CN114015280A

CN114015280A - Low-temperature curing gravure ink suitable for PET (polyethylene terephthalate) and PI (polyimide) substrates and preparation method thereof

Info

Publication number: CN114015280A
Application number: CN202111502403.2A
Authority: CN
Inventors: 缪云飞; 鲁斌; 汪小峰; 徐宏; 花魁昌; 欧阳旭频
Original assignee: Suzhou Beiely Polymer Materials Co ltd
Current assignee: Suzhou Beiely Polymer Materials Co ltd
Priority date: 2021-12-10
Filing date: 2021-12-10
Publication date: 2022-02-08

Abstract

The invention discloses a low-temperature curing gravure ink suitable for PET and PI substrates and a preparation method thereof, wherein special modified polyester resin with smaller molecular weight is used as main resin matched with polyurethane resin which can be perfectly fused with the main resin, solvent selection and a dispersing agent are combined, the wettability of the resin to carbon black is increased, the color development of the ink is improved, the adhesive force to the PET and PI substrates after curing and film forming is excellent, the matched polyurethane resin is used as the main resin for grinding carbon black, the effect of the matched dispersing agent on the effect of grinding the carbon black is very good, and a certain promotion effect on the improvement of the adhesive force is achieved; the ink layer formed after the reaction of the resin and the isocyanate curing agent is compact and firm, has excellent alcohol resistance, and also has certain effects of resisting the wiping of ethyl ester and butanone; the ink has high reaction speed and good solvent release performance, so that the effect of quick surface drying and no back adhesion can be realized at a lower temperature (80-100 ℃).

Description

Low-temperature curing gravure ink suitable for PET (polyethylene terephthalate) and PI (polyimide) substrates and preparation method thereof

Technical Field

The invention belongs to an ink technology, and particularly relates to a low-temperature curing gravure ink suitable for PET and PI substrates and a preparation method thereof.

Background

The film materials used for battery packaging, electronic tapes, electronic nameplates, electronic labels, special packaging and other occasions are generally PET (polyethylene terephthalate) materials and PI (polyimide) materials, and some film materials use BOPP (polypropylene films), PVC (polyvinyl chloride films) and TPU (polyurethane) films, wherein the PET materials have more usage amount due to higher cost performance ratio and PI materials and excellent performance thereof, and the thickness of the film used can be thinner along with the gradual updating of products, and meanwhile, due to the competitive power, energy saving and cost reduction are inevitable trends, so that the ink coated on the PET and PI materials is also developed in the direction of low-temperature curing, and for coating enterprises, no ink is compatible with other excellent performance (such as scratch resistance, low cost performance, high adhesion strength, high adhesion and the like) on the PET and PI materials at the same time at present, Alcohol resistance, ethyl ester resistance, fingerprint resistance, excellent color difference and the like).

The existing black ink for gravure coating belongs to a polyurethane system which has the best adhesive force on a PET/PI material, but the polyurethane system ink on the market is usually used as a primer, and particularly, the effects of alcohol resistance, scratch resistance, fingerprint resistance and the like of the polyurethane system ink are relatively poor, so that the polyurethane system ink is not suitable as a top coating; epoxy system ink is less used for black ink in the market, the adhesive force of the epoxy system ink on a PET/PI material is poor, the curing temperature is high, and the use condition is harsh; the acrylic acid system has a very good low-temperature curing effect, but the adhesive force is generally poor, and some special modified acrylic resins in the market at present can realize excellent adhesive force on a PET material, but when the acrylic acid system is used for black ink, the adhesive force of the ink can be rapidly reduced along with the addition of carbon black, and the covering and the adhesion cannot be realized; the common polyester system gravure coating ink has a plurality of types on the market, but most of the common polyester system gravure coating inks have good adhesive force on a PET material, the PI material has poor adhesive force, and the black ink has poor covering performance, the gravure black ink is required to realize excellent covering performance, the selection and the addition amount of carbon black are the most significant influences except the selection of a dispersing agent and the matching of resin, and the excellent covering effect can be achieved only when the addition amount of the carbon black accounts for about 15 percent of the whole ink.

Disclosure of Invention

According to the invention, the special modified polyester resin (as main body resin) with a smaller molecular weight is matched with the polyurethane resin, the carbon black and the auxiliary agent, and all components are perfectly fused, wherein the special modified polyester resin is mainly hyperbranched modified polyester, so that the wettability of the resin to the carbon black is increased, the color development of the ink is improved, meanwhile, due to the hyperbranched modification factor and the matching of epoxy polyurethane and a curing agent, the adhesive force of the ink to PET and PI base materials after curing and film forming is excellent, the matched polyurethane resin is used as the main body resin for grinding the carbon black, the effect of matching with Lu Ruo Rui 20000 dispersing agent on the carbon black grinding effect is very good, and meanwhile, the existence of the polyurethane resin has a certain promotion effect on the promotion of the adhesive force; the hyperbranched modified polyester resin with small molecular weight has high hydroxyl content, and an ink layer formed after the reaction with an isocyanate curing agent is compact and firm, and has excellent alcohol resistance and a certain effect of resisting the wiping of ethyl ester and butanone by matching with polyurethane resin and an auxiliary agent; the ink system has higher reaction speed and good solvent release performance, so that the effect of quick surface drying and no back adhesion can be realized at lower temperature (80-100 ℃).

The invention adopts the following technical scheme:

the low-temperature curing gravure ink suitable for PET and PI substrates comprises hyperbranched modified polyester resin, epoxy modified polyurethane resin, a solvent, a dispersing agent, carbon black, a delustering filler, an anti-settling additive, an auxiliary agent and a curing agent.

Preferably, the low-temperature curing gravure ink suitable for PET and PI substrates consists of the following raw materials in parts by weight:

the hyperbranched polyester resin used in the invention is one or more of CL250, CL150 and CL151 of a vast sea resin and 5064-R of Changxing chemistry, the molecular weight of the resin is usually not more than 6000, the resin has higher hydroxyl content, the hydroxyl value is usually 50 to 100, the ink can be easily made into a high-solid low-viscosity product under the condition of smaller molecular weight, and 50 percent of solid content is generally selected as a standard; the Tg point of the resin is usually high and can reach more than 50 ℃, a compact and hard film layer is formed after a large amount of hydroxyl groups react with isocyanate, and the epoxy modified polyurethane resin has excellent alcohol resistance and solvent resistance, and meanwhile, due to the flexibility of a molecular chain segment of the polyester resin, the film has excellent rubbing resistance even on a very thin PET (4 mu m) material;

the epoxy modified polyurethane resin used in the invention is one or more of B-8556-30, AG-1141-1, PU40 and PU205 of Lathyrus chinensis Baill resin, the solid content of the resin is about 30% due to the characteristics of the molecular structure of the polyurethane resin, and the polyurethane resin has good wettability to carbon black particles, so when the epoxy modified polyurethane resin is used for grinding carbon black after being matched with a dispersing agent and a plurality of solvents, the epoxy modified polyurethane resin shows excellent grinding effect and carbon black dispersing effect; the polyurethane resin has excellent adhesive force to PET/PI materials, forms transparent clear liquid with good compatibility with hyperbranched modified polyester resin under the combined action of a plurality of solvents, and the liquid is used as a main binder of the ink, thereby providing excellent physical and chemical properties after the ink forms a film, such as excellent adhesive force, interlayer adhesive force and chemical resistance;

the dispersant used in the invention is one or more of BYK-163, Luborun 20000 and Luborun 27000, the dispersant mainly acts to disperse carbon black particles, so that the carbon black particles can be uniformly dispersed in a resin system to form stable black fluid, and due to the intermolecular interface effect of the dispersant, the carbon black is not easy to agglomerate in the resin system, so that the ink is not easy to generate adverse phenomena such as coarseness return, precipitation and the like; the used carbon black is one or more of Columbia 1200, Mitsubishi MA11, Kabot S90B and ZG600T of Zhihua new material, the carbon black which is easy to disperse and high in covering can provide excellent covering effect for the ink by matching with a proper dispersant, so that the black color of a dry film coating is greatly improved, and in addition, the proper dispersant and the carbon black are combined, so that the grinding and dispersing process is easier, the production process is simplified, and the excellent contribution can be made in the aspect of reducing the production cost; the extinction filler is mainly fumed silica powder with the particle size of 2-3 mu m, the powder with too large particles has strong extinction capability, but the surface of a coating film is rough and has low fineness, the powder with too small particles has poor extinction capability, and the proper extinction effect can be achieved only by adding more powder, but the excessive addition of the fumed silica has very high oil absorption value, so that the overall adhesive force of the ink is reduced, the selection of the extinction filler with the proper particle size is also particularly important, the addition of the extinction filler enables the ink coating to become glossy, and besides the matte appearance effect, the surface drying effect of the ink layer can be promoted; the used solvent is one or more of ethyl acetate, butanone, acetone and methyl isobutyl ketone, the solvent is matched for use, so that the solubility of the solvent to resin is optimal, the resin formula and the dispersing agent are combined, the stability of the ink can be improved, the storage time of the ink can be prolonged, the volatilization stage of the solvent in the low-temperature curing process of the ink is easy, and the method has an extremely important promotion effect on the surface drying effect of the ink; preferably, the solvent is ethyl acetate, butanone and methyl isobutyl ketone; the anti-settling additive is one or more of white carbon black, polyethylene wax slurry and BYK-410 anti-settling additive, the anti-settling additive is mainly used for preventing the carbon black and the extinction filler from settling, particularly for the black ink with low viscosity, the covering performance of an ink coating is poor after particles are settled, and the anti-settling additive, the dispersing agent and the solvent are used for regulating the compatibility of the carbon black and the resin, so that the low-viscosity ink has a good covering effect.

The auxiliary agent used in the invention is an adhesion promoter which mainly comprises one or more of silane coupling agent, titanate coupling agent and organic siloxane, the adhesion promoter mainly has the function of ensuring the problem of adhesion reduction caused by the addition of a large amount of carbon black and matting filler, and the adhesion of the ink is improved under the action of the resin curing agent, preferably 1-5 parts; in addition, the used auxiliary agent is one or more of an organic tin drier and an organic amine drier, and the drier is used for promoting the reaction speed of hydroxyl in the ink in the reaction with isocyanate so as to further improve the curing efficiency and the curing completion degree of the ink, and preferably 0.1-0.5 part. The combined action of the adhesion promoter and the drier has a certain guarantee effect on the adhesion of the ink on materials, and the resin system is combined, so that the ink has good adhesion, and the chemical resistance is improved.

The carbon black selected in the invention can be pretreated by using a dispersant and a solvent in advance, the carbon slurry obtained by pretreatment is uniformly and stably dispersed, and the grinding times and the grinding time required after the carbon black is mixed with other materials are greatly shortened, so that the production cost of the whole printing ink is reduced.

The advantages and effects are as follows:

compared with the prior art, compared with the incompatibility of common polyester resin and polyurethane resin, the selected low-molecular-weight hyperbranched modified polyester resin and epoxy polyurethane resin have better compatibility, and the curing agent is combined under the dissolution of a plurality of solvents, so that the resistance and the adhesive force characteristics of different resins can be mixed, the excellent adhesive force characteristics on a PET substrate and a PI substrate are realized, and the ink can be subjected to low-temperature curing reaction and form a powerful adhesive effect through the higher Tg point and the higher dryness and smoothness of the resin, so that the low-temperature curing characteristic is realized; in addition, compared with the traditional black covering ink, the black covering ink has higher covering performance, and also has the characteristics of more excellent alcohol resistance, butanone resistance and ethyl ester resistance, and meanwhile, the dry ink film has higher surface dyne value, so that the adhesion of the matte oil capable of improving the color difference value on the dry ink film is very excellent, and the phenomenon of bottom biting and bottom floating cannot occur.

Drawings

FIG. 1 is a conventional PET film material;

FIG. 2 is a conventional PI film material;

FIG. 3 is a diagram of the covering effect;

FIG. 4 is a graph of the effect of 50 alcohol wipes;

fig. 5 is a graph showing the effect of butanone-resistance wiping 30 times.

Detailed Description

The low-temperature curing gravure ink suitable for PET and PI substrates consists of hyperbranched modified polyester resin, epoxy modified polyurethane resin, a solvent, a dispersant, carbon black, a delustering filler, an anti-settling additive, an auxiliary agent and a curing agent, wherein the curing agent is mixed before coating. All the raw materials of the invention are commercial products, the specific preparation operation and the testing method are conventional technologies, the creativity of the invention lies in the selection of the formula and the combination of the components, and each weight part is 100 g; the matting filler is fumed silica powder with the particle size of 2-3 mu m.

Example one

1. Dispersing a dispersing agent and a solvent (20 wt% of each of the three types) according to a ratio, adding carbon black, then performing dispersing and grinding processes, and storing the ground carbon slurry for later use;

2. mixing resin, solvent (60 wt% of each of the three), extinction filler and anti-settling auxiliary agent according to a formula proportion, and dispersing for 10 minutes at the speed of 800 rpm;

3. after the step 2 is finished, pouring the prepared carbon slurry according to the formula proportion, and dispersing for 10 minutes at the speed of 800 rpm;

4. pouring the dispersed material obtained in the step (3) into a sand mill for grinding to obtain a semi-finished product;

5. and (4) adding the residual solvent and the auxiliary agent into the semi-finished product obtained in the step (4), filtering, and mixing with a curing agent to obtain the finished product of the low-temperature curing gravure ink.

The formula comprises the following components in parts by weight:

example two

1. Dispersing a dispersing agent and a solvent (25 wt% of each of the three types) according to a ratio, adding carbon black, then performing dispersing and grinding processes, and storing the ground carbon slurry for later use;

2. mixing resin, solvent (50 wt% of each of the three), extinction filler and anti-settling auxiliary agent according to a formula proportion, and dispersing for 15 minutes at a speed of 600 rpm;

3. after the step 2 is finished, pouring the prepared carbon slurry according to the formula proportion, and dispersing for 15 minutes at the speed of 900 rpm;

The formula comprises the following components in parts by weight:

EXAMPLE III

Coating the low-temperature curing gravure ink on a machine in a gravure manner, wherein the coating manner is the conventional manner; the roller coats the ink on the substrate, and the ink is baked in a hot air box at 90 ℃ and then is dried on the surface without being re-adhered; and (4) rolling after surface drying is finished, placing the rolled material in a 50 ℃ oven for curing for 24h, and then curing to finish the related performance test. The substrate is PET or PI.

FIG. 1 is a conventional PET film material, and FIG. 2 is a conventional PI film material; the substrate is corona treated with a corona prior to coating, which is conventional. The adhesion of the inks of the above examples to both PET and PI was 5B.

FIGS. 3 to 5 are views showing a state where ink is coated on PET, and FIG. 3 is a view showing a masking effect; FIG. 4 is a graph showing the results of 50 alcohol rubs, showing that the ink layer does not bottom out when the abrasion tester rubs back and forth 50 times; fig. 5 is a graph showing the results of 30 rubs against butanone or ethyl ester, and it can be seen that the ink layer is not exposed after 30 rubs against the abrasion tester, and the ink layer is not exposed after 30 rubs against ethyl ester. Likewise, PI is the substrate and the coating also meets the above requirements.

Comparative example

The prior ink is a commercially available ink, the application performance is widely accepted at present, two key performances of both PET (polyethylene terephthalate) ink and PI (polyimide) ink can not reach the performance of the ink, firstly, low-temperature curing is mainly reflected in the surface-drying non-sticky property, and if the surface-drying curing is carried out at the temperature of 80-100 ℃, the surface-drying curing can be sticky after rolling, so the ink can not be used; secondly, the covering performance is that the existing ink has poor covering performance when the film thickness is 3 micrometers, which means that the astigmatism of the mobile phone lighting is obvious, the inventive ink has good covering performance, when the film thickness is 3 micrometers, the mobile phone lighting can only see light spots, and does not see the astigmatism, see the covering performance test results in table 1 and fig. 3. And the surface dyne value of the prior ink is lower than 40.

Table 1 example one ink performance

Comparative example 1

The formula comprises the following components in parts by weight:

the same tests as in examples have revealed that the ink does not satisfy the requirement of 500gf/30 times or more in the methyl ethyl ketone resistance, and the test results are usually 1 to 2 times of wiping, i.e., strike-through.

Comparative example No. two

The formula comprises the following components in parts by weight:

the same tests as in the examples were carried out to find that the ink failed in both alcohol resistance and solvent resistance, and that the alcohol resistance was usually about 500gf/20 times, whereas the methyl ethyl ketone resistance was close to that of the comparative example, and that the ink was strikethrough after 1 to 2 times of wiping.

Example four

1. Dispersing a dispersing agent and a solvent (20 wt% of each) according to a ratio, adding carbon black, then performing dispersing and grinding processes, and storing the ground carbon slurry for later use;

2. mixing resin, solvent (60 wt% of each), extinction filler and anti-settling auxiliary agent according to a formula proportion, and dispersing for 10 minutes at the speed of 800 rpm;

The formula comprises the following components in parts by weight:

the ink was tested in the same manner as in the examples, and it was found that the PI adhesion was less than 5B; the butanone resistance reaches 500gf/27 times of wiping, namely the bottom penetration is realized; when the film thickness is 3 μm, the light spot of the mobile phone is larger.

EXAMPLE five

2. mixing the resin, the solvent (60 wt% of each of the three materials) and the anti-settling auxiliary agent according to the formula proportion, and dispersing at the speed of 800rpm for 10 minutes;

The formula comprises the following components in parts by weight:

in this example, no matting filler was added, the surface dyne value of the ink coating was reduced to 43, and when no matting filler was added, the ink shrank during application, resulting in poor appearance of the coating.

The existing polyurethane system gravure black ink, epoxy system gravure black ink and polyester system gravure black ink have several disadvantages: under normal temperature, alcohol, ester and ketone solvents can swell and degrade, so that the prepared film coating has relatively poor chemical resistance; because the long-chain structure is formed by the reaction of the polyol with the terminal hydroxyl and the isocyanate, the molecular weight of the product is usually larger, and the viscosity of the ink is higher and the solid content is lower when the product is used for preparing an ink formula; the weather resistance is poor, the adhesion with untreated PET/PI base materials is poor, amine curing agents are generally required to be used as hardeners for carrying out final curing of the ink layer, but generally, the reactions all need higher reaction temperature, and for thinner and thinner film materials, the higher temperature is more and more unsuitable; the surface dyne value after curing is usually low, and is difficult to reach above 40, in this case when the black ink is required to provide excellent color difference, it is difficult to cover the black ink by covering it with a matte oil; the coating performance of the carbon black particles is general, the covering power after film forming is poor, the coating can only be applied to products with low covering requirements, the alcohol resistance is poor, the ethyl ester and butanone resistance is poor, the coating can not be directly used as surface coating ink, and a layer of matte oil needs to be added on the surface of the coating to improve the chemical resistance; the scratch resistance of the ink surface is poor.

The purpose of the invention and the technical problem to be solved are as follows:

according to the invention, the special modified polyester resin with a smaller molecular weight (as a main resin) is matched with the polyurethane resin which can be perfectly fused with the special modified polyester resin, so that the wettability of the resin to carbon black is increased, the color development of the ink is improved, meanwhile, due to the factors of a solvent and a dispersant, the adhesive force of the ink after curing and film forming to PET and PI base materials is excellent, the matched polyurethane resin is used as the main resin for grinding the carbon black, the effect of grinding the carbon black is very good by matching with Lu Fu 20000 dispersant, and meanwhile, the existence of the polyurethane resin has a certain promotion effect on the promotion of the adhesive force; the ink layer formed after the reaction of the resin and the isocyanate curing agent is compact and firm, has excellent alcohol resistance, and also has certain effects of resisting the wiping of ethyl ester and butanone; the ink system has higher reaction speed and good solvent release performance, so that the effect of quick surface drying and no back adhesion can be realized at lower temperature (80-100 ℃).

Claims

1. The low-temperature curing gravure ink suitable for PET and PI substrates is characterized by comprising hyperbranched modified polyester resin, epoxy modified polyurethane resin, a solvent, a dispersing agent, carbon black, a delustering filler, an anti-settling additive, an auxiliary agent and a curing agent.

2. Low temperature curing intaglio ink suitable for PET and PI substrates according to claim 1 characterized in that,

the composition is characterized by comprising the following raw materials in parts by weight:

3. the low temperature curing intaglio ink suitable for PET and PI substrates according to claim 1 characterized in that the hyperbranched polyester resin has a weight average molecular weight not exceeding 6000; a hydroxyl number of 50 to 100; the glass transition temperature of the resin is above 50 ℃.

4. The low-temperature curing gravure ink suitable for PET and PI substrates as claimed in claim 1, wherein the dispersant is one or more of BYK-163, Luoborun 20000, Luoborun 27000; the carbon black is one or more of Columbia 1200, Mitsubishi MA11, Kabot S90B, and ZG600T of Zhihua new material; the matting filler comprises fumed silica powder; the solvent is one or more of ethyl acetate, butanone, acetone and methyl isobutyl ketone; the anti-settling additive is one or more of white carbon black, polyethylene wax slurry and BYK-410 anti-settling additive.

5. Low temperature curing intaglio ink suitable for PET and PI substrates according to claim 4 characterized by the fact that the solvents are ethyl acetate, butanone and methyl isobutyl ketone.

6. Low temperature curing intaglio ink suitable for PET and PI substrates according to claim 1 characterized in that the auxiliary agent is an adhesion promoter and/or a drier.

7. Use of the low temperature curing intaglio inks suitable for PET and PI substrates according to claim 1 for the preparation of PET and/or PI based coatings.

8. The method for preparing the low-temperature curing intaglio ink suitable for the PET and PI substrates as recited in claim 1, wherein a dispersant is dispersedly mixed with a solvent and carbon black to obtain carbon slurry; dispersing and mixing resin, a solvent, a delustering filler and an anti-settling auxiliary agent, then dispersing and mixing with the carbon slurry, adding the solvent and the auxiliary agent, and then filtering; and mixing with a curing agent to obtain the finished product of the low-temperature curing gravure ink.

9. A black composite comprising a substrate and the low temperature curing gravure ink of claim 1 suitable for PET and PI substrates.

10. The black composite of claim 9, wherein the substrate is PET and/or PI.