A UV-curable EVA film suitable for electronic packaging

Abstract

The invention discloses a UV-curable EVA adhesive film suitable for electronic packaging, which is characterized by comprising the following raw materials in parts by weight: 85-95 parts of EVA, 6-15 parts of light diffuser, 2-10 parts of antacid and 2-10 parts of auxiliary agent; the auxiliary agent comprises the following raw materials in parts by weight: 0.01-0.05 parts of pre-crosslinking agent, 0.5-1 parts of crosslinking auxiliary agent, 0.5-5 parts of photoinitiator, 0.5-5 parts of silane coupling agent, 0.5-5 parts of crosslinking curing agent and 0.01-0.05 parts of antioxidant; the UV-curable EVA adhesive film suitable for electronic packaging of the invention provides a use method in the field of electronic optical packaging; the UV-curable EVA adhesive film suitable for electronic packaging has good haze, is not easy to age and is not easy to peel off after being used in electronic optical packaging.

Description

Technical Field

[0001] The invention relates to the technical field of electronic packaging, in particular to a UV-curing EVA adhesive film suitable for electronic packaging. Background Art

[0002] In the past decade, due to technological progress, my country has achieved domestic production of ethylene vinyl acetate, and the production capacity of EVA has been further expanded, making EVA resin cheaper. At present, EVA resin has been widely used in shoe materials and photovoltaic packaging due to its low price and easy processing.

[0003] However, the direct application of EVA resin in the field of electronic optical packaging will cause defects such as easy aging and easy peeling. Currently, EVA cannot be used in the field of electronic optical packaging. It is encapsulated with acrylate adhesives or polyurethane-modified acrylate adhesives. Summary of the invention

[0004] The purpose of the present invention is to overcome the above-mentioned defects in the prior art and provide a UV-curable EVA film suitable for electronic packaging. After the EVA film is modified, it can be suitable for electronic packaging and is not easy to age or peel off.

[0005] To achieve the above object, the present invention provides a UV-curable EVA film suitable for electronic packaging, comprising the following raw materials in parts by weight:

[0006] EVA: 85-95 parts, light diffuser: 6-15 parts, antacid 2-10 parts and auxiliary agent 2-10 parts;

[0007] The auxiliary agent comprises the following raw materials in parts by weight:

[0008] Pre-crosslinking agent: 0.01-0.05 parts, crosslinking aid: 0.5-1 parts, photoinitiator: 0.5-5 parts, silane coupling agent: 0.5-5 parts, crosslinking curing agent: 0.5-5 parts, antioxidant: 0.01-0.05 parts.

[0009] Preferably, the EVA is a copolymer of ethylene vinyl acetate having a vinyl acetate VA content of 25%-35% and an MI value of 25-35 g / 10min.

[0010] Preferably, the light diffuser includes: polymethyl methacrylate microspheres, polyethylene microspheres, one or a mixture of talcum powder, calcium carbonate, diatomaceous earth, and silicon dioxide.

[0011] Preferably, the particle size of the light diffusing agent is between 100 nm and 3 μm.

[0012] Preferably, the surface of the light diffuser is coated with organic matter and processed into EVA masterbatch with a concentration of 25%-40% before use.

[0013] Preferably, the antacid comprises: one or a mixture of sodium carbonate, sodium sulfate, sodium bicarbonate, sodium bisulfate, calcium oxide, and barium oxide.

[0014] Preferably, the surface of the antacid is coated with organic matter and processed into EVA masterbatch with a concentration of 1%-2% before use.

[0015] Preferably, the pre-crosslinking agent in the auxiliary agent includes one or a mixture of organic peroxides or azo compounds;

[0016] The organic peroxide includes: one or a mixture of cumene peroxide, di-tert-butyl peroxide, diisopropylbenzene hydroperoxide, 2,5-dimethyl-2,5-di-tert-butyl peroxide hexane, 4,4-di(tert-amyl peroxy) valeric acid n-butyl ester, tert-butyl peroxy 2-ethylhexyl carbonate, 3,3-di(tert-butyl peroxy) ethyl butyrate;

[0017] The cross-linking auxiliary agent in the auxiliary agent includes: one or a mixture of triallyl isocyanurate, triallyl cyanurate, trimethylolpropane trimethacrylate, and diethylene glycol dimethacrylate;

[0018] The photoinitiator in the auxiliary agent includes: 2-hydroxy-2-methyl-1-phenyl-1-propanone, 1-hydroxycyclohexyl phenyl ketone, 2,4,6-trimethylbenzoyl diphenyl phosphine oxide, 2,4,6-trimethylbenzoyl phenyl phosphonic acid ethyl ester, 2-dimethylamino-2-benzyl-1-[4-(4-morpholinyl)phenyl]-1-butanone, 2-methyl-2-(4-morpholinyl)-1-[4-(methylthio)phenyl]-1-propanone, 2-hydroxy-2-methyl-1-(4-hydroxyethoxy) or a mixture of the above;

[0019] The silane coupling agent in the auxiliary agent includes: one or a mixture of vinyl triethoxysilane, vinyl trimethoxysilane, vinyl triperoxy tert-butyl silane, vinyl triacetoxy silane, and vinyl tri(β-methoxyethoxy) silane;

[0020] The cross-linking curing agent in the auxiliary agent includes: one or a mixture of isobornyl ester, N-acryloylmorpholine, pentaerythritol triacrylate;

[0021] The antioxidant in the auxiliary agent includes a primary antioxidant and a secondary antioxidant, wherein the primary antioxidant is octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate octadecyl alcohol ester; the secondary antioxidant is tris(4-nonylphenol) phosphite or tris(2,4-di-tert-butylphenyl) phosphite, or a mixture of the two.

[0022] Preferably, the UV-curable EVA film suitable for electronic packaging has a thickness of 150-180 μm.

[0023] Preferably, it also includes polyethylene terephthalate and polyethylene protective films or polyethylene terephthalate and polyethylene terephthalate protective films or polyethylene and polyethylene protective films attached to the upper and lower surfaces of a UV-cured EVA film suitable for electronic packaging.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1. The UV-curable EVA film suitable for electronic packaging of the present invention provides a use method in the field of electronic optical packaging.

[0026] 2. This UV-curable EVA film suitable for electronic packaging is suitable for electronic optical packaging and has excellent properties such as good haze, not easy to age and not easy to peel off. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0028] Figure 1 It is a schematic structural diagram of a UV-curable EVA film suitable for electronic packaging provided in the first embodiment of the present invention;

[0029] Figure 2 This is a physical picture of the modified UV-cured EVA film of Example 1 of the present invention in the peel strength test experiment of the PET test plate provided by Example 3 of the present invention;

[0030] Figure 3 This is a physical picture of the common EVA adhesive film of Example 4 provided in Example 3 of the present invention in a peel strength test experiment on a PET test plate;

[0031] Figure 4This is a physical picture of the modified UV-cured EVA film of Example 1 provided in Example 3 of the present invention in a PCT aging test experiment;

[0032] Figure 5 This is a physical picture of the common EVA film of Example 4 provided in Example 3 of the present invention in the PCT aging test experiment;

[0033] Figure 6 This is a physical picture of the modified UV-cured EVA film of Example 1 of the present invention observed through a 25x microscope in a double 85 aging test experiment;

[0034] Figure 7 This is a real picture of the common EVA film of Example 4 provided in Example 3 of the present invention observed through a 25x microscope in a double 85 aging test experiment.

[0035] Included in the figure are:

[0036] 1. Upper polyethylene protective film; 2. UV-cured EVA film; 3. Lower polyethylene terephthalate. DETAILED DESCRIPTION

[0037] The technical scheme in this embodiment of the present invention will be clearly and completely described below in conjunction with the drawings in this embodiment of the present invention. Obviously, the described embodiment is one embodiment of the present invention, not all embodiments of the present invention. Based on this embodiment of the present invention, all other embodiments of the present invention obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] Embodiment 1:

[0039] Figure 1 This is a schematic structural diagram of a UV-curable EVA film suitable for electronic packaging according to Embodiment 1 of the present invention.

[0040] The UV-curable EVA film suitable for electronic packaging has a film thickness of 150-180 μm.

[0041] The upper and lower surfaces of the UV-cured EVA adhesive film suitable for electronic packaging are adhered with polyethylene terephthalate and polyethylene protective films or polyethylene terephthalate and polyethylene terephthalate protective films or polyethylene and polyethylene protective films.

[0042] Among them, Figure 1 As shown, in this embodiment 1, an upper polyethylene protective film 1 (PE) is attached to a UV-curing EVA adhesive film 2, and a lower polyethylene terephthalate 3 (PET) is attached to a lower portion of the UV-curing EVA adhesive film 2.

[0043] A UV-curable EVA film 2 suitable for electronic packaging according to the first embodiment of the present invention comprises the following raw materials in parts by weight:

[0044] Main ingredient: EVA: 85-95 parts, EVA is a copolymer of ethylene vinyl acetate with a vinyl acetate VA content of 25-35% and an MI value of 25-35g / 10min.

[0045] Light diffuser: 6-15 parts, the particle size of the light diffuser is 100nm-3μm. The light diffuser includes: polymethyl methacrylate microspheres, polyethylene microspheres, talcum powder, calcium carbonate, diatomaceous earth, silicon dioxide, or a mixture of several of them. The surface of the light diffuser is coated with organic matter and processed into 25%-40% EVA masterbatch for use.

[0046] Antacid: 2-10 parts, the antacid includes: sodium carbonate, sodium sulfate, sodium bicarbonate, sodium bisulfate, calcium oxide, barium oxide, one or a mixture of several. The surface of the antacid is coated with organic matter and processed into 1%-2% concentration EVA masterbatch for use.

[0047] Auxiliary agent: 2-10 parts, which includes the following raw materials in parts by weight:

[0048] Pre-crosslinking agent: 0.01-0.05 parts, the pre-crosslinking agent includes: one or a mixture of organic peroxides or azo compounds, wherein:

[0049] Organic peroxides include: one or a mixture of cumene peroxide, di-tert-butyl peroxide, diisopropylbenzene hydroperoxide, 2,5-dimethyl-2,5-di-tert-butyl peroxyhexane, 4,4-di(tert-amylperoxy) valeric acid n-butyl ester, tert-butyl peroxy 2-ethylhexyl carbonate, 3,3-di(tert-butylperoxy) ethyl butyrate;

[0050] Cross-linking aid: 0.5-1 part, the cross-linking aid includes: one or a mixture of triallyl isocyanurate, triallyl cyanurate, trimethylolpropane trimethacrylate, diethylene glycol dimethacrylate;

[0051] Photoinitiator: 0.5-5 parts, the photoinitiator includes: 2-hydroxy-2-methyl-1-phenyl-1-propanone, 1-hydroxycyclohexyl phenyl ketone, 2,4,6-trimethylbenzoyl diphenyl phosphine oxide, 2,4,6-trimethylbenzoyl phenyl phosphonic acid ethyl ester, 2-dimethylamino-2-benzyl-1-[4-(4-morpholinyl)phenyl]-1-butanone, 2-methyl-2-(4-morpholinyl)-1-[4-(methylthio)phenyl]-1-propanone, 2-hydroxy-2-methyl-1-(4-hydroxyethoxy) one or more mixtures;

[0052] Silane coupling agent: 0.5-5 parts, the silane coupling agent includes: one or a mixture of vinyl triethoxysilane, vinyl trimethoxysilane, vinyl triperoxy tert-butyl silane, vinyl triacetoxy silane, vinyl tri(β-methoxyethoxy) silane;

[0053] Cross-linking curing agent: 0.5-5 parts, the cross-linking curing agent includes: isobornyl ester, N-acryloylmorpholine, pentaerythritol triacrylate, one or a mixture of several thereof;

[0054] Antioxidant: 0.01-0.05 parts, the antioxidant includes a primary antioxidant and a secondary antioxidant, wherein the primary antioxidant is octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate octadecyl alcohol ester; the secondary antioxidant is tris(4-nonylphenol) phosphite or tris(2,4-di-tert-butylphenyl) phosphite, or a mixture of the two.

[0055] Embodiment 2:

[0056] Embodiment 2 of the present invention provides a method for preparing a UV-curable EVA film suitable for electronic packaging, and its production process is as follows:

[0057] Step S1: mixing EVA, a light diffuser, an antacid, an auxiliary agent and an organic solvent according to the raw material proportions in parts by weight of a UV-curable EVA film suitable for electronic packaging according to the first embodiment above;

[0058] Step S2: adding the mixed material in step S1 into the hopper of a single screw extruder, performing melt mixing through the single screw extruder, and extruding through the die head of the single screw extruder, wherein each temperature section of the die head is 75° C.-90° C.;

[0059] Step S3: After extrusion by the single screw extruder, the lower PET protective film and the UV-cured EVA film are pressed together by a hot press, and the surface of the lower PET protective film is textured by an embossing machine;

[0060] Step S4: pressing and cooling the combined lower PET protective film and UV-cured EVA film by a casting roll;

[0061] Step S5: Press the upper PE film, the lower PET protective film and the UV-cured EVA film together through a hot press;

[0062] Step S6: trimming the upper PE film, the UV-cured EVA film and the lower PET protective film by a trimming machine;

[0063] Step S7: Reeling the material through a reel;

[0064] Step S8: taking out from the winder and packaging.

[0065] Embodiment three:

[0066] Example 3 of the present invention provides experimental data on haze test, aging resistance test and peel strength test of the modified UV-cured EVA film of the present invention and the ordinary EVA film without adding light diffusing agent and antacid.

[0067] This experimental data uses six examples, among which the formula table of example 1 to example 6 is as follows Table 1:

[0068]

[0069]

[0070] According to Table 1, Example 1, Example 2 and Example 3 are respectively a UV-cured EVA film suitable for electronic packaging of the present invention, and Example 4, Example 5 and Example 6 are respectively ordinary EVA films without adding light diffusing agent and antacid.

[0071] Examples 1 to 6 in Table 1 were mixed according to the formulation ingredients described in Table 1, and were prepared according to the preparation method of Example 2 above.

[0072] Then, the sample films of Examples 1 to 6 were subjected to tests such as haze test, aging resistance test and peel strength test, and the experimental data are shown in Table 2 below:

[0073]

[0074] According to Table 2, the following experimental analysis conclusions can be obtained:

[0075] 1. The first row of Table 2 lists Examples 1 to 6 respectively, wherein Examples 1 to 3 are respectively the modified UV-cured EVA films 2 of the present invention, and Examples 4 to 6 are respectively ordinary EVA films.

[0076] 2. The second row of Table 2: The molding thickness of Examples 1 to 6 is the same.

[0077] 3. The third row of Table 2: The transmittance of the modified UV-cured EVA film 2 of the present invention is similar to that of the ordinary EVA film.

[0078] 4. The fourth row of Table 2: The modified UV-cured EVA film of the present invention has high haze and good haze performance (if used in a display, it can effectively avoid the glare of the display), while the ordinary EVA film has low haze and poor haze performance.

[0079] 5. The fifth row of Table 2: Figure 2 As shown, the modified UV-cured EVA film of the present invention has a larger peeling force required for the PET test plate, and its peeling strength is high. Figure 2 In the embodiment, the modified UV-cured EVA film of the present invention is obviously white, indicating that the bonding strength is high. Figure 3 As shown, the peeling force required for the ordinary EVA film on the PET test plate is small, and its peeling strength is low.

[0080] 6. The sixth row of Table 2: Figure 4 and Figure 5 As shown, after testing for 32 hours under a PCT aging test environment at a temperature of 110 degrees and a relative humidity of 100 degrees, the modified UV-cured EVA film 2 of the present invention has a normal appearance, while the ordinary EVA film has obvious snowflake-like traces, indicating that the barrier to water vapor is not good.

[0081] 7. The seventh row of Table 2: Figure 6 and seven As shown, after testing for 200 hours under the double 85 aging test environment, the modified UV-cured EVA film 2 of the present invention is normal, there is no water vapor in the flow channel, and the ordinary EVA film turns yellow, and water vapor enters and bubbles exist.

[0082] 8. The eighth row of Table 2: After being tested for 200 hours under a high-low temperature aging environment of 80 degrees at high temperature and -30 degrees at low temperature, the modified UV-cured EVA film 2 of the present invention and the ordinary EVA film are normal and have no shrinkage.

[0083] Therefore, from the 2nd, 3rd, 4th, 5th, 6th, 7th and 8th points of the above experimental analysis conclusions, it can be obtained that, compared with ordinary EVA films of the same thickness, the modified UV-cured EVA film 2 of the present invention, thanks to the addition of a certain proportion of light diffuser and antacid (in Example 1, Example 2 and Example 3, the sum of the light diffuser and the antacid is 4% of the total formula), can maintain better light transmittance, better haze, less prone to aging and less prone to peeling, and therefore, can replace acrylate adhesives or polyurethane-modified acrylate adhesives for packaging, providing a use method in the field of electronic optical packaging.

[0084] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A UV-curable EVA film suitable for electronic packaging, characterized in that: The invention comprises the following raw materials in parts by weight: EVA: 94 parts, light diffuser: 3 parts, antacid 1 part and auxiliary agent 2 parts, the sum of light diffuser and antacid is 4% of the total formula; The auxiliary agent comprises the following raw materials in parts by weight: Pre-crosslinking agent: 0.03 parts, crosslinking aid: 1-2 parts, photoinitiator: 2-5 parts, silane coupling agent: 0.5-1 parts, crosslinking curing agent: 3-5 parts, antioxidant: 0.2-0.4 parts; The EVA is a copolymer of ethylene vinyl acetate with a vinyl acetate VA content of 25%-35% and an MI value of 25-35 g / 10min; The light diffuser includes: polymethyl methacrylate microspheres, polyethylene microspheres, one or a mixture of talcum powder, calcium carbonate, diatomaceous earth, and silicon dioxide; The particle size of the light diffusing agent is 100nm-3μm; The surface of the light diffuser is treated with organic coating and processed into EVA masterbatch with a concentration of 25%-40% before use; The antacid includes: one or a mixture of sodium carbonate, sodium sulfate, sodium bicarbonate, sodium bisulfate, calcium oxide, and barium oxide; The surface of the antacid is coated with organic matter and processed into EVA masterbatch with a concentration of 1%-2% before use; The pre-crosslinking agent in the auxiliary agent includes one or a mixture of two of an organic peroxide or an azo compound; The organic peroxide includes: one or a mixture of cumene peroxide, di-tert-butyl peroxide, diisopropylbenzene hydroperoxide, 2,5-dimethyl-2,5-di-tert-butyl peroxide hexane, 4,4-di(tert-amyl peroxy) valeric acid n-butyl ester, tert-butyl peroxy 2-ethylhexyl carbonate, 3,3-di(tert-butyl peroxy) ethyl butyrate; The cross-linking auxiliary agent in the auxiliary agent includes: one or a mixture of triallyl isocyanurate, triallyl cyanurate, trimethylolpropane trimethacrylate, and diethylene glycol dimethacrylate; The photoinitiator in the auxiliary agent includes: 2-hydroxy-2-methyl-1-phenyl-1-propanone, 1-hydroxycyclohexyl phenyl ketone, 2,4,6-trimethylbenzoyl diphenyl phosphine oxide, 2,4,6-trimethylbenzoyl phenyl phosphonic acid ethyl ester, 2-dimethylamino-2-benzyl-1-[4-(4-morpholinyl)phenyl]-1-butanone, 2-methyl-2-(4-morpholinyl)-1-[4-(methylthio)phenyl]-1-propanone, 2-hydroxy-2-methyl-1-(4-hydroxyethoxy) or a mixture of the above; The silane coupling agent in the auxiliary agent includes: one or a mixture of vinyl triethoxysilane, vinyl trimethoxysilane, vinyl triperoxy tert-butyl silane, vinyl triacetoxy silane, and vinyl tri(β-methoxyethoxy) silane; The cross-linking curing agent in the auxiliary agent includes: one or a mixture of isobornyl ester, N-acryloylmorpholine, pentaerythritol triacrylate; The antioxidant in the auxiliary agent includes a primary antioxidant and a secondary antioxidant, wherein the primary antioxidant is octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate octadecyl alcohol ester; the secondary antioxidant is tris(4-nonylphenol) phosphite or tris(2,4-di-tert-butylphenyl) phosphite, or a mixture of the two; The UV-curable EVA film suitable for electronic packaging has a thickness of 150-180 μm; Also included are polyethylene terephthalate and polyethylene protective films attached to the upper and lower surfaces of a UV-curable EVA adhesive film suitable for electronic packaging; A method for preparing a UV-curable EVA film suitable for electronic packaging, the preparation method comprising: Step S1: mixing EVA, a light diffuser, an antacid, an auxiliary agent and an organic solvent according to the raw material ratio by weight of a UV-curable EVA film suitable for electronic packaging; Step S2: adding the mixed material in step S1 into the hopper of a single screw extruder, performing melt mixing through the single screw extruder, and extruding through the die head of the single screw extruder, wherein each temperature section of the die head is 75° C.-90° C.; Step S3: After extrusion by the single screw extruder, the lower PET protective film and the UV-cured EVA film are pressed together by a hot press, and the surface of the lower PET protective film is textured by an embossing machine; Step S4: pressing and cooling the combined lower PET protective film and UV-cured EVA film by a casting roll; Step S5: Press the upper PE film, the lower PET protective film and the UV-cured EVA film together through a hot press; Step S6: trimming the upper PE film, the UV-cured EVA film and the lower PET protective film by a trimming machine; Step S7: Reeling the material through a reel; Step S8: taking out from the winder and packaging.

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