A two-component high-temperature resistant UV viscosity-reducing adhesive and its preparation method and application

Abstract

The present invention relates to the technical field of photocurable adhesives, particularly to the field of IPCC09J7, and more specifically to a two-component high-temperature resistant UV adhesive for reducing viscosity, as well as its preparation method and application. The UV adhesive for reducing viscosity comprises component A and component B; component A comprises an epoxy acrylate oligomer, an aliphatic acrylate oligomer, and a free radical type I photoinitiator; and component B comprises the following raw materials: an aliphatic polyisocyanate and a diluent. The epoxy acrylate oligomers are Miramer PE250 and Ebecryl 3708, with a weight ratio of Miramer PE250 to Ebecryl 3708 of 1:(1.1-1.8), which can reduce the peel strength of the adhesive after exposure to light and reduce the residual adhesive rate.

Description

Technical Field

[0001] The present invention relates to the technical field of light-curing adhesives, in particular to the field of IPCC09J7, and more specifically to a two-component high-temperature resistant UV viscosity-reducing adhesive and a preparation method and application thereof. Background Art

[0002] In recent years, with the rapid development of integrated semiconductor technology, the electronics industry has placed higher demands on pressure-sensitive adhesive products, and UV-based adhesives have emerged as one such product. As a process protection material, it provides adhesion during product processing, preventing movement, misalignment, and flying debris. After processing, the adhesive can be instantly de-sticked by ultraviolet light, allowing the product to be easily removed from the film. However, with the continuous refinement and streamlining of glass cover plate processes, higher requirements have been placed on UV-based adhesive films. Since most cutting methods use water jet cutting, which generates high heat, and single-crystal silicon materials also generate high heat during cutting, grinding, and thinning, the current market for UV-based adhesives has poor high-temperature resistance. After exposure to high temperatures, residual adhesive will form and the adhesive cannot be instantly de-sticked. Therefore, higher requirements have been placed on the high-temperature resistance of UV-based adhesives.

[0003] CN110484150A discloses a high-temperature resistant UV adhesive tape. The UV adhesive tape is made from the following raw materials by weight: 20-30 parts of a curing resin, 25-35 parts of methacrylic acid, 5-9 parts of 2-hydroxy-2-methyl-1-phenyl-1-propanone; 45-50 parts of methyl trimethylacetate, 45-55 parts of diethylene glycol monovinyl ether, 0.5-1 part of azobisisoheptonitrile, and 4-8 parts of trimethylolpropane crosslinker. After UV irradiation, the peel force can be reduced from the original 1600gf / 25mm to below 20gf / 25mm. The tape is pollution-free, residue-free, and not prone to precipitation. It can also withstand high temperatures of 150°C for one hour, significantly improving the initial tack of the adhesive and making it suitable for various coating methods. However, the peel force before irradiation is low (1600gf / 25mm) and does not decrease rapidly after irradiation (20gf / 25mm). Summary of the Invention

[0004] In response to the high-temperature resistance requirements of UV de-viscosity adhesive, the present invention provides a high-temperature resistant two-component UV de-viscosity adhesive for glass cover plate cutting and single-crystal silicon material cutting and grinding. The glue plays a supporting and protective role during the material processing process. It has a high adhesion force before illumination and can fix the adhered object so that it will not be displaced or damaged during the processing process. It can also withstand the heat generated during the processing. After illumination, it can be quickly de-adhesive and peeled off without any residual adhesive.

[0005] To achieve the purpose of the present invention, the first aspect of the present invention provides a two-component high-temperature resistant UV viscosity-reducing adhesive. The UV viscosity-reducing adhesive includes component A and component B; the component A includes an epoxy acrylate oligomer, an aliphatic acrylate oligomer, and a free radical type I photoinitiator; the component B includes the following raw materials: an aliphatic polyisocyanate and a diluent. The raw materials for preparing the component A also include an organic solvent.

[0006] Preferably, by weight percentage, the component A includes 6-15wt% of epoxy acrylate oligomer, 60-80wt% of aliphatic acrylate oligomer, 1-3wt% of free radical type I photoinitiator, and the balance is made up of organic solvent; the component B includes the following raw materials: 2-8wt% of aliphatic polyisocyanate, and 92-98wt% of diluent.

[0007] The epoxy acrylate oligomer is at least one of Ebecryl 3702, Ebecryl 3105, Ebecryl 3300, Ebecryl 3703, Ebecryl 3708, and Miramer PE250.

[0008] The applicant has found that when the functionality of the epoxy acrylate oligomer is 2-3 and the average viscosity is 3000-4500 cPs, it not only reduces the peel strength after light exposure, but also improves the high-temperature resistance of the viscosity-reducing adhesive. It is speculated that the epoxy group has a high reaction rate and acts together with the acrylate double bond to accelerate the volume shrinkage rate and quickly increase the glass transition temperature of the viscosity-reducing adhesive. Excessively high viscosity may affect the compatibility of the viscosity-reducing adhesive, requiring more solvent, which will affect the high-temperature resistance of the viscosity-reducing adhesive to a certain extent.

[0009] Preferably, the epoxy acrylate oligomer has a functionality of 2-3 and an average viscosity of 3000-4500 cPs.

[0010] Further preferably, the epoxy acrylate oligomer is Miramer PE250, which has a functionality of 2, an average viscosity of 3800 cPs (60° C.), and a number average molecular weight of 550, and Ebecryl 3708, which has a functionality of 2, an average viscosity of 3500 cPs (60° C.), and a number average molecular weight of 1500.

[0011] The applicants have further discovered that a weight ratio of Miramer PE250 to Ebecryl 3708 of 1:1.1-1.8 can reduce the peel strength of the viscosity-reducing adhesive after exposure to light, while also reducing the residual adhesive rate. It is speculated that the complementary end groups of epoxy acrylate oligomers with different molecular weights but similar viscosities allow the double bond freedom to assist in the reaction, thereby reducing the peel strength after exposure to light and providing high-temperature resistance. Excessive Ebecryl 3708, with its high molecular weight and low double bond freedom, may result in a slow reduction in peel strength after exposure to light. Excessive Miramer PE250 may also lead to residual adhesive in high-temperature environments. This may be due to the risk of free matter in high-temperature environments, which increases wettability with the substrate and alters interfacial interactions, thereby disrupting the overall structural cohesion and causing residual adhesive in high-temperature environments.

[0012] Preferably, the weight ratio of Miramer PE250 to Ebecryl 3708 is 1:(1.1-1.8).

[0013] Further preferably, the weight ratio of Miramer PE250 to Ebecryl 3708 is 1:1.51.

[0014] Preferably, the weight ratio of the epoxy acrylate oligomer to the aliphatic acrylate oligomer is 1:(5-8).

[0015] More preferably, the weight ratio of the epoxy acrylate oligomer to the aliphatic acrylate oligomer is 11.2:70.

[0016] Preferably, the organic solvent is toluene.

[0017] Preferably, the aliphatic polyisocyanate has a viscosity of 300-750 mPa·s (25° C.) and an isocyanate group content of 17-21 wt %.

[0018] More preferably, the aliphatic polyisocyanate has a viscosity of 500-600 mPa·s (25° C.) and an isocyanate group content of 18-21 wt %.

[0019] More preferably, the aliphatic polyisocyanate has a viscosity of 500 mPa.s (25° C.) and an isocyanate group content of 19.6 wt %, purchased from Guangzhou Haoyi New Materials Technology Co., Ltd., model Covestro N3390.

[0020] Preferably, the diluent is at least one of ethyl acetate, acetone, and butyl acetate.

[0021] More preferably, the diluent is ethyl acetate.

[0022] The applicant has discovered that when the free radical I photoinitiator is 1-hydroxycyclohexyl phenyl ketone and 2,4,6-trimethylbenzoyldiphenoxyphosphine, the peel strength after light exposure can be reduced. This may be because 2,4,6-trimethylbenzoyldiphenoxyphosphine has a high absorption efficiency in the 350nm-400nm range, which improves surface curing. To a certain extent, after the surface cures, the deep curing is insufficient. The addition of 1-hydroxycyclohexyl phenyl ketone, due to its lower absorption wavelength, accelerates the onset time and curing rate of the deep curing, improving the curing efficiency and enabling its application in thicker protective adhesive films used in the processing of glass single crystal silicon materials. Further research has found that when the weight ratio of 1-hydroxycyclohexyl phenyl ketone to 2,4,6-trimethylbenzoyldiphenoxyphosphine is 1: (0.5-0.8), the bonding performance can be improved. This may be because the combined initiator improves the dispersion performance and reduces the regional aggregation of small molecule initiators.

[0023] Preferably, the free radical type I photoinitiator is 1-hydroxycyclohexyl phenyl ketone and 2,4,6-trimethylbenzoyl diphenoxyphosphine, and the weight ratio of the 1-hydroxycyclohexyl phenyl ketone and 2,4,6-trimethylbenzoyl diphenoxyphosphine is 1:(0.5-0.8).

[0024] Further preferably, the free radical type I photoinitiator is 1-hydroxycyclohexyl phenyl ketone (CAS: 947-19-3) and 2,4,6-trimethylbenzoyl diphenoxy phosphine (CAS: 75980-60-8), and the weight ratio of 1-hydroxycyclohexyl phenyl ketone to 2,4,6-trimethylbenzoyl diphenoxy phosphine is 1.18:0.78.

[0025] Preferably, the weight average molecular weight of the aliphatic acrylate oligomer is 350,000-500,000.

[0026] More preferably, the weight average molecular weight of the aliphatic acrylate oligomer is 380,000-440,000.

[0027] More preferably, the weight average molecular weight of the aliphatic acrylate oligomer is 430,000.

[0028] Preferably, the raw materials for preparing the aliphatic acrylate oligomer include, by weight, 30-40 parts of a double bond-containing monomer, 0.05-0.5 parts of an auxiliary agent, and 45-75 parts of a solvent.

[0029] More preferably, the raw materials for preparing the aliphatic acrylate oligomer include, by weight, 37-40 parts of a double bond-containing monomer, 0.05-0.2 parts of an auxiliary agent, and 55-62 parts of a solvent.

[0030] More preferably, the raw materials for preparing the aliphatic acrylate oligomer include, by weight, 39.9 parts of double bond-containing monomers, 0.1 parts of auxiliary agents, and 60 parts of solvents.

[0031] The preparation of the aliphatic acrylate oligomer comprises the following steps:

[0032] S1, adding part of the solvent and heating to reflux temperature to obtain solution 1;

[0033] S2, adding the auxiliary agent and the double bond-containing monomer to the remaining solvent and mixing them uniformly to obtain solution 2;

[0034] S3, adding solution 2 dropwise to solution 1, heating in a water bath, and reacting after the addition is complete to obtain an aliphatic acrylate oligomer.

[0035] The temperature of the water bath is 75-90° C., and the reaction time is 3-5 h.

[0036] Preferably, the temperature of the water bath is 78° C., and the reaction time is 4 hours.

[0037] The double bond-containing monomers are isooctyl acrylate, acrylic acid, butyl acrylate, vinyl acetate, and N,N-dimethylacrylamide.

[0038] Preferably, the weight ratio of isooctyl acrylate, acrylic acid, butyl acrylate, vinyl acetate and N,N-dimethylacrylamide is 17:(2-5):(5-10):(5-10):(1-5).

[0039] Further preferably, the weight ratio of isooctyl acrylate (CAS: 29590-42-9), acrylic acid (CAS: 79-10-7), butyl acrylate (CAS: 141-32-2), vinyl acetate (CAS: 108-05-4), and N,N-dimethylacrylamide (CAS: 2680-03-7) is 17:4:10:6.5:2.4.

[0040] The solvents are ethyl acetate and acetone.

[0041] Preferably, the weight ratio of ethyl acetate to acetone is 1:(0.2-0.5).

[0042] Further preferably, the weight ratio of ethyl acetate to acetone is 23:7.

[0043] Preferably, the auxiliary agent is an initiator.

[0044] Preferably, the initiator is azobisisobutyronitrile (CAS: 78-67-1) and dibenzoyl peroxide (CAS: 94-36-0).

[0045] Preferably, the weight ratio of azobisisobutyronitrile to dibenzoyl peroxide is 1:(0.1-0.3).

[0046] Further preferably, the weight ratio of azobisisobutyronitrile to dibenzoyl peroxide is 4:1.

[0047] A second aspect of the present invention provides a method for preparing a two-component high-temperature resistant UV viscosity-reducing adhesive, comprising the following steps:

[0048] Step 1: Add epoxy acrylate oligomer, organic solvent, aliphatic acrylate oligomer in sequence,

[0049] Free radical type I photoinitiator, mixed uniformly to obtain the A component;

[0050] Step 2: Add aliphatic polyisocyanate to the diluent and mix well to obtain component B;

[0051] Step 3: Mix component A and component B.

[0052] Preferably, the mass percentage of component A in the viscosity-reducing rubber is 85-93 wt%.

[0053] Further preferably, the mass percentage of component A in the viscosity-reducing rubber is 91 wt%.

[0054] The third aspect of the present invention provides an application of a two-component high-temperature resistant UV viscosity-reducing adhesive, which is applied to at least one of a protective adhesive film for glass cover cutting, a protective adhesive film for single crystal silicon material processing, and a protective adhesive film for integrated circuits.

[0055] Preferably, the two-component high-temperature resistant UV viscosity-reducing adhesive is applied to a protective adhesive film for processing glass single crystal silicon materials.

[0056] Beneficial effects:

[0057] 1. The epoxy acrylate oligomer is Miramer PE250 and Ebecryl 3708, and the weight ratio of Miramer PE250 to Ebecryl 3708 is 1: (1.1-1.8), which can reduce the peel strength of the viscosity-reducing adhesive after light exposure and reduce the residual adhesive rate.

[0058] 2. The free radical type I photoinitiator is 1-hydroxycyclohexyl phenyl ketone and 2,4,6-trimethylbenzoyl diphenoxyphosphine. When the weight ratio of 1-hydroxycyclohexyl phenyl ketone and 2,4,6-trimethylbenzoyl diphenoxyphosphine is 1:(0.5-0.8), the peel strength after light irradiation can be reduced while the light bonding strength can be increased. DETAILED DESCRIPTION

[0059] Example 1

[0060] A two-component high-temperature resistant UV viscosity-reducing adhesive, the UV viscosity-reducing adhesive comprising a component A and a component B; in terms of weight percentage, the component A comprises 11.2 wt% of an epoxy acrylate oligomer, 70 wt% of an aliphatic acrylate oligomer, 2 wt% of a free radical type I photoinitiator, and 16.8 wt% of an organic solvent; the component B comprises the following raw materials: 5 wt% of an aliphatic polyisocyanate and 95 wt% of a diluent.

[0061] The epoxy acrylate oligomers are Miramer PE250, with a functionality of 2, an average viscosity of 3800 cPs (60° C.), and a number average molecular weight of 550, and Ebecryl 3708, with a functionality of 2, an average viscosity of 3500 cPs (60° C.), and a number average molecular weight of 1500.

[0062] The weight ratio of Miramer PE250 to Ebecryl 3708 is 1:1.51.

[0063] The organic solvent is toluene.

[0064] The aliphatic polyisocyanate has a viscosity of 500 mPa.s (25° C.) and an isocyanate group content of 19.6 wt %, and is purchased from Guangzhou Haoyi New Materials Technology Co., Ltd., model: Covestro N3390.

[0065] The diluent is ethyl acetate.

[0066] The weight average molecular weight (gel permeation chromatography) of the aliphatic acrylate oligomer is 430,000.

[0067] The raw materials for preparing the aliphatic acrylate oligomer include, by weight, 39.9 parts of a double-bond monomer, 0.1 parts of an auxiliary agent, and 60 parts of a solvent.

[0068] The double bond-containing monomers are isooctyl acrylate, acrylic acid, butyl acrylate, vinyl acetate, and N,N-dimethylacrylamide; the weight ratio of isooctyl acrylate (CAS: 29590-42-9), acrylic acid (CAS: 79-10-7), butyl acrylate (CAS: 141-32-2), vinyl acetate (CAS: 108-05-4), and N,N-dimethylacrylamide (CAS: 2680-03-7) is 17:4:10:6.5:2.4.

[0069] The solvents are ethyl acetate and acetone, and the weight ratio of ethyl acetate to acetone is 23:7.

[0070] The auxiliary agent is an initiator.

[0071] The initiator is azobisisobutyronitrile (CAS: 78-67-1) and dibenzoyl peroxide (CAS: 94-36-0); the weight ratio of the azobisisobutyronitrile to dibenzoyl peroxide is 4:1.

[0072] The preparation of the aliphatic acrylate oligomer comprises the following steps:

[0073] S1, adding 95 wt% of solvent and heating to reflux temperature to obtain solution 1;

[0074] S2, adding the auxiliary agent and the double bond-containing monomer to the remaining 15 wt % of the solvent and mixing them uniformly to obtain solution 2;

[0075] S3, add solution 2 dropwise to solution 1, control the addition to be complete over 30 minutes, heat in a water bath, and react.

[0076] Obtained aliphatic acrylate oligomers.

[0077] The temperature of the water bath was 78° C., and the reaction time was 4 h.

[0078] A method for preparing a two-component high-temperature resistant UV viscosity-reducing adhesive comprises the following steps:

[0079] Step 1: Add epoxy acrylate oligomer, organic solvent, aliphatic acrylate oligomer in sequence,

[0080] Free radical type I photoinitiator, mixed uniformly to obtain the A component;

[0081] Step 2: Add aliphatic polyisocyanate to the diluent and mix well to obtain component B;

[0082] Step 3: Mix component A with component B to obtain a viscosity-reducing adhesive.

[0083] The mass percentage of component A in the viscosity-reducing rubber is 91 wt%.

[0084] A two-component high-temperature resistant UV viscosity-reducing adhesive is used in protective adhesive films for processing glass single crystal silicon materials.

[0085] Comparative Example 1

[0086] The specific embodiment is the same as Example 1; except that the epoxy acrylate oligomer in Comparative Example 1 is Ebecryl 3708, which has a functionality of 2, an average viscosity of 3500 cPs (60° C.), and a number average molecular weight of 1550.

[0087] Comparative Example 2

[0088] The specific embodiment is the same as Example 1; the difference is that the epoxy acrylate oligomer in Comparative Example 2 is Miramer PE250, with a functionality of 2, an average viscosity of 3800 cPs (60° C.), and a number average molecular weight of 550.

[0089] Performance testing methods

[0090] The UV viscosity-reducing adhesive prepared by the above method was evenly mixed according to the ratio of component A and component B, and coated on the surface of a 50um PET substrate with a coater to a coating thickness of 10μm. The solvent was dried in an oven at 120°C for 90s, and the surface was covered with a release film. The film was then placed in an oven at 40°C for 72h for post-curing to obtain a UV viscosity-reducing film, and the performance test before light exposure was performed.

[0091] Light-induced viscosity reduction method: After curing, the product was cured under a mercury lamp with a curing energy of 400 mj / cm2. Post-illumination performance testing was performed. The test results are shown in Table 1.

[0092] Peel strength: Refer to GB / T 2792-2014 and test the peel strength before and after light exposure (gf / 25mm).

[0093] Adhesion retention (25°C): Refer to GB / T 4851-2014, ambient temperature 25°C, weight 1 kg, test the displacement (mm) of the UV adhesive reduction film after 72 hours of bonding.

[0094] High temperature resistance: The coated UV anti-viscosity film was attached to a stainless steel plate and placed in an oven at 180°C for 25 minutes. After cooling at 25°C for 60 minutes, the test was conducted: referring to GB / T 2792-2014, the peel strength (gf / 25mm) before and after light exposure was tested.

[0095] Adhesion retention (180°C): Refer to GB / T 4851-2014, ambient temperature 180°C, weight 1 kg, test the displacement (mm) of the UV adhesive reduction film after 4 hours of bonding.

[0096] Residual glue rate: Tested in accordance with GB / T 2792-2014.

[0097] Bonding effect with substrate: stick the adhesive surface on the stainless steel plate with a pressure of 10N, then peel off the adhesive surface from the stainless steel plate, repeat 3 times, and observe whether there is any adhesive loss and whether there are any patterns on the adhesive surface.

[0098] Performance test data

[0099] Table 1

[0100]

[0101]

Claims

1. A two-component high temperature resistant UV viscosity reducing adhesive, characterized in that: The UV viscosity-reducing adhesive comprises component A and component B; the component A comprises epoxy acrylate oligomer, aliphatic acrylate oligomer, and free radical type I photoinitiator; the component B comprises the following raw materials: aliphatic polyisocyanate, a diluent, and the raw materials for preparing the component A also include an organic solvent; The epoxy acrylate oligomer has a functionality of 2-3 and an average viscosity of 3000-4500 cPs; The epoxy acrylate oligomer is Miramer PE250 and Ebecryl 3708; the weight ratio of Miramer PE250 to Ebecryl 3708 is 1:(1.1-1.8); the weight ratio of the epoxy acrylate oligomer to the aliphatic acrylate oligomer is 1:(5-8); the free radical type I photoinitiator is 1-hydroxycyclohexyl phenyl ketone and 2,4,6-trimethylbenzoyldiphenoxyphosphine, and the weight ratio of 1-hydroxycyclohexyl phenyl ketone to 2,4,6-trimethylbenzoyldiphenoxyphosphine is 1:(0.5-0.8); the weight average molecular weight of the aliphatic acrylate oligomer is 350,000-500,000.

2. A two-component high temperature resistant UV viscosity reducing adhesive according to claim 1, characterized in that: The raw materials for preparing the aliphatic acrylate oligomer include, by weight, 30-40 parts of a double bond-containing monomer, 0.05-0.5 parts of an auxiliary agent, and 45-75 parts of a solvent.

3. A two-component high temperature resistant UV viscosity reducing adhesive according to claim 2, characterized in that: The preparation of the aliphatic acrylate oligomer comprises the following steps: S1, adding part of the solvent and heating to reflux temperature to obtain solution 1; S2, adding the auxiliary agent and the double bond-containing monomer to the remaining solvent and mixing them uniformly to obtain solution 2; S3, adding solution 2 dropwise to solution 1, heating in a water bath, and reacting after the addition is complete to obtain an aliphatic acrylate oligomer.

4. A two-component high temperature resistant UV viscosity reducing adhesive according to claim 3, characterized in that: The temperature of the water bath is 75-90° C., and the reaction time is 3-5 h.

5. A method for preparing the two-component high-temperature resistant UV viscosity-reducing adhesive according to any one of claims 1 to 4, characterized in that: The following steps are involved: Step 1: adding epoxy acrylate oligomer, organic solvent, aliphatic acrylate oligomer, and free radical type I photoinitiator in sequence, and mixing them evenly to obtain the A component; Step 2: Add aliphatic polyisocyanate to the diluent and mix well to obtain component B; Step 3: Mix component A and component B.

6. An application of the two-component high temperature resistant UV viscosity reducing adhesive according to claim 1, characterized in that: It is applied to at least one of the protective films for glass cover cutting, protective films for single crystal silicon material processing, and protective films for integrated circuits.

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