Hot-pressed epoxy adhesive composition as well as preparation method and application thereof

Abstract

The invention relates to a hot-pressed epoxy adhesive composition as well as a preparation method and application thereof. The hot-pressed epoxy adhesive composition comprises the following components in parts by weight: 30-50 parts of saturated polyester resin, 20-40 parts of epoxy resin, 0.1-5 parts of an epoxy curing agent and 20-60 parts of a solvent, the saturated polyester resin comprises hydroxyl type saturated polyester resin and carboxyl type saturated polyester resin. The adhesive tape prepared from the hot-pressed epoxy adhesive composition has high tensile shear strength and peel strength after being cured, and has excellent low temperature resistance and high temperature resistance.

Description

Technical Field

[0001] The invention relates to the technical field of epoxy adhesives, in particular to a hot-pressing epoxy adhesive composition. Background Art

[0002] At present, the battery pack products of new energy vehicles have higher and higher requirements for structural bonding. Both CCS insulation film and side panel insulation film need to be bonded quickly to achieve high productivity. Pressure-sensitive tape has become a product used for bonding. Pressure-sensitive tape is easy to use and can be bonded by applying a small amount of pressure. It can be directly bonded after die-cutting and can achieve continuous production with high bonding efficiency.

[0003] CN109233728A discloses an epoxy resin acrylate copolymer pressure-sensitive adhesive and a preparation method thereof. The epoxy resin acrylate copolymer pressure-sensitive adhesive is made of the following components by weight: 10 to 40 parts of hard monomer, 25 to 70 parts of soft monomer, 10 to 50 parts of epoxy resin, 0.2 to 1.8 parts of composite emulsifier, 0.2 to 2.5 parts of ammonium persulfate, 7 to 15 parts of isocyanate, an adjusted amount of acid-binding agent and a dispersion medium; the soft monomer is acrylic acid C 3 ~C 5 Ester; the hard monomer includes vinyl acetate; the composite emulsifier is composed of an ionic emulsifier and a non-ionic emulsifier; the acid binding agent is triethylamine, and the molar ratio of the acid binding agent to the ammonium persulfate is 1: (1.05-1.10); the dispersing medium has a resistivity of> 10 6 The epoxy resin acrylate copolymer pressure-sensitive adhesive provided by the technical solution has good bonding strength and lasting adhesion, high bonding strength with the substrate, and still has good peeling strength under heat.

[0004] CN111471145A discloses an emulsion type epoxy modified acrylate pressure sensitive adhesive and a preparation method and application thereof. The raw materials of the emulsion type epoxy modified acrylate pressure sensitive adhesive include the following components, and the content of each component is expressed in parts by weight as follows: 20-30 parts of epoxy resin, 4-8 parts of water-based epoxy emulsifier, 40-50 parts of soft monomer, 10-30 parts of hard monomer, 1-3 parts of cross-linking monomer, 0.1-0.2 parts of molecular weight regulator, 0.4-0.5 parts of initiator, 0.2-0.5 parts of sodium bicarbonate, 0.8-1.2 parts of anionic emulsifier and 1.8-2.2 parts of nonionic emulsifier; the emulsion type epoxy modified acrylate pressure sensitive adhesive provided by the technical scheme has good initial adhesion, lasting adhesion and peel strength, is resistant to high temperature, aging, plain and transparent, and is environmentally friendly.

[0005] However, the disadvantages of the pressure-sensitive adhesive tape in the prior art are that the tensile shear strength is usually weak, generally not exceeding 1 MPa, and the peel strength is generally not exceeding 3000 gf / 25 mm.

[0006] Therefore, there is a need to develop an adhesive and tape with higher tensile shear strength and peel strength. Summary of the invention

[0007] To solve the above technical problems, the present invention provides a hot-pressed epoxy adhesive composition, a preparation method and an application thereof. The tape made of the hot-pressed epoxy adhesive composition has high tensile shear strength and peel strength after curing, and has excellent low-temperature and high-temperature resistance.

[0008] To achieve this object, the present invention adopts the following technical solutions:

[0009] In a first aspect, the present invention provides a hot-pressed epoxy adhesive composition, comprising the following components in parts by weight: 30 to 50 parts (e.g., 32 parts, 34 parts, 36 parts, 38 parts, 40 parts, 42 parts, 44 parts, 46 parts, or 48 parts) of a saturated polyester resin, 20 to 40 parts (e.g., 22 parts, 24 parts, 26 parts, 28 parts, 30 parts, 32 parts, 34 parts, 36 parts, or 38 parts) of an epoxy resin, 0.1 to 5 parts (e.g., 0.5 parts, 1 parts, 1.5 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, or 4.5 parts) of an epoxy curing agent, and 20 to 60 parts (e.g., 25 parts, 30 parts, 35 parts, 40 parts, 45 parts, 50 parts, or 55 parts) of a solvent;

[0010] The saturated polyester resin includes a hydroxyl type saturated polyester resin and a carboxyl type saturated polyester resin.

[0011] In the present invention, the tape formed by the hot-pressing epoxy adhesive composition prepared by compounding components such as saturated polyester resin, epoxy resin, epoxy curing agent, etc. has no initial tack at room temperature, but has high tensile shear strength and peel strength after hot-pressing curing, as well as excellent low-temperature resistance and high-temperature resistance.

[0012] Preferably, the hydroxyl type saturated polyester resin comprises hydroxyl type saturated polyester resin A and hydroxyl type saturated polyester resin B.

[0013] Preferably, the acid value of the hydroxyl saturated polyester resin A is ≤2 mgKOH / g (for example, 0.3 mgKOH / g, 0.6 mgKOH / g, 0.9 mgKOH / g, 1.2 mgKOH / g, 1.5 mgKOH / g or 1.8 mgKOH / g, etc.), the hydroxyl value is 6 to 10 mgKOH / g (for example, 6.5 mgKOH / g, 7 mgKOH / g, 7.5 mgKOH / g, 8 mgKOH / g, 8.5 mgKOH / g, 9 mgKOH / g or 9.5 mgKOH / g, etc.), and the glass transition temperature is -20 to -10°C (for example, -19°C, -18°C, -17°C, -16°C, -15°C, -14°C, -13°C, -12°C or -11°C, etc.).

[0014] Preferably, the carboxyl saturated polyester resin has an acid value of 15 to 20 mgKOH / g (for example, 15.5 mgKOH / g, 16 mgKOH / g, 16.5 mgKOH / g, 17 mgKOH / g, 17.5 mgKOH / g, 18 mgKOH / g, 18.5 mgKOH / g, 19 mgKOH / g or 19.5 mgKOH / g, etc.), a hydroxyl value of ≤5 mgKOH / g (for example, 0.5 mgKOH / g, 1 mgKOH / g, 1.5 mgKOH / g, 2 mgKOH / g, 2.5 mgKOH / g, 3 mgKOH / g, 3.5 mgKOH / g, 4 mgKOH / g or 4.5 mgKOH / g, etc.), and a glass transition temperature of 20 to 50° C. (for example, 25° C., 30° C., 35° C., 40° C. or 45° C., etc.).

[0015] Preferably, the acid value of the hydroxyl saturated polyester resin B is ≤2 mgKOH / g (for example, 0.3 mgKOH / g, 0.6 mgKOH / g, 0.9 mgKOH / g, 1.2 mgKOH / g, 1.5 mgKOH / g or 1.8 mgKOH / g, etc.), the hydroxyl value is 6-10 mgKOH / g (for example, 6.5 mgKOH / g, 7 mgKOH / g, 7.5 mgKOH / g, 8 mgKOH / g, 8.5 mgKOH / g, 9 mgKOH / g or 9.5 mgKOH / g, etc.), and the glass transition temperature is 50-90° C. (for example, 55° C., 60° C., 65° C., 70° C., 75° C., 80° C. or 85° C., etc.);

[0016] In the present invention, the glass transition temperature of the hydroxyl saturated polyester resin A is preferably -20 to -10°C, and it is a soft amorphous polymer at room temperature, which mainly improves the adhesion to the substrate and helps to improve the toughness of the tape formed by the hot-pressed epoxy adhesive composition after hot-pressing curing. The acid value of the carboxyl saturated polyester resin is slightly higher, and the effect of the -COOH group on the metal material mainly includes the formation of coordination bonds and adsorption effects. Adding a carboxyl saturated polyester resin gives the hot-pressed epoxy adhesive composition formulation system a certain acid value, which can improve the adhesion to the metal plate; the glass transition temperature of the hydroxyl saturated polyester resin B is preferably 50 to 90°C, which is higher than room temperature. It is a hard solid state at room temperature, which helps to improve the hardness of the tape formed by the hot-pressed epoxy adhesive composition after hot-pressing curing, and improves the peel strength and shear strength.

[0017] Preferably, the weight proportion of the hydroxyl saturated polyester resin A is 22 to 26 parts (for example, 22.5 parts, 23 parts, 23.5 parts, 24 parts, 24.5 parts, 25 parts or 25.5 parts, etc.), the weight proportion of the carboxyl saturated polyester resin is 7 to 9 parts (for example, 7.2 parts, 7.4 parts, 7.6 parts, 7.8 parts, 8.0 parts, 8.2 parts, 8.4 parts, 8.6 parts or 8.8 parts, etc.), and the weight proportion of the hydroxyl saturated polyester resin B is 7 to 9 parts (for example, 7.2 parts, 7.4 parts, 7.6 parts, 7.8 parts, 8.0 parts, 8.2 parts, 8.4 parts, 8.6 parts or 8.8 parts, etc.).

[0018] Preferably, the epoxy resin includes epoxy resin A and / or epoxy resin B, and more preferably is a combination of epoxy resin A and epoxy resin B.

[0019] Preferably, the epoxy resin A and the epoxy resin B each independently include any one of bisphenol A epoxy resin, novolac epoxy resin, CTBN modified epoxy resin, benzaldehyde novolac resin, dimer acid modified epoxy resin or polyurethane modified epoxy resin or a combination of at least two thereof.

[0020] Preferably, the epoxy resin A comprises CTBN-modified bisphenol A epoxy resin, the epoxy equivalent of the CTBN-modified bisphenol A epoxy resin is 1000-1700 g / eq (for example, 1100 g / eq, 1200 g / eq, 1300 g / eq, 1400 g / eq, 1500 g / eq or 1600 g / eq, etc.), and the softening point is ≤100°C (for example, 10°C, 20°C, 30°C, 40°C, 50°C, 60°C, 70°C, 80°C or 90°C, etc.).

[0021] Preferably, the epoxy resin B comprises liquid bisphenol A epoxy resin, the epoxy equivalent of the liquid bisphenol A epoxy resin is 180-200 g / eq (for example, 182 g / eq, 184 g / eq, 186 g / eq, 188 g / eq, 190 g / eq, 192 g / eq, 194 g / eq, 196 g / eq or 198 g / eq, etc.), and the viscosity at 25°C is 10000-18000 cps (for example, 11000 cps, 12000 cps, 13000 cps, 14000 cps, 15000 cps, 16000 cps or 17000 cps, etc.).

[0022] Preferably, the mass ratio of the epoxy resin A to the epoxy resin B is (18-22):(8-12), for example, 19:9, 20:9, 21:9, 19:10, 20:10, 21:10, 19:11, 20:11 or 21:11, etc.

[0023] In the present invention, the epoxy resin A is preferably a CTBN-modified bisphenol A epoxy resin, i.e., an adduct of a solid bisphenol A epoxy resin and a carboxyl-terminated butadiene-acrylonitrile (CTBN) polymer, which can be used as a reactive toughener to achieve the effect of enhancing structural toughness in the system; the epoxy resin B is preferably a liquid bisphenol A epoxy resin, and the liquid bisphenol A epoxy resin has a low epoxy equivalent and is very rigid in the formulation system, that is, it can provide good shear strength. If only epoxy resin B is added to the epoxy resin in the system, the rigidity of the prepared hot-pressing epoxy adhesive composition after hot-pressing curing is very strong, the toughness is very poor, and there is no adhesion to polymer films such as PET, so that the true shear strength cannot be characterized. By adding epoxy resin A, the toughness of the tape made of the hot-pressing epoxy adhesive composition after hot-pressing curing is effectively improved, and the balance between toughness and rigidity is better achieved, thereby achieving a higher shear strength.

[0024] Preferably, the epoxy curing agent comprises a latent curing agent.

[0025] Preferably, the latent curing agent includes any one of an organic acid hydrazide curing agent, an aromatic polyamine curing agent, an acid anhydride curing agent or a dicyandiamide curing agent, or a combination of at least two thereof, and more preferably a dicyandiamide curing agent.

[0026] Preferably, the hot-pressed epoxy adhesive composition further comprises 0.5 to 5 parts by weight (eg, 1 part by weight, 1.5 parts by weight, 2 parts by weight, 2.5 parts by weight, 3 parts by weight, 3.5 parts by weight, 4 parts by weight or 4.5 parts by weight, etc.) of isocyanate curing agent.

[0027] Preferably, the isocyanate curing agent comprises aromatic polyisocyanate and / or aliphatic polyisocyanate.

[0028] Preferably, the hot-pressed epoxy adhesive composition further comprises 20 to 40 parts by weight (eg, 22 parts by weight, 24 parts by weight, 26 parts by weight, 28 parts by weight, 30 parts by weight, 32 parts by weight, 34 parts by weight, 36 parts by weight or 38 parts by weight, etc.) of filler.

[0029] Preferably, the filler comprises an inorganic filler and / or a flame retardant.

[0030] Preferably, the inorganic filler includes any one of boron nitride, silicon dioxide, aluminum oxide or superconducting carbon fiber, or a combination of at least two thereof.

[0031] Preferably, the flame retardant includes any one of hypophosphite, diphenyl phosphate, aluminum hydroxide or diethylaluminum hypophosphite, or a combination of at least two thereof, and hypophosphite is more preferred.

[0032] Preferably, the hypophosphite comprises diethylaluminum hypophosphite.

[0033] Preferably, the D50 particle size of the diethyl aluminum hypophosphite is 3 to 6 μm, and the D100 particle size is 13 to 22 μm (for example, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, 20 μm or 21 μm, etc.).

[0034] In the present invention, the D100 particle size of the diethyl aluminum hypophosphite is preferably 13 to 22 μm. When the D100 particle size of the diethyl aluminum hypophosphite is greater than 22 μm, it is easy to cause a poor film formed by the hot-pressed epoxy adhesive composition, and the film surface has obvious granularity, which affects the performance.

[0035] Preferably, the solvent includes any one of butanone, isopropanol, ethyl acetate or toluene, or a combination of at least two thereof, and more preferably ethyl acetate and / or butanone.

[0036] In a second aspect, the present invention provides a method for preparing the hot-pressed epoxy adhesive composition as described in the first aspect, the preparation method comprising the following steps: mixing a saturated polyester resin, an epoxy resin, an epoxy curing agent and a solvent to obtain the hot-pressed epoxy adhesive composition.

[0037] Preferably, the mixing further comprises mixing with an isocyanate curing agent.

[0038] Preferably, the mixing further comprises mixing with a filler.

[0039] In a third aspect, the present invention provides an adhesive tape, comprising an epoxy adhesive layer, wherein the epoxy adhesive layer is prepared from the hot-pressed epoxy adhesive composition as described in the first aspect.

[0040] Preferably, the single-sided tape comprises a release layer, an epoxy adhesive layer and a substrate layer which are stacked in sequence.

[0041] Preferably, the double-sided tape comprises a first release layer, a first epoxy adhesive layer, a substrate layer, a second epoxy adhesive layer and a second release layer which are stacked in sequence.

[0042] Preferably, the substrate-free adhesive tape comprises a first release layer, an epoxy adhesive layer and a second release layer which are stacked in sequence.

[0043] Preferably, the release layer in the single-sided tape, the first release layer and the second release layer in the double-sided tape, and the first release layer and the second release layer in the substrate-free tape each independently comprise a single-sided silicon-coated release film or a double-sided silicon-coated release film.

[0044] Preferably, the substrate layer includes any one of a PET film, a PI film or a metal foil.

[0045] Compared with the prior art, the present invention has at least the following beneficial effects:

[0046] In the present invention, the adhesive tape formed by the hot-pressed epoxy adhesive composition prepared by compounding components such as saturated polyester resin, epoxy resin, epoxy curing agent, etc. has no initial tack at room temperature, but has high tensile shear strength and peel strength after hot pressing curing, and excellent low-temperature and high-temperature resistance. The single-sided adhesive tape made of the hot-pressed epoxy adhesive composition provided by the present invention has a room temperature peel strength of ≥3000gf / 25mm, a 60°C peel strength of ≥1650gf / 25mm, a -20°C peel strength of ≥1650gf / 25mm, and a tensile shear strength of ≥8MPa. Preferably, the room temperature peel strength is ≥5000gf / 25mm, the 60°C peel strength is ≥2500gf / 25mm, the -20°C peel strength is ≥2500gf / 25mm, and the tensile shear strength is ≥10MPa. The flame retardancy can reach VTM-0, and the flame retardancy is good. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 A schematic diagram of the structure of the single-sided adhesive tape provided in Example 1;

[0048] 1-release layer; 2-epoxy adhesive layer 3-substrate layer. DETAILED DESCRIPTION

[0049] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and through specific implementation methods. However, the following examples are only simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the claims.

[0050] The components used in the following examples and comparative examples are as follows:

[0051] Hydroxyl type saturated polyester resin A: BX1001 produced by Toyobo Co., Ltd., acid value <2 mgKOH / g, hydroxyl value = 8 mgKOH / g, glass transition temperature -18°C.

[0052] Carboxyl type saturated polyester resin: Toyobo Co., Ltd. GW6210, acid value = 16 mgKOH / g, hydroxyl value = 4 mgKOH / g, glass transition temperature 34°C

[0053] Hydroxyl type saturated polyester resin B: GK888 produced by Toyobo Co., Ltd., acid value <2 mgKOH / g, hydroxyl value = 8 mgKOH / g, glass transition temperature 87°C.

[0054] Epoxy resin A: Huntsman solid CTBN modified epoxy resin, RK 84L, epoxy equivalent, 1250 ~ 1500g / eq, softening point less than 100 ℃.

[0055] Epoxy resin B: Nan Ya bisphenol A epoxy resin, NPEL-128, epoxy equivalent, 185-186.6 g / eq, viscosity at 25° C. is 12000-15000 cps.

[0056] Aromatic polyisocyanates : Covestro L-75, the mass percentage of NCO group is 13.0%.

[0057] Aliphatic polyisocyanates : Covestro N3900, the mass percentage of NCO group is 23.5%.

[0058] Dicyandiamide curing agent: Lepcu DDH 5850 from Complex Hi-Tech, particle size ≤ 10μm, purity ≥95%.

[0059] Example 1

[0060] The present embodiment provides a hot-pressed epoxy adhesive composition, a preparation method thereof, and a single-sided tape. The hot-pressed epoxy adhesive composition includes the following components in parts by weight: 24 parts of a hydroxyl-type saturated polyester resin A, 8 parts of a carboxyl-type saturated polyester resin, 8 parts of a hydroxyl-type saturated polyester resin B, 20 parts of an epoxy resin A, 10 parts of an epoxy resin B, 1.9 parts of an isocyanate curing agent (aromatic polyisocyanate), 1.5 parts of an epoxy curing agent (dicyandiamide curing agent), 30 parts of a flame retardant (diethylaluminum hypophosphite, D50 particle size is 3 μm, D100 particle size is 22 μm), and 40 parts of a solvent (butanone).

[0061] The preparation method of the hot-pressed epoxy adhesive composition comprises the following steps: stirring and mixing hydroxyl-type saturated polyester resin A, carboxyl-type saturated polyester resin, hydroxyl-type saturated polyester resin B, epoxy resin A, epoxy resin B, isocyanate curing agent, epoxy curing agent, filler and solvent in a stirring barrel to obtain the hot-pressed epoxy adhesive composition.

[0062] The single-sided tape, such as Figure 1 As shown, it includes a release layer 1, an epoxy adhesive layer 2 and a substrate layer 3 which are stacked in sequence, and is prepared by the following method: the above-mentioned hot-pressed epoxy adhesive composition is coated on a 100 μm PET film, and dried at 120°C for 1.5 minutes to form an epoxy adhesive layer with a thickness of 30 μm, which is then laminated and rolled up with a single-sided silicon-coated release film to obtain the single-sided tape.

[0063] Example 2

[0064] The present embodiment provides a hot-pressed epoxy adhesive composition, a preparation method thereof, and a single-sided adhesive tape. The only difference between the hot-pressed epoxy adhesive composition and the embodiment 1 is that the hot-pressed epoxy adhesive composition includes the following components in parts by weight: 22 parts of a hydroxyl-type saturated polyester resin A, 9 parts of a carboxyl-type saturated polyester resin, 9 parts of a hydroxyl-type saturated polyester resin B, 22 parts of an epoxy resin A, 8 parts of an epoxy resin B, 1.1 parts of an isocyanate curing agent (aliphatic polyisocyanate), 1.3 parts of an epoxy curing agent (dicyandiamide curing agent), 30 parts of a flame retardant (diethylaluminum hypophosphite, D50 particle size is 3 μm, D100 particle size is 22 μm) and 40 parts of a solvent (methyl ethyl ...

[0065] Example 3

[0066] The present embodiment provides a hot-pressed epoxy adhesive composition, a preparation method thereof, and a single-sided tape. The only difference between the hot-pressed epoxy adhesive composition and the embodiment 1 is that the hot-pressed epoxy adhesive composition includes the following components in parts by weight: 26 parts of hydroxyl saturated polyester resin A, 7 parts of carboxyl saturated polyester resin, 7 parts of hydroxyl saturated polyester resin B, 18 parts of epoxy resin A, 12 parts of epoxy resin B, 1.9 parts of isocyanate curing agent (aromatic polyisocyanate), 1.7 parts of epoxy curing agent (dicyandiamide curing agent), 30 parts of flame retardant (diethyl aluminum hypophosphite, D50 particle size is 3 μm, D100 particle size is 22 μm) and 40 parts of solvent (butanone), and other conditions are the same as those in the embodiment 1.

[0067] Example 4

[0068] This embodiment provides a hot-pressed epoxy adhesive composition, a preparation method thereof, and a single-sided tape. The only difference between this embodiment and Embodiment 1 is that the weight fraction of the hydroxyl-type saturated polyester resin A is adjusted to 18 parts, the weight fractions of the carboxyl-type saturated polyester resin and the hydroxyl-type saturated polyester resin are both adjusted to 11 parts, and the other conditions are the same as those in Embodiment 1.

[0069] Example 5

[0070] This embodiment provides a hot-pressed epoxy adhesive composition, a preparation method thereof, and a single-sided tape. The only difference between this embodiment and Embodiment 1 is that the weight fraction of the hydroxyl-type saturated polyester resin A is adjusted to 30 parts, the weight fractions of the carboxyl-type saturated polyester resin and the hydroxyl-type saturated polyester resin are both adjusted to 5 parts, and the other conditions are the same as those in Embodiment 1.

[0071] Example 6

[0072] This embodiment provides a hot-pressed epoxy adhesive composition, a preparation method thereof, and a single-sided tape. The only difference between this embodiment and Example 1 is that the flame retardant (diethylaluminum hypophosphite, D50 particle size is 3 μm, D100 particle size is 22 μm) is adjusted to 30 parts of the same mass of inorganic filler (silicon dioxide, D50 particle size is 3 μm, D100 particle size is 18 μm), and other conditions are the same as those in Example 1.

[0073] Example 7

[0074] This embodiment provides a hot-pressed epoxy adhesive composition, a preparation method thereof, and a single-sided tape. The only difference between this embodiment and Example 1 is that the flame retardant (diethylaluminum hypophosphite, D50 particle size is 3 μm, D100 particle size is 22 μm) is adjusted to 30 parts of the same mass of the flame retardant (diphenyl phosphate), and other conditions are the same as those in Example 1.

[0075] Example 8

[0076] This embodiment provides a hot-pressed epoxy adhesive composition, a preparation method thereof, and a single-sided tape. The difference between this embodiment and embodiment 1 is that no isocyanate curing agent (aromatic polyisocyanate) is added, and other conditions are the same as those in embodiment 1.

[0077] Example 9

[0078] This embodiment provides a hot-pressed epoxy adhesive composition, a preparation method thereof, and a single-sided tape. The difference between this embodiment and embodiment 1 is that epoxy resin B is not added, the weight fraction of epoxy resin A is adjusted to 30 parts, and other conditions are the same as those in embodiment 1.

[0079] Example 10

[0080] This embodiment provides a hot-pressed epoxy adhesive composition, a preparation method thereof, and a single-sided tape. The difference between this embodiment and embodiment 1 is that epoxy resin A is not added, the weight fraction of epoxy resin B is adjusted to 30 parts, and other conditions are the same as those in embodiment 1.

[0081] Embodiment 11

[0082] This embodiment provides a hot-pressed epoxy adhesive composition, a preparation method thereof, and a single-sided tape. The only difference between this embodiment and Embodiment 1 is that the weight fraction of epoxy resin A is adjusted to 15 parts, and the weight fraction of epoxy resin B is adjusted to 15 parts. Other conditions are the same as those in Embodiment 1.

[0083] Example 12

[0084] This embodiment provides a hot-pressed epoxy adhesive composition, a preparation method thereof, and a single-sided tape. The difference between this embodiment and Embodiment 1 is that no carboxyl-type saturated polyester resin is added, and the weight fraction of hydroxyl-type saturated polyester resin B is adjusted to 16 parts. Other conditions are the same as those in Embodiment 1.

[0085] Embodiment 13

[0086] This embodiment provides a hot-pressed epoxy adhesive composition, a preparation method thereof, and a single-sided tape. The difference between this embodiment and Embodiment 1 is that the hydroxyl-type saturated polyester resin B is not added, the weight fraction of the carboxyl-type saturated polyester resin is adjusted to 16 parts, and other conditions are the same as those in Embodiment 1.

[0087] Embodiment 14

[0088] The present embodiment provides a hot-pressed epoxy adhesive composition, a preparation method thereof, and a single-sided adhesive tape. The only difference between the hot-pressed epoxy adhesive composition and the embodiment 1 is that the hot-pressed epoxy adhesive composition includes the following components in parts by weight: 30 parts of a hydroxyl-type saturated polyester resin A, 15 parts of a carboxyl-type saturated polyester resin, 5 parts of a hydroxyl-type saturated polyester resin B, 20 parts of an epoxy resin A, 20 parts of an epoxy resin B, 1.9 parts of an isocyanate curing agent (aromatic polyisocyanate), 1.5 parts of an epoxy curing agent (dicyandiamide curing agent), 40 parts of a flame retardant (diethylaluminum hypophosphite, D50 particle size is 3 μm, D100 particle size is 22 μm) and 60 parts of a solvent (methyl ethyl ...

[0089] Embodiment 15

[0090] The present embodiment provides a hot-pressed epoxy adhesive composition, a preparation method thereof, and a single-sided tape. The only difference between the hot-pressed epoxy adhesive composition and the embodiment 1 is that the hot-pressed epoxy adhesive composition includes the following components in parts by weight: 18 parts of hydroxyl saturated polyester resin A, 8 parts of carboxyl saturated polyester resin, 4 parts of hydroxyl saturated polyester resin B, 10 parts of epoxy resin A, 10 parts of epoxy resin B, 1.9 parts of isocyanate curing agent (aromatic polyisocyanate), 1.5 parts of epoxy curing agent (dicyandiamide curing agent), 20 parts of flame retardant (diethyl aluminum hypophosphite, D50 particle size is 3 μm, D100 particle size is 22 μm) and 20 parts of solvent (butanone), and other conditions are the same as those in the embodiment 1.

[0091] Comparative Example 1

[0092] This comparative example provides a hot-pressed epoxy adhesive composition, a preparation method thereof, and a single-sided tape, which differs from Example 1 only in that no carboxyl-type saturated polyester resin and hydroxyl-type saturated polyester resin are added, the weight fraction of hydroxyl-type saturated polyester resin A is adjusted to 40 parts, and other conditions are the same as those in Example 1.

[0093] Comparative Example 2

[0094] This comparative example provides a hot-pressed epoxy adhesive composition, a preparation method thereof, and a single-sided tape, which differs from Example 1 only in that epoxy resin A, epoxy resin B, and epoxy curing agent are not added, and other conditions are the same as those in Example 1.

[0095] Comparative Example 3

[0096] This comparative example provides a hot-pressed epoxy adhesive composition, a preparation method thereof, and a single-sided tape. The difference between the comparative example and Example 1 is that no epoxy curing agent is added, and other conditions are the same as those of Example 1.

[0097] The single-sided adhesive tapes provided in Examples 1 to 15 and Comparative Examples 1 to 3 were subjected to the following performance tests.

[0098] Peel strength: The single-sided tape was cut into 25mm×100mm sheets, the release layer was removed, the epoxy adhesive layer was adsorbed on the aluminum plate, and hot pressed at a pressure of 1MPa and a temperature of 170℃ for 20min. After standing for 24 hours, it was placed in an environment of 23℃, 60℃, -20℃ and 50%RH for 30 minutes. The peel strength test was carried out in accordance with GB / T 2792-2014 "Test method for peel strength of adhesive tape", and the room temperature peel strength, 60℃ peel strength, and -20℃ peel strength were obtained respectively. The room temperature peel strength ≥3000gf / 25mm, the 60℃ peel strength ≥1650gf / 25mm, and the -20℃ peel strength ≥1650gf / 25mm were regarded as qualified.

[0099] Tensile shear strength: Cut the single-sided tape into 25mm×12.5mm pieces, remove the release layer and stick the epoxy adhesive layer to one end of a 25mm×100mm 3003 aluminum plate, press it with a pressure of 1MPa and a temperature of 170℃ for 20min, and then place it in an environment of 23℃ and 50%RH for 24 hours. Then take the structural adhesive PU2020 and evenly apply it on the surface of the substrate layer of the single-sided tape, and use a dovetail clamp to stick another 25mm×100mm 3003 aluminum plate on it, and then place it in an environment of 23℃ and 50%RH for 7 days. After completion, perform the tensile shear strength test in accordance with GB / T 7124-2008 "Test method for tensile shear strength of adhesives". The tensile shear strength is ≥8MPa, which is considered qualified.

[0100] Flame retardant performance: tested in accordance with UL94-2013 (R-2021) "Vertical Burning Test for Film Materials", where the flame retardant grades are VTM-0, VTM-1 and VTM-2.

[0101] The test results are shown in Table 1 below.

[0102] Table 1

[0103]

[0104]

[0105] In Table 1, “None” means that the three levels of flame retardancy, VTM-0, VTM-1 and VTM-2, are not achieved, that is, the flame retardancy is not achieved.

[0106] From the test results in Table 1, it can be seen that the room temperature peel strength of the single-sided tape provided in Examples 1-15 is ≥3000 gf / 25mm, the 60°C peel strength is ≥1650 gf / 25mm, the -20°C peel strength is ≥1650 gf / 25mm, and the tensile shear strength is ≥8 MPa.

[0107] Compared with Example 1, if the weight fraction of the hydroxyl type saturated polyester resin A is too small (Example 4), the room temperature peel strength and -20°C peel strength of the obtained single-sided tape are greatly reduced, and the tensile shear strength is reduced; if the weight fraction of the hydroxyl type saturated polyester resin A is too large (Example 5), the room temperature peel strength and 60°C peel strength are greatly reduced, and the tensile shear strength is reduced. It can be seen that the weight fraction of the hydroxyl type saturated polyester resin A is 22 to 26 parts, the weight fraction of the carboxyl type saturated polyester resin is 7 to 9 parts, and the weight fraction of the hydroxyl type saturated polyester resin B is 7 to 9 parts, and the performance of the tape made from the obtained hot pressing epoxy adhesive composition is better.

[0108] Compared with Example 1, if diethyl aluminum hypophosphite is replaced with diphenyl phosphate of the same mass (Example 7), the flame retardant properties of the obtained single-sided tape are reduced to VTM-2, and the mechanical properties are reduced, because diphenyl phosphate easily destroys the cohesion of the epoxy adhesive layer, and the low phosphorus content leads to poor flame retardant properties. It can be seen that the hot-pressed epoxy adhesive composition prepared by using diethyl aluminum hypophosphite as a flame retardant has better performance as a tape.

[0109] Compared with Example 1, if the isocyanate curing agent is not added (Example 8), the saturated polyester resin cannot achieve network crosslinking, and the mechanical properties of the obtained single-sided tape are reduced. It can be seen that the hot-pressed epoxy adhesive composition prepared by adding an isocyanate curing agent has better performance as a tape.

[0110] Compared with Example 1, if epoxy resin B is not added (Example 9), the high temperature resistance of the obtained single-sided tape is relatively low; if epoxy resin A is not added (Example 10), the low temperature resistance of the obtained single-sided tape is relatively low. It can be seen that the hot-pressed epoxy adhesive composition prepared by compounding epoxy resin A and epoxy resin B has better performance in making a tape.

[0111] Compared with Example 1, if the carboxyl type saturated polyester resin (Example 12) or the hydroxyl type saturated polyester resin B (Example 13) is not added, the mechanical properties of the obtained single-sided tape are reduced. It can be seen that the hot-pressed epoxy adhesive composition prepared by compounding hydroxyl type saturated polyester resin A, carboxyl type saturated polyester resin and hydroxyl type saturated polyester resin B has better performance.

[0112] Compared with Example 1, if the saturated polyester resin is only hydroxyl-type saturated polyester resin A (Comparative Example 1), the prepared single-sided tape has poor high temperature resistance and low 60° C. peel strength, which cannot meet the requirements.

[0113] Compared with Example 1, if the epoxy resin and the epoxy curing agent are not added (Comparative Example 2), the tensile shear strength of the prepared single-sided tape is low and cannot meet the requirements.

[0114] Compared with Example 1, if the epoxy curing agent is not added (Comparative Example 3), the tensile shear strength of the prepared single-sided tape is low and cannot meet the requirements.

[0115] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A hot-pressed epoxy adhesive composition, characterized in that: The hot-pressed epoxy adhesive composition comprises the following components by weight: 30 to 50 parts of saturated polyester resin, 20 to 40 parts of epoxy resin, 0.1 to 5 parts of epoxy curing agent and 20 to 60 parts of solvent; The saturated polyester resin includes a hydroxyl type saturated polyester resin and a carboxyl type saturated polyester resin.

2. The hot-pressed epoxy adhesive composition according to claim 1, characterized in that: The hydroxyl type saturated polyester resin comprises a hydroxyl type saturated polyester resin A and a hydroxyl type saturated polyester resin B; Preferably, the acid value of the hydroxyl saturated polyester resin A is ≤2 mgKOH / g, the hydroxyl value is 6 to 10 mgKOH / g, and the glass transition temperature is -20 to -10°C; Preferably, the carboxyl type saturated polyester resin has an acid value of 15 to 20 mgKOH / g, a hydroxyl value of ≤5 mgKOH / g, and a glass transition temperature of 20 to 50°C; Preferably, the acid value of the hydroxyl-type saturated polyester resin B is ≤2 mgKOH / g, the hydroxyl value is 6 to 10 mgKOH / g, and the glass transition temperature is 50 to 90° C.; Preferably, the weight proportion of the hydroxyl type saturated polyester resin A is 22 to 26 parts, the weight proportion of the carboxyl type saturated polyester resin is 7 to 9 parts, and the weight proportion of the hydroxyl type saturated polyester resin B is 7 to 9 parts.

3. The hot-pressed epoxy adhesive composition according to claim 1 or 2, characterized in that: The epoxy resin includes epoxy resin A and / or epoxy resin B; Preferably, the epoxy resin A and the epoxy resin B each independently include any one or a combination of at least two of bisphenol A epoxy resin, novolac epoxy resin, CTBN modified epoxy resin, benzaldehyde novolac resin, dimer acid modified epoxy resin or polyurethane modified epoxy resin; Preferably, the epoxy resin A comprises CTBN-modified bisphenol A epoxy resin, the epoxy equivalent of the CTBN-modified bisphenol A epoxy resin is 1000 to 1700 g / eq, and the softening point is ≤100° C.; Preferably, the epoxy resin B comprises liquid bisphenol A epoxy resin, the epoxy equivalent of the liquid bisphenol A epoxy resin is 180 to 200 g / eq, and the viscosity at 25° C. is 10,000 to 18,000 cps.

4. The hot-pressing epoxy adhesive composition according to any one of claims 1 to 3, characterized in that: The epoxy curing agent includes a latent curing agent; Preferably, the latent curing agent includes any one of an organic acid hydrazide curing agent, an aromatic polyamine curing agent, an acid anhydride curing agent or a dicyandiamide curing agent, or a combination of at least two thereof.

5. The hot-pressing epoxy adhesive composition according to any one of claims 1 to 4, characterized in that: The hot-pressed epoxy adhesive composition further comprises 0.5 to 5 parts by weight of an isocyanate curing agent; Preferably, the isocyanate curing agent comprises aromatic polyisocyanate and / or aliphatic polyisocyanate.

6. The hot-pressing epoxy adhesive composition according to any one of claims 1 to 5, characterized in that: The hot-pressed epoxy adhesive composition further comprises 20 to 40 parts by weight of filler; Preferably, the filler comprises an inorganic filler and / or a flame retardant; Preferably, the inorganic filler comprises any one of boron nitride, silicon dioxide, aluminum oxide or superconducting carbon fiber, or a combination of at least two thereof; Preferably, the flame retardant includes any one or a combination of at least two of hypophosphite, diphenyl phosphate, aluminum hydroxide or diethylaluminum hypophosphite, and more preferably hypophosphite; Preferably, the hypophosphite comprises diethylaluminum hypophosphite; Preferably, the D50 particle size of the diethyl aluminum hypophosphite is 3 to 6 μm, and the D100 particle size is 13 to 22 μm; Preferably, the solvent includes any one of butanone, isopropanol, ethyl acetate or toluene, or a combination of at least two thereof.

7. A method for preparing a hot-pressed epoxy adhesive composition according to any one of claims 1 to 6, characterized in that: The preparation method comprises the following steps: mixing saturated polyester resin, epoxy resin, epoxy curing agent and solvent to obtain the hot-pressing epoxy adhesive composition.

8. The preparation method according to claim 7, characterized in that: The mixing also includes mixing with an isocyanate curing agent; Preferably, the mixing further comprises mixing with a filler.

9. An adhesive tape, characterized in that: The adhesive tape comprises an epoxy adhesive layer, and the epoxy adhesive layer is prepared from the hot-pressing epoxy adhesive composition according to any one of claims 1 to 6.

10. The preparation method according to claim 9, characterized in that: The adhesive tape includes a single-sided adhesive tape, a double-sided adhesive tape or a substrate-free adhesive tape.

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