CN106589298A - Organosilicon-modified cationic aqueous polyurethane paper wet strength agent and preparation method - Google Patents

Abstract

The invention relates to the field of chemical technology, in particular to a silicone-modified cationic water-based polyurethane paper wet strength agent and a preparation method, comprising the following raw materials: polyether diol, tertiary amino polyether diol, polyether triol, dilauric acid Dibutyltin, isocyanate, cationic hydrophilic chain extender, capping agent, glacial acetic acid, acetone, silicone modifier, water. The present invention introduces both tertiary amino groups into the soft segment and hard segment structure of the molecule, forms quaternary ammonium salt cations after acid neutralization, increases the degree of cation, better adsorbs on negatively charged paper fibers, and can be quickly and completely retained Through organosilicon modification, the crosslinking density is improved to form a chemical network structure, which can be used on paper to form a kind of high cationic degree and good wet strength organic silicon modified cationic water-based polyurethane paper wet strength agent; the present invention uses Water is a dispersant, non-toxic, non-polluting, and has good compatibility. It avoids the existence of free formaldehyde and organic halides in traditional wet strength agents, and is environmentally friendly and safe.

Description

A kind of organosilicon modified cationic waterborne polyurethane paper wet strength agent and preparation method

technical field

The invention relates to the technical field of chemistry, in particular to an organosilicon-modified cationic water-based polyurethane paper wet strength agent and a preparation method thereof.

Background technique

Water-based polyurethane (WPU) uses water as a solvent, has the characteristics of non-toxic, non-polluting, safe, reliable, good compatibility, and easy to modify, and has good applications in the fields of coatings, adhesives, textiles, and papermaking. The precipitation of free formaldehyde and the presence of organic chlorine in traditional paper wetting strength agents will cause certain harm to the environment and human body. Therefore, water-based polyurethane has become a hot spot in the research of wet strength agents in the paper industry in recent years. Blocked cationic water-based polyurethane can generate electrostatic attraction with hydroxyl groups in paper fibers, form physical crosslinking, increase paper strength to a certain extent, and seal and store active isocyanate groups at the same time. When heated to the unblocking temperature, the originally blocked isocyanate groups The groups are released and chemically cross-linked with the reactive groups on the cellulose macromolecular chains to increase the wet strength of the paper. However, the hardness, water resistance and mechanical properties of a single end-capped cationic waterborne polyurethane coating film are poor, which affects its promotion and application in paper wet strength agents to a certain extent. Cationicity and reactivity are two necessary conditions to improve the paper wet strength agent, which are mainly reflected in the improvement of cationic degree and crosslinking enhancement modification in cationic waterborne polyurethane.

Chinese Patent Publication No. CN102796237B discloses a dihydroxy cationic hydrophilic chain extender and its application in the synthesis of cationic waterborne polyurethane dispersions. The invention synthesizes a cationic hydrophilic chain extender of a diol containing a tertiary amine group of a secondary alcohol Cationic water-based polyurethane dispersion is prepared, which can be used for the middle and bottom coating of genuine leather and artificial leather, the primer of wood, the sizing agent on the surface of paper, the anti-pilling agent in textile treatment, the color fixing agent of fabric and the antistatic agent. The invention is similar to most cationic water-based polyurethanes, and uses tertiary amino diols as chain extenders to obtain cationic water-based polyurethanes with hard segments containing cationic groups. This method has limitations in increasing the degree of cationicity. The amount of tertiary amino chain extender directly affects the physical crosslinking of hydrogen bonds between polyurethane hard segments. Excessive use will lead to severe phase separation, thereby destroying the mechanical properties of the material.

Silicone resin has the advantages of low surface energy, water resistance, high and low temperature resistance, and flame retardancy. In the existing preparation methods, linear polysiloxane-modified waterborne polyurethane containing active groups is the main method, and the water resistance has been improved. However, severe phase separation makes the storage stability of the emulsion and the mechanical properties of the coating film poor.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies of the prior art, and provide a silicone-modified cationic water-based polyurethane paper wet strength agent with high cationicity and good crosslinking mechanical properties and a preparation method thereof.

The purpose of the present invention is achieved through the following technical solutions:

A kind of organosilicon modified cationic water-based polyurethane paper wet strength agent, comprises following raw material by weight part:

Further, the molecular weight of the polyether diol is 1000-2000, the molecular weight of the tertiary amino polyether diol is 500-2000, and the molecular weight of the polyether triol is 500-2000; specifically, the poly The ether diol is at least one of polyoxypropylene diol, polyoxyethylene diol, and polytetrahydrofuran diol; the tertiary amino polyether diol is a tertiary amino polyoxyethylene diol; the polyether triol is poly Propylene oxide triol.

Further, the polyether diol is a polyoxypropylene diol or polytetrahydrofuran diol with a molecular weight of 1000; the tertiary amino polyether diol is a tertiary amino polyoxyethylene diol with a molecular weight of 1000; the poly The ether triol is a polyoxypropylene triol with a molecular weight of 1000.

Further, the amount of the tertiary amino polyether diol is 5-20% of the total molar content of the polyether diol, and the molar ratio of the polyether diol to polyether triol is 1.5-9:1.

Further, the isocyanate is at least one of toluene diisocyanate, diphenylmethane diisocyanate and isophorone diisocyanate, and the isocyanate index is 1.1-1.3.

Further, the cationic hydrophilic chain extender is a dihydroxy compound containing a tertiary amino group.

Further, the blocking agent is any one of methyl ethyl ketone oxime, imidazole, and sodium bisulfite, and its dosage is 1-20% of the molar content of isocyanate.

Further, the organosilicon modifier is N-(β-aminoethyl)-γ-aminopropylmethyldimethoxysilane, and its dosage is 1-20% of the molar content of isocyanate.

Further, the molar ratio of the end-capping agent to the organosilicon modifier is 0.5-2:1.

The preparation method of above-mentioned organosilicon-modified cationic waterborne polyurethane paper wet strength agent comprises the following steps:

S1. React polyether diol, tertiary amino polyether diol, polyether triol, dibutyltin dilaurate and isocyanate at 65-80°C for 2-3 hours;

S2. Cool down to 40°C, add a cationic hydrophilic chain extender, and react for 2-3 hours;

S3. Adding an end-capping agent to react for 2-3 hours, then adding glacial acetic acid to form a quaternary ammonium salt cation to obtain a polyurethane prepolymer;

S4. Then add a hydrated silicone modifier, emulsify and disperse for 1-2 hours, and obtain a silicone-modified cationic water-based polyurethane paper wet strength agent;

In the above preparation process, the viscosity of the system is adjusted by adding acetone.

Further, the amount of the cationic hydrophilic chain extender is 5-10% of the total mass of the polyurethane prepolymer.

Further, the method also includes a pretreatment step before carrying out, and the pretreatment specifically includes vacuumizing and dehydrating polyether diol, tertiary amino polyether diol and polyether triol at 110-120°C for 1.5h .

The application of the silicone-modified cationic water-based polyurethane paper wet strength agent is applied to paper surface treatment or wet end strengthening.

The principle of the present invention: both tertiary amino groups are introduced into the soft and hard segment structure of polyurethane molecules, and are modified by organic silicon to solve the problems of low cationicity and poor mechanical properties of water-based polyurethane; the tertiary amino polyether diol is introduced into the soft segment of polyurethane In the process, by mixing with polyether diol and polyether triol, dehydrating and drying, reacting with isocyanate, and then adding a cationic chain extender, blocking, neutralizing, dispersing, and modifying to obtain a silicone-modified cationic water-based polyurethane paper wet strength agent The present invention improves the cationic degree of water-based polyurethane, has strong binding force with paper fibers, can react with hydroxyl groups on the surface of paper fibers after unsealing, and can be used in paper surface treatment and wet end enhancement after silicone modification, which can significantly Improve the mechanical properties of paper.

The beneficial effects of the present invention are: the present invention breaks through the traditional preparation method of cationic water-based polyurethane, introduces both tertiary amino groups into the molecular soft segment and hard segment structure, forms quaternary ammonium salt cations after acid neutralization, improves cationic degree, and is better Adsorbed on the negatively charged paper fibers, it can be quickly and completely retained; through organic silicon modification, the crosslink density is increased to form a chemical network structure, and it can be used on paper to form a high cationic degree and wet strength. A good silicone-modified cationic water-based polyurethane paper wet strength agent; the invention uses water as a dispersant, is non-toxic, non-polluting, safe, reliable, and has good compatibility, and avoids the formation of free formaldehyde and organic halides in traditional wet strength agents. Existence is conducive to environmental protection.

detailed description

The technical solution of the present invention will be further described in detail below in conjunction with specific examples, but the protection scope of the present invention is not limited to the following description.

Example 1

A silicone-modified cationic water-based polyurethane paper wet strength agent, prepared by the following method:

S1. Add 11.1 g of tertiary amino polyoxyethylene diol, 100 g of polytetrahydrofuran diol, and 49.3 g of polyoxypropylene triol with a number-average molecular weight of 1000 after vacuum dehydration to a four-necked bottle equipped with a reflux condenser In the middle, stir, heat up, and when the temperature rises to 65-80°C, add 0.001g of dibutyltin dilaurate, 102.8g of isophorone diisocyanate and 37ml of acetone, and react for 2-3h;

S2. Cool down to 40°C, add 22.1g of N,N-dimethyldiethanolamine, control the appropriate dropping rate, add 18ml of acetone to reduce the viscosity, and extend the chain reaction for 2-3h;

S3. Then add 3.2 g of methyl ethyl ketone oxime and react for 2-3 hours, then add 11.8 g of glacial acetic acid to form a quaternary ammonium salt cation, and complete the reaction to obtain a polyurethane prepolymer;

S4. Finally, add 700.7 g of deionized water and 15.3 g of N-(β-aminoethyl)-γ-aminopropylmethyldimethoxysilane to emulsify and disperse at high speed for 1-2 hours to obtain a solid content of 30%. Silicone-modified cationic waterborne polyurethane paper wet strength agent.

Example 2

A silicone-modified cationic water-based polyurethane paper wet strength agent, prepared according to the method described in Example 1, including the following raw materials: tertiary amino polyoxyethylene glycol 5g, polytetrahydrofuran glycol 100g, polyoxypropylene triol 46.7 g, 93.4g of isophorone diisocyanate, 20.9g of N,N-dimethyldiethanolamine, 3.1g of methyl ethyl ketoxime, 10.8g of glacial acetic acid, 662.9g of deionized water, N-(β-aminoethyl)-γ - Aminopropylmethyldimethoxysilane 15.3 g.

Example 3

A silicone-modified cationic water-based polyurethane paper wet strength agent, prepared according to the method described in Example 1, including the following raw materials: tertiary amino polyoxyethylene glycol 25g, polytetrahydrofuran diol 100g, polyoxypropylene triol 55.4 g, 115g of isophorone diisocyanate, 25g of N,N-dimethyldiethanolamine, 3.5g of methyl ethyl ketoxime, 15g of glacial acetic acid, 800g of deionized water, N-(β-aminoethyl)-γ-aminopropyl Methyldimethoxysilane 18g.

Example 4

A silicone-modified cationic water-based polyurethane paper wet strength agent, prepared according to the method described in Example 1, comprising the following raw materials: tertiary amino polyoxyethylene glycol 11.1g, polytetrahydrofuran glycol 100g, polyoxypropylene triol 12.3g, 71.9g of isophorone diisocyanate, 15.5g of N,N-dimethyldiethanolamine, 3.3g of methyl ethyl ketoxime, 8.5g of glacial acetic acid, 517.1g of deionized water, N-(β-aminoethyl)- 10.7 g of γ-aminopropylmethyldimethoxysilane.

Example 5

A silicone-modified cationic water-based polyurethane paper wet strength agent, prepared according to the method described in Example 1, comprising the following raw materials: tertiary amino polyoxyethylene glycol 11.1g, polytetrahydrofuran glycol 100g, polyoxypropylene triol 4g, 65g of isophorone diisocyanate, 14.7g of N,N-dimethyldiethanolamine, 3.1g of methyl ethyl ketone oxime, 8.1g of glacial acetic acid, 450g of deionized water, N-(β-aminoethyl)-γ-ammonia Propylmethyldimethoxysilane 10.2g.

Example 6

A silicone-modified cationic water-based polyurethane paper wet strength agent, prepared according to the method described in Example 1, comprising the following raw materials: tertiary amino polyoxyethylene glycol 11.1g, polyoxypropylene glycol 100g, polyoxypropylene tri 49.3g alcohol, 102.8g isophorone diisocyanate, 22.1g N,N-dimethyldiethanolamine, 3.2g methyl ethyl ketoxime, 11.8g glacial acetic acid, 700.7g deionized water, N-(β-aminoethyl) - 15.3 g of γ-aminopropylmethyldimethoxysilane.

Example 7

A silicone-modified cationic water-based polyurethane paper wet strength agent, prepared according to the method described in Example 1, including the following raw materials: tertiary amino polyoxyethylene glycol 11.1g, polytetrahydrofuran glycol 100g, polyoxypropylene triol 49.3g, 102.8g of isophorone diisocyanate, 22.1g of N,N-dimethyldiethanolamine, 8.1g of methyl ethyl ketoxime, 11.8g of glacial acetic acid, 712.1g of deionized water, N-(β-aminoethyl)- 9.5 g of γ-aminopropylmethyldimethoxysilane.

Example 8

A silicone-modified cationic water-based polyurethane wet strength agent for paper is prepared according to the method described in Example 1, including the following raw materials: 25 g of tertiary amino polyoxyethylene glycol, 100 g of polytetrahydrofuran glycol, and a number-average molecular weight of 2000 Polyoxypropylene triol 112g, isophorone diisocyanate 115g, N,N-dimethyldiethanolamine 25g, methyl ethyl ketoxime 15g, glacial acetic acid 14.1g, deionized water 880g, N-(β-aminoethyl)- 8.8 g of γ-aminopropylmethyldimethoxysilane.

Example 9

A silicone-modified cationic water-based polyurethane paper wet strength agent, prepared according to the method described in Example 1, comprising the following raw materials: 5.6 g of tertiary aminopolyoxyethylene glycol, 100 g of polytetrahydrofuran glycol, and a number average molecular weight of 500 Polyoxypropylene triol 4g, isophorone diisocyanate 65g, N,N-dimethyldiethanolamine 14g, imidazole 3g, glacial acetic acid 7.4g, deionized water 450g, N-(β-aminoethyl)- 3.5 g of γ-aminopropylmethyldimethoxysilane.

Example 10

A silicone-modified cationic water-based polyurethane paper wet strength agent, prepared according to the method described in Example 1, including the following raw materials: tertiary amino polyoxyethylene glycol 11.1g, polytetrahydrofuran glycol 100g, polyoxypropylene triol 49.3g, 102.8g of isophorone diisocyanate, 22.1g of N,N-dimethyldiethanolamine, 12.9g of methyl ethyl ketoxime, 11.8g of glacial acetic acid, 723.3g of deionized water, N-(β-aminoethyl)- 3.8 g of γ-aminopropylmethyldimethoxysilane.

The above descriptions are only preferred embodiments of the present invention. It should be understood that the present invention is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and Modifications can be made within the scope of the ideas described herein, by virtue of the above teachings or skill or knowledge in the relevant art. However, changes and changes made by those skilled in the art do not depart from the spirit and scope of the present invention, and should all be within the protection scope of the appended claims of the present invention.

Claims (10)

1. a kind of organic-silicon-modified cation aqueous polyurethane wet strengthening agents for papermaking, it is characterised in that including following raw material with weight Part meter：

2. a kind of organic-silicon-modified cation aqueous polyurethane wet strengthening agents for papermaking according to claim 1, it is characterised in that The molecular weight of the PTMEG is 1000-2000, and the molecular weight of the tertiary amino PTMEG is 500-2000, the polyethers The molecular weight of triol is 500-2000；Specifically, the PTMEG is polyoxypropyleneglycol, Polyoxyethylene glycol, gathers At least one of erythritan；The tertiary amino PTMEG is tertiary amino Polyoxyethylene glycol；The polyether triol For polypropylene oxide triol.

3. a kind of organic-silicon-modified cation aqueous polyurethane wet strengthening agents for papermaking according to claim 1, it is characterised in that The tertiary amino PTMEG consumption is rubbing for the 5-20% of PTMEG total moles content, the PTMEG and polyether triol You are than being 1.5-9：1.

4. a kind of organic-silicon-modified cation aqueous polyurethane wet strengthening agents for papermaking according to claim 1, it is characterised in that The isocyanates are toluene di-isocyanate(TDI), methyl diphenylene diisocyanate, in isoflurane chalcone diisocyanate at least One kind, isocyanate index are 1.1～1.3.

5. a kind of organic-silicon-modified cation aqueous polyurethane wet strengthening agents for papermaking according to claim 1, it is characterised in that Dihydroxy compounds of the cationic hydrophilic chain extender for tertiary-amino-containing.

6. a kind of organic-silicon-modified cation aqueous polyurethane wet strengthening agents for papermaking according to claim 1, it is characterised in that The end-capping reagent is methyl ethyl ketoxime, imidazoles, any one in sodium sulfite, 1- of its consumption for isocyanates molar content 20%.

7. a kind of organic-silicon-modified cation aqueous polyurethane wet strengthening agents for papermaking according to claim 1, it is characterised in that The organosilicon modifier is N- (β-aminoethyl)-γ-aminopropyltriethoxy dimethoxysilane, and its consumption is isocyanates mole The 1-20% of content.

8. a kind of organic-silicon-modified cation aqueous polyurethane wet strengthening agents for papermaking according to claim 1, it is characterised in that The end-capping reagent is 0.5-2 with the mol ratio of organosilicon modifier：1.

9. a kind of preparation of cation aqueous polyurethane wet strengthening agents for papermaking organic-silicon-modified as described in claim 1-8 any one Method, it is characterised in that comprise the following steps：

S1. by PTMEG, tertiary amino PTMEG, polyether triol, dibutyl tin laurate and isocyanates at 65-80 DEG C Lower reaction 2-3h；

S2. 40 DEG C are cooled to, cationic hydrophilic chain extender is added, 2-3h is reacted；

S3. end-capping reagent reaction 2-3h is added, glacial acetic acid is added and is formed quaternary ammonium salt cationic, obtain base polyurethane prepolymer for use as；

S4. water and organosilicon modifier are added, emulsion dispersion 1-2h obtains organic-silicon-modified cation aqueous polyurethane paper Wet strength agent；

In above-mentioned preparation process, by adding acetone regulation system viscosity.

10. a kind of cation aqueous polyurethane wet strengthening agents for papermaking organic-silicon-modified as described in claim 1-8 any one should With, it is characterised in that it is applied to paper surface and processes or wet end reinforcement.