Paper water-based paint and preparation method thereof

Abstract

The invention provides a paper water-based paint and a preparation method thereof. The paper water-based paint comprises the following active ingredients in parts by weight: 1-80 parts of water-based polyurea dispersion; 0.1-0.5 part of a wetting dispersant; 0.1 to 0.5 part of a defoaming agent; 0.2 to 0.6 part of a thickening agent; the preparation method comprises the following steps: stirring the solvent, the wetting dispersant and the defoaming agent in parts by weight, adding the water-based polyurea dispersion, fully dispersing, and adding the thickening agent to obtain the paper water-based paint; the water-based polyurea dispersion is used as a main agent film forming matter, and a continuous film is formed on paper, so that a basic structure is provided for products such as paint and printing ink, and key properties such as protection, decoration and durability are endowed.

Description

Technical Field

[0001] The invention relates to a water-based paper paint and a preparation method thereof, belonging to the technical field of preparation of functional paints. Background Art

[0002] In the prior art, the traditional method of covering paper is to adhere a layer of polyethylene or polypropylene film to the paper. The processing process includes gluing, laminating, etc., and it is also necessary to wait for the interlayer adhesive to solidify. The overall production efficiency is low and the durability of the plastic film is difficult to guarantee. When the product is used for a long time, the coating tends to peel off from the edges and corners. With the continuous increase in the overall demand for paper products, book covers, advertising posters, commodity outer packaging cartons, decorative paper bags, etc. all need to be coated and decorated before use, and paper spray painting is to apply the coating to the surface of the paper page, and then dry it to form a covering layer with a porous structure. By pre-filming the paper before inking, the appearance and optical properties of the paper are improved to improve the printability of the paper.

[0003] In recent years, due to policy requirements, the composition of water-based inks has also changed, and their effectiveness has changed accordingly. This is reflected in the poor inking effect of water-based ink on paper during the printing process. For example, on uncoated paper, water-based ink easily seeps into the paper fibers, causing quality issues such as ink bleeding and uneven color depth. On coated paper, the ink easily runs off. Furthermore, a large amount of recycled paper has a yellowish tint and low strength, making it difficult to ink. In addition, after spraying conventional polyester primer on paper, the paint film is easily affected by light, causing it to yellow. When printing a pattern on the primer film, the yellowing primer will affect the rendering of the pattern. Summary of the Invention

[0004] In order to overcome the shortcomings of the prior art, the first purpose of the present invention is to provide a water-based paint for paper; the paint film formed by the water-based paint is not easy to turn yellow, and the ink-inking effect is good; the second purpose of the present invention is to provide a method for preparing a varnish for paper, and the prepared transparent primer has stable performance and a simple preparation process.

[0005] The second object of the present invention is to provide a method for preparing the above-mentioned water-based paper paint, which has a simple process, is adaptable to industrial production, and has stable performance of the water-based paper paint.

[0006] The first object of the present invention can be achieved by adopting the following technical solution: a water-based paper paint comprising the following active ingredients in parts by weight:

[0007] 1-80 parts of aqueous polyurea dispersion;

[0008] Wetting and dispersing agent 0.1-0.5 parts;

[0009] 0.1-0.5 parts of defoaming agent;

[0010] Thickener 0.2-0.6 parts;

[0011] The aqueous polyurea dispersion was prepared by the following method:

[0012] The prepolymer synthesis steps include: adding polyetheramine or its derivative, acetone and N-methylpyrrolidone into a reactor, adding isocyanate monomer dropwise for reaction; then adding alanine, capping with hydroxy acrylate, reacting at a temperature of 60-90°C, and chain extension with aspartame polyurea resin to obtain a prepolymer;

[0013] Dispersion formation step: adding a mixed solution of acrylate monomer and initiator dropwise to the prepolymer, adding triethylamine for neutralization, and obtaining an aqueous polyurea dispersion.

[0014] Furthermore, the derivative of polyetheramine is polyetheramine-type polyaspartic acid ester.

[0015] Furthermore, during the synthesis of the prepolymer, the temperature for dropwise addition of the isocyanate monomer is 0-25°C.

[0016] Furthermore, during the synthesis of the prepolymer, after the isocyanate monomer is added dropwise, the reaction is carried out at a temperature of 25-50°C.

[0017] Furthermore, the isocyanate monomer is at least one of IPDI, HMDI, TDI and HDI.

[0018] Furthermore, in the prepolymer synthesis step, alanine is added and the temperature is kept at 25-85° C. for 1-3 hours.

[0019] Furthermore, in the prepolymer synthesis step, the prepolymer is capped with hydroxy acrylate and reacted at a temperature of 60-90° C. for 3-6 hours.

[0020] Furthermore, in the prepolymer synthesis step, chain extension is performed using aspartame polyurea resin and the prepolymer is kept warm at a temperature of 25-50°C.

[0021] Furthermore, the alanine is at least one of 2-aminoacrylic acid and 2,2-dihydroxymethylpropionic acid.

[0022] Furthermore, the hydroxy acrylate is at least one of hydroxyethyl acrylate, hydroxyethyl methacrylate, pentaerythritol triacrylate and caprolactone acrylate.

[0023] Furthermore, in the dispersion forming step, the mixed solution of the acrylate monomer and the initiator is added dropwise to the prepolymer, and the mixture is reacted at a temperature of 60-125° C. for 2-6 hours.

[0024] Furthermore, the acrylate monomer is at least three of acrylic acid, methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, sec-butyl acrylate, tert-butyl acrylate, n-propyl acrylate, cyclohexyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, methacrylic acid, methyl methacrylate, trifluoroethyl methacrylate, versatate, isobornyl acrylate, isodecyl acrylate, trihydroxymethylcyclohexyl acrylate and octadecyl acrylate.

[0025] Furthermore, the initiator is at least one of benzoyl peroxide, tert-butyl peroxide (2-ethylhexanoate) and tert-butyl peroxide 3,5,5-trimethylhexanoate.

[0026] The second object of the present invention can be achieved by adopting the following technical solution: A method for preparing a water-based paint for paper, comprising stirring 25-50 parts by weight of a solvent, 0.1-0.5 parts by weight of a wetting and dispersing agent, and 0.1-0.5 parts by weight of a defoaming agent, adding 1-80 parts by weight of an aqueous polyurea dispersion, and fully dispersing the mixture, and then adding 0.2-0.6 parts by weight of a thickener to obtain a water-based paint for paper;

[0027] The aqueous polyurea dispersion was prepared by the following method:

[0028] The prepolymer synthesis steps include: adding polyetheramine or its derivative, acetone and N-methylpyrrolidone into a reactor, adding isocyanate monomer dropwise for reaction; then adding alanine, capping with hydroxy acrylate, reacting at a temperature of 60-90°C, and chain extension with aspartame polyurea resin to obtain a prepolymer;

[0029] Dispersion formation step: adding a mixed solution of acrylate monomer and initiator dropwise to the prepolymer, adding triethylamine for neutralization, and obtaining an aqueous polyurea dispersion.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] 1. The water-based paper paint of the present invention uses a water-based polyurea dispersion as the main agent and film-forming material. By forming a continuous film on paper, it provides a basic structure for products such as coatings and inks, and imparts key properties such as protection, decoration, and durability.

[0032] 2. The paint film formed by the water-based paint for paper of the present invention is not easy to turn yellow, and the ink application effect is good;

[0033] 3. The water-based polyurea dispersion used in the water-based paper paint of the present invention forms a three-dimensional network structure through the reaction of diisocyanate and amine compounds, forming a spatial cross-linking system to increase the viscosity of the system;

[0034] 4. The preparation method of the water-based paper paint of the present invention has a simple process, is adaptable to industrial production, and has stable performance of the water-based paper paint. DETAILED DESCRIPTION

[0035] Below, in conjunction with specific embodiments, the present invention is further described:

[0036] 1. Preparation of waterborne polyurea dispersion:

[0037] The prepolymer synthesis steps are as follows: polyetheramine or polyetheramine type polyaspartic acid ester, acetone and N-methylpyrrolidone (NMP) are added into a reactor, the circulating cooling system is turned on to control the temperature at 0-25°C, isocyanate monomer is added dropwise, and the reaction is carried out at a temperature of 25-50°C; then alanine is added and the reaction is carried out at a temperature of 25-85°C for 1-3 hours, and then the reaction is terminated with hydroxy acrylate and the reaction is carried out at a temperature of 60-90°C for 3-6 hours, and aspart polyurea resin is used for chain extension, and the reaction is carried out at a temperature of 25-50°C for 2 hours to obtain a prepolymer.

[0038] The polyetheramine is selected from Zhengda ZD1200, and the derivative of the polyetheramine is polyetheramine type polyaspartic acid ester TOCPOLY NH262.

[0039] The isocyanate monomer is at least one of IPDI, HMDI, TDI and HDI, preferably IPDI and HMDI, which have relatively low activity and whose reaction with polyetheramine or its derivatives is controllable.

[0040] The alanine is at least one of 2-aminoacrylic acid and 2,2-dihydroxymethylpropionic acid.

[0041] The hydroxy acrylate is at least one of hydroxyethyl acrylate, hydroxyethyl methacrylate, pentaerythritol triacrylate (PETA) and caprolactone acrylate.

[0042] Dispersion formation step: adding the mixed solution of acrylate monomer and initiator dropwise to the prepolymer, reacting at a temperature of 60-125°C for 2-6 hours, and removing the solvent under negative pressure vacuum; adding triethylamine for neutralization to obtain an aqueous polyurea dispersion.

[0043] Among them, the acrylate monomer is at least three of acrylic acid, methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, sec-butyl acrylate, tert-butyl acrylate, n-propyl acrylate, cyclohexyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, methacrylic acid, methyl methacrylate, trifluoroethyl methacrylate, versatate, isobornyl acrylate, isodecyl acrylate, trihydroxymethylcyclohexyl acrylate, trihydroxymethylcyclohexyl acrylate and octadecyl acrylate.

[0044] The initiator is at least one of benzoyl peroxide (BPO), tert-butyl peroxide (2-ethylhexanoate) (BHET) and tert-butyl peroxide 3,5,5-trimethylhexanoate (TBPIN).

[0045] 2. Prepare water-based paint for paper by the following weight parts:

[0046]

[0047] Water, a wetting dispersant and a defoaming agent are stirred, and after the aqueous polyurea dispersion is fully dispersed, a thickener is added to obtain a water-based paper paint.

[0048] Example 1:

[0049] Preparation of aqueous polyurea dispersion:

[0050] Prepolymer synthesis steps: 200g polyetheramine ZD-1200, 70g acetone and 30g N-methylpyrrolidone (NMP) are added to a reactor, the circulating cooling system is turned on to control the temperature at 0-10°C, 113.7g IPDI is added dropwise over 2h, and the reaction is carried out at 40°C for 4h; then 15g 2,2-dimethylolpropionic acid is added and the mixture is kept at 80°C for 2h, and then 26.5g hydroxyethyl acrylate is capped and the mixture is reacted at 80°C for 5h, and 29g asparagine polyurea resin NH252 is used for chain extension, and the mixture is kept at 25-50°C for 2h to obtain a prepolymer;

[0051] Dispersion formation step: a mixture of 30 g of methyl acrylate, 40 g of isobutyl acrylate, 10 g of versatate and 0.5 g of benzoyl peroxide is added dropwise to the prepolymer, reacted at a temperature of 100° C. for 4 hours, and desolventized under negative pressure; 14.2 g of triethylamine is added for neutralization, and 523.1 g of water is added to disperse into an emulsion to obtain an aqueous polyurea dispersion with a solid content of 45.0%.

[0052] Example 2:

[0053] Preparation of aqueous polyurea dispersion:

[0054] Prepolymer synthesis steps: 234.4g of polyetheramine type polyaspartic acid ester TOCPOL Y NH262, 70g of acetone and 30g of N-methylpyrrolidone (NMP) are added to the reactor, the circulating cooling system is turned on to control the temperature at 0-10°C, 90.5g of IPDI is added dropwise, the addition is completed over 2h, and the reaction is carried out at a temperature of 40°C for 4h; then 18.4g of 2,2-dihydroxymethylpropionic acid is added and the temperature is kept at 80°C for 2h, and then 60g of pentaerythritol triacrylate is used for end-capping, and the reaction is carried out at a temperature of 80°C for 5h, and 30g of aspartame polyurea resin NH252 is used for chain extension, and the temperature is kept at 40°C for 2h to obtain a prepolymer.

[0055] Dispersion formation steps: A mixture of 30g of methyl acrylate, 40g of isobutyl acrylate, 10g of lauryl acrylate and 0.5g of benzoyl peroxide is added dropwise to the prepolymer, reacted at a temperature of 100°C for 4h, and desolventized under negative pressure vacuum; 14.2g of triethylamine is added for neutralization, and 581g of water is added to disperse into an emulsion to obtain an aqueous polyurea dispersion with a solid content of 45.0%.

[0056] Example 3:

[0057] Preparation of aqueous polyurea dispersion:

[0058] Prepolymer synthesis steps: 234.4g of polyetheramine type polyaspartic acid ester TOCPOL Y NH262, 70g of acetone and 30g of N-methylpyrrolidone (NMP) are added to a reactor, and the circulating cooling system is turned on to control the temperature at 0-10°C, and 90.5g of IPDI is added dropwise over 2 hours, and the reaction is carried out at a temperature of 40°C for 4 hours; then 12g of 2-aminoacrylic acid is added and kept at a temperature of 80°C for 2 hours, and then 70g of caprolactone acrylate is used for end-capping, and the reaction is carried out at a temperature of 80°C for 5 hours. 30g of aspartic polyurea resin NH252 is used for chain extension, and the temperature is kept at 40°C for 2 hours to obtain a prepolymer;

[0059] Dispersion formation step: a mixture of 20 g of methyl acrylate, 20 g of n-butyl acrylate, 20 g of isobornyl acrylate, 20 g of isodecyl acrylate and 0.5 g of benzoyl peroxide is added dropwise to the prepolymer, reacted at a temperature of 100° C. for 4 hours, and desolventized under negative pressure; 14.2 g of triethylamine is added for neutralization, and 517.6 g of water is added to disperse into an emulsion to obtain an aqueous polyurea dispersion with a solid content of 45.0%.

[0060] Example 4:

[0061] Preparation of aqueous polyurea dispersion:

[0062] Prepolymer synthesis steps: 234.4g of polyetheramine type polyaspartic acid ester TOCPOL Y NH262, 70g of acetone and 30g of N-methylpyrrolidone (NMP) are added to a reactor, the circulating cooling system is turned on to control the temperature at 0-10°C, 109.2g of HMDI is added dropwise over 2 hours, and the reaction is carried out at a temperature of 40°C for 4 hours; then 12g of 2-aminoacrylic acid is added and the temperature is kept at 80°C for 2 hours, and then 70.0g of caprolactone acrylate is capped and the reaction is carried out at a temperature of 80°C for 5 hours, and 30g of aspartic polyurea resin NH252 is used for chain extension, and the temperature is kept at 40°C for 2 hours to obtain a prepolymer;

[0063] Dispersion formation step: A mixture of 30g of ethyl acrylate, 40g of tert-butyl acrylate, 10g of trimethylolcyclohexyl acrylate and 0.5g of benzoyl peroxide is added dropwise to the prepolymer, reacted at a temperature of 100°C for 4h, and desolventized under negative pressure; 14.2g of triethylamine is added for neutralization, and 540.5g of water is added to disperse into an emulsion to obtain an aqueous polyurea dispersion with a solid content of 45.0%.

[0064] Example 5:

[0065] Preparation of aqueous polyurea dispersion:

[0066] Prepolymer synthesis steps: 234.4g of polyetheramine type polyaspartic acid ester TOCPOL Y NH262, 70g of acetone and 30g of N-methylpyrrolidone (NMP) are added to a reactor, the circulating cooling system is turned on to control the temperature at 0-10°C, 109.2g of HMDI is added dropwise over 2 hours, and the reaction is carried out at a temperature of 40°C for 4 hours; then 12g of 2-aminoacrylic acid is added and the temperature is kept at 80°C for 2 hours, and then 70g of caprolactone acrylate is capped and the reaction is carried out at a temperature of 80°C for 5 hours, and 30g of aspartame polyurea resin NH252 is used for chain extension, and the temperature is kept at 40°C for 2 hours to obtain a prepolymer;

[0067] Dispersion formation step: a mixture of 30g of methyl acrylate, 20g of tert-butyl acrylate, 20g of trimethylolcyclohexyl acrylate, 10g of octadecyl acrylate and 0.5g of benzoyl peroxide is added dropwise to the prepolymer, reacted at a temperature of 100°C for 4h, and desolventized under negative pressure; 14.2g of triethylamine is added for neutralization, and 540.5g of water is added to disperse into an emulsion to obtain an aqueous polyurea dispersion with a solid content of 45.0%.

[0068] Product testing:

[0069] Coating preparation:

[0070] 36.0 g of water, 0.2 g of wetting and dispersing agent BYK192, and 0.3 g of defoamer BYK021 were added to a dispersing kettle and stirred at 500 rpm for 20 min. 63.15 g of the aqueous polyurea dispersions prepared in Examples 1-4 were then added. After thorough dispersion at 800 rpm, 0.35 g of polyurea thickener BYK420 was added to obtain a water-based paper paint. The test results are shown in Table 1.

[0071] Table 1 Performance test of Examples 1-4 and Comparative Examples

[0072]

[0073] Abrasion resistance according to the standard: GB / T 13024-2016 bursting index (based on paper weight 160g / m 2 test).

[0074] As shown in Table 1, the water-based varnishes for recycled paper produced in Examples 1-5 exhibit excellent performance in terms of paper tear resistance, water resistance, adhesion, and ink color development. The varnish in Example 1 exhibits the highest hardness, due to the high crosslink density of the primary amine-based polyurea backbone, resulting in excessively high film hardness. Examples 2-5 utilize polyetheramine-based polyaspartic acid esters as their backbones. These secondary amines have lower activity than primary amine-based polyetheramines and half the crosslink density, resulting in softer varnishes and easier production control. The higher hardness in Example 2 is attributed to the trifunctional acrylate endcapping of the polyurea segments, which results in high crosslink density and increased rigidity. In contrast, in Examples 3-5, the highly flexible caprolactone acrylate-terminated polyetheramine polyurea segments, along with the polymethyl-terminated polypropylene segments introduced via free radical polymerization, exhibit excellent water resistance, toughness, and ink color development.

[0075] Hydroxyl acrylate capping of the polyurea backbone introduces acrylate double bonds, and free radical polymerization then introduces multiple methyl side chains. The urea groups and multiple methyl side chains synergistically impart excellent hydrophobicity to the product of this invention, while the polyether-type polyurea segments provide high flexibility and mechanical strength. The test results of the above examples demonstrate that this solution outperforms existing products in terms of burst resistance, water resistance, and ink color development.

[0076] Those skilled in the art can make various other corresponding changes and modifications based on the technical solutions and concepts described above, and all of these changes and modifications should fall within the scope of protection of the claims of the present invention.

Claims

1. A water-based paint for paper, characterized in that: Contains the following active ingredients in parts by weight: 1-80 parts of aqueous polyurea dispersion; Wetting and dispersing agent 0.1-0.5 parts; 0.1-0.5 parts of defoaming agent; Thickener 0.2-0.6 parts; The aqueous polyurea dispersion is prepared by the following method: The prepolymer synthesis steps include: adding polyetheramine or its derivative, acetone and N-methylpyrrolidone into a reactor, adding isocyanate monomer dropwise for reaction; then adding alanine, capping with hydroxy acrylate, reacting at a temperature of 60-90°C, and chain extension with aspartame polyurea resin to obtain a prepolymer; Dispersion formation step: adding a mixed solution of acrylate monomer and initiator dropwise to the prepolymer, adding triethylamine for neutralization, and obtaining an aqueous polyurea dispersion.

2. The water-based paper paint according to claim 1, wherein The derivative of the polyetheramine is polyetheramine type polyaspartic acid ester.

3. The water-based paper paint according to claim 1, wherein During the prepolymer synthesis, the temperature for dropwise addition of isocyanate monomer is 0-25°C.

4. The water-based paper paint according to claim 1, wherein The isocyanate monomer is at least one of IPDI, HMDI, TDI and HDI.

5. The water-based paper paint according to claim 1, wherein In the prepolymer synthesis step, alanine is added and the mixture is kept at a temperature of 25-85° C. for 1-3 hours.

6. The water-based paper paint according to claim 1, wherein In the prepolymer synthesis step, the prepolymer is capped with hydroxy acrylate and reacted at a temperature of 60-90° C. for 3-6 hours.

7. The water-based paper paint according to claim 1, wherein The hydroxy acrylate is at least one of hydroxyethyl acrylate, hydroxyethyl methacrylate, pentaerythritol triacrylate and caprolactone acrylate.

8. The water-based paper paint according to claim 1, wherein In the dispersion forming step, the mixed solution of acrylate monomer and initiator is added dropwise to the prepolymer and reacted at a temperature of 60-125° C. for 2-6 hours.

9. The water-based paper paint according to claim 1, wherein: The acrylate monomers are at least three of acrylic acid, methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, sec-butyl acrylate, tert-butyl acrylate, n-propyl acrylate, cyclohexyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, methacrylic acid, methyl methacrylate, trifluoroethyl methacrylate, versatate, isobornyl acrylate, isodecyl acrylate, trihydroxymethylcyclohexyl acrylate and octadecyl acrylate.

10. A method for preparing water-based paper paint, characterized in that: 25-50 parts by weight of solvent, 0.1-0.5 parts of wetting and dispersing agent, and 0.1-0.5 parts of defoaming agent are stirred, 1-80 parts of aqueous polyurea dispersion is added and fully dispersed, and then 0.2-0.6 parts of thickener is added to obtain a water-based paper paint; The aqueous polyurea dispersion is prepared by the following method: The prepolymer synthesis steps include: adding polyetheramine or its derivative, acetone and N-methylpyrrolidone into a reactor, adding isocyanate monomer dropwise for reaction; then adding alanine, capping with hydroxy acrylate, reacting at a temperature of 60-90°C, and chain extension with aspartame polyurea resin to obtain a prepolymer; Dispersion formation step: adding a mixed solution of acrylate monomer and initiator dropwise to the prepolymer, adding triethylamine for neutralization, and obtaining an aqueous polyurea dispersion.

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