KR100833197B1 - UV-curable adhesive composition, optical pick-up device using the same and optical recording/reproducing drive comprising the optical pick-up device - Google Patents

Abstract

The present invention relates to an ultraviolet curable adhesive composition used as a binder of polymethyl methacrylate and a metal and its use, wherein the composition has thixotropic properties, low shrinkage, high adhesive strength, and no change in service characteristics. It can be stored for a long time. For this reason, it is used as an adhesive agent for electronic devices, such as an optical pickup, TFT LCD, and an organic electroluminescent element.

Description

UV-curable adhesive composition, optical pick-up device using the same and optical recording / reproducing drive comprising the optical pick-up device }

The present invention relates to an ultraviolet curable adhesive composition used as an adhesive of polymethyl methacrylate and a metal, and to use thereof, wherein the ultraviolet ray has properties that can be stored for a long time without changing thixotropy properties, low shrinkage, high adhesive strength, and service properties. A curable adhesive certain thing and its use are related.

The composition according to the invention is used as an adhesive for electronic devices such as optical pickups, thin film transistor-liquid crystal semiconductor displays (TFT LCDs) and organic electroluminescent elements (EL) devices. .

Analysis of the patent literature has found a number of patents on ultraviolet curable adhesives. Therefore, an ultraviolet curable composition (US Patent No. 637118, B32B, published Jan. 8, 2002) used as an adhesive for optical discs is described. The composition is 5 to 85% by weight of oligourethane acrylate having various oligomeric blocks including ether and polybutadiene, 0.5 to 30% by weight of hydroxyalkyl methacrylate, and 20 to 50% of monofunctional monomer dilution (isobonyl Polyfunctional catalyzers including methacrylate, tricyclodecane derivatives, N-vinylamide, triethylene glycol dimethacrylate, trimethylolpropane trimethacrylate (SR-350) and others), 1-10% Photopolymerization initiators (Irgacure 184, 651 and others). The composition includes a silane adhesion promoter and a functional additive.

Although quantitative properties are not described in this patent, the patent says that the adhesive cures quickly, resists heat and moisture, and adheres well to polymethyl methacrylate, polycarbons, metals.

However, since the composition is free of thixotropic properties, it cannot be used under the specific conditions necessary for the realization of the present invention, and there is no filler added so the shrinkage rate (at least 5-6%) is very high.

Prior art in close proximity to the present invention is an ultraviolet curable composition used in the manufacture of DVDs for bonding polymer bases of polycarbonate, polyacrylate, polyvinyl types with metals (gold, silver, aluminum, etc.) (US Patent No.6017603). , C08F 2/46, published January 25, 2000), the composition comprising 10-30% by weight of epoxy methacrylate (molecular weight 450-3,000) of the bisphenol type, polyether and polyester, polycarbonate and other blocks Oligourethane methacrylate having 30 to 50% by weight (molecular weight 400 to 10,000), methacrylate monomer (isobonyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, hydrooxyethyl (meth) Acrylate, methoxyethyl methacrylate and others) 10 to 80% by weight, photopolymerization initiator (Irgacure 184, Irgacure 1800) 0.01 to 20% by weight.

If necessary, a polymer having a high molecular weight including a polyvinyl type or the like is introduced. The silane adhesion promoters, antioxidants and fillers in the composition can be changed. The composition has a high strength of adhesion to the base described above, but it can be applied to DVD as well as other US patents (No.6472451, published on October 29, 2002, C08F 2/46) and is non-acrylic (non- Additional acrylic diluents and thiol compounds are required, with a shrinkage of more than 5.4%. For example, the most similar prior art for the preparation of polymer fillers can lower the shrinkage when using polyethylene, but the adhesion strength is reduced. Thus there is a problem that even the compositions according to the prior art cannot be used in optical devices.

The UV curable adhesive composition according to the present invention has a thixotropic coefficient K = 2 to 3, shrinkage of 4% or less, between polymethyl methacrylate base-metal (metal 12X18H10T) even after initial temperature as well as irradiation with heat and moisture and temperature drop. Tensile strength is 1.5MPa or more, and can be stably stored for more than one year.

The ultraviolet curable adhesive composition according to the present invention includes the following components. (Unit: weight%)

Oligourethane methacrylate 10-30

Monomer-dilution 32-46

-Polymer filler 20-30

-Photopolymerization initiator 2.5-50

Antioxidant 0.005-0.02

-Polyvinyl chloride 3.0-10.0

Oxalic acid 0.3-2.0

Thixotropic 0.5-3.0

-Plasticizer 1.0-10.0

As the oligoethane methacrylate, a reaction product of polybutadienediol having a molecular weight of 2,000 to 3,000, an aliphatic having an molar ratio of 1: 2: 2, aromatic diisocyanate, and hydroxyalkyl (meth) acrylate is used. Here, polybutadienediol is a polymerization product of 1,3-butadiene containing monomer rings according to 1,4 and 1,2 addition reactions. It is also desirable to use oligomers comprising 30% of 1,4 units and 70% of 1,2 units.

Hexamethylene diisocyanate and its analogs, isophorone diisocyanate, 2,4-toluylene diisocyanate and others are used as diisocyanate. The hydroxyalkyl (meth) acrylate may be hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate and others.

Oligobutadiene urethane acrylates are used in the form of mixtures as well as in the form of individual compounds. The weight ratio of the mixture of aliphatic and aromatic urethane acrylates is preferably 1: 1 to 1.5: 1.

Monomer diluents include monofunctional methacrylates having isocyclic substituents (isobonyl-, tetrahydrofurfuryl-, dicyclopentenyloxyethyl-), methacrylates of higher alcohols (octyl methacrylate) and polyfunctional methacrylates. (Triethylene glycol dimethacrylate, trimethylolpropane trimethacrylate and others).

The components of the adhesive include thixotropic agents (e.g., aerosils with a specific surface of 175 to 380 m 2 / g), BYK-410, Texaper P-61, plasticizers (e.g., dioctyl phthalate) and photopolymerization initiators ( Irgacure 181, 651 or mixtures thereof).

As the poly filler, a high density powder polyethylene having a particle diameter of 50 µm is used.

In order to increase the adhesive strength of the compositions according to the invention a mixture consisting of PVC chloride and oxalic acid dissolved in a monomer of chlorine content 62-64% is proposed. It is preferable to use 3 to 10% by weight of PVC chloride and 0.3 to 2% of oxalic acid. Although this combination is not described above in this document, the bond strength increased unexpectedly when bonding polymethyl methacrylate and iron (12X18H10T). This is shown in Table 1 and Table 2.

Hereinafter, an optical pickup device and an optical recording / reproducing drive using the above-mentioned photocurable adhesive composition are described in detail. An optical pickup apparatus according to the present invention comprises a base and an optical element bonded to a predetermined position of the base using the above-mentioned photocurable adhesive composition which is an adhesive.

The configuration of the optical system of the optical pickup apparatus according to the present invention is shown in FIG. Referring to FIG. 1, a light source 1 emitting light of a predetermined wavelength, a grating 2 for dispersing light emitted from the light source 1 into a 0th order ray and a ± 1st order ray, and light waves parallel to each other collimating lens 3 for generating a light wave, an objective lens 9 for forming an optical spot on the recording surface of the optical disk 10, and light reflected from the recording surface of the optical disk 10 to receive information A main light detector 7 is shown which detects signals and error signals. Reference numeral 4 denotes a beam splitter which allows light emitted from the light source 1 to be incident on the objective lens 9 and light reflected on the optical disk 10 to be incident on the main light detector 7. The concave lens 6 may be placed between the beam splitter 4 and the main light detector 7. The concave lens 6 is used to correct astigmatism. The front light detector 8 is used to detect the power of light. When the intensity of the detected light is below or above the predetermined level, the power of the light emitted from the light source 1 is adjusted to allow light having a predetermined level of power to enter the optical disc 10. 2 shows an optical pickup device according to an embodiment of the present invention. The optical pickup device includes an aluminum base. The photocurable adhesive composition according to the present invention is used to place the above-described optical elements in a predetermined position on the base and to be fixed on the base. For example, the grating 2 is fixed on the grating holder of the base, the laser diode is fixed on the laser diode holder of the base, and the beam splitter 4 and the balance lens are fixed directly on the base. The photocurable adhesive composition according to the present invention is applied to a specific portion of the base or the optical element and irradiated with ultraviolet rays to cure.

Fig. 3 shows the part to which the photocurable adhesive composition according to the present invention is applied when the objective lens is adhered to the base of the optical pickup device. The objective lens is adhered to an actuator blade of the base. After the photocurable adhesive composition according to the invention is applied to four points of the actuator blade, the objective lens is placed thereon and ultraviolet rays are irradiated to cure the composition.

4 shows the part to which the photocurable adhesive composition according to the present invention is applied when the beam splitter is attached to the base of the optical pickup device. After the photocurable adhesive composition according to the invention is applied to two points of the beam splitter, the beam splitter is placed on the base and irradiated with ultraviolet light to cure the composition.

5 shows an optical recording / reproducing drive according to the present invention. Referring to FIG. 5, the tray 30 engages the tracks of the housing 20 in such a way that the tray 30 slides in and out of the housing in the direction of arrow A. The tray 30 has a spindle motor 31 and a pickup base 33. The spindle motor 31 has a rotating plate on its axis of rotation. When the optical disk 10 is placed on the rotating plate 32, the spindle motor 31 starts to rotate the optical disk 10. The pickup base 33 slides along the radial direction (indicated by arrow B) of the optical disc 10. An optical pickup device 40 for accessing the recording surface of the optical disc 10 and recording / reproducing information is provided on the pickup base 33.

As is evident from what has been described above, the photocurable adhesive composition according to the present invention meets the requirements of low shrinkage and high adhesion. Therefore, the perfect adhesion to the base is excellent. In addition, the composition according to the present invention does not cause distortion or change in position when used in microelectronic devices such as optical pickups, TFT LCDs, and organic EL devices. Therefore, the sophistication of the process is secured. In addition, when the thixotropic agent is added to the adhesive composition, there is no expansion such as gluten candy. Therefore, a problem may be prevented that an adhesive is applied to an unnecessary portion, thereby degrading the performance of the electronic device.

The invention will be explained in more detail by the examples given for purposes of illustration. For this reason, the scope of the present invention is not limited. Preferred methods for preparing oligourethanes for use in the formulation of UV curable adhesive compositions according to the invention are shown in Examples 1 and 2.

Example  One

Oligodieneurethane methacrylate OUMD Synthesis of -3000H

150 g of liquid oligobutadienediol (Krasol LBH-2000, Kauchuk Co., Czech) was charged into the reactor and stirred while heating to 45-50 ° C. 18.6 g of hexamethylene diisocyanate was added at a rate of 1 g per minute at 55-60 ° C. When the addition was complete, the reaction was stirred at 55-60 ° C. for 4.5-5 hours until the isocyanate group became 2.75% and then cooled to 45-50 ° C. 17.76 g of monomethacrylate propylene glycol in which 0.093 g of dibutyl tin caprylate catalyst was dissolved was added to the reactor at a rate of 1 g per minute. At this time, the temperature should not exceed 50 ~ 55 ℃. The reaction was then stirred for 7-8 hours at 55-60 ° C. until the isocyanate groups were removed. 0.0186 g of p-methoxyphenol was added and stirred for 30 minutes.

The product was a colorless or light yellow viscous material. Dynamic viscosity is 66000 mPa.s.

Example  2

Oligodiene  urethane Methacrylate OUMD Manufacture of -3000T

Synthesis was carried out in the same manner as in Example 1 using 2,4-toluylene diisocyanate as the diisocyanate.

Preparation of UV Curable Compositions Example  3 to 6)

The composition was prepared by thoroughly mixing the ingredients shown in Table 1 in a mixer.

Physical Mechanical Properties of UV Curable Compositions

Tensile strength at 25 ° C. using a tearing machine Instron at the contact of grade CO-120K (Russia) polymethyl methacrylate glass with a sample size of 50 × 50 × 6 mm and cylindrical steel 12 × 18H10T with a diameter of 25 mm. It was determined by testing at a test rate of 20 mm per minute.

I- Strength after 24 hours after adhesion

II- Strength of sample bonded after enduring 72 hours at 60 ° C, 95% humidity

Strength after 20 cycles at III-70 ° C (1 hour) and -30 ° C (1 hour)

Shrinkage was determined by the density ratio of the liquid adhesive and the polymer produced therefrom.

The formulation and properties of the composition are shown in Tables 1 and 2.

Formulation of UV Curable Adhesive Composition  Composition components Content, weight percent Example 3 Example 4 Example 5 Example 6 Invention Comparative example OUMD-3000H 8.1 8.1 8.1 8.1 OUMD-3000T 7.5 7.5 7.5 7.5 Isobonyl methacrylate 15.2 15.2 15.2 15.2 Dicyclopentenyloxyethyl methacrylate 28.4 28.4 28.4 28.4 Trimethacrylate Trimethylolpropane 0.5 0.5 0.5 0.5 Octic methacrylate 1.8 1.8 1.8 1.8 Chloride PVC 4.2 4.2 - 4.2 Oxalic acid 0.7 - 0.7 - Acrylic acid - 1.1 - - Dioctylphthalate 1.8 1.8 1.8 1.8 Aerosil A-175 1.6 1.6 1.6 1.6 BYK-410 0.1 0.1 0.1 0.1 BYK S-740 0.8 0.4 0.8 0.8 Irgacure 184 2.9 2.9 2.9 2.9 Irgacure 651 0.7 0.7 0.7 0.7 Polyethylene 25.7 25.7 29.9 26.4 p-methoxyphenol 0.01 * 0.01 * 0.01 * 0.01 *

0.01 *-parts by weight based on 100 parts by weight of the composition

Properties of UV Curable Adhesive Compositions characteristic Example 3 Example 4 Example 5 Example 6 Shrinkage,% 3.7 3.7 3.7 3.7 Tensile Strength MPa Ⅰ Ⅱ Ⅲ  8.2 3.4 5.0  4.3 1.8 1.7  3.1 0.5-  3.0 0.6- Storage stability, year One 0.5 - -

Table 2 shows that the compositions according to the invention meet the required technical requirements and show superior shrinkage and tensile strength compared to conventional compositions.

Although the present invention has been described by the preferred embodiment, this does not limit the scope of the present invention.

Thus, the composition produced according to the invention meets the required requirements and is also very suitable for use in electronic devices.

Claims (11)

In a photocurable adhesive composition comprising an oligourethane acrylate, a reactive monomer-diluent, a polymer filler, a photopolymerization initiator, an antioxidant, and an adhesion promoter, Adhesion promoters include a mixture of chlorinated polyvinyl chloride and oxalic acid with a chlorine content of 62 to 64% by weight, further comprising a thixotropic agent and a plasticizer, The content of the composition component is 10-30% by weight of oligourethane methacrylate, 32-46% by weight of reactive monomer-diluent, 20-30% by weight of polymer filler, 2.5-5.0% by weight of photoinitiator, 0.005-0.02% by weight of antioxidant %, 3.0-10.0 wt% of polyvinyl chloride, 0.3-2.0 wt% of oxalic acid, 0.5-3.0 wt% of thixotropic agent, 1.0-10.0 wt% of plasticizer. The photocurable adhesive composition of claim 1, wherein the adhesion promoter is a mixture of chlorine content of 62 to 64% by weight of polyvinyl chloride chloride and oxalic acid in a weight ratio of 10: 1 to 5: 1. The photocurable adhesive composition of claim 1, wherein the oligourethane acrylate is a mixture of aliphatic oligobutadiene urethane methacrylate and aromatic oligobutadiene urethane methacrylate in a weight ratio of 1: 1 to 1.5: 1. . The photocurable adhesive composition according to claim 1, wherein the reactive monomer-diluent is a mixture of monofunctional methacrylate having a ring substituent, methacrylate of higher alcohol and polyfunctional methacrylate. The photocurable adhesive composition of claim 1, wherein the polymer filler is high density powder polyethylene having a particle size of 50 µm. An optical pickup apparatus comprising a base and an optical element adhered to the base by using the photocurable composition according to any one of claims 1 to 5. The optical pickup apparatus of claim 6, wherein the optical device comprises a photodiode, a grating, a collimating lens, a beam splitter, a reflecting mirror, a photodetector, a front photodetector, an objective lens, and a base cover. An optical recording / reproducing drive comprising the optical pickup device according to claim 6. The monofunctional methacrylate according to claim 4, wherein the monofunctional methacrylate having a ring substituent is It is isobornyl methacrylate, tetrahydrofurfuryl methacrylate, or dicyclopentenyl oxyethyl methacrylate, The photocurable adhesive composition characterized by the above-mentioned. The method of claim 4, wherein the methacrylate of the higher alcohol, It is an octyl methacrylate, The photocurable adhesive composition characterized by the above-mentioned. The method according to claim 4, The polyfunctional methacrylate, It is triethylene glycol dimethacrylate or trimethylolpropane trimethacrylate, The photocurable adhesive composition characterized by the above-mentioned.

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