Ultraviolet-cured low-swelling adhesive and preparation method of components of ultraviolet-cured low-swelling adhesive

Abstract

The invention provides an ultraviolet-cured low-swelling adhesive and a preparation method of components of the ultraviolet-cured low-swelling adhesive. The low-swelling adhesive is prepared from the following components in percentage by weight: 30.0 to 60.0 percent of modified bifunctional polyurethane acrylate resin, 25.0 to 50.0 percent of modified monofunctional polyurethane acrylate resin, 3.0 to 15.0 percent of acrylate monomer, 0.1 to 5.0 percent of photoinitiator and 1.0 to 10.0 percent of other components. Through self-made synthesis of the modified monofunctional polyurethane acrylate resin and the modified bifunctional polyurethane acrylate resin, the adhesive has good compatibility with elastomer film materials such as TPEE and TPU, swelling and corrosion effects of the adhesive on the elastomer film materials are effectively reduced, the adhesive does not cause material deformation within several seconds, and the service life of the adhesive is prolonged. And the assembly requirement of the loudspeaker is met.

Description

Technical Field

[0001] The invention relates to the field of ultraviolet light curing adhesives, and in particular to a method for preparing an ultraviolet light curing low swelling adhesive and components thereof. Background Art

[0002] With the miniaturization and intelligent development of electronic products, micro speakers have been widely used in many fields such as mobile phones, headphones, tablets and laptops. Micro speakers are precision acoustic components assembled by multiple parts such as shell, front cover, diaphragm, coil, bracket, etc. through adhesive.

[0003] In the selection of diaphragm materials for micro speakers, traditional materials such as PEN, PAR, PEI, and PEEK have excellent corrosion resistance and can achieve good bonding effects with conventional UV-curing adhesives. However, with the continuous improvement of acoustic performance requirements, thermoplastic elastomer membrane materials such as TPEE, TPU, and acrylic rubber have gradually become a new direction for industry development due to their excellent mechanical elasticity, impact resistance, creep resistance, and bending fatigue resistance. These materials can bring better acoustic performance to micro speakers.

[0004] However, the current technical difficulty is that traditional UV-curing adhesives will cause the thermoplastic elastomer film material to swell and corrode, usually deforming within seconds, seriously affecting the assembly quality and performance of the speaker. Therefore, the development of low-swelling, high-adhesion UV-curing adhesives suitable for elastomer film materials such as TPEE, TPU, and acrylic rubber is of great significance for improving the assembly process and product performance of micro speakers. This includes not only the bonding of the elastomer film material to the voice coil, but also involves multiple aspects such as the composite application of the frame, elastic film, and metal film. Summary of the invention

[0005] The purpose of the present invention is to solve the problem that the ultraviolet light curing adhesive in the prior art may swell and deform.

[0006] The first aspect of the present invention provides a UV-curable low swelling adhesive, which comprises, by percentage:

[0007]

[0008]

[0009] Furthermore, the acrylic acid ester monomer is one or more of hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, isobornyl (meth)acrylate, tetrahydrofuran (meth)acrylate, isooctyl acrylate, isodecyl acrylate, alkoxydodecyl acrylate, vinyl neodecanoate, N,N-dimethylacrylamide, N,N-diethylacrylamide, acryloylmorpholine, 3,3,5-trimethylcyclohexyl acrylate, 2-phenoxyethyl acrylate, trimethylolpropane formal acrylate, and polycaprolactone modified acrylate.

[0010] Furthermore, the photoinitiator is one or more selected from the group consisting of 2-hydroxy-methylphenylpropane-1-one (1173), ethyl 2,4,6-trimethylbenzoylphenylphosphonate (TPO-L), 1-hydroxycyclohexylphenyl ketone (184), 2-methyl-1-(4-methylthiophenyl)-2-morpholinyl-1-propanone (907), benzoin dimethyl ether BDK (651), 2,4,6-trimethylbenzoyldiphenylphosphine oxide (TPO), isopropylthioxanthone (ITX), 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone (369), phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide (819), benzophenone (BP), camphorquinone (CQ), and ethyl 4-(dimethylamino)benzoate (EDAB).

[0011] Furthermore, the other components include a co-initiator, a thixotropic agent and a coupling agent.

[0012] Furthermore, the other components also include pigments with fluorescence detection or color display.

[0013] The second aspect of the present invention provides a method for preparing a modified bifunctional polyurethane acrylate resin, comprising:

[0014] Dehydrating difunctional polyols;

[0015] adding isocyanate and a catalyst to the dehydrated difunctional polyol to react;

[0016] Add hydroxy (meth) acrylate monomer to continue the reaction;

[0017] Measuring the NCO content in the system, and when the NCO content in the system is less than 0.05%, discharging the material to obtain a modified bifunctional polyurethane acrylate resin;

[0018] The amount of the catalyst used is 0.01-0.05% of the total material mass.

[0019] Further, dehydrating the difunctional polyol at 95° C. to 105° C. for 1 to 3 hours;

[0020] Adding isocyanate and catalyst to the dehydrated difunctional polyol to react at 80°C-85°C for 1-3 hours;

[0021] Hydroxy (meth) acrylate monomer was added and reacted at 80°C-85°C.

[0022] Furthermore, the difunctional polyol is a difunctional polyether polyol or polyester polyol having a hydroxyl value of 28 to 280 mgKOH / g.

[0023] Furthermore, the sum of the amounts of the isocyanate and the catalyst is 1.1-2.1 times that of the difunctional polyol; and the sum of the amounts of the hydroxy(meth)acrylate monomer is 0.1-1.1 times that of the difunctional polyol.

[0024] The third aspect of the present invention also provides a method for preparing a modified monofunctional polyurethane acrylate resin, comprising:

[0025] adding isocyanate and a catalyst to a hydroxy(meth)acrylate monomer to react;

[0026] Add low molecular weight polyol to continue the reaction;

[0027] Measuring the NCO content in the system, and when the NCO content in the system is less than 0.05%, discharging the material to obtain a modified monofunctional polyurethane acrylate resin;

[0028] Wherein, the dosage of the catalyst is 0.01-0.05% of the total material mass.

[0029] Further, adding isocyanate and a catalyst to the hydroxy (meth) acrylate monomer, and reacting at 75° C. to 85° C. for 1 to 3 hours;

[0030] Add low molecular weight polyol to continue the reaction;

[0031] Furthermore, the hydroxyl value of the low molecular weight polyol is 200 to 800 mgKOH / g.

[0032] Furthermore, the sum of the amounts of the isocyanate and the catalyst is 1.5-2 times that of the hydroxy(meth)acrylate monomer.

[0033] Compared with the prior art, the present invention includes at least the following beneficial effects: through the above-mentioned self-made synthetic modified monofunctional polyurethane acrylate resin and modified difunctional polyurethane acrylate resin, the adhesive has good compatibility with elastomeric film materials such as TPEE and TPU, effectively reducing the swelling and corrosion of the adhesive on the elastomeric film material, so that the adhesive will not cause material deformation within a few seconds, meeting the requirements of speaker assembly; the modified difunctional resin provides sufficient cross-linking density and enhances the cohesive strength of the adhesive layer, and the modified monofunctional resin provides suitable flexibility and improves the interfacial bonding force. The two resins are used in combination to improve the bonding strength between the adhesive and the elastomeric film material. DETAILED DESCRIPTION

[0034] The present invention will be described in more detail below, wherein preferred embodiments of the present invention are shown, and it should be understood that those skilled in the art can modify the present invention described herein, and still achieve the beneficial effects of the present invention. Therefore, the following description should be understood as being widely known to those skilled in the art, and not as a limitation of the present invention.

[0035] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0037] Embodiment 1

[0038] This embodiment provides a UV-curable low swelling adhesive, which comprises, by percentage:

[0039]

[0040] Specifically, the acrylic acid ester monomer is one or more of hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, isobornyl (meth)acrylate, tetrahydrofuran (meth)acrylate, isooctyl acrylate, isodecyl acrylate, alkoxydodecyl acrylate, vinyl neodecanoate, N,N-dimethylacrylamide, N,N-diethylacrylamide, acryloylmorpholine, 3,3,5-trimethylcyclohexyl acrylate, 2-phenoxyethyl acrylate, trimethylolpropane formal acrylate, and polycaprolactone modified acrylate.

[0041] Preferably, the acrylic ester monomer can be selected from one or a combination of two or more of the above acrylic ester monomers that do not contain a methyl group.

[0042] Specifically, the photoinitiator is one or more of 2-hydroxy-methylphenylpropane-1-one (1173), ethyl 2,4,6-trimethylbenzoylphenylphosphonate (TPO-L), 1-hydroxycyclohexylphenyl ketone (184), 2-methyl-1-(4-methylthiophenyl)-2-morpholinyl-1-propanone (907), benzoin dimethyl ether BDK (651), 2,4,6-trimethylbenzoyldiphenylphosphine oxide (TPO), isopropylthioxanthone (ITX), 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone (369), phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide (819), benzophenone (BP), camphorquinone (CQ), and ethyl 4-(dimethylamino)benzoate (EDAB).

[0043] Preferably, the photoinitiator is selected from a combination of 2-hydroxy-methylphenylpropane-1-one (1173), ethyl 2,4,6-trimethylbenzoylphenylphosphonate (TPO-L), and phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide (819).

[0044] Specifically, the other components include a co-initiator, a thixotropic agent and a coupling agent. The co-initiator is an aniline compound. The thixotropic agent is a hydrophobically modified silica, which can be selected from commercial products such as CAB-O-SIL TS720 from Cabot, Aerosil R202 from Evonik, and Coupling Agent from Wacker. The coupling agent is a silane coupling agent, and the commonly used silane coupling agents such as KH550, KH560, KH570, etc. can be selected.

[0045] Specifically, the other components also include pigments with fluorescence detection or color display, and preferably, fluorescent powder OB can be used.

[0046] Embodiment 2

[0047] This embodiment provides a method for preparing a modified bifunctional polyurethane acrylate resin, comprising:

[0048] Dehydrating difunctional polyols;

[0049] adding isocyanate and a catalyst to the dehydrated difunctional polyol to react;

[0050] Add hydroxy (meth) acrylate monomer to continue the reaction;

[0051] Measuring the NCO content in the system, and when the NCO content in the system is less than 0.05%, discharging the material to obtain a modified bifunctional polyurethane acrylate resin;

[0052] The amount of the catalyst used is 0.01-0.05% of the total material mass.

[0053] Specifically, n mol of difunctional polyol was put into a spherical reactor and the temperature was raised to 95°C.

[0054] ~105°C, vacuum dehydration for 1-3 hours. Preferably, dehydration at 105°C for 2 hours;

[0055] 1.1-2.1 nmol of isocyanate and catalyst are added to the dehydrated difunctional polyol and reacted at 80°C-85°C for 1-3 hours. Preferably, 1.5 nmol of isocyanate and catalyst are added and reacted at 85°C for 2 hours;

[0056] 0.1-1.1 nmol of hydroxy (meth) acrylate monomer is added to allow the reaction to continue at 80° C.-85° C. Preferably, 0.8 nmol of hydroxy (meth) acrylate monomer is added to allow the reaction to continue at 85° C.

[0057] Specifically, the difunctional polyol is a difunctional polyether polyol or polyester polyol having a hydroxyl value of 28 to 280 mgKOH / g.

[0058] Specifically, the sum of the amounts of the isocyanate and the catalyst is 1.1-2.1 times that of the difunctional polyol.

[0059] Specifically, the catalyst is one or a combination of organic tin compounds, organic bismuth compounds, organic bismuth zinc compounds, and amine compounds. Preferably, the catalyst is an organic tin compound.

[0060] Specifically, the hydroxy(meth)acrylate is one or a combination of hydroxyethyl(meth)acrylate, hydroxypropyl(meth)acrylate, and hydroxybutyl(meth)acrylate. Preferably, one or a combination of the above methyl-free hydroxyacrylates can be selected.

[0061] Specifically, the isocyanate is one or a combination of toluene diisocyanate (TDI), isophorone diisocyanate (IPDI), diphenylmethane diisocyanate (MDI), dicyclohexylmethane diisocyanate (H12MDI), hexamethylene diisocyanate (HDI). Preferably, the isocyanate is an aliphatic isocyanate.

[0062] Embodiment 3

[0063] This embodiment provides a method for preparing a modified monofunctional polyurethane acrylate resin, comprising:

[0064] adding isocyanate and a catalyst to a hydroxy(meth)acrylate monomer to react;

[0065] Add low molecular weight polyol to continue the reaction;

[0066] Measuring the NCO content in the system, and when the NCO content in the system is less than 0.05%, discharging the material to obtain a modified monofunctional polyurethane acrylate resin;

[0067] Wherein, the dosage of the catalyst is 0.01-0.05% of the total material mass.

[0068] Specifically, 1.5-2 nmol of isocyanate and catalyst are added to nmol of hydroxy (meth) acrylate monomer, and the mixture is reacted at 75°C-85°C for 1-3 hours. Preferably, 2 nmol of isocyanate and catalyst are added, and the mixture is reacted at 85°C for 2 hours;

[0069] The reaction was continued by adding low molecular weight polyol.

[0070] Specifically, the hydroxyl value of the low molecular weight polyol is 200 to 800 mgKOH / g.

[0071] Specifically, the catalyst is one or a combination of organic tin compounds, organic bismuth compounds, organic bismuth zinc compounds, and amine compounds. Preferably, the catalyst is an organic tin compound.

[0072] Specifically, the hydroxy(meth)acrylate is one or a combination of hydroxyethyl(meth)acrylate, hydroxypropyl(meth)acrylate, and hydroxybutyl(meth)acrylate. Preferably, one or a combination of the above methyl-free hydroxyacrylates can be selected.

[0073] Specifically, the isocyanate is one or a combination of toluene diisocyanate (TDI), isophorone diisocyanate (IPDI), diphenylmethane diisocyanate (MDI), dicyclohexylmethane diisocyanate (H12MDI), hexamethylene diisocyanate (HDI). Preferably, the isocyanate is an aliphatic isocyanate.

[0074] Embodiment 4

[0075] According to the material ratio in Table 1, 4 modified bifunctional polyurethane acrylate resins were prepared. The preparation method is as follows: weigh 100g of polyol in a round-bottom flask and dehydrate and dry at 105°C for 2 hours. After cooling to 85°C, add isocyanate and catalyst respectively according to the ratio in the table, and react at a constant temperature for 2 hours. Slowly add hydroxy acrylate and react at a constant temperature until the NCO value is less than 0.05%. In Table 1, VORANOL 2120P is a PPE polyol purchased from Dow Chemical, PTMG-2000 is a polyether polyol purchased from Mitsubishi Chemical; BY3030 is a polyester polyol purchased from Baiyuan Chemical; NJ-220 is a polyether polyol purchased from Ningwu Jurong.

[0076] Table 1

[0077] Modified bifunctional polyurethane acrylate resin A B C D VORANOL 2120P 100 0 0 0 PTMG-2000 0 100 0 0 BY3030 0 0 100 0 NJ-220 0 0 0 100 Isophorone diisocyanate (IPDI) 16.67 0 0 14.82 Dicyclohexylmethane diisocyanate (H12MDI) 0 19.67 0 0 Hexamethylene diisocyanate (HDI) 0 0 16.82 0 Hydroxypropyl Methacrylate 7.93 0 0 5.28 Hydroxybutyl acrylate 0 0 15.86 0 Hydroxyethyl acrylate 0 7.16 0 0 Dibutyltin dilaurate 0.02 0.03 0.04 0.02

[0078] According to the material ratio in Table 2, two modified monofunctional polyurethane acrylate resins were prepared: 1 mol of hydroxy acrylate monomer was put into a spherical reactor, 1 mol of isocyanate and 1 / 2 of the catalyst were added while stirring, the temperature was raised to 75-85°C, and the reaction was kept at a constant temperature for 2 hours. 1 mol of low molecular weight polyol and the remaining 1 / 2 of the catalyst were slowly added to the reactor, and the constant temperature stirring was continued until the NCO value dropped to 0.05%. Among them, the amount of catalyst was 0.01-0.05% of the total material mass.

[0079] Table 2

[0080] Modified monofunctional polyurethane acrylate resin E F Hydroxybutyl acrylate 144.17 144.17 Toluene diisocyanate (TDI) 0 174.16 Hexamethylene diisocyanate 168.19 0 2-Ethyl-1,3-hexanediol 146.23 0 Voranol WD 2104 0 415.56 Dibutyltin dilaurate 0.09 0.15

[0081] According to the material ratio in Table 3, a low swelling UV curing adhesive was prepared.

[0082] Table 3

[0083]

[0084]

[0085] In the comparative example, FS8982 is a commercial modified acrylate resin purchased from Runao Chemical.

[0086] Specifically, the specific steps for preparing the low swelling UV curing adhesive are: adding the resin, monomer and initiator according to the formula amount into a stirring kettle and mixing evenly, heating to 40-50°C and stirring at high speed until the solid material is completely dissolved, cooling to below 35°C, adding fumed silica, dispersing evenly at high speed, and discharging the material after vacuum degassing under stirring.

[0087] Experimental comparison tests were conducted on the experimental examples 1-4 and the comparative examples to examine the product properties.

[0088] The bonding strength test was carried out in accordance with the GB / T 7124-2008 adhesive tensile shear strength test method. First, the adhesive was applied to the bonding area of ​​the PC shear sheet, and the cut elastomer film was attached to the glue area. The PC substrate was illuminated at a light intensity of 100mW / cm 2 , and exposed to a UV curing device with a wavelength of 365nm for 30 seconds. Apply adhesive to another PC cut sheet and stick it to the area of ​​another elastic film. Pass through the PC substrate under a light intensity of 100mW / cm 2 , and then exposed to UV light curing equipment with a wavelength of 365nm for 30 seconds, and placed at room temperature for 24 hours. The shear strength was tested on a universal electronic tensile testing machine. Parameter settings: bonding area 25mm×12.5mm, 10KN sensor, test speed 5mm / min.

[0089] The swelling test method for the elastomer film is as follows: 2 mg of glue is applied on the edge of the TPEE film, and the time of swelling and deformation is recorded under a microscope.

[0090] The test results are shown in Table 4.

[0091] Table 4

[0092]

[0093] From the test results of the examples and comparative examples, the samples prepared with the traditional UV adhesive formula will swell the elastic film material quickly, and the bonding tensile shear strength is also high, but the elastic film will rupture and deform. Several embodiments of the present invention can achieve high bonding strength, and the swelling time is more than 2 minutes, which is sufficient to meet the requirements of assembly production.

[0094] The above specific examples are used to illustrate the present invention, which is only used to help understand the present invention and is not intended to limit the present invention. For those skilled in the art, according to the concept of the present invention, some simple deductions, modifications or substitutions can be made.

Claims

1. A UV-curable low swelling adhesive, characterized in that: Included by percentage:

2. The UV-curable low swelling adhesive according to claim 1, characterized in that: The acrylic acid ester monomers include hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, isobornyl (meth)acrylate, tetrahydrofuran (meth)acrylate, isooctyl acrylate, isodecyl acrylate, alkoxy dodecyl acrylate, vinyl neodecanoate, N,N-dimethylacrylamide, N,N-diethylacrylamide, acryloyl morpholine, 3,3,5-trimethylcyclohexyl acrylate, 2-phenoxyethyl acrylate One or more of ester, trimethylolpropane formal acrylate, and polycaprolactone modified acrylate.

3. The UV-curable low swelling adhesive according to claim 1, characterized in that: The photoinitiator is one or more of 2-hydroxy-methylphenylpropane-1-one (1173), ethyl 2,4,6-trimethylbenzoylphenylphosphonate (TPO-L), 1-hydroxycyclohexylphenyl ketone (184), 2-methyl-1-(4-methylthiophenyl)-2-morpholinyl-1-propanone (907), benzoin dimethyl ether BDK (651), 2,4,6-trimethylbenzoyldiphenylphosphine oxide (TPO), isopropylthioxanthone (ITX), 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone (369), phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide (819), benzophenone (BP), camphorquinone (CQ), and ethyl 4-(dimethylamino)benzoate (EDAB).

4. The UV-curable low swelling adhesive according to claim 1, characterized in that: The other components include a co-initiator, a thixotropic agent and a coupling agent.

5. The UV-curable low swelling adhesive according to claim 4, characterized in that: The other components also include pigments with fluorescence detection or color display.

6. A method for preparing a modified bifunctional polyurethane acrylate resin, characterized in that: include: Dehydrating difunctional polyols; adding isocyanate and a catalyst to the dehydrated difunctional polyol to react; Add hydroxy (meth) acrylate monomer to continue the reaction; Measuring the NCO content in the system, and when the NCO content in the system is less than 0.05%, discharging the material to obtain a modified bifunctional polyurethane acrylate resin; The amount of the catalyst used is 0.01-0.05% of the total material mass.

7. The method for preparing the modified bifunctional polyurethane acrylate resin according to claim 6, characterized in that: Dehydrating the difunctional polyol at 95° C. to 105° C. for 1 to 3 hours; Adding isocyanate and catalyst to the dehydrated difunctional polyol to react at 80°C-85°C for 1-3 hours; Hydroxy (meth) acrylate monomer was added and reacted at 80°C-85°C.

8. The method for preparing the modified bifunctional polyurethane acrylate resin according to claim 6, characterized in that: The bifunctional polyol is a bifunctional polyether polyol and a polyester polyol with a hydroxyl value of 28 to 280 mgKOH / g.

9. The method for preparing the modified bifunctional polyurethane acrylate resin according to claim 6, characterized in that: The sum of the amounts of the isocyanate and the catalyst is 1.1-2.1 times that of the difunctional polyol; The sum of the amounts of the hydroxy(meth)acrylate monomers is 0.1-1.1 times that of the difunctional polyol.

10. A method for preparing a modified monofunctional polyurethane acrylate resin, characterized in that: include: adding isocyanate and a catalyst to a hydroxy(meth)acrylate monomer to react; Add low molecular weight polyol to continue the reaction; Measuring the NCO content in the system, and when the NCO content in the system is less than 0.05%, discharging the material to obtain a modified monofunctional polyurethane acrylate resin; Wherein, the dosage of the catalyst is 0.01-0.05% of the total material mass.

11. The method for preparing the modified bifunctional polyurethane acrylate resin according to claim 10, characterized in that: Add isocyanate and catalyst to hydroxy (meth) acrylate monomer, and react at 75°C to 85°C for 1-3 hours; The reaction was continued by adding low molecular weight polyol.

12. The method for preparing the modified bifunctional polyurethane acrylate resin according to claim 10, characterized in that: The hydroxyl value of the low molecular weight polyol is 200 to 800 mgKOH / g.

13. The method for preparing the modified bifunctional polyurethane acrylate resin according to claim 10, characterized in that: The sum of the amounts of the isocyanate and the catalyst is 1.5-2 times that of the hydroxy(meth)acrylate monomer.

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