Cyanurotriamide modified urea resin and preparation method thereof
Technical field
The present invention relates to a kind of modified urea-formaldehyde resin and preparation method thereof, relate in particular to a kind of wooden cement template cyanurotriamide modified urea resin and preparation method thereof.
Background technology
Be accompanied by China's rapid economy development, city, farm building develop swift and violent, and the demand of cement formwork increases fast.The wooden cement template obtains owing to it is cheap widely applying.Because synvaren has well water-fast, weathering resistance, therefore, the wooden cement template is with usually using synvaren in the manufacturing of multiplying plywood.But because phenol costs an arm and a leg, also according to height not down, the price of glueing joint goods is higher relatively for the synvaren price.In order to reduce the manufacturing cost of wooden cement template, a lot of factories bring into use cheap urea-formaldehyde resin adhesive.But, poor with the water-fast Joint strength of cement formwork that urea-formaldehyde resin adhesive is made, but cause access times to descend significantly, quality product is difficult to guarantee, and its burst size of methanal height.For the user,,, still be used widely though therefore the latter's nonrecurring cost is more expensive because the cost performance of the cement formwork of urea-formaldehyde resin adhesive manufacturing will be lower than the cement formwork that the resol resin adhesive is made.
Publication number is to disclose a kind of " melamine urea-formaldehyde resin non-dehydrated glue and production method thereof " in the application for a patent for invention of CN1105694A, the urea that adopts in this method and the mol ratio of formaldehyde are 1: 1.3-1.47, trimeric cyanamide weight accounts for the 2.1-5% of weight of urea.But there is the burst size of methanal height in this melamine urea-formaldehyde resin tackiness agent, and resistance to boiling water can be poor, shortcomings such as production cost height.
Summary of the invention
The objective of the invention is at above problems of the prior art, a kind of wooden cement template cyanurotriamide modified urea resin tackiness agent and preparation method thereof is provided, low, cheap, the resistant to boiling water performance height of the burst size of methanal of prepared cyanurotriamide modified urea resin, therefore can substitute the higher synvaren of price, thereby under the prerequisite that guarantees wooden cement template use properties, reduced its manufacturing cost.
For achieving the above object, cyanurotriamide modified urea resin of the present invention is made by following steps:
1) formaldehyde solution is added reactor after, be 3-4 with sour adjust pH;
2) be heated to 45-55 ℃, make formaldehyde activation 15-25 minute, add first urea then, the mol ratio that makes urea and formaldehyde is 1: 2.9-3.5, and reaction is 20-30 minute under 50 ± 5 ℃ of temperature;
3) transfer pH to 7.2-7.8 with sodium hydroxide, add second batch of urea, the mol ratio that makes urea and formaldehyde is 1: 1.9-2.2;
4) in 30-40 minute, slowly be warming up to 90 ± 5 ℃, reacted 40-60 minute;
5) adjust pH reacts to viscosity to 4-6: 25 ℃, be coated with-4 glasss of 22-26 seconds;
6) adjust pH adds the 3rd batch of urea to 7.0-7.5, and the mol ratio that makes urea and formaldehyde is 1: 1.4-1.7, and adding consumption was the trimeric cyanamide of urea total amount 3-20%, 90 ± 5 ℃ of reactions 20-30 minute;
7) cool to 70 ± 5 ℃, add the 4th batch of urea, the mol ratio that makes urea and formaldehyde is 1: 1.2-1.4 is incubated 25-35 minute;
8) add ammoniacal liquor,, cool to below 40 ℃ discharging 60 ℃ of insulations 10-20 minute.
Wherein, the concentration of formaldehyde is 37%; The acid that activation formaldehyde uses is selected from one or more in sulfuric acid, hydrochloric acid, phosphoric acid, the formic acid; The concentration of ammoniacal liquor is 25%, and consumption is the 5-7% of urea total amount, is preferably 6%; The consumption of trimeric cyanamide is preferably 10% of urea total amount;
Particularly, the present invention is preferred:
In described step 2) in, the mol ratio that makes described urea and formaldehyde is 1: 3.03;
In described step 3), the mol ratio that makes described urea and formaldehyde is 1: 2.01;
In described step 6), the mol ratio that makes described urea and formaldehyde is 1: 1.6;
In described step 7), the mol ratio that makes urea and formaldehyde is 1: 1.4;
The advantage of the inventive method is:
1, by the manufacturing process of improving urea-formaldehyde resin and the trimeric cyanamide that adds urea total amount 3-20%, improved the resistance to boiling water that glueds joint goods;
2, the inventive method is by the activation of formaldehyde and the processing of last ammoniacal liquor, because formaldehyde activates under acidic conditions and becomes
+C
2OH has improved and amino reactive activity; The processing of last ammoniacal liquor makes most of free formaldehyde reaction generate hexamethylenetetramine, and therefore, the free formaldehyde content of the inventive method synthetic modified urea-formaldehyde resin is below 0.2%;
3, the inventive method is not dewatered, so manufacturing process is simple, and cost is low.
Embodiment
Describe the present invention in detail below by embodiment.
Embodiment one
Composition of raw materials:
Raw material | Mol ratio | Content (%) | Weight part | Remarks |
Urea formadehyde ammoniacal liquor melamine formic acid NaOH | 1.4 1 | 37 100 25 100 30 30 | 113.6 100 6 10 is an amount of | U1=27.7 part U2=14.1 part U3=10.7 part U4=surplus is regulated the pH value and is regulated the pH value |
Concrete reactions steps is as follows:
1) 37% industrial formol being added reactor, is 3.2-3.4 with the formic acid adjust pH;
2) be heated to 50 ℃, make formaldehyde activation 20 minutes, add first urea U127.7 weight part then, 50 ℃ of reactions 20 minutes;
3) transfer pH=7.2-7.8 with sodium hydroxide, add second batch of urea U214.1 weight part;
4) in 30-40 minute, be warming up to 90 ℃, be incubated 60 minutes;
5) with the formic acid adjust pH to 4.2-4.8, react to viscosity: 25 ℃, be coated with-4 glasss of 22-26 seconds;
6) use the sodium hydroxide adjust pH to 7.0-7.5, add the 3rd urea U310.7 weight part, adding consumption is the trimeric cyanamide of urea total amount 10%, and 90 ℃ were reacted 20 minutes;
7) cool to 70 ℃, add the 4th crowd of residual content urea U4, reacted 30 minutes;
8) adding concentration is 25% industrial ammonia, and the consumption of ammoniacal liquor is 6%, 60 ℃ of insulation 20 minutes of urea total amount, cools to 40 ℃, discharging.
The resin quality index:
Solids content 50-56%
PH value 8.0-8.5
Viscosity (20 ℃) 150-300mPas
Curing speed 80-100s
Free formaldehyde content<0.2%
Working life>4 hour
30-60 days storage period
Comparative example one
Proportioning raw materials:
Raw material | Mol ratio | Content % | Weight part | Remarks |
Urea formadehyde formic acid sodium hydroxide | 1.4 1 | 37 30 30 | 113.6 100 is an amount of | U1=41.8 part U2=10.7 part U3=residual content is regulated pH value and is regulated pH value |
Concrete reactions steps is as follows:
1) 37% industrial formol is added reactor, transfer pH=7.2-7.8 with sodium hydroxide;
2) add first urea U1 41.8 weight parts, be warming up to 90 ℃ in 30-40 minute, be incubated 60 minutes;
3) with the formic acid adjust pH to 4.2-4.8, react to viscosity: 25 ℃, be coated with-4 glasss of 22-26 seconds;
4) use the sodium hydroxide adjust pH to 7.0-7.5, add second batch of urea U2 10.7 weight part, 90 ℃ were reacted 20 minutes;
5) cool to 70 ℃, add the 3rd crowd of residual content urea U3, reacted 30 minutes;
6) cool to 40 ℃, discharging.
The resin quality index:
Solids content 50-56%
PH value 7.0-7.5
Viscosity (20 ℃) 150-300mPas
Curing speed 80-100 second
Free formaldehyde content<0.6%
Working life>4 hour
20-30 days storage period
Experimental example one
Utilize the cyanurotriamide modified urea resin tackiness agent of the embodiment of the invention one method acquisition and the urea-formaldehyde resin adhesive of comparative example one method acquisition to produce nine layers of glued board test specimen 1 and 2 respectively.Wherein, add the flour of cyanurotriamide modified urea resin weight 10% and 0.5% ammonium chloride during gluing; Veneer is 10 years living board using poplar boards; Heat pressing process is: pressure 1.0-1.5MPa, temperature: 105-115 ℃; Time: 40s/mm.
With the burst size of methanal of moisture eliminator method mensuration test specimen 1,2, the regulation of pressing GB/T17657-1999 " Test methods of evaluating the properties of woodbased panels and surface decorated woodbased panels " is measured the anti-boiling water bonding strength of test specimen 1,2, and its burst size of methanal and bonding strength see Table 1.
Table 1
Test specimen | Burst size of methanal (mg/L) | Bonding strength (MPa) |
Embodiment one test specimen 1 | Comparative example one test specimen 2 | Embodiment one test specimen 1 | Comparative example one test specimen 2 |
Nine plywood | 2.36 | 8.2 | 0.78 | 0.32 |
By table 1 as seen, the cyanurotriamide modified urea resin tackiness agent that utilizes the inventive method to produce is made multiplying plywood, the bonding strength of product can satisfy 1 level plywood national standard (being not less than 0.7MPa), and burst size of methanal can satisfy national E2 level (being not more than 5mg/L) standard.
Experimental example two
Adopt common urea-formaldehyde resin (mol ratio is 1: 1.3, solids content 56%) to produce nine layers of glued board test specimen 3 by above-mentioned same glued board processing method.
The resol (alkaline water soluble phenol resin, mol ratio are 1: 2.1, solids content 42%) that adopts factory to use is produced nine layers of glued board test specimen 4 by hot-press method; Wherein, the flour that adds weight resin 10% during gluing; Veneer is 10 years living board using poplar boards; Heat pressing process is: pressure 1.5-1.8MPa, temperature: 125-135 ℃; Time: 70s/mm.
Test specimen 1,2,3 and 4 is used separately as cement formwork, and its practical effect is as shown in table 2:
Table 2
Test specimen | Access times (inferior) |
Embodiment one test specimen 1 | Comparative example one test specimen 2 | Common urea-formaldehyde resin test specimen 3 | Resol test specimen 4 |
As cement formwork | 20 | 6 | 3 | 22 |
Practical application experiment shows, the multiplying plywood that cyanurotriamide modified urea resin tackiness agent of the present invention is produced is during as cement formwork, and its access times increase substantially, and can reach 20 times, glued joint the performance of goods near resol.