阅读说明：本技术 一种环保型无氯湿强剂及其制备方法 (Environment-friendly chlorine-free wet strength agent and preparation method thereof ) 是由 俞晗 梁福根 钱进 来雷 张勇 谢占豪 肖鹏 姚胜 陈文杰 钟俊汉 于 2020-12-21 设计创作，主要内容包括：本发明公开了一种环保型无氯湿强剂及其制备方法。本发明采用的制备方法包括以下步骤：a、加成反应：聚乙烯亚胺和含多环氧基团的交联剂调节pH值后,在水相中进行加成反应,反应后得到聚乙烯亚胺-环氧树脂溶液；b、交联反应：聚乙烯亚胺-环氧树脂溶液在水相中进行交联反应,到达目标黏度后加入酸和水终止反应,反应后得到阳离子化聚乙烯亚胺-环氧树脂溶液,即环保型无氯湿强剂。本发明在不降低纸张湿强度的情况下,在制备时不产生AOX；采用的反应条件不需要高温,对设备的要求更低,可操作性更强。(The invention discloses an environment-friendly chlorine-free wet strength agent and a preparation method thereof. The preparation method adopted by the invention comprises the following steps: a. addition reaction: after the pH value of polyethyleneimine and a cross-linking agent containing multi-epoxy groups is adjusted, performing addition reaction in a water phase to obtain a polyethyleneimine-epoxy resin solution after reaction; b. and (3) crosslinking reaction: the polyethyleneimine-epoxy resin solution is subjected to a crosslinking reaction in a water phase, acid and water are added to stop the reaction after the target viscosity is reached, and the cationized polyethyleneimine-epoxy resin solution, namely the environment-friendly chlorine-free wet strength agent, is obtained after the reaction. The invention does not generate AOX during the preparation under the condition of not reducing the wet strength of the paper; the adopted reaction condition does not need high temperature, the requirement on equipment is lower, and the operability is stronger.)

1. The preparation method of the environment-friendly chlorine-free wet strength agent is characterized by comprising the following steps:

a. addition reaction: after the pH value of polyethyleneimine and a cross-linking agent containing multi-epoxy groups is adjusted, performing addition reaction in a water phase to obtain a polyethyleneimine-epoxy resin solution after reaction;

b. and (3) crosslinking reaction: the polyethyleneimine-epoxy resin solution is subjected to a crosslinking reaction in a water phase, acid and water are added to stop the reaction after the target viscosity is reached, and the cationized polyethyleneimine-epoxy resin solution, namely the environment-friendly chlorine-free wet strength agent, is obtained after the reaction.

2. The method for preparing the environment-friendly chlorine-free wet strength agent as claimed in claim 1, wherein in the step a, the pH value is adjusted to 7-9.

3. The method for preparing the environment-friendly chlorine-free wet strength agent as claimed in claim 1, wherein in the step a, the reaction temperature is 5-15 ℃ and the addition reaction time is 1.5-5 h.

4. The method as claimed in claim 1, wherein in step a, the polyethyleneimine is one or more of 300-100000 molecular weight.

5. The method as claimed in claim 1, wherein in step a, the crosslinking agent containing polyepoxy groups is one or more of ethylene glycol diglycidyl ether, glycerol triglycidyl ether, trimethylolpropane triglycidyl ether, bisphenol a epoxy resin, and bisphenol a epoxy resin polyoxyethylene polyoxypropylene modifier.

6. The process of claim 1 or 5, wherein in step a, the molar ratio of the primary, secondary and tertiary amino groups of the polyethyleneimine to the epoxy groups of the polyepoxy-group-containing crosslinking agent is 0.95-1.05: 1.

7. the method for preparing the environment-friendly chlorine-free wet strength agent according to claim 1, wherein in the step b, the reaction temperature is 30-35 ℃, the target viscosity is 150cp s, and the acid is one or more of formic acid, acetic acid, hydrochloric acid, sulfuric acid and phosphoric acid.

8. The method for preparing the environment-friendly chlorine-free wet strength agent as claimed in claim 1, wherein in the step b, the acid and the water are added in a single step and are added in multiple times along with the increase of the viscosity; when the viscosity is increased for a plurality of times, the addition is carried out for three times when the viscosity is 50cp · s, 100cp · s and 150cp · s.

9. The method for preparing the environment-friendly chlorine-free wet strength agent as claimed in claim 1, wherein in the step b, the pH value is controlled to be 3-5 after termination.

10. An environment-friendly chlorine-free wet strength agent, characterized by being prepared by the preparation method of any one of claims 1 to 9.

Technical Field

The invention belongs to the field of chemical synthesis, and relates to a wet strength agent for paper, in particular to an environment-friendly chlorine-free wet strength agent and a preparation method thereof.

Background

Polyamide polyamine-epichlorohydrin resins have been widely used as wet strength agents for paper, and methods for their manufacture are well known. Generally, in the addition reaction of polyamide polyamine, low molecular weight organic halogen compounds (AOX) represented by 1, 3-dichloro-2-propanol (DCP) are produced. In recent years, AOX has received high attention as a harmful substance to human body, and there is a great demand for an AOX-free environment-friendly chlorine-free wet strength agent due to the requirements for environmental protection and human body protection.

Japanese patent JPA2011012128 discloses a chlorine-free wet strength agent and a preparation method thereof. In this method, a cationic thermosetting resin is obtained by reacting an aliphatic dicarboxylic acid with a polyalkyl polyamine to obtain a polyamide, adding an acid to the polyamide, and reacting the resultant polyamide with a diepoxy compound. However, the chlorine-free wet strength agent obtained by this method has a crosslinking reaction that is difficult to control, has a low cationization degree, has a poor retention effect on paper, and cannot exert a sufficient wet strength effect.

Chinese patent CN110172861A discloses a chlorine-free wet strength agent and a preparation method thereof. Firstly, adding a cationic monomer and a long-chain aliphatic vinyl monomer into a polyethylene polyamine liquid, adding epoxy resin for continuous reaction after reacting for a period of time, then adding a small amount of isocyanate tripolymer for multi-branched chain extension, adding deionized water for dispersion after the system reaches a certain viscosity, then dropwise adding a mixture of the epoxy resin and an ether solvent, adding deionized water after the system reaches a certain viscosity, and adjusting the pH value of the system to 3-4 to obtain the chlorine-free wet strength agent with waterproof and wet strength functions. However, the chlorine-free wet strength agent obtained by the method uses isocyanate trimer with strong toxicity in the reaction process, and the selected epoxy resin raw material has poor compatibility with water, the reaction degree is low, and the chlorine-free wet strength agent with high wet strength performance is difficult to obtain.

Chinese patent CN111073003A discloses an environment-friendly chlorine-free high-strength wet strength agent and a preparation method thereof. The product is prepared from diethylenetriamine, adipic acid, maleated rosin, deionized water, glyoxal and sodium sulfite, does not contain toxic substance organic chlorine, endows paper with good wet strength, improves paper dry strength and improves paper water resistance. However, the chlorine-free wet strength agent obtained by the method has short shelf life and is easy to gel during storage.

Disclosure of Invention

The technical problem to be solved by the invention is to overcome the defects in the prior art and provide an environment-friendly chlorine-free wet strength agent which can not generate AOX during preparation under the condition of not reducing the wet strength of paper and a preparation method thereof.

Therefore, the invention adopts the following technical scheme: the preparation method of the environment-friendly chlorine-free wet strength agent comprises the following steps:

a. addition reaction: after the pH value of polyethyleneimine and a cross-linking agent containing multi-epoxy groups is adjusted, performing addition reaction in a water phase to obtain a polyethyleneimine-epoxy resin solution after reaction;

b. and (3) crosslinking reaction: the polyethyleneimine-epoxy resin solution is subjected to a crosslinking reaction in a water phase, acid and water are added to stop the reaction after the target viscosity is reached, and the cationized polyethyleneimine-epoxy resin solution, namely the environment-friendly chlorine-free wet strength agent, is obtained after the reaction.

Further, in the step a, the pH value is adjusted to 7-9.

Further, in the step a, the reaction temperature is 5-15 ℃, and the addition reaction time is 1.5-5 h.

Further, in the step a, the polyethyleneimine is one or more of molecular weight 300-100000.

In the step a, the crosslinking agent containing a polyepoxy group is one or more of ethylene glycol diglycidyl ether, glycerol triglycidyl ether, trimethylolpropane triglycidyl ether, bisphenol a epoxy resin, and bisphenol a epoxy resin polyoxyethylene polyoxypropylene modified product.

The bisphenol A epoxy resin is E-55, E-51, E-44 and E-42, the bisphenol A epoxy resin polyoxyethylene polyoxypropylene modification is E-55 polyoxyethylene polyoxypropylene modification, E-51 polyoxyethylene polyoxypropylene modification, E-44 polyoxyethylene polyoxypropylene modification and E-42 polyoxyethylene polyoxypropylene modification, and preferably E-44, E-42, E-44 polyoxyethylene polyoxypropylene modification and E-42 polyoxyethylene polyoxypropylene modification. Too high an epoxy value is detrimental to reaction control and molecular weight enhancement of the finished product, and too low an epoxy value reduces the wet strength enhancement capability of the finished product.

The bisphenol A epoxy resin polyoxyethylene polyoxypropylene modified product is a polyoxyethylene polyoxypropylene emulsion of bisphenol A epoxy resin or a polyoxyethylene polyoxypropylene graft of bisphenol A epoxy resin.

Further, in the step a, the molar ratio of the primary, secondary and tertiary amino groups of the polyethyleneimine to the epoxy groups of the polyepoxy-group-containing crosslinking agent is 0.95-1.05: 1.

further, in the step b, the reaction temperature is 30-35 ℃, the target viscosity is 150cp · s, and the acid is one or more of formic acid, acetic acid, hydrochloric acid, sulfuric acid and phosphoric acid.

Further, in the step b, the adding method of the acid and the water comprises one-time adding and adding for a plurality of times along with the increase of the viscosity, preferably adding for a plurality of times along with the increase of the viscosity, and preferably adding for three times when the viscosity is 50cp · s, 100cp · s and 150cp · s.

Further, in the step b, the pH value after termination is controlled to be 3-5, preferably 4-4.5. When the pH value is more than 5, the storage shelf life is shortened, and when the pH value is less than 3, the viscosity of the finished product is reduced along with the time, and the wet strength is reduced.

The invention also provides the environment-friendly chlorine-free wet strength agent prepared by the preparation method.

The invention has the beneficial effects that:

1. the polyethyleneimine is used as a base material, and has stronger reactivity and shorter reaction time compared with polyamide polyamine base materials; has stronger cationic property, can be more effectively combined with fiber, and improves wet strength.

2. Ethylene glycol diglycidyl ether, glycerol triglycidyl ether, trimethylolpropane triglycidyl ether, bisphenol A epoxy resin and bisphenol A epoxy resin polyoxyethylene polyoxypropylene modified substances are used as cross-linking agents, and hydrophilic and lipophilic cross-linking agents containing polyepoxy groups are used, so that reaction activity is guaranteed, a certain water resistance can be brought to a finished product, and wet strength is further improved.

3. In the synthesis of polyamide polyamine-epichlorohydrin, amidation reaction generally needs high temperature of 140-160 ℃, crosslinking reaction also needs high temperature of 60-75 ℃, and the reaction condition adopted by the invention does not need high temperature, so that the requirement on equipment is lower, and the operability is stronger.

Detailed Description

The invention relates to a preparation method of an environment-friendly chlorine-free wet strength agent, which comprises the following steps:

a. addition reaction: after the pH value of polyethyleneimine and a cross-linking agent containing multi-epoxy groups is adjusted, performing addition reaction in a water phase to obtain a polyethyleneimine-epoxy resin solution after reaction;

b. and (3) crosslinking reaction: the polyethyleneimine-epoxy resin solution is subjected to a crosslinking reaction in a water phase, acid and water are added to stop the reaction after the target viscosity is reached, and the cationized polyethyleneimine-epoxy resin solution, namely the environment-friendly chlorine-free wet strength agent, is obtained after the reaction.

In the step a, the pH value is adjusted to be 7-9, the reaction temperature is 5-15 ℃, the addition reaction time is 1.5-5h, and the polyethyleneimine is one or more of molecular weight 300-100000. The molar ratio of the primary, secondary and tertiary amino groups of the polyethyleneimine to the epoxy groups of the polyepoxy-group-containing crosslinking agent is 0.95-1.05: 1.

the crosslinking agent containing the polyepoxy group is one or more of ethylene glycol diglycidyl ether, glycerol triglycidyl ether, trimethylolpropane triglycidyl ether, bisphenol A epoxy resin and bisphenol A epoxy resin polyoxyethylene polyoxypropylene modified substance. The bisphenol A epoxy resin is E-55, E-51, E-44 and E-42; the bisphenol A epoxy resin polyoxyethylene polyoxypropylene modified substance is an E-55 polyoxyethylene polyoxypropylene modified substance, an E-51 polyoxyethylene polyoxypropylene modified substance, an E-44 polyoxyethylene polyoxypropylene modified substance and an E-42 polyoxyethylene polyoxypropylene modified substance. The bisphenol A epoxy resin polyoxyethylene polyoxypropylene modified product is a polyoxyethylene polyoxypropylene emulsion of bisphenol A epoxy resin or a polyoxyethylene polyoxypropylene graft of bisphenol A epoxy resin.

In the step b, the reaction temperature is 30-35 ℃, the target viscosity is 150 cp.s, and the acid is one or more of formic acid, acetic acid, hydrochloric acid, sulfuric acid and phosphoric acid.

In the step b, the adding method of the acid and the water comprises one-time adding and adding for a plurality of times along with the increase of the viscosity, preferably adding for a plurality of times along with the increase of the viscosity, and preferably adding for three times when the viscosity is 50cp · s, 100cp · s and 150cp · s. After termination, the pH is controlled to 3-5, preferably 4-4.5.

The present invention is further illustrated by the following examples, which are not to be construed as limiting the invention in any way.

Example 1

a. Addition reaction

16.5g of SP-006 (molecular weight is 600, and total amino value is 20mmol/g), 5.0g of phosphoric acid and 50.0g of deionized water are added into a 500mL four-neck flask, the temperature of a cold water bath is controlled to be 5 ℃, 5.8g of E4465.0 g and 5.8g of ethylene glycol diglycidyl ether are respectively added into two dropping funnels, and simultaneously dropwise added, the temperature is controlled to be less than 15 ℃, and the temperature is kept for 3 hours.

b. Crosslinking reaction

Adding 100.0g of deionized water, heating to 30 ℃, and adding 2g of phosphoric acid when the viscosity is increased to 50cp s; continuing to keep the temperature, when the viscosity is increased to 100 cp.s, adding 2g of phosphoric acid and 130.0g of water, and continuing to keep the temperature; when the viscosity increased to 150cp · s, the addition of 2g of phosphoric acid was terminated. After the reaction is finished, the pH value is adjusted to 3.5, and the chlorine-free wet strength agent with the solid content of 25.31 percent and the viscosity of 170.5cp & s is obtained.

Example 2

In example 1, 16.5g of SP-006 was replaced with 17.5g of SP-018 (molecular weight 1800 and total amino value 19mmol/g), and the rest of the procedure was unchanged. The chlorine-free wet strength agent with the pH value of 3.4, the solid content of 24.92 percent and the viscosity of 156.7cp · s is obtained.

Example 3

In example 1, 16.5g of SP-006 was replaced with 18.5g P-1000 (molecular weight 70000, total amino value 18mmol/g), and the other operations were not changed. The chlorine-free wet strength agent with the pH value of 3.5, the solid content of 25.66 percent and the viscosity of 152.5cp · s is obtained.

Example 4

In example 1, 65.0g E44 and 5.8g of ethylene glycol diglycidyl ether were replaced with 56.7g E44 and 8.7g of ethylene glycol diglycidyl ether, and the other operations were unchanged. The obtained chlorine-free wet strength agent has pH of 3.5, solid content of 25.11% and viscosity of 180.3cp · s.

Example 5

In example 1, 65.0g E44 and 5.8g of ethylene glycol diglycidyl ether were replaced with 48.3g E44 and 11.6g of ethylene glycol diglycidyl ether, and the other operations were unchanged. The obtained chlorine-free wet strength agent has pH of 3.4, solid content of 25.05% and viscosity of 167.3cp · s.

Example 6

In example 1, 65.0g E44 was replaced with 68.1g E42, and the other operations were not changed. The obtained chlorine-free wet strength agent has pH of 3.4, solid content of 26.13% and viscosity of 170.2cp · s.

Example 7

In example 1, 5.8g of ethylene glycol diglycidyl ether was replaced with 5.8g of glycerol triglycidyl ether, and the rest of the procedure was unchanged. The obtained chlorine-free wet strength agent has pH of 3.3, solid content of 24.58% and viscosity of 150.7cp · s.

Example 8

In example 1, 5.8g of ethylene glycol diglycidyl ether was replaced with 6.7g of trimethylolpropane triglycidyl ether, and the rest of the procedure was unchanged. The obtained chlorine-free wet strength agent has pH of 3.0, solid content of 25.44% and viscosity of 180.5cp · s.

Example 9

In example 1, 65.0g E44 was replaced with 160.0g E44 polyoxyethylene polyoxypropylene emulsion (epoxy value 0.18, solid portion 50%), and the other operations were not changed. The chlorine-free wet strength agent with the pH value of 3.5, the solid content of 25.73 percent and the viscosity of 175.5cp & s is obtained.

Example 10

In example 1, 65.0g E44 and 5.8g of ethylene glycol diglycidyl ether were replaced with 29.1g of ethylene glycol diglycidyl ether, the addition of 2.0g of phosphoric acid before termination was replaced with the addition of 8.5g of phosphoric acid before termination, and the other operations were not changed. The obtained chlorine-free wet strength agent has pH of 3.5, solid content of 27.35% and viscosity of 160.5cp · s.

Example 11

In example 1, 65.0g E44 and 5.8g of ethylene glycol diglycidyl ether were replaced with 81.3g E44, and the rest of the procedure was unchanged. The chlorine-free wet strength agent with the pH value of 3.3, the solid content of 25.02 percent and the viscosity of 156.6cp · s is obtained.

Comparative example 1

The PAE type chlorine-containing wet strength agent with the pH value of 4.5, the solid content of 25.20 percent and the viscosity of 93.0 cp.s is synthesized by using the known synthesis method of PAE.

Comparative example 2

The PAE type chlorine-containing wet strength agent with the pH value of 4.3, the solid content of 25.12 percent and the viscosity of 89.7cp & s is synthesized by using the known synthesis method of PAE.

Wet strength agent application evaluation effect:

the present invention is not limited to the above-mentioned embodiments, and based on the technical solutions disclosed in the present invention, those skilled in the art can make some substitutions and modifications to some technical features without creative efforts according to the disclosed technical contents, and these substitutions and modifications are all within the protection scope of the present invention.