Solvent-free adhesive composition, low-stripping noise adhesive tape and preparation method of low-stripping noise adhesive tape

Abstract

The invention relates to a solvent-free adhesive composition, a low-stripping noise adhesive tape and a preparation method of the low-stripping noise adhesive tape. The solventless adhesive composition includes a urethane acrylate oligomer, a polyether acrylate, and an ultraviolet light initiator. Comprising an adhesive layer prepared from the solvent-free adhesive composition has excellent removal performance, low-noise removal can be realized, and the sustainable development concept of environmental protection and energy conservation is met.

Description

Technical Field

[0001] The present invention relates to the technical field of adhesives or tapes, and particularly to a solvent-free adhesive composition, a low-peel noise tape made from the solvent-free adhesive composition, and a preparation method thereof. Background Art

[0002] With the development of electronic devices, the requirements for removable tapes used for packaging and protecting electronic devices are getting higher and higher. Specifically, such applications require the tape to have the following properties: 1) excellent removal performance on the target substrate, capable of being removed without residue; 2) relatively stable peel force at different removal speeds; 3) low-noise or noiseless removal can be achieved; and 4) the adhesive formulation preferably does not contain organic solvents and is suitable for simple methods such as screen printing or flexographic printing processes for coating. Low-noise removal, residue-free removal, and stable peel force are the keys to a good customer experience during the removal of packaging and protection tapes.

[0003] Currently, silicone-based adhesives can achieve low-noise removal and have excellent removal performance. However, silicone-based adhesive tapes for packaging and protecting electronic products usually include five-layer structures such as a first release layer, a first adhesive layer (usually an acrylic adhesive), a substrate layer, a second adhesive layer (usually an organosilicon adhesive), and a second release layer (usually a high-cost fluorine release film), with a complex preparation process and serious material waste. During the specific application process of this silicone-based adhesive tape, it is also necessary to die-cut the above silicone-based adhesive tape, remove the original release film and replace the release film for the manufacturing process, and then bond it to the applied substrate layer. This process consumes a large amount of time, materials, and electrical energy, resulting in waste of time and cost. In addition, silicone-based adhesives usually require the use of organic solvents and toxic catalysts, so their environmental friendliness is poor and it is difficult to meet the needs of customers with high requirements for environmental protection indicators. In addition, another common adhesive currently used for packaging and protecting electronic products is acrylic-based adhesive, but acrylic-based adhesives have the problem of being difficult to achieve low-noise removal.

[0004] Therefore, it is necessary to develop a tape that combines excellent removal performance, can achieve low-noise removal, saves time, materials, and electrical energy, and simplifies the application process, as well as a solvent-free and printable adhesive composition for preparing such a tape, to meet the application requirements of continuously developing electronic devices and conform to the sustainable development concept of environmental protection and energy conservation. Summary of the Invention

[0005] The object of the present invention is to provide a solvent-free adhesive composition that combines excellent removal performance, can achieve low-noise removal, and is healthy and environmentally friendly. The formulation of the solvent-free adhesive composition does not contain organic solvents and its glue viscosity is appropriate, which can solve the problems of poor environmental friendliness and cumbersome application processes of commonly used adhesives on the market.

[0006] Another object of the present invention is to provide a tape that combines excellent removal performance, enables low-noise removal, and is healthy and environmentally friendly. The tape has a simplified combined structure, excellent removal performance, low peeling noise, and stable peeling force performance.

[0007] The above object of the present invention is achieved by the following technical solutions.

[0008] On the one hand, the present invention provides a solvent-free adhesive composition, comprising: a polyurethane acrylate oligomer, a polyether acrylate, and a UV initiator, and optionally further comprising a monofunctional acrylate.

[0009] Optionally, based on the total weight of the polyurethane acrylate oligomer, the polyether acrylate, and the monofunctional acrylate being 100 parts by mass, the content of the polyurethane acrylate oligomer is 35 to 65 parts by mass, preferably 35 to 55 parts by mass, more preferably 40 to 55 parts by mass; the content of the polyether acrylate is 20 to 60 parts by mass, preferably 35 to 60 parts by mass, more preferably 45 to 56 parts by mass; and the content of the monofunctional acrylate is 0 to 45 parts by mass, preferably 0 to 40 parts by mass, more preferably 0 to 30 parts by mass.

[0010] Optionally, the acrylate functionality of the polyurethane acrylate oligomer is 1 to 2, preferably 1 to 1.5, more preferably 1 to 1.3, specifically 1 and 1.3.

[0011] Optionally, the acrylic functionality of the polyether acrylate is 2.

[0012] Optionally, the polyether acrylate is the polyether acrylate represented by formula (1):

[0013]

[0014] Wherein, R is one selected from -CH2CH2-, -CH2CH2CH2-, -CH2CH(CH3)-, -CH2CH2CH2CH2-, and -CH2CH2CH2CH2CH2CH2-.

[0015] Optionally, the degree of polymerization n of the polyether acrylate is 5 to 30, preferably 6 to 20, more preferably 6 to 15.

[0016] On the other hand, the present invention provides a tape with low peeling noise, comprising a substrate and an adhesive layer, and the adhesive layer is formed from the above solvent-free adhesive composition.

[0017] In another aspect, the present invention provides a method for preparing a tape with low peeling noise, comprising: coating the above solvent-free adhesive composition on a substrate, and preparing the tape with low peeling noise after curing.

[0018] Optionally, the coating is screen printing or flexographic printing.

[0019] Optionally, the curing is carried out by ultraviolet light.

[0020] The solvent-free adhesive composition, low-noise tape and its preparation method according to the embodiments of the present invention can produce the following beneficial technical effects:

[0021] By using the solvent-free adhesive composition provided by the present invention to replace common solvent-based adhesives such as silicone adhesives, the adhesive can have low peeling noise while being more environmentally friendly; moreover, the solvent-free adhesive composition of the present invention can be used to prepare an environmentally friendly screen protection tape through processes such as printing, so that the tape can have a simplified two-layer or three-layer structure, improving the environmental friendliness of the tape product while having low peeling noise; in addition, by using the solvent-free adhesive composition of the present invention to coat on a substrate to prepare a tape product, bonding can be carried out without further slitting, replacing the release film and laminating the application substrate, further reducing the consumption of plastics and adhesives, simplifying the preparation process, saving time and energy, and further improving the environmental friendliness of the low-peeling-noise tape product. Description of the Drawings

[0022] Figure 1 It is a schematic diagram of the tape with a two-layer structure in the present invention.

[0023] Figure 2 It is a schematic diagram of the tape with a three-layer structure in the present invention.

[0024] Figure 3 It is a schematic diagram of the five-layer structure of a commercially available silicone / acrylic double-sided tape (i.e., the reference example AB tape in the present invention). Detailed Embodiments

[0025] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions of the present invention in conjunction with the following detailed embodiments. Obviously, the described detailed embodiments are part of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art without creative efforts based on the described embodiments of the present invention belong to the scope of protection of the present invention.

[0026] According to one aspect of the present invention, there is provided a solvent-free adhesive composition, comprising: a polyurethane acrylate oligomer, a polyether acrylate, and a UV initiator, and optionally further comprising a monofunctional acrylate. The solvent-free adhesive composition according to the present invention does not contain solvents, that is, it does not contain solvents added for adjusting the viscosity of the adhesive or for dissolving the main components of the adhesive, and preferably does not contain additionally added organic solvents. Therefore, the solvent-free adhesive composition according to the present invention can not only be removed with low noise and without residue, but also has environmental protection advantages such as no VOC volatilization, low-energy curing, and recyclability compared with conventional silicone adhesives.

[0027] According to a preferred embodiment of the present invention, based on the total weight of the polyurethane acrylate oligomer, the polyether acrylate, and the monofunctional acrylate being 100 parts by mass, the content of the polyurethane acrylate oligomer is 35 to 65 parts by mass, preferably 35 to 55 parts by mass, more preferably 40 to 55 parts by mass, and specifically can be 55; the content of the polyether acrylate according to the present invention is 20 to 60 parts by mass, preferably 35 to 60 parts by mass, more preferably 45 to 56 parts by mass, and specifically can be 45 or 56 parts by mass; and the content of the monofunctional acrylate is 0 to 45 parts by mass, preferably 0 to 40 parts by mass, more preferably 0 to 30 parts by mass, and specifically can be 0 parts by mass.

[0028] According to a preferred embodiment of the present invention, based on the total weight of the polyurethane acrylate oligomer, the polyether acrylate, and the monofunctional acrylate being 100 parts by mass, the content of the UV initiator is 0.2 to 10 parts by mass, preferably 1 to 6 parts by mass, more preferably 2 to 5 parts by mass.

[0029] According to a preferred embodiment of the present invention, the acrylate functionality of the polyurethane acrylate oligomer is 1 to 2, further preferably 1 to 1.5, more preferably 1 to 1.3, and specifically the functionality can be 1 and 1.3.

[0030] According to a preferred embodiment of the present invention, the glass transition temperature (Tg) of the polyurethane acrylate oligomer is less than or equal to -40 °C, preferably less than or equal to -50 °C, more preferably less than or equal to -60 °C.

[0031] According to a preferred embodiment of the present invention, the polyurethane acrylate oligomer includes, but is not limited to, one or more of DM5400 (Double Bond Chemical), BR3641AJ (Bomar Chemical), and BR3741AJ (Bomar Chemical).

[0032] According to a preferred embodiment of the present invention, the polyether acrylate is the polyether acrylate represented by formula (1):

[0033]

[0034] Among them, the group R is one selected from -CH2CH2-, -CH2CH2CH2-, -CH2CH(CH3)-, -CH2CH2CH2CH2- and -CH2CH2CH2CH2CH2CH2-.

[0035] According to a preferred embodiment of the present invention, the degree of polymerization n of the polyether acrylate is 5 to 30, preferably the degree of polymerization n is 6 to 20, and more preferably the degree of polymerization n is 6 to 15.

[0036] According to a preferred embodiment of the present invention, the polyether acrylate includes but is not limited to one or more of polyethylene glycol diacrylate, poly-1,2-propanediol diacrylate, poly-1,3-propanediol diacrylate, poly-1,4-butanediol diacrylate or poly-1,6-hexanediol diacrylate.

[0037] According to a preferred embodiment of the present invention, the glass transition temperature (Tg) of the monofunctional acrylate is less than or equal to -40 °C, preferably less than or equal to -50 °C, and more preferably less than or equal to -60 °C.

[0038] According to a preferred embodiment of the present invention, the monofunctional acrylate is a monoalkyl acrylate. Specifically, the monofunctional acrylate according to the present invention includes but is not limited to one or more of 2-ethylhexyl acrylate, 2-octyl acrylate, n-octyl acrylate, isooctyl acrylate, n-butyl acrylate, isobutyl acrylate, n-hexyl acrylate, n-heptyl acrylate, isodecyl acrylate, dodecyl acrylate, acrylic C 8-10 mixed ester and heptadecyl acrylate.

[0039] According to a preferred embodiment of the present invention, the ultraviolet light initiator is a cleavage type initiator. Preferably, the ultraviolet light initiator includes but is not limited to low-yellowing cleavage type photoinitiators such as phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, ethyl 2,4,6-trimethylbenzoyl phenylphosphonate and 1-hydroxy-cyclohexyl-phenyl ketone.

[0040] According to a preferred embodiment of the present invention, the solvent-free adhesive composition of the present invention may further contain an antifoaming agent. Preferably, the antifoaming agent is a solvent-free antifoaming agent. Specifically, the antifoaming agent includes but is not limited to one or more of BYK1790 and BYK067A of BYK Company in Germany.

[0041] On the other hand, the present invention provides a method for preparing a solvent-free adhesive composition, which includes: adding a polyurethane acrylate oligomer, a polyether acrylate, a UV initiator, and optionally a monofunctional acrylate and an antifoaming agent into a mixing container according to a formulation ratio, and stirring and mixing uniformly under the condition of no UV light to obtain a completely homogeneous adhesive composition. Preferably, it is stirred sufficiently with a stirrer at a rotation speed of 200 - 800 revolutions per minute to form a homogeneous liquid.

[0042] The solvent-free adhesive composition prepared according to the method of the present invention preferably has a viscosity range of 400 cps to 10,000 cps. According to conventional experiments, when the viscosity of the adhesive composition is lower than 400 cps, the adhesive composition will flow too easily after printing, and thus the adhesive composition will easily overflow during the processing, resulting in deformation of the edges of the tape pattern; when the viscosity of the adhesive composition is higher than 10,000 cps, the adhesive composition will not flow or level easily after printing, which will cause the surface of the finally prepared tape to easily appear orange peel or bubble holes, etc.

[0043] The glass transition temperature (Tg) of the solvent-free adhesive composition prepared according to the method of the present invention is less than or equal to -20 °C, preferably less than or equal to -25 °C, and more preferably less than or equal to -30 °C. The glass transition temperature (Tg) of this adhesive composition is calculated according to the Fox formula. The glass transition temperature (Tg) refers to the temperature at which an amorphous polymer changes from a glassy state to a highly elastic state. Tg has a direct relationship with the flexibility of the molecular chain. The lower Tg indicates the greater the flexibility of the molecular chain of the substance. Therefore, the Tg of the solvent-free adhesive composition of the present invention within the above range can further ensure that the adhesive layer prepared therefrom has appropriate peel force and initial adhesion performance, etc. during daily use.

[0044] On the other hand, the present invention also provides a tape with low peel stability, which includes a substrate and an adhesive layer made of the solvent-free adhesive composition according to the present invention. The substrate layer is paper, a PET film, a polyolefin film, a TPU film, a composite material film, etc.; the release layer is a release film of transparent materials such as a PET release film, a PP release film, etc. Preferably, the tape further includes a release layer.

[0045] The tape prepared by using the solvent-free adhesive composition according to the present invention can have a simple structure of 2 layers (a substrate with a release layer on the back, an adhesive layer) or 3 layers (a substrate, an adhesive layer, a release film), without the need to be combined with common PET layers, silicone adhesive layers, etc. Therefore, the tape according to the present invention can reduce material consumption and does not contain plastic components.

[0046] As shown in the attached Figure 1As shown, the tape (a) with a two-layer structure prepared by the present invention includes an upper adhesive layer (1) prepared from a solventless adhesive composition and a lower protective film substrate layer (2), and the back surface of the protective film substrate layer can be subjected to a release treatment. As attached Figure 2 As shown, the tape (b) with a three-layer structure prepared by the present invention includes an upper release layer (1'), a middle adhesive layer (2') prepared from a solventless adhesive composition, and a lower protective film substrate layer (3').

[0047] The structure of the commercially available silicone / acrylic double-sided tape (reference example AB tape of the present invention) is as attached Figure 3 As shown, the double-sided tape generally includes a five-layer structure. The first layer structure (2-1) is a release layer, the second layer structure (2-2) is a high-adhesion adhesive layer, the third layer structure (2-3) is a tape PET substrate layer, the fourth layer structure (2-4) is a low-adhesion adhesive layer (B side, such as a silicone layer), and the fifth layer structure (2-5) is a release layer.

[0048] On the other hand, the present invention provides a method for preparing a tape with low peeling noise, including: coating the solventless adhesive composition according to the present invention on a substrate, and preparing the tape with low peeling noise after curing. Preferably, the coating is screen printing or flexographic printing. More preferably, the curing is carried out by ultraviolet light. Specifically, the solventless adhesive composition configured according to the above method is coated on the substrate layer in a specific pattern, and after covering the release film on the adhesive layer, a high-pressure mercury lamp or an LED lamp is used to cure the adhesive layer to obtain a UV-cured acrylic adhesive tape.

[0049] The solventless adhesive composition, low-noise tape and its preparation method according to the embodiments of the present invention can produce the following beneficial technical effects, that is: by using the solventless adhesive composition provided by the present invention to replace the solvent-based adhesives such as commonly used silicone adhesives, the adhesive can have low peeling noise while being more environmentally friendly; moreover, the solventless adhesive composition of the present invention can be used to prepare an environmentally friendly screen protection tape through processes such as printing, so that the tape can have a simplified two-layer or three-layer structure, and while having low peeling noise, it can improve the environmental friendliness of the tape product; in addition, by using the solventless adhesive composition of the present invention to coat on a substrate to prepare a tape product, it is not necessary to further slit, replace the release film and press-fit the application substrate for bonding, further reducing the consumption of plastics and adhesives, simplifying the preparation process, saving time and energy, and further improving the environmental friendliness of the low-peeling noise tape product.

[0050] Examples

[0051] Embodiments of the present invention are merely used to exemplarily describe the technical solutions of the present invention, but it does not mean that the technical solutions of the present invention are limited to these specific embodiments.

[0052] Embodiments of the present invention adopt the following test methods to test the peel strength, peel noise, and removability (or residual glue after peeling) of the tape.

[0053] 1. Test method

[0054] (1) 180° peel strength test

[0055] The present invention tests the 180° peel strength of the tape on a glass plate, and the specific test method is as follows.

[0056] The peel strength of the present invention is measured under the conditions of a temperature of 23°C ± 1°C and a relative humidity of 50% ± 5%. The tape test sample is cut into a size of 25 mm × 150 mm and adhered to a glass plate with a water contact angle of 110 ± 5° and a surface roughness Ra = 0.009 ± 0.001. Before measurement, the surface of the glass plate is cleaned and conditioned with an organic cleaning agent. Then, the side of the tape facing away from the glass plate is lined with a 25-μm or other thickness PET or PVC plastic film to prevent the stretching or deformation of the adhesive layer during the peeling process. Then, the test sample is roll-pressed on the glass plate in the following manner: a 2-kg roller is used to roll back and forth on the tape to be tested 2 times at a rolling rate of 600 mm / min. After the rolling treatment, the glass plate is immediately inserted into a ZwickRoell tensile testing machine to allow the test sample to be peeled at an angle of 180°. The peeling force is measured using this testing machine (sensor: 100 N) at low and high speeds of 300 mm / min and 24,000 mm / min, respectively. The test results of each sample are represented by the average value (N / cm) of three measurement results.

[0057] (2) Peel noise test

[0058] The present invention tests the peel noise of the tape on a glass plate, and the specific test method is as follows.

[0059] Cut the tape sample into a size of 25 mm × 120 mm and adhere it to a glass plate with a water contact angle of 110 ± 5° and a surface roughness Ra = 0.009 ± 0.001. Clean and condition the surface of the glass plate with an organic cleaning agent before measurement. After rolling once with a rubber roller, then use a 2 kg roller to roll back and forth on the tape 2 times at a rolling rate of 600 mm / min, and let it stand for 20 min. Under the condition that the ambient noise is lower than 50 dB, place the probe of the noise meter (Sima noise meter AR844) 40 cm away from the sample, hold one end of the glass plate with one hand to stabilize the glass plate, and lift the starting end of the tape 135° with the other hand, then peel the test sample at a speed of 24,000 mm / min, and measure the peeling noise. The test result of each sample is represented by the average value of the peeling noises measured separately 3 times.

[0060] (3) Removability test

[0061] Cut the sample into a size of 25 mm × 120 mm and adhere it to a glass plate with a water contact angle of 110 ± 5° and a surface roughness Ra = 0.009 ± 0.001. Clean and condition the surface of the glass plate with an organic cleaning agent before measurement. After rolling once with a rubber roller, then use a 2 kg roller to roll back and forth on the tape 2 times at a rolling rate of 600 mm / min, and let it stand for 20 min. Place the sample in a damp heat box, take it out after placing it at 85 °C and 85% humidity for 72 hours. After placing it at room temperature for 2 hours, conduct the removability measurement of the sample. Hold one end of the glass plate with one hand to stabilize the glass plate, and lift the starting end of the tape 135° with the other hand, then peel the test sample at a speed of 24,000 mm / min. Subsequently, under natural light, visually observe whether there is residual glue on the surface of the adhered glass plate; and under strong light of 500 lumens, visually observe whether there is a ghost on the surface of the adhered glass plate. The test result of each sample is represented by the average result of the residual glue and ghost observed separately 3 times.

[0062] 2. Raw materials and preparation processes used in the examples

[0063] 2.1 Raw materials used in the examples

[0064] The raw materials used in the examples of the present invention, their abbreviations and detailed information are shown in Table 1 below.

[0065] Table 1. Raw materials used in the examples and comparative examples of the present invention

[0066]

[0067] 2.2 Preparation processes of the adhesive composition and tape of the examples

[0068] (1) Preparation process of the solvent-free adhesive composition

[0069] Weigh the polyurethane acrylate oligomer, polyether acrylate, monofunctional acrylate, and ultraviolet initiator according to the required formulation ratios and add them to a container. Stir well at a speed of 200 - 800 revolutions per minute using a stirrer at room temperature to obtain a completely homogeneous solution. The obtained adhesive composition has a viscosity range of 400 cps - 10,000 cps.

[0070] (2) Preparation process of low-noise release tape

[0071] Prepare the tape using the printing and coating method. Specifically, screen printing or flexographic printing can be used to coat the adhesive composition prepared according to the above method in a specific pattern on the substrate layer. After covering the release film on the adhesive layer, use a high-pressure mercury lamp or an LED lamp to cure the adhesive layer to obtain a UV-cured acrylic adhesive tape. The high-pressure mercury lamp or LED lamp provides UVA light with a wavelength of 365 - 395 nm, and the total UV energy is 800 - 4000 mJ / cm 2 .

[0072] 3. Examples and comparative examples

[0073] Examples 1 - 3

[0074] Weigh 45 parts by mass of poly(1,2-propylene glycol) (400) diacrylate and 1 part by mass of Omnirad 819, and respectively weigh 55 parts by mass of different types of polyurethane acrylate oligomers (DM5400, BR3641AJ, and BR3741AJ) as shown in Table 2, and add them to a mixing container. Stir at a speed of 300 - 500 revolutions per minute using a stirrer at room temperature for 40 - 60 minutes to obtain a completely homogeneous solution, that is, the solvent-free adhesive compositions of Examples 1 - 3.

[0075] Coat the prepared adhesive composition in a specific pattern on the substrate layer by printing, and after covering the release film on the adhesive layer, use a high-pressure mercury lamp or an LED lamp to cure the adhesive layer to obtain the tapes of the adhesive compositions of Examples 1 - 3.

[0076] Examples 4 - 6

[0077] Weigh 55 parts by mass of BR3741AJ and 2 parts by mass of Omnirad TPO, and respectively weigh 45 parts by mass of different types of polyether acrylates (poly(1,2-propylene glycol) (700) diacrylate, polyethylene glycol (400) diacrylate, and poly(1,4-butylene glycol) (650) diacrylate) as shown in Table 2, and add them to a mixing container. Stir at a speed of 300 - 500 revolutions per minute using a stirrer at room temperature for 40 - 60 minutes to obtain a completely homogeneous solution, that is, the solvent-free adhesive compositions of Examples 4 - 6.

[0078] The tape preparation steps are the same as those in Examples 1 to 3.

[0079] Example 7

[0080] Weigh 55 parts by mass of BR3741AJ, 25 parts by mass of poly(1,2-propylene glycol)(400) diacrylate, 20 parts by mass of polyethylene glycol(400) diacrylate, and 2 parts by mass of Omnirad TPO, and add them into a mixing container. Stir at a speed of 300 - 500 revolutions per minute for 40 - 60 minutes at room temperature to obtain a completely homogeneous solution, which is the solvent-free adhesive composition of Example 7.

[0081] The tape preparation steps are the same as those in Examples 1 to 3.

[0082] Example 8

[0083] Weigh 35 parts by mass of DM5400, 20 parts by mass of BR3641AJ, 45 parts by mass of poly(1,4-butylene glycol)(650) diacrylate, 1 part by mass of Omnirad TPO, and 3 parts by mass of Omnirad 184, and add them into a mixing container. Stir at a speed of 300 - 500 revolutions per minute for 40 - 60 minutes at room temperature to obtain a completely homogeneous solution, which is the solvent-free adhesive composition of Example 8.

[0084] The tape preparation steps are the same as those in Examples 1 to 3.

[0085] Example 9

[0086] Weigh 55 parts by mass of BR3741AJ, 25 parts by mass of polyethylene glycol(400) diacrylate, 20 parts by mass of n-butyl acrylate, and 2 parts by mass of Omnirad TPO, and add them into a mixing container. Stir at a speed of 300 - 500 revolutions per minute for 40 - 60 minutes at room temperature to obtain a completely homogeneous solution, which is the solvent-free adhesive composition of Example 9.

[0087] The tape preparation steps are the same as those in Examples 1 to 3.

[0088] Example 10

[0089] Weigh 44 parts by mass of BR3741AJ, 56 parts by mass of poly(1,2-propylene glycol)(400) diacrylate, and 5 parts by mass of Omnirad 184, and add them into a mixing container. Stir at a speed of 300 - 500 revolutions per minute for 40 - 60 minutes at room temperature to obtain a completely homogeneous solution, which is the solvent-free adhesive composition of Example 10.

[0090] The tape preparation steps are the same as those in Examples 1 to 3.

[0091] Example 11

[0092] Weigh 38 parts by mass of DM5400, 42 parts by mass of poly(1,4-butanediol) (650) diacrylate, 20 parts by mass of 2-ethylhexyl acrylate, 1 part by mass of Omnirad TPO, and 3 parts by mass of Omnirad 184, and add them into a mixing container. Stir at a speed of 300 - 500 revolutions per minute for 40 - 60 minutes at room temperature to obtain a completely homogeneous solution, which is the solvent-free adhesive composition of Example 11.

[0093] The tape preparation steps are the same as those in Examples 1 to 3.

[0094] Example 12

[0095] Weigh 60 parts by mass of DM5400, 36 parts by mass of polyethylene glycol (400) diacrylate, 4 parts by mass of 2-ethylhexyl acrylate, and 5 parts by mass of Omnirad 184, and add them into a mixing container. Stir at a speed of 300 - 500 revolutions per minute for 40 - 60 minutes at room temperature to obtain a completely homogeneous solution, which is the solvent-free adhesive composition of Example 12.

[0096] The tape preparation steps are the same as those in Examples 1 to 3.

[0097] Example 13

[0098] Weigh 40 parts by mass of DM5400, 29 parts by mass of poly(1,2-propanediol) (400) diacrylate, 41 parts by mass of 2-octyl acrylate, and 5 parts by mass of Omnirad 184, and add them into a mixing container. Stir at a speed of 300 - 500 revolutions per minute for 40 - 60 minutes at room temperature to obtain a completely homogeneous solution, which is the solvent-free adhesive composition of Example 13.

[0099] The tape preparation steps are the same as those in Examples 1 to 3.

[0100] Comparative Example 1

[0101] Weigh 35 parts by mass of DM5400, 65 parts by mass of poly(1,2-propanediol) (400) diacrylate, and 2.5 parts by mass of Omnirad 819, and add them into a mixing container. Stir at a speed of 300 - 500 revolutions per minute for 40 - 60 minutes at room temperature to obtain a completely homogeneous solution, which is the solvent-free adhesive composition of Comparative Example 1.

[0102] The tape preparation steps are the same as those in Examples 1 to 3.

[0103] Comparative Example 2

[0104] Weigh 55 parts by mass of BR3641AJ, 45 parts by mass of poly(1,2-propylene glycol) (200) diacrylate, and 1 part by mass of Omnirad 819, and add them into a mixing container. Stir at a speed of 300 - 500 revolutions per minute for 40 - 60 minutes at room temperature to obtain a completely homogeneous solution, which is the solvent-free adhesive composition of Comparative Example 2.

[0105] The tape preparation steps are the same as those in Examples 1 to 3.

[0106] Comparative Example 3

[0107] Weigh 55 parts by mass of BR3741AJ, 45 parts by mass of polyethylene glycol (350) monacrylate, and 1 part by mass of Omnirad 819, and add them into a mixing container. Stir at a speed of 300 - 500 revolutions per minute for 40 - 60 minutes at room temperature to obtain a completely homogeneous solution, which is the solvent-free adhesive composition of Comparative Example 3.

[0108] The tape preparation steps are the same as those in Examples 1 to 3.

[0109] Comparative Example 4

[0110] Weigh 55 parts by mass of BR3741AJ, 15 parts by mass of polyethylene glycol (400) diacrylate, 30 parts by mass of 2-ethylhexyl acrylate, and 2 parts by mass of Omnirad TPO, and add them into a mixing container. Stir at a speed of 300 - 500 revolutions per minute for 40 - 60 minutes at room temperature to obtain a completely homogeneous solution, which is the solvent-free adhesive composition of Comparative Example 4.

[0111] The tape preparation steps are the same as those in Examples 1 to 3.

[0112] Comparative Example 5

[0113] Weigh 25 parts by mass of DM5400, 25 parts by mass of poly(1,2-propylene glycol) (400) diacrylate, 25 parts by mass of n-butyl acrylate, 25 parts by mass of 2-ethylhexyl acrylate, and 5 parts by mass of Omnirad 184, and add them into a mixing container. Stir at a speed of 300 - 500 revolutions per minute for 40 - 60 minutes at room temperature to obtain a completely homogeneous solution, which is the solvent-free adhesive composition of Comparative Example 5.

[0114] The tape preparation steps are the same as those in Examples 1 to 3.

[0115] Comparative Example 6

[0116] Weigh 75 parts by mass of DM5400, 25 parts by mass of polyethylene glycol (400) diacrylate, and 5 parts by mass of Omnirad 184, and add them into a mixing container. Stir at a speed of 300 - 500 revolutions per minute for 40 - 60 minutes at room temperature to obtain a completely homogeneous solution, thus obtaining the solvent-free adhesive composition of Comparative Example 6.

[0117] The tape preparation steps are the same as those in Examples 1 - 3.

[0118] Reference Example AB Tape (Commercially available silicone / acrylic double-sided tape)

[0119] Coat a solvent-based acrylic copolymer adhesive (A side) and a solvent-based silicone adhesive solution (B side) on both sides of a PET film respectively, dry them respectively and cover with a release film, and finally obtain an AB tape with a five-layer structure. Die-cut the AB tape according to the specific patterns described in Examples 1 - 3, so that the reference example and Examples 1 - 13 and Comparative Examples 1 - 6 have the same pattern. The A side of the AB tape serves to fix the protective film substrate layer.

[0120] The tests on the relevant properties of the reference example are mainly carried out on the B side coated with the solvent-based silicone adhesive.

[0121] Table 2. Contents of each component in the examples

[0122]

[0123] Table 3. Contents of each component in the comparative examples

[0124]

[0125] 4. Influence of different component contents on the properties of the tape

[0126] Table 4. Test results of tape performance in examples and comparative examples

[0127]

[0128] *ND indicates that the peel strength cannot be tested, and its peel strength is lower than the detection limit.

[0129] As can be seen from the test result table 4 of the examples in Table 2 and the comparative examples in Table 3: Compared with Comparative Examples 1-6, the tapes prepared in Examples 1-13 of the present invention have reduced peel noise (58-69 dB) and a stable ratio of high-speed / low-speed peel force (4.1-9.5); compared with the peel noise (67 dB) and the ratio of high-speed / low-speed peel force (23.2) of the reference example tapes commonly used in the market, the tapes prepared in Examples 1-13 of the present invention have better performance than the reference examples, and simplify the product structure and reduce material loss.

[0130] Further analysis of the test results in Table 4 above reveals that: when the content of the polyurethane acrylate oligomer is less than 35 parts by mass (Comparative Example 5) or higher than 65 parts by mass (Comparative Example 6), the viscosity of the glue of the obtained adhesive composition exceeds the allowable range of the printing process, and the peel noise of the tape prepared from this adhesive composition is relatively high (72 dB); when the content of the polyether acrylate is less than 20 parts by mass (Comparative Example 4) or higher than 60 parts by mass (Comparative Example 1), the ratio of the low-speed peel force to the high-speed peel force of the obtained tape is abnormal, and thus the peel force stability is poor; when the content of the monofunctional acrylate is higher than 45 parts by mass (Comparative Example 5), the viscosity of the glue of the obtained adhesive composition exceeds the allowable range of the printing process, and the peel noise is relatively high (72 dB), and thus it is impossible to prepare a tape and suppress the peel noise by a simple process such as printing. In contrast, when the content of the polyurethane acrylate oligomer is 35-65 parts by mass, the content of the polyether acrylate is 20-60 parts by mass, and the content of the monofunctional acrylate is 0-45 parts by mass, the obtained tape has excellent removal performance, low peel noise and stable peel force.

[0131] In addition, when using a polyether acrylate with a polymerization degree of 4 (Comparative Example 2), the peel noise of the obtained tape is too high; or when using a polyether acrylate with a functionality of 1 (Comparative Example 3), the ratio of the high-speed / low-speed peel force of the tape made is too high, the peel force stability is poor, and there is residual glue when peeling the tape. In contrast, when using a polyether acrylate with an acrylic functionality of 2, the obtained tape has excellent removal performance, low peel noise and stable peel force.

[0132] In summary, the solvent-free adhesive composition prepared using the polyurethane acrylate oligomer and polyether acrylate within the content ranges as described in the present invention, or the polyurethane acrylate oligomer, polyether acrylate and monofunctional acrylate, etc., exhibits excellent low peel noise and a stable ratio of high-speed peel force to low-speed peel force.

Claims

1. A solventless adhesive composition, comprising: A polyurethane acrylate oligomer, a polyether acrylate, and a photoinitiator, and optionally further including a monofunctional acrylate.

2. The solventless adhesive composition according to claim 1, characterized in that, Based on the total weight of the polyurethane acrylate oligomer, the polyether acrylate, and the monofunctional acrylate being 100 parts by mass, the content of the polyurethane acrylate oligomer is 35 to 65 parts by mass, preferably 35 to 55 parts by mass, more preferably 40 to 55 parts by mass; the content of the polyether acrylate is 20 - 60 parts by mass, preferably 35 to 60 parts by mass, more preferably 45 to 56 parts by mass; and the content of the monofunctional acrylate is 0 to 45 parts by mass, preferably 0 to 40 parts by mass, more preferably 0 to 30 parts by mass.

3. The solventless adhesive composition according to claim 1 or 2, characterized in that, The acrylate functionality of the polyurethane acrylate oligomer is 1 to 2, preferably 1 to 1.5, more preferably 1 to 1.

3.

4. The solventless adhesive composition according to any one of claims 1 to 3, characterized in that, The acrylic functionality of the polyether acrylate is 2.

5. The solventless adhesive composition according to any one of claims 1 to 4, characterized in that, The polyether acrylate is the polyether acrylate represented by formula (1): Wherein, R is one selected from -CH2CH2-, -CH2CH2CH2-, -CH2CH(CH3)-, -CH2CH2CH2CH2-, and -CH2CH2CH2CH2CH2CH2-.

6. The solventless adhesive composition according to claim 5, characterized in that, The degree of polymerization n of the polyether acrylate is 5 to 30, preferably 6 to 20, more preferably 6 to 15.

7. A tape with low peel noise, comprising a substrate and an adhesive layer, wherein the adhesive layer is formed from the solventless adhesive composition according to any one of claims 1 to 6.

8. A method for preparing a tape with low peel noise, comprising: The solvent-free adhesive composition according to any one of claims 1 to 6 is coated on a substrate, and the tape with low peel noise is prepared after curing.

9. The method according to claim 8, characterized in that, The coating is screen printing or flexographic printing; preferably, the curing is carried out by ultraviolet light.

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