CN113480712A

CN113480712A - Dispersing agent and photocuring 3D printing ink

Info

Publication number: CN113480712A
Application number: CN202110818639.0A
Authority: CN
Inventors: 庄皓云
Original assignee: Kunshan Jiucan New Material Technology Co ltd
Current assignee: Kunshan Jiucan New Material Technology Co ltd
Priority date: 2021-07-20
Filing date: 2021-07-20
Publication date: 2021-10-08

Abstract

The invention discloses a dispersing agent and photocuring 3D printing ink, and belongs to the technical field of dispersing agents. Raw materials of the dispersing agent comprise polyhydric alcohol, isocyanate, hydroxy acid, hydroxy alkenoic acid ester, monohydric alcohol and the like, the NCO content in the system is controlled by the polymerization reaction of the isocyanate and the polyhydric alcohol and the hydroxy acid, the hydroxy alkenoic acid ester and the monohydric alcohol until the NCO value in the dispersing agent is less than 0.1; the dispersant obtained by the invention can directly replace a commercial dispersant to disperse various organic or inorganic pigments and prepare various inks. The photocuring 3D printing ink prepared by using the dispersing agent has excellent dispersing performance: the dispersed particle size is less than 5 mu m, the viscosity is 10000-; the comprehensive performance is good: the coating film gloss can be more than 95 measured at an angle of 60 degrees, the covering power is more than 85 percent, and the pencil hardness is more than HB.

Description

Dispersing agent and photocuring 3D printing ink

Technical Field

The invention belongs to the technical field of dispersing agents, can be applied to a 3D printing technology, and particularly relates to a dispersing agent and photocuring 3D printing ink.

Background

The problem of dispersion of solid particles, organic or inorganic, in a medium is often involved in the production of pigments, coatings, inks, filled plastics. Since the dispersibility of these solid particles in a medium affects not only the yield, energy consumption and raw material consumption of the product but also the final quality of the product, such as gloss, color strength, tensile strength, etc., a dispersant is used in the above production process in order to disperse the solid particles well in the medium.

The common simpler method for the colored 3D printing ink is to directly add the commercially available color paste into the ink and directly add the pigment toner into the ink for stirring and dispersing, wherein the former is limited by the fact that the composition of the commercially available color paste cannot be known, and the former needs to be tested for many times, and the latter is easy to have the phenomenon of uneven dispersion, and is easy to generate the conditions of sedimentation, agglomeration and the like.

When the medium in which the solid particles are located is a non-aqueous system, a polyurethane dispersant is typically used. The molecular structure of polyurethane dispersants generally includes two parts: one part is an anchoring group, common polyamine, polyalcohol, polyether and the like are available, and the anchoring group can be tightly combined on the surface of the particles through the actions of ion pairs, hydrogen bonds, van der waals force and the like to prevent the hyperdispersant from being desorbed; the other part is a solvation chain, which is commonly polyester, polyether, polyolefin, polyacrylate and the like, and the solvation chain is a polymer chain capable of being solvated by a medium, and can play a role in dispersing and stabilizing particles through a steric hindrance effect.

The terminal groups of the solvating chains of existing dispersants, such as polyesters, polyethers, etc., are usually reactive groups. The reactive groups can be oxidized by oxygen in the air to form new groups, and the new groups can continue to react with other reactive groups, so that the structure of the dispersing agent is changed, and the performance is changed due to the structural change. This is not only disadvantageous in storage of the dispersant, but also causes gelation, sedimentation, etc. of the dispersant due to changes in the performance of the dispersant during production and use.

In the chinese patent application CN102964920A (an ink for ceramic inkjet printing and a preparation method thereof), the dispersant used in the ink is a high molecular weight polyurethane dispersant or a high molecular weight polyacrylate dispersant, and the molecular weight of the dispersant is 1000-10000, but the dispersant can only be used in a part of commercial products, and cannot be widely used in the dispersion of various organic or inorganic pigments in the ink.

Disclosure of Invention

The invention aims to provide a dispersing agent and a photocuring 3D printing ink to solve the technical problems mentioned in the background technology.

In order to achieve the purpose, the invention discloses a dispersing agent which comprises the following raw materials in parts by weight:

further, the equivalent ratio of the polyol to the isocyanate is 1: 3. Preferably, the equivalent ratio of polyol, isocyanate, hydroxy acid, hydroxy alkenoate and monoalcohol is 1.0:3.0:0.1:1.0: 0.5.

Wherein, the polymerization inhibitor of the invention adopts hydroquinone monomethyl ether.

Further, the choice of the polyol depends on the molecular weight of the final product and the product function, and the dispersant applied to the photo-curing 3D printing ink of the present invention is selected from polyols having an anchor group for the pigment and photocurable polyols having C ═ C bonds, preferably having a molecular weight of between 500 and 3000. One or a mixture of more of polypropylene glycol, polyether diol, polytetrahydrofuran diol, polycaprolactone diol, polycarbonate diol and polyester diol is preferred; preferably one or a mixture of more of polypropylene glycol, polyether diol, polytetrahydrofuran diol, polycaprolactone diol and polyester diol.

Further, the isocyanate is selected from compounds having aliphatically, cycloaliphatically, araliphatically and/or aromatically bonded isocyanate groups having a molecular weight in the range of 140-400g/mol, such as toluene diisocyanate, 1, 4-diisocyanatobutane, 1, 6-diisocyanatohexane (HDI), 2-methyl-1, 5-diisocyanatopentane, 1, 5-diisocyanato-2, 2-dimethylpentane, 2, 4-trimethyl-1, 6-diisocyanatohexane, 2,4, 4-trimethyl-1, 6-diisocyanatohexane, 1, 10-diisocyanatodecane, 1, 3-diisocyanatocyclohexane, 1, 4-diisocyanatocyclohexane, 1, 3-bis (isocyanatomethyl) cyclohexane and 1, 4-bis (isocyanatomethyl) cyclohexane, 1-isocyanato-3, 3, 5-trimethyl-5-isocyanatomethylcyclohexane, isophorone diisocyanate (IPDI), 2' -diisocyanatodicyclohexylmethane, 2,4' -diisocyanatodicyclohexylmethane, 4' -diisocyanatodicyclohexylmethane (H12MDI), 1-isocyanato-1-methyl-4 (3) isocyanatomethylcyclohexane, bis (isocyanatomethyl) norbornane, 1, 3-bis- (2-isocyanatoprop-2-yl) benzene, 1, 4-bis- (2-isocyanatoprop-2-yl) benzene (TMXDI), One or more of 2, 4-diisocyanatotoluene, 2, 6-diisocyanatotoluene (TDI), 2,4 '-diisocyanatodiphenylmethane, 4' -diisocyanatodiphenylmethane (MDI) and 1, 5-diisocyanatonaphthalene; isophorone diisocyanate is preferred.

Further, the hydroxy acid is selected from dimethylolpropionic acid, dimethylolbutyric acid or 2, 3-dihydroxy-3-methylpentanoic acid; dimethylolpropionic acid is preferred. Wherein the hydroxy acid contains an anchoring group.

Further, the hydroxy alkenoic acid ester is selected from hydroxyethyl acrylate, 2-hydroxyethyl methyl acrylate or hydroxyethyl methacrylate; preferably hydroxyethyl acrylate. Wherein the hydroxy alkenoic acid ester contains unsaturated double bonds.

Further, the monohydric alcohol is selected from methanol, ethanol, propanol, butanol or hexanol; methanol is preferred.

Further, in the raw materials for preparing the dispersant, since the final product is a product applied to 3D photo-curing printing, the diluent is selected from organic solvents having a photo-curable C ═ C group, and 1, 6-hexanediol diacrylate (HDDA), dipropylene glycol diacrylate (DPGDA), tripropylene glycol diacrylate (TPGDA), isobornyl acrylate (IBOA), isobornyl methacrylate (IBOMA), isooctyl acrylate (EHA), isodecyl acrylate (ISODA), Lauryl Methacrylate (LMA), dipropylene glycol diacrylate (DPGDA), tricyclodecane dimethanol diacrylate (dcpd da), trimethylolpropane triacrylate (TMPTA), ethoxylated trimethylolpropane triacrylate (ETPTA), trimethylolpropane triacrylate (ptma), pentaerythritol triacrylate (PETA), and mixtures thereof, One or more of pentaerythritol tetraacrylate (PET4A) and dipentaerythritol hexaacrylate (DPHA) is preferably tripropylene glycol diacrylate or trimethylolpropane triacrylate.

Further, the catalyst is not particularly limited, and may be selected from a tin-based catalyst, a lead-based catalyst, an amine-based catalyst, or a diazabicycloalkene-based catalyst; the tin-based catalyst includes trimethyltin laurate and butyltin dilaurate, the lead-based catalyst includes lead octoate, and the amine-based catalyst includes triethylamine, N-ethylmorpholine, or triethyldiamine; from the viewpoint of reactivity, dibutyltin dilaurate is preferable.

Still further, the NCO value of the dispersant is less than 0.1.

The invention also claims a preparation method of the dispersing agent, which comprises the following steps:

(1) adding a solvent, polyhydric alcohol and a polymerization inhibitor into a reaction container, heating to 50-100 ℃, and stirring until the solid is completely dissolved;

(2) introducing nitrogen into a reaction vessel, adding isocyanate and a catalyst, reacting at 50-100 ℃, and then sequentially adding hydroxy acid, hydroxy alkenoic acid ester and monohydric alcohol for continuous reaction.

Further, detecting the content of NCO groups of the reaction product in the step (2) in real time, and adding hydroxy acid and hydroxy alkenoic acid ester into the reaction vessel to continue the reaction when the NCO value is less than 1.35; when the NCO value is less than 0.3, a monohydric alcohol is added to the reaction vessel until the NCO value in the reaction product is less than 0.1.

In the process of preparing the dispersing agent by chemical reaction, the content of NCO needs to be controlled, if the NCO value is more than 0.1, the product is easy to hydrolyze, so the performance of the product is unstable, and when the NCO value is less than 0.1, the performance of the product is stable.

In the present invention, the polyurethane is formed by reacting a polyisocyanate with a polyol. The molecular weight of the final polyurethane can be controlled by using a monohydric alcohol as the end-cap. The capping group prevents the polyurethane from increasing in molecular weight by terminating (i.e., 'capping') the polymerizable end groups of the polyurethane. Suitable monoalcohols for the partially end-capped polyurethane prepolymers are methanol, ethanol, propanol, butanol or hexanol.

The reaction process for synthesizing the dispersing agent comprises the following steps:

wherein the A group has the structure

R1-R4 are aromatic or long chain of C1-C5.

The polyurethane is obtained through the polymerization reaction of isocyanate and polyol, and the polymerization reaction of the isocyanate and the polyol is carried out to obtain the polyurethane with hydroxyl and carboxylic groups, so that the polyester type hyperdispersant is obtained. According to the invention, before the synthesis reaction of the hyper-dispersant is terminated, the isocyanic acid is adopted to react with the hydroxyl at one end of the solvating chain to generate the polyurethane with stable performance, so that the hydroxyl of the solvating chain is changed into the polyurethane with stable performance from the isocyanate with reactivity, and the deterioration phenomena of gel, sedimentation and the like of the dispersant caused by the isocyanate group as a group with reactivity are avoided.

The invention also claims a photocuring 3D printing ink which uses the dispersant obtained by the preparation method.

The photocuring 3D printing ink comprises the following components in percentage by mass:

wherein the reactive resin is epoxy acrylic resin. The diluent monomer is a mixture of tripropylene glycol diacrylate and trimethylolpropane triacrylate; fillers include titanium dioxide, calcium carbonate and thickeners; the photoinitiator is a mixture of Benzophenone (BP), 1-hydroxycyclohexyl phenyl ketone (PI-184) and 2-methyl-1- [4- (methylthio) phenyl ] -2- (4-morpholinyl) -1-acetone (PI-907); the additives include stabilizers, defoamers, and leveling agents.

The preparation method of the photocuring 3D printing ink comprises the following steps: uniformly mixing the dispersant, the filler and part of the diluent monomer, rolling and dispersing the mixture into color paste, then sequentially adding the reaction resin, the rest of the diluent monomer, the photoinitiator and the additive, and uniformly mixing and stirring the mixture.

Compared with the prior art, the dispersing agent and the photocuring 3D printing ink have the following advantages:

(1) the dispersant is a polyurethane dispersant, is used in 3D printing ink, solves the problem of dispersion of organic or inorganic solid particles in a medium, has excellent dispersion performance, can ensure that the dispersion particle size is less than 5 mu m, the viscosity is 10000-20000cps, and the variation of the viscosity is less than 200cps after the viscosity is stored for 30 days at 60 ℃, so the viscosity stability is good.

(2) The dispersant is obtained by the polymerization reaction of isocyanic acid and polyol, and the termination reaction is carried out by adopting monohydric alcohol to carry out end capping reaction, so that polyurethane with stable performance is obtained, and the deterioration phenomena of gel, sedimentation and the like in the use process of the dispersant can be avoided.

(3) Compared with the commercially available dispersant, when the dispersant is used for preparing the photocuring 3D printing ink, the preparation process is simple, and the ink has good comprehensive performance: the coating film gloss can be more than 95 measured at an angle of 60 degrees, the covering power is more than 85 percent, and the pencil hardness is more than HB.

Detailed Description

The technical solution of the present invention will be described in detail by the following specific examples.

Example 1

Preparing a dispersing agent F1, comprising the following steps:

(1) adding 14 parts of polycaprolactone diol, 7 parts of polypropylene glycol and 69 parts of tripropylene glycol diacrylate into a reaction vessel, mixing and heating to 70 ℃, introducing nitrogen after solid components are completely dissolved, then adding 0.03 part of dibutyltin dilaurate and 7 parts of isophorone diisocyanate, and reacting at 70 ℃;

(2) after reacting for 3 hours, detecting the NCO content, and when the NCO content is less than 1.35, adding 0.9 part of dimethylolpropionic acid, 1.9 parts of hydroxyethyl acrylate and 0.07 part of hydroquinone monomethyl ether to react at 70 ℃;

(3) after reacting for 3 hours, detecting the NCO content, when the NCO content is less than 0.3, cooling to 50 ℃, and adding 0.5 part of methanol for reaction;

(4) after reacting for 30 minutes, detecting the content of NCO, and obtaining the dispersing agent when the content of NCO is less than 0.1.

The dispersant obtained by this process is designated as F1.

Example 2

Preparing a dispersing agent F2, comprising the following steps:

(1) adding 14 parts of polycaprolactone diol, 7 parts of polyethylene glycol and 71 parts of 1, 6-hexanediol diacrylate into a reaction vessel, mixing and heating to 70 ℃, introducing nitrogen after the solid component is completely dissolved, then adding 0.03 part of dibutyltin dilaurate and 6 parts of toluene diisocyanate, and reacting at 70 ℃;

(2) after reacting for 3 hours, detecting the NCO content, and when the NCO content is less than 1.35, adding 0.9 part of dimethylolpropionic acid, 1.9 parts of 2-hydroxyethyl methyl acrylate and 0.07 part of hydroquinone monomethyl ether to react at 70 ℃;

The dispersant obtained by this process is designated as F2.

A commercially available dispersant (trade mark BYK161), and dispersant F1 and dispersant F2 obtained in example 1 and example 2, respectively, were used as dispersant raw materials to prepare 3D printing inks as shown in example 3, example 4, and example 5.

Wherein the thickener in the filler is selected

200 or Evonik degussaAE 200.

The stabilizer in the additive is Eversorb 72 UV-329.

The defoaming agent is a polymer defoaming agent without organic silicon, and the trade mark is BYK051 or BYK 052.

The flattening agent selects BYK306 and BYK 333.

Example 3

Preparing 3D printing ink, comprising the following steps:

according to the proportion of table 1, uniformly mixing a dispersing agent, a filling agent and 1/4 parts of a diluent monomer, rolling and dispersing the mixture into a color paste by using a three-roller rolling press, then sequentially adding a reaction type resin, the rest of the diluent monomer, a photoinitiator and an additive, and uniformly mixing and stirring to obtain the 3D printing ink, which is marked as S1.

Table 1 raw material composition of 3D printing ink S1 in example 3

Example 4

Preparing 3D printing ink, comprising the following steps:

according to the proportion shown in the table 2, a dispersing agent, a filling agent and 1/4 parts of a diluting monomer are uniformly mixed, then the mixture is rolled and dispersed into color paste by a three-roller rolling press, then a reaction type resin, the rest of the diluting monomer, a photo initiator and an additive are sequentially added, and the mixture is uniformly mixed and stirred to obtain the 3D printing ink which is marked as S2.

Table 2 raw material composition of 3D printing ink S2 in example 4

Example 5

Preparing 3D printing ink, comprising the following steps:

according to the proportion shown in the table 3, the dispersing agent, the filler and 1/4 parts of the diluent monomer are uniformly mixed, then the mixture is rolled and dispersed into color paste by a three-roller rolling press, then the reaction resin, the rest of the diluent monomer, the photoinitiator and the additive are sequentially added, and the mixture is uniformly mixed and stirred to obtain the 3D printing ink which is marked as S3.

Table 3 raw material composition of 3D printing ink S3 in example 3

And (3) performance testing:

the 3D printing inks S1 to S3 obtained in examples 3 to 5 were subjected to performance tests, and after being dried by UV Lamp UV irradiation, the 3D printing ink coating layer having a dried surface was subjected to performance tests, and the test results are shown in table 4.

TABLE 43 Performance test results for printed inks

As can be seen from Table 4, the 3D printing ink prepared by the dispersant obtained by the method has the advantages of low respective performances of , and is superior to the 3D printing ink prepared by the commercial dispersant.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like made within the design concept of the present invention should be included in the scope of the present invention.

Claims

1. A dispersant, characterized by: the raw materials comprise the following components in parts by weight:

2. the dispersant of claim 1, wherein: the equivalent ratio of the polyol, isocyanate, hydroxy acid, hydroxy alkenoic acid ester and monohydric alcohol is 1.0:3.0:0.1:1.0: 0.5.

3. The dispersant of claim 1, wherein: the polyalcohol is one or more of polypropylene glycol, polyether diol, polytetrahydrofuran diol, polycaprolactone diol, polycarbonate diol and polyester diol.

4. The dispersant of claim 1, wherein: the molecular weight of the isocyanates is 140-400g/mol and the isocyanates are compounds having aliphatically, cycloaliphatically, araliphatically and/or aromatically bonded isocyanate groups.

5. The dispersant of claim 4, wherein: the isocyanate is selected from the group consisting of toluene diisocyanate, 1, 4-diisocyanatobutane, 1, 6-diisocyanatohexane, 2-methyl-1, 5-diisocyanatopentane, 1, 5-diisocyanato-2, 2-dimethylpentane, 2, 4-trimethyl-1, 6-diisocyanatohexane, 2,4, 4-trimethyl-1, 6-diisocyanatohexane, 1, 10-diisocyanatodecane, 1, 3-diisocyanatocyclohexane, 1, 4-diisocyanatocyclohexane, 1, 3-bis (isocyanatomethyl) cyclohexane, 1, 4-bis (isocyanatomethyl) cyclohexane, 1-isocyanato-3, 5-trimethyl-5-isocyanatomethylcyclohexane, isophorone diisocyanate, 2 '-diisocyanatodicyclohexylmethane, 2,4' -diisocyanatodicyclohexylmethane, 4 '-diisocyanatodicyclohexylmethane, 1-isocyanato-1-methyl-4 (3) isocyanatomethylcyclohexane, bis (isocyanatomethyl) norbornane, 1, 3-bis- (2-isocyanatoprop-2-yl) benzene, 1, 4-bis- (2-isocyanatoprop-2-yl) benzene, 2, 4-diisocyanatotoluene, 2, 6-diisocyanatotoluene, 2,4' -diisocyanatodiphenylmethane, isophorone diisocyanate, 2 '-diisocyanatodiphenylmethane, 2,4' -diisocyanatodiphenylmethane, mixtures thereof, and mixtures thereof, One or a mixture of more of 4,4' -diisocyanatodiphenylmethane and 1, 5-diisocyanatonaphthalene; isophorone diisocyanate is preferred.

6. The dispersant of claim 1, wherein: the hydroxy acid is selected from dimethylolpropionic acid, dimethylolbutyric acid or 2, 3-dihydroxy-3-methylpentanoic acid; dimethylolpropionic acid is preferred.

7. The dispersant of claim 1, wherein: the hydroxy olefine acid ester is selected from hydroxyethyl acrylate, 2-hydroxyethyl methyl acrylate or hydroxyethyl methacrylate; preferably hydroxyethyl acrylate.

8. The dispersant of claim 1, wherein: the monohydric alcohol is selected from methanol, ethanol, propanol, butanol or hexanol; methanol is preferred.

9. The dispersant of claim 1, wherein: the diluent is an organic solvent with C ═ C groups, and is selected from one or a mixture of more of 1, 6-hexanediol diacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, isobornyl acrylate, isobornyl methacrylate, isooctyl acrylate, isodecyl acrylate, lauryl methacrylate, dipropylene glycol diacrylate, tricyclodecane dimethanol diacrylate, trimethylolpropane triacrylate, ethoxylated trimethylolpropane triacrylate, pentaerythritol tetraacrylate or dipentaerythritol hexaacrylate; preferably tripropylene glycol diacrylate or trimethylolpropane triacrylate.

10. The dispersant of claim 1, wherein: the catalyst is selected from a tin catalyst, a lead catalyst, an amine catalyst or a diazabicyclo carbene catalyst; the tin-based catalyst includes trimethyltin laurate and butyltin dilaurate, the lead-based catalyst includes lead octoate, and the amine-based catalyst includes triethylamine, N-ethylmorpholine, or triethyldiamine; dibutyltin dilaurate is preferred.

11. The dispersant of claim 1, wherein: the NCO value in the dispersant is less than 0.1.

12. A method for preparing a dispersant as claimed in any one of claims 1 to 11 wherein: the method comprises the following steps:

(1) adding a diluent, polyhydric alcohol and a polymerization inhibitor into a reaction container, heating to 50-100 ℃, and stirring until the solid is completely dissolved;

13. The method of claim 12, wherein: detecting the content of NCO groups of the reaction product in the step (2) in real time, and adding hydroxy acid and hydroxy alkenoic acid ester into the reaction vessel to continue the reaction when the NCO value is less than 1.35; when the NCO value is less than 0.3, a monohydric alcohol is added to the reaction vessel until the NCO value in the reaction product is less than 0.1.

14. A photocurable 3D printing ink using the dispersant obtained by the production method according to claim 13.