A UV anti-adhesive adhesive for MLCC cutting, a UV anti-adhesive tape, its preparation method and application

Abstract

This invention relates to a UV anti-adhesive adhesive, a UV anti-adhesive tape, and their preparation methods and applications for use in MLCC cutting. The preparation method of the UV anti-adhesive adhesive includes the following steps: S1, copolymerizing an acrylate-containing monomer with an aldehyde-ketone resin to form a hydroxyl-containing acrylate polymer; S2, reacting the hydroxyl-containing acrylate polymer from S1 with a compound containing isocyanate groups and carbon-carbon unsaturated bonds, controlling the molar ratio of -NCO in the isocyanate group and carbon-carbon unsaturated bond to -OH in the polymer in the reaction system to be (0.5–0.95):1. This invention, by copolymerizing the acrylate-containing monomer with an aldehyde-ketone resin, gives the hydroxyl-containing acrylate polymer an interpenetrating network molecular structure formed by the acrylic resin molecules and the aldehyde-ketone resin, thereby giving the UV anti-adhesive adhesive good hardness and creep resistance on the one hand, and good adhesion at 60–80°C on the other; furthermore, this UV anti-adhesive adhesive is easy to reduce tack, leaving almost no residue on the adhered object.

Description

Technical Field

[0001] This invention relates to a UV anti-adhesion adhesive, a UV anti-adhesion tape, and their preparation methods and applications that can be used for MLCC cutting. Background Technology

[0002] The manufacturing process of multilayer ceramic capacitors (MLCCs) includes: ① Casting: Coating ceramic paste onto a release film and drying it to obtain a green ceramic tape; ② Cutting: Cutting the blank into ceramic sheets of a certain size, each sheet becoming a layer of the multilayer ceramic substrate; ③ Punching: Punching holes in the green ceramic tape sheets, which will be filled with conductive adhesive in subsequent processing steps; ④ Filling: Filling the vias with via filler to create vertical pathways for circuit connections between layers, thus preparing vias inside the multilayer ceramic substrate; ⑤ Printing: Using screen printing, printing conductive paste or dielectric material onto the ceramic substrate. On the ceramic sheet, wires for electrical interconnection and printed components (resistors, capacitors, varistors, etc.) are made; ⑥ Stacking: The ceramic sheets with printed circuit patterns are stacked together in sequence to make the pattern meet the circuit structure requirements, and the release film from the printing is removed; ⑦ Static pressing: The stacked green ceramic sheets are bonded firmly using high pressure; ⑧ Cutting: The statically pressed ceramic sheets are cut according to the required requirements; ⑨ Picking: The cut components are collected; ⑩ Sintering: The cut products are placed in a sintering furnace and sintered into rakes, and then go through a series of subsequent processes to obtain the final product.

[0003] In the above-mentioned cutting process, in order to prevent the small components from falling or shifting and causing product defects, adhesive tape is needed to fix them during cutting. At this time, the adhesiveness of the tape is required to be high. After cutting, the small-sized components need to be collected. However, the strength of the green ceramic sheet itself is low at this time. When it is removed from the high-adhesion tape, it is easy to cause product damage and affect the picking efficiency.

[0004] Currently, the mainstream process uses heat-resistant adhesive tape. This type of tape has high tack at room temperature, providing effective adhesion during the cutting process. After cutting, heating to a certain temperature significantly reduces tack within a short time, facilitating pick-up. However, heat-resistant adhesive tape needs to be heated to a specific temperature to reduce tack (at least 90°C for 10-30 minutes). At this temperature, the surface of the raw ceramic wafer may become sticky, posing a risk of small components sticking together, leading to defects. Furthermore, the debonding time is long, affecting efficiency. Additionally, the adhesive layer of heat-resistant adhesive tape contains expanding particles, typically with a particle size of 10-30μm. To ensure a smooth adhesive surface and good bonding, the adhesive layer thickness is generally above 40μm. Excessive thickness increases the risk of tape deformation during cutting, potentially causing component skew and dimensional irregularities, leading to reduced yield. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a UV anti-adhesion adhesive, a UV anti-adhesion tape, and their preparation method and application that can be used for MLCC cutting.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A method for preparing a UV anti-tack adhesive for MLCC cutting includes the following steps:

[0008] S1. Copolymerize acrylate-containing monomers with aldehyde and ketone resins to produce hydroxyl-containing acrylate polymers;

[0009] S2. React the hydroxyl-containing acrylate polymer in S1 with a compound containing isocyanate groups and carbon-carbon unsaturated bonds, and control the molar ratio of -NCO in the compound containing isocyanate groups and carbon-carbon unsaturated bonds to -OH in the hydroxyl-containing acrylate polymer in the reaction system to be (0.5~0.95):1.

[0010] Preferably, the molar ratio of -NCO in the compound containing isocyanate groups and carbon-carbon unsaturated bonds to -OH in the hydroxyl-containing acrylate polymer in the reaction system is controlled to be (0.7-0.9):1, more preferably (0.8-0.9):1, for example 0.8:1, 0.82:1, 0.84:1, 0.86:1, 0.88:1 or 0.9:1, etc.

[0011] Preferably, the acrylate-containing monomer comprises the following structural formula: One or more of the compounds shown, along with acrylic acid, wherein R2 is selected from substituted or unsubstituted alkyl groups, and R3 is selected from H or methyl groups. The addition of acrylic acid can improve the adhesion of UV-resistant adhesives.

[0012] Furthermore, R2 is selected from alkyl groups having 1 to 6 carbon atoms, such as methyl, ethyl, propyl, butyl, etc.; the substituents include, but are not limited to, hydroxyl groups.

[0013] Furthermore, the aforementioned structural formula The compounds shown include one or more of butyl acrylate, methyl acrylate, ethyl acrylate, propyl acrylate, hydroxyethyl acrylate, and acrylic acid.

[0014] Furthermore, when the acrylate-containing monomers include butyl acrylate, methyl acrylate, and hydroxyethyl acrylate, the mass of butyl acrylate in the acrylate-containing monomers is greater than the mass of hydroxyethyl acrylate, which is greater than the mass of methyl acrylate, which is greater than the mass of acrylic acid.

[0015] In some embodiments, the mass ratio of butyl acrylate, methyl acrylate, hydroxyethyl acrylate and acrylic acid is 1:(0.15-0.25):(0.25-0.35):(0.08-0.18).

[0016] Preferably, the number average molecular weight of the aldehyde-ketone resin is 300-1000, more preferably 300-700, and even more preferably 350-450.

[0017] In some preferred embodiments, the aldehyde-ketone resin has an acid value ≤3 mgKOH / g, a hydroxyl value of 30–50 mgKOH / g, and a softening temperature of 80–95°C.

[0018] Preferably, the mass ratio of the acrylate-containing monomer to the aldehyde-ketone resin is (6-11):1, more preferably (6.5-10):1, for example 6.5:1, 7:1, 7.5:1, 8:1, 8.5:1, 9:1, 9.5:1, 10:1, etc.

[0019] Preferably, the carbon-carbon unsaturated bond in the compound containing isocyanate group and carbon-carbon unsaturated bond is a carbon-carbon double bond.

[0020] Furthermore, the compound containing isocyanate groups and carbon-carbon unsaturated bonds is selected from the following structural formulas.

[0021]

[0022] One or more of them, wherein R1 is selected from H or methyl.

[0023] Preferably, step S1 includes copolymerizing the acrylate-containing monomer and the aldehyde-ketone resin in the presence of an organic solvent and an initiator.

[0024] Further, the organic solvent includes one or more of benzene-based solvents, ester solvents, ketone solvents, and alkane solvents. For example, benzene-based solvents may be toluene, xylene, trimethylbenzene, tetramethylbenzene, etc.; ester solvents may be ethyl acetate, methyl acetate, butyl acetate, etc.; ketone solvents may be acetone, cyclohexanone, methyl ethyl ketone, etc.; and alkane solvents may be hexane, solvent oil, etc. Further, the initiator includes azo initiators and / or benzoyl peroxide, wherein the azo initiator includes, but is not limited to, azobisisobutyl cyanide.

[0025] In some preferred embodiments, step S1 specifically includes:

[0026] S1-1. Mix the acrylate-containing monomer, initiator, and a portion of the organic solvent to form a mixture;

[0027] S1-2. Add a portion of the mixture, aldehyde-ketone resin, and remaining organic solvent to the reactor, stir and heat to reflux, maintain reflux reaction, add the remaining mixture dropwise to the reaction system, and continue to maintain reflux reaction;

[0028] After the reactions in steps S1-3 and S1-2 are completed, a solvent is added while cooling to prepare the hydroxyl-containing acrylate polymer.

[0029] Furthermore, the organic solvent mentioned in step S1-1 above accounts for half or more of the total mass of the organic solvent, preferably 75% to 90%, such as 75%, 80%, 85% or 90%.

[0030] Furthermore, the portion of the mixture mentioned in steps S1-2 above accounts for half or less of the total mass or volume of the mixture, preferably 25% to 35%, such as 25%, 30%, 33% or 35%.

[0031] Preferably, the mass ratio of the acrylate-containing monomer to the initiator is 1:(0.001~0.01), for example, 1:0.001, 1:0.002, 1:0.004, 1:0.006, 1:0.008, etc.

[0032] Preferably, the mass ratio of the acrylate-containing monomer to the organic solvent is 1:(1.5-3.5), more preferably 1:(2-2.5), such as 1:2, 1:2.1, 1:2.2, 1:2.3, 1:2.4 or 1:2.5, etc.

[0033] Preferably, the solvent is the same as the organic solvent, and the mass ratio of the acrylate-containing monomer to the solvent is 1:(0.2-0.5), more preferably 1:0.2-0.4, for example 1:0.2, 1:0.25, 1:0.3, 1:0.35 or 1:0.4, etc.

[0034] Preferably, step S2 specifically includes reacting the hydroxyl-containing acrylate polymer with a compound containing isocyanate groups and carbon-carbon unsaturated bonds in the presence of an amine catalyst and / or an organometallic catalyst, controlling the reaction temperature at 40–60°C and the reaction time at 3–7 h.

[0035] Further, the amine catalyst includes one or more of N,N-dimethylcyclohexylamine, bis(2-dimethylaminoethyl) ether, and N-ethylmorpholine; the organometallic catalyst includes one or more of tin, bismuth, antimony, mercury, and zinc. As a preferred example, the organometallic catalyst includes one or more of stannous octoate, dibutyltin dilaurate, bismuth isooctanoate, bismuth laurate, bismuth neodecanoate, and bismuth naphthenate.

[0036] Further, the mass ratio of the amine catalyst and / or organometallic catalyst to the hydroxyl-containing acrylate polymer is (0.0001~0.001):1.

[0037] A second objective of this invention is to provide a UV-resistant adhesive for MLCC cutting prepared by the method described above.

[0038] The third objective of this invention is to provide a UV anti-adhesion tape, which sequentially comprises a base film, a dry adhesive formed from the UV anti-adhesion adhesive as described above, and a release film.

[0039] Preferably, the thickness of the dry adhesive is 5–40 μm.

[0040] More preferably, the thickness of the dry adhesive is 10–30 μm, and even more preferably 10–20 μm.

[0041] Preferably, the base film is selected from PET base film.

[0042] In some preferred embodiments, the UV anti-adhesion tape further includes a base coating layer disposed on the surface of the base film and located between the base film and the dry adhesive, the base coating layer being selected from a polyacrylate base coating layer or a polyurethane base coating layer.

[0043] Further, the total thickness of the base film and the undercoat is 25-200 μm, more preferably 50-150 μm, and even more preferably 75-125 μm.

[0044] Furthermore, the thickness of the base coating does not exceed 1 μm. In this invention, the release film is based on existing technology, and its thickness, material, etc., are not specifically limited.

[0045] Preferably, the dry adhesive is formed by adding a curing agent, a photoinitiator, and selectively adding a solvent to the UV-resistant adhesive, drying it at a first temperature, and curing it at a second temperature. In this invention, the solvent includes one or more of benzene-based solvents, ester-based solvents, ketone-based solvents, and alkane-based solvents, and will not be described further here.

[0046] Furthermore, the curing agent is selected from isocyanate curing agents and / or epoxy curing agents.

[0047] Furthermore, the curing agent is added at a mass of 0.01 to 0.5% of the UV-resistant adhesive, and even more specifically, at 0.05 to 0.15%.

[0048] Furthermore, the photoinitiator includes, but is not limited to, photoinitiator TPO and / or photoinitiator 184.

[0049] Furthermore, the mass of the photoinitiator is 1-5% of the UV-resistant adhesive, and even more specifically 1-3%, for example, 1%, 1.5%, 2%, 2.5%, 3%, etc.

[0050] Preferably, the first temperature is 70–120°C, and the drying time is 1–5 min.

[0051] Preferably, the second temperature is 40-60℃ and the curing time is ≥48h, such as 48h, 52h, 56h, 60h, etc.

[0052] Preferably, the UV-resistant adhesive tape has a peel strength of 1500–1900 g / inch at 180°C at room temperature and 750–900 g / inch at 60°C; the UV-resistant adhesive tape has a peel strength of no more than 4 g / inch at 180°C after UV irradiation at room temperature; the UV-resistant adhesive tape has a peel strength of no more than 4.5 g / inch at 180°C after being placed at 60°C for 20 minutes and then placed at room temperature for UV irradiation. Unless otherwise specified, UV irradiation refers to light irradiation with an energy ≥200 mJ / cm². 2 Furthermore, it is irradiated with UV light with a wavelength of 365nm.

[0053] A fourth objective of this invention is to provide a method for preparing the UV anti-adhesive tape as described above, comprising adding a curing agent, a photoinitiator, and selectively adding a solvent to the UV anti-adhesive tape to prepare a coating liquid, coating the coating liquid onto a base film, drying it at a first temperature, then attaching a release film to the surface of the coating liquid away from the base film, and finally curing it at a second temperature to prepare the UV anti-adhesive tape.

[0054] Preferably, the base film is a base film with an undercoat, which is commercially available.

[0055] A fifth object of the present invention is to provide an application of the UV anti-adhesive adhesive or the UV anti-adhesive tape as described above, including using the UV anti-adhesive adhesive or the UV anti-adhesive tape in MLCC, wafer, or substrate dicing processes. The wafer includes, but is not limited to, silicon wafers, alumina wafers, or silicon carbide wafers; the substrate includes, but is not limited to, ceramic substrates, glass substrates, or epoxy resin substrates.

[0056] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0057] This invention copolymerizes acrylate-containing monomers with aldehyde-ketone resins, resulting in a hydroxyl-containing acrylate polymer with an interpenetrating network molecular structure formed by acrylic resin molecules and aldehyde-ketone resins. This gives the UV anti-tack adhesive good hardness and creep resistance, preventing the adhesive layer from shifting during cutting and causing irregular dimensions of the cut elements. On the other hand, it has good adhesion at a temperature of 60-80°C, enabling it to firmly bond to the substrate. Furthermore, this UV anti-tack adhesive is easy to reduce tack, and leaves almost no adhesive residue on the substrate. Detailed Implementation

[0058] Although there are some UV anti-tack tapes on the market, they are mainly used in semiconductor cutting processes. The substrates they are applied to are mainly rigid materials such as wafers, glass, and resin substrates. They do not have good adhesion and anti-tack effects on green ceramic wafers. Furthermore, the UV anti-tack tapes on the market are mainly used for room temperature cutting. Their adhesion is low at high temperatures (60-80℃), which cannot meet the requirements of high-temperature cutting of MLCCs.

[0059] This invention copolymerizes acrylate-containing monomers with aldehyde-ketone resins, introducing aldehyde-ketone resins into the acrylic resin synthesis process. The resulting hydroxyl-containing acrylate polymer possesses an interpenetrating network molecular structure formed by acrylic resin molecules and aldehyde-ketone resins. This results in a UV anti-tack adhesive with excellent hardness and creep resistance, preventing creep displacement of the adhesive layer during cutting and thus avoiding irregular dimensions of the cut components. Simultaneously, the rubbery state of this hydroxyl-containing acrylate polymer shifts towards the high-temperature region, giving the tape good elastic modulus and pressure sensitivity at operating temperatures of 60-80°C. This allows for firm adhesion to the substrate at cutting temperatures, preventing relative displacement between the substrate and the tape due to blade pressure, which would affect cutting accuracy. In contrast, directly mixing aldehyde-ketone resins into acrylic resins can lead to problems. Small molecule aldehyde-ketone resins are easily released, which can affect the adhesion of the adhesive layer to the substrate when released at the adhesive layer-substrate interface, and cause unstable peel force when released to the adhesive layer surface, thus affecting the effectiveness of the UV anti-tack adhesive.

[0060] This invention also introduces UV-curable carbon-carbon unsaturated bonds (C=C bonds) by reacting hydroxyl-containing acrylate polymers with compounds containing isocyanate groups and carbon-carbon unsaturated bonds. After processing, when irradiated with UV light of a certain energy, the C=C double bonds in the adhesive tape rapidly add, resulting in a significant increase in the molecular weight and glass transition temperature of the adhesive tape, and a significant decrease in adhesion, making it easier to pick up MLCC components attached to the tape.

[0061] The UV-resistant tape made from the UV-resistant adhesive of this invention can quickly reduce tack under UV light irradiation, leaving almost no residue, and is suitable for MLCC cutting.

[0062] The present invention will be further described below with reference to embodiments. However, the present invention is not limited to the following embodiments. The implementation conditions used in the embodiments can be further adjusted according to different requirements of specific applications, and the implementation conditions not specified are conventional conditions in the industry. The technical features involved in the various embodiments of the present invention can be combined with each other as long as they do not conflict with each other.

[0063] Example 1

[0064] A method for preparing a UV-resistant adhesive tape includes the following steps:

[0065] (1) Mix 86.8g butyl acrylate, 16.6g methyl acrylate, 27.3g hydroxyethyl acrylate, 12g acrylic acid, 0.6g azobisisobutyronitrile and 280g ethyl acetate evenly to prepare a monomer mixture;

[0066] Add 50g ethyl acetate, 20g aldehyde-ketone resin (number average molecular weight 350-450; acid value ≤3mgKOH / g; hydroxyl value approximately 40mgKOH / g; softening temperature 80-95℃) and 1 / 3 of the monomer mixture to a four-necked flask, start stirring and heating, and start timing after reflux begins, maintaining reflux reaction for 30min; add the remaining monomer mixture dropwise over 2h; maintain reflux reaction for 2h; add 50g ethyl acetate while cooling to obtain acrylic resin 1.

[0067] (2) The acrylic resin 1 in (1) above is mixed with a compound containing isocyanate groups and carbon-carbon unsaturated bonds (2-isocyanoethyl acrylate) at a molar ratio of -NCO:-OH = 0.85:1. Dibutyltin dilaurate is added at a mass of 0.5‰ of the acrylic resin 1. The mixture is reacted at a constant temperature of 50°C for 5 hours. The content of -NCO groups is tested by potentiometric titration. The reaction is stopped when the conversion rate of -NCO groups is >99.5%, and UV anti-adhesive 1 is obtained.

[0068] (3) Add 0.1% by mass of isocyanate curing agent (Covestro, L-75) and 2% by mass of photoinitiator TPO to UV-reducing adhesive 1 in (2) above. Coat the adhesive with a 100μm base coat PET (polyacrylate base coat or polyurethane base coat, preferably polyurethane base coat, commercially available), dry to a thickness of 20μm, dry in an oven at 80℃ for 2min, attach release film, and then place in an oven at 50℃ for 48h to obtain tape sample 1.

[0069] Example 2

[0070] A method for preparing a UV-resistant adhesive tape includes the following steps:

[0071] (1) Mix 86.8g butyl acrylate, 16.6g methyl acrylate, 27.3g hydroxyethyl acrylate, 12g acrylic acid, 0.6g azobisisobutyronitrile and 280g ethyl acetate evenly to prepare a monomer mixture;

[0072] Add 50g ethyl acetate, 20g aldehyde-ketone resin (number average molecular weight 350-450; acid value ≤3mgKOH / g; hydroxyl value approximately 40mgKOH / g; softening temperature 80-95℃) and 1 / 3 of the monomer mixture to a four-necked flask, start stirring and heating, and start timing after reflux begins, maintaining reflux reaction for 30min; add the remaining monomer mixture dropwise over 2h; maintain reflux reaction for 2h; add 50g ethyl acetate while cooling to obtain acrylic resin 1.

[0073] (2) Acrylic resin 1 was mixed with a compound containing isocyanate groups and carbon-carbon unsaturated bonds (2-isocyanoethyl acrylate) at a ratio of -NCO:-OH = 0.9:1. Dibutyltin dilaurate was added at a mass of 0.5‰ of the mass of acrylic resin 1. The mixture was reacted at a constant temperature of 50℃ for 5 hours. The content of -NCO groups was tested by potentiometric titration. The reaction was stopped when the conversion rate of -NCO groups was >99.5%, and UV anti-adhesive 2 was obtained.

[0074] (3) Add 0.1% of the mass of UV-reducing adhesive 2 of isocyanate curing agent (Covestro, L-75) and 2% of the mass of UV-reducing adhesive 2 of photoinitiator TPO to UV-reducing adhesive 2. Coat the adhesive with a 100μm base coat PET (polyacrylate base coat or polyurethane base coat, preferably polyurethane base coat, commercially available), dry to a thickness of 20μm, dry in an oven at 80℃ for 2min, attach the release film, and then place it in an oven at 50℃ for 48h to obtain tape sample 2.

[0075] Example 3

[0076] A method for preparing a UV-resistant adhesive tape includes the following steps:

[0077] (1) Mix 86.8g butyl acrylate, 16.6g methyl acrylate, 27.3g hydroxyethyl acrylate, 12g acrylic acid, 0.6g azobisisobutyronitrile and 280g ethyl acetate evenly to prepare a monomer mixture;

[0078] Add 50g ethyl acetate, 15g aldehyde-ketone resin (number average molecular weight 350-450; acid value ≤3mgKOH / g; hydroxyl value approximately 40mgKOH / g; softening temperature 80-95℃) and 1 / 3 of the monomer mixture to a four-necked flask, start stirring and heating, and start timing after reflux begins, maintaining reflux reaction for 30min; add the remaining monomer mixture dropwise over 2h; maintain reflux reaction for 2h; add 40g ethyl acetate while cooling to obtain acrylic resin 2.

[0079] (2) Acrylic resin 2 was mixed with a compound containing isocyanate groups and carbon-carbon unsaturated bonds (2-isocyanoethyl acrylate) at a ratio of -NCO:-OH = 0.85:1. Dibutyltin dilaurate was added at a mass of 0.5‰ of the mass of acrylic resin 2. The mixture was reacted at a constant temperature of 50℃ for 5 hours. The content of -NCO groups was tested by potentiometric titration. The reaction was stopped when the conversion rate of -NCO groups was >99.5%, and UV anti-adhesive 3 was obtained.

[0080] (3) Add 0.1% of the mass of UV-reducing adhesive 3 of isocyanate curing agent (Covestro, L-75) and 2% of the mass of UV-reducing adhesive 3 of photoinitiator TPO to UV-reducing adhesive 3. Coat the adhesive with a 100μm base coat PET (polyacrylate or polyurethane base coat, preferably polyurethane base coat), dry to a thickness of 20μm, dry in an oven at 80℃ for 2min, attach the release film, and then place it in an oven at 50℃ for 48h to obtain tape sample 3.

[0081] Comparative Example 1

[0082] A method for preparing a UV-resistant adhesive tape includes the following steps:

[0083] (1) Mix 86.8g butyl acrylate, 16.6g methyl acrylate, 27.3g hydroxyethyl acrylate, 12g acrylic acid, 0.6g azobisisobutyronitrile and 280g ethyl acetate evenly to prepare a monomer mixture;

[0084] Add 50g ethyl acetate, 20g aldehyde-ketone resin (number average molecular weight 350-450; acid value ≤3mgKOH / g; hydroxyl value approximately 40mgKOH / g; softening temperature 80-95℃) and 1 / 3 of the monomer mixture to a four-necked flask, start stirring and heating, and start timing after reflux begins, maintaining reflux reaction for 30min; add the remaining monomer mixture dropwise over 2h; maintain reflux reaction for 2h; add 50g ethyl acetate while cooling to obtain acrylic resin 1.

[0085] (2) Acrylic resin 1 was mixed with a compound containing isocyanate groups and carbon-carbon unsaturated bonds (2-isocyanoethyl acrylate) at a ratio of -NCO:-OH = 0.45:1. Dibutyltin dilaurate was added at a mass of 0.5‰ of the mass of acrylic resin 1. The mixture was kept at 50°C for 5 hours. The content of -NCO groups was tested by potentiometric titration. The reaction was stopped when the conversion rate of -NCO groups was >99.5%, and UV anti-adhesive adhesive 4 was obtained.

[0086] (3) Add 0.1% of the mass of UV-reducing adhesive 4 to the UV-reducing adhesive 4, along with 2% of the mass of UV-reducing adhesive 4 to the UV-reducing adhesive 4, along with 2% of the mass of UV-reducing adhesive 4 to the UV-reducing adhesive 4, and coat it onto a 100μm thick PET base coat (polyacrylate or polyurethane base coat, preferably polyurethane base coat). The dry thickness is 20μm. Dry it in an oven at 80℃ for 2min, attach the release film, and then place it in an oven at 50℃ for 48h to obtain tape sample 4.

[0087] Comparative Example 2

[0088] A method for preparing a UV-resistant adhesive tape includes the following steps:

[0089] (1) Mix 86.8g butyl acrylate, 16.6g methyl acrylate, 27.3g hydroxyethyl acrylate, 12g acrylic acid, 0.6g azobisisobutyronitrile and 280g ethyl acetate evenly to prepare a monomer mixture;

[0090] Add 50g ethyl acetate, 15g aldehyde-ketone resin (number average molecular weight 350-450; acid value ≤3mgKOH / g; hydroxyl value approximately 40mgKOH / g; softening temperature 80-95℃) and 1 / 3 of the monomer mixture to a four-necked flask, start stirring and heating, and start timing after reflux begins, maintaining reflux reaction for 30min; add the remaining monomer mixture dropwise over 2h; maintain reflux reaction for 2h; add 40g ethyl acetate while cooling to obtain acrylic resin 2.

[0091] (2) Acrylic resin 2 and a compound containing isocyanate groups and carbon-carbon unsaturated bonds (2-isocyanoethyl acrylate) are mixed at a ratio of -NCO:-OH = 1:1. Dibutyltin dilaurate is added at a mass of 0.5‰ of the mass of acrylic resin 2. The mixture is reacted at a constant temperature of 50℃ for 5 hours. The content of -NCO groups is tested by potentiometric titration. The reaction is stopped when the conversion rate of -NCO groups is >99.5%, and UV anti-adhesive 5 is obtained.

[0092] (3) Add 0.1% by weight of isocyanate curing agent (Covestro, L-75) and 2% by weight of photoinitiator TPO to UV-reducing adhesive 5. Coat the adhesive with a 100μm base coat PET (polyacrylate or polyurethane base coat, preferably polyurethane base coat), dry to a thickness of 20μm, dry in an oven at 80℃ for 2min, attach release film, and then place in an oven at 50℃ for 48h to obtain tape sample 5.

[0093] Comparative Example 3

[0094] A method for preparing a UV-resistant adhesive tape includes the following steps:

[0095] (1) Mix 86.8g butyl acrylate, 16.6g methyl acrylate, 27.3g hydroxyethyl acrylate, 12g acrylic acid, 0.6g azobisisobutyronitrile and 280g ethyl acetate evenly to prepare a monomer mixture;

[0096] Add 50g of ethyl acetate and 1 / 3 of the monomer mixture to a four-necked flask, start stirring and heating, and start timing after reflux begins. Maintain reflux reaction for 30 minutes; add the remaining monomer mixture dropwise over 2 hours; maintain reflux reaction for 2 hours; add 4g of ethyl acetate while cooling to obtain acrylic resin 3.

[0097] (2) Acrylic resin 3 was mixed with a compound containing isocyanate groups and carbon-carbon unsaturated bonds (2-isocyanoethyl acrylate) at a ratio of -NCO:-OH = 0.85:1. Dibutyltin dilaurate was added at a mass of 0.5‰ of the mass of acrylic resin 3. The mixture was kept at a constant temperature of 50℃ for 5 hours. The content of -NCO groups was tested by potentiometric titration. The reaction was stopped when the conversion rate of -NCO groups was >99.5%, and UV anti-adhesive 6 was obtained.

[0098] (3) Add 0.1% by weight of isocyanate curing agent (Covestro, L-75) and 2% by weight of photoinitiator TPO to UV-reducing adhesive 6. Coat the adhesive with a 100μm base coat PET (polyacrylate or polyurethane base coat, preferably polyurethane base coat), dry to a thickness of 20μm, dry in an oven at 80℃ for 2min, attach release film, and then place in an oven at 50℃ for 48h to obtain tape sample 6.

[0099] Comparative Example 4

[0100] A method for preparing a UV-resistant adhesive tape includes the following steps:

[0101] (1) Mix 86.8g butyl acrylate, 16.6g methyl acrylate, 27.3g hydroxyethyl acrylate, 12g acrylic acid, 0.6g azobisisobutyronitrile and 280g ethyl acetate evenly to prepare a monomer mixture;

[0102] Add 50g of ethyl acetate and 1 / 3 of the monomer mixture to a four-necked flask, start stirring and heating, and start timing after reflux begins, maintaining reflux for 30 minutes; add the remaining monomer mixture dropwise over 2 hours; maintain reflux for 2 hours; while cooling, add 20g of aldehyde-ketone resin (number average molecular weight 350-450; acid value ≤3mgKOH / g; hydroxyl value approximately 40mgKOH / g; softening temperature 80-95℃) and 50g of ethyl acetate to obtain acrylic resin 4.

[0103] (2) Acrylic resin 4 was mixed with a compound containing isocyanate groups and carbon-carbon unsaturated bonds (2-isocyanoethyl acrylate) at a ratio of -NCO:-OH = 0.85:1. Dibutyltin dilaurate was added at a mass of 0.5‰ of the mass of acrylic resin 4. The mixture was kept at 50°C for 5 hours. The content of -NCO groups was tested by potentiometric titration. The reaction was stopped when the conversion rate of -NCO groups was >99.5%, and UV anti-adhesive adhesive 7 was obtained.

[0104] (3) Add 0.1% of the mass of UV-reducing adhesive 7 of isocyanate curing agent (Covestro, L-75) and 2% of the mass of UV-reducing adhesive 7 of photoinitiator TPO to UV-reducing adhesive 7, coat it on a 100μm base PET (polyacrylate or polyurethane base, preferably polyurethane base), dry to a thickness of 20μm, dry in an oven at 80℃ for 2min, attach the release film, and then place it in an oven at 50℃ for 48h to obtain tape sample 7.

[0105] The performance of the tape samples prepared in the above embodiments and comparative examples was tested, and the physical property test results of each tape sample are shown in Table 1 below.

[0106] Table 1

[0107]

[0108] The test method for 180° peel strength in Table 1 above refers to GB / T 2792-2014; "before UV" means without UV light irradiation, and "after UV" means after irradiation with light energy ≥200mj / cm. 2 And irradiation with UV light with a wavelength of 365nm.

[0109] Unless otherwise specified, in Table 1, "●" in the bonding effect indicates no abnormality, and "×" indicates that it is difficult to bond or there are air bubbles; "●" in the residual adhesive indicates that there is no residual adhesive on the surface of the object to be bonded before the UV peel test, and "×" indicates that there is residual adhesive on the surface of the object to be bonded before the UV peel test; "room temperature" refers to "25℃".

[0110] The inventors discovered that the adhesive strength of tape sample 7 became unstable with prolonged storage time or after heating, making it difficult to pick up small MLCC components (with particle sizes ranging from a few tenths of a millimeter to several millimeters) formed from the cutting process. The inventors speculate that this is most likely because the aldehyde-ketone resin did not form an interpenetrating network structure with the acrylic resin. Due to the small molecular weight of the aldehyde-ketone resin, it is easily released, resulting in unstable adhesive strength after heating or prolonged storage.

[0111] Each tape sample was used in the MLCC process, and the ceramic cutting displacement is shown in Table 2 below.

[0112] Table 2

[0113]

[0114] The displacement of the cut ceramic is obtained by measuring the changes in the length and width of the ceramic piece after the ceramic is cut. "●" represents: 0 ≤ length / width change ≤ 3mm, "△" represents: 3mm < length / width change ≤ 5mm, and "×" represents: 5mm < length / width change.

[0115] The results of picking up ceramic UV after cutting are shown in Table 3 below.

[0116] Table 3

[0117]

[0118] In this diagram, "●" indicates that all items were successfully picked up and there are no residual components on the tape; "△" indicates that the residual components on the tape are ≤0.5‰; and "×" indicates that the residual components on the tape are >0.5‰.

[0119] The residual adhesive after cutting ceramic pieces is shown in Table 4 below.

[0120] Table 4

[0121]

[0122] Unless otherwise specified, in Table 4, “●” indicates that the number of residual glue particles is ≤0.5‰, “△” indicates that 0.5‰ < the number of residual glue particles is ≤1‰, and “×” indicates that 1‰ < the number of residual glue particles.

[0123] The different types of ceramics listed in Tables 2 to 4 above can be purchased commercially.

[0124] The present invention has been described in detail above, with the aim of enabling those skilled in the art to understand and implement the invention. However, this description should not be construed as limiting the scope of protection of the invention. All equivalent changes or modifications made in accordance with the spirit and essence of the invention should be included within the scope of protection of the invention.

Claims

1. A method for preparing a UV anti-tack adhesive for MLCC cutting, characterized in that, The preparation method includes the following steps: S1. A hydroxyl-containing acrylate polymer is prepared by copolymerizing an acrylate-containing monomer with an aldehyde-ketone resin, wherein the acrylate-containing monomer is composed of acrylic acid and one or more acrylates selected from butyl acrylate, methyl acrylate, ethyl acrylate, propyl acrylate, and hydroxyethyl acrylate; the aldehyde-ketone resin has a number average molecular weight of 300-1000, an acid value ≤3 mgKOH / g, and a hydroxyl value of 30-50 mgKOH / g. S2. React the hydroxyl-containing acrylate polymer in S1 with a compound containing isocyanate groups and carbon-carbon unsaturated bonds, and control the molar ratio of -NCO in the compound containing isocyanate groups and carbon-carbon unsaturated bonds to -OH in the hydroxyl-containing acrylate polymer in the reaction system to be (0.5~0.95):

1.

2. The preparation method according to claim 1, characterized in that, The compounds containing isocyanate groups and carbon-carbon unsaturated bonds are selected from the following structural formulas. , , One or more of the compounds shown, wherein R1 is selected from H or methyl.

3. The preparation method according to claim 1, characterized in that, The mass ratio of the acrylate-containing monomer to the aldehyde-ketone resin is (6~11):1; and / or, When the acrylate-containing monomers include butyl acrylate, methyl acrylate and hydroxyethyl acrylate, the mass of butyl acrylate in the acrylate-containing monomers is greater than the mass of hydroxyethyl acrylate, which is greater than the mass of methyl acrylate, which is greater than the mass of acrylic acid.

4. The preparation method according to claim 1, characterized in that, Step S1 includes copolymerizing acrylate-containing monomers and aldehyde-ketone resins in the presence of an organic solvent and an initiator. The organic solvent includes one or more of benzene solvents, ester solvents, ketone solvents, and alkane solvents. The initiator includes azo initiators and / or benzoyl peroxide.

5. The preparation method according to claim 1, characterized in that, Step S1 specifically includes: S1-1. Mix the acrylate-containing monomer, initiator, and a portion of the organic solvent to form a mixture; S1-2. Add a portion of the mixture, aldehyde-ketone resin, and remaining organic solvent to the reactor, stir and heat to reflux, maintain reflux reaction, add the remaining mixture dropwise to the reaction system, and continue to maintain reflux reaction; After the reactions in steps S1-3 and S1-2 are completed, a solvent is added while cooling to prepare the hydroxyl-containing acrylate polymer.

6. The preparation method according to claim 4 or 5, characterized in that, The mass ratio of the acrylate-containing monomer to the initiator is 1:(0.001~0.01); and / or, The mass ratio of the acrylate-containing monomer to the organic solvent is 1:(1.5~3.5); and / or, The solvent is the same as the organic solvent, and the mass ratio of the acrylate-containing monomer to the solvent is 1:(0.2~0.5).

7. The preparation method according to claim 1, characterized in that, Step S2 specifically includes reacting the hydroxyl-containing acrylate polymer with a compound containing isocyanate groups and carbon-carbon unsaturated bonds in the presence of an amine catalyst and / or an organometallic catalyst, controlling the reaction temperature at 40~60℃ and the time at 3~7h.

8. A UV anti-tack adhesive for MLCC cutting, characterized in that, The UV-resistant adhesive is prepared by the preparation method according to any one of claims 1 to 7.

9. A UV anti-adhesive tape, characterized in that, The UV anti-adhesion tape comprises, in sequence, a base film, a dry adhesive formed by the UV anti-adhesion adhesive of claim 8, and a release film.

10. The UV anti-adhesion tape according to claim 9, characterized in that, The thickness of the dry adhesive is 5~40μm.

11. The UV anti-adhesion tape according to claim 9, characterized in that, The base film is selected from PET base film; and / or, The UV anti-adhesion tape also includes a base coating layer disposed on the surface of the base film and located between the base film and the dry adhesive. The base coating layer is selected from polyacrylate base coating layer or polyurethane base coating layer, and the total thickness of the base film and the base coating layer is 25~200μm.

12. The UV anti-adhesion tape according to claim 9, characterized in that, The dry adhesive is formed by adding a curing agent, a photoinitiator, and selectively adding a solvent to the UV-resistant adhesive, drying it at a first temperature, and curing it at a second temperature.

13. The UV anti-adhesion tape according to claim 12, characterized in that, The curing agent is selected from isocyanate curing agents and / or epoxy curing agents; and / or, The photoinitiator is photoinitiator TPO and / or photoinitiator 184; and / or, The first temperature is 70~120℃, and the drying time is 1~5 min; and / or, The second temperature is 40~60℃, and the curing time is ≥48h.

14. The UV anti-adhesion tape according to claim 9, characterized in that, The UV anti-adhesion tape has a peel strength of 1500~1900 g / inch at 180°C at room temperature and 750~900 g / inch at 60°C; the UV anti-adhesion tape has a peel strength of no more than 4 g / inch at 180°C after UV irradiation at room temperature; the UV anti-adhesion tape has a peel strength of no more than 4.5 g / inch at 180°C after being placed at 60°C for 20 minutes and then placed at room temperature for UV irradiation.

15. A method for preparing a UV anti-adhesive tape as described in any one of claims 9 to 14, characterized in that, The preparation method includes adding a curing agent, a photoinitiator, and selectively adding a solvent to the UV anti-adhesive to prepare a coating liquid, coating the coating liquid onto a base film, drying it at a first temperature, then attaching a release film to the surface of the coating liquid away from the base film, and finally curing it at a second temperature to prepare the UV anti-adhesive tape.

16. The application of the UV anti-adhesive adhesive as described in claim 8 or the UV anti-adhesive tape as described in any one of claims 9 to 14, characterized in that, The UV anti-tack adhesive or the UV anti-tack tape is used in MLCC, wafer or substrate cutting processes.

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