KR20050105668A - Preparation of uv curable agent by suspension polymerization - Google Patents

Abstract

The present invention relates to a method of preparing a binder polymer bead for UV curing through suspension polymerization by introducing a crude liquid consisting of ion-exchanged water, a monomer, a crosslinking agent, a fat-soluble initiator and a stabilizer in a reactor, wherein the crude liquid is homogenized prior to suspension polymerization. By going through the step further, it is possible to secure stability even if only a small amount of stabilizer is used in an amount of 0.1 to 3% by weight (based on the total solid content), and as a result, the productivity and resolution of the dry film resist including the same can be improved. Provided is a method of preparing binder polymer beads for UV curing.

Description

Preparation method of binder polymer beads for heat curing through suspension polymerization {Preparation of UV curable agent by Suspension Polymerization}

The present invention relates to a method for preparing UV curable binder polymer beads (Polymer Beads) through suspension polymerization.

The process of manufacturing a printed circuit board (PCB) circuit using a photosensitive film, that is, a dry film, is introduced in Korean Patent No. 271216.

The photosensitive resin composition which comprises the photosensitive layer of a dry film photoresist contains a binder polymer, a photopolymerization monomer, a photoinitiator, and other additives.

In general, the binder polymer beads in the photosensitive resin composition are charged with ion exchanged water, monomers, crosslinking agents, fat soluble initiators and stabilizers in a reactor, stirred at high speed, and heated to an internal temperature of 50 to 80 ° C., followed by reaction for 8 to 24 hours. The temperature is lowered to obtain spherical binder polymer particles.

In this case, when a binder polymer is prepared through suspension polymerization by simply mixing an aqueous system and a monomer system, a small amount of insoluble components that are not easily dissolved in a solvent is present, thereby preventing the resolution of the dry film. In general, since the optical properties of the material greatly affect the resolution, when the dry film is made, the photosensitive resin composition crude solution is passed through a network of several μm to remove impurities that may cause light scattering.

Therefore, when a large amount of stabilizer is used, there is a problem that exists as an insoluble component and consequently causes light scattering.

Accordingly, the present inventors have been trying to easily solve the problem of excessive use of a stabilizer in preparing the binder polymer beads for the photosensitive resin through suspension polymerization, and then, after polymerization, the crude liquid is transferred from the homogenizer before suspension polymerization. As a result, it was found that stability can be ensured even with a small amount of stabilizer, thereby improving the resolution while improving the productivity of the dry film resist, thereby completing the present invention.

Accordingly, it is an object of the present invention to provide a method for producing a binder polymer for UV curing that can improve the productivity and resolution of a dry film resistor by producing a binder polymer for curing UV using a homogenizer.

In order to achieve the above object, a method for preparing a binder polymer for UV curing is to add a crude liquid consisting of ion-exchanged water, monomers, crosslinking agents, fat-soluble initiators and stabilizers into a reactor to undergo suspension polymerization, and to prepare the crude liquid before suspension polymerization. After passing through the homogenizer and passing through it, the stabilizer is characterized by using 0.1 to 3% by weight based on the total solids content.

The present invention will be described in more detail as follows.

The present invention relates to a manufacturing method for reducing the stabilizer content in the polymer beads by reducing the amount of stabilizer by transferring the crude liquid to the homogenizer prior to the polymerization in the manufacture of the UV curing binder polymer through a suspension polymerization process.

In the suspension polymerization process of the binder polymer for UV curing, ion-exchanged water, monomers, crosslinking agents, fat-soluble initiators and stabilizers are added to the reactor, stirred at high speed, and the internal temperature is raised to 50-80 ° C., followed by 8 to 24 hours of reaction. The temperature is lowered to room temperature to obtain spherical binder polymer particles.

The binder polymer is a linear acrylic acid polymer, which is a copolymerized acrylic acid polymer obtained through copolymerization of two or more monomers. The monomers include methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, acrylic acid, methacrylic acid, 2-hydroxyethyl acrylate, 2-hydroxyethyl Methacrylate, 2-hydroxychrome acrylate, 2-hydroxypropyl methacrylate, acrylamide, methacrylamide, styrene, α-methyl styrene, cyclohexyl acrylate and the like.

Stabilizers are typically polyvinylalcohol, polyvinylpyrrolidone, methyl cellulose, ethyl cellulose, sodium carboxymethyl cellulose, polyacrylic acid, polymethacrylic acid, sodium polyacrylate, sodium polymethacrylate, gelatin, polyacrylamide and Polyethylene oxide and the like are used, and the content thereof is preferably 0.1 to 3.0% by weight based on the total polymer beads. When not passed through the homogenizer according to the present invention, the stabilizer must be used in excess to obtain the desired effect.

As the initiator, benzoyl peroxide, azobisisobutyronitrile, azobismethylbutyronitrile, azobiscyclohexanecarbonitrile and the like are used.

Ion-exchanged water used in the production of polymer beads is pure water having a resistance value of 5 mega ohms or more (5 MΩ) or more under a nitrogen stream generated through an ion exchanger, and is used at 150 to 400 wt% based on the total monomers.

After mixing the monomer system and the water system as described above, the mixture is stirred at several hundred rpm for 30 minutes and then transferred to the homogenizer. It is preferable that the working pressure of a homogenizer is 1000-5000psi. The reaction temperature and the reaction time are obtained at 50 to 80 DEG C and 8 to 24 hours, respectively.

After completion of the reaction, the polymer bead solution is washed repeatedly with a filter and ion-exchanged water, followed by vacuum drying at 60 ° C. for 24 hours to obtain a final product.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. However, the following examples are provided to more easily understand the present invention, but the present invention is not limited to these examples.

Examples 1-2 and Comparative Examples

As shown in Table 1, BP 1, 2, and 3 were obtained by changing the content of the stabilizer with the same monomer composition. Its physical properties are shown in Table 1.

(Unit: parts by weight) Comparative Example (BP 1) Example 1 (BP 2) Example 2 (BP 3) Monomer composition Methyl methacrylate 105 105 105 Styrene 60 60 60 Ethyl acrylate 66 66 66 Butyl acrylate 10 10 10 Methacrylic acid 60 60 60 Stabilizer PVA (10%) 30 10 8  Ion exchange water 740 740 740 Weight average molecular weight 77,486 75,897 76,892 Molecular weight distribution 2.54 2.50 2.49 Acid 130.5 130 131 Glass transition temperature (℃) 108 108 107 Average particle size (㎛) 100 10 12

Comparative Example (BP 1) was prepared by preparing a solution with the composition as shown in Table 1, and added to a 2L reactor and heated at an internal temperature of 60 ℃ while stirring at 250 rpm speed under a nitrogen stream, and then reacted at 60 ℃ for 8 hours , Examples 1 to 2 (BP 2, BP 3) is prepared by a suspension polymerization method such as BP 1 and then transferred to a homogenizer (pressure 1000 ~ 5000psi) twice before polymerization.

In the case of BP 1, it is easy to see that the transparency is lower than that of BP 2 and 3 when melted in MEK. In the case of BP2 and 3 using a homogenizer, stability can be ensured even with a small amount of stabilizer, and the average size of the prepared particles is about 10 to 12 μm. Both polymers were prepared by vacuum drying at 60 ° C. for 24 hours.

In case of acid value or glass transition temperature, it can be seen that BP 1, 2 and 3 are similar. In the case of molecular weight distribution and particle size, it was confirmed that BP 1 is larger than BP 2 and BP 3.

Experimental Example

The binder polymers prepared in Examples and Comparative Examples were manufactured with a dry film photoresist having a composition as shown in Table 2, and then a circuit was constructed according to a general PCB manufacturing process to evaluate physical properties of the dry film resist.

Specifically, the composition prepared as shown in Table 2 is uniformly coated on polyethylene terephthalate and dried to prepare a dry film photoresist. After developing process in PCB circuit process, dry film sensitivity, resolution and session adhesion were evaluated.

Table 3 shows the results of evaluating the physical properties of the dry film photoresist by varying the exposure dose (however, a crude liquid was prepared using the composition of Table 2 and no separate filtration process was performed).

Polymer binder  Binder polymer 50 Photoinitiator Benzophenone 2.0 4,4 '-(bisdidecylamino) benzophenone 1.0 Luco Crystal Violet 3.0 Toluene Sulphonic Acid Monohydrate 0.5 Diamond Green GH 0.5 Photopolymerizable monomer 9G 10.0 APG-400 10.0 BPE-500 10..0  menstruum Methyl ethyl ketone 13.0 Luco Crystal Violet (4,4'-tris (dimethylamino) triphenylmethane): Diamond Green GH from Hodogaya Chemical Co., Ltd: HG from Hodogaya Chemical Co., Ltd.9G (polyethylene glycol # 400 diacrylate): Shinnakamura APG-400 (Polypropylene glycol # 400 diacrylate) manufactured by Chemicals, Inc .: BPE-500 (2-2, bis [4- (methacryloxy polyethoxy) phenyl] propane: Shinnakamura Chemicals, Inc. product

Exposure amount (mJ / ㎠) Binder polymer BP 1 BP 2 BP 3 Sensitivity 25 5.0 5.0 5.0 35 6.0 6.0 6.0 45 7.5 7.0 6.9 Resolution (μm) (Line / Space = 1/1) 25 40 50 49 35 50 56 56 45 61 63 63 35 35  Fine wire adhesion (㎛) 25 35 33 30 35 30 27 26 45 25 The film thickness is 30 μm. The minimum development time is 22 seconds. -Sensitivity was evaluated using Stouffer 21-stage step tablet-Condition during development: Na ₂ CO ₃ concentration 1wt%, 30 ℃, spray pressure 1.5kg / ㎠ · sec Break Point 50%

From the results of Table 3, it can be seen that when the binder polymers BP 2 and BP 3 obtained through the polymerization method using a homogenizer shows a higher resolution than when using the binder polymer BP 1 which is not .

As described in detail above, when the homogenizer is passed through the binder polymer beads according to the present invention, the amount of stabilizer can be reduced, so that light scattering due to impurities can be reduced. Can improve.

Claims (2)

In a method of preparing a binder polymer beads for UV curing through suspension polymerization by introducing a crude liquid consisting of ion-exchanged water, a monomer, a crosslinking agent, a fat-soluble initiator and a stabilizer to the reactor, Passing the crude liquid through a homogenizer prior to suspension polymerization, and using a stabilizer of 0.1 to 3% by weight based on the total solids content, UV curing binder polymer beads production method. The method of claim 1, wherein the homogenizer is used at a pressure of 1000 to 5000 psi.