UV insulating ink for ultrathin touch screen and preparation method of UV insulating ink

Abstract

According to the UV insulating ink for the ultrathin touch screen and the preparation method of the UV insulating ink, the UV insulating ink for the ultrathin touch screen comprises epoxy resin, a photoinitiator, a solvent, an auxiliary and filler, the epoxy resin comprises at least one of aliphatic epoxy resin, flexible epoxy resin and phenolic aldehyde modified epoxy resin, the photoinitiator comprises a cationic photoinitiator, and aims to improve the permeability, flexibility and reliability of the insulating ink, so that the insulating ink is suitable for an ultrathin touch screen.

Description

Technical Field

[0001] The invention relates to the technical field of ink preparation, in particular to UV insulating ink for ultra-thin touch screens and a preparation method thereof. Background Art

[0002] With the rapid development of computer technology, input accessories such as keyboards and mice of electronic devices such as mobile phones and computers are gradually integrated into touch screen technology so that people can have a better user experience. At present, most of the touch screens on the market are capacitive touch screens. Among them, thin-film capacitive touch screens are lighter, less expensive, and more flexible than ordinary glass touch screens. ITO glass is used as a conductive material in conventional thin-film touch screens, but because ITO glass is thicker, electronic devices such as mobile phones are larger and heavier, and are not easy to carry. In order to give people a better experience, ITO glass is gradually improved into an ultra-thin conductive material with a metal grid. In ultra-thin conductive materials, because the metal grid is easily affected by heat and moisture, which causes aging and affects performance, a layer of OC insulating ink needs to be spread on it. This ink not only needs to have high permeability, but also needs to have certain flexibility and reliability requirements. Summary of the invention

[0003] In view of this, the object of the present invention is to provide a UV insulating ink for an ultra-thin touch screen, aiming to improve the permeability, flexibility and reliability of the insulating ink so as to make it suitable for the ultra-thin touch screen.

[0004] The invention provides a UV insulating ink for an ultra-thin touch screen, the components of which include: epoxy resin, a photoinitiator, a solvent, an auxiliary agent and a filler, the epoxy resin includes at least one of aliphatic epoxy resin, flexible epoxy resin and phenolic modified epoxy resin, and the photoinitiator includes a cationic photoinitiator.

[0005] Specifically, epoxy resin has excellent electrical insulation, adhesion, chemical resistance and low shrinkage, so it is more appropriate to use epoxy resin as the main resin in the insulating ink used on ultra-thin touch screens. Due to the high rigidity of epoxy resin structure, the product is easy to be brittle and hard. In order to solve the flexibility problem, it is necessary to introduce an appropriate amount of flexible epoxy resin into the epoxy resin. The flexible epoxy resin contains a flexible segment. The epoxy resin molecule has a large rotation angle and a molecular structure with many isomers, which can provide better flexibility. In addition, phenolic modified epoxy resin can provide high heat resistance and chemical resistance for UV insulating ink for ultra-thin touch screens, because the phenolic resin structure is a body structure, with high cross-linking density, large energy-reinforcing force and excellent heat resistance stability. Finally, the adhesion effect can be improved by adjusting the viscosity to enhance the wetting ability. On the one hand, it can be enhanced by adding a low-viscosity aliphatic epoxy resin, and on the other hand, the viscosity can be adjusted by adding a suitable solvent to enhance the wetting effect.

[0006] In the prior art, UV curing of insulating ink is still a minority, and UV curing is mostly divided into free radical curing, cationic curing, etc. Although the free radical curing commonly used in the prior art has the characteristics of high efficiency, it also has the disadvantage of large shrinkage, and thin film materials often need to avoid problems such as large shrinkage, because large shrinkage will cause the metal grid to shrink and thus affect the performance of the film. The present invention uses a cationic photoinitiator to cure the UV insulating ink for ultra-thin touch screens in a cationic curing manner, which can avoid the problem of large shrinkage and improve the degree of curing.

[0007] In one embodiment, the component further includes a sensitizer, and the sensitizer is at least one of UVS-1331, UVS-2171, DETX and 9,10-diethoxy-2-ethylanthracene.

[0008] Specifically, the types of sensitizers and photoinitiators can produce unexpected effects under specific combinations. For example, according to the ratio of the prior art, the above-mentioned sensitizer has a better photoinitiating effect when combined with sulfonium salts than with iodonium salts. However, if a specific sensitizer and a specific iodonium salt are adjusted to an appropriate ratio, they can also promote photocuring efficiency and curing depth to a certain extent.

[0009] In one embodiment, the cationic photoinitiator includes UVI-6976 (triaryl sulfonium hexafluoroantimonate), UVI-6992 (triaryl sulfonium hexafluorophosphate), and omnicat250 (diaryl iodonium hexafluorophosphate).

[0010] In one embodiment, the photoinitiator is UVI-6992 and / or UVI-6976; the sensitizer is one or more of UVS-1331, UVS-2171 and 9,10-diethoxy-2-ethylanthracene.

[0011] In one embodiment, the photoinitiator is UVI-6976, the sensitizer is UVS-2171, and the ratio of the photoinitiator content to the sensitizer content is less than or equal to 3:1; or the photoinitiator is UVI-6976, the sensitizer is UVS-1331, and the ratio of the photoinitiator content to the sensitizer content is less than or equal to 6:1; or the photoinitiator is UVI-6992, the sensitizer is UVS-1331 and / or UVS-2171, and the photoinitiator content is 0.8%-1.2% of the sensitizer content, preferably 1%.

[0012] In one embodiment, the photoinitiator is omnicat250, and the sensitizer is at least one of DETX, UVS-1331 and UVS-2171.

[0013] In one embodiment, the sensitizer is UVS-2171, and the ratio of the photoinitiator content to the sensitizer content is less than 6:1; or the sensitizer is UVS-1331, and the ratio of the photoinitiator content to the sensitizer content is less than 10:1.

[0014] In one embodiment, the aliphatic epoxy resin includes at least one of bisphenol A epoxy resin, bisphenol F epoxy resin, and alicyclic epoxy resin.

[0015] In one embodiment, the flexible epoxy resin includes at least one of a polyether modified epoxy resin, a polyurethane modified epoxy resin, a dimer acid modified epoxy resin, a nitrile rubber modified epoxy resin and a long straight chain aliphatic epoxy resin.

[0016] In one embodiment, the components are calculated in parts by weight as follows: 40-85 parts of the epoxy resin, 2-8 parts of the photoinitiator, 1-10 parts of the solvent, 1-10 parts of the auxiliary agent, and 10-30 parts of the filler.

[0017] In one embodiment, the solvent is a mixture of one or more of n-butanol, cyclohexanone, butanone, dimethylacetamide, toluene, ethylene glycol methyl ether acetate and ethyl acetate, the auxiliary agent is one or more of a leveling agent, a defoaming agent and a coupling agent, wherein the weight fraction of the leveling agent is 0.5-2 parts, the weight fraction of the defoaming agent is 0.5-2 parts, the weight fraction of the coupling agent is 1-5 parts, and the filler is fumed silica.

[0018] The present invention also provides a method for preparing the UV insulating ink for ultra-thin touch screen as described above, comprising the following steps: dispersing the components uniformly and rolling them on a three-roller machine until the fineness is less than 10 μm. Implementation

[0019] The specific embodiments of the present invention are described in detail below. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the description of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] The terms "comprises," "comprising," or any other variations thereof, are intended to cover a non-exclusive inclusion of the elements listed and may also include additional elements not expressly listed.

[0021] It is worth mentioning that the present invention only lists a number of representative specific implementations, which is intended to reflect the beneficial effects of the present invention, and is not equivalent to the implementations shown below being all implementations of the present invention. Example 1

[0022] The present invention provides a UV ink, the components of which include: 60 parts of epoxy resin, 5 parts of photoinitiator, 5 parts of solvent, 5 parts of auxiliary agent, 20 parts of filler, the epoxy resin is a mixture of bisphenol A epoxy resin, polyether modified epoxy resin and phenolic modified epoxy resin; the photoinitiator is UVI-6976; the sensitizer is UVS-2171, and the addition ratio of UVI-6976 to UVS-2171 is 2:1; the solvent is n-butanol; the auxiliary agent is 1 part of leveling agent, 1 part of defoamer and 2 parts of coupling agent; the filler is fumed silica. Performance tests show that the ink has good insulation, excellent flexibility, low resistance change rate and short curing time. Example 2

[0023] This embodiment provides a UV ink, which is different from Embodiment 1 in that the epoxy resin is a mixture of bisphenol F epoxy resin, polyurethane modified epoxy resin and phenolic modified epoxy resin; the solvent is cyclohexanone; the photoinitiator is UVI-6976, the sensitizer is UVS-1331, and the addition ratio of UVI-6976 and UVS-1331 is 5:1. Example 3

[0024] This embodiment provides a UV ink, which is different from Embodiment 1 in that the epoxy resin is a mixture of alicyclic epoxy resin, dimer acid-modified epoxy resin and phenolic modified epoxy resin; the solvent is butanone; the photoinitiator is UVI-6992, the sensitizer is UVS-1331, and the content of UVI-6992 is 1% of the content of UVS-1331. Example 4

[0025] This embodiment provides a UV ink, which is different from Embodiment 1 in that the epoxy resin is a mixture of alicyclic epoxy resin, long straight-chain aliphatic epoxy resin and phenolic modified epoxy resin; the solvent is dimethylacetamide; the photoinitiator is UVI-6992, the sensitizer is UVS-2171, and the content of UVI-6992 is 1% of the content of UVS-2171. Example 5

[0026] This embodiment provides a UV ink, which is different from Embodiment 1 in that the epoxy resin is a mixture of alicyclic epoxy resin, nitrile rubber modified epoxy resin and phenolic modified epoxy resin; the solvent is toluene; the photoinitiator is omnicat250, the sensitizer is UVS-2171, and the ratio of omnicat250 content to UVS-2171 content is 5:1. Example 6

[0027] This embodiment provides a UV ink, which is different from Embodiment 1 in that the solvent is ethylene glycol methyl ether acetate; the photoinitiator is omnicat250, the sensitizer is UVS-1331, and the ratio of the photoinitiator content to the sensitizer content is 9:1. Example 7

[0028] This embodiment provides a UV ink, which is different from the embodiment 1 in that it does not contain a sensitizer.

[0029] Comparative Example This embodiment provides a UV ink, which is different from the embodiment 1 in that the photoinitiator is a combination of 184 and TPO. The free radical curing initiator leads to large curing shrinkage.

[0030] Test Results The UV inks of Examples 1 to 7 and Comparative Examples 1 to 2 were tested for performance, and the test results are shown in Table 1: Table 1 project Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Comparative Example Insulation >1000Ω >1000Ω >1000Ω >1000Ω >1000Ω >1000Ω >1000Ω >1000Ω Flexibility >20W times >20W times >20W times >20W times >20W times >20W times >20W times >20W times Resistance change rate ≦2.5% 3.5~4% 3~4% 3~4.5 % 3~4% 3.5~5% 6%~7% 6%~8% Curing time 20s 25s 25s 26s 30s 28s 40s 45s The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the attached claims.

Claims

1. A UV insulating ink for ultra-thin touch screens, It is characterized in that The components include: epoxy resin, photoinitiator, solvent, auxiliary agent and filler. The epoxy resin includes at least one of aliphatic epoxy resin, flexible epoxy resin and phenolic modified epoxy resin. The photoinitiator includes cationic photoinitiator.

2. The UV insulating ink for ultra-thin touch screen according to claim 1, It is characterized in that The components further include a sensitizer, which is at least one of UVS-1331, UVS-2171, DETX and 9,10-diethoxy-2-ethylanthracene.

3. The UV insulating ink for ultra-thin touch screen according to claim 2, It is characterized in that The cationic photoinitiator includes triaryl sulfonium hexafluoroantimonate, triaryl sulfonium hexafluorophosphate, and diaryl iodonium hexafluorophosphate.

4. The UV insulating ink for ultra-thin touch screen according to claim 3, It is characterized in that The photoinitiator is triaryl sulfonium hexafluorophosphate and / or triaryl sulfonium hexafluoroantimonate; the sensitizer is one or more of UVS-1331, UVS-2171 and 9,10-diethoxy-2-ethylanthracene.

5. The UV insulating ink for ultra-thin touch screen according to claim 4, It is characterized in that The photoinitiator is a triaryl sulfonium hexafluoroantimonate, the sensitizer is UVS-2171, and the ratio of the photoinitiator content to the sensitizer content is less than or equal to 3:1; or the photoinitiator is a triaryl sulfonium hexafluoroantimonate, the sensitizer is UVS-1331, and the ratio of the photoinitiator content to the sensitizer content is less than or equal to 6:1; or the photoinitiator is a triaryl sulfonium hexafluorophosphate, the sensitizer is UVS-1331 and / or UVS-2171, and the photoinitiator content is 0.8%-1.2% of the sensitizer content.

6. The UV insulating ink for ultra-thin touch screen according to claim 3, It is characterized in that The photoinitiator is diaryl iodonium hexafluorophosphate, and the sensitizer is at least one of DETX, UVS-1331 and UVS-2171.

7. The UV insulating ink for ultra-thin touch screen according to claim 6, It is characterized in that The sensitizer is UVS-2171, and the ratio of the photoinitiator content to the sensitizer content is less than 6:1; or the sensitizer is UVS-1331, and the ratio of the photoinitiator content to the sensitizer content is less than 10:

1.

8. The UV insulating ink for ultra-thin touch screen according to claim 1, It is characterized in that The aliphatic epoxy resin includes at least one of bisphenol A epoxy resin, bisphenol F epoxy resin and alicyclic epoxy resin.

9. The UV insulating ink for ultra-thin touch screen according to claim 1, It is characterized in that The flexible epoxy resin includes at least one of polyether modified epoxy resin, polyurethane modified epoxy resin, dimer acid modified epoxy resin, nitrile rubber modified epoxy resin and long straight chain aliphatic epoxy resin.

10. The method for preparing the UV insulating ink for ultra-thin touch screen according to any one of claims 1 to 9, It is characterized in that The method comprises the following steps: the components are evenly dispersed and then rolled on a three-roller machine until the fineness is less than 10 μm.