilane G107576, Magnolol M111378, Epichlorohydrin E108182, Benzyltriethylammonium chloride B108417, DOP O102416, p-Hydroxybenzaldehyde H100420, Butyltriphenylphosphonium bromide B107826, Nano-silica S104596, Dimethylaminoethyl methacrylate D111129, 2,2'-Azobis(2-methylpropionitrile) A434183: Aladdin Reagent; Formic acid, Ethanol, Sodium hydroxide, Ethyl acetate, Sodium chloride, Toluene, Dichloromethane, n-Butanol, n-Hexane, analytically pure: Reagents of Sinopharm Chemical Reagent Co., Ltd.

[0100] Performance test: The impregnated film papers prepared in the examples and comparative examples were tested:

[0101] Flammability: UL-94 vertical burning rating test was carried out; Hydrophobicity: Test was carried out using a contact angle tester with 4 μL deionized water droplets; Abrasion resistance: The sample was placed on 200-mesh sandpaper with a 10 g weight pressed on it, pulled at a speed of 2 mm / min, and one cycle was 10 cm. After 20 cycles, the water contact angle was tested, and the change rate was characterized compared with the initial contact angle. Less than 2% (including 2%) was excellent, otherwise it was unqualified; The results are shown in Table 1 below;

[0102] Table 1

[0103] Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Flame retardant grade V-0 V-0 V-0 V-1 V-1 V-2 Water contact angle (°) 132.8 132.9 133.1 126.2 128.7 121.5 Wear resistance Excellent Excellent Excellent Unqualified Unqualified Unqualified

[0104] The present invention provides a preparation method and application of a low-formaldehyde, high-toughness and high-temperature-resistant amino resin. The prepared amino resin has low formaldehyde, high toughness and good high-temperature resistance. Together with organosilicon-modified polyvinyl alcohol and composite nano-silica, it is used as a raw material to prepare an impregnated film paper, obtaining an impregnated film paper with green environmental protection, good water resistance, high flame retardancy and good abrasion resistance.

[0105] Example 3 was compared with Comparative Example 1 and Comparative Example 3. In order to further improve the hydrophobicity, wear resistance and flame retardancy of the impregnated film paper, nano-silica was introduced as a filler for the coating solution. In order to improve the uniformity of the dispersion of nano-silica in the coating solution, the nano-silica was modified. Vinyl polydimethylsiloxane was used to modify the nano-silica to obtain hydrophobic modified nano-silica. In order to improve the bonding strength between the modified nano-silica and the silicone-modified polyvinyl alcohol and prevent the problem of the modified nano-silica falling off from the coating layer formed by the coating solution, vinyl-modified nano-silica, dimethylaminoethyl methacrylate, and a double-bond-containing epoxy polymer were used as raw materials. Under the action of the initiator azobisisobutyronitrile, free radical polymerization was used to obtain composite nano-silica with multiple active sites, thereby improving its compatibility with the silicone-modified polyvinyl alcohol and endowing the impregnated film paper with long-lasting and excellent water resistance, flame retardancy and wear resistance, thereby improving the service life of the impregnated film paper.

[0106] Example 3 was compared with Comparative Example 2 and Comparative Example 3. In order to improve the flexibility, water resistance and flame retardancy of the impregnated film paper and enhance the utilization value of the amino resin, in the present invention, polyvinyl alcohol was grafted with a double-bond-containing epoxy polymer and 3-glycidoxypropyltrimethoxysilane to obtain silicone-modified polyvinyl alcohol, which was blended with the amino resin to construct a complex cross-linked network, thereby improving the wettability of the composite impregnating solution and the bonding strength with the base paper; at the same time, Si-O bonds were introduced to effectively improve the flexibility of the impregnated film paper; the double-bond-containing epoxy polymer was prepared from magnolol, a biomass raw material containing a rigid biphenyl structure, allyl groups and phenolic hydroxyl groups in its molecular structure, and epichlorohydrin and benzyltriethylammonium chloride to prepare a double-bond-containing magnolol-based epoxy monomer, and then the epoxy-hydroxyl ring opening was used to graft a hydroxyl-containing flame retardant intermediate prepared from the high-efficiency phosphorus-based flame retardant DOPO (9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide) and p-hydroxybenzaldehyde, thereby greatly improving its flame retardancy and thermal stability.

[0107] The above are only the embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. All equivalent structural transformations made using the description of the present invention under the inventive concept of the present invention, or direct / indirect applications in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. An application of a low-formaldehyde, high-toughness, high-temperature-resistant amino resin, characterized in that: The following steps are involved: Deionized water and formaldehyde are mixed, heated to 60-65°C, melamine is added, the pH is maintained at 8.9-9.1, heated to 90°C, additives are added, the temperature is kept at 95-98°C for 1-2 hours, auxiliary agents are added, the temperature is kept at 82-87°C for 10-20 minutes, the temperature is lowered to 58-62°C, solvents are added, the temperature is lowered to 28-32°C, and the material is discharged to obtain a low-aldehyde, high-toughness, high-temperature-resistant amino resin; The low-formaldehyde, high-toughness, high-temperature-resistant amino resin is used to prepare impregnated film paper, and the preparation of the impregnated film paper includes the following steps: S1: amino resin and silicone-modified polyethylene glycol are mixed in a mass ratio of 4:1 to form a composite impregnation liquid; S2: putting the base paper into the composite impregnation liquid for impregnation treatment, and drying to obtain the pre-treated adhesive paper; S3: mixing organosilicon-modified polyethylene glycol and composite nano-silicon dioxide to obtain a coating liquid; S4: coating the coating liquid on the pre-treated adhesive paper, and drying to obtain an impregnated adhesive film paper; The preparation of the composite nano-silicon dioxide comprises the following steps: 1) mixing n-butanol and nano-silica, ultrasonically vibrating for 10-15 minutes, heating to 78-82° C., adding vinyl polydimethylsiloxane, keeping the temperature for 4-6 hours, centrifuging, washing, drying, and grinding to obtain modified nano-silica; 2) In a nitrogen atmosphere, the modified nano-silica, dimethylaminoethyl methacrylate, and epoxy polymer containing double bonds are mixed, azobisisobutyronitrile, dichloromethane, and methanol mixed solution are added, the temperature is raised to 65-75° C. and kept warm for 22-24 hours, dichloromethane is added, and then centrifuged with petroleum ether, dichloromethane and n-hexane are added in sequence, centrifuged, filtered, washed, and freeze-dried to obtain composite nano-silica; The preparation of the organosilicon-modified polyethylene glycol comprises the following steps: Mix polyethylene glycol and deionized water, raise the temperature to 85-95°C and keep it for 1-2 hours, cool it to 55-65°C, add epoxy polymer containing double bonds and 3-glycidyloxypropyltrimethoxysilane, adjust the pH of the solution to 7-8, keep it for 2-3 hours, and obtain silicone-modified polyethylene glycol; The additive is one or more of p-toluenesulfonamide, methylguanamine, and caprolactam; the auxiliary agent is one or more of 1,4-butanediol, diethylene glycol, dipropylene glycol, and polyethylene glycol; In the preparation of the impregnated film paper, the mass ratio of organosilicon-modified polyethylene glycol to composite nano-silicon dioxide is 21:(2-5); The preparation of the epoxy polymer containing double bonds comprises the following steps: (1) Under a nitrogen atmosphere, magnolol, epichlorohydrin, and benzyltriethylammonium chloride are mixed, ultrasonically vibrated for 1-2 hours, heated to 83-87° C. and kept warm for 3-4 hours, cooled to 18-25° C., sodium hydroxide solution is added, kept warm for 1-2 hours, extracted with ethyl acetate, washed with saturated sodium chloride solution for 3-5 times, and dried to obtain a magnolol-based epoxy monomer containing a double bond; (2) Under a nitrogen atmosphere, DOPO, p-hydroxybenzaldehyde and toluene are mixed, heated to 108-112° C. and kept warm for 1-2 hours, filtered, washed with anhydrous ethanol for 3-5 times, and dried under reduced pressure to obtain a flame retardant intermediate containing a hydroxyl group; (3) heating the magnolia phenol-based epoxy monomer containing a double bond to 128-132° C., adding a flame retardant intermediate containing a hydroxyl group and butyl triphenylphosphonium bromide, keeping the temperature for 3-4 hours, cooling to 18-25° C., adding dichloromethane, washing with deionized water for 3-5 times, and drying to obtain an epoxy polymer containing a double bond.

2. The use of a low-formaldehyde, high-toughness, high-temperature-resistant amino resin according to claim 1, characterized in that: The solvent is one or a combination of ethanol, methanol and isopropanol.

3. The use of a low-aldehyde, high-toughness, high-temperature-resistant amino resin according to claim 1, characterized in that: The raw material composition of the amino resin is as follows, by weight: 90-95 parts of deionized water, 50-60 parts of formaldehyde, 58-65 parts of melamine, 18-20 parts of additives, 4-4.5 parts of auxiliary agents, and 1.5-2 parts of solvents.

4. The use of a low-formaldehyde, high-toughness, high-temperature-resistant amino resin according to claim 1, characterized in that: In the preparation of impregnated film paper, the process conditions of impregnation treatment are: temperature 40-50℃, time 35-45s, impregnation amount 88-98g / m 2 ; The coating process conditions are: coating amount is 103-113g / m 2 .