RU2311437C1 - Uv-strengthening glue composition, optical reading head with its using and optical recording/reproducing device comprising optical reading head - Google Patents

Abstract

FIELD: glue compositions.

SUBSTANCE: invention relates to UV-strengthening glue compositions used for gluing polymethylmethacrylate with metal. Proposed composition comprises oligourethane-acrylate representing product of interaction of oligobutadienediol of molecular mass 2000-3000 Da, aliphatic or aromatic diisocyanate and hydr(o)oxyalkylmethacrylate taken in the molar ratio = 1:2:2, reactive monomer-diluting agent representing a mixture of mono- and polyfunctional methacrylate, polymeric filling agent - polyethylene of high density with particles size below 50 mcm, photoinitiating agent, antioxidant of phenolic type and adhesion promoter - a mixture of chlorinated polyvinyl chloride with chlorine content 62-64 wt.-% and oxalic acid, and the composition comprises additionally thixotropic agent - aerosil with specific surface 175-380 m²/g and ester plasticizing agent. Invention provides the development of UV-strengthening glue composition showing the thixotropy coefficient K = 2-3, shrinkage 4%, not above, break off strength both in the parent state and after heat effect, moisture and temperature drop 1.5 MPa, not less, and stability in storage above one year. The composition can be used as adhesive in electronic devices, such as optical reading head, thin-film transistor - mesomorphic display and organic electroluminescent unit.

EFFECT: valuable properties of composition.

5 cl, 2 tbl, 5 dwg, 8 ex

Description

Technical field

The present invention relates to a UV-curable composition intended for bonding polymethylmethacrylate with a metal having thixotropicity, low shrinkage, increased adhesive strength and the ability to long-term storage without changing operational properties, and the use of this composition as an adhesive for electronic devices such as optical readout head, thin-film transistor - liquid crystal display (TFT-LCD) and organic electroluminescent element (EL).

State of the art

An analysis of the patent literature revealed a number of patents on UV-curable adhesives. So, the described composition of ultraviolet curing, used as an adhesive for optical disks (US patent No. 6337118, B32B 3/02, publ. 08.01.2002). The composition consists of 5-85 wt.% Oligourethane acrylate with various oligomeric blocks, including with ether and polybutadiene, 0.5-30 wt.% hydroxyalkyl methacrylates, 20-50 wt.% monofunctional diluent monomers (isobornyl methacrylate, derivatives of tricyclodecane, N-vinylamides, polyfunctional crosslinking agents, including triethylene glycol dimethacrylate, trimethyl glycol triant SR-350) and others, 1-10% of photoinitiators (Irgacure 184, 651, etc.). The composition contains silane adhesion promoters and functional additives.

The adhesive, according to the authors, quickly cures, has good heat and moisture resistance, has good adhesion to polymethyl methacrylate, polycarbonate, metals, although quantitative characteristics are not given in the patent.

However, this composition cannot be applied under the specific conditions required for the implementation of the invention, because it is not thixotropic, no filler is introduced into it, and therefore it should have increased shrinkage (at least 5-6%).

The prototype of the invention is a UV-curable composition using in the manufacture of DVDs for bonding polymer substrates of polycarbonate, polyacrylate, polyvinyl types with metals (Au, Ag, Al, etc.) (US patent No. 6017603, C08F 2/46, publ. 01/25/2000), consisting of 10-30 wt.% Bisphenol type epoxymethacrylate (m. 450-3000), 30-50 wt.% Oligourethane methacrylate (m. 400-10000) with simple and complex polyester, polycarbonate, etc. blocks 10-80 wt.% Methacrylate monomer (isobornyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, hydroxyethyl- (meth) acrylate / methoxyethyl methacrylate, etc.); 0.01-20 wt.% Photoinitiator ("Jrgacure 184, Jrgacure 1800). If necessary, polymers of high molecular weight are introduced into it, incl. polyvinyl type and the like. Silane adhesion promoters, an antioxidant, an excipient can be introduced into the composition. The composition has good adhesive strength with the above substrates, however, the shrinkage, as in other US patent No. 6472451, C08F 2/46, publ. 10/29/2002, also dedicated to the adhesive for DVD and additionally containing non-acrylate-type diluent monomer and thiol compound, is value> 5.4%. When using a polymer filler, for example, polyethylene, in the prototype, shrinkage can be reduced, but the adhesive strength will be reduced. Therefore, the composition of the prototype cannot be applied in the required optical devices.

Disclosure of invention

The authors were tasked with creating a UV-curable adhesive composition with a thixotropy coefficient of K = 2–3, shrinkage of not more than 4%, and tear-off strength for polymethylmethacrylate-metal substrates (steel 12X18H10T) both in the initial state and after exposure to heat and moisture , a temperature difference of at least 1.5 MPa and storage stability of ≥1 year.

To solve this problem, a UV curable composition is claimed, consisting of:

wt.% oligobutadiene urethane methacrylate 10-30 reactive diluent monomer - mixtures of mono- and polyfunctional methacrylates 32-46 polymer filler - high polyethylene density with particle size up to 50 microns 20-30 photo initiator 2.5-5.0 phenolic type antioxidant 0.005-0.02 chlorinated polyvinyl chloride containing chlorine 62-64 wt.% 3.0-10.0 oxalic acid 0.3-2.0 thixotropic agent - aerosil with specific surface 175-380 m ² / g 0.5-3.0 ester plasticizer 1.0-10.0.

As oligobutadiene urethane methacrylate, the product of the interaction of oligobutadiene diol with m.m 2000-3000, aliphatic or aromatic diisocyanate and hydroxyalkyl (meth) acrylate in a molar ratio of 1: 2: 2 is used. Oligobutadiene diol is the product of the polymerization of 1,3-butadiene with 1 / 4- and 1,2- addition of monomer units. Preferably, an oligomer containing ~ 30% of 1 / 4- and ~ 70% of 1,2-units is used.

Of the diisocyanates, hexamethylene diisocyanate and its substituted analogues, isophorondiisocyanate, 2,4-toluene diisocyanate, etc. are used.

The hydroxyalkyl methacrylate may be hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxybutyl methacrylate, etc.

Oligobutadiene urethane methacrylates are used both as individual compounds and as a mixture. A mixture of aliphatic and aromatic urethane acrylate in a weight ratio of 1-1.5: 1 is preferred.

The diluent monomer includes a mixture of monofunctional methacrylates with cyclic substituents (isobornyl, tetrahydrofurfuryl, dicyclopentenyloxyethyl), higher alcohol methacrylate (octyl methacrylate) and polyfunctional methacrylates (dimethacrylate triethylene glycol trimethol).

The adhesive contains a thixotropic agent - Aerosil with a surface of 175-380 m ² / g, which can be used in a mixture with BYK-410 or BYK-S-740, which improve the dispersibility of Aerosil in the composition. BYK-410 is a solution of modified urea with functional groups in p-methylpyrrolidone (www.familyhome.by), and BYK-S-740 is a composition of oxypolyesters with paraffin (http://chem.eurohim.ru).

As an ester plasticizer, the composition may contain dioctyl phthalate, 2-butoxyethyl adipate, benzyl-2-ethylhexyl adipate, etc.

The composition of the claimed UV-curable adhesive composition includes photoinitiators: Irgacure-184 (1-hydroxycyclohexyl-phenylketone), Irgacure-651 (2,2-dimethoxy-2-phenylacetophenone), Irgacure-819 (bis (2,4 / 6-trimethylbenzoyl ) phenylphosphinooxide), Darocur-1173 (2-hydroxy-2-methyl-1-phenylpropan-1-one), etc., as well as mixtures thereof.

As a phenolic antioxidant, the composition may contain p-methoxyphenol, ionol, hydroquinone, etc.

Next, an optical read head and a recording / reproducing drive using the aforementioned UV-curable adhesive composition will be described in detail. The optical read head of the present invention includes a base and optical elements that are adhered to the base using the aforementioned UV-curable adhesive composition as an adhesive. The configuration of the optical system in the optical read head of the present invention is shown in FIG. With reference to FIG. 1, the optical read head includes a light source 1 for emitting light with a predetermined wavelength, a grating 2 for diffusing light from the light source into a 0-order beam and a 1-order beam; a collimating lens 3 for creating fiber optic communications that are parallel to one another; a lens 9 for forming an optical spot on the recording surface of the optical disk 10; the main light detector 7 for receiving light reflected from the recording surface of the optical disk 10, and determining the information signal and the error signal. The number 4 indicates the coupler for the guide light emitted by the light source 1 to the lens 9, and the light reflected from the optical disk 10 to the main light detector 7. The concave lens 6 can be placed between the coupler 4 and the main light detector 7. The concave lens 6 is used for astigmatism correction. The coupler 5 is also responsible for the diffraction of the light directed towards the lens 9 towards the front light detector 8. The front light detector 8 is used to determine the light intensity. If the determined light intensity is less than or exceeds a predetermined level, then the intensity of the light emitted from the light source 1 is adjusted so that the light reaches the optical disk 10 with a force of a predetermined level.

Figure 2 shows an optical read head relative to an embodiment of the present invention. The optical read head includes an aluminum base. The aforementioned optical elements are placed at predetermined locations of the substrate for attachment to it using the UV curable adhesive composition of the present invention. For example, the grating 2 is fixed to the base grating holder, the laser diode is fixed to the base diode holder, and the coupler 5 and the collimating lens are directly attached to the base. The UV-curable adhesive composition of the present invention is applied to special places on the base or optical elements and exposed to ultraviolet radiation for curing.

Figure 3 shows the place of application of the UV-curable adhesive composition of the present invention when the lens is attached to the base in an optical read head. The lens attaches to the base drive blade. After the UV-curable adhesive composition of the present invention is applied to four points of the drive blade, the lens is placed and exposed to ultraviolet radiation to cure the composition.

Figure 4 shows the application site of the UV-curable adhesive composition of the present invention when the coupler is attached to the base in an optical read head. After the UV-curable adhesive composition of the present invention is applied to two points of the coupler, it is placed on the substrate and exposed to ultraviolet radiation to cure the composition.

5 shows an optical read / reproduce drive of the present invention. With reference to FIG. 5, the tray 30 is included in the track of the groove 20 in such a way that it slides into or out of the groove in the direction of arrow “A”. The tray 30 is equipped with a spindle motor 31 and a gripping base 33. The spindle motor 31 has a turntable 32 on its rotating axis. When the optical disk 10 is mounted on the turntable 32, the spindle motor 31 starts to rotate the optical disk 10. The grip base 33 slides in the radius direction (indicated by arrow "B") of the optical disk 10. The optical read head 40 is attached to the base of the grip 33 to access the recording the surface of the optical disk 10 and recording / reproducing information.

As can be seen from the above, the UV-curable adhesive composition of the present invention meets the requirements for low shrinkage and high adhesion. The adhesion with the base is excellent. In addition, when the composition of the present invention is used in microelectronics devices, such as an optical read head, a thin film transistor, a liquid crystal display, and organic electroluminescent elements, deformation and displacement do not occur. Therefore, the accuracy of the process is ensured. In addition, in the case of adding a thixotropic substance to the polymer composition, its ductility does not occur like gluten caramel. As a result, the decrease in the operation of electronic devices after applying adhesives to undesirable places is prevented.

The present invention is further described by examples, which are given to illustrate, but not to limit the scope of the claims. Examples 1-2 show methods for producing oligobutadiene urethane methacrylates, preferably used in the inventive UV-curable adhesive composition.

Example 1

Obtaining oligobutadiene urethane methacrylate OUMD-3000N

150 g of liquid oligobutadiene diol (Krasol LBH-2000, F. Kauchuk, Czech Republic) are loaded into the reactor and heated to 45-50 ° C with stirring. Then 18.6 g of hexamethylene diisocyanate are dosed at a rate of 1 g / min while maintaining a temperature of 55-60 ° C. After dosing, the reaction mass is stirred for 4.5-5 hours at 55-60 ° C until a content of isocyanate groups of 2.75% is reached and then cooled to 45-50 ° C. 17.76 g of monomethacrylate-propylene glycol is gradually added to the reactor with 0.093 g of tin dibutyl dicaprilate catalyst dissolved at a rate of 1 g / min. The temperature should not exceed 50-55 ° C. After that, the reaction mass is maintained with stirring for 7-8 hours at 55-60 ° C until the isocyanate groups are exhausted. 0.0186 g of p-methoxyphenol is charged and mixed for another 30 minutes.

The product is a viscous, colorless or slightly yellowish mass. Dynamic viscosity 66000 mPa · s.

Example 2

Obtaining oligobutadiene urethane methacrylate OUMD-3000T

The synthesis is carried out analogously to example 1 using 2,4-toluene diisocyanate as a diisocyanate.

Obtaining UV-curable composition (examples 3-9)

Mixing is carried out in a mixer with thorough mixing of the components shown in table 1.

Physico-mechanical properties of the UV cured composition

The tensile strength was determined on the adhesive joints of polymethylmethacrylate glass grade СО-120К (Russia) with a sample size of 50 × 50 × 6 mm with a cylindrical image of steel 12X18 HI OT with a diameter of 25 mm on an Instron tensile testing machine at a test speed of 20 mm per minute at + 25 ° FROM:

I - strength 24 hours after bonding,

II - strength after holding glued samples for 72 hours at + 60 ° C and 95% humidity,

III - strength after thermal cycling (20 cycles) at + 70 ° С (1 hour) ↔ -30 ° С (1 hour).

Shrinkage was determined by the ratio of the densities of the liquid adhesive and the polymer obtained from it.

The composition and properties of the compositions are shown in tables 1 and 2.

Table 1
Formulation Compositions Composition components Content, wt.% Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Example 9 According to the invention For comparison OUMD-3000N 8.1 14.2 20.1 - 8.1 8.1 8.1 OUMD-3000T 7.5 13.7 - 17.4 7.5 7.5 7.5 Isoborn methacrylate 15,2 12,4 15.0 - 15,2 15,2 15,2 Tetrahydrofurfuryl methacrylate - - - 28 - - - Triethylene glycol dimethacrylate - - 2.0 2,5 - - - Dicyclopentenyloxyethyl methacrylate 28,4 16.6 22.7 - 28,4 28,4 28,4 Trimethacrylate trimethylolpropane 0.5 1,0 - - 0.5 0.5 0.5 Octyl methacrylate 1.8 2.0 1/1 3.0 1.8 1.8 1.8 Chlorinated PVC with a chlorine content of 62-64 wt.% 4.2 3,5 5,6 8.0 4.2 4.2 Oxalic acid 0.7 0.9 1,5 1,2 - 0.7 - Acrylic acid - - - - 1,1 - - Dioctyl phthalate 1.8 - - - 1.8 1.8 1.8 Di-2-butoxyethyl adipate - 4.3 - 5.5 - - - Benzyl-2-ethylhexyl adipate - - 3.8 - - - - Aerosil A-175 1,6 0.8 2,5 2.0 1,6 1,6 1,6 BYK-410 0.1 0.1 0.1 0.1 0.1 0.1 0.1 BYK S-740 0, 8 0.7 0.8 0.7 0.4 0.8 0.8 Irgacure-184 2.9 4.2 - 2,3 2.9 2.9 2.9 Irgacure-651 0.7 - - - 0.7 0.7 0.7 Irgacure-819 - - - 1.3 - - - Darocur-1173 - - 3.8 - - - - High density polyethylene with particle sizes up to 50 microns 25.7 25.6 21.0 28.0 25.7 29.9 26,4 p-methoxyphenol 0.01 * 0.02 * - - 0.01 * 0.01 * 0.01 * Ionol - - - 0.01 * - - - Hydroquinone - - 0.05 * - - - - * parts by weight per 100 parts by weight composition

table 2
Properties of UV-curable adhesive composition The properties Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Example 9 Shrink% 3,7 3,5 3,7 3.6 3,7 3,7 3,7 Tear strength, MPa I 8.2 7.4 6.8 8.0 4.3 3,1 3.0 II 3.4 3.8 3.0 4.1 1.8 0.5 0.6 III 5,0 6.2 4,5 6.6 1.7 0.5 0, 6 Storage stability, year one one one one 0.5 - -

Table 2 shows that the claimed composition meets the specified technical requirements and surpasses the known composition in terms of shrinkage and adhesive strength.

Although the present invention is illustrated by examples of its preferred implementation, they in no way limit the claimed scope of the invention.

Thus, the composition according to the invention meets the advanced requirements and is fully suitable for use in electronic devices.

Claims (5)

1. UV-curable adhesive composition containing oligourethane acrylate, a reactive diluent monomer, a mixture of mono- and polyfunctional methacrylates, a polymer filler, a photoinitiator, a phenolic type antioxidant and an adhesion promoter, characterized in that it contains a chlorinated polychloride mixture as an adhesion promoter with a chlorine content of 62-64 wt.% and oxalic acid, as the oligourethane acrylate is the product of the interaction of oligobutadiene diol with m.m. 2000-3000, aliphatic or aromatic diisocyanate and hydroxyalkyl methacrylate, taken in molar ratios of 1: 2: 2, as a polymer filler - high density polyethylene with a particle size of up to 50 microns, and additionally includes a thixotropic agent - aerosil with a specific surface area of 175-380 m ² / g and ester plasticizer with the following ratio of components of the composition, wt.%: specified oligobutadiene urethane methacrylate 10-30 reactive diluent monomer 32-46 high density polyethylene 20-30 photo initiator 2.5-5.0 phenolic antioxidant 0.005-0.02 chlorinated polyvinyl chloride with a chlorine content of 62-64 wt.% 3.0-10.0 oxalic acid 0.3-2.0 aerosil 0.5-3.0 ester plasticizer 1.0-10.0 2. The composition according to claim 1, where the adhesion promoter means a mixture of chlorinated polyvinyl chloride with a chlorine content of 62-64% and oxalic acid, taken in a mass ratio of 10-5: 1. 3. An optical read head including a base and optical elements that are glued to the base using a UV curable adhesive composition according to claims 1 and 2. 4. The optical read head according to claim 3, where the optical elements include an optical diode, a grating, a collimating lens, a coupler, a reflecting mirror, a light detector, a frontal light detector, a lens, a concave lens, and a main cover. 5. The optical recording / reproducing device includes an optical reading head in accordance with paragraph 4.

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