A hot-pressing process for melamine impregnated paper decorative panel of glass-magnesium composite board

Abstract

The application discloses a kind of melamine impregnated paper decorative panel hot-pressing process for glass magnesium composite board, belongs to decorative panel technical field, including the following steps: decorative paper is dipped into melamine resin adhesive and impregnated, then dried and used, the surface of glass magnesium plate is polished and pretreated, then melamine impregnated paper is laid on the surface of glass magnesium plate after polishing pretreatment, blank plate is obtained, temperature is set to 60±5 ℃, pressure is 9-10MPa, hot-pressing is carried out, hot-pressing time is 20-25 seconds, preheating is carried out, then heated to 110-120 ℃, continue hot-pressing for 2-3min, naturally cooled to 60 ℃±10 ℃, finished product is obtained. By controlling hot-pressing condition and using melamine resin adhesive, the adhesion between materials in hot-pressing process is improved, and the adhesion effect is improved, the covering curl of decorative paper is reduced, and the curing efficiency is improved.

Description

Technical Field

[0001] This invention belongs to the field of decorative panel technology, specifically relating to a hot-pressing process for melamine-impregnated paper decorative panels used in glass-magnesium composite boards. Background Technology

[0002] Magnesium oxide composite board is a new type of high-tech composite board. This material is composed of two layers of high-strength inorganic materials and one layer of insulation material. It features lightweight, high strength, non-combustibility, sound insulation, and suitability for humid environments. It is used in residential projects for interior partition walls, ceilings, doors, and chimneys, as well as in office buildings, mobile homes, kitchens, bathrooms, and laundry room partitions.

[0003] Because magnesium oxide boards are not very decorative, their surface needs to be further processed by laminating melamine-impregnated paper for decoration. The requirements for the adhesives used vary depending on the application environment. In addition, the hot-pressing process has high requirements, as it directly affects the bonding effect. After the resin impregnated with melamine decorative paper is cured into a film by hot pressing, it is still greatly affected by the ambient temperature and humidity. It is prone to cracking after moisture loss. The inconsistent expansion and contraction of the material layer and the decorative layer due to changes in ambient temperature and humidity can also cause warping and deformation problems. Summary of the Invention

[0004] The purpose of this invention is to provide a hot-pressing process for melamine-impregnated paper decorative panels for magnesium oxide composite boards, in order to solve the problem of warping and deformation caused by inconsistent expansion and contraction of the material layer and decorative layer due to environmental changes during secondary processing of magnesium oxide composite boards.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] A hot-pressing process for melamine-impregnated paper decorative panels on magnesium oxide composite boards includes the following steps:

[0007] The printed decorative paper is immersed in melamine resin adhesive, then dried and set aside. The surface of the magnesium oxide board is pre-treated by sanding. Then, the melamine-impregnated paper is laid flat on the pre-treated surface of the magnesium oxide board to obtain a blank. The temperature is set to 60±5℃ and the pressure to 9-10MPa for hot pressing for 20-25 seconds. This is a preheated pressing. Then, the temperature is raised to 110-120℃ and hot pressing is continued for 2-3 minutes. After natural cooling to 60℃±10℃, the finished product is obtained.

[0008] The pre-treatment for grinding includes the following steps:

[0009] Grind the magnesium oxide board in sequence with 80#, 150#, and 180# silicon carbide sanders until there are no obvious pits on the surface of the magnesium oxide board.

[0010] Furthermore, the weight ratio of the decorative paper before and after impregnation is 1:1.5-1.9.

[0011] Furthermore, the melamine resin adhesive is prepared by the following steps:

[0012] Mix glucose modifier and deionized water, adjust the pH to 10, set the temperature to 95℃, add paraformaldehyde, sodium tetraborate and melamine in sequence, stir and react for 40 min, then add distilled water to dilute 2-3 times, cool to room temperature to obtain melamine resin adhesive.

[0013] Furthermore, the ratio of glucose modifier, deionized water, paraformaldehyde, and melamine is 0.4g:50mL:18g:10g; the mass ratio of melamine to sodium tetraborate is 1:0.03.

[0014] Furthermore, the glucose modifier is prepared by the following steps:

[0015] Tridecafluorooctyl alcohol and an aqueous sodium hydroxide solution were mixed, and then tetrabutylammonium bromide and n-hexane were added. Epichlorohydrin was added while stirring, and the reaction was carried out at 40°C for 6 hours. After the reaction was completed, the mixture was washed with water and the solvent was removed by vacuum distillation to obtain intermediate product a. Intermediate product a and the amino monomer were added to methanol and the reaction was carried out at 30°C for 10 hours. After the reaction was completed, the solvent was removed by vacuum distillation to obtain intermediate product b. The mass fraction of the aqueous sodium hydroxide solution was 50%. The molar ratio of tridecafluorooctyl alcohol, epichlorohydrin, aqueous sodium hydroxide solution, tetrabutylammonium bromide, and n-hexane was 0.03 mol: 0.04 mol: 100 mL: 0.015 mol: 150 mL. The molar ratio of intermediate product a, amino monomer, and methanol was 4 g: 0.1 mol. l: 60mL; The reaction process is as follows: the hydroxyl group in tridecafluorooctyl alcohol reacts with epichlorohydrin under the catalysis of tetrabutylammonium bromide to generate intermediate product a. Intermediate product a contains epoxy group. The epoxy group reacts with amino monomer to form imino group. The imino group reacts with gluconolactone to generate glucose modifier containing amide structure. Glucose modifier is a nonionic surfactant.

[0016] Intermediate product b and gluconolactone were added to ethanol and stirred at 20°C for 20 h. The mixture was then refluxed for 4 h. After the reaction was complete, the solvent was removed by vacuum distillation to obtain the glucose modifier. The ratio of intermediate product b, gluconolactone, and ethanol was 4 g: 0.15 mol: 50 mL.

[0017] Furthermore, the amino monomer is one of n-butylamine and n-propylamine.

[0018] The beneficial effects of this invention are:

[0019] In the hot-pressing process of this invention, hot pressing is carried out in two stages. In the first hot pressing process, the melamine resin adhesive is preheated, and low-temperature hot pressing is used to remove air bubbles generated in the adhesive, preventing poor adhesion caused by the presence of air bubbles. By controlling the hot pressing process, the adhesion between materials is improved, the curling of decorative paper is reduced, and the bonding effect is improved. In the second hot pressing process, the temperature is increased to improve the curing efficiency, reduce the release of free formaldehyde and the absorption of aldehydes by the board.

[0020] This invention incorporates a glucose modifier during the preparation of melamine resin adhesive. The hydroxyl groups in the glucose modifier react with melamine-formaldehyde resin to generate condensation products, reducing cross-linking between resin molecules and achieving toughening. This improves the brittleness of the melamine-formaldehyde resin adhesive after curing and enhances its storage stability. To further improve the impact of environmental humidity on the material and decorative layers of the glass-magnesium composite board during secondary processing, tridecafluorooctyl alcohol is added to the prepared glucose modifier, introducing a fluorine modifier. The CF bonds in the organic fluorine compound impart excellent chemical stability to the adhesive, improving its hydrophobicity after curing, reducing expansion and contraction caused by changes in environmental humidity, enhancing the adhesion between the material and decorative layers, and preventing warping and deformation. Detailed Implementation

[0021] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. 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 of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0022] Example 1

[0023] This embodiment provides a melamine resin adhesive, which is prepared through the following steps:

[0024] Tridecafluorooctyl alcohol and sodium hydroxide aqueous solution were mixed, then tetrabutylammonium bromide and n-hexane were added, and epichlorohydrin was added while stirring. The reaction was carried out at 40°C for 6 hours. After the reaction was completed, the mixture was washed with water and the solvent was removed by vacuum distillation to obtain intermediate product a. Intermediate product a and n-propylamine were added to methanol and the reaction was carried out at 30°C for 10 hours. After the reaction was completed, the solvent was removed by vacuum distillation to obtain intermediate product b. The mass fraction of sodium hydroxide aqueous solution was 50%. The molar ratio of tridecafluorooctyl alcohol, epichlorohydrin, sodium hydroxide aqueous solution, tetrabutylammonium bromide and n-hexane was 0.03 mol: 0.04 mol: 100 mL: 0.015 mol: 150 mL. The molar ratio of intermediate product a, amino monomer and methanol was 4 g: 0.1 mol: 60 mL.

[0025] Intermediate product b and gluconolactone were added to ethanol and stirred at 20°C for 20 h. The mixture was then refluxed for 4 h. After the reaction was complete, the solvent was removed by vacuum distillation to obtain the glucose modifier. The ratio of intermediate product b, gluconolactone, and ethanol was 4 g: 0.15 mol: 50 mL.

[0026] Glucose modifier and deionized water were mixed, the pH was adjusted to 10, the temperature was set to 95℃, paraformaldehyde, sodium tetraborate and melamine were added in sequence, the mixture was stirred for 40 min, then diluted twice with distilled water and cooled to room temperature to obtain melamine resin adhesive; the ratio of glucose modifier, deionized water, paraformaldehyde and melamine was 0.4g:50mL:18g:10g; the mass ratio of melamine and sodium tetraborate was 1:0.03.

[0027] Example 2

[0028] This embodiment provides a melamine resin adhesive, which is prepared through the following steps:

[0029] Tridecafluorooctyl alcohol and sodium hydroxide aqueous solution were mixed, and then tetrabutylammonium bromide and n-hexane were added. Epichlorohydrin was added while stirring, and the reaction was carried out at 40°C for 6 hours. After the reaction was completed, the mixture was washed with water and the solvent was removed by vacuum distillation to obtain intermediate product a. Intermediate product a and n-butylamine were added to methanol and the reaction was carried out at 30°C for 10 hours. After the reaction was completed, the solvent was removed by vacuum distillation to obtain intermediate product b. The mass fraction of sodium hydroxide aqueous solution was 50%. The molar ratio of tridecafluorooctyl alcohol, epichlorohydrin, sodium hydroxide aqueous solution, tetrabutylammonium bromide and n-hexane was 0.03 mol: 0.04 mol: 100 mL: 0.015 mol: 150 mL. The molar ratio of intermediate product a, amino monomer and methanol was 4 g: 0.1 mol: 60 mL.

[0030] Intermediate product b and gluconolactone were added to ethanol and stirred at 20°C for 20 h. The mixture was then refluxed for 4 h. After the reaction was complete, the solvent was removed by vacuum distillation to obtain the glucose modifier. The ratio of intermediate product b, gluconolactone, and ethanol was 4 g: 0.15 mol: 50 mL.

[0031] Glucose modifier and deionized water were mixed, the pH was adjusted to 10, the temperature was set to 95℃, paraformaldehyde, sodium tetraborate and melamine were added in sequence, the mixture was stirred for 40 min, then diluted 3 times with distilled water and cooled to room temperature to obtain melamine resin adhesive; the ratio of glucose modifier, deionized water, paraformaldehyde and melamine was 0.4g:50mL:18g:10g; the mass ratio of melamine and sodium tetraborate was 1:0.03.

[0032] Comparative Example 1

[0033] This comparative example provides a melamine resin adhesive a, which is prepared by the following steps:

[0034] Glucose and deionized water were mixed, the pH was adjusted to 10, and the temperature was set to 95℃. Paraformaldehyde, sodium tetraborate, and melamine were added sequentially, and the mixture was stirred for 40 min. Then, distilled water was added to dilute the mixture by 2 times, and the mixture was cooled to room temperature to obtain melamine resin adhesive. The ratio of glucose to deionized water and paraformaldehyde to melamine was 0.4 g: 50 mL: 18 g: 10 g; the mass ratio of melamine to sodium tetraborate was 1: 0.03.

[0035] Example 3

[0036] A hot-pressing process for melamine-impregnated paper decorative panels on magnesium oxide composite boards includes the following steps:

[0037] The magnesium oxide board was sanded sequentially with 80#, 150#, and 180# silicon carbide abrasive belts until there were no obvious pits on the surface. Decorative paper with printed patterns was then immersed in the melamine resin adhesive prepared in Example 1, with a weight ratio of 1:1.5 before and after immersion. After drying, the surface of the magnesium oxide board was pre-treated by sanding. Then, the melamine-impregnated paper was laid flat on the surface of the pre-treated magnesium oxide board to obtain a blank. The temperature was set at 60±5℃ and the pressure at 9MPa for hot pressing for 20 seconds. This was followed by pre-heat pressing, then the temperature was raised to 110℃ and hot pressing was continued for 2 minutes. After natural cooling to 60℃±10℃, the finished product was obtained.

[0038] Example 4

[0039] A hot-pressing process for melamine-impregnated paper decorative panels on magnesium oxide composite boards includes the following steps:

[0040] The magnesium oxide board was sanded sequentially with 80#, 150#, and 180# silicon carbide abrasive belts until there were no obvious pits on the surface. Decorative paper with printed patterns was then immersed in the melamine resin adhesive prepared in Example 2, with a weight ratio of 1:1.9 before and after immersion. After drying, the surface of the magnesium oxide board was pre-treated by sanding. Then, the melamine-impregnated paper was laid flat on the surface of the pre-treated magnesium oxide board to obtain a blank. The temperature was set at 60±5℃ and the pressure at 10MPa for hot pressing for 20 seconds. This was followed by pre-heat pressing, then the temperature was raised to 120℃ and hot pressing was continued for 3 minutes. After natural cooling to 60℃±10℃, the finished product was obtained.

[0041] Example 5

[0042] A hot-pressing process for melamine-impregnated paper decorative panels on magnesium oxide composite boards includes the following steps:

[0043] The magnesium oxide board was sanded sequentially with 80#, 150#, and 180# silicon carbide abrasive belts until there were no obvious pits on the surface. Decorative paper with printed patterns was then immersed in the melamine resin adhesive prepared in Example 2, with a weight ratio of 1:1.9 before and after immersion. After drying, the surface of the magnesium oxide board was pre-treated by sanding. Then, the melamine-impregnated paper was laid flat on the surface of the pre-treated magnesium oxide board to obtain a blank. The temperature was set at 60±5℃ and the pressure at 10MPa for hot pressing for 25 seconds. This was followed by pre-heat pressing, then the temperature was raised to 120℃ and hot pressing was continued for 3 minutes. After natural cooling to 60℃±10℃, the finished product was obtained.

[0044] Comparative Example 2

[0045] Compared with Example 5, the melamine resin adhesive in this comparative example is replaced with melamine resin adhesive a prepared in Comparative Example 1, while the other raw materials and preparation process remain the same as in Example 5.

[0046] Comparative Example 3

[0047] Compared with Comparative Example 2, the hot pressing process conditions in this comparative example were changed to: temperature of 120℃, pressure of 10MPa, hot pressing for 3 min, and then naturally cooled to 60℃±10℃ to obtain the finished product.

[0048] The samples prepared in Examples 3-5 and Comparative Examples 2-3 were tested according to standards GB / T17657-2013 and GB / T41547-2022. The test results are shown in Table 1.

[0049] Table 1

[0050]

[0051] As can be seen from Table 1, the decorative panel prepared by the hot pressing process of melamine impregnated paper decorative panel for glass magnesium composite board according to the present invention has good stability, good adhesion between the material layer and the decorative layer, and is not prone to warping or deformation under changes in ambient temperature and humidity.

[0052] 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.

[0053] 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 hot-pressing process for melamine-impregnated paper decorative panels used in glass-magnesium composite boards, characterized in that, The process includes the following steps: immersing decorative paper in melamine resin adhesive, drying it, and then pre-treating the surface of the magnesium oxide board by sanding. Then, laying the melamine-impregnated paper flat on the pre-treated surface of the magnesium oxide board to obtain a blank. The blank is then hot-pressed at a temperature of 60±5℃ and a pressure of 9-10MPa for 20-25 seconds. After pre-pressing, the temperature is raised to 110-120℃ and hot-pressed for another 2-3 minutes. Finally, the blank is allowed to cool naturally to 60℃±10℃ to obtain the finished product. The melamine resin adhesive is prepared by the following steps: Tridecafluorooctol and sodium hydroxide aqueous solution were mixed, then tetrabutylammonium bromide and n-hexane were added, and epichlorohydrin was added while stirring. The reaction was carried out at 40℃ for 6 hours. After the reaction was completed, the product was washed with water and the solvent was removed by vacuum distillation to obtain intermediate product a. Intermediate product a and amino monomer were added to methanol and the reaction was carried out at 30℃ for 10 hours. After the reaction was completed, the solvent was removed by vacuum distillation to obtain intermediate product b. The mass fraction of sodium hydroxide aqueous solution was 50%, and the molar ratio of tridecafluorooctol, epichlorohydrin, sodium hydroxide aqueous solution, tetrabutylammonium bromide and n-hexane was 0.03mol:0.04mol:100mL:0.015mol:150mL. The ratio of intermediate product a, amino monomer, and methanol was 4 g: 0.1 mol: 60 mL. Intermediate product b and gluconolactone were added to ethanol and stirred at 20°C for 20 h. Then the mixture was refluxed for 4 h. After the reaction was completed, the solvent was removed by vacuum distillation to obtain the glucose modifier. The ratio of intermediate product b, gluconolactone and ethanol was 4 g: 0.15 mol: 50 mL. Mix glucose modifier and deionized water, adjust the pH to 10, set the temperature to 95℃, add paraformaldehyde, sodium tetraborate and melamine in sequence, stir and react for 40 minutes, then add distilled water to dilute 2-3 times, cool to room temperature to obtain melamine resin adhesive.

2. The hot-pressing process for melamine-impregnated paper decorative panels used in glass-magnesium composite boards according to claim 1, characterized in that, The weight ratio of decorative paper before and after impregnation is 1:1.5-1.

9.

3. The hot-pressing process for melamine-impregnated paper decorative panels used in glass-magnesium composite boards according to claim 1, characterized in that, The ratio of glucose modifier, deionized water, paraformaldehyde and melamine is 0.4g:50mL:18g:10g; the mass ratio of melamine and sodium tetraborate is 1:0.

03.

4. The hot-pressing process for melamine-impregnated paper decorative panels used in glass-magnesium composite boards according to claim 1, characterized in that, The amino monomer is one of n-butylamine or n-propylamine.

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