Hot tack adhesive composition, adhesive and article thereof

Abstract

The present application relates to the technical field of adhesive, in particular to a kind of hot tack-reducing adhesive composition, adhesive and its product.The hot tack-reducing adhesive composition includes the following components by weight fraction:100 parts of first copolymer, 60-140 parts of second copolymer, 1-10 parts of first tackifying resin, 1-10 parts of second tackifying resin and 0.05-2 parts of crosslinking agent, wherein the first copolymer is acrylate copolymer, the second copolymer is bonded by selenium-selenium bond between polymerized monomers, the softening point of the first tackifying resin is ≤70 DEG C, and the softening point of the second tackifying resin is >90 DEG C.The hot tack-reducing adhesive composition of the present application has good tack before heating, can quickly reduce tack after medium temperature (70-80 DEG C) heating, and there is no adhesive residue in peeling;At the same time, the adhesive can restore tack at low temperature, the tack-reducing effect is reversible, and the adhesive product can be reused.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of adhesives, in particular to a hot debonding adhesive composition, an adhesive and a product thereof. BACKGROUND

[0002] The hot debonding adhesive is a pressure-sensitive adhesive with adjustable peeling strength. After being heated to a certain temperature, the peeling strength decreases significantly, thereby facilitating the peeling from the adherend. The hot debonding adhesive is widely used in the bonding and fixing of electronic product components such as mobile phones, tablets, computers, battery modules, screen modules and frames. When the electronic products need to be reworked, repaired or inspected, the bonding strength of the bonding part can be reduced by heating, and then the bonding part can be separated.

[0003] The current hot debonding adhesive mainly realizes the hot debonding effect by adding foaming microspheres. The foaming microspheres expand at high temperature, changing the contact area between the adhesive and the adherend, thereby realizing debonding. However, the foaming microspheres are sensitive to the environment, affecting the storage stability of the adhesive. Moreover, the expansion process of the foaming microspheres is irreversible, and the adhesive product cannot be reused. In addition, in order to improve the compatibility of the foaming microspheres and the adhesive, low softening point resins and plasticizers are introduced. However, such additives weaken the cohesive strength of the adhesive, thereby causing residue.

[0004] Chinese patent application CN119193054A discloses a hot debonding pressure-sensitive adhesive. At room temperature, cyclopentadienyl acrylate monomers dimerize into dicyclopentadiene, which polymerizes with acrylate monomers to form acrylate long-chain polymers. Through cross-linking with a curing agent, a three-dimensional network structure is formed, which has high adhesion at room temperature. At high temperature of 170℃, the dicyclopentadiene undergoes depolymerization to generate cyclopentadiene, and the long-chain polymer is broken, resulting in partial destruction of the three-dimensional network structure, increased fluidity, narrowed molecular weight distribution, and reduced peeling strength of the pressure-sensitive adhesive, thereby achieving the effect of hot debonding. However, the debonding temperature of the pressure-sensitive adhesive is too high, which is not suitable for electronic products such as mobile phones and tablets. Therefore, it is of great significance to develop a hot debonding adhesive with low debonding temperature, reusability and no residue.

[0005] In view of the above, the present application is proposed. SUMMARY

[0006] The present application provides a hot debonding adhesive composition, an adhesive and a product thereof. The hot debonding adhesive composition has good adhesion before heating, can quickly debond after medium-temperature (70-80℃) heating, and has no residue after peeling. At the same time, the adhesive can restore adhesion at low temperature, the debonding effect is reversible, and the adhesive product can be reused.

[0007] To achieve the above object, the present application provides a hot-tack adhesive composition, comprising the following components by weight:

[0008] a first copolymer 100 parts

[0009] a second copolymer 60-140 parts

[0010] a first tackifying resin 1-10 parts

[0011] a second tackifying resin 1-10 parts

[0012] a crosslinking agent 0.05-2 parts,

[0013] wherein the first copolymer is an acrylate copolymer, the second copolymer is bonded by selenium-selenium bond between polymerized monomers, the softening point of the first tackifying resin is ≤70℃, and the softening point of the second tackifying resin is >90℃.

[0014] Further, the weight average molecular weight of the acrylate copolymer is 1,500-12,000 g / mol.

[0015] Further, the acrylate copolymer contains 75-95 wt% of (meth)acrylic alkyl ester with alkyl carbon number of 1-14 and 5-25 wt% of polar monomer containing hydroxyl, based on the total weight of monomer components in the acrylate copolymer being 100 wt%.

[0016] Further, the polymerized monomers of the second copolymer are obtained by polyol and selenium lactone ring opening oxidation.

[0017] Further, the selenium lactone includes γ-selenobutyrolactone.

[0018] Further, the polyol is ethylene glycol, and the structure of the polymerized monomers of the second copolymer is shown in the following formula (1):

[0019] Formula (1).

[0020] Further, the polyol is glycerol, and the structure of the polymerized monomers of the second copolymer is shown in the following formula (2):

[0021] Formula (2).

[0022] Further, the first tackifying resin and the second tackifying resin are independently selected from at least one of terpene-based resin, rosin and rosin modified resin, and petroleum resin.

[0023] The present application provides an adhesive comprising the hot-tack adhesive composition provided by the first aspect of the present application.

[0024] The third aspect of the present application provides a heat debonding product, comprising a heat debonding adhesive layer; the heat debonding adhesive layer is prepared from the heat debonding adhesive provided by the second aspect of the present application, or contains the heat debonding adhesive composition according to the first aspect of the present application.

[0025] Compared with the prior art, the present application has the following beneficial effects:

[0026] In the heat debonding adhesive composition of the present application, by introducing the second copolymer bonded by selenium-selenium bond, under the heating condition of 70-80℃, the selenium-selenium bond in the molecular chain is broken and exchanged, the molecular crosslinking network structure is destroyed, the molecular chain is shortened and the flowability is increased, achieving the effect of heat debonding; and the adhesive product has good re-adhesion after heat debonding, and can be reused; by adding an appropriate amount of low softening point first tackifying resin, the heat debonding effect can be effectively improved; the introduction of an appropriate amount of high softening point second tackifying resin can effectively improve the peel strength. DETAILED DESCRIPTION

[0027] The technical solutions of the present application will be described clearly and completely in combination with the specific embodiments below, but those skilled in the art will understand that the following described embodiments are part of the embodiments of the present application, not all the embodiments, and are only used to illustrate the present application, and should not be regarded as limiting the scope of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application. If the specific conditions are not specified in the embodiments, the conventional conditions or the conditions recommended by the manufacturer are used. If the reagents or instruments used are not specified by the manufacturer, they are all conventional products that can be purchased on the market.

[0028] It should be noted that (methyl) acrylic acid in the present application refers to one or both of methacrylic acid and acrylic acid. Similarly, (methyl) alkyl acrylate in the present application refers to one or both of methyl alkyl acrylate and alkyl acrylate.

[0029] The first aspect of the present application provides a heat debonding adhesive composition, comprising the following components in parts by weight:

[0030] 100 parts of the first copolymer

[0031] 60-140 parts of the second copolymer

[0032] 1-10 parts of the first tackifying resin

[0033] 1-10 parts of the second tackifying resin

[0034] 0.05-2 parts of the crosslinking agent,

[0035] The first copolymer is an acrylate copolymer, the second copolymer is bonded by selenium-selenium bond, the softening point of the first tackifying resin is less than or equal to 70 DEG C, and the softening point of the second tackifying resin is greater than 90 DEG C.

[0036] In the heat-tack-reducing adhesive composition of the present application, by introducing the second copolymer bonded by selenium-selenium bond, under the condition of heating at 70-80 DEG C, the selenium-selenium bond in the molecular chain is broken and exchanged, the molecular crosslinking network structure is destroyed, the molecular chain is shortened and the fluidity is increased, thus achieving the effect of heat-tack-reducing; and the adhesive product has good tack after heat-tack-reducing and can be used repeatedly for many times; the appropriate low softening point first tackifying resin can effectively improve the heat-tack-reducing effect; and the introduction of the appropriate high softening point second tackifying resin can effectively improve the peeling force and ensure the bonding effect.

[0037] In the specific embodiment of the present application, the (meth) acrylate alkyl ester accounts for 75-95 wt% of the total weight of the monomer components in the acrylate copolymer, and the polar monomer containing hydroxyl accounts for 5-25 wt%.

[0038] In the specific embodiment of the present application, the (meth) acrylate alkyl ester can be exemplified by (meth) acrylate methyl ester, (meth) acrylate ethyl ester, (meth) acrylate butyl ester, (meth) acrylate-2-ethylhexyl ester, (meth) acrylate dodecyl ester, etc. The (meth) acrylate alkyl ester can be selected from at least one of the above exemplified.

[0039] In the specific embodiment of the present application, the content of the (meth) acrylate alkyl ester accounts for 75-95 wt% of the total weight of the monomer components in the acrylate copolymer, and specifically can be 75 wt%, 80 wt%, 85 wt%, 90 wt%, 95 wt% or any value between the two end values.

[0040] In the specific embodiment of the present application, the polar monomer can be exemplified by (meth) acrylate hydroxyethyl ester, (meth) acrylate hydroxypropyl ester, (meth) acrylate-4-hydroxybutyl ester, etc. The polar monomer can be selected from at least one of the above exemplified.

[0041] In the specific embodiment of the present application, the content of the polar monomer accounts for 5-25 wt% of the total weight of the monomer components in the acrylate copolymer, and specifically can be 5 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt% or any value between the two end values.

[0042] In the specific embodiments of the present application, the acrylic ester copolymer can be prepared by using conventional polymerization methods, such as thermal initiation or free radical initiation. In the initiation of polymerization, a certain amount of initiator is required, and the initiator can be selected from conventional initiators, such as azo initiators and peroxide initiators. Examples of the azo initiators include azobisisobutyronitrile (AIBN), azobisisoheptyl nitrile, and (2,4,6-trimethylbenzoyl)-diphenylphosphine oxide (TPO). Examples of the peroxide initiators include dibenzoyl peroxide (BPO).

[0043] The amount of the initiator is 0.1-1.5 parts by weight, based on 100 parts by weight of the total weight of the monomer components in the acrylic ester copolymer. Specifically, the amount of the initiator can be 0.1 part by weight, 0.5 part by weight, 0.7 part by weight, 1.0 part by weight, 1.5 part by weight, or any value within the range.

[0044] In the specific embodiments of the present application, the polymerization method of the acrylic ester copolymer can be a conventional solvent-type polymerization method. For example, an alkyl (meth)acrylate and a polar monomer are mixed, an appropriate amount of solvent is added, and an initiator is added under a nitrogen atmosphere to perform polymerization. After the reaction, the acrylic ester copolymer is obtained.

[0045] In the specific embodiments of the present application, the polymerization temperature is 60-70°C, and the reaction time is 1-8 hours.

[0046] In the specific embodiments of the present application, a certain amount of chain transfer agent can be added to control the degree of polymerization of the acrylic ester copolymer. The chain transfer agent can be a mercaptan compound, such as dodecanethiol. The amount of the chain transfer agent added is 0.01-1 part by weight, based on 100 parts by weight of the total weight of the monomer components in the acrylic ester copolymer. Specifically, the amount of the chain transfer agent can be 0.01 part by weight, 0.1 part by weight, 0.5 part by weight, 0.7 part by weight, 0.9 part by weight, 1.0 part by weight, or any value within the range.

[0047] In the specific embodiments of the present application, the weight average molecular weight of the acrylic ester copolymer is 1,500-12,000 g / mol. Specifically, the weight average molecular weight can be 1,500 g / mol, 2,000 g / mol, 3,000 g / mol, 5,000 g / mol, 8,000 g / mol, 10,000 g / mol, 12,000 g / mol, or any value within the range. In the present application, the weight average molecular weight of the acrylic ester copolymer is limited to the range, and thus a balance between viscosity reduction and adhesion can be achieved. If the weight average molecular weight of the acrylic ester copolymer is too high, the proportion of selenium-selenium bonds in the adhesive decreases, which is not conducive to thermal viscosity reduction. Conversely, the adhesion of the adhesive decreases.

[0048] In the detailed description of the present application, the solvent can be a conventional non-alcohol solvent, such as at least one of toluene, xylene, ethyl acetate, and acetone.

[0049] In the detailed description of the present application, the polymerized monomers of the second copolymer are obtained by ring-opening oxidation of a polyol and selenolactone.

[0050] In the detailed description of the present application, the selenolactone includes γ-selenobutyrolactone.

[0051] In the detailed description of the present application, the polyol is ethylene glycol, and the polymerized monomers of the second copolymer have the following structure shown in formula (1):

[0052] Formula (1).

[0053] In the detailed description of the present application, the polyol is glycerol, and the polymerized monomers of the second copolymer have the following structure shown in formula (2):

[0054] Formula (2).

[0055] In the detailed description of the present application, the present application provides an optional preparation method of the second copolymer, in which γ-selenobutyrolactone, a polyol, a catalyst, and a solvent are uniformly mixed, heated for reaction, and then the solvent is dried after the reaction is completed, so as to obtain the second copolymer.

[0056] In the detailed description of the present application, the heating temperature is 60-80°C, and the reaction time is 100-140 h.

[0057] In the detailed description of the present application, the catalyst can be an amidine compound with a double heterocyclic structure, such as 1,8-diazabicycloundec-7-ene (DBU).

[0058] In the detailed description of the present application, the solvent can be tetrahydrofuran (THF).

[0059] In the detailed description of the present application, the amount of the second copolymer is 60-140 parts by weight, specifically 60 parts, 70 parts, 80 parts, 90 parts, 100 parts, 110 parts, 120 parts, 130 parts, 140 parts, or any value between any two of the above values, compared to 100 parts by weight of the acrylate copolymer. If the amount of the second copolymer is too low, the effect of reducing viscosity and the improvement of viscosity after viscosity reduction are not obvious; if the amount is too high, the adhesive will have insufficient peel strength.

[0060] In the specific embodiments of the present application, the softening point of the first tackifying resin is not higher than 70℃. The introduction of the low softening point first tackifying resin can improve the compatibility between the first tackifying resin and other components of the adhesive, because the first tackifying resin is in a softened fluid state under the operating conditions of medium temperature (70-80℃) heat debonding.

[0061] In the specific embodiments of the present application, the first tackifying resin comprises at least one of terpene-based resin, rosin and rosin modified resin, and petroleum resin. The low softening point first tackifying resin has good compatibility with the remaining components of the adhesive, and the low softening point first tackifying resin softens or even flows after being heated, which promotes the softening and phase transition of the entire adhesive layer, and further promotes the heat debonding effect.

[0062] The first tackifying resin in the present application can use commercially available products, such as C5 petroleum resin Wingtack 87 produced by Cray Valley American Limited Liability Company. ® 10, softening point 10℃; rosin modified terpene resin R-401 (softening point 20-30℃), terpene resin T-301 (softening point 22-32℃) and rosin resin 501 (softening point 20-30℃) provided by Shenzhen Yunlin Chemical Co., Ltd.; C5 petroleum resin Quintone B170 produced by Japan Zeon Corporation, softening point 70℃; terpene resin Dercolyte LTG produced by France DRT Company, softening point 20℃. ® B170, softening point 70℃; terpene resin Dercolyte LTG produced by France DRT Company, softening point 20℃.

[0063] In the specific embodiments of the present application, the amount of the first tackifying resin is 1-10 parts by weight, compared to 100 parts by weight of the acrylate copolymer, and specifically can be 1 part, 2 parts, 3 parts, 5 parts, 7 parts, 7.5 parts, 10 parts, or any value between any two of the above values. If the amount of the first tackifying resin is too low in the present application, the heat debonding effect will be relatively poor, for example, the peel strength after heating is high; if the amount of the first tackifying resin is too high, the cohesive force of the adhesive layer will be poor.

[0064] In the specific embodiments of the present application, the softening point of the second tackifying resin is higher than 90℃. The addition of the second tackifying resin with high softening point in the present application will not soften under the operating conditions of medium temperature (70-80℃) heat debonding, and the second tackifying resin with high softening point will not soften and flow under heating conditions, which can enhance the entanglement and physical crosslinking between the molecular chains of the adhesive, improve the high temperature cohesive force and creep resistance, and thus facilitate the peel without residue.

[0065] In the detailed description of the present application, the second tackifying resin comprises at least one of terpene-based resin, rosin and rosin modified resin, and petroleum resin. The second tackifying resin used in the present application can be a commercially available product, such as terpene phenol resin 803-L produced by Arakawa Chemical Industries, Ltd., Japan, with a softening point of 145-160℃.

[0066] In the detailed description of the present application, the second tackifying resin is used in an amount of 1-10 parts by weight, specifically 1 part, 3 parts, 5 parts, 8 parts, 10 parts, or any value between any two of the above-mentioned values, relative to 100 parts by weight of the acrylate copolymer. If the amount of the second tackifying resin is too low, the adhesive will have a low tackiness. If the amount of the second tackifying resin is too high, the residual tackiness after heat-tack-reducing will be high, and the heat-tack-reducing effect will not be obvious.

[0067] In the detailed description of the present application, the crosslinking agent comprises isocyanate-based crosslinking agent. Further, the isocyanate-based crosslinking agent comprises at least one of aromatic isocyanate, alicyclic isocyanate, and aliphatic isocyanate.

[0068] For example, the aromatic isocyanate can be toluene diisocyanate (TDI), 4,4'-diphenylmethane diisocyanate, p-phenylene diisocyanate, etc.; the alicyclic isocyanate can be isophorone diisocyanate; and the aliphatic isocyanate can be hexamethylene diisocyanate (HDI), HDI trimer, trimethylolpropane triisocyanate, etc.

[0069] In the detailed description of the present application, the crosslinking agent is used in an amount of 0.05-2 parts by weight, specifically 0.05 parts, 0.1 parts, 0.2 parts, 0.5 parts, 0.8 parts, 1 part, 1.2 parts, 1.5 parts, 1.8 parts, 2 parts, or any value between any two of the above-mentioned values, relative to 100 parts by weight of the acrylate copolymer. The amount of the crosslinking agent within the above-mentioned range is beneficial to maintaining the balance between the peel strength, cohesive strength, and heat-tack-reducing effect of the adhesive. If the amount of the crosslinking agent is too low, the cohesion will be poor, and the adhesive strength will be insufficient. If the amount of the crosslinking agent is too high, the cohesive strength will be too large, which will affect the breaking and recombination of molecular chains during the heating process, and thus the heat-tack-reducing effect will be poor.

[0070] The second aspect of the present application further provides an adhesive comprising the heat-tack-reducing adhesive composition according to the first aspect of the present application.

[0071] In the present application, the preparation method of the adhesive is not limited, and the commonly used preparation method of the adhesive can be used. The present application provides an optional preparation method of the adhesive, which comprises the following steps: mixing the first copolymer and the second copolymer, adding the first tackifying resin, stirring uniformly, adding the crosslinking agent for crosslinking reaction, then adding the second tackifying resin, stirring uniformly, standing and defoaming, and then obtaining the adhesive to be coated.

[0072] In the specific embodiment of the present application, a certain amount of solvent can be added during the preparation of the adhesive. Optionally, the solvent can be added to adjust the solid content of the adhesive to 15% to 45% to ensure that the adhesive has appropriate leveling property.

[0073] In the specific embodiment of the present application, the solvent can be at least one of conventional non-alcohol organic solvents, such as ethyl acetate (EA), toluene, xylene, and acetone.

[0074] It can be understood that, in order to facilitate production, transportation and sales, the adhesive of the present application is only limited in component composition but not in the form of existence of the components, that is, the components can be mixed with each other or can be stored independently. The mixing or independent storage mode can be selected according to the actual use occasion.

[0075] The adhesive of the present application can also add a certain amount of other additives according to the requirements, such as defoaming agent, antistatic agent, etc.

[0076] The third aspect of the present application provides a heat-reduced adhesive product, which comprises a heat-reduced adhesive layer; the heat-reduced adhesive layer is prepared from the adhesive provided by the second aspect of the present application, or contains the heat-reduced adhesive composition provided by the first aspect of the present application.

[0077] In the specific embodiment of the present application, the heat-reduced adhesive product can include single-sided adhesive tape, double-sided adhesive tape, etc. The specific type of adhesive tape can be adjusted according to the actual requirements.

[0078] In the specific embodiment of the present application, the double-sided adhesive tape comprises a substrate layer and a heat-reduced adhesive layer arranged on both sides of the substrate layer.

[0079] In the specific embodiment of the present application, the thickness of the heat-reduced adhesive layer is 10 to 300 μm, and specifically can be 10 μm, 30 μm, 50 μm, 80 μm, 100 μm, 150 μm, 200 μm, 250 μm, 300 μm or any value between any two of the above values.

[0080] In the specific embodiment of the present application, the substrate layer comprises at least one of polyethylene (PE) foam, polyurethane (PU) foam, polypropylene (PP) foam and polyvinyl chloride (PVC) foam.

[0081] In the detailed description of the present application, the thickness of the substrate layer is 30-400 μm, specifically 30 μm, 60 μm, 100 μm, 150 μm, 200 μm, 300 μm, 400 μm or a value between any two of the above values.

[0082] The present application also provides a preparation method of the heat debonding product, comprising the following steps: coating the adhesive to be coated on the surface of the substrate, drying to obtain a heat debonding adhesive layer, and aging to obtain the heat debonding product.

[0083] In the detailed description of the present application, the drying temperature is 100-120℃, and the drying time is 3-5 min.

[0084] In the detailed description of the present application, the aging temperature is 40-60℃, and the aging time is 2-4 d.

[0085] In the detailed description of the present application, the substrate includes a release film or the above-mentioned foam.

[0086] In the detailed description of the present application, in order to facilitate winding, transportation and avoid dirt on the surface of the product, a layer of release film can be coated on the surface of the heat debonding adhesive layer. The release film includes but is not limited to PET silicone release film. The thickness of the release film can be freely selected according to actual needs, and is not particularly limited, for example, it can be set to 30-50 μm, specifically 30 μm, 36 μm, 40 μm, 45 μm, 50 μm or a value between any two of the above values.

[0087] In actual operation, the coating method is not limited, and roll coating, blade coating or dip coating can be used. In actual operation, a coater can be used for coating.

[0088] In the detailed description of the present application, when the heat debonding product is attached to the surface of the attached object, and the adhesion needs to be reduced, heating treatment is used to reduce the adhesion; wherein the heating treatment temperature is 70-80℃, and the heating treatment time is 10-20 min.

[0089] In the detailed description of the present application, when the heat debonding product is reduced in adhesion by heating treatment, and the adhesion needs to be restored, the heat debonding product is placed under normal temperature conditions for a certain period of time to restore the adhesion, for example, placed for 2 h. The normal temperature referred to in the present application refers to 23±1℃, 50±5% RH.

[0090] The following specific examples are used to further illustrate the objects and advantages of the present application, but these examples should not be regarded as limiting the present application. In the following examples, 1 g represents 1 part by weight.

[0091] The weight average molecular weight of the acrylate copolymer in the following examples was measured by gel permeation chromatography (GPC). The softening point of the tackifying resin in the following examples was provided by the manufacturer and can be measured according to the ring and ball method.

[0092] Example 1

[0093] Preparation of the acrylate copolymer: 85 g of ethyl acrylate, 15 g of hydroxyethyl methacrylate and 50 g of toluene were added to a reaction kettle, nitrogen was introduced, stirred and heated to 65°C, 1.3 g of AIBN was dissolved in 13 g of toluene solvent and slowly added to the reaction kettle, stirred for 10 min, 0.13 g of dodecanethiol was added and stirred for 2 h, after removing the solvent, an acrylate copolymer with a weight average molecular weight of 3,500 g / mol was obtained.

[0094] Preparation of the second copolymer: γ-selenobutyrolactone 600 g (4 mol), ethylene glycol 124 g (2 mol), DBU 30.4 g (0.2 mol) and 2 L of THF were placed in a reaction kettle, refluxed at 70°C for 120 h; the mixed solution was precipitated in n-hexane, stood for 2 h, the upper layer solution was removed, and the lower layer yellow oily viscous liquid was precipitated three times to remove unreacted substances, and the last lower precipitate was vacuum dried for 24 h to obtain the second copolymer.

[0095] The prepared acrylate copolymer 100 g, the second copolymer 100 g and 500 g of ethyl acetate were mixed uniformly, then the first tackifying resin terpene resin Dercolyte LTG (DRT, softening point 20°C) 5 g and the crosslinking agent TDI 0.5 g were added, reacted for 1 h, then the second tackifying resin terpene phenolic resin 803-L (Arakawa Chemical Industries, softening point 145-160°C) 5 g and a certain amount of ethyl acetate were added, mixed uniformly, defoamed and stood to obtain an adhesive with a solid content of 25%.

[0096] The adhesive was coated on the surface of a 50 μm thick PET release film, placed in a 110°C oven for 2 min to form a 30 μm thick adhesive layer, and the adhesive layer was attached to the other side of the 50 μm thick foam; the adhesive was coated on the surface of another 36 μm thick PET release film, placed in a 110°C oven for 2 min to form a 30 μm thick adhesive layer, and the adhesive layer was attached to the other side of the foam, cured in a 50°C oven for 3 d, and cooled at room temperature for 3 h to obtain a hot reduced adhesive tape.

[0097] Example 2

[0098] This example was carried out as in Example 1, with the only difference being the amount of some components in the adhesive, which was prepared and had the same solid content as in Example 1, with the specific differences being as follows:

[0099] Second copolymer 60 g, terpene resin Dercolyte LTG 1 g, crosslinking agent TDI 0.05 g, terpene phenol aldehyde resin 803-L 1 g.

[0100] Example 3

[0101] This example was carried out as in Example 1, with the only difference being the amount of some components in the adhesive, which was prepared and had the same solid content as in Example 1, with the specific differences being as follows:

[0102] Second copolymer 140 g, terpene resin Dercolyte LTG 10 g, crosslinking agent TDI 2 g, terpene phenol aldehyde resin 803-L 10 g.

[0103] Example 4

[0104] This example was carried out as in Example 1, with the only difference being that 128 g of glycerol (1.4 mol) was used instead of ethylene glycol in the preparation of the second copolymer in the adhesive, and the adhesive was prepared and had the same solid content as in Example 1.

[0105] Example 5 group

[0106] This example group was carried out as in Example 1, with the only difference being the amount of some components of the acrylate copolymer in the adhesive, which was prepared and had the same solid content as in Example 1, with the specific differences being as follows:

[0107] Example 5a: the amount of initiator was 1.5 g, and dodecanethiol was 0.15 g, and the weight average molecular weight of the acrylate copolymer obtained was 2,000 g / mol;

[0108] Example 5b: the amount of initiator was 0.7 g, and dodecanethiol was 0.08 g, and the weight average molecular weight of the acrylate copolymer obtained was 12,000 g / mol;

[0109] Example 5c: the amount of initiator was 2.3 g, and dodecanethiol was 0.2 g, and the weight average molecular weight of the acrylate copolymer obtained was 1,000 g / mol;

[0110] Example 5d: the amount of initiator was 0.6 g, and dodecanethiol was 0.05 g, and the weight average molecular weight of the acrylate copolymer obtained was 14,000 g / mol.

[0111] Comparative Example 1 group

[0112] The comparative example group was prepared according to example 1, with the only difference being the amount of second copolymer in the adhesive, the preparation method and the solid content were the same as example 1, the specific difference is shown as follows:

[0113] Comparative example 1a: without second copolymer;

[0114] Comparative example 1b: the amount of second copolymer is 50 g;

[0115] Comparative example 1c: the amount of second copolymer is 150 g.

[0116] Comparative example 2

[0117] The comparative example group was prepared according to example 1, with the only difference being that the adhesive did not contain an acrylate copolymer, the preparation method and the solid content were the same as example 1.

[0118] Comparative example 3 group

[0119] The comparative example group was prepared according to example 1, with the only difference being the amount of first tackifying resin in the adhesive, the preparation method and the solid content were the same as example 1, the specific difference is shown as follows:

[0120] Comparative example 3a: without terpene resin Dercolyte LTG;

[0121] Comparative example 3b: the amount of terpene resin Dercolyte LTG is 12 g;

[0122] Comparative example 3c: the amount of terpene resin Dercolyte LTG is 0.5 g.

[0123] Comparative example 4 group

[0124] The comparative example group was prepared according to example 1, with the only difference being the amount of second tackifying resin in the adhesive, the preparation method and the solid content were the same as example 1, the specific difference is shown as follows:

[0125] Comparative example 4a: without terpene phenolic resin 803-L;

[0126] Comparative example 4b: the amount of terpene phenolic resin 803-L is 12 g;

[0127] Comparative example 4c: the amount of terpene phenolic resin 803-L is 0.5 g.

[0128] Comparative example 5 group

[0129] The comparative example group was prepared according to example 1, with the only difference being the type of first or second tackifying resin in the adhesive, the preparation method and the solid content were the same as example 1, the specific difference is shown as follows:

[0130] Comparative Example 5a: The first tackifying resin was replaced with an equal weight of rosin resin GB-75 (manufacturer: Arakawa Chemical Industries, Ltd., Japan, softening point 70-80°C);

[0131] Comparative Example 5b: The second tackifying resin was replaced with an equal weight of rosin resin A-75 (manufacturer: Arakawa Chemical Industries, Ltd., Japan, softening point 70-80°C).

[0132] Test Example

[0133] The adhesive tapes prepared in each of the above examples and comparative examples were subjected to the following tests, and the test results are shown in Table 1.

[0134] 1. 180° peeling force: tested according to the national standard GB / T 2792-2014 "Adhesive tape peeling strength test method", taking 100 mm x 25 mm adhesive tape sample, after tearing off one side release film, pasting with 25 μm PET film, tearing off the other side release film, pasting with SUS304 steel plate, rolling with 1 kg stainless steel roller at a speed of 600 mm / min for 2 rounds, obtaining the test sample, testing the 180° peeling force of the test sample under different conditions, peeling speed 300 mm / min, expressed in gf / mm;

[0135] (1) The test sample was tested after being placed at room temperature (RT, 23±1°C, 50±5%RH) for 30 min, and the peeling force requirement was different for different application scenarios. Generally, the peeling force was not less than 3,200 gf / mm;

[0136] (2) The test sample was placed in a 75°C oven for 15 min after being placed at room temperature for 30 min, and the adhesion-reducing peeling force after the first heating was tested. Generally, if the peeling force was not more than 400 gf / mm, it was easy to peel off;

[0137] (3) The test sample after peeling in step (2) above was pasted with the steel plate according to the same operation, and the peeling force after the first tack was tested after being placed at room temperature for 2 h;

[0138] (4) The test sample after peeling in step (2) above was pasted with the steel plate according to the same operation, and the adhesion-reducing peeling force after the second heating was tested after being placed at room temperature for 2 h;

[0139] (5) The test sample after peeling in step (4) above was pasted with the steel plate according to the same operation, and the peeling force after the second tack was tested after being placed at room temperature for 2 h;

[0140] (6) The test sample peeled off in step (4) above is attached to the steel plate according to the same operation, and is placed at room temperature for 2 h, and then the third time heating adhesion reduction peel strength thereof is tested according to operation (2).

[0141] 2. Adhesion retention test: The test is carried out according to the national standard GB / T 4851-2014 "Test method for adhesion retention of adhesive tape", a 75 mm x 25 mm adhesive tape sample is taken, after the release film on one side is torn off, it is attached to a 25 μm PET film, after the release film on the other side is torn off, it is attached to a SUS304 steel plate, the attachment area is 25 mm x 25 mm; a 2 kg rubber roller is rolled back and forth for 2 times at a speed of 600 mm / min to obtain a test sample;

[0142] The test sample is placed vertically on the test frame for 30 min at room temperature, a 1 kg weight is hung below, and the sliding distance of the adhesive tape after 24 h is recorded;

[0143] The test sample is placed vertically on the test frame for 30 min at room temperature, a 1 kg weight is hung below at 80℃, and the falling time of the adhesive tape is recorded.

[0144] Table 1. Performance test results of different examples and comparative examples

[0145]

[0146] It can be known from the above test results that, in the hot adhesion reduction adhesive composition of the application, the second polymer containing selenium-selenium bond is introduced, under the heating condition of 70-80℃, the selenium-selenium bond in the molecular chain is broken and exchanged, the molecular crosslinking network structure is destroyed, the molecular chain is shortened and the fluidity is increased, the hot adhesion reduction effect is achieved; and after hot adhesion reduction, it has good adhesion retention and can be used repeatedly for many times; the addition of an appropriate amount of low softening point first tackifying resin can effectively improve the hot adhesion reduction effect; the introduction of an appropriate amount of acrylic ester copolymer and high softening point second tackifying resin can effectively improve the adhesion of the adhesive.

[0147] It can be known from the test results of example 5 group that, by limiting the weight average molecular weight of the acrylic ester copolymer within a certain range, an adhesive with balanced hot adhesion reduction effect and adhesion retention can be obtained; if the weight average molecular weight of the acrylic ester copolymer is too high, the degree of molecular chain entanglement will increase, which will lead to low peel strength before hot adhesion reduction and high peel strength after hot adhesion reduction; if the weight average molecular weight of the acrylic ester copolymer is too low, the adhesion retention of the adhesive will decrease, which is not conducive to attachment.

[0148] The test results of the comparative example 1 show that if the second copolymer is not added, the high temperature peeling force is still high and the hot tack effect is not good; if the amount of the second copolymer is too low, the high temperature peeling force and the high temperature holding force are still high and the hot tack effect is poor; if the amount of the second copolymer is too high, the room temperature peeling force is significantly reduced and the bonding effect is affected.

[0149] The test results of the comparative example 2 show that if the acrylate copolymer is not added, the room temperature peeling force is significantly reduced.

[0150] The test results of the comparative example 3 show that if the first tackifying resin with low softening point is not added or the amount of the first tackifying resin with low softening point is low, the high temperature peeling force is still high and the peeling is not good; if the amount of the first tackifying resin with low softening point is too high, the room temperature holding force is poor.

[0151] The test results of the comparative example 4 show that if the second tackifying resin with high softening point is not added or the amount of the second tackifying resin with high softening point is low, the room temperature peeling force is reduced; if the amount of the second tackifying resin with high softening point is too high, the high temperature peeling force and the high temperature holding force are high and the hot tack effect is poor.

[0152] The test results of the comparative example 5 show that if the softening point of the first tackifying resin is high, the peeling force after heating is high and the hot tack is not good; if the softening point of the second tackifying resin is low, the room temperature holding force is reduced.

[0153] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A heat-debondable adhesive composition, characterized by, comprises the following components by weight parts: 100 parts of a first copolymer 60-140 parts of a second copolymer 1-10 parts of a first tackifying resin 1-10 parts of a second tackifying resin 0.05-2 parts of a crosslinking agent, wherein the first copolymer is an acrylate copolymer, the second copolymer is bonded by selenium-selenium bond between polymerized monomers, the first tackifying resin has a softening point ≤ 70℃, and the second tackifying resin has a softening point > 90℃.

2. The heat-debondable adhesive composition according to claim 1, characterized in that, The acrylate copolymer has a weight average molecular weight of 1,500-12,000 g / mol.

3. The heat-debondable adhesive composition according to claim 1 or 2, characterized in that, The acrylate copolymer contains 75-95 wt% of (meth)acrylic alkyl ester with alkyl carbon number of 1-14 and 5-25 wt% of polar monomer containing hydroxyl group, based on 100 wt% of total weight of monomer components in the acrylate copolymer.

4. The heat-debondable adhesive composition according to claim 1, wherein The polymerized monomers of the second copolymer are obtained by polyol and selenium lactone ring opening oxidation.

5. The heat-debondable adhesive composition according to claim 4, wherein The selenium lactone comprises γ-selenobutyrolactone.

6. The heat-debondable adhesive composition according to claim 5, wherein The polyol is ethylene glycol, and the structure of the polymerized monomers of the second copolymer is shown in the following formula (1): Formula (1).

7. The heat-debondable adhesive composition according to claim 5, wherein The polyol is glycerol, and the structure of the polymerized monomers of the second copolymer is shown in the following formula (2): Formula (2).

8. The heat-debondable adhesive composition according to claim 1, wherein The first and second tackifying resins are independently selected from at least one of terpene-based resins, rosin and rosin modified resins, and petroleum resins.

9. An adhesive comprising the hot-debondable adhesive composition according to any one of claims 1-8.

10. A heat de-bonded article, characterized by, comprises a hot-debondable adhesive layer; the hot-debondable adhesive layer is prepared from the adhesive according to claim 9, or contains the hot-debondable adhesive composition according to any one of claims 1-8.

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