CN110041750B

CN110041750B - Full-aqueous ink and preparation method thereof

Info

Publication number: CN110041750B
Application number: CN201910236217.5A
Authority: CN
Inventors: 石玉传
Original assignee: Shandong Huanuo Daily Chemical Co ltd
Current assignee: Shandong Huanuo Daily Chemical Co ltd
Priority date: 2019-03-27
Filing date: 2019-03-27
Publication date: 2022-06-03
Anticipated expiration: 2039-03-27
Also published as: CN110041750A

Abstract

The invention belongs to the technical field of printing, and particularly relates to full-aqueous ink and a preparation method thereof. The invention adopts hydroxyethyl methacrylate, glycidyl methacrylate, styrene and alginic acid as raw materials to prepare quaternary copolymerization water-soluble grinding resin liquid to form base materials with stable performance; the all-water-based ink prepared from the ink, the connecting material, the water-soluble auxiliary agent and water has good fluidity, high color concentration and good printability; the printed matter has high luster, good leveling property, adhesion fastness and resistance which can be compared favorably with solvent ink, and has no harmful substance residue after drying. The prints have blocking resistance, migration resistance, rub resistance and water resistance. Can be used for surface printing of shopping bags, medicine packages, transfer bags and food bags printed on the surfaces of plastic base materials such as BOPP, PET, PE/PEVA and the like.

Description

Full-aqueous ink and preparation method thereof

Technical Field

The invention belongs to the technical field of printing, and particularly relates to full-aqueous ink and a preparation method thereof.

Background

The plastic surface printing ink begins in the 60 s, and the dye and benzene are used as the ink, which is only suitable for the requirement of simple packaging. Because the dye is not migration-resistant and has insufficient light fastness, the pigment is used as the coloring agent in the later period, and the related performance of the ink is improved. Until the early 90 s, the environmental protection consciousness of the nation is improved, and the national policy and regulation are gradually improved, the solvent ink is subjected to the pain process of abandoning benzophenone, and until now, the solvent ink uses low-toxicity lipid and alcohol solvents to replace toluene, xylene, butanone and the like, so that the ink is greatly improved in the aspect of environmental protection, but the waste gas discharge is still limited by the current environmental protection regulation, the development of plastic ink is limited to a great extent, and meanwhile, the society calls for more environment-friendly water-based products to meet the requirement of printing.

The water-based ink is environment-friendly ink taking water as a solvent, and does not contain volatile organic solvent, so that the pollution of VOC emission to the atmosphere is reduced, the printing operation environment is improved, and the health of workers is facilitated. The water-based ink eliminates the harm of toxic and harmful substances in the solvent-based ink to human bodies and the pollution to packaged commodities, reduces the fire hazard and hidden danger caused by static electricity and flammable solvents, reduces the toxic residue on the surfaces of printed matters, and is convenient for cleaning printing equipment. The serial advantages of water-based ink make the water-based ink increasingly receive more attention at the present time when the environmental protection is important. The water-based ink is a necessary requirement for social progress, and has a very positive effect on improving the environment.

The stability of the existing water-based ink is generally poor, and the stability of the ink mainly refers to that the pigment dispersion performance and the rheological property of the ink keep stable and unchanged for a long time within a wide temperature change range. The problem becomes the bottleneck of the research and development of the domestic water-based pen ink, and is represented by weak preparation technology of the ink precursor pigment color paste, poor high-temperature resistance of the system, poor compatibility of the color paste system and a rheological property adjusting system and the like. In addition, aqueous inks are acceptable for image quality and durability when printed on ink-jet paper or coated substrates, but do not produce sharp, durable images when printed on non-absorbent substrates such as metal, glass, and plastic. The pigment type water-soluble ink has higher requirement on the dispersibility of the base ink, and the particle size of the base ink is generally required to be less than 1 micron; however, when the particle size of the pigment is small (less than 1 micron), aggregation easily occurs, so that the stability of the ink is poor; maintaining the dispersibility of the pigment while ensuring its low particle size is also a problem to be urgently solved.

Disclosure of Invention

The invention aims to provide the all-water ink and the preparation method thereof, the invention adopts the quaternary copolymer resin liquid as the water-soluble grinding resin liquid to prepare the base material, and the prepared base material greatly improves the stability of the base material on the premise of keeping smaller particle size, thereby preparing the all-water ink with excellent performance, and the all-water ink can be used for surface printing of plastic base materials. The all-water-based ink prepared by the invention has good water dispersibility, safety, environmental protection and low VOC content; the fluidity is good, the color density is high, and the printability is good; the printed matter has high luster, good leveling property, adhesion fastness and resistance comparable to solvent ink, and no harmful substance residue after drying. The printed matter has blocking resistance, migration resistance, rubbing resistance and water resistance. Can be used for surface printing of shopping bags, medicine packages, transfer bags and food bags printed on the surfaces of plastic base materials such as BOPP, PET, PE/PEVA and the like.

According to the first aspect of the invention, the invention provides full-water plastic surface printing ink which is prepared from the following raw materials in percentage by weight: 10-30% of base material, 50-65% of connecting material, 5% of water-soluble auxiliary agent and the balance of water;

the base material comprises the following raw materials in percentage by weight: 15-20% of water-soluble grinding resin liquid; 40-65% of pigment; 4-6% of a dispersant; 0.3 to 0.4 percent of defoaming agent; diluting the resin emulsion: 4 to 5 percent; the balance of water;

the connecting material comprises the following raw materials in percentage by weight: 60-70% of film-forming emulsion, 25-30% of non-film-forming emulsion, 3-5% of cosolvent, 3-5% of redissolving resin and the balance of water.

The preparation method of the water-soluble grinding resin liquid comprises the following steps:

adding acetone serving as a solvent into a reactor, adding 40 parts by weight of hydroxyethyl methacrylate (HEMA), 60 parts by weight of Glycidyl Methacrylate (GMA), 80 parts by weight of alginic acid (A), 200 parts by weight of styrene (S) and 5 parts by weight of dibenzoyl peroxide (BPO) under the atmosphere of nitrogen, stirring and refluxing for carrying out free radical polymerization reaction for 18-24h, then removing acetone under reduced pressure, slowly adding deionized water to adjust the non-volatile component to 30-40wt%, and finally adjusting the acid value of the resin liquid of the system to 160-180 by adopting 0.2mol/L sodium hydroxide aqueous solution to obtain the quaternary copolymerized water-soluble grinding resin liquid; the acid value is mg of potassium hydroxide required for 1g of a nonvolatile component in the water-soluble polishing resin solution;

the invention adopts hydroxyethyl methacrylate (HEMA), Glycidyl Methacrylate (GMA), styrene (S) and alginic acid (A) as raw materials to prepare the water-soluble grinding resin liquid of the four-component copolymerization of HEMA-GMA-S-A; the addition of alginic acid in the preparation process of the water-soluble grinding resin liquid can effectively improve the stability of pigment particles in the base material and play a role in flocculation resistance; can prepare a base material with small particle size and high dispersion;

preferably, the water-soluble auxiliary agent is a water-soluble dispersant, a defoaming agent, a color tone regulator, a fluidity regulator or a drying regulator.

Preferably, the pigment is lithol scarlet (P.R49:1), benzidine yellow G, phthalocyanine blue BGS (P.B15:3), phthalocyanine blue B (P.B15:3) or roller carbon black;

preferably, the letdown resin emulsion is HC-8102B type ink resin produced by Sanshui Shancheng synthetic resin Limited company; the coating has excellent film forming property and flexibility and good wear resistance; the drying speed and the adhesion fastness of the ink can be obviously improved;

the film-forming emulsion is acrylic film-forming emulsion, such as pure acrylic emulsion, styrene-acrylic emulsion or organic silicon-acrylic emulsion; for example, the aqueous acrylic emulsion produced by Green spring environmental protection technology materials Ltd has a solid content of 47%, an acid value of 55, a glass transition temperature of 30 ℃, a pH value of about 8.5 and a viscosity of 800mPa.s

The non-film-forming emulsion is an acrylic non-film-forming emulsion, such as those produced by BASF corporation

89 or

90, etc. type acrylic non-film forming emulsion.

The redissolved resin is a low molecular weight solvent type redissolved resin, and the low molecular weight solvent type redissolved resin is selected from ethyl cellulose, hydroxyl modified binary vinyl chloride-vinyl acetate copolymer, chlorinated polyolefin or styrene acrylic acid; the low molecular weight solvent is selected from alcohol, ester or ether;

preferably, the cosolvent is a water-soluble organic solvent such as ethanol, isopropanol, acetone, ethylene glycol or glycerol; the cosolvent is used for dissolving resin, improving the drying performance of the ink and adjusting the viscosity of the ink in the water-based ink.

Preferably, the preparation method of the base stock comprises the following steps:

the water, the water-soluble grinding resin liquid, the pigment, the dispersing agent and the defoaming agent are weighed according to the formula proportion and are sequentially added, the mixture is stirred by a high-speed stirrer for about 30 minutes, and then the diluted resin emulsion is added and dispersed by a high-speed grinder for 1-2 hours to obtain the base material.

Preferably, the high-speed grinding machine dispersion refers to grinding at a rotating speed of 2000-2200 rpm below 30 ℃; the grinding medium used by the high-speed grinding machine is zirconia beads with the particle size of 0.4-0.6mm, and the ball-to-material ratio is 4: 1; grinding media such as steel balls, silicon dioxide balls, silicon oxide balls, composite zirconium aluminum balls, zirconium silicate balls and the like can also be used for grinding, and the zirconium oxide balls are preferably selected in the invention; the grinding temperature is further preferably 5-10 ℃;

the production and grinding of the ink base material are the key to the success or failure of the ink, the control of grinding media, grinding temperature and the like is very strict, and a cold grinding process is adopted, otherwise, the stability of the base material is very poor. The grinding temperature, the dispersing ability and the heat dissipation ability of the grinder, the quality and the type of the grinding medium, the addition amount, the viscosity of the base material, the fineness and the luster of the base material are controlled.

In the grinding process, the solid particle pigment is ground into small particles, the pigment is made to interact with water-soluble resin liquid through resin coating to form a molecular group structure, the particles of the molecular group structure exist in a base material in the form of suspension, and the suspended particles cause flocculation of the suspended particles due to Brownian motion and interaction force (such as hydrogen bonds, Van der Waals force and electrostatic attraction force); to prevent aggregation of pigment clusters; the dispersing agent is added into the base material, so that the molecular group structure can be wetted and uniformly dispersed in the base material.

The surface tension of water in the water-based ink is high, and the water is easy to foam; the proper amount of the antifoaming agent is added into the base material, so that the foaming phenomenon of the ink is improved, the pigment can be dispersed more uniformly, and the accumulation caused by foaming is avoided;

according to another aspect of the present invention, there is provided a method of preparing an all-aqueous ink comprising:

and sequentially adding water and the water-soluble assistant into the reactor, stirring for 10-20min, then adding the binder, stirring for 20-30min, and finally adding the base material, and stirring at the rotation speed of 600-1000rpm for 1-2 hours to obtain the fully-aqueous ink.

The invention has the following advantages:

1) according to the invention, hydroxyethyl methacrylate (HEMA), Glycidyl Methacrylate (GMA), styrene (S) and alginic acid (A) are used as raw materials for preparing A water-soluble grinding resin liquid of HEMA-GMA-S-A quaternary copolymerization for the first time; the pigment has good wettability, excellent comprehensive performances of dispersibility, wear resistance and fluidity in water, can prevent the flocculation and sedimentation of the pigment in the water-based ink base material, and improves the stability of the ink;

2) the invention optimizes the grinding process of the base material, strictly controls the grinding temperature in the preparation process of the base material, ensures that the prepared base material has smaller particle size, and still maintains the initial particle size after being placed at room temperature for 12 months, which shows that the stability is high;

3) the water-based ink prepared by the invention has excellent tinting strength and adhesion fastness, and can be used for surface printing of plastic substrates such as PET, PE/PEVA and the like; contains no or little organic solvent, is not explosive and is suitable for environmental protection; the dryness is controllable and adjustable, and the printing requirement is met; the gloss and the color saturation are similar to those of solvent ink, and the requirement of color reduction is met; the printed matter has no toxic and harmful substances and meets the packaging requirements of food and medicines; good water solubility and re-solubility, easy plate washing, no damage to the plate and accordance with the requirements of printing equipment.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the description is intended to be exemplary only, and is not intended to limit the scope of the present invention.

In order to obtain aqueous ink with stable performance, the invention firstly researches the dispersion performance of the base material, and finds that the water-soluble grinding resin liquid prepared by the invention can be used as the grinding resin to replace the commercial aqueous acrylic resin to obtain the base material for the aqueous ink with smaller particle size and better dispersion performance.

Production example 1

Preparing a water-soluble grinding resin solution:

adding 5.0L of acetone solvent into a 10.0L reactor, adding 40g of hydroxyethyl methacrylate (HEMA), 60g of Glycidyl Methacrylate (GMA), 80g of alginic acid (A), 200g of styrene (S) and 5g of dibenzoyl peroxide (BPO) as initiators under the atmosphere of nitrogen, heating to reflux, stirring and carrying out free radical polymerization for 18-24 h;

and then removing acetone under reduced pressure, evaporating the acetone to dryness, slowly adding deionized water to adjust the non-volatile components to 35 wt%, and finally adjusting the acid value of the resin solution of the system to 168 by adopting 0.2mol/L sodium hydroxide aqueous solution to obtain the quaternary copolymerization water-soluble grinding resin solution.

Example 1

A base material was prepared by using the water-soluble polishing resin liquid prepared in production example 1 as a polishing resin by the following method:

adding 240g of water, 160g of water-soluble grinding resin liquid, 500g of pigment (roller carbon black with the particle size of 1.1-1.2 microns), 50g of dispersing agent (TEGO Dispers 760W) and 3.5g of defoaming agent (TEGO Foamex 810) into a high-speed stirrer in sequence, stirring for about 30 minutes, adding 45g of thinning resin emulsion (HC-8102B type ink resin produced by Sanshui Kongcheng synthetic resin Co., Ltd., Fushan) and dispersing for 1-2 hours by using a high-speed grinder to obtain a base material; the high-speed grinding machine dispersion refers to grinding at room temperature (20-30 ℃) at a rotating speed of 2000-2200 rpm; the grinding medium used in the high-speed grinding machine is zirconia beads with the grain diameter of 0.4-0.6mm, and the ball-material ratio is 4: 1.

Comparative example 1

Compared with example 1, a commercially available aqueous acrylic resin (AZR resin manufactured by Tianjin Atlantic Fine chemical Co., Ltd.) was used in place of the water-soluble polishing resin solution prepared according to the present invention in equal amounts to prepare a base.

Comparative example 2

80g of alginic acid was not added during the preparation of the water-soluble grinding resin solution, and the prepared water-soluble grinding resin solution of terpolymer was used as a grinding resin for a base material, and the rest of the test conditions were the same as those in example 1.

After the base materials prepared in example 1 and comparative examples 1 and 2 are prepared, the base materials are placed at room temperature for 3 days (stored at 20-30 ℃ in a sealed and dark place), the dispersibility of the base materials is measured by adopting an S-3500 laser particle size analyzer, the measurement unit is mum, the invention analyzes and measures the dispersibility of the base materials by using 95% of the maximum particle size (namely more than 95% of all the particle sizes is less than a certain value), and the 95% of the maximum particle size of the base materials prepared in different examples is shown in Table 1:

TABLE 1 particle size of the base prepared in the different examples

Examples	Example 1	Comparative example 1	Comparative example 2
				Particle size/. mu.m	0.9	1.3	1.5

Note: the particle size is 95% or more of the largest particle size.

Test results show that the particle size of the base material prepared by the water-soluble grinding resin liquid as grinding resin is smaller than that of the base material prepared by the commercial water-based acrylic resin; the water-soluble grinding resin liquid prepared by the invention can fully and uniformly disperse the pigment (roller carbon black) and is a good carrier of the pigment; also, in the dispersion process with a high-speed mill, the particle size of the pigment itself is partially ground (average particle size before grinding is 1.1 to 1.2 μm).

The particle sizes of the binders prepared in comparative examples 1 and 2 were 1.3 μm and 1.5 μm, respectively, and the results in example 1 show that the pigment particles can be reduced during milling, but the particle sizes of the binders prepared in the systems of comparative examples 1 and 2 increase rather, indicating that there is a more severe phenomenon of flocculation and sedimentation in comparative examples 1 and 2, resulting in accumulation of pigment particles, thereby showing that the particle size of the milled binder is rather partially increased.

In the grinding process, the solid particle pigment is ground into small particles, the pigment is made to interact with water-soluble resin liquid through resin coating to form a molecular group structure, the particles of the molecular group structure exist in a base material in the form of suspension, and the suspended particles cause flocculation of the suspended particles due to Brownian motion and interaction force (such as hydrogen bonds, Van der Waals force and electrostatic attraction force); the water-soluble grinding resin liquid prepared by the invention plays a role in flocculation resistance and has good wettability to pigments.

Example 2

In the preparation process of the base material, the base material prepared in winter is surprisingly found to have good stability, and the particle size is basically distributed between 0.3 and 0.6 mu m; the base material prepared in summer has poor stability, and the particle size is basically distributed between 1.2 and 1.5 mu m; therefore, the invention carries out systematic optimization on the grinding temperature of the base stock, and the method comprises the following steps:

adding 240g of water, 160g of water-soluble grinding resin liquid, 500g of pigment (roller carbon black with the particle size of 1.1-1.2 microns), 50g of dispersing agent (TEGO Dispers 760W) and 3.5g of defoaming agent (TEGO Foamex 810) into a high-speed stirrer in sequence, stirring for about 30 minutes, adding 45g of thinning resin emulsion (HC-8102B type ink resin produced by Sanshui Kongcheng synthetic resin Co., Ltd., Fushan) and dispersing for 1-2 hours by using a high-speed grinder to obtain a base material; the high-speed grinding machine dispersion refers to grinding at the rotating speed of 2000-2200 r/min at the temperature of 0-40 ℃; the grinding medium used by the high-speed grinding machine is zirconia beads with the particle size of 0.4-0.6mm, and the ball-to-material ratio is 4: 1; the 95% maximum particle size of the base prepared at different temperatures is shown in table 2:

TABLE 2 influence of milling temperature on the particle size of the base

Test results show that the base material ground at low temperature and high temperature has small grain size, so the dispersion stability is high; however, the temperature of about 0 ℃ may be too low, which results in high viscosity of the base material and is not beneficial to grinding of the base material; the overall result shows that the particle size of the base material prepared at 5-10 ℃ is far smaller than that of the base material prepared at high temperature. The milling temperature of the base must be strictly controlled in production. The particle size of the base material prepared at 10 ℃ is 0.38 mu m after the base material is sealed and stored at 30 ℃ for 12 months, which shows that the stability is strong; no flocculation occurred during the standing process.

Production example 2

Preparing a connecting material:

the materials are prepared according to the following mixture ratio: 60 parts by weight of film-forming emulsion (aqueous acrylic emulsion from Green spring, Xiamen, environmental protection materials Co., Ltd.), 25 parts by weight of non-film-forming emulsion (from Pasteur Corp.)

89) 3 parts of cosolvent ethanol, 4 parts of redissolution resin (ethyl cellulose) and 8 parts of water are uniformly stirred and mixed to obtain the connecting material.

Example 3

The base material prepared at 10 ℃ in example 2 and the binder in production example 2 were used as raw materials to prepare the all-water-based ink by the following method:

adding 25 parts by weight of water and 5 parts by weight of water-soluble auxiliary agent (3 parts by weight of ethanol and 2 parts by weight of TEGO Dispers 760W) into a reactor in sequence, stirring for 10-20min, adding 50 parts by weight of connecting material, stirring for 20-30min, and finally adding 20 parts by weight of base material, and stirring at the rotating speed of 600-1000rpm for 1-2 hours to obtain the fully-aqueous ink.

Example 4

The base material prepared at 10 ℃ in example 2 and the binder in preparation example 2 were used as raw materials to prepare the all-water-based ink by the following method:

and sequentially adding 30 parts by weight of water and 5 parts by weight of water-soluble auxiliary agent (3 parts by weight of ethanol and 2 parts by weight of TEGO Dispers 760W) into the reactor, stirring for 10-20min, then adding 55 parts by weight of connecting material, stirring for 20-30min, and finally adding 10 parts by weight of base material, and stirring at the rotating speed of 600-1000rpm for 1-2 hours to obtain the fully-aqueous ink.

The performance of the all-water inks prepared in example 3 and example 4 was tested, and the printing quality of the all-water inks was measured by printing on the surface of the PET plastic film substrate, and the results are shown in Table 3:

TABLE 3 Properties of all-aqueous inks prepared according to the invention

Detecting items	Example 3	Example 4	Detection method
				Water solubility	Mutual solubility at any ratio	Mutual solubility at any ratio	Stirring and mixing
Particle size/. mu.m	0.42	0.39	Laser particle size analyzer
				Viscosity/s	12	13	3 #/Chuan' cup
Incipient wetness mm (30s/25 ℃ C.)	35	32	Scraper instrument
				Coloring power/%)	99	102	GB/T13217.6-2008
Fastness to adhesion/%)	98	97	GB/T13217.7-2009
				VOC	Conform to	Meet with	GB/T26395-2011

Although the embodiments of the present invention have been described in detail, it should be understood that various changes, substitutions, and alterations can be made hereto without departing from the spirit and scope of the invention.

Claims

1. The full-water plastic surface printing ink consists of the following raw materials in percentage by weight: 10-30% of base material, 50-65% of connecting material, 5% of water-soluble auxiliary agent and the balance of water;

the base material comprises the following raw materials in percentage by weight: 15-20% of water-soluble grinding resin liquid; 40-65% of pigment; 4-6% of a dispersant; 0.3 to 0.4 percent of defoaming agent; diluting the resin emulsion: 4 to 5 percent; the balance of water; the pigment is roller carbon black;

the connecting material comprises the following raw materials in percentage by weight: 60-70% of film-forming emulsion, 25-30% of non-film-forming emulsion, 3-5% of cosolvent, 3-5% of redissolving resin and the balance of water;

adding acetone serving as a solvent into a reactor, adding 40 parts by weight of hydroxyethyl methacrylate, 60 parts by weight of glycidyl methacrylate, 80 parts by weight of alginic acid, 200 parts by weight of styrene and 5 parts by weight of dibenzoyl peroxide under the atmosphere of nitrogen, stirring and refluxing for free radical polymerization reaction for 18-24h, then removing acetone under reduced pressure, slowly adding deionized water to adjust the non-volatile components to 30-40wt%, and finally adjusting the acid value of the resin liquid of the system to 160-180 ℃ by adopting 0.2mol/L sodium hydroxide aqueous solution to obtain a quaternary copolymerization water-soluble grinding resin liquid;

the preparation method of the base material comprises the following steps: weighing water, water-soluble grinding resin liquid, pigment, dispersing agent and defoaming agent according to a formula ratio, sequentially adding the mixture, stirring the mixture for 30 minutes by using a high-speed stirrer, adding diluted resin emulsion, and dispersing the mixture for 1 to 2 hours by using a high-speed grinder to obtain a base material; the high-speed grinding machine dispersion refers to grinding at the rotating speed of 2000-2200 rpm at the temperature of 5-10 ℃; the grinding medium used by the high-speed grinding machine is zirconia balls with the grain diameter of 0.4-0.6mm, and the ball-to-material ratio is 4: 1; the film-forming emulsion is acrylic film-forming emulsion; the non-film-forming emulsion is acrylic non-film-forming emulsion produced by BASF company, of which the type is JONCRYL 89 or JONCRYL 90.

2. The fully aqueous plastic overprint ink according to claim 1, characterized in that: the water-soluble auxiliary agent is a water-soluble dispersing agent, a defoaming agent, a color tone regulator, a fluidity regulator or a drying regulator.

3. The fully aqueous plastic overprint ink according to claim 1, characterized in that: the diluting resin emulsion is HC-8102B type ink resin produced by three-water double-honest synthetic resin Co.

4. The fully aqueous plastic overprint ink according to claim 1, characterized in that: the redissolved resin is a low molecular weight solvent type redissolved resin, and the low molecular weight solvent type redissolved resin is selected from ethyl cellulose, hydroxyl modified binary vinyl chloride-vinyl acetate copolymer, chlorinated polyolefin or styrene acrylic acid; the low molecular weight solvent is selected from alcohol, ester or ether.

5. The fully aqueous plastic overprint ink according to claim 1, characterized in that: the cosolvent is ethanol, isopropanol, acetone, ethylene glycol or glycerol.