WO2013020344A1

WO2013020344A1 - Water-soluble modified melamine-formaldehyde impregnating resin, preparation method therefor and use thereof

Info

Publication number: WO2013020344A1
Application number: PCT/CN2011/084796
Authority: WO
Inventors: 任力
Original assignee: 华南理工大学
Priority date: 2011-08-05
Filing date: 2011-12-28
Publication date: 2013-02-14
Also published as: CN102391616A; CN102391616B

Abstract

Disclosed are a water-soluble modified melamine-formaldehyde impregnating resin, a preparation method therefor, and a use thereof. The steps are as follows: preparing a water-soluble methyl etherified melamine-formaldehyde resin an addition polycondensation reaction of formaldehyde and melamine, etherifying with methanol, and compounding with an osmotic agent and a formaldehyde-removing agent such as urea; preparing a water-soluble acrylic ester emulsion toughening agent through an emulsion polymerization method using acrylic ester monomers and styrene; and preparing a water-soluble polyurethane emulsion modification agent through a self-emulsification method using toluene diisocynate, polyether dihydroxy propionic acid, and ethylene diamine; and mixing the three resins at a certain weight ratio to obtain the water-soluble modified melamine-formaldehyde resin of the present invention. The resin is applicable to the impregnation of paper edge banding and decorative paper in the furniture and paper-making industries, and has the advantages of good flexibility, low formaldehyde residue, and stability in a long term. The preparation process of the present invention is simple, which prevents the risk and pollution caused by the diffusion of hazardous solvents, and achieves green production, energy saving, and emission reduction.

Description

Water-soluble modified melamine formaldehyde impregnating resin and preparation method and application thereof

Technical field

The invention relates to a water-soluble modified melamine formaldehyde impregnating resin which can be used in the furniture and paper industry, such as paper edge strips and decorative paper, and a preparation method thereof, and belongs to the fields of furniture manufacturing and paper making.

Background technique

Melamine formaldehyde resin is a thermosetting resin. It has flame retardant, water resistance, heat resistance, aging resistance, arc resistance, chemical resistance, good insulation properties, gloss and mechanical strength. It is widely used in wood furniture and plastics. Coatings, paper, textile, leather, electrical, pharmaceutical and other industries. However, its shortness of brittleness, short shelf life, toxicity of organic solvents and high volatility limit its further wide application. To this end, research on its modification has become a hot topic.

At present, the modification methods can be divided into physical modification and chemical modification. The main purpose is to change the former oil-soluble resin into water-soluble resin, reduce the disadvantages of organic solvent toxicity and volatility, increase toughness, reduce formaldehyde content and Improve resin stability, physical modification mainly by adding some flexible polymers to increase the toughness of melamine formaldehyde resin, such as silicone, polyvinyl alcohol, polyacrylamide and polyvinyl acetate, etc., chemical modification mainly through melamine formaldehyde In the prepolymerization process of the resin, reactive molecules such as alcohols and urea are added to improve water solubility, reduce formaldehyde content, and improve resin stability. At present, the modification of the resin is often carried out by a modification means, the modification effect can only achieve a modification purpose and often improves the performance on the one hand, and loses other excellent properties, such as adding only flexibility. The polymer toughening agent can not improve the stability of the resin, and often loses its excellent properties such as good surface hardness and wear resistance.

Summary of the invention

The object of the present invention is to overcome the shortcomings of the prior art, and to modify a physical and chemical modification method to provide a comprehensive performance with good toughness, low formaldehyde content and long-term stability. Water-soluble modified melamine formaldehyde impregnating resin and preparation method thereof.

The above object of the present invention is achieved by the following technical solutions:

The preparation method of water-soluble modified melamine formaldehyde impregnating resin adopts water-soluble methyl etherified melamine formaldehyde resin as matrix, water-soluble acrylate emulsion and water-soluble polyurethane emulsion as toughening agent and modifier respectively, and composite preparation Out, the specific steps are as follows:

(1) Preparation of water-soluble methyl etherified melamine formaldehyde resin:

The raw material formula is: 30-40% of melamine, 20-30% of formaldehyde, 40-50% of methanol according to the weight percentage, and formaldehyde and melamine are weighed according to the above ratio, at 50-60 oC, pH=8-9 for 30-120 minutes, then warm to 80-90 oC Adding methanol under the condition of PH=6-7, reacting for 30-120 minutes to obtain a water-soluble methyl etherified melamine formaldehyde resin;

(2) Preparation of water-soluble acrylate emulsion toughening agent:

The raw material formula is: in terms of weight percent, acrylate monomer 36-56%, 40-60% styrene, 2-3% emulsifier, 0.5-1.5% initiator; initiator, all the above monomers (acrylic acid) The ester monomer and styrene) and part of the emulsifier and deionized water are mixed for pre-emulsification; then the remaining emulsifier is dissolved in deionized water at 70-80 oC, under nitrogen protection, the pre-emulsion of the above monomer is added to the above solution to react for 2-4 hours, then the temperature is lowered to 60-70 oC, and ammonia water is added for adjustment. PH=8.0, to obtain a water-soluble acrylate emulsion toughening agent;

(3) Preparation of water-soluble polyurethane emulsion modifier:

The raw material formula is: 25-40% by weight of toluene diisocyanate, 55-70% of polyether, 1-4% of dimethylolpropionic acid, 3-5% of ethylenediamine; toluene diisocyanate, polyether , dimethylolpropionic acid at 80 Pre-polymerization reaction at oC for 3-4 hours, cooling to 10-30 oC, adding deionized water to emulsify, adding ethylenediamine chain extension reaction for 1-1.5 hours to obtain a water-soluble polyurethane emulsion modifier;

(4) The water-soluble methyl etherified melamine formaldehyde resin, the acrylate emulsion toughening agent and the polyurethane emulsion modifier prepared above are respectively carried out in terms of weight percentage: 50 to 90%, 5 to 30%, and 0 to 20%. Mixing, that is, producing a water-soluble modified melamine formaldehyde resin.

Preferably, the water-soluble methyl etherified melamine formaldehyde resin, the acrylate emulsion toughening agent and the polyurethane emulsion modifier are 50 to 90%, 5 to 20% and 0 to 10%, respectively, by weight.

Preferably, the acrylate monomer is methyl methacrylate 10-37%, butyl acrylate 54-85% And a mixture of 0-17% acrylic acid.

Preferably, the emulsifier is a mixture of one or both of sodium lauryl sulfate and nonylphenol ethoxylate.

Preferably, the initiator is a mixture of one or both of potassium persulfate and ammonium persulfate.

Preferably, the partial emulsifier added in the pre-emulsification in the step (2) is 10 to 90% of the total amount of the emulsifier.

Preferably, in step (1), a pull-up powder (sodium butyl naphthalenesulfonate) of 0.05-1% by weight of the total amount of the raw materials is further added.

Preferably, the reaction of step (1) is finally added with 0.05-5% urea or emulsified rosin in total weight of the raw materials.

The water-soluble modified melamine formaldehyde impregnating resin prepared by the above method is used for impregnation of paper edge strips and decorative paper in furniture and papermaking.

Compared with the prior art, the invention has the following advantages:

(1) The water-soluble modified melamine formaldehyde impregnating resin of the invention has good flexibility, and is particularly suitable for impregnation of paper edge strips and decorative papers in furniture and papermaking, and the paper edge strips prepared can be rotated at any angle of 0-180o. The surface coating hardness is up to H grade (pencil hardness) and can be stored for 6 months at room temperature.

(2) The water-soluble melamine formaldehyde impregnating resin of the present invention has long-term stability and can be stored for 3 to 6 months.

(3) The water-soluble modified melamine formaldehyde impregnating resin of the invention is an environment-friendly material, and the residual formaldehyde content is less than the national standard 1.3 Mg/kg. The problem of high toxicity and high volatility and high residual formaldehyde content of the organic solvent used in the oil-soluble impregnating resin has been improved, and environmentally-friendly green production has been achieved, thereby achieving energy saving and emission reduction.

(4) The process adopted by the invention is simple and is advantageous for large-scale production.

DRAWINGS

Figure 1 is an infrared spectrum of a water-soluble methyl etherified melamine formaldehyde resin.

Figure 2 is an infrared spectrum of a water-soluble acrylate emulsion toughening agent.

Figure 3 is an infrared spectrum of a water-soluble polyurethane modifier.

detailed description

For a better understanding of the present invention, the present invention will be further described with reference to the embodiments, but the scope of the invention is not limited to the scope of the embodiments.

Example 1

Step 1: Preparation of water-soluble methyl etherified melamine formaldehyde resin:

Weigh 175g of melamine, 112.2g of formaldehyde, and add it to the reactor at 50 °C to adjust PH=8.5. Reaction for 30 minutes, warming to 85 oC Weighed 212g of methanol and added it to the reactor to adjust the pH to 6.5. After reacting for 30 minutes, 5 g of urea was added to 30 ° C and 0.3 g of the opened powder was added to obtain the desired water-soluble methyl etherified melamine formaldehyde resin.

Step 2: Preparation of water-soluble acrylate emulsion toughening agent:

Methyl methacrylate 12g, butyl acrylate 30g, acrylic acid 2g, styrene 54g, emulsifier (sodium lauryl sulfate) 2g, initiator (potassium persulfate) 0.6g, the synthesis process is: the above initiator, all monomers Pre-emulsified with 1.6g emulsifier and 100mL deionized water; the remaining 0.4g emulsifier, 50ml deionized water was stirred and dissolved in the reactor and heated to 75oC, and the monomer pre-emulsion was added to the above reaction under the protection of nitrogen. Reaction in the solution for 3 hours, cooling to 65 oC, add water to adjust the pH = 8.0, and discharge to room temperature to prepare a water-soluble acrylate emulsion toughening agent.

Step 3: Preparation of water-soluble polyurethane emulsion modifier:

Weigh 105g of toluene diisocyanate, 180g of polyether, 6g of dimethylolpropionic acid and 9g of ethylenediamine. The synthesis process is as follows: adding toluene diisocyanate, polyether and dimethylolpropionic acid to the reactor at 80 The prepolymerization reaction was carried out for 3.5 hours at oC, and the temperature was lowered to 25 ° C, emulsified by adding 100 mL of deionized water, and 9 g of ethylenediamine was added for chain extension reaction for 1 hour, and a water-soluble polyurethane emulsion modifier was prepared by discharging.

Step 4: 180 g of the water-soluble methyl etherified melamine formaldehyde resin, 54 g of the acrylate emulsion toughening agent and 18 g of the polyurethane emulsion modifier are mixed to obtain a water-soluble modified melamine formaldehyde resin. It is used for the impregnation of edge banding paper. It has good flexibility. It is easy to rotate in the edge of furniture (0-180o), the surface coating hardness is H grade (pencil hardness), it can be stored for 6 months at room temperature, residual formaldehyde content. 1.1 Mg/kg.

Example 2

Weigh 175 g of melamine, 112.2 g of formaldehyde, and add to the reactor at 50 ° C, adjust pH = 8.5, and react for 30 minutes. The temperature was raised to 85 oC and 212 g of methanol was weighed and added to the reactor to adjust the pH to 6.5. After reacting for 30 minutes, 10 g of urea was added to room temperature and 0.4 g of the opened powder was added to obtain the desired water-soluble methyl etherified melamine formaldehyde resin.

Step 2: Preparation of water-soluble acrylate emulsion toughening agent:

Weigh 15g of methyl methacrylate, 27g of butyl acrylate, 2g of acrylic acid, 55g of styrene, emulsifier (sodium dodecyl sulfate) 2.5 g, initiator (ammonium persulfate) 0.6g, the synthesis process is: the above initiator, all monomers (99g total) and 2g emulsifier and 100mL deionized water pre-emulsified; remaining 0.5g emulsifier, 50ml Deionized water was stirred and dissolved in the reactor and heated to 75 ° C. The monomer pre-emulsion was added to the reactor solution under nitrogen for 3 hours, and the temperature was lowered to 65. oC, add water to adjust the pH = 8.0, and discharge to room temperature to prepare a water-soluble acrylate emulsion toughening agent.

Step 3: Preparation of water-soluble polyurethane emulsion modifier:

Weigh 105g of toluene diisocyanate, 180g of polyether, 6g of dimethylolpropionic acid and 9g of ethylenediamine. The synthesis process is as follows: adding toluene diisocyanate, polyether and dimethylolpropionic acid to the reactor at 80 Prepolymerization at oC for 3.5 hours, cooling to 25 oC, emulsification by adding 100 mL of deionized water, adding ethylenediamine chain extension reaction for 1 hour, and discharging to obtain a water-soluble polyurethane emulsion modifier.

Step 4: 180 g of the water-soluble methyl etherified melamine formaldehyde resin, 36 g of the acrylate emulsion toughening agent and 18 g of the polyurethane emulsion obtained above are mixed to obtain a water-soluble modified melamine formaldehyde resin. It is used for the impregnation of edge banding paper. It has good flexibility. It is easy to rotate in the edge of furniture (0-180o), the surface coating hardness is H grade (pencil hardness), it can be stored for 6 months at room temperature, residual formaldehyde content. 1.0 Mg/kg.

Example 3

Weigh 175 g of melamine, 112.2 g of formaldehyde, and add to the reactor at 50 ° C, adjust pH = 8.5, and react for 30 minutes. The temperature was raised to 85 oC and 212 g of methanol was weighed and added to the reactor to adjust the pH to 6.5. After reacting for 30 minutes, 8 g of urea was added to room temperature and 0.4 g of the opened powder was added to obtain the desired water-soluble methyl etherified melamine formaldehyde resin.

Step 2: Preparation of water-soluble acrylate emulsion toughening agent:

Methyl methacrylate 12g, butyl acrylate 30g, acrylic acid 2g, styrene 55g, emulsifier (nonylphenol ethoxylate) 2.5g, initiator (potassium persulfate) 0.8g, the synthesis process is: the above initiator, all Pre-emulsified monomer (99g total) and 2g emulsifier and 100mL deionized water; the remaining 0.5g emulsifier, 50ml deionized water was stirred and dissolved in the reactor and heated to 75oC, pre-emulsified by nitrogen under the protection of nitrogen The liquid was added to the reactor solution for 3 hours, and the temperature was lowered to 65. oC, add water to adjust the pH = 8.0, and discharge to room temperature to prepare a water-soluble acrylate emulsion toughening agent.

Step 3: Preparation of water-soluble polyurethane emulsion modifier:

Step 4: 180 g of the water-soluble methyl etherified melamine formaldehyde resin, 54 g of the acrylate emulsion toughening agent and 27 g of the polyurethane emulsion obtained above are mixed to obtain a water-soluble modified melamine formaldehyde resin. It is used for the impregnation of edge banding paper. It has good flexibility. It is easy to rotate in the edge of furniture (0-180o), the surface coating hardness is HB grade (pencil hardness), it can be stored for 6 months at room temperature, residual formaldehyde content. 1.0 mg/kg.

Example 4

Weigh 150g of melamine, 100g of formaldehyde, and add it to the reactor at 50oC to adjust PH=8.0. After reacting for 30 minutes, the temperature was raised to 80 ° C, and 249.6 g of methanol was weighed and added to the reactor to adjust the pH to 6.0. After 60 minutes of reaction, the desired water-soluble methyl etherified melamine formaldehyde resin was obtained.

Step 2: Preparation of water-soluble acrylate emulsion toughening agent:

Methyl methacrylate 6g, butyl acrylate 30g, styrene 60g, emulsifier (sodium lauryl sulfate) 3g, initiator (potassium persulfate) 1.0g, the synthesis process is: the above initiator, all monomers and 2g emulsified Pre-emulsified with 100mL of deionized water; 1g of emulsifier remaining, 50ml of deionized water was stirred and dissolved in the reactor and heated to 70oC, and the pre-emulsion of monomer was added to the above reactor solution under nitrogen protection. Hours, cool down to 60 oC, add water to adjust the pH = 8.0, and discharge to room temperature to prepare a water-soluble acrylate emulsion toughening agent.

Step 3: Preparation of water-soluble polyurethane emulsion modifier:

Weigh 75g of toluene diisocyanate, 210g of polyether, 3g of dimethylolpropionic acid and 12g of ethylenediamine. The synthesis process is as follows: adding toluene diisocyanate, polyether and dimethylolpropionic acid to the reactor at 80 Prepolymerization at oC for 3.0 hours, cooling to 10 oC, emulsification by adding 100 mL of deionized water, and adding 12 g of ethylenediamine to carry out chain extension reaction for 1.5 hours, and discharging the water-soluble polyurethane emulsion modifier.

Step 4: 126 g of the water-soluble methyl etherified melamine formaldehyde resin, 75.6 g of the acrylate emulsion toughening agent and 50.4 g of the polyurethane emulsion modifier are mixed to obtain a water-soluble modified melamine formaldehyde resin. It is used for the impregnation of edge banding paper. It has good flexibility. It is easy to rotate in the edge of furniture (0-180o), the surface coating hardness is H grade (pencil hardness), it can be stored for 6 months at room temperature, residual formaldehyde content. 1.2 Mg/kg.

Example 5

Weigh 175g of melamine, 125g of formaldehyde, add it to the reactor at 50oC, adjust the pH=9.0, react for 30 minutes, and heat up to 90. oC was weighed 200 g of methanol and added to the reactor to adjust the pH to 7.0. After 120 minutes of reaction, the desired water-soluble methyl etherified melamine formaldehyde resin was obtained.

Step 2: Preparation of water-soluble acrylate emulsion toughening agent:

Methyl methacrylate 15g, butyl acrylate 35g, acrylic acid 6g, styrene 40g, emulsifier (nonylphenol ethoxylate) 2.5g, initiator (potassium persulfate) 1.5g, the synthesis process is: the above initiator, all The monomer and 2g of emulsifier and 100mL of deionized water were pre-emulsified; the remaining 0.5g of emulsifier, 50ml of deionized water was stirred and dissolved in the reactor and heated to 80oC, and the monomer pre-emulsion was added to the above under nitrogen protection. Reaction in the reactor solution for 4 hours, cooling to 70 oC, add water to adjust the pH = 8.0, and discharge to room temperature to prepare a water-soluble acrylate emulsion toughening agent.

Step 3: Preparation of water-soluble polyurethane emulsion modifier:

Weigh 120g of toluene diisocyanate, 165g of polyether, 6g of dimethylolpropionic acid and 9g of ethylenediamine. The synthesis process is as follows: adding toluene diisocyanate, polyether and dimethylolpropionic acid to the reactor at 80 The reaction was carried out at oC for 4.0 hours, cooled to 30 ° C, emulsified by adding 100 mL of deionized water, and after 9 g of ethylenediamine was added for chain extension, the reaction was carried out for 1 hour, and a water-soluble polyurethane emulsion modifier was obtained by discharging.

Step 4: 226.8 g of the water-soluble methyl etherified melamine formaldehyde resin obtained above and 25.2 g of the acrylate emulsion toughening agent are mixed to obtain a water-soluble modified melamine formaldehyde resin. It is used for the impregnation of edge banding paper. It has good flexibility. It is easy to rotate in the edge of furniture (0-180o), the surface coating hardness is HB grade (pencil hardness), it can be stored for 6 months at room temperature, residual formaldehyde content. 1.1 mg/kg.

Example 6

This example differs from Example 4 in that, in step one, an emulsified rosin is added after the methanol etherification reaction. 8g. In this example, a water-soluble modified melamine formaldehyde resin was obtained. It is used for the impregnation of edge banding paper. It has good flexibility. It is easy to rotate in the edge of furniture (0-180o), the surface coating hardness is H grade (pencil hardness), it can be stored for 6 months at room temperature, residual formaldehyde content. 1.0 Mg/kg.

Claims

Method for preparing water-soluble modified melamine formaldehyde impregnating resin, characterized in that

Including the following steps:

(1) Preparation of water-soluble methyl etherified melamine formaldehyde resin:

The raw material formula is: 30-40% of melamine, 20-30% of formaldehyde, 40-50% of methanol according to the weight percentage, and formaldehyde and melamine are weighed according to the above ratio, at 50-60 oC, pH=8-9 for 30-120 minutes, then warm to 80-90 oC Adding methanol under the condition of PH=6-7, reacting for 30-120 minutes to obtain a water-soluble methyl etherified melamine formaldehyde resin;

(2) Preparation of water-soluble acrylate emulsion toughening agent:

The raw material formula is: in terms of weight percentage, 36-56% of acrylate monomer, 40-60% of styrene, 2-3% of emulsifier, 0.5-1.5% of initiator; initiator, all monomers and parts mentioned above The emulsifier is mixed with deionized water for pre-emulsification; the remaining emulsifier is dissolved in deionized water at 70-80 oC, under nitrogen protection, the pre-emulsion of the above monomer is added to the above solution to react for 2-4 hours, then the temperature is lowered to 60-70 oC, and ammonia water is added for adjustment. PH=8.0, to obtain a water-soluble acrylate emulsion toughening agent;

(3) Preparation of water-soluble polyurethane emulsion modifier:

The raw material formula is: 25-40% by weight of toluene diisocyanate, 55-70% of polyether, 1-4% of dimethylolpropionic acid, 3-5% of ethylenediamine; toluene diisocyanate, polyether , dimethylolpropionic acid at 80 Pre-polymerization reaction at oC for 3-4 hours, cooling to 10-30 oC, adding deionized water to emulsify, adding ethylenediamine chain extension reaction for 1-1.5 hours to obtain a water-soluble polyurethane emulsion modifier;

(4) The water-soluble methyl etherified melamine formaldehyde resin, the acrylate emulsion toughening agent and the polyurethane emulsion modifier prepared above are respectively carried out in terms of weight percentage: 50 to 90%, 5 to 30%, and 0 to 20%. Mixing, that is, producing a water-soluble modified melamine formaldehyde resin.
The preparation method according to claim 1, wherein the water-soluble methyl etherified melamine formaldehyde resin, the acrylate emulsion toughening agent and the polyurethane emulsion modifier are respectively 50 to 90%, 5 to 5% by weight. 20% and 0 to 10%.
The preparation method according to claim 2, wherein the acrylate monomer is methyl methacrylate 10-37%, butyl acrylate 54-85%. And a mixture of 0-17% acrylic acid.
The preparation method according to claim 3, wherein the emulsifier is a mixture of one or both of sodium lauryl sulfate and nonylphenol ethoxylate.
The preparation method according to claim 4, wherein the initiator is a mixture of one or both of potassium persulfate and ammonium persulfate.
The preparation method according to claim 1 or 2 or 3 or 4 or 5, wherein a part of the emulsifier added in the pre-emulsification in the step (2) is 10 to 90% of the total amount of the emulsifier.
The preparation method according to claim 6, characterized in that, in the step (1), a pull-off powder of 0.05 to 1% by weight based on the total weight of the raw materials is further added.
The preparation method according to claim 7, characterized in that, in the step (1), a urea or emulsified rosin having a total weight of the raw materials of 0.05 to 5% is further added.
A water-soluble modified melamine-formaldehyde impregnating resin, which is produced by the method according to any one of claims 1 to 8.
Use of the water-soluble modified melamine-formaldehyde impregnating resin according to claim 9, which is used for impregnation of paper edge strips and decorative paper in furniture and papermaking.