A preparation process for improving the moisture resistance of impregnated paper

Abstract

The application relates to the technical field of impregnated paper production, in particular to a preparation process for improving the moisture-proof performance of impregnated paper, S1, glue impregnation: original paper is impregnated in short-fiber modified melamine glue for 30-60 min, and then dried to obtain melamine impregnated paper; S2, emulsion coating: 5-10 parts by weight of modified nano-silica emulsion, 1-3 parts by weight of hexadecyl trimethoxysilane and 30-50 parts by weight of polyurethane emulsion are uniformly stirred, and then double-sided coating is carried out, and then drying is carried out. In the glue impregnation step, the original paper is impregnated in short-fiber modified melamine glue, and in the emulsion coating step, the modified nano-silica emulsion and the polyurethane emulsion are uniformly stirred, and then double-sided coating is carried out, physical moisture-proof and chemical moisture-proof are combined with each other, an inner-to-outer upper-layer moisture-proof system is adopted, and the moisture-proof performance of the impregnated paper is effectively improved.

Description

Technical Field

[0001] This invention relates to the field of impregnated paper production technology, specifically to a preparation process for improving the moisture-proof performance of impregnated paper. Background Technology

[0002] Impregnated paper is made primarily from specially produced base paper, which is impregnated with synthetic resin and then dried. It is then applied to a particleboard substrate and bonded together under heat to form a decorative facing paper. With the improvement of living standards, consumers have increasingly higher performance requirements for impregnated paper, especially its moisture-proof properties.

[0003] For example, Chinese patent CN110042701B discloses a moisture-proof and flame-retardant impregnated paper and its preparation method, including a base paper layer, a moisture-proof layer adhered to the upper surface of the base paper layer, a flame-retardant adhesive film layer adhered to the upper surface of the moisture-proof layer, and a wear-resistant layer adhered to the upper surface of the flame-retardant adhesive film layer; the flame-retardant adhesive film layer is obtained by printing a layer of composite flame-retardant material on the upper surface of the moisture-proof layer; the composite flame-retardant material includes the following raw materials in parts by weight: 20-30 parts of phosphorus-nitrogen composite flame retardant, 10-15 parts of melamine A, 5-10 parts of PVC resin, 20-30 parts of MF prepolymer, 5-15 parts of ZnSn(OH)6, 1-5 parts of nano TiO2, 1-5 parts of urea A, and 1-5 parts of PVP. This moisture-proof and flame-retardant impregnated paper has excellent moisture-proof and flame-retardant properties by setting a moisture-proof layer on the base paper layer. However, existing impregnated paper has poor moisture resistance and is easily damaged by moisture during long-term storage, which greatly affects the service life of the impregnated paper and greatly reduces its practicality. Therefore, this invention provides a preparation process to improve the moisture resistance of impregnated paper. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a preparation process for improving the moisture-proof performance of impregnated paper, solving the problem that existing impregnated paper has poor moisture-proof performance and is easily damaged by moisture during long-term storage, which greatly affects the service life and practicality of impregnated paper.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A preparation process for improving the moisture-proof properties of impregnated paper specifically includes the following steps:

[0007] S1. Glue impregnation: Immerse the base paper in modified melamine glue for 30-60 minutes, then dry to obtain melamine-impregnated paper;

[0008] S2. Coating emulsion: Mix 5-10 parts by weight of modified nano silica emulsion, 1-3 parts by weight of hexadecyltrimethoxysilane, and 30-50 parts by weight of polyurethane emulsion evenly, then coat both sides and dry.

[0009] The specific steps for impregnation with glue in S1 are as follows:

[0010] S1.1 Adjust the pH of 100 parts by weight of a 37% formaldehyde aqueous solution to 8.0-8.5, raise the temperature to 40-50℃, add 25-35 parts by weight of melamine and 25-55 parts by weight of urea, continue to raise the temperature to 90-95℃, keep the temperature for 40-60 min, adjust the pH to 5.0-5.5, and keep the temperature for 20-40 min.

[0011] S1.2 Add 15-35 parts by weight of urea, adjust the pH to 7.5-8.0, and continue the reaction at this temperature for 80-100 minutes.

[0012] S1.3. Cool to 45-55℃, add 5-10 parts by weight of diethylene glycol ether and 1-5 parts by weight of urea, stir for 60-90 minutes, then cool to room temperature, add 1-5 parts by weight of bentonite, 1-5 parts by weight of basalt fiber, 5-10 parts by weight of water, and 1-2 parts by weight of hexadecyltrimethoxysilane to obtain the impregnation adhesive.

[0013] S1.4. Immerse the base paper in the impregnation glue for 10-20 minutes and dry it at 50-70℃ to obtain melamine impregnated paper.

[0014] In S1.3, after cooling to room temperature, 1-5 parts by weight of basalt fibers with a diameter of 3-5 μm and 5-10 parts by weight of water are ground for 30-60 min. Then, 1-2 parts by weight of hexadecyltrimethoxysilane are added and stirred for 20-40 min. Next, 1-5 parts by weight of bentonite are added and stirred for 10-20 min to obtain the modified material. The modified material is then added to the system as a whole.

[0015] The basalt fibers have a diameter of 3-5 micrometers.

[0016] The preparation method of modified nano-silica emulsion in S2 is as follows: 40-50 parts by weight of isopropanol, pH value adjusted to 4-5 with acetic acid, and 10-20 parts by weight of water are stirred evenly. Then, while stirring, 10-20 parts by weight of aminopropyltriethoxysilane are added dropwise, and then 2-4 parts by weight of nano-silica are added and stirred evenly to obtain the emulsion.

[0017] The drying temperature for the glue impregnation in S1 is 130-140℃.

[0018] The drying temperature of the coating emulsion in S2 is 120-130℃. Beneficial effects

[0019] This invention provides a preparation process for improving the moisture-proof performance of impregnated paper. S1, Glue impregnation: The base paper is impregnated in short-fiber modified melamine glue for 30-60 minutes, then dried to obtain melamine impregnated paper; S2, Emulsion coating: 5-10 parts by weight of modified nano-silica emulsion, 1-3 parts by weight of hexadecyltrimethoxysilane, and 30-50 parts by weight of polyurethane emulsion are stirred evenly and then coated on both sides, followed by drying. This invention, by impregnating the base paper in short-fiber modified melamine glue during the glue impregnation step and then coating both sides with modified nano-silica emulsion and polyurethane emulsion during the emulsion coating step, combines physical and chemical moisture-proofing, creating an upper-layer moisture-proof system from the inside out, effectively improving the moisture-proof performance of the impregnated paper. Detailed Implementation

[0020] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Example 1

[0021] A preparation process for improving the moisture-proof properties of impregnated paper specifically includes the following steps:

[0022] S1. Glue impregnation: Immerse the base paper in modified melamine glue for 35 minutes, then dry to obtain melamine-impregnated paper;

[0023] S2. Coating emulsion: Mix 5 parts by weight of modified nano silica emulsion, 1 part by weight of hexadecyltrimethoxysilane, and 30 parts by weight of polyurethane emulsion evenly, then coat both sides and dry.

[0024] The specific steps for impregnation with glue in S1 are as follows:

[0025] S1.1 Add 100 parts by weight of a 37% formaldehyde aqueous solution and adjust the pH value to 8.0. Heat to 40°C, add 25 parts by weight of melamine and 25 parts by weight of urea, continue to heat to 90°C, keep the temperature for 40 min, adjust the pH value to 5.0, and keep the temperature for 20 min.

[0026] S1.2 Add 15 parts by weight of urea, adjust the pH to 7.5, and continue the reaction at this temperature for 80 minutes.

[0027] S1.3. Cool to 45°C, add 5 parts by weight of diethylene glycol ether and 1 part by weight of urea, stir for 60 minutes, cool to room temperature, add 1 part by weight of bentonite, 1 part by weight of basalt fiber, 5 parts by weight of water and 1 part by weight of hexadecyltrimethoxysilane to obtain impregnation adhesive.

[0028] S1.4. Immerse the base paper in the impregnation glue for 10 minutes and dry it at 50°C to obtain melamine impregnated paper.

[0029] In S1.3, after cooling to room temperature, 1 part by weight of basalt fiber with a diameter of 3 μm and 5 parts by weight of water are ground for 30 min. 1 part by weight of hexadecyltrimethoxysilane is added and stirred for 20 min. Then, 1 part by weight of bentonite is added and stirred for another 10 min to obtain the modified material. The modified material is then added to the system as a whole.

[0030] The basalt fibers have a diameter of 3 micrometers.

[0031] The preparation method of modified nano-silica emulsion in S2 is as follows: 40 parts by weight of isopropanol are adjusted to pH 4 with acetic acid and stirred evenly with 10 parts by weight of water. Then, 10 parts by weight of aminopropyltriethoxysilane are added dropwise while stirring, and then 2 parts by weight of nano-silica are added and stirred evenly to obtain the emulsion.

[0032] The drying temperature for the glue impregnation in S1 is 130°C.

[0033] The drying temperature of the coating emulsion in S2 is 120°C. Example 2

[0034] A preparation process for improving the moisture-proof properties of impregnated paper specifically includes the following steps:

[0035] S1. Glue impregnation: Immerse the base paper in modified melamine glue for 40 minutes, then dry to obtain melamine-impregnated paper;

[0036] S2. Coating emulsion: Mix 8 parts by weight of modified nano silica emulsion, 2 parts by weight of hexadecyltrimethoxysilane, and 40 parts by weight of polyurethane emulsion evenly, then coat both sides and dry.

[0037] The specific steps for impregnation with glue in S1 are as follows:

[0038] S1.1 Add 100 parts by weight of a 37% formaldehyde aqueous solution and adjust the pH value to 8.5. Heat to 45°C, add 30 parts by weight of melamine and 40 parts by weight of urea, continue to heat to 92°C, keep the temperature for 50 min, adjust the pH value to 5.5, and keep the temperature for 30 min.

[0039] S1.2 Add 25 parts by weight of urea, adjust the pH to 7.8, and continue the reaction at this temperature for 90 minutes.

[0040] S1.3. Cool to 50°C, add 8 parts by weight of diethylene glycol ether and 3 parts by weight of urea, stir for 70 minutes, then cool to room temperature, add 3 parts by weight of bentonite, 3 parts by weight of basalt fiber, 8 parts by weight of water and 1 part by weight of hexadecyltrimethoxysilane to obtain impregnation adhesive.

[0041] S1.4. Immerse the base paper in the impregnation glue for 15 minutes and dry it at 60°C to obtain melamine impregnated paper.

[0042] In S1.3, after cooling to room temperature, 3 parts by weight of basalt fiber and 8 parts by weight of water are ground for 50 minutes. 1 part by weight of hexadecyltrimethoxysilane is added and stirred for 30 minutes. Then, 3 parts by weight of bentonite are added and stirred for another 15 minutes to obtain the modified material. The modified material is then added to the system as a whole.

[0043] The basalt fibers have a diameter of 4 micrometers.

[0044] The preparation method of modified nano-silica emulsion in S2 is as follows: 45 parts by weight of isopropanol are adjusted to pH 5 with acetic acid and stirred evenly with 15 parts by weight of water. Then, while stirring, 15 parts by weight of aminopropyltriethoxysilane are added dropwise, and then 3 parts by weight of nano-silica are added and stirred evenly to obtain the emulsion.

[0045] The drying temperature for the glue impregnation in S1 is 135°C.

[0046] The drying temperature of the coating emulsion in S2 is 125°C. Example 3

[0047] A preparation process for improving the moisture-proof properties of impregnated paper specifically includes the following steps:

[0048] S1. Glue impregnation: Immerse the base paper in modified melamine glue for 60 minutes, then dry to obtain melamine-impregnated paper;

[0049] S2. Coating emulsion: Mix 10 parts by weight of modified nano silica emulsion, 3 parts by weight of hexadecyltrimethoxysilane, and 50 parts by weight of polyurethane emulsion evenly, then coat both sides and dry.

[0050] The specific steps for impregnation with glue in S1 are as follows:

[0051] S1.1 Add 100 parts by weight of a 37% formaldehyde aqueous solution and adjust the pH value to 8.5. Heat to 50°C, add 35 parts by weight of melamine and 55 parts by weight of urea, continue to heat to 95°C, keep the temperature for 60 min, adjust the pH value to 5.5, and keep the temperature for 40 min.

[0052] S1.2 Add 35 parts by weight of urea, adjust the pH to 8.0, and continue the reaction at this temperature for 100 minutes.

[0053] S1.3. Cool to 55°C, add 10 parts by weight of diethylene glycol ether and 5 parts by weight of urea, stir for 90 minutes, then cool to room temperature, add 5 parts by weight of bentonite, 5 parts by weight of basalt fiber, 10 parts by weight of water and 2 parts by weight of hexadecyltrimethoxysilane to obtain impregnation adhesive.

[0054] S1.4. Immerse the base paper in the impregnation glue for 20 minutes and dry it at 70°C to obtain melamine impregnated paper.

[0055] In S1.3, after cooling to room temperature, 5 parts by weight of basalt fiber with a diameter of 5 μm and 10 parts by weight of water are ground for 60 min. 2 parts by weight of hexadecyltrimethoxysilane are added and stirred for 40 min. Then, 5 parts by weight of bentonite are added and stirred for another 20 min to obtain the modified material. The modified material is then added to the system as a whole.

[0056] The basalt fibers have a diameter of 5 micrometers.

[0057] The preparation method of modified nano-silica emulsion in S2 is as follows: 50 parts by weight of isopropanol are adjusted to pH 5 with acetic acid and stirred evenly with 20 parts by weight of water. Then, while stirring, 20 parts by weight of aminopropyltriethoxysilane are added dropwise, and then 4 parts by weight of nano-silica are added and stirred evenly to obtain the emulsion.

[0058] The drying temperature for adhesive impregnation in S1 is 140℃, and the amount of adhesive applied is 75g / ㎡.

[0059] The drying temperature of the emulsion in S2 is 130℃, and the emulsion coating amount is 10g / ㎡.

[0060] In Examples 1-3 of this invention, the alkaline modifier in the glue impregnation is a sodium hydroxide solution with a mass fraction of 15%, and the acid modifier is a formic acid solution with a mass fraction of 3%.

[0061] The preparation method of the polyurethane emulsion in Examples 1-3 of this invention is as follows:

[0062] (1) 200 parts by weight of polyether polyol (PTMG 2000), 40 parts by weight of polybutylene adipate (PBA) and 5 parts by weight of 1,4-butanediol were mixed evenly, and then 100 parts by weight of TDI-80 were added. The prepolymerization reaction was carried out for 3 hours at 75°C with 0.1 parts by weight of bismuth isooctanoate.

[0063] (2) Cool the prepolymer to 45°C, add 170 parts by weight of butyl acrylate monomer to the prepolymer, stir for 60 min, add 15 parts by weight of triethylamine, stir for 15 min to react and form a salt; then cool the reactor to 20°C, add 460 parts by weight of water and stir to emulsify, add 5 parts by weight of an aqueous solution of ethylenediamine (mass fraction of 20%), and continue stirring to react for 30 min.

[0064] (3) Heat to 75°C, add 0.05 parts by weight of an aqueous solution of ammonium persulfate (mass fraction of 0.25%) as an initiator at a uniform rate over 3 hours, then heat to 80°C and keep warm for 2 hours, then cool to room temperature to obtain a polyurethane emulsion.

[0065] Comparative Example 1

[0066] The difference between this comparative example and Example 2 is that this comparative example does not use modified adhesive, but instead uses the adhesive impregnation steps described in S1.

[0067] S1.1 Add 100 parts by weight of a 37% formaldehyde aqueous solution and adjust the pH value to 8.5. Heat to 45°C, add 30 parts by weight of melamine and 40 parts by weight of urea, continue to heat to 92°C, keep the temperature for 50 min, adjust the pH value to 5.5, and keep the temperature for 30 min.

[0068] S1.2 Add 25 parts by weight of urea, adjust the pH to 7.8, and continue the reaction at this temperature for 90 minutes.

[0069] S1.3. Cool to 50°C, add 8 parts by weight of diethylene glycol ether and 3 parts by weight of urea, stir for 70 minutes, then cool to room temperature to obtain the impregnation adhesive.

[0070] S1.4. Immerse the base paper in the impregnation glue for 15 minutes and dry it at 60°C to obtain melamine impregnated paper.

[0071] Comparative Example 2

[0072] The difference between this comparative example and Example 2 is that this comparative example does not use the step of coating emulsion.

[0073] Experimental data

[0074] The embodiment of this invention uses a water absorption tester, model ST-5684. The specific formula for the water absorption of paper is: C=(G2-G1)×100, where C is the water absorption value; G2 is the mass of the paper sample after water absorption; and G1 is the mass of the paper sample before water absorption.

[0075] The water absorption values ​​of the three samples were calculated by using a water absorption tester to test Examples 1-3 and Comparative Examples 1-2 respectively.

[0076]

[0077] By comparison, the water absorption values ​​of the impregnated paper obtained by Comparative Example 1 without modified glue and Comparative Example 2 without coating emulsion are far inferior to those of Examples 1-3. Comparative Examples 1 and 2 have poor moisture-proof performance, while the moisture-proof performance of the embodiments of the present invention is good.

[0078] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0079] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A preparation process for improving the moisture-proof performance of impregnated paper, characterized in that, Specifically, the following steps are included: S1. Glue impregnation: Immerse the base paper in short fiber modified melamine glue for 30-60 minutes, then dry to obtain melamine impregnated paper; S2. Coating Emulsion: Mix 5-10 parts by weight of modified nano-silica emulsion, 1-3 parts by weight of hexadecyltrimethoxysilane, and 30-50 parts by weight of polyurethane emulsion evenly, then coat both sides and dry. The specific steps of the glue impregnation in S1 are as follows: S1.1 Adjust the pH of 100 parts by weight of a 37% formaldehyde aqueous solution to 8.0-8.5, raise the temperature to 40-50℃, add 25-35 parts by weight of melamine and 25-55 parts by weight of urea, continue to raise the temperature to 90-95℃, keep the temperature for 40-60 min, adjust the pH to 5.0-5.5, and keep the temperature for 20-40 min. S1.2 Add 15-35 parts by weight of urea, adjust the pH to 7.5-8.0, and continue the reaction at this temperature for 80-100 minutes. S1.

3. Cool to 45-55℃, add 5-10 parts by weight of diethylene glycol ether and 1-5 parts by weight of urea, stir for 60-90 minutes, then cool to room temperature, add 1-5 parts by weight of bentonite, 1-5 parts by weight of basalt fiber, 5-10 parts by weight of water, and 1-2 parts by weight of hexadecyltrimethoxysilane to obtain impregnation adhesive. S1.

4. Immerse the base paper in the impregnation glue solution for 10-20 minutes, then dry at 50-70℃ to obtain melamine-impregnated paper. In S1.3, after cooling to room temperature, 1-5 parts by weight of basalt fiber and 5-10 parts by weight of water are ground for 30-60 minutes. Then, 1-2 parts by weight of hexadecyltrimethoxysilane are added and stirred for 20-40 minutes. Next, 1-5 parts by weight of bentonite are added and stirred for another 10-20 minutes to obtain the modified material. This modified material is then added to the system as a whole. The preparation method of the modified nano-silica emulsion in S2 is as follows: 40-50 parts by weight of isopropanol are adjusted to pH 4-5 with acetic acid and stirred evenly with 10-20 parts by weight of water. Then, while stirring, 10-20 parts by weight of aminopropyltriethoxysilane are added dropwise, and then 2-4 parts by weight of nano-silica are added and stirred evenly to obtain the emulsion.

2. The preparation process for improving the moisture-proof performance of impregnated paper according to claim 1, characterized in that: The basalt fibers have a diameter of 3-5 micrometers.

3. The preparation process for improving the moisture-proof performance of impregnated paper according to claim 1, characterized in that: The drying temperature for the glue impregnation in S1 is 130-140℃.

4. The preparation process for improving the moisture-proof performance of impregnated paper according to claim 1, characterized in that: The drying temperature of the coating emulsion in S2 is 120-130℃.

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