1. The aqueous coating liquid for the DuPont paper is prepared from the following raw materials in parts by weight based on 100 parts by weight:

2. the aqueous coating liquid for DuPont paper according to claim 1, wherein the ethylene-acrylic acid copolymer is obtained by copolymerizing 45 to 55 wt% of ethylene and 20 to 45 wt% of acrylic acid.

3. The aqueous dupont coating solution as claimed in claim 1, wherein the polyurethane resin is prepared from an organic polyisocyanate selected from one or more of TDI, MDI and PAPI; the oligomeric polyol is selected from one or more of polyethylene glycol, ethylene glycol, hexylene glycol and glycerol.

4. The aqueous coating solution for dupont according to claim 1, wherein the nanocellulose is selected from one or more of cellulose nanofibers, cellulose nanocrystals and bacterial nanocellulose; the silica is selected from fumed silica.

5. The aqueous coating liquid for dupont according to claim 1, wherein the composition is prepared by mixing the following components in a mass ratio of 1: (0.95-1.05) a mixture of oxazoline and N-hydroxysuccinimide.

6. The aqueous dupont coating solution as claimed in claim 1, wherein the content of the silica is 3 to 4 parts by weight.

7. The aqueous coating liquid for DuPont according to claim 1, wherein the content of the synthetic agent is 0.2 to 0.3 part by weight.

8. The method for preparing an aqueous coating liquid for dupont according to claim 1, comprising the steps of:

A) mixing 8-15 parts by weight of deionized water and 8-15 parts by weight of ethanol to obtain ethanol diluent;

B) mixing the rest of deionized water by weight, 15-30 parts of ethylene-acrylic acid copolymer by weight, 8-15 parts of polyurethane resin by weight, 2-5 parts of silicon dioxide by weight, 0.01-0.06 part of nano-cellulose by weight and 0.1-0.4 part of synthetic agent by weight to obtain the aqueous coating liquid for the DuPont paper.

9. The method according to claim 8, wherein the aqueous coating liquid has a solid content of 20 to 25% and a viscosity of 100 to 300 MPa/S.

Background

The DuPont paper is made up by using high-density polyethylene (HDPE) superfine fibre through the processes of spinning, laying, net-laying and hot-pressing, its composition is pure, non-irritant and has no coating layer, and its middle portion contains no adhesive, filling agent and whitening agent. It has the features of preventing down, wind prevention, heat preservation, water resistance, ventilation, easy drying, color separation, etc.

Dupont paper is used in many products such as desiccant packaging, medical packaging, protective apparel, walls, laminated roof insulation, down liners, envelopes, packaging materials, and automotive jacketing. However, the dupont paper is light and thin, and the fibers are not uniform, so that the coating amount of the coating on the dupont paper is not easy to control, the problems of non-uniform coating, coating breakpoints and the like are easy to occur, and the printing effect of the dupont paper is seriously influenced; and the waterproof effect of the DuPont paper is general, and the effect of soaking water and kneading without influencing printing cannot be achieved.

Disclosure of Invention

The invention aims to provide the aqueous coating liquid for the DuPont paper, which has good water resistance and can not fall off ink after being kneaded.

In view of the above, the present application provides an aqueous coating solution for dupont paper, which is prepared from the following raw materials, by weight, 100 parts:

preferably, the ethylene-acrylic acid copolymer is obtained by copolymerizing 45-55 wt% of ethylene and 20-45 wt% of acrylic acid.

Preferably, the polyurethane resin is prepared from organic polyisocyanate and oligomeric polyol, wherein the organic polyisocyanate is selected from one or more of TDI, MDI and PAPI; the oligomeric polyol is selected from one or more of polyethylene glycol, ethylene glycol, hexylene glycol and glycerol.

Preferably, the nanocellulose is selected from one or more of cellulose nanofibers, cellulose nanocrystals and bacterial nanocellulose; the silica is selected from fumed silica.

Preferably, the synthesis agent is prepared from the following components in a mass ratio of 1: (0.95-1.05) a mixture of oxazoline and N-hydroxysuccinimide.

Preferably, the content of the silica is 3 to 4 parts by weight.

Preferably, the content of the synthetic agent is 0.2-0.3 part by weight.

The application also provides a preparation method of the aqueous coating liquid for dupont, which comprises the following steps:

A) mixing 8-15 parts by weight of deionized water and 8-15 parts by weight of ethanol to obtain ethanol diluent;

B) mixing the rest of deionized water by weight, 15-30 parts of ethylene-acrylic acid copolymer by weight, 8-15 parts of polyurethane resin by weight, 2-5 parts of silicon dioxide by weight, 0.01-0.06 part of nano-cellulose by weight and 0.1-0.4 part of synthetic agent by weight to obtain the aqueous coating liquid for the DuPont paper.

Preferably, the solid content of the aqueous coating liquid is 20-25%, and the viscosity is 100-300 MPa/S.

The application provides an aqueous coating liquid for DuPont paper, which is prepared from ethylene-acrylic acid copolymer, polyurethane resin, silicon dioxide, nano cellulose, a synthetic agent, ethanol and deionized water; the nanocellulose in the aqueous coating liquid for the DuPont paper is used for dispersing the silicon dioxide, so that the silicon dioxide has a good distribution effect, the aqueous coating liquid can be arranged closely and has a smooth surface, meanwhile, the printing ink can be more firmly fixed on the surface of the coating, the ink absorption speed is accelerated, the color density value is improved, the color of a printed image is fuller and more brilliant, and the color reducibility is better; furthermore, the mixture of oxazoline and N-hydroxysuccinimide is used as a synthesis agent to react with carboxyl in the aqueous polyurethane resin emulsion and acrylic acid, so that the water resistance of the aqueous primer can be improved.

Detailed Description

For a further understanding of the invention, reference will now be made to the preferred embodiments of the invention by way of example, and it is to be understood that the description is intended to further illustrate features and advantages of the invention, and not to limit the scope of the claims.

In view of the problems that DuPont paper is general in waterproofness and the printing effect is influenced by kneading of bubble water in the prior art, the invention provides the aqueous coating liquid which is good in water resistance and free of ink dropping after kneading, the viscosity of the coating liquid is 100-300 Mpa/S, the high viscosity is easy to coat uniformly, and the effects of good water resistance effect and good printing adhesion force are finally achieved. Specifically, the application provides an aqueous coating liquid for DuPont paper, which is prepared from the following raw materials in 100 parts by weight:

in the coating liquid, the ethylene-acrylic acid copolymer is prepared from 45-85 wt% of ethylene and 20-45 wt% of acrylic acid; the resin is obtained by copolymerizing an ethylene monomer and an acrylic acid monomer in a high-pressure reaction kettle by utilizing free radical polymerization reaction. The content of the ethylene-acrylic acid copolymer is 15-30 parts by weight, and more specifically, the content of the ethylene-acrylic acid copolymer is 18-25 parts by weight. The ethylene-acrylic acid copolymer provides printing adhesion between the coating liquid and the electronic ink, and if the content is less than the above range, the phenomena of fading of printing colors and falling of the printing ink occur, and if the content is greater than the above range, the ratio of the ethylene-acrylic acid copolymer to the polyurethane resin is damaged, which affects the performance of the polyurethane resin.

The polyurethane resin is prepared by reacting organic polyisocyanate and oligomeric polyol; the organic polyisocyanate is selected from one or more of TDI, MDI and PAPI, and the oligomeric polyol is one or more of polyethylene glycol with the molecular weight of 800-1000, ethylene glycol, hexanediol and glycerol. The polyurethane resin is used for providing coating base material adhesion between a coating liquid and a base material, and the content of the polyurethane resin is 8-15 parts by weight, more specifically, the content of the well-known polyurethane is 10-14 parts by weight; if the content of the polyurethane resin is less than the above range, the coating adhesion of the base material is not firm, the coating removal phenomenon occurs to further affect the printing adhesion, and if the content is greater than the above range, the performance of the ethylene-acrylic resin is affected.

The silica is in particular fumed silica. Fumed silica refers to silica that decomposes in a flow of oxyhydrogen gas to yield a silica with very high specific surface area and fluffy feel. The gas phase silicon dioxide has the advantages of small particle size, high purity, good dispersibility and the like. Meanwhile, the silicon dioxide can form a microporous structure on the surface of the paper, can inhibit the migration of the ink to the X direction and the Y direction, and can also play a role in fixing the ink and quickly drying. The content of the silica is 2 to 5 parts by weight, and more specifically, the content of the silica is 3 parts by weight, 4 parts by weight or 5 parts by weight. If the content of the silicon dioxide is lower than the range, no ink absorption effect is generated, if the content of the silicon dioxide is too high, the emulsion is unstable, the coating is opaque, and the factor effect is influenced.

The nano-cellulose is selected from one or more of cellulose nano-fiber (CNF), cellulose nano-crystal (CNC) and bacterial nano-cellulose (BNC). The nano-cellulose reacts with the silicon dioxide, so that the particle size of silicon dioxide particles is reduced, the porosity is reduced, the particle size of the particles in the solution is reduced, the surface is smooth, the light reflection is more, and the nano-cellulose has a small size effect, so that the glossiness of the printed pearlescent paper is increased under the combined action of the nano-cellulose and the silicon dioxide. The content of the nanocellulose is 0.01-0.06 parts by weight, and more specifically, the content of the nanocellulose is 0.02 parts by weight, 0.03 parts by weight, 0.04 parts by weight, 0.05 parts by weight or 0.06 parts by weight.

The synthetic agent is a mixture of oxazoline and N-hydroxysuccinimide in a mass ratio of 1: 0.95-1.05; oxazoline and N-hydroxysuccinimide can react with carboxyl, and the combined action achieves good water-resistant effect. The content of the synthetic agent is 0.1-0.4 part by weight, and more specifically, the content of the synthetic agent is 0.1 part by weight, 0.2 part by weight, 0.3 part by weight or 0.4 part by weight. If the content of the synthetic agent is too large, the synthetic agent is excessively crosslinked with the polyurethane resin and the ethylene-acrylic acid resin, so that the performances of the polyurethane resin and the ethylene-acrylic acid resin are affected.

The application also provides a preparation method of the aqueous coating liquid, which comprises the following steps:

A) mixing 8-15 parts by weight of deionized water and 8-15 parts by weight of ethanol to obtain ethanol diluent;

B) mixing the rest of deionized water by weight, 15-30 parts of ethylene-acrylic acid copolymer by weight, 8-15 parts of polyurethane resin by weight, 2-5 parts of silicon dioxide by weight, 0.01-0.06 part of nano-cellulose by weight and 0.1-0.4 part of synthetic agent by weight to obtain the aqueous coating liquid for the DuPont paper.

More specifically, the preparation method of the coating liquid comprises the following steps:

adding 8-15 parts of deionized water and 8-15 parts of ethanol into a reaction kettle, and stirring at room temperature for 5-10 min at a stirring speed of 80-100 revolutions per minute to obtain an ethanol diluent for later use;

adding the rest soft water into a reaction kettle, adding the ethylene-acrylic acid polymer and the polyurethane resin into the reaction kettle according to the proportion, starting stirring, stirring at the speed of 100-120 r/min for 5-10 min, adding the silicon dioxide and the nano cellulose at normal temperature, stirring for 1-5 min, then continuously adding the synthesis agent, and continuously stirring for 20-30 min to obtain the waterproof ink-absorption water-based coating liquid for the DuPont paper. The solid content of the coating liquid is 20-25%, and the viscosity is 100-300 MPa/S.

The coating liquid is coated on a machine, the dry film thickness of the coating is 2-3 g/square meter, and a finished product with good water resistance, full color and good adhesive force can be obtained after printing.

The aqueous coating liquid for the DuPont paper provided by the application applies the nanocellulose to disperse the fumed silica, so that the silica obtains a good dispersing effect; with the addition of the nano-cellulose, the smaller the dispersed particle size of the silicon dioxide in the solution is, the smaller the particle size of the silicon dioxide particles fills up the pores between the fibers, the roughness of the paper pattern is reduced, the leveling property of the aqueous coating liquid is utilized to uniformly fill the silicon dioxide particles in the larger pores on the surface of the paper, a large number of capillaries are formed, the tight arrangement and the smooth surface of the aqueous coating liquid are realized, meanwhile, the printing ink can be more fixed on the surface of the coating, the ink absorption speed is accelerated, the color density value is improved, and the printed image is fuller and brighter in color and better in color reducibility; furthermore, the mixture of oxazoline and N-hydroxysuccinimide is used as a synthesis agent to react with carboxyl in the aqueous polyurethane resin emulsion and acrylic acid, so that the water resistance of the aqueous primer can be improved.

For further understanding of the present invention, the aqueous coating solution for dupont paper and the preparation method thereof provided by the present invention are described in detail below with reference to examples, and the scope of the present invention is not limited by the following examples.

Example 1

Adding 8 parts of deionized water and 8 parts of ethanol into a reaction kettle, and stirring at room temperature for 5min at the stirring speed of 80 revolutions per minute to obtain ethanol diluent for later use;

58.89 parts of soft water is added into a reaction kettle, 15 parts of ethylene-acrylic acid polymer and 8 parts of polyurethane resin are added into the reaction kettle, stirring is started, stirring is carried out for 5min at the speed of 100r/min, 2 parts of silicon dioxide and 0.01 part of nano-cellulose are added at normal temperature, stirring is carried out for 1min, then 0.1 part of synthetic agent is added, and stirring is carried out continuously for 20min, so that the waterproof ink-absorption water-based coating liquid for the DuPont paper is obtained.

The coating liquid is coated on a machine, the dry film thickness of the coating is 2.5 g/square meter, a sample is obtained after HP Indigo printing, the printed sample is whitened after being soaked in water for 24 hours, the color difference value tested by a color difference meter is 1.0, and the adhesive force reaches 1 level of the standard GB/T5210-1985.

Example 2

Adding 12 parts of deionized water and 12 parts of ethanol into a reaction kettle, and stirring at room temperature for 5min at the stirring speed of 80 revolutions per minute to obtain ethanol diluent for later use;

36.66 parts of soft water is added into a reaction kettle, 25 parts of ethylene-acrylic acid polymer and 10 parts of polyurethane resin are added into the reaction kettle, stirring is started, stirring is carried out for 5min at the speed of 100r/min, 4 parts of silicon dioxide and 0.04 part of nano-cellulose are added at normal temperature, stirring is carried out for 1min, then 0.3 part of synthetic agent is added, and stirring is carried out continuously for 20min, so that the waterproof ink-absorption water-based coating liquid for the DuPont paper is obtained.

The coating liquid is coated on a machine, the dry film thickness of the coating is 2.5 g/square meter, a sample is obtained after HP Indigo printing, the printed sample is whitened after being soaked in water for 72 hours, the color difference value tested by a color difference meter is 0.7, and the adhesive force reaches 0 level of the standard GB/T5210-1985.

Example 3

Adding 15 parts of deionized water and 15 parts of ethanol into a reaction kettle, and stirring at room temperature for 5min at the stirring speed of 80 revolutions per minute to obtain ethanol diluent for later use.

58.89 parts of soft water is added into a reaction kettle, 30 parts of ethylene-acrylic acid polymer and 15 parts of polyurethane resin are added into the reaction kettle, stirring is started, the mixture is stirred for 5min at the speed of 100r/min, 5 parts of silicon dioxide and 0.06 part of nano-cellulose are added at normal temperature, the mixture is stirred for 1min, 0.4 part of synthetic agent is added, and the stirring is continued for 20min, so that the waterproof ink-absorption water-based coating liquid for the DuPont paper is obtained.

The coating liquid is coated on a machine, the dry film thickness of the coating is 2.5 g/square meter, a sample is obtained after HP Indigo printing, the printed sample is whitened after being soaked in water for 100 hours, the color difference value tested by a color difference meter is 0.4, and the adhesive force reaches 0 level of the standard GB/T5210-1985.

Comparative example 1

Under the same operation of example 1, the other components and contents were unchanged, fumed silica was not added, the test results were otherwise unchanged, and the color difference value was 1.5; the same nanocellulose was not added, and the test results were otherwise unchanged, with a color difference of 1.5.

Comparative example 2

Under the same operation of example 1, other components and contents are unchanged, no oxazoline is added into the synthetic agent, the test result is unchanged, and the product turns white after being soaked in water for 12 hours; the same synthetic agent is not added with N-hydroxysuccinimide, and the test result is unchanged, and the synthetic agent turns white after being soaked in water for 12 hours.

Comparative example 3

Under the same operation of example 1, the other components and the contents are unchanged, the content of the synthetic agent is 1 part, the content of the soft water is 58.8 parts, the test result shows that the water after foaming is whitened after 100 hours, and the adhesion force reaches grade 2 of the standard GB/T5210-1985.

The above description of the embodiments is only intended to facilitate the understanding of the method of the invention and its core idea. It should be noted that, for those skilled in the art, it is possible to make various improvements and modifications to the present invention without departing from the principle of the present invention, and those improvements and modifications also fall within the scope of the claims of the present invention.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.