CN108823339B - Preparation method of environment-friendly modified aldehyde product - Google Patents
Preparation method of environment-friendly modified aldehyde product Download PDFInfo
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- CN108823339B CN108823339B CN201810685271.3A CN201810685271A CN108823339B CN 108823339 B CN108823339 B CN 108823339B CN 201810685271 A CN201810685271 A CN 201810685271A CN 108823339 B CN108823339 B CN 108823339B
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- C—CHEMISTRY; METALLURGY
- C14—SKINS; HIDES; PELTS; LEATHER
- C14C—CHEMICAL TREATMENT OF HIDES, SKINS OR LEATHER, e.g. TANNING, IMPREGNATING, FINISHING; APPARATUS THEREFOR; COMPOSITIONS FOR TANNING
- C14C3/00—Tanning; Compositions for tanning
- C14C3/02—Chemical tanning
- C14C3/08—Chemical tanning by organic agents
- C14C3/16—Chemical tanning by organic agents using aliphatic aldehydes
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Abstract
The invention discloses a preparation method of an environment-friendly modified aldehyde product, and belongs to the technical field of modified aldehydes. The method comprises the following steps: (1) stirring and mixing 3000-3500 parts by weight of formaldehyde solution, 800-1100 parts by weight of glutaraldehyde solution and 0-600 parts by weight of water, and heating to 70-80 ℃ until the temperature is raised; (2) adding 400-600 parts by weight of alkali liquor into the reaction solution, and reacting for 20-45 minutes at 90-98 ℃ after the addition is finished; (3) after the reaction is finished, carrying out reduced pressure distillation to 2/5-3/5 volume, adding 1200-1600 parts by weight of alkali liquor, reacting for 20-45 minutes at 90-98 ℃ after the addition is finished, and carrying out reduced pressure distillation after the reaction is finished; (4) and (4) repeating the step (3) for 3-5 times, stopping distillation until the formaldehyde content in the reaction liquid meets the preset requirement to obtain a product, and adding 40-80 parts by weight of sodium oxalate solution before the last two times of distillation.
Description
Technical Field
The invention belongs to the technical field of modified aldehyde, and particularly relates to a preparation method of an environment-friendly modified aldehyde product, in particular to a preparation method of a modified glutaraldehyde leather tanning agent with low formaldehyde release.
Background
Glutaraldehyde, an aliphatic aldehyde containing two very reactive aldehyde groups, was developed on the basis of the dialdehyde-resin tanning method, is favored by people at home and abroad as an excellent tanning agent, and was used in industry for a long time. It is characterized in that: (1) the speed of glutaraldehyde absorption by the pelts and the binding capacity are relatively outstanding; (2) the glutaraldehyde aqueous solution for tanning can not generate self-polymerization, so that the phenomenon that the grain surface of the leather is resinified and becomes hard and brittle can not be caused; (3) the glutaraldehyde leather has the advantages of water washing resistance, sweat resistance and alkali resistance, and the leather tanned by the glutaraldehyde leather is better than that tanned by formaldehyde alone. Glutaraldehyde, while having many advantages, has its disadvantages, as follows:
(1) the product has pungent smell and poor experience in processing field;
(2) has strong irritation to eyes, skin and mucosa, and is harmful to human body;
(3) easy to discolor and yellow at high temperature;
(4) the finished product tanned by the glutaraldehyde has yellow color, so the application of the finished product tanned by the glutaraldehyde in the fields of light-colored leather or white leather and the like is limited;
(5) the price is expensive;
(6) higher pH values are required for tanning, e.g. 6.5-8.0 for good performance, under which conditions chrome tanning is not effective.
Glutaraldehyde is modified in the prior art by a variety of means, such as fatty amines, amides, hydrocarbon ammonia, hydrazine and other aldehydes. The product after reaction is a mixture of reactants, unreacted raw materials and side reaction products, and the product is used as a leather tanning agent without strict separation, so that the functions of the product are diversified. The reaction speed of the modified glutaraldehyde and the leather blank is slowed, the action is milder, and the glutaraldehyde can penetrate into the inner channel of the chrome leather. In particular, in the prior art, glutaraldehyde can be modified by formaldehyde to obtain the leather tanning agent. However, it has the following problems:
(1) the formaldehyde and the glutaraldehyde can not be completely reacted, the formaldehyde is difficult to be completely distilled and removed from water, more than 5% of formaldehyde (trace glutaraldehyde is also remained) generally remains, the formaldehyde has a strong formaldehyde taste, the leather making experience is poor, and the physical and psychological health of workers can be affected;
(2) the free formaldehyde content of the leather tanned by the conventional formaldehyde-modified glutaraldehyde is usually more than 100ppm, and the European standard requirement is difficult to achieve (the free formaldehyde content of the adult contact leather is less than 20 ppm);
(3) the tanning time is slow, generally 4 to 12 hours;
(4) although the stability is improved to some extent compared with glutaraldehyde, the yellow pigment also turns yellow after being left for a long time.
Disclosure of Invention
In order to solve the problems, the invention provides a preparation method of an environment-friendly modified aldehyde product, which ensures that the formaldehyde is seriously excessive so that the molar ratio of the formaldehyde to the glutaraldehyde reaches 8-11:1 (the theoretical maximum value is 4: 1), and because the formaldehyde is excessively large, a leather tanning agent with specific component combination and concentration is obtained by a specific condition control and distillation mode, and has the advantages of good tanning effect, high stability, direct use and the like. The technical scheme is as follows:
the embodiment of the invention provides a preparation method of an environment-friendly modified aldehyde product, which comprises the following steps:
(1) 3000-3500 parts of formaldehyde solution, 800-1100 parts of glutaraldehyde solution and 0-600 parts of water (the formaldehyde content in the reaction system is about 23-27 wt%) are stirred, mixed and heated (about 1 hour) until the temperature is raised to 70-80 ℃.
(2) Adding 400-600 parts by weight of alkali liquor into the reaction liquid (the adding time is controlled to be about 3 hours), and reacting for 20-45 minutes (preferably 30 minutes) at the temperature of 90-98 ℃ after the adding is finished.
(3) After the reaction is finished, concentrating the reaction solution by reduced pressure distillation until the volume of the reaction solution is 2/5-3/5 (preferably 1/2, the subsequent distillation is calculated by the reaction solution after the reaction in the step (2), generally distilling to 2500 parts by weight, adding 1600 parts by weight of alkali liquor 1200-1600 parts by weight, reacting for 20-45 minutes (preferably 30 minutes) at 90-98 ℃ after the addition is finished, and distilling under reduced pressure after the reaction is finished.
(4) And (3) repeating the step (3) for 3-5 times (wherein the step (3) is used for the first distillation), sampling the reaction liquid and tracking until the content of formaldehyde in the reaction liquid meets the preset requirement during the last distillation, and stopping distillation to obtain the product. The dosage of the alkali liquor is gradually reduced along with the distillation times, 40-80 parts of sodium oxalate solution is added before the last two times of distillation, and the dosage of the sodium oxalate solution is gradually increased along with the distillation times.
Wherein the concentration of the formaldehyde solution is 30-40wt%, the concentration of the glutaraldehyde solution is 40-55wt%, the alkali liquor is 5-6 wt% of sodium hydroxide solution, and the concentration of the sodium oxalate solution is 2-4 wt%.
Wherein, the alkali liquor has the following functions: 1. as a catalyst to promote the aldolization reaction; 2. removing formaldehyde; 3. the pH value of the product is adjusted to meet the tanning requirement so that the product can be directly used.
Wherein, the sodium oxalate has the following functions: 1. removing formaldehyde; 2. the modified glutaraldehyde is stable and does not change color; 3. the pH value of the product is adjusted to meet the tanning requirement so that the product can be directly used; 4. the tanning effect is improved by taking the tanning agent as an auxiliary agent; 5. as a buffer, the pH of the product is lowered.
Among them, the steps (1) to (4) in the present example are preferably performed under vacuum. The vacuum distillation process in this embodiment is substantially the same as the conventional conditions of vacuum degree, temperature, etc. for synthesizing modified glutaraldehyde, so detailed descriptions of the present invention are omitted.
Wherein, the step (2) of the invention specifically comprises the following steps: adding alkali liquor into the reaction solution at the speed of 120-130 weight parts/h to slowly raise the temperature by 3-5 ℃, then increasing the addition speed to 170-180 weight parts/h to quickly raise the temperature to 84-88 ℃, stopping adding the alkali liquor (and starting jacket water cooling circulation) until the temperature is stabilized at 90-98 ℃, then adding the alkali liquor at the speed of 150-170 weight parts/h, wherein the total addition of the alkali liquor is 400-600 weight parts, and carrying out heat preservation reaction for 20-45 minutes after the alkali liquor is added. In the step, through the control of the flow and the reaction temperature, not only can the reaction process be controlled, but also the control of heat can be realized, and the volatilization of formaldehyde can be reduced.
Wherein, the step (3) of the invention specifically comprises the following steps: when the volume is 2/5-3/5 after the reaction is finished, 1200-1600 parts (usually 1550-1600 parts) alkali liquor is added, the adding speed is 150-170 parts/h, the adding temperature is 90-98 ℃, the heat preservation reaction is carried out for 20-45 minutes after the alkali liquor is added, and the reduced pressure distillation is carried out after the reaction is finished.
Wherein, the step (4) of the invention specifically comprises the following steps: repeating the step (3) for 4 times, and stopping distillation until the formaldehyde content in the reaction solution meets the preset requirement to obtain a product; during the first distillation, the using amount of the alkali liquor is 1550-; during the second distillation, the dosage of the alkali liquor is 1450 and 1500 weight parts; in the third distillation, the dosage of the alkali liquor is 1350-1400 weight parts, and the dosage of the sodium oxalate solution is 40-55 weight parts; in the fourth distillation, the dosage of the alkali liquor is 1200-1300 parts by weight, and the dosage of the sodium oxalate solution is 60-80 parts by weight. The feed rate was 150-.
In the steps (3) and (4), by adopting a special distillation method, not only can the reaction be fully carried out, but also the formaldehyde can be basically distilled out (less than 3wt percent), and the rest formaldehyde exists in a non-free form, so that the obtained product is odorless, the formaldehyde content in the tanned leather is lower than 20ppm (a pentosan method can be adopted in particular), and meanwhile, the stability of the product is improved.
Specifically, in step (4), the predetermined requirement is that the aldehyde (including formaldehyde, glutaraldehyde and other by-product aldehydes) content be less than 4 wt%.
Specifically, the concentration of the formaldehyde solution of the present invention is 37wt%, and the concentration of the glutaraldehyde solution is 50 wt%.
Preferably, the method provided by the invention comprises the following steps:
(1) 3000-3500 parts by weight of 37wt% formaldehyde solution, 800-1100 parts by weight of 50wt% glutaraldehyde solution and 400-600 parts by weight of water are stirred, mixed and heated to 70-80 ℃ and then stopped heating.
(2) Adding alkali liquor into the reaction liquid at the speed of 120-130 weight parts/h to slowly raise the temperature by 3-5 ℃, then increasing the addition speed to 170-180 weight parts/h to quickly raise the temperature to 84-88 ℃, stopping adding the alkali liquor until the temperature is stabilized at 90-98 ℃, then adding the alkali liquor at the speed of 150-170 weight parts/h, wherein the total addition of the alkali liquor is 400-600 weight parts, and carrying out heat preservation reaction for 20-45 minutes after the alkali liquor is added.
(3) And after the reaction is finished, carrying out reduced pressure distillation and concentration to 1/2 volume, adding 1550-. Step (3) is used as the first distillation.
(4) Repeating the step (3) for 3 times, and stopping distillation when the aldehyde content in the reaction solution is less than 4wt% in the last distillation to obtain a product; wherein, the dosage of the alkali liquor is 1550-; during the second distillation, the dosage of the alkali liquor is 1450 and 1500 weight parts; in the third distillation, the dosage of the alkali liquor is 1350-1400 weight parts, and the dosage of the sodium oxalate solution is 40-55 weight parts; in the fourth distillation, the dosage of the alkali liquor is 1200-1300 parts by weight, and the dosage of the sodium oxalate solution is 60-80 parts by weight.
The modified aldehyde obtained by the method provided by the invention has the following advantages:
1. the obtained product has low formaldehyde content and basically no formaldehyde odor, so the formaldehyde release amount is low in the leather tanning process, and the experience is good;
2. the free formaldehyde content in the leather tanned by the tanning agent is less than 20ppm, the leather meets most standards, and the product competitiveness is stronger;
3. the retanning time is reduced, and only 1.5-2.5 hours are needed generally;
4. the product performance can be improved, the product is soft, and the shrinkage temperature is higher;
5. the product is not easy to change color, and is convenient to store and transport;
6. the product can be directly used without adjusting pH value during tanning.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below.
Example 1:
example 1 discloses a method for preparing an environmentally-friendly modified aldehyde product, comprising:
1. starting a vacuum system, vacuumizing the reaction kettle, adding about 3300Kg of 37wt% formaldehyde, starting a stirring paddle, continuously adding about 900Kg of 50wt% glutaraldehyde, continuously adding 500Kg of water, and starting steam for heating. 2. After about 1 hour, heating the reaction kettle to 80 ℃, and stopping steam; slowly adding the prepared sodium hydroxide solution (5.5wt ‰) into the reaction kettle, controlling the flow at 125kg/h, slowly increasing the temperature, adjusting the temperature of alkali liquor to 175kg/h, rapidly increasing the temperature to 86 deg.C, and suspending adding alkali liquor. The temperature is continuously and rapidly increased to 94 ℃, the jacket is opened for circulating cooling water cooling, the temperature is gradually reduced after the temperature is increased to 98 ℃, the alkali liquor is continuously added after the temperature is reduced to 94 ℃, the flow is adjusted to about 150-. 3. And (3) reacting for 30 minutes after the first alkali liquor is added, adding 170kg/h alkali liquor under a vacuum condition according to the flow rate of 150-.
4. After the first distillation is finished, adding alkaline liquor according to the flow rate of 145-165kg/h under the vacuum condition, wherein 1475kg is total, the temperature is basically constant at 94 ℃, after the alkaline liquor is added, keeping the temperature for reaction for 30 minutes, starting steam for heating distillation, and stopping the distillation until about half of the volume of the reaction liquid in the step 2 to realize the second distillation.
5. And after the second distillation is finished, adding 160kg/h of alkali liquor according to the flow rate of 140-.
6. And after the third distillation is finished, adding alkali liquor according to the flow rate of 135-one-time addition of 150kg/h under the vacuum condition, wherein the total amount is 1250kg, the temperature is basically constant at 94 ℃, simultaneously adding 70kg of sodium oxalate solution, after the alkali liquor is added, carrying out heat preservation reaction for 30 minutes, starting steam for heating distillation, sampling the reaction liquid at regular time during distillation, and stopping obtaining a product when the content of aldehyde (specifically, the content of formaldehyde is less than 3.5 wt%) in the reaction liquid is less than 4wt%, namely the fourth distillation.
The obtained product is as follows: the density is 1.079g/ml, the pH is 7.4, the color number is about 60, the formaldehyde odor is basically not generated, and the aldehyde content is 3.7 percent.
Verification example
The method comprises the following steps of processing the cowhide, wherein the processing comprises the steps of wet blue hide manufacturing, washing, squeezing, retanning, neutralizing, dyeing, fatliquoring, fixing color and the like, wherein the procedures of wet blue hide manufacturing (chrome tanning agent), washing, squeezing, neutralizing, dyeing, fatliquoring, fixing color and the like are the same as those of the existing leather manufacturing process.
Experimental example, the retanning process was: in a rotating drum, water is added in an amount of 1.2 times the weight of leather, the amount of the leather tanning agent provided in example 1 is 4% (by weight), the pH value is 7.0-7.5, the temperature is 40-45 ℃, and the tanning time is 1.5-2.5 hours.
Treatment 1, the retanning process is as follows: in a rotary drum, water with the weight 1.2 times of that of the leather and 4 percent of glutaraldehyde tanning agent (weight) are added, the pH value is adjusted to 7.0-7.5 (alkali is usually added to adjust the pH value), the temperature is 40-45 ℃, and the tanning time is 4-6 hours.
And 2, the retanning process comprises the following steps: in a rotary drum, water with the weight 1.2 times of that of leather is added, a commercial formaldehyde modified glutaraldehyde tanning agent (Wuhan organic synthesis chemical plant) with the weight of 4 percent and the pH value of 7.0-7.5 (alkali is usually added to adjust the pH value) is added, the temperature is 40-45 ℃, and the tanning time is 1.5-2.5 hours.
And (3) treating the mixture, wherein the retanning process comprises the following steps: in a rotary drum, water with the weight 1.2 times of that of leather is added, a commercial formaldehyde modified glutaraldehyde tanning agent (Wuhan organic synthesis chemical factory) with the weight of 4 percent and the pH value of 7.0-7.5 (alkali is usually added to adjust the pH value) is added, the temperature is 40-45 ℃, and the tanning time is 4-6 hours.
And 4, the retanning process comprises the following steps: in a rotary drum, water with the weight 1.2 times of that of leather is added, the synthetic formaldehyde modified glutaraldehyde tanning agent I4% (by weight) has the pH value of 7.0-7.5 (adjusted by adding sodium hydroxide), the temperature is 40-45 ℃, and the tanning time is 1.5-2.5 hours. The preparation method of the synthetic formaldehyde modified glutaraldehyde tanning agent I comprises the following steps:
the raw materials are as follows: 3300Kg of formaldehyde with the weight percent of 37, 900Kg of glutaraldehyde with the weight percent of 50, 500Kg of water and 500Kg of alkali liquor, the reaction temperature is 90-98 ℃, and the formaldehyde is removed once by a conventional distillation method (without adding sodium oxalate solution).
And (5) treating the leather, wherein the retanning process comprises the following steps: in a rotary drum, water with the weight 1.2 times of that of leather is added, and synthetic formaldehyde modified glutaraldehyde tanning agent II4% (by weight) has the pH value of 7.0-7.5, the temperature of 40-45 ℃ and the tanning time of 1.5-2.5 hours. The preparation method of the synthetic formaldehyde modified glutaraldehyde tanning agent II comprises the following steps:
the raw materials are as follows: 2000Kg of formaldehyde with a concentration of 37% by weight, 900Kg of glutaraldehyde with a concentration of 50% by weight, 1000Kg of water and 500Kg of lye, at a reaction temperature of 90-98 ℃ and by distillation in the same manner as in example 1 (without addition of the sodium oxalate solution).
And 6, the retanning process comprises the following steps: in a rotary drum, water with the weight 1.2 times of that of the leather is added, and the synthetic formaldehyde modified glutaraldehyde tanning agent III4% (by weight) has the pH value of 7.0-7.5, the temperature of 40-45 ℃ and the tanning time of 1.5-2.5 hours. The preparation method of the synthetic formaldehyde modified glutaraldehyde tanning agent III comprises the following steps:
the preparation method is the same as example 1, except that: no sodium oxalate solution was added.
And 7, the retanning process comprises the following steps: in a rotary drum, water with the weight 1.2 times of that of the leather is added, and the synthetic formaldehyde modified glutaraldehyde tanning agent IV4% (by weight) has the pH value of 7.0-7.5, the temperature of 40-45 ℃ and the tanning time of 1.5-2.5 hours. The preparation method of the synthetic formaldehyde modified glutaraldehyde tanning agent IV comprises the following steps:
the preparation method is the same as example 1, except that: no sodium oxalate solution was added before distillation, whereas after 4 distillations were completed, an equal amount of sodium oxalate solid was added.
The results are as follows:
TABLE 1
| Treatment of | Shrinkage temperature (. degree.C.) | Free formaldehyde in leather (ppm) |
| The tanning agent of the invention | 95.1 | 13 |
| Process 1 | 83.5 | 5 |
| Treatment 2 | 84.3 | 53 |
| Treatment 3 | 87.8 | 77 |
| Treatment 4 | 91.4 | 89 |
| Treatment 5 | 88.2 | 10 |
| Treatment 6 | 92.3 | 27 |
| Treatment 7 | 92.3 | 25 |
As can be seen from the data in Table 1, the tanning agent provided by the invention can obviously improve the shrinkage temperature and reduce the formaldehyde content, and compared with the conventional modified glutaraldehyde, the tanning agent comprehensively considers the requirements of tanning effect and formaldehyde release amount, so that the tanned leather has higher competitiveness.
TABLE 2
| Detecting items | The tanning agent of the invention | Process 1 | Treatment 3 |
| Tear Strength (N/mm) | 63.2 | 65.3 | 64.5 |
| Elongation at Break (%) | 50.1 | 53.7 | 52.3 |
| Softness (mm) | 6.5 | 5.1 | 5.5 |
As can be seen from the data in table 2, the tannage treated leather provided by the invention meets the national standards and has better softness than the conventional glutaraldehyde and modified glutaraldehyde.
TABLE 3
| 15 days | 30 days | 45 days | 60 days | 90 days | 120 days | 150 days | |
| Example 1 | No color change | No color change | No color change | No color change | No color change | No color change | No color change |
| Tanning agent I | No color change | No color change | No color change | No color change | No color change | Color change | |
| Tanning agent II | No color change | No color change | No color change | Color change | |||
| Tanning agent III | No color change | No color change | No color change | No color change | No color change | Color change | |
| Tanning agent IV | No color change | No color change | No color change | No color change | No color change | No color change | Color change |
| Glutaraldehyde | No color change | Color change |
Table 3 shows the discoloration upon standing of the tanning agent treated in the range of 4 to 7, the tanning agent obtained in example 1 and 50% by weight of glutaraldehyde in a 20ml flask sealed (15 ml of the test solution, air as the rest), placed in an incubator at 25 ℃ and visually observed (based on the apparent discoloration) for the time indicated in the table. The tanning agent provided in experimental example 1 still showed no significant discoloration at 200 days. As can be seen from table 3, the product provided by the present invention is more stable.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.
Claims (3)
1. A method for preparing an environment-friendly modified aldehyde product, which is characterized by comprising the following steps:
(1) stirring and mixing 3000-3500 parts by weight of formaldehyde solution, 800-1100 parts by weight of glutaraldehyde solution and 0-600 parts by weight of water, and heating to 70-80 ℃ until the temperature is raised;
(2) adding alkali liquor into the reaction liquid at the speed of 120-130 weight parts/h to slowly raise the temperature by 3-5 ℃, then raising the addition speed to 170-180 weight parts/h to quickly raise the temperature to 84-88 ℃, stopping adding the alkali liquor until the temperature is stabilized at 90-98 ℃, then adding the alkali liquor at the speed of 150-170 weight parts/h, wherein the total addition of the alkali liquor is 400-600 weight parts, and carrying out heat preservation reaction for 20-45 minutes after the alkali liquor is added;
(3) after the reaction is finished, carrying out reduced pressure distillation to 2/5-3/5 volume, adding 1600 parts by weight of alkali liquor at the speed of 150-170 parts by weight/h, keeping the temperature for 20-45 minutes after the alkali liquor is added, and carrying out reduced pressure distillation after the reaction is finished;
(4) repeating the step (3) for 4 times, and stopping distillation until the formaldehyde content in the reaction solution meets the preset requirement to obtain a product; during the first distillation, the using amount of the alkali liquor is 1550-; during the second distillation, the dosage of the alkali liquor is 1450 and 1500 portions; in the third distillation, the dosage of the alkali liquor is 1350-1400 parts, and the dosage of the sodium oxalate solution is 40-55 parts; in the fourth distillation, the use amount of the alkali liquor is 1200-1300 parts, the use amount of the sodium oxalate solution is 60-80 parts, and the preset requirement is that the aldehyde content is less than 4 wt%;
the formaldehyde solution is 30-40wt%, the glutaraldehyde solution is 40-55wt%, the alkali liquor is 5-6 wt% of sodium hydroxide solution, and the sodium oxalate solution is 2-4 wt%.
2. The method for preparing the environment-friendly modified aldehyde product according to claim 1, wherein the concentration of the formaldehyde solution is 37wt%, and the concentration of the glutaraldehyde solution is 50 wt%.
3. The method for preparing the environment-friendly modified aldehyde product according to claim 1, wherein the method comprises the following steps:
(1) 3000-3500 parts by weight of 37wt% formaldehyde solution, 800-1100 parts by weight of 50wt% glutaraldehyde solution and 400-600 parts by weight of water are stirred, mixed and heated to 70-80 ℃ and then stopped heating;
(2) adding alkali liquor into the reaction liquid at the speed of 120-130 weight parts/h to slowly raise the temperature by 3-5 ℃, then raising the addition speed to 170-180 weight parts/h to quickly raise the temperature to 84-88 ℃, stopping adding the alkali liquor until the temperature is stabilized at 90-98 ℃, then adding the alkali liquor at the speed of 150-170 weight parts/h, wherein the total addition of the alkali liquor is 400-600 weight parts, and carrying out heat preservation reaction for 20-45 minutes after the alkali liquor is added;
(3) when the volume is reduced and distilled to 1/2 after the reaction is finished, 1550-;
(4) repeating the step (3) for 4 times, and stopping distillation until the aldehyde content in the reaction solution is less than 4wt% to obtain a product; wherein, the dosage of the alkali liquor is 1550-; during the second distillation, the dosage of the alkali liquor is 1450 and 1500 portions; in the third distillation, the dosage of the alkali liquor is 1350-1400 parts, and the dosage of the sodium oxalate solution is 40-55 parts; in the fourth distillation, the dosage of the alkali liquor is 1200-1300 parts, and the dosage of the sodium oxalate solution is 60-80 parts.
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1121084A (en) * | 1994-10-21 | 1996-04-24 | 遵化市钟馗实业公司 | Low-poison synthetic urea-formaldehyde resin glue and its production method |
| CN101875754A (en) * | 2009-10-30 | 2010-11-03 | 中国林业科学研究院木材工业研究所 | Environmental-friendly type dextrin modified phenolic resin and preparation method thereof |
| CN103451026A (en) * | 2013-09-13 | 2013-12-18 | 北京泛博化学股份有限公司 | Modified glutaraldehyde tanning agent and preparation method and applications thereof |
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1121084A (en) * | 1994-10-21 | 1996-04-24 | 遵化市钟馗实业公司 | Low-poison synthetic urea-formaldehyde resin glue and its production method |
| CN101875754A (en) * | 2009-10-30 | 2010-11-03 | 中国林业科学研究院木材工业研究所 | Environmental-friendly type dextrin modified phenolic resin and preparation method thereof |
| CN103451026A (en) * | 2013-09-13 | 2013-12-18 | 北京泛博化学股份有限公司 | Modified glutaraldehyde tanning agent and preparation method and applications thereof |
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