Adhesive film, acrylic adhesive tape and preparation method of adhesive film

Abstract

The invention discloses an adhesive film, an acrylic adhesive tape and a preparation method of the adhesive film, and the preparation method of the adhesive film comprises the following steps: uniformly mixing an acrylic polymer, a photoinitiator, an acrylic monomer and a polysiloxane surfactant to obtain a premix; stirring the premix in an inert atmosphere, and standing to obtain an adhesive solution; and after coating the adhesive solution, carrying out UV illumination cross-linking curing to obtain the adhesive film. According to the adhesive film, the acrylic adhesive tape and the preparation method of the adhesive film, the raw materials of the adhesive film are compounded and optimized, and particularly, the polysiloxane surfactant in the raw materials is matched and stirred, so that bubbles in the adhesive film are stable in structure, controllable in size and uniform in density.

Description

Technical Field

[0001] The invention belongs to the technical field of acrylic tapes, and in particular relates to an adhesive film, an acrylic tape and a method for preparing the adhesive film. Background Art

[0002] With the development of society and the increasing demands of people, foam tape is finding applications in a wide range of industries, including electronics, automotive manufacturing, construction and home furnishings, industrial energy, explosion-proof packaging for new energy batteries, and shock absorption for medical devices. Foam tape offers excellent sealing, insulation, temperature resistance, UV resistance, and solvent resistance. It can effectively absorb impact energy, reduce vibration transmission, firmly bond a variety of materials, and precisely conform to uneven surfaces. Its low density protects delicate electronic components from damage, simplifies equipment assembly processes, seals automotive doors and windows, and isolates electronic components, while also meeting lightweight design requirements and reducing production costs.

[0003] Existing UV foaming glue is often made using a chemical foaming method. However, high-viscosity UV foaming glue has disadvantages such as difficulty in controlling the foaming rate during the foaming process, resulting in unstable bubble structure and difficulty in controlling the foaming process.

[0004] The information disclosed in this background technology section is only intended to enhance understanding of the overall background of the invention and should not be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art. Summary of the Invention

[0005] The object of the present invention is to provide an adhesive film, an acrylic adhesive tape and a method for preparing the adhesive film, which have the advantages of stable bubble structure, controllable size and uniform density.

[0006] In order to achieve the above object, a specific embodiment of the present invention provides a technical solution as follows: a method for preparing an adhesive film, comprising the following steps:

[0007] The acrylic polymer, the photoinitiator, the acrylic monomer, and the polysiloxane surfactant are mixed uniformly in parts by mass to obtain a premix;

[0008] The premix is ​​stirred and allowed to stand in an inert atmosphere to obtain an adhesive solution;

[0009] After the adhesive solution is applied, it is cross-linked and cured by UV light to obtain an adhesive film.

[0010] In one or more embodiments of the present invention, in the step of stirring the premix in an inert atmosphere, the stirring rate is 500-3000 r / min and the stirring time is 10-180 min; and / or,

[0011] The standing time is 10-60 min.

[0012] In one or more embodiments of the present invention, the specific steps of stirring the premix in an inert atmosphere include:

[0013] The premix is ​​placed in a container, an inert gas is introduced into the container, and the mixture is stirred.

[0014] In one or more embodiments of the present invention, the volume flow rate of the inert gas introduced into the container is 10-200 L / min.

[0015] In one or more embodiments of the present invention, the premix comprises, by mass, 100 parts of acrylic polymer, 0.2-2 parts of photoinitiator, 10-50 parts of acrylic monomer, and 10-40 parts of polysiloxane surfactant; and / or,

[0016] The viscosity of the premix is ​​2000-20000 cps.

[0017] In one or more embodiments of the present invention, the acrylic polymer is prepared by polymerizing at least one monomer selected from the group consisting of acrylic acid, hydroxyethyl acrylate, methyl methacrylate, ethyl acrylate, and 2-ethylhexyl acrylate.

[0018] In one or more embodiments of the present invention, the photoinitiator is at least one of benzoin, benzoin isopropyl ether, benzoin isobutyl ether, benzoin n-butyl ether, 1-hydroxy-cyclohexyl phenyl ketone, trimethylbenzoyl diphenyl phosphine oxide, and α,α-diethylacetophenone.

[0019] In one or more embodiments of the present invention, the acrylic acid ester monomer is at least one of butyl acrylate, 2-phenoxyethyl acrylate, isooctyl acrylate, 1,6-hexanediol diacrylate, 1,4-propylene glycol diacrylate, ethoxylated bisphenol A dimethacrylate, trimethylolpropane triacrylate, isophorone diisocyanurate, trimethylolpropane triacrylate, and methoxy polyethylene glycol acrylate.

[0020] A specific embodiment of the present invention further provides an adhesive film prepared by the above-mentioned preparation method.

[0021] A specific embodiment of the present invention further provides an acrylic tape, comprising a laminated release layer and the above-mentioned adhesive film.

[0022] Compared with the prior art, the adhesive film, acrylic tape and method for preparing the adhesive film of the present invention optimize the compounding of the raw materials of the adhesive film, especially the mixing of the polysiloxane surfactant in the raw materials, so that the bubble structure in the adhesive film is stable, the size is controllable and the density is uniform. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0024] Figure 1 Flowchart of a method for preparing an adhesive film according to an embodiment of the present invention. DETAILED DESCRIPTION

[0025] In order to enable those skilled in the art to better understand the technical solutions of the present disclosure, the technical solutions in the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings in the embodiments of the present disclosure. Obviously, the described embodiments are only part of the embodiments of the present disclosure, not all of the embodiments. Based on the embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present disclosure.

[0026] As described in the background art, chemical foaming has problems such as difficulty in controlling the foaming rate, which leads to unstable bubble structure and difficulty in controlling the foaming process.

[0027] The preparation method of the adhesive film of the present invention is a physical foaming method. Compared with the chemical foaming method, it has the advantages of being simple and having controllable foaming size, density and stability.

[0028] like Figure 1 As shown, the method for preparing the adhesive film in one example of the present invention includes the following steps:

[0029] S1. Mix the acrylic polymer, photoinitiator, acrylic monomer, and polysiloxane surfactant uniformly in parts by mass to obtain a premix.

[0030] Specifically, in step S1, 100 parts of acrylic polymer, 0.2-2 parts of photoinitiator, 10-50 parts of acrylic monomer, and 10-40 parts of polysiloxane surfactant are mixed uniformly by mass to obtain a premix.

[0031] Specifically, the acrylic polymer is prepared by polymerizing at least one monomer selected from the group consisting of acrylic acid, hydroxyethyl acrylate, methyl methacrylate, ethyl acrylate, and 2-ethylhexyl acrylate.

[0032] Specifically, the photoinitiator is at least one of benzoin, benzoin isopropyl ether, benzoin isobutyl ether, benzoin n-butyl ether, 1-hydroxy-cyclohexyl phenyl ketone, trimethylbenzoyl diphenyl phosphine oxide, and alpha, alpha-diethylacetophenone.

[0033] Specifically, the acrylate monomer is at least one of butyl acrylate, 2-phenoxyethyl acrylate, isooctyl acrylate, 1,6-hexanediol diacrylate, 1,4-propanediol diacrylate, ethoxylated bisphenol A dimethacrylate, trimethylolpropane triacrylate, isophorone diisocyanurate, trimethylolpropane triacrylate, and methoxypolyethylene glycol acrylate.

[0034] Specifically, the polysiloxane surfactant can be any one of SD-221 (Jiangsu Sifeng New Material), SD-622 (Jiangsu Sifeng New Material), R301 (Jiahua Chemical), Magnasoft 310 (Maitian High-tech Material), and TSF4709 (Maitian High-tech Material).

[0035] Specifically, the viscosity of the premix is 2000-20000 cps.

[0036] S2, stirring and standing the premix in an inert atmosphere to obtain an adhesive solution.

[0037] Specifically, in step S2, the stirring rate is 500-3000 r / min, and the stirring time is 10-180 min.

[0038] Specifically, the standing time is 10-60 min.

[0039] Specifically, the specific steps of step S2 can be placing the premix in a container, introducing inert gas into the container, and stirring.

[0040] Preferably, the volume flow rate of the inert gas introduced into the container is 10-200 L / min.

[0041] S3, after coating the adhesive solution, UV light irradiation cross-linking and curing to obtain an adhesive film.

[0042] It can be understood that the UV light irradiation curing time is 30-120 s.

[0043] A specific embodiment of the present application also provides an adhesive film prepared by the above preparation method.

[0044] A specific embodiment of the present application also provides an acrylic adhesive tape, which comprises a release layer and an adhesive film as described above.

[0045] Specifically, the acrylic tape may include a first release layer, an adhesive film, and a second release layer stacked in sequence.

[0046] Preferably, the first release layer can be made of any one of PE, PET, and PI, with a thickness of 20-30 μm. The second release layer can be made of any one of PE, PET, PI, and BOPP, with a thickness of 30-50 μm. The thickness of the adhesive film is 500-1200 μm.

[0047] The following will describe in detail the adhesive film, acrylic adhesive tape and the preparation method of the adhesive film of the present invention in combination with specific embodiments and comparative examples.

[0048] Example 1

[0049] 100 parts of acrylic polymer (2-ethylhexyl acrylate), 1 part of photoinitiator (benzoin isopropyl ether), 20 parts of acrylic monomer (6-hexanediol diacrylate), and 20 parts of polysiloxane surfactant (SD-221) were stirred and mixed evenly, and then placed in a mechanical stirring device. After stirring, inert gas was introduced into the device at a stirring speed of 2000 r / min, a stirring time of 60 min, and an inert gas volume flow rate of 100 L / min. After stirring, the mixture was allowed to stand for 30 minutes to obtain an adhesive solution with a viscosity of 10,000 cps.

[0050] The adhesive solution was pumped into a coating machine and coated on a second release layer (PET film, 50 μm thick) while covering it with a first release layer (PE film, 25 μm thick). A light-curing process was then performed to produce an acrylic tape with uniform bubbles. The thickness of the film was 1000 μm.

[0051] Example 2

[0052] 100 parts of acrylic polymer (polymethyl methacrylate), 2 parts of photoinitiator (1-hydroxy-cyclohexylphenyl ketone), 50 parts of acrylic monomer (isooctyl acrylate), and 40 parts of polysiloxane surfactant (TSF4709) were stirred and mixed evenly, and then placed in a mechanical stirring device. After stirring, inert gas was introduced into the device at a stirring speed of 3000 r / min, a stirring time of 10 minutes, and an inert gas volume flow rate of 200 L / min. After stirring, the mixture was allowed to stand for 30 minutes to obtain an adhesive solution with a viscosity of 15000 cps.

[0053] The adhesive solution was pumped into a coating machine and coated on a second release layer (PET film, 50 μm thick) while covering it with a first release layer (PE film, 25 μm thick). A light-curing process was then performed to produce an acrylic tape with uniform bubbles. The thickness of the film was 1000 μm.

[0054] Example 3

[0055] 100 parts of acrylic polymer (hydroxyethyl acrylate), 0.2 parts of photoinitiator (α, α-diethylacetophenone), 10 parts of acrylic monomer (isophorone diisocyanurate), and 10 parts of polysiloxane surfactant (R301) were stirred and mixed uniformly, and then placed in a mechanical stirring device. After stirring, inert gas was introduced into the device at a stirring speed of 500 r / min, a stirring time of 180 min, and an inert gas volume flow rate of 10 L / min. After stirring, the mixture was allowed to stand for 30 minutes to obtain an adhesive solution with a viscosity of 8000 cps.

[0056] The adhesive solution was pumped into a coating machine and coated on a second release layer (PET film, 50 μm thick) while covering it with a first release layer (PE film, 25 μm thick). A light-curing process was then performed to produce an acrylic tape with uniform bubbles. The thickness of the film was 1000 μm.

[0057] Comparative Example 1

[0058] The process is basically the same as Example 1, except that no polysiloxane surfactant is added.

[0059] Comparative Example 2

[0060] The process is basically the same as Example 1, except that 60 parts of polysiloxane surfactant are added.

[0061] Comparative Example 3

[0062] The difference from Example 1 is that the mechanical stirring speed is 100 r / min.

[0063] Comparative Example 4

[0064] The difference from Example 1 is that the mechanical stirring speed is 4000 r / min.

[0065] Comparative Example 5

[0066] The difference from Example 1 is that the amount of inert gas passed is 5 L / min.

[0067] Comparative Example 6

[0068] The difference from Example 1 is that the amount of inert gas passed is 300 L / min.

[0069] Comparative Example 7

[0070] The difference from Example 1 is that the glue viscosity is 1000 cps.

[0071] Comparative Example 8

[0072] The difference from Example 1 is that the viscosity of the glue is 30,000 cps.

[0073] The acrylic tapes in the examples and comparative examples were tested as follows:

[0074] (1) Peel strength test: Use a peel strength tester to test the peel strength of acrylic tape to steel plate. The higher the peel strength, the stronger the adhesion.

[0075] (2) Average bubble diameter test: Cut the acrylic tape into 2mm×2mm samples and use a digital microscope to take 200x magnified photos to measure the bubble diameter in the coating direction (X direction), perpendicular to the coating direction (Y direction), and thickness direction (Z direction). Repeat the above operation 10 times and calculate the average value. The average bubble diameter test is completed.

[0076] (3) Z-direction impact strength test: Cut a square, frame-shaped sample (external dimensions 33 mm × 33 mm; side width 2.0 mm; internal dimensions 29 mm × 29 mm) from the tape to be tested. Adhere the sample to a PC frame (external dimensions 45 mm × 45 mm; side width 10 mm; internal dimensions 25 mm × 25 mm; thickness 3 mm). Adhere a 35 mm × 35 mm PC window to the other side of the double-sided tape. Adhere the PC frame, tape frame, and PC window in such a way that the geometric centers and diagonals are located above or overlap each other (corner on corner), respectively, and the bonding area is 248 mm. 2 . Press the bond at 248N for 5s and store for 24 hours. Immediately after storage, place the adhesive composite comprising the PC frame, tape and PC window on the sample holder with the protruding edge of the PC frame in such a way that the composite is oriented horizontally and the PC window is located below the frame. The sample holder is then centrally inserted into the predetermined socket of the "DuPont Impact Tester". Using an impact head weighing 190 grams, the circular impact geometry with a diameter of 20 mm is centered and flush on the window edge of the PC window. A weight of 150g guided on two guide rods is dropped vertically from a height of 5cm onto the composite consisting of the sample holder, sample and impact head arranged in this way. The height of the falling object is gradually increased by 5cm until the impact energy introduced by the impact load destroys the sample and the PC window is separated from the PC frame. Energy is calculated according to E(J) = height (m) × body weight (kg) × 9.81m / s 2 To calculate, an average of five samples per product were tested and the energy average was reported as a measure of the impact energy.

[0077] (4) XY-plane impact strength test: Cut a square, frame-shaped sample (external dimensions 33 mm × 33 mm; side width 2.0 mm; internal dimensions 29 mm × 29 mm) from the tape to be tested. Adhere the sample to a PC frame (external dimensions 45 mm × 45 mm; side width 10 mm; internal dimensions 25 mm × 25 mm; thickness 3 mm). Adhere a 35 mm × 35 mm PC window to the other side of the double-sided tape. Adhere the PC frame, tape frame, and PC window in such a way that the geometric centers and diagonals are located above or overlap each other (corner on corner), respectively, with a bonding area of ​​248 mm. 2 . Press the bond at 248N for 5s and store for 24 hours. Immediately after storage, place the adhesive composite comprising the PC frame, tape and PC window on the sample holder with the protruding edge of the PC frame in such a way that the composite is oriented horizontally. The sample holder is then centrally inserted into the predetermined socket of the "DuPont Impact Tester". Using a 300-gram impact head, a rectangular impact geometry with dimensions of 20mm×3mm is centered and flush with the upward end face of the PC window. A weight of 150g guided on two guide rods is dropped vertically from a height of 5cm onto the composite consisting of the sample holder, sample and impact head arranged in this way. The height of the falling object is gradually increased by 5cm until the impact energy introduced by the lateral impact load destroys the sample and the PC window is separated from the PC frame. Energy is calculated as E(J)=height(m)×weight(kg)×9.81m / s 2 To calculate, an average of five samples per product were tested and the energy average was reported as a measure of the impact energy.

[0078] Some of the results obtained from the above tests are shown in the following table:

[0079]

[0080] Combining Example 1, Example 2 and Example 3, the bubble size and peel strength in Example 1 are better, which shows that too high or too low cross-linking density has a greater impact on the bubbles.

[0081] In Example 1, Comparative Examples 1, and 2, excessive addition of a polysiloxane surfactant reduced bubble size, resulting in slightly higher peel strength and lower impact strength. Without the addition of a polysiloxane surfactant, bubbles coalesced into larger ones, forming defects (such as pits) on the tape surface, leading to reduced peel and impact strength in the pitted areas.

[0082] In combination with Example 1, Comparative Example 3 and Comparative Example 4, if the stirring speed is too low, it is difficult for the gas to enter the glue, resulting in larger bubble size, lower peel strength and impact strength; if the stirring speed is too high, the shear force is too large, resulting in defoaming and collapse of the bubbles, and lower peel strength and impact strength.

[0083] In combination with Example 1, Comparative Example 5 and Comparative Example 6, the lower ventilation volume results in a low foaming ratio, resulting in a tape bubble size, slightly lower peel strength, and reduced impact strength; the higher ventilation volume does not allow the gas to be dispersed in time, resulting in larger bubbles, lower peel strength, and reduced impact strength.

[0084] In combination with Example 1, Comparative Example 7 and Comparative Example 8, if the viscosity of the glue is too low, the bubbles will be unstable and easy to merge and float, resulting in a small amount of bubbles in the tape and reduced peel strength and impact strength; if the viscosity of the glue is too high, it will be difficult to introduce and disperse inert gas into the glue, resulting in a small amount of bubbles, larger bubble size, higher peel strength and lower impact strength.

[0085] As can be seen from the table above, Example 1 exhibits excellent bubble uniformity and surface impact absorption while maintaining excellent peel strength. The amount of polysiloxane surfactant, stirring speed, amount of inert gas, and adhesive viscosity affect bubble size and density, thereby affecting the film's impact resistance.

[0086] It will be apparent to those skilled in the art that the present disclosure is not limited to the details of the exemplary embodiments described above and that the present disclosure can be implemented in other specific forms without departing from the spirit or essential characteristics of the present disclosure. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the present disclosure is defined by the appended claims, not the foregoing description, and all variations within the meaning and range of equivalents of the claims are intended to be encompassed within the present disclosure. Any reference sign in a claim should not be construed as limiting the claim to which it relates.

[0087] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A method for preparing a film, characterized in that: The following steps are involved: Evenly mixing an acrylic polymer, a photoinitiator, an acrylic monomer, and a polysiloxane surfactant to obtain a premix; The premix is ​​stirred and allowed to stand in an inert atmosphere to obtain an adhesive solution; After the adhesive solution is applied, it is cross-linked and cured by UV light to obtain an adhesive film.

2. The method for preparing the adhesive film according to claim 1, wherein: In the step of stirring the premix in an inert atmosphere, the stirring rate is 500-3000 r / min and the stirring time is 10-180 min; and / or, The standing time is 10-60 min.

3. The method for preparing the adhesive film according to claim 1, wherein: The specific steps of stirring the premix in an inert atmosphere include: The premix is ​​placed in a container, an inert gas is introduced into the container, and the mixture is stirred.

4. The method for preparing the adhesive film according to claim 3, wherein: The volume flow rate of the inert gas introduced into the container is 10-200 L / min.

5. The method for preparing the adhesive film according to claim 1, wherein: The premix comprises, by mass, 100 parts of acrylic polymer, 0.2-2 parts of photoinitiator, 10-50 parts of acrylic monomer, and 10-40 parts of polysiloxane surfactant; and / or, The viscosity of the premix is ​​2000-20000 cps.

6. The method for preparing the adhesive film according to claim 1, wherein: The acrylic polymer is prepared by polymerizing at least one monomer selected from the group consisting of acrylic acid, hydroxyethyl acrylate, methyl methacrylate, ethyl acrylate, and 2-ethylhexyl acrylate.

7. The method for preparing the adhesive film according to claim 1, wherein: The photoinitiator is at least one of benzoin, benzoin isopropyl ether, benzoin isobutyl ether, benzoin n-butyl ether, 1-hydroxy-cyclohexyl phenyl ketone, trimethylbenzoyldiphenylphosphine oxide, and α,α-diethylacetophenone.

8. The method for preparing the adhesive film according to claim 1, wherein: The acrylic acid ester monomer is at least one of butyl acrylate, 2-phenoxyethyl acrylate, isooctyl acrylate, 1,6-hexanediol diacrylate, 1,4-propylene glycol diacrylate, ethoxylated bisphenol A dimethacrylate, trimethylolpropane triacrylate, isophorone diisocyanurate, trimethylolpropane triacrylate, and methoxy polyethylene glycol acrylate.

9. A film, characterized in that: The method is prepared according to any one of claims 1 to 8.

10. An acrylic tape, characterized in that: The invention comprises a release layer and the adhesive film as claimed in claim 9.

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