Thermal visbreaking adhesive composition, adhesive and product thereof

Abstract

The invention relates to the technical field of adhesives, in particular to a thermal visbreaking adhesive composition, an adhesive and a product thereof. The thermal visbreaking adhesive composition comprises the following components in parts by weight: 100 parts of a first copolymer, 60-140 parts of a second copolymer, 1-10 parts of first tackifying resin, 1-10 parts of second tackifying resin and 0.05-2 parts of a cross-linking agent, the first copolymer is an acrylate copolymer, polymeric monomers of the second copolymer are bonded through selenium-selenium bonds, and the cross-linking agent is a cross-linking agent. 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. The thermal visbreaking adhesive composition disclosed by the invention has good viscosity before being heated, can be quickly visbroken after being heated at a medium temperature (70-80 DEG C), and has no adhesive residue after being peeled off; meanwhile, the viscosity of the adhesive can be recovered at low temperature, the viscosity reducing effect is reversible, and the adhesive product can be repeatedly used.

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 heat-reducible adhesive composition, comprising the following components in parts by weight: the first copolymer 100 parts the second copolymer 60-140 parts the first tackifying resin 1-10 parts the second tackifying resin 1-10 parts the crosslinking agent 0.05-2 parts, 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℃.

[0008] Further, the weight average molecular weight of the acrylate copolymer is 1,500-12,000 g / mol.

[0009] 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 as 100 wt%.

[0010] Further, the polymerized monomers of the second copolymer are obtained by polyol and selenium lactone ring opening oxidation.

[0011] Further, the selenium lactone includes γ-selenobutyrolactone.

[0012] Further, the polyol is ethylene glycol, and the polymerized monomer structure of the second copolymer is shown in the following formula (1): Formula (1).

[0013] Further, the polyol is glycerol, and the polymerized monomer structure of the second copolymer is shown in the following formula (2): Formula (2).

[0014] 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.

[0015] The present application provides an adhesive, comprising the heat-reducible adhesive composition provided in the first aspect of the present application.

[0016] The present application provides a heat-reducible product, comprising a heat-reducible adhesive layer; the heat-reducible adhesive layer is prepared from the heat-reducible adhesive provided in the second aspect of the present application, or contains the heat-reducible adhesive composition provided in the first aspect of the present application.

[0017] Compared with the prior art, the application has the following beneficial effects: In the heat-reducing adhesive composition of the 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 fluidity is increased, the heat-reducing effect is achieved; and the adhesive product has good tackiness after heat-reducing and can be reused; by adding the appropriate amount of the first tackifying resin with low softening point, the heat-reducing effect can be effectively improved; by introducing the appropriate amount of the second tackifying resin with high softening point, the peeling force can be effectively improved. DETAILED DESCRIPTION

[0018] The technical solutions of the 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 application, not all the embodiments, and are only used to illustrate the application, and should not be regarded as limiting the scope of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the application. The specific conditions are not specified in the embodiments, and the conventional conditions or the conditions recommended by the manufacturer are used. The reagents or instruments used are not specified by the manufacturer, and are conventional products that can be purchased on the market.

[0019] It should be noted that the (meth)acrylic acid in the application refers to one or both of methacrylic acid and acrylic acid. Similarly, the (meth)acrylic alkyl ester in the application refers to one or both of methacrylic alkyl ester and acrylic alkyl ester.

[0020] The first aspect of the application provides a heat-reducing adhesive composition, which comprises the following components in parts by weight: 100 parts of the first copolymer 60-140 parts of the second copolymer 1-10 parts of the first tackifying resin 1-10 parts of the second tackifying resin 0.05-2 parts of the crosslinking agent, The first copolymer is an acrylic ester copolymer, the second copolymer is bonded by selenium-selenium bond between the polymerized monomers, the softening point of the first tackifying resin is ≤70℃, and the softening point of the second tackifying resin is >90℃.

[0021] 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 fluidity is increased, the heat debonding effect is achieved; and the adhesive product has good re-adhesion after heat debonding, and can be used repeatedly for many times; the appropriate low softening point first tackifying resin can effectively improve the heat debonding effect; the introduction of the appropriate high softening point second tackifying resin can effectively improve the peeling force and ensure the bonding effect.

[0022] In the specific embodiment of the present application, the content of the (meth)alkyl acrylate is 75-95 wt% based on the total weight of the monomer components in the acrylate copolymer being 100 wt%, and the content of the polar monomer is 5-25 wt%.

[0023] In the specific embodiment of the present application, the (meth)alkyl acrylate can be exemplified by (meth)acrylic acid methyl ester, (meth)acrylic acid ethyl ester, (meth)acrylic acid butyl ester, (meth)acrylic acid-2-ethylhexyl ester, (meth)acrylic acid dodecyl ester, etc. The (meth)alkyl acrylate can be selected from at least one of the above exemplified.

[0024] In the specific embodiment of the present application, the content of the (meth)alkyl acrylate is 75-95 wt% based on the total weight of the monomer components in the acrylate copolymer being 100 wt%, and the content of the polar monomer is 5-25 wt%.

[0025] In the specific embodiment of the present application, the polar monomer can be exemplified by (meth)acrylic acid hydroxyethyl ester, (meth)acrylic acid hydroxypropyl ester, (meth)acrylic acid-4-hydroxybutyl ester, etc. The polar monomer can be selected from at least one of the above exemplified.

[0026] In the specific embodiment of the present application, the content of the polar monomer is 5-25 wt% based on the total weight of the monomer components in the acrylate copolymer being 100 wt%, and the content of the polar monomer is 5-25 wt%.

[0027] 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).

[0028] 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.

[0029] 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.

[0030] In the specific embodiments of the present application, the polymerization temperature is 60-70°C, and the reaction time is 1-8 hours.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] In the detailed description of the present application, the selenolactone includes γ-selenobutyrolactone.

[0036] 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): Formula (1).

[0037] 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): Formula (2).

[0038] 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.

[0039] In the detailed description of the present application, the heating temperature is 60-80°C, and the reaction time is 100-140 h.

[0040] 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).

[0041] In the detailed description of the present application, the solvent can be tetrahydrofuran (THF).

[0042] 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.

[0043] In the specific embodiment 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.

[0044] In the specific embodiment 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 in 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.

[0045] 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, 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℃), and terpene resin Dercolyte LTG produced by France DRT Company (softening point 20℃). ® 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℃).

[0046] In the specific embodiment 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 will be high; if the amount of the first tackifying resin is too high, the cohesive force of the adhesive layer will be poor.

[0047] In the specific embodiment 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 facilitate the peeling without adhesive residue.

[0048] 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℃.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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, affecting the breaking and recombination of molecular chains during heating, and leading to poor heat-tack-reducing effect.

[0053] The second aspect of the present application also provides an adhesive comprising the heat-tack-reducing adhesive composition according to the first aspect of the present application.

[0054] In this invention, there are no restrictions on the preparation method of the adhesive; commonly used adhesive preparation methods can be used. This invention provides an optional adhesive preparation method, comprising the following steps: mixing a first copolymer and a second copolymer, adding a first tackifying resin, stirring until homogeneous, then adding a crosslinking agent to carry out a crosslinking reaction, then adding a second tackifying resin, stirring until homogeneous, and allowing to stand to defoam, thereby obtaining the adhesive to be coated.

[0055] In a specific embodiment of the present invention, a certain amount of solvent may be added during the preparation of the adhesive. Optionally, the solvent may be added to adjust the solid content of the adhesive to 15% to 45% to ensure that the adhesive has suitable leveling properties.

[0056] In a specific embodiment of the present invention, the solvent may be a conventional non-alcoholic organic solvent, such as at least one of ethyl acetate (EA), toluene, xylene, and acetone.

[0057] It is understood that, for the convenience of production, transportation, and sales, the adhesive of the present invention only limits the composition of the components and not the form in which the components exist; that is, the components can be mixed together or stored separately. The mixed or separate storage method can be selected according to the actual use.

[0058] Other additives, such as defoamers and antistatic agents, can also be added to the adhesive of the present invention as needed.

[0059] A third aspect of the present invention provides a heat-resistant adhesive article, comprising a heat-resistant adhesive layer; said heat-resistant adhesive layer is made from the adhesive provided in the second aspect of the present invention, or contains the heat-resistant adhesive composition described in the first aspect of the present invention.

[0060] In specific embodiments of the present invention, the heat-resistant adhesive product may include single-sided tape, double-sided tape, etc. The specific type of tape can be adjusted according to actual needs.

[0061] In a specific embodiment of the present invention, the double-sided tape includes a substrate layer and a heat-resistant adhesive layer disposed on both sides of the substrate layer.

[0062] In a specific embodiment of the present invention, the thickness of the heat-resistant adhesive layer is 10 to 300 μm, specifically 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 these values.

[0063] In a specific embodiment of the present invention, the substrate layer includes at least one of polyethylene (PE) foam, polyurethane (PU) foam, polypropylene (PP) foam, and polyvinyl chloride (PVC) foam.

[0064] In a specific embodiment of the present invention, the thickness of the substrate layer is 30 to 400 μm, specifically 30 μm, 60 μm, 100 μm, 150 μm, 200 μm, 300 μm, 400 μm or any value between the two extremes therein.

[0065] The present invention also provides an optional preparation method for the above-mentioned heat-resistant adhesive product, comprising the following steps: applying the adhesive to be coated onto the surface of a substrate, drying it to obtain a heat-resistant adhesive layer, and curing it to obtain the heat-resistant adhesive product.

[0066] In a specific embodiment of the present invention, the drying temperature is 100-120°C and the drying time is 3-5 min.

[0067] In a specific embodiment of the present invention, the curing temperature is 40–60°C and the curing time is 2–4 days.

[0068] In a specific embodiment of the present invention, the substrate includes a release film or one of the foams listed above.

[0069] In a specific embodiment of the present invention, to facilitate winding and transportation and to avoid surface contamination of the product, a release film can be applied to the surface of the heat-resistant 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 any value between these two extremes.

[0070] In practice, the coating method is not limited in the preparation of heat-resistant and non-stick products; roller coating, blade coating, or dip coating can be used. In practice, a coater can also be used.

[0071] In a specific embodiment of the present invention, when the heat-resistant adhesive product is bonded to the surface of the object to be bonded, and when it is necessary to reduce the adhesion, the adhesion is reduced by heat treatment; wherein, the temperature of the heat treatment is 70-80°C and the time of the heat treatment is 10-20 min.

[0072] In a specific embodiment of the present invention, when a heat-reduced tack product needs to regain its tack after being reduced in tack through heat treatment, it can be placed at room temperature for a certain period of time to restore its tackiness, for example, 2 hours. Room temperature as referred to in this invention means 23±1℃ and 50±5%RH.

[0073] The following specific embodiments further illustrate the purpose and advantages of the present invention, but these embodiments should not be regarded as limitations of the present invention. In the following embodiments, 1 g represents 1 part by weight.

[0074] The weight-average molecular weight of the acrylate copolymers in the following examples was measured by gel permeation chromatography (GPC). The softening point of the tackifying resins in the following examples was provided by the manufacturer and can be measured using the ring and ball method.

[0075] Example 1 Preparation of acrylate copolymer: 85 g of ethyl acrylate, 15 g of hydroxyethyl methacrylate and 50 g of toluene were added to a reaction vessel, nitrogen gas was introduced, the mixture was stirred and heated to 65 °C, 1.3 g of AIBN was dissolved in 13 g of toluene solvent and slowly added dropwise to the reaction vessel, the mixture was stirred and reacted for 10 min, and then 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.

[0076] Preparation of the second copolymer: 600 g (4 mol) of γ-selenobutyrolactone, 124 g (2 mol) of ethylene glycol, 0.4 g (0.2 mol) of DBU3 and 2 L of THF were placed in a reaction vessel and refluxed at 70 °C for 120 h; the mixed solution was precipitated in n-hexane, allowed to stand for 2 h, the upper layer of solution was removed, and the lower layer of yellow oily viscous liquid was precipitated three times to remove unreacted substances. The final lower precipitate was dried under vacuum for 24 h to obtain the second copolymer.

[0077] 100 g of the prepared acrylate copolymer, 100 g of the second copolymer, and 500 g of ethyl acetate were mixed evenly. Then, 5 g of the first tackifying resin, terpene resin Dercolyte LTG (DRT, France, softening point 20℃), and 0.5 g of crosslinking agent TDI were added. The mixture was reacted for 1 h. Then, 5 g of the second tackifying resin, terpene phenolic resin 803-L (Arakawa Chemical Industry Co., Ltd., softening point 145-160℃), and a certain amount of ethyl acetate were added. The mixture was mixed evenly and allowed to stand to defoam, resulting in an adhesive with a solid content of 25%.

[0078] The adhesive was applied to the surface of a 50 μm thick PET release film and placed in an oven at 110℃ for 2 minutes to form a 30 μm thick adhesive layer. The adhesive layer was then bonded to a 50 μm thick foam. The adhesive was then applied to the surface of another 36 μm thick PET release film and placed in an oven at 110℃ for 2 minutes to form a 30 μm thick adhesive layer. The adhesive layer was then bonded to the other side of the foam and cured in an oven at 50℃ for 3 days. After being removed and cooled to room temperature for 3 hours, the heat-resistant adhesive tape was obtained.

[0079] Example 2 This embodiment is based on Example 1, with the only difference being the amount of some components in the adhesive. The preparation method and solid content are the same as in Example 1, and the specific differences are as follows: The mixture consists of 60 g of the second copolymer, 1 g of Dercolyte LTG terpene resin, 0.05 g of TDI crosslinking agent, and 1 g of terpene phenolic resin 803-L.

[0080] Example 3 This embodiment is based on Example 1, with the only difference being the amount of some components in the adhesive. The preparation method and solid content are the same as in Example 1, and the specific differences are as follows: 140 g of the second copolymer, 10 g of Dercolyte LTG terpene resin, 2 g of TDI crosslinking agent, and 10 g of terpene phenolic resin 803-L.

[0081] Example 4 This embodiment is based on Example 1, except that 128 g of glycerol (1.4 mol) is used instead of ethylene glycol in the preparation of the second copolymer in the adhesive. The preparation method and solid content of the tape are the same as in Example 1.

[0082] Example 5 group This set of examples is based on Example 1, with the only difference being the amount of certain components of the acrylate copolymer in the adhesive. The preparation method and solid content are the same as in Example 1, as detailed below: Example 5a: The amount of initiator was 1.5 g and the amount of dodecyl mercaptan was 0.15 g, and the weight average molecular weight of the acrylate copolymer was 2,000 g / mol. Example 5b: The amount of initiator was 0.7 g and the amount of dodecyl mercaptan was 0.08 g, and the weight average molecular weight of the acrylate copolymer was 12,000 g / mol. Example 5c: The amount of initiator was 2.3 g and the amount of dodecyl mercaptan was 0.2 g, and the weight average molecular weight of the acrylate copolymer was 1,000 g / mol. Example 5d: The amount of initiator was 0.6 g and the amount of dodecyl mercaptan was 0.05 g, and the weight average molecular weight of the acrylate copolymer was 14,000 g / mol.

[0083] Comparative Example 1 This comparative example group was prepared in accordance with Example 1, except that the amount of the second copolymer in the adhesive was different. The preparation method and solid content were the same as in Example 1, and the specific differences are as follows: Comparative Example 1a: without the second copolymer; Comparative Example 1b: The amount of the second copolymer used was 50 g; Comparative Example 1c: The amount of the second copolymer used was 150 g.

[0084] Comparative Example 2 This comparative example is based on Example 1, except that the adhesive does not contain acrylate copolymers, and its preparation method and solid content are the same as in Example 1.

[0085] Comparative Example 3 Groups This comparative example group was prepared in accordance with Example 1, except that the amount of the first tackifying resin in the adhesive was different. The preparation method and solid content were the same as in Example 1. The specific differences are as follows: Comparative Example 3a: Dercolyte LTG without terpene resin; Comparative Example 3b: The amount of terpene resin Dercolyte LTG used was 12 g; Comparative Example 3c: The amount of terpene resin Dercolyte LTG used was 0.5 g.

[0086] Comparative Example 4 Groups This comparative example group was prepared in accordance with Example 1, except that the amount of the second tackifying resin in the adhesive was different. The preparation method and solid content were the same as in Example 1. The specific differences are as follows: Comparative Example 4a: 803-L without terpene phenolic resin; Comparative Example 4b: The amount of terpene phenolic resin 803-L used was 12 g; Comparative Example 4c: The amount of terpene phenolic resin 803-L used was 0.5 g.

[0087] Comparative Example 5 Groups This comparative example group was conducted in accordance with Example 1, except that the type of the first or second tackifying resin in the adhesive was different. The preparation method and solid content were the same as in Example 1, and the specific differences are as follows: Comparative Example 5a: The first tackifying resin was replaced by an equal weight of rosin resin GB-75 (manufacturer: Arakawa Chemical Industry Co., Ltd., Japan, softening point 70-80℃). Comparative Example 5b: The second tackifying resin was replaced by an equal weight of rosin resin A-75 (manufacturer: Arakawa Chemical Industry Co., Ltd., Japan, softening point 70-80℃).

[0088] Test case The tapes prepared in the above embodiments and comparative examples were tested as follows, and the test results are shown in Table 1.

[0089] 1. 180° peel strength: The test was conducted according to the national standard GB / T 2792-2014 "Test Method for Peel Strength of Adhesive Tape". A 100 mm × 25 mm strip of adhesive tape was taken, and after peeling off the release film on one side, it was pasted onto a 25 μm PET film. After peeling off the release film on the other side, it was pasted onto a SUS304 steel plate. The tape was rolled back and forth twice with a 1 kg stainless steel roller at a speed of 600 mm / min to obtain the test sample. The 180° peel strength of the test sample was tested under the following different conditions, with a peel speed of 300 mm / min, expressed as gf / mm. (1) The test sample is placed at room temperature (RT, 23±1℃, 50±5%RH) for 30 min before testing. The peel force requirements are different for different application scenarios. Generally speaking, the peel force is not less than 3,200 gf / mm. (2) After placing the test sample at room temperature for 30 min, place it in an oven at 75℃ for 15 min. After taking it out, test the peel strength after the first heating. Generally speaking, if the peel strength does not exceed 400 gf / mm, it is easy to peel. (3) After peeling off the test strip in step (2) above, attach it to the steel plate in the same way, and test its peel force after the first re-adhesion after placing it at room temperature for 2 hours. (4) After peeling off the test strip in step (2) above, attach it to the steel plate in the same way and place it at room temperature for 2 h. Then, test its peel strength after the second heating in accordance with operation (2). (5) After peeling off the test strip in step (4) above, attach it to the steel plate in the same way, and test its peel force after the second re-adhesion after placing it at room temperature for 2 hours. (6) After peeling off the test strip in step (4) above, attach it to the steel plate in the same way and place it at room temperature for 2 h. Then, test its peel strength after the third heating in accordance with operation (2).

[0090] 2. Holding power test: The test was conducted according to the national standard GB / T 4851-2014 "Test method for holding power of adhesive tape". A 75 mm × 25 mm strip of adhesive tape was taken, and after peeling off the release film on one side, it was pasted onto a 25 μm PET film. After peeling off the release film on the other side, it was pasted onto a SUS304 steel plate. The pasting area was 25 mm × 25 mm. The sample was rolled back and forth twice with a 2 kg rubber roller at a speed of 600 mm / min to obtain the test sample. The test sample was placed at room temperature for 30 min, then placed vertically on the test rack with a 1 kg weight suspended below. The slip distance of the tape was recorded after 24 h. The test sample was placed at room temperature for 30 minutes, then placed vertically on the test frame. A 1 kg weight was suspended at 80°C, and the time it took for the tape to fall was recorded.

[0091] Table 1 Performance test results of different embodiments and comparative examples

[0092] The test results above show that the heat-reducing adhesive composition of the present invention, by introducing a second polymer containing selenium-selenium bond polymerization, causes the selenium-selenium bonds in the molecular chain to break and exchange under heating conditions of 70-80°C, destroying the molecular cross-linking network structure, shortening the molecular chain and increasing its fluidity, thus achieving the effect of heat-reducing tack. Furthermore, it has good tackiness after heat-reducing tack and can be reused multiple times. The addition of an appropriate amount of low softening point first tackifying resin can effectively improve the heat-reducing tack effect. The introduction of an appropriate amount of acrylate copolymer and high softening point second tackifying resin can effectively improve the adhesive's tackiness.

[0093] The test results of Example 5 show that by limiting the weight-average molecular weight of the acrylate copolymer within a certain range, an adhesive with a balanced heat-reducing effect and holding power can be obtained. If the weight-average molecular weight of the acrylate copolymer is too high, the degree of molecular chain entanglement will increase, resulting in a lower peel force before heat-reducing and a higher peel force after heat-reducing. If the weight-average molecular weight of the acrylate copolymer is too low, the holding power of the adhesive will decrease, which is not conducive to bonding.

[0094] The test results of Comparative Example 1 show that if the second copolymer is not added, the high-temperature peel force is still very high and there is no heat-reducing effect; if the amount of the second copolymer is too low, the high-temperature peel force and high-temperature holding power are still relatively large, and the heat-reducing effect is poor; if the amount of the second copolymer is too high, the room temperature peel force is significantly reduced, affecting its bonding effect.

[0095] The test results of Comparative Example 2 show that the room temperature peel strength is significantly reduced if the acrylate copolymer is not added.

[0096] The test results of the three groups show that if the first tackifying resin with a low softening point is not added or its dosage is too low, the high-temperature peel force will still be too high, which is not conducive to peeling; if the dosage of the first tackifying resin with a low softening point is too high, the room temperature tack will be poor.

[0097] The test results of the four groups show that if a second tackifying resin with a high softening point is not added or its dosage is too low, the room temperature peel force will decrease; if the dosage of the second tackifying resin with a high softening point is too high, the high temperature peel force and high temperature holding power will be high, and the heat-reducing effect will be poor.

[0098] The test results of the five groups show that if the softening point of the first tackifying resin is too high, the peel force after heating will be high, which is not conducive to heat reduction; if the softening point of the second tackifying resin is too low, the tackiness at room temperature will decrease.

[0099] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A heat-resistant adhesive composition, characterized in that, Includes the following components by weight: 100 parts of the first copolymer 60-140 parts of the second copolymer 1-10 parts of the first tackifying resin 1-10 parts of the second tackifying resin Crosslinking agent 0.05-2 parts, Wherein, the first copolymer is an acrylate copolymer, the monomers of the second copolymer are bonded by selenium-selenium bonds, the softening point of the first tackifying resin is ≤70℃, and the softening point of the second tackifying resin is >90℃.

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

3. The heat-reducing adhesive composition according to claim 1 or 2, characterized in that, Based on a total monomer weight of 100 wt% in the acrylate copolymer, it contains 75-95 wt% of alkyl (meth)acrylate with 1-14 alkyl carbon atoms and 5-25 wt% of polar monomers containing hydroxyl groups.

4. The heat-reducing adhesive composition according to claim 1, characterized in that, The monomers of the second copolymer are obtained by ring-opening oxidation of polyols and selenolactones.

5. The heat-reducing adhesive composition according to claim 4, characterized in that, The selenolactones include γ-selenobutyrolactone.

6. The heat-reducing adhesive composition according to claim 5, characterized in that, The polyol is ethylene glycol, and the polymer monomer structure of the second copolymer is shown in formula (1): Equation (1).

7. The heat-reducing adhesive composition according to claim 5, characterized in that, The polyol is glycerol, and the polymer monomer structure of the second copolymer is shown in formula (2) below: Equation (2).

8. The heat-reducing adhesive composition according to claim 1, characterized in that, The first tackifying resin and the second tackifying resin are independently selected from at least one of terpene resins, rosin and rosin-modified resins, and petroleum resins.

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

10. A heat-resistant, non-stick product, characterized in that, Includes a heat-resistant adhesive layer; said heat-resistant adhesive layer is made from the adhesive of claim 9, or contains a heat-resistant adhesive composition of any one of claims 1 to 8.

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