Modified high-water-miscibility phenolic resin emulsion as well as preparation method and application thereof

Abstract

The invention provides a modified high-water-miscibility phenolic resin emulsion as well as a preparation method and application thereof, and belongs to the technical field of phenolic resin. The modified high-water-miscibility phenolic resin emulsion is prepared from the following raw materials in parts by weight: 100 parts of a formaldehyde aqueous solution, 50 to 80 parts of phenol, 2 to 6 parts of a catalyst, 14 to 20 parts of a modifier A, 2 to 10 parts of a modifier B and 2 to 6 parts of an emulsifier, wherein the modifier A is melamine and / or dicyandiamide, and the modifier B is urea and / or ethylene urea. The modified high-water-miscibility phenolic resin emulsion disclosed by the invention has relatively high molecular weight, the content of free formaldehyde and free phenol in the phenolic resin emulsion is low, and the modified high-water-miscibility phenolic resin emulsion is green and environment-friendly; through specific synthesis and emulsification processes, the prepared phenolic aldehyde emulsion has the characteristic of infinite miscibility with water, has excellent miscibility with auxiliary materials such as silane, polyhydric alcohols, color paste and the like, and is high in process adaptability.

Description

Technical Field

[0001] The invention belongs to the technical field of phenolic resins, and in particular relates to a modified high water-miscible phenolic resin emulsion and a preparation method and application thereof. Background Art

[0002] Phenolic resin is an important synthetic resin with excellent properties such as high mechanical strength, good wear resistance, dimensional stability, weather resistance, corrosion resistance, flame retardancy, insulation and heat insulation, low smoke and low toxicity. It is widely used in wood and bamboo reconstituted materials (i.e. reconstituted bamboo, reconstituted wood), artificial boards, wet curtain paper, impregnated coated paper, coated abrasives, bonded abrasives, thermal insulation materials, friction materials, composite materials, ablation-resistant materials and other fields.

[0003] Traditional phenolic resins are mainly made of phenol, formaldehyde and catalysts. Under certain temperature conditions, the hydrogen atoms at the ortho-para positions of the phenolic hydroxyl groups in phenol react with the aldehyde groups (-CHO) in formaldehyde to form a series of intermediate condensates. These products further react to obtain polycondensates, and even cross-link to form a three-dimensional network structure. In order to meet the practicality of the resin, the reaction must be controlled to a certain extent, resulting in a large amount of free phenol and free formaldehyde remaining in the final product, which pose a potential threat to human health. If the free components contained in the resin are to be reduced, the degree of polycondensation needs to be deepened and the molecular weight needs to be increased, which will cause the water miscibility of the resin to decrease, and even phase separation will occur, which will seriously affect the application performance of the resin. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a modified high water-miscible phenolic resin emulsion and a preparation method thereof.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] One of the technical solutions of the present invention:

[0007] A modified highly water-miscible phenolic resin emulsion, comprising, by weight, 100 parts of formaldehyde aqueous solution, 50-80 parts of phenol, 2-6 parts of catalyst, 14-20 parts of modifier A, 2-10 parts of modifier B and 2-6 parts of emulsifier;

[0008] The modifier A is melamine and / or dicyandiamide;

[0009] The modifier B is urea and / or ethylene urea.

[0010] Furthermore, the mass concentration of the formaldehyde aqueous solution is 50%.

[0011] Furthermore, the catalyst includes one or more of sodium hydroxide, potassium hydroxide, lithium hydroxide, calcium hydroxide, barium hydroxide, calcium oxide, ammonia water, triethylamine, dipropylenediamine and dimethylethanolamine.

[0012] Furthermore, the emulsifier is one or more of polyoxyethylene ethers, polyol monofatty acid esters and modified cellulose nonionic surfactants.

[0013] Further, the polyoxyethylene ether nonionic surfactant includes one or more of fatty alcohol polyoxyethylene ethers, alkylphenol polyoxyethylene ethers and polyol polyoxyethylene ether fatty acid esters, and exemplarily, it may be ceteareth-10, nonylphenol polyether-10 or polysorbate-20;

[0014] The polyol mono-fatty acid ester nonionic surfactant includes one or more of glycerol fatty acid ester, sorbitan ester and sucrose fatty acid ester, and exemplarily, glycerol stearate or sorbitan laurate;

[0015] The modified cellulose nonionic surfactant is one or more of hydroxyethyl cellulose aqueous solution, hydroxypropyl cellulose aqueous solution and methyl cellulose aqueous solution, and illustratively, it can be 1-5wt% hydroxyethyl cellulose aqueous solution, 1-5wt% hydroxypropyl cellulose aqueous solution or 1-5wt% methyl cellulose aqueous solution.

[0016] The modified highly water-miscible phenolic resin emulsion of the present invention has a non-volatile matter content of 25-55wt%, preferably 35-45wt%; a viscosity of 50-500mPa·s, preferably 100-300mPa·s; a free formaldehyde content of ≤0.3%; a free phenol content of ≤2%, preferably ≤1%; a pH of 6.5-7.8, a weight-average molecular weight of 1000-6000, and can be miscible with water in any proportion.

[0017] The second technical solution of the present invention:

[0018] A method for preparing the modified highly water-miscible phenolic resin emulsion comprises the following steps:

[0019] Weigh the raw materials by weight, mix the formaldehyde aqueous solution with the modifier A, adjust the pH to alkaline, carry out the first heat preservation reaction, add phenol and catalyst after the reaction, adjust the pH of the mixture to near neutral after the polycondensation reaction, add emulsifier and water for emulsification reaction, add modifier B after the reaction, carry out the second heat preservation reaction, and obtain the modified highly water-miscible phenolic resin emulsion.

[0020] Modifier A (melamine and / or dicyandiamide) of the present invention can react with formaldehyde to generate polymethylol compounds, increase the crosslinking density of resin, and improve its heat resistance and mechanical strength. Carrying out polycondensation after adding phenol and catalyst is the key step of phenolic resin formation, in this process, phenolic mixture further condenses to form phenolic resin, along with the carrying out of reaction degree, free formaldehyde and free phenol in resin continue to decline, and water miscibility also can decline simultaneously, when reaction reaches a certain degree, regulate pH, reduce the chromaticity of resin, add emulsifier and water simultaneously, carry out emulsification reaction, improve the water miscibility of resin. Second heat preservation reaction carried out after adding modifier B (urea and / or ethylene urea), urea and / or ethylene urea can further react with methylol and free formaldehyde in resin, form urea-formaldehyde structure, help to reduce the content of free formaldehyde.

[0021] Furthermore, the temperature of the first insulation reaction is 80-90° C., and the insulation time is 30-60 minutes.

[0022] Furthermore, the temperature of the second insulation reaction is 50-70° C., and the insulation time is 1-2 hours.

[0023] Furthermore, the temperature of the polycondensation reaction is 70-90° C., and the viscosity of the mixture after the polycondensation reaction is 200-500 mPa·s.

[0024] Further, an emulsifier and water are added to carry out emulsification reaction at 55-75° C. for 1-3 hours.

[0025] Further, the formaldehyde aqueous solution is mixed with the modifier A, and the pH is adjusted to 9.0-9.5.

[0026] Furthermore, after the polycondensation reaction, the pH of the mixture is adjusted to 6.5-7.5.

[0027] Furthermore, the formaldehyde aqueous solution is mixed with the modifier A, and the pH is adjusted with sodium hydroxide and / or potassium hydroxide.

[0028] Furthermore, after the polycondensation reaction, the pH of the mixture is adjusted with an acid, wherein the acid comprises one or more of p-toluenesulfonic acid, sulfuric acid, boric acid, phosphoric acid, acetic acid and formic acid.

[0029] Exemplarily, a method for preparing a modified highly water-miscible phenolic resin emulsion comprises the following steps:

[0030] Weigh the raw materials by weight, mix a formaldehyde aqueous solution with a mass concentration of 50% with a modifier A, adjust the pH to 9.0-9.5, and heat-keep the reaction at 80-90°C for 30-60 minutes, add phenol and a catalyst after the reaction, and perform a condensation reaction at 70-90°C until the viscosity is 200-500mPa·s to obtain a mixture, then adjust the pH of the mixture to 6.5-7.5, add an emulsifier and water, and perform an emulsification reaction at 55-75°C for 1-3 hours, and add a modifier B after the reaction, and perform a heat-keep reaction at 50-70°C for 1-2 hours to obtain a modified highly water-miscible phenolic resin emulsion.

[0031] The third technical solution of the present invention:

[0032] The modified high water-miscible phenolic resin emulsion is used in the fields of paper products, artificial boards, abrasives and tools, and composite materials.

[0033] Furthermore, the paper products field specifically includes air filter paper, wet curtain paper, impregnated coated paper, the artificial board field specifically includes plywood, particle board, bamboo composite materials, wood splicing materials, and the abrasive tools field specifically includes scouring pads and coated abrasives.

[0034] Compared with the prior art, the present invention has the following advantages and technical effects:

[0035] (1) The modified highly water-miscible phenolic resin emulsion of the present invention has good water miscibility, can be infinitely miscible with water, has strong process adaptability, and the container is easy to clean after use; the present invention greatly improves the miscibility of the phenolic resin emulsion with auxiliary materials such as silane, polyol, and color paste through a specific synthesis and emulsification process, greatly broadening the application range of the phenolic resin. In addition, the phenolic resin emulsion does not add any organic solvent, has low free formaldehyde and free phenol content, and is green and environmentally friendly.

[0036] (2) The modified highly water-miscible phenolic resin emulsion of the present invention uses phenolic resin as the main molecular chain, and by adjusting the phenolic resin ratio and adding a synergistic modifier, it has a relatively high molecular weight (1000-6000) while having low free formaldehyde and free phenol contents, and is green and environmentally friendly; in addition, the modified highly water-miscible phenolic resin emulsion of the present invention has a neutral pH, a light emulsion color, and a good emulsification effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0038] Figure 1 This is a physical picture of the modified highly water-miscible phenolic resin emulsion prepared in Example 1;

[0039] Figure 2 This is a picture of the modified high water-miscible phenolic resin emulsion prepared in Example 1 after being diluted with 10 times water;

[0040] Figure 3 This is a picture of the modified phenolic resin prepared in Comparative Example 1 after being diluted 10 times with water;

[0041] Figure 4 The microscopic imaging pictures of the modified highly water-miscible phenolic resin emulsion (a) prepared in Example 1 and the modified phenolic resin (b) prepared in Comparative Example 1 after mixing with auxiliary materials;

[0042] Figure 5 This is a physical picture of the wet curtain paper prepared in Application Example 1;

[0043] Figure 6 This is a physical picture of the plywood prepared in Application Example 2;

[0044] Figure 7 This is a physical picture of the impregnated coated paper prepared in Application Example 3. DETAILED DESCRIPTION

[0045] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0046] It should be understood that the terms described in the present invention are only for describing special embodiments and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0047] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0048] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present invention description and examples are exemplary only.

[0049] The terms "include", "including", "having", "containing", etc. used herein are open-ended terms, which mean including but not limited to. The embodiment of the present invention provides a modified highly water-miscible phenolic resin emulsion, wherein the raw materials, by weight, include: 100 parts of formaldehyde aqueous solution, 50-80 parts of phenol, 2-6 parts of catalyst, 14-20 parts of modifier A, 2-10 parts of modifier B and 2-6 parts of emulsifier;

[0050] In a preferred embodiment of the present invention, the modifier A is melamine and / or dicyandiamide.

[0051] In a preferred embodiment of the present invention, the modifier B is urea and / or ethylene urea.

[0052] In a preferred embodiment of the present invention, the mass concentration of the formaldehyde aqueous solution is 50%.

[0053] In a preferred embodiment of the present invention, the catalyst includes one or more of sodium hydroxide, potassium hydroxide, lithium hydroxide, calcium hydroxide, barium hydroxide, calcium oxide, ammonia water, triethylamine, dipropylenediamine and dimethylethanolamine. Exemplarily, the catalyst used is sodium hydroxide, potassium hydroxide or triethylamine.

[0054] In a preferred embodiment of the present invention, the emulsifier is one or more of polyoxyethylene ethers, polyol mono-fatty acid esters and modified cellulose non-ionic surfactants. Further, the polyoxyethylene ether non-ionic surfactant includes one or more of fatty alcohol polyoxyethylene ethers, alkylphenol polyoxyethylene ethers and polyol polyoxyethylene ether fatty acid esters, and exemplarily, it can be ceteareth-10, nonylphenol polyether-10 or polysorbate-20;

[0055] The polyol mono-fatty acid ester nonionic surfactant includes one or more of glycerol fatty acid ester, sorbitan ester and sucrose fatty acid ester, and exemplarily, glycerol stearate or sorbitan laurate;

[0056] The modified cellulose nonionic surfactant is one or more of hydroxyethyl cellulose aqueous solution, hydroxypropyl cellulose aqueous solution and methyl cellulose aqueous solution, and illustratively, it can be 1-5wt% hydroxyethyl cellulose aqueous solution, 1-5wt% hydroxypropyl cellulose aqueous solution or 1-5wt% methyl cellulose aqueous solution.

[0057] The modified highly water-miscible phenolic resin emulsion of the present invention has a non-volatile matter content of 25-55wt%, preferably 35-45wt%; a viscosity of 50-500mPa·s, preferably 100-300mPa·s; a free formaldehyde content of ≤0.3%; a free phenol content of ≤2%, preferably ≤1%; a pH of 6.5-7.8, a weight-average molecular weight of 1000-6000, and can be miscible with water in any proportion.

[0058] The embodiment of the present invention also provides a method for preparing the modified highly water-miscible phenolic resin emulsion, comprising the following steps:

[0059] Weigh the raw materials by weight, mix the formaldehyde aqueous solution with the modifier A, adjust the pH to alkaline, carry out the first heat preservation reaction, add phenol and catalyst after the reaction, adjust the pH of the mixture to near neutral after the polycondensation reaction, add emulsifier and water for emulsification reaction, add modifier B after the reaction, carry out the second heat preservation reaction, and obtain the modified highly water-miscible phenolic resin emulsion.

[0060] In a preferred embodiment of the present invention, the temperature of the first insulation reaction is 80-90° C., and the insulation time is 30-60 minutes.

[0061] In a preferred embodiment of the present invention, the temperature of the second insulation reaction is 50-70° C., and the insulation time is 1-2 hours.

[0062] In a preferred embodiment of the present invention, the temperature of the polycondensation reaction is 70-90° C., and the viscosity of the mixture after the polycondensation reaction is 200-500 mPa·s.

[0063] In a preferred embodiment of the present invention, an emulsifier and water are added and the reaction is continued at 55-75° C. for 1-3 hours.

[0064] In a preferred embodiment of the present invention, the formaldehyde aqueous solution is mixed with the modifier A and the pH is adjusted to 9.0-9.5.

[0065] In a preferred embodiment of the present invention, the pH of the mixture is adjusted to 6.5-7.5 after the polycondensation reaction.

[0066] In a preferred embodiment of the present invention, the formaldehyde aqueous solution is mixed with the modifier A, and the pH is adjusted with sodium hydroxide and / or potassium hydroxide.

[0067] In a preferred embodiment of the present invention, after the polycondensation reaction, the pH of the mixture is adjusted with an acid, wherein the acid comprises one or more of p-toluenesulfonic acid, sulfuric acid, boric acid, phosphoric acid, acetic acid and formic acid. Exemplarily, the acid used is p-toluenesulfonic acid, sulfuric acid or boric acid.

[0068] All raw materials used in the examples of the present invention are commercially available.

[0069] The technical solution of the present invention is further illustrated by the following embodiments.

[0070] Example 1

[0071] The preparation method of a modified highly water-miscible phenolic resin emulsion in this embodiment comprises the following steps:

[0072] (1) Weigh the following raw materials respectively: 100 kg of formaldehyde aqueous solution, 65 kg of phenol, 4 kg of catalyst (sodium hydroxide), 17 kg of modifier A (melamine), 6 kg of modifier B (urea), and 4 kg of emulsifier (sorbitan laurate);

[0073] (2) 100 kg of a 50% formaldehyde aqueous solution was mixed with 17 kg of a modifier A (melamine), and the pH was adjusted to 9.3 with sodium hydroxide. The mixture was kept warm at 85° C. for 45 minutes. After the reaction, 65 kg of phenol and 4 kg of a catalyst (sodium hydroxide) were added. The mixture was polycondensed at 80° C. until the viscosity reached 350 mPa·s. A mixture was obtained. The pH of the mixture was adjusted to 7.0 with p-toluenesulfonic acid. 4 kg of an emulsifier (sorbitan laurate) and 110 kg of water were added. The mixture was emulsified at 65° C. for 2 hours. After the reaction, 6 kg of a modifier B (urea) was added. The mixture was kept warm at 60° C. for 1.5 hours. A modified highly water-miscible phenolic resin emulsion was obtained.

[0074] The modified highly water-miscible phenolic resin emulsion prepared in Example 1 of the present invention has a non-volatile matter content of 41wt%, a viscosity of 200mPa·s, a free formaldehyde content of 0.15%, a free phenol content of 0.83%, a pH of 7.02, a weight-average molecular weight of 1800, and is miscible with water in any proportion.

[0075] Figure 1 This is a physical picture of the modified highly water-miscible phenolic resin emulsion prepared in Example 1 of the present invention. Figure 2 This figure shows the appearance of the modified highly water-miscible phenolic resin emulsion prepared in Example 1 of the present invention after adding 10 times of water to dilute it. As can be seen from the figure, the modified highly water-miscible phenolic resin emulsion prepared in Example 1 of the present invention is still a uniform emulsion after being mixed with water. The modified highly water-miscible phenolic resin emulsion prepared in Example 1 of the present invention has good water miscibility.

[0076] Example 2

[0077] The preparation method of a modified highly water-miscible phenolic resin emulsion in this embodiment comprises the following steps:

[0078] (1) Weigh the following raw materials respectively: 100 kg of formaldehyde aqueous solution, 50 kg of phenol, 2 kg of catalyst (potassium hydroxide), 20 kg of modifier A (dicyandiamide), 10 kg of modifier B (urea), and 2 kg of emulsifier (nonylphenol polyether-10);

[0079] (2) 100 kg of a 50% formaldehyde aqueous solution was mixed with 20 kg of a modifier A (dicyandiamide), the pH was adjusted to 9.5 with potassium hydroxide, and the mixture was kept warm for reaction at 90° C. for 30 minutes. After the reaction, 50 kg of phenol and 2 kg of a catalyst (potassium hydroxide) were added, and a polycondensation reaction was carried out at 90° C. until the viscosity of the mixture was 200 mPa·s. Thereafter, the pH of the mixture was adjusted to 7.5 with sulfuric acid, and 2 kg of an emulsifier (nonylphenol polyether-10) and 150 kg of water were added, and an emulsification reaction was carried out at 75° C. for 1 hour. After the reaction, 10 kg of a modifier B (urea) was added, and the mixture was kept warm for reaction at 50° C. for 2 hours to obtain a modified highly water-miscible phenolic resin emulsion.

[0080] The modified highly water-miscible phenolic resin emulsion prepared in Example 2 of the present invention has a non-volatile matter content of 35wt%, a viscosity of 100mPa·s, a free formaldehyde content of 0.15%, a free phenol content of 0.45%, a pH of 7.55, a weight-average molecular weight of 1000, and is miscible with water in any proportion.

[0081] Example 3

[0082] The preparation method of a modified highly water-miscible phenolic resin emulsion in this embodiment comprises the following steps:

[0083] (1) Weigh the following raw materials respectively: 100 kg of formaldehyde aqueous solution, 80 kg of phenol, 6 kg of catalyst (triethylamine), 14 kg of modifier A (melamine), 2 kg of modifier B (ethylene urea), and 6 kg of emulsifier (polysorbate 20);

[0084] (2) 100 kg of a 50% formaldehyde aqueous solution was mixed with 14 kg of a modifier A (melamine), and the pH was adjusted to 9.0 with sodium hydroxide. The mixture was kept warm at 80°C for 60 minutes. After the reaction, 80 kg of phenol and 6 kg of a catalyst (triethylamine) were added. The mixture was polycondensed at 70°C until the viscosity was 500 mPa·s. The pH of the mixture was then adjusted to 6.5 with boric acid. 6 kg of an emulsifier (polysorbate-20) and 70 kg of water were added. The mixture was emulsified at 55°C for 3 hours. After the reaction, 2 kg of a modifier B (ethylene urea) was added. The mixture was kept warm at 70°C for 1 hour to obtain a modified highly water-miscible phenolic resin emulsion.

[0085] The modified highly water-miscible phenolic resin emulsion prepared in Example 3 of the present invention has a non-volatile matter content of 52wt%, a viscosity of 400mPa·s, a free formaldehyde content of 0.09%, a free phenol content of 1.82%, a pH of 6.64, a weight-average molecular weight of 5000, and is miscible with water in any proportion.

[0086] Comparative Example 1

[0087] The same as Example 1, except that the raw material does not contain an emulsifier, comprises the following steps:

[0088] (1) Weigh the following raw materials respectively: 100 kg of formaldehyde aqueous solution, 65 kg of phenol, 4 kg of catalyst (sodium hydroxide), 17 kg of modifier A (melamine), and 6 kg of modifier B (urea);

[0089] (2) 100 kg of a 50% formaldehyde aqueous solution was mixed with 17 kg of a modifier A (melamine), the pH was adjusted to 9.3 with sodium hydroxide, and the mixture was kept warm at 85° C. for 45 minutes. After the reaction, 65 kg of phenol and 4 kg of a catalyst (sodium hydroxide) were added, and a polycondensation reaction was carried out at 80° C. until the viscosity was 350 mPa·s to obtain a mixture. Thereafter, the pH of the mixture was adjusted to 7.0 with p-toluenesulfonic acid, 110 kg of water was added, and an emulsification reaction was carried out at 65° C. for 2 hours. After the reaction, 6 kg of a modifier B (urea) was added, and the mixture was kept warm at 60° C. for 1.5 hours to obtain a modified phenolic resin.

[0090] The modified phenolic resin prepared in Comparative Example 1 of the present invention has a non-volatile content of 41wt%, a viscosity of 180mPa·s, a free formaldehyde content of 0.15%, a free phenol content of 0.84%, a pH of 7.03, a weight average molecular weight of 1800, and a water miscibility of 0.5.

[0091] Figure 3 This is an appearance diagram of the modified phenolic resin prepared in Comparative Example 1 of the present invention after adding 10 times of water for dilution. As can be seen from the figure, serious stratification occurs. The modified phenolic resin prepared in Comparative Example 1 of the present invention has poor water solubility.

[0092] Comparative Example 2

[0093] The same as Example 1, except that the order of adding the emulsifier is different, comprises the following steps:

[0094] (1) Weigh the following raw materials respectively: 100 kg of formaldehyde aqueous solution, 65 kg of phenol, 4 kg of catalyst (sodium hydroxide), 17 kg of modifier A (melamine), 6 kg of modifier B (urea), and 4 kg of emulsifier (sorbitan laurate);

[0095] (2) 100 kg of a 50% formaldehyde aqueous solution, 17 kg of a modifier A (melamine) and 4 kg of an emulsifier (sorbitan laurate) were mixed, the pH was adjusted to 9.3 with sodium hydroxide, and the mixture was kept warm at 85°C for 45 minutes. After the reaction, 65 kg of phenol and 4 kg of a catalyst (sodium hydroxide) were added, and a polycondensation reaction was carried out at 80°C until the viscosity of the mixture was 350 mPa·s. Thereafter, the pH of the mixture was adjusted to 7.0 with p-toluenesulfonic acid, and 110 kg of water was added. The mixture was continued to react at 65°C for 2 hours. After the reaction, 6 kg of a modifier B (urea) was added, and the mixture was kept warm at 60°C for 1.5 hours to obtain a modified phenolic resin emulsion.

[0096] The modified phenolic resin emulsion prepared in Comparative Example 2 of the present invention has a non-volatile content of 41wt%, a viscosity of 220mPa·s, a free formaldehyde content of 0.14%, a free phenol content of 0.80%, a pH of 7.03, a weight average molecular weight of 1850, and a water miscibility of 1. Compared with Example 1, the water miscibility is poor.

[0097] Comparative Example 3

[0098] The same as Example 1, except that the raw material does not contain modifier A (melamine), comprises the following steps:

[0099] (1) Weigh the following raw materials respectively: 100 kg of formaldehyde aqueous solution, 65 kg of phenol, 4 kg of catalyst (sodium hydroxide), 6 kg of modifier B (urea), and 4 kg of emulsifier (sorbitan laurate);

[0100] (2) 100 kg of a 50% formaldehyde aqueous solution was added to a reactor, the pH was adjusted to 9.3 with sodium hydroxide, and the mixture was kept warm at 85° C. for 45 minutes. After the reaction, 65 kg of phenol and 4 kg of a catalyst (sodium hydroxide) were added, and a polycondensation reaction was carried out at 80° C. until the viscosity was 350 mPa·s to obtain a mixture. Thereafter, the pH of the mixture was adjusted to 7.0 with p-toluenesulfonic acid, and 4 kg of an emulsifier (sorbitan laurate) and 110 kg of water were added, and an emulsification reaction was carried out at 65° C. for 2 hours. After the reaction, 6 kg of a modifier B (urea) was added, and the mixture was kept warm at 60° C. for 1.5 hours to obtain a modified phenolic resin emulsion.

[0101] The modified phenolic resin emulsion prepared in Comparative Example 3 of the present invention has a non-volatile content of 40wt%, a viscosity of 150mPa·s, a free formaldehyde content of 0.45%, a free phenol content of 0.80%, a pH of 7.02, a weight average molecular weight of 1600, and a water miscibility of 2. Compared with Example 1, the free formaldehyde content is increased by 2 times, and the water miscibility is poor.

[0102] Comparative Example 4

[0103] The same as Example 1, except that the raw material does not contain modifier B (urea), comprises the following steps:

[0104] (1) Weigh the following raw materials respectively: 100 kg of formaldehyde aqueous solution, 65 kg of phenol, 4 kg of catalyst (sodium hydroxide), 17 kg of modifier A (melamine), and 4 kg of emulsifier (sorbitan laurate);

[0105] (2) 100 kg of a 50% formaldehyde aqueous solution was mixed with 17 kg of a modifier A (melamine), the pH was adjusted to 9.3 with sodium hydroxide, and the mixture was kept warm at 85° C. for 45 minutes. After the reaction, 65 kg of phenol and 4 kg of a catalyst (sodium hydroxide) were added, and a polycondensation reaction was carried out at 80° C. until the viscosity of the mixture was 350 mPa·s. Thereafter, the pH of the mixture was adjusted to 7.0 with p-toluenesulfonic acid, and 4 kg of an emulsifier (sorbitan laurate) and 110 kg of water were added. The mixture was emulsified at 65° C. for 2 hours to obtain a phenolic resin emulsion.

[0106] The phenolic resin emulsion prepared in Comparative Example 4 of the present invention has a non-volatile matter of 41wt%, a viscosity of 210mPa·s, a free formaldehyde content of 0.43%, a free phenol content of 0.83%, a pH of 7.00, a weight average molecular weight of 1800, and is miscible with water in any proportion. Compared with Example 1, the free formaldehyde content is increased by 4.5 times.

[0107] Comparative Example 5

[0108] The solvent-type phenolic resin has methanol as solvent, a non-volatile content of 42wt%, a viscosity of 180mPa·s, a free formaldehyde content of 0.05%, a free phenol content of 7.92%, a pH of 7.02, a weight average molecular weight of 1800, and is miscible with methanol in any proportion.

[0109] Comparative Example 6

[0110] The conventional water-based phenolic resin used for impregnation has a non-volatile content of 41 wt%, a viscosity of 55 mPa·s, a free formaldehyde content of 0.35%, a free phenol content of 1.78%, a pH of 9.20, a weight-average molecular weight of 650, and is miscible with water in any proportion.

[0111] Effect Example 1

[0112] 100 parts of the modified highly water-miscible phenolic resin emulsion obtained in Example 1, 150 parts of water, 0.3 parts of silane, 5 parts of blue color paste, 5 parts of 5% polyvinyl alcohol (PVA-1788) aqueous solution, and 5 parts of acrylic emulsion were mixed and stirred for 30 minutes. After standing for 1 hour, the uniformity of the liquid was observed under a microscope. Figure 4As shown in (a), it can be seen from the figure that the materials in the mixed liquid are distributed relatively evenly, and no particles or aggregation are seen.

[0113] The modified highly water-miscible phenolic resin emulsion was replaced with the modified phenolic resin of Comparative Example 1 and mixed with the materials. Figure 4 As shown in (b), it can be seen from the figure that the material distribution is uneven, and there are particles and aggregates. From the above results, it can be seen that the modified highly water-miscible phenolic resin emulsion obtained in Example 1 of the present invention has good miscibility with auxiliary materials such as silane, polyol, and color paste.

[0114] Application Example 1

[0115] The modified highly water-miscible phenolic resin emulsion obtained in Example 1 was used to prepare air filter paper:

[0116] The modified highly water-miscible phenolic resin emulsion obtained in Example 1 and the acrylic emulsion were mixed evenly in a mass ratio of 9:1, and then water was added to adjust the solid content to 20%, poured into the glue tank, and double rollers were used to apply glue evenly on 100gsm wood pulp paper, with a coating amount of 25g / m 2 , dried at 160°C for 15 min, and rolled up to obtain air filter paper.

[0117] When the modified highly water-miscible phenolic resin emulsion was replaced with the modified phenolic resin of Comparative Example 1, phase separation occurred due to poor water miscibility, and air filter paper could not be prepared.

[0118] The modified highly water-miscible phenolic resin emulsion was replaced with the solvent-based phenolic resin of Comparative Example 5, and methanol was used to dilute the resin instead of water to prepare air filter paper.

[0119] The modified highly water-miscible phenolic resin emulsion was replaced with the conventional water-based phenolic resin used for impregnation in Comparative Example 6 to prepare air filter paper.

[0120] The performance of the air filter paper prepared by the resin prepared in Example 1, Comparative Example 5 and Comparative Example 6 was tested. The stiffness of the filter paper was tested according to GB / T 2679.3-1996 "Test for stiffness of paper and paperboard"; the bursting resistance was tested according to GB / T454-2002 "Determination of bursting resistance of paper"; the air permeability was tested according to QB / T 1461-1992 "Determination of air permeability of highly air permeable paper". The results are shown in Table 1.

[0121] Table 1 Air filtration filter paper performance test results

[0122] Test items Example 1 Comparative Example 5 Comparative Example 6 <![CDATA[Coating amount (g / m 2 )]]> 25.2 25.3 25.0 color off white off white Brown Stiffness (mN·m) 8.23 8.12 12.2 Burst strength(kPa) 376 365 300 <![CDATA[Air permeability (L / m 2 ·s)]]> 12.6 12.4 12.3

[0123] As can be seen from Table 1, the performances of the air filter paper prepared by the modified phenolic resin emulsion prepared by Example 1 and the solvent-based phenolic resin prepared by Comparative Example 5 are similar, the color is light, and the use requirements of the air filter paper are met, but Comparative Example 1 contains about 50% methanol, the VOC content is high, and the harm to the environment and human body is large. The modified high water miscible phenolic resin emulsion of Example 1 is more environmentally friendly. Compared with Comparative Example 6 (traditional water-based phenolic resin), the air filter paper prepared by the modified phenolic resin emulsion prepared by Example 1 has lower stiffness, higher bursting resistance, and lighter color, which is more suitable for the use of air filter paper.

[0124] Application Example 2

[0125] The modified highly water-miscible phenolic resin emulsion obtained in Example 2 was used to prepare wet curtain paper:

[0126] Add 3 times the volume of softened water to the modified highly water-miscible phenolic resin emulsion obtained in Example 2, mix well, and evenly impregnate kraft paper. The glue amount is 15g / m 2 , dried at 90℃ for 10s, pressed and shaped by edge forming machine at 260℃ for about 3s, and then put into drying oven at 240℃ for 30s to make corrugated paper. Two layers of glue are applied on one side of the corrugated paper, and then stacked together to make paper piles. Push into secondary curing oven, cure at 115℃ for 15min, cut and polish to get wet curtain paper, the real thing is as follows Figure 5 shown.

[0127] The wet curtain paper prepared by the above method was tested according to NY / T 2707-2015 "Technical Specifications for Quality Evaluation of Paper Wet Curtains". The results showed that the water absorption rate was greater than 95%, the water absorption rate was 75mm / 10min, and the compressive strength and peel strength met the requirements.

[0128] Application Example 3

[0129] The modified highly water-miscible phenolic resin emulsion obtained in Example 3 was used to prepare plywood:

[0130] The modified highly water-miscible phenolic resin emulsion obtained in Example 3 was mixed with flour in a mass ratio of 100:5 and evenly coated on a 1.7 mm thick eucalyptus veneer. The moisture content of the eucalyptus veneer was controlled to be 10%, and the amount of glue was 300 g / m 2 After coating, the veneer is assembled in the direction of vertical staggered wood grain. The number of veneer layers is 5. After aging for 30 minutes, it is put into the press for pressing at room temperature for 30 minutes. After aging for another 30 minutes, it is put into the press at 125℃ for hot pressing for 10 minutes to obtain plywood. The actual product is as follows Figure 6 shown.

[0131] According to the standard GB / T 17657-2022 "Test methods for physical and chemical properties of wood-based panels and veneer wood-based panels", the immersion peel strength and formaldehyde emission of plywood were tested. The immersion peel strength passed the Class I board conditions test, and the formaldehyde emission was 0.21 mg / L (dryer method).

[0132] Application Example 4

[0133] The modified highly water-miscible phenolic resin emulsion obtained in Example 2 was used to prepare impregnated coated paper:

[0134] 100 kg of the modified highly water-miscible phenolic resin emulsion obtained in Example 2 is placed in a mixing tank, 1.5 kg of emulsified methyl silicone oil and 1.6 kg of paraffin emulsion are added, and the mixture is stirred and mixed at a rate of 600 r / min to obtain a water-based phenolic resin emulsion impregnated adhesive. The impregnated adhesive is injected into a special adhesive tank for impregnation to form a flow cycle. The kraft paper runs under the traction of the mechanical equipment and passes through the water-based phenolic resin emulsion impregnated adhesive. The adhesive temperature is 30°C. The amount of adhesive is controlled by a metering roller, and then passes through an oven with different temperature zones and is cooled to obtain an impregnated coated paper. The impregnated coated paper obtained above is subjected to regional segmented drying. The oven drying zones in different temperature zones are divided into three controlled temperature sections, namely, a low temperature zone (110°C), a medium temperature zone (120-130°C), and a high temperature zone (140°C). The operating rate is 45 m / min, and the cooling section temperature is 30°C. The obtained modified phenolic emulsion impregnated coated paper (such as the actual object) is Figure 7 As shown), the glue content of the film paper is 68%, the volatile matter content is 8%, the finished product is a soft film, and the base material is kraft paper color.

[0135] The modified phenolic emulsion impregnated coated paper prepared above was hot pressed and laminated on the surface of the fiberboard to obtain a decorative protective layer with light color and uniform texture. The product was tested for relevant properties according to the standard GB / T 15102-2017 "Impregnated Film Paper Veneer Fiberboard and Particleboard", and the results are shown in Table 2.

[0136] Table 2 Performance test results of impregnated coated paper

[0137]

[0138] It can be seen from Table 2 that various performance tests of the impregnated coated paper prepared in Example 2 of the present invention meet the requirements.

[0139] The above are only preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A modified highly water-miscible phenolic resin emulsion, characterized in that: The raw materials include, by weight: 100 parts of formaldehyde aqueous solution, 50-80 parts of phenol, 2-6 parts of catalyst, 14-20 parts of modifier A, 2-10 parts of modifier B and 2-6 parts of emulsifier; The modifier A is melamine and / or dicyandiamide; The modifier B is urea and / or ethylene urea.

2. The modified highly water-miscible phenolic resin emulsion according to claim 1, characterized in that: The catalyst is selected from one or more of sodium hydroxide, potassium hydroxide, lithium hydroxide, calcium hydroxide, barium hydroxide, calcium oxide, ammonia water, triethylamine, dipropylenediamine and dimethylethanolamine.

3. The modified highly water-miscible phenolic resin emulsion according to claim 1, characterized in that: The emulsifier is selected from one or more of polyoxyethylene ethers, polyol monofatty acid esters and modified cellulose nonionic surfactants.

4. The modified highly water-miscible phenolic resin emulsion according to claim 3, characterized in that: The polyoxyethylene ether nonionic surfactant is selected from one or more of fatty alcohol polyoxyethylene ethers, alkylphenol polyoxyethylene ethers and polyol polyoxyethylene ether fatty acid esters; The polyol mono-fatty acid ester nonionic surfactant is selected from one or more of glycerol fatty acid ester, sorbitan ester and sucrose fatty acid ester; The modified cellulose nonionic surfactant is one or more of hydroxyethyl cellulose aqueous solution, hydroxypropyl cellulose aqueous solution and methyl cellulose aqueous solution.

5. A method for preparing a modified highly water-miscible phenolic resin emulsion according to any one of claims 1 to 4, characterized in that: The following steps are involved: Weigh the raw materials by weight, mix the formaldehyde aqueous solution with the modifier A, adjust the pH to alkaline, carry out the first heat preservation reaction, add phenol and catalyst after the reaction, adjust the pH of the mixture to near neutral after the polycondensation reaction, add emulsifier and water for emulsification reaction, add modifier B after the reaction, carry out the second heat preservation reaction, and obtain the modified highly water-miscible phenolic resin emulsion.

6. The method for preparing the modified highly water-miscible phenolic resin emulsion according to claim 5, characterized in that: The temperature of the first insulation reaction is 80-90° C. and the insulation time is 30-60 minutes; and / or, The temperature of the second heat preservation reaction is 50-70° C. and the heat preservation time is 1-2 hours; and / or, The temperature of the polycondensation reaction is 70-90° C., and the viscosity of the mixture after the polycondensation reaction is 200-500 mPa·s; and / or, Add emulsifier and water and emulsify and react at 55-75°C for 1-3 hours.

7. The method for preparing the modified highly water-miscible phenolic resin emulsion according to claim 5, characterized in that: Mixing the formaldehyde aqueous solution with the modifier A and adjusting the pH to 9.0-9.5; and / or, After the polycondensation reaction, the pH of the mixture was adjusted to 6.5-7.

5.

8. The method for preparing the modified highly water-miscible phenolic resin emulsion according to claim 7, characterized in that: Mixing the formaldehyde aqueous solution with the modifier A, and adjusting the pH with sodium hydroxide and / or potassium hydroxide; After the polycondensation reaction, the pH of the mixture is adjusted with an acid, wherein the acid comprises one or more of p-toluenesulfonic acid, sulfuric acid, boric acid, phosphoric acid, acetic acid and formic acid.

9. Application of the modified highly water-miscible phenolic resin emulsion according to any one of claims 1 to 4 in the fields of paper products, artificial boards, abrasives and tools, and composite materials.

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