KR20160004844A - Adhesives of coating plate for LCD Alignment layer and manufacturing process thereof - Google Patents

Abstract

The present invention relates to an adhesive for a coating plate of an LCD alignment film, and a manufacturing method thereof. The adhesive comprises: an acyl monomer including 100 to 140 parts by weight of 2-ethylhexyl acrylate (2-EHAM), 80 to 120 parts by weight of butyl acrylate (BAM), 80 to 120 parts by weight of ethyl acrylate (EAM), and 20 to 40 parts by weight of lauryl acrylate (LAM); a bridge monomer including 10 to 20 parts by weight of 2,3-epoxypropyl methacrylate (GMA), and 10 to 20 parts by weight of acrylic acid (AAc) or methacrylic acid (mAAc); an initiator including 0.6 to 1.0 parts by weight of (2,2′-azobis(isobutyronitrile), AIBN), and 0.6 to 1.0 parts by weight of benzoyl peroxide (BPO); an acyl copolymer formed by polymerizing a solvent including 130 to 180 parts by weight of ethyl acetate (EAC), 60 to 80 parts by weight of methyl alcohol (MeOH), and 15 to 20 parts by weight of isopropyl alcohol (IPA); and a transparent viscous liquid which is mixed with 400 to 450 parts by weight of ethyl acetate (EAC).

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a pressure-

The present invention relates to a pressure-sensitive adhesive for an LCD (Liquid Crystal Display) alignment film coating plate and a method of manufacturing the same, and more particularly, to a pressure- (Hereinafter referred to as " PET film ") in order to improve durability and strength of a liquid crystal alignment film, and a method for manufacturing the same.

In recent years, as the size of the LCD panel becomes larger, the size of the orientation film printing plate needs to be increased, and the strength of the film is also increased by increasing the size of the printing plate, so that the polyimide (PI) can be continuously printed without any process problems. In addition, dimensional stability, strength, durability, solvent resistance and the like of the printing plate are indispensably required in order to uniformize the printing resolution and the uniform printing of the PI resin and the dimensions of the printed PI resin.

In the process of printing using the PI resin as described above, the PI resin is in the form of a liquid resin ink dissolved in N-methyl-2-pyrolidone (NMP) In order to improve the compatibility and the interfacial adhesion of the PI resin to the uniformity of the PI resin during the application to the disk, the alignment film printing plate is first immersed sufficiently in the NMP solvent to increase the activity of the surface. In such an NMP solvent atmosphere, the alignment film printing plate is required to have solvent resistance to NMP. Especially, in the case of a large-sized LCD panel, as the size of the printing plate increases accordingly, the backing of the printing plate is used for the backside adhesion to the PET film excellent in solvent resistance and dimensional stability. There are problems such as swelling, transfer, contamination and dissolution of the pressure-sensitive adhesive due to the constituent components and physicochemical properties of the pressure-sensitive adhesive.

In the prior art, an epoxy resin and a silicone resin having excellent physical properties are used alone or in combination with consideration of solvent resistance and chemical resistance. However, since a large-size LCD panel is required to be formed by attaching a plurality of printing plates to a large-size LCD panel, it is difficult to remove the original plate in a correction process such as removing a part of the printing plate and reattaching the printing plate. .

However, a butadiene-based pressure-sensitive adhesive improved in adhesive properties has been developed, but its use is extremely limited due to some swelling phenomenon due to penetration of NMP solvent. In addition, when the foreign matter enters between the printing plate and the PET film during the printing plate manufacturing process, the printing plate is peeled off in order to reuse the expensive printing plate. In this case, the pressure- Is a phenomenon of leakage of adhesive.

As a prior art related to the present invention, Korean Patent Registration No. 10-0957618 (Published on May 05, 2010) discloses a photoreceptor having a photosensitive resin layer on which a coating pattern is formed, a PET film layer formed on the back surface of the photosensitive resin, And a non-slip layer comprising at least one of a urethane resin, an acrylic resin, a silicone resin and an emulsion resin so as to prevent slip on the PET film layer.

Meanwhile, in the present invention, as a result of repeated studies on a polyacrylic pressure-sensitive adhesive polymerized by applying an acrylic monomer having superior compatibility with a PET film and excellent compatibility with an NMP solvent while overcoming the conventional technical problems, Polyacrylic polymeric pressure-sensitive adhesives can be polymerized by mixing various monomers to give various properties such as glass transition temperature (Tg), broad molecular weight distribution and crosslinking degree, and easy polymerization control. And by applying various functional acrylic monomers to adjust the secondary characteristics such as crosslinking and curing, LG Chemical has developed a pressure-sensitive adhesive for an LCD alignment film coating plate excellent in solvent resistance and adhesive strength in the process of laminating an LCD alignment film printing plate and a PET film Thereby completing the present invention.

Korean Registered Patent No. 10-0957618 (Notification Date: May 05, 2010)

It is an object of the present invention to provide a process for preparing an acrylic composition having excellent cohesive force and adhesive force which are not possessed by existing pressure sensitive adhesives and having excellent solvent resistance, The crosslinking density due to addition of a molecular weight, a low molecular weight component or a weight loss of a crosslinking agent is lowered so that a stress caused by a dimensional change of the pressure-sensitive adhesive with respect to a solvent is alleviated in the pressure-sensitive adhesive itself, and a monomer acting as a crosslinking reaction point An adhesive for an LCD alignment film coating plate capable of enhancing crosslinking efficiency and introducing a polar group such as a carboxyl group or a hydroxyl group at the tip of a relatively long ester group and balancing durability as well as stress relaxation and reworkability, .

The pressure sensitive adhesive for an LCD alignment film coating plate according to the present invention may comprise 100 to 140 parts by weight of 2-ethylhexyl acrylate (2-EHAM), 80 to 120 parts by weight of butyl acrylate (BAM) Acryl monomer consisting of 80 to 120 parts by weight of ethyl acrylate (EAM) and 20 to 40 parts by weight of lauryl acrylate (LAM); 10-20 parts by weight of 2,3-epoxypropyl methacrylate (GMA), 10-20 parts by weight of acrylic acid (AAc) or methacrylic acid (mAAc) Monomers; 0.6 to 1.0 part by weight of 2,2'-azobis (isobutyronitrile), AIBN, and 0.6 to 1.0 part by weight of benzoyl peroxide (BPO); A solvent composed of 130 to 180 parts by weight of ethyl acetate (EAC), 60 to 80 parts by weight of methanol (MeOH) and 15 to 20 parts by weight of isopropyl alcohol (IPA) A copolymer and a transparent mucilage mixed with 400 to 450 parts by weight of ethyl acetate (EAC), wherein the acrylic copolymer has a solid content of 30 to 40% by weight (at 150 DEG C for 30 minutes) 2,000 to 3,000 cps (25 DEG C).

The method for producing an adhesive for an LCD alignment film coating plate of the present invention comprises a first step of adding and mixing the acrylic monomer, the crosslinking monomer, an initiator and a solvent into a reactor equipped with a reflux condenser; When paddle type reactor agitator is stirred at a speed of 20 to 30 rpm and steam is supplied to raise the temperature of the reactor, reflux is started at the boiling point of the solvent and monomer and the reaction is initiated. At this time, the inner temperature of the reactor is maintained at 68 to 72 ° C A second step of obtaining an acrylic copolymer by carrying out a polymerization reaction; The outer temperature of the reactor was fixed at 80 ° C in consideration of the half life of the initiator, and the inner temperature of the reactor was reacted and aged at a temperature of 68 to 72 ° C for 6 hours. Then, ethyl acetate (EAC) And a third step of mixing and cooling the mixture to obtain a transparent slime.

The pressure sensitive adhesive for an LCD alignment film coating plate produced by the manufacturing method of the present invention has excellent cohesive force and adhesiveness and is excellent in solvent resistance. The pressure sensitive adhesive itself alleviates the stress caused by the dimensional change with respect to the solvent of the pressure sensitive adhesive, The present invention can reduce the normal cost of display manufacturing due to the recycling of the printing plate and the reduction of the defective ratio, thereby contributing greatly to the material companies suffering from the decrease in the display unit price It is effective.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a configuration diagram showing a state in which an alignment film printing plate is joined to a PET adhesive film. Fig.
2 is a photograph showing the surface swelling phenomenon in the NMP solvent resistance comparative experiment.

The pressure sensitive adhesive for an LCD alignment film coating plate according to the present invention is prepared by adding 100 to 140 parts by weight of 2-ethylhexyl acrylate (2-EHAM), butyl acrylate (BAM) 80 To 120 parts by weight of acrylic acid, 80 to 120 parts by weight of ethyl acrylate (EAM), and 20 to 40 parts by weight of lauryl acrylate (LAM); 10-20 parts by weight of 2,3-epoxypropyl methacrylate (GMA), 10-20 parts by weight of acrylic acid (AAc) or methacrylic acid (mAAc) Monomers; 0.6 to 1.0 part by weight of 2,2'-azobis (isobutyronitrile), AIBN, and 0.6 to 1.0 part by weight of benzoyl peroxide (BPO); A solvent composed of 130 to 180 parts by weight of ethyl acetate (EAC), 60 to 80 parts by weight of methanol (MeOH) and 15 to 20 parts by weight of isopropyl alcohol (IPA) A first step of mixing; When paddle type reactor agitator is stirred at a speed of 20 to 30 rpm and steam is supplied to raise the temperature of the reactor, reflux is started at the boiling point of the solvent and monomer and the reaction is initiated. At this time, the inner temperature of the reactor is maintained at 68 to 72 ° C A second step of obtaining an acrylic copolymer by carrying out a polymerization reaction; The outer temperature of the reactor was fixed at 80 ° C in consideration of the half life of the initiator, and the inner temperature of the reactor was reacted and aged at a temperature of 68 to 72 ° C for 6 hours. Then, ethyl acetate (EAC) And a third step of mixing and cooling the mixture to obtain a transparent slime.

Hereinafter, the process of each step of the present invention will be described in detail. However, it is to be understood that the present invention is not limited to the technical idea of the present invention, And does not mean that the category is limited.

First, in a first step, a reactor equipped with a reflux condenser is charged with 100 to 140 parts by weight of 2-ethylhexyl acrylate (2-EHAM), 80 to 120 parts by weight of butyl acrylate (BAM) Acryl monomer consisting of 80 to 120 parts by weight of ethyl acrylate (EAM) and 20 to 40 parts by weight of lauryl acrylate (LAM); 10-20 parts by weight of 2,3-epoxypropyl methacrylate (GMA), 10-20 parts by weight of acrylic acid (AAc) or methacrylic acid (mAAc) Monomers; 0.6 to 1.0 part by weight of 2,2'-azobis (isobutyronitrile), AIBN, and 0.6 to 1.0 part by weight of benzoyl peroxide (BPO); A solvent composed of 130 to 180 parts by weight of ethyl acetate (EAC), 60 to 80 parts by weight of methanol (MeOH) and 15 to 20 parts by weight of isopropyl alcohol (IPA) Mixing process.

In the second step, the paddle-shaped reactor stirrer is stirred at a speed of 20 to 30 rpm. When the temperature of the reactor is raised by supplying steam, the reflux starts at the boiling point of the solvent and the monomer, and the reaction is initiated. To 72 ° C to obtain an acrylic copolymer.

Generally, the acrylic pressure-sensitive adhesive is obtained by using a monomer having a low glass transition temperature (Tg) such as butyl acrylate or 2-ethylhexyl acrylate to give cohesive force or adhesiveness, and (meth) acrylic acid or And acrylic polymers polymerized by appropriately combining monomers having a relatively high Tg, such as 2-hydroxyethyl methacrylate, and the like, as main components. The cohesive force can be controlled by blending a polyfunctional isocyanate or an epoxy compound as a curing agent. In order to increase the cohesive force, methods have been taken to increase the cohesive force-imparting component, to increase the molecular weight of the polymer, to remove the low molecular weight component, and to increase the crosslinking efficiency using the crosslinking agent. In order to increase the adhesive strength, Or a silane coupling agent or the like is added thereto. However, it is difficult to obtain a pressure-sensitive adhesive satisfying both cohesive strength and adhesive strength.

However, the pressure sensitive adhesive for an LCD alignment film printing plate coating plate of the present invention contains an acrylic acid copolymer in an amount of about 30 to 40 parts by weight based on 100 parts by weight of the whole, and the acrylic acid copolymer is a solution type resin containing an acrylic monomer, And is in the range of 40 占 폚 to -30 占 폚. As the organic tackifier, an appropriate solvent resistance can be obtained.

That is, in the present invention, the lowering of the cohesive force-imparting component of the acrylic polymer, the change of the main polymer (lowering the Tg), the lowering of the molecular weight of the polymer, the addition of the lower molecular weight component or the reduction of the crosslinking agent, The stress caused by the dimensional change is to be relieved by the adhesive itself. Further, when a polar group such as a carboxyl group or a hydroxyl group is introduced at the end of a relatively long ester group such as lauryl acrylate as a monomer which imparts adhesiveness or functions as a cross-linking reaction point, the crosslinking efficiency becomes high and the stress relaxation property and rework performance A pressure-sensitive adhesive which can balance the durability together can be produced.

In the present invention, the acrylic monomer for imparting tackiness is selected from the group consisting of 2-ethylhexyl acrylate (2-EHAM), butyl acrylate (BAM), ethyl acrylate (EAM) 80 to 120 parts by weight and 20 to 40 parts by weight of lauryl acrylate (LAM) and the like were used in the range of 100 to 140 parts by weight, 2,3-epoxy 10 to 20 parts by weight of each of 2,3-epoxypropyl methacrylate (GMA), acrylic acid (AAc) or methacrylic acid (mAAc) were used.

Initiators were prepared by mixing 0.6-1.0 parts by weight of 2,2-azobis (isobutyronitrile), AIBN, and benzoyl peroxide (BPO) The composition is composed of 130 to 180 parts by weight, 60 to 80 parts by weight and 15 to 20 parts by weight of ethyl acetate (EAC), methanol (MeOH) and isopropyl alcohol (IPA) Solvent was used.

Finally, in the third step, the outer temperature of the reactor was fixed at 80 ° C in consideration of the half life of the initiator, and the inner temperature of the reactor was reacted and aged at 68 to 72 ° C for 6 hours. Ethyl acetate , And 400 to 450 parts by weight of EAC are mixed and cooled to obtain a transparent mucus. The transparent mucilage has a solid content of 30 to 40% by weight (dry at 150 ° C for 30 minutes) and a viscosity of about 2,000 to 3,000 cps 25 < 0 > C).

Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples of the method for producing the pressure sensitive adhesive for an LCD alignment film coating plate. However, the present invention is not limited thereto The present invention will be described by way of preferred embodiments.

[Example 1]

120 parts by weight of main monomer 2-EHAM, 100 parts by weight of BAM, 30 parts by weight of LAM, 10 parts by weight of GMA and 10 parts by weight of AAc were added to a 2 L five-necked flask equipped with a reflux condenser, 150 parts by weight of EAC as a solvent, 70 parts by weight of MeOH, 15 parts by weight of IPA and 0.8 parts by weight of BPO and AIBN as initiators were added, and the stirrer was fixed at 20 rpm. Lt; RTI ID = 0.0 > 72 C. < / RTI > The reflux then begins and the internal temperature is maintained at 68-72 ° C, and the chain reaction proceeds. The total reaction time was 6 hours. After completion of the reaction, 413.4 parts by weight of the solvent EAC was added to the reactor, and the reaction was terminated by stirring until completely cooled. The acrylic copolymer thus prepared is separately prepared.

[Comparative Example 1] - [Comparative Example 3]

The synthesis was carried out in the same manner as in Example 1 except that the ratio of the solvent to be added was varied. In the conventional solution polymerization method, the amount of the catalyst is fixed to 0.5% of the amount of the monomer and the addition or the addition of the catalyst affects the yield of the reaction. The composition of the solvent has an important influence on the pressure-sensitive adhesive composition. Particularly, when the crosslinking monomer and the functional monomer are introduced, the injection ratio and composition of the solvent have a more significant influence. Thus, the composition of the solvent was varied in the composition shown in Table 1 below.

division Ingredients Example 1 Comparative Example 1 Comparative Example 2 Comparative Example 3 Main monomer 2-EHAM 120 120 120 120 BAM 100 100 100 100 EAM 80 80 80 80 LAM 30 30 30 20 Crosslinking monomer GMA 10 10 - 10 2-HEMA - - 10 - AAc 10 10 10 20 Initiator AIBN 0.8 0.8 0.8 0.8 BPO 0.8 0.8 0.8 0.8 solvent EAC 150 230 150 150 MeOH 70 - 75 55 IPA 15 - 10 30 Additive solvent EAC 413.4 413.4 413.4 413.4

In the case of Comparative Example 1, it was observed that the crosslinking reaction of the polymer resin proceeded as the reaction proceeded. After 2 hours of reaction, the resins in the reactor were completely entangled and gelated, and the synthesis did not progress any more. In the case of Comparative Example 2, the initial boiling temperature was also good, but after 4 hours of reaction, the contents were completely gelled and the reaction could not proceed further. In Comparative Example 3, the viscosity of the polymer resin was observed to be too low even after the reaction was completely terminated, and the flowability was such that coating was impossible. Therefore, the amount of IPA added in the solvent composition is considered to be a very important parameter. IPA is considered to function as a chain transfer agent in the polymerization process. In the present invention, the composition of Example 1 using 15 parts by weight of IPA It was confirmed to be most appropriate.

[Example 2] - [Example 3], [Comparative Example 4] - [Comparative Example 5]

The synthesis was carried out by varying the compositions of the functional crosslinking monomers in the synthesis of Example 1. Functional crosslinking monomers were prepared by varying the amounts of 2-HEMA, GMA, AAC, and the like as shown in Table 2 below.

division Ingredients Example 2 Example 3 Comparative Example 4 Comparative Example 5 Main monomer 2-EHAM 120 120 120 120 BAM 100 100 100 100 EAM 80 80 80 80 LAM 20 20 30 20 Crosslinking monomer GMA 20 10 - 30 2-HEMA - - 10 - AAc 10 20 10 - Initiator AIBN 0.8 0.8 0.8 0.8 BPO 0.8 0.8 0.8 0.8 solvent EAC 150 150 150 150 MeOH 70 70 70 70 IPA 15 15 15 15 Additive solvent EAC 413.4 413.4 413.4 413.4

[Experimental Example]

In order to evaluate the physical properties of the acryl pressure-sensitive adhesive synthesized as described above, experiments were conducted to confirm coating and adhesion properties on the PET film. 0.5 part by weight of a silane coupling agent and 0.5 part by weight of a crosslinking agent TDI were mixed with 100 parts by weight of the acryl pressure-sensitive adhesive and homogeneously mixed for 30 minutes, followed by applying a comma coating of 30 microns (占 퐉). Drying conditions were 130 ~ 150 ℃ for 30 sec, and aging was carried out in a constant temperature chamber at 40 ~ 50 ℃ for 48 hours. The adhesive strength of each resin was measured by the ASTM D1000 method, and the initial adhesive strength was tested according to ASTM D3121. In addition to strength properties as a pressure-sensitive adhesive, solvent resistance to NMP is an important part of the present invention. Therefore, the degree of swelling of the pressure-sensitive adhesive was evaluated by evaluating the NMP solvent resistance after the adhesion. The swelling and the solubility of the resin in the solvent were evaluated by first immersing in NMP as a solvent for 24 hours, washing in water and further ultrasonic cleaning for 30 minutes To confirm the change of the completely dried surface. The results are shown in Table 3 below.

division Example 1 Example 2 Example 3 Comparative Example 4 Comparative Example 5 Acrylic pressure-sensitive adhesive (parts by weight) 100 100 100 100 100 Silane coupling agent (parts by weight), MAPMS 0.5 0.5 0.5 0.5 0.5 Crosslinking agent (parts by weight), TDI 0.5 0.5 0.5 0.5 0.5 Adhesion (g / cm2) 1060 1190 1210 950 750 Initial adhesion (No.) 9 9 9 10 8 Solvent resistance (NMP), swelling degree (mm) 0.5 1.0 1.0 2.5 (week)

(Note): No evaluation of the solvent resistance due to the adhesive strength specification

From the results shown in the above Table 3, it can be judged that the AAc content significantly affects the adhesive property in the case of the acrylic adhesive. It can be seen that the acrylic pressure-sensitive adhesive which is generally applicable as a pressure-sensitive adhesive is useful as a pressure-sensitive adhesive in all the test compositions except for Comparative Example 5 since an adhesive force of 1,000 g / cm 2 or more is required. However, in the case of the solvent resistance, there is much variation in the content and type of the functional monomer. As shown in Comparative Example 4, 2-HEMA has lower solvent resistance than GMA, and even if AAc content is increased, I did. Therefore, considering the solvent resistance, the adhesive strength and the adhesive strength, the ratio of the functional monomer serves as an important variable, and the composition of Examples 1 to 3 is the most suitable composition in which the degree of swelling is less than 1 mm in the present solvent resistance standard Respectively.

As described above, the pressure sensitive adhesive for an LCD alignment film coating plate of the present invention can be variously substituted, modified and changed within the scope of the technical idea of the present invention. As a technology that can be manufactured, it can be used in a variety of uses and forms, and thus it is very likely to be used in related industries.

Claims (3)

100 to 140 parts by weight of 2-ethylhexyl acrylate (2-EHAM), 80 to 120 parts by weight of butyl acrylate (BAM), 80 to 120 parts by weight of ethyl acrylate (EAM) An acrylic monomer composed of 20 to 40 parts by weight of lauryl acrylate (LAM); 10-20 parts by weight of 2,3-epoxypropyl methacrylate (GMA), 10-20 parts by weight of acrylic acid (AAc) or methacrylic acid (mAAc) Monomers; 0.6 to 1.0 part by weight of 2,2'-azobis (isobutyronitrile), AIBN, and 0.6 to 1.0 part by weight of benzoyl peroxide (BPO); A solvent composed of 130 to 180 parts by weight of ethyl acetate (EAC), 60 to 80 parts by weight of methanol (MeOH) and 15 to 20 parts by weight of isopropyl alcohol (IPA) Copolymer, and
Wherein the adhesive layer comprises a transparent mucilagent mixed with 400 to 450 parts by weight of ethyl acetate (EAC).
The method according to claim 1,
Wherein the acrylic copolymer has a solid content of 30 to 40% by weight (at 150 캜 for 30 minutes) and a viscosity of 2,000 to 3,000 cps at 25 캜.
100 to 140 parts by weight of 2-ethylhexyl acrylate (2-EHAM), 80 to 120 parts by weight of butyl acrylate (BAM), 80 parts by weight of ethyl acrylate, 80 to 120 parts by weight of EAM) and 20 to 40 parts by weight of lauryl acrylate (LAM); 10-20 parts by weight of 2,3-epoxypropyl methacrylate (GMA), 10-20 parts by weight of acrylic acid (AAc) or methacrylic acid (mAAc) Monomers; 0.6 to 1.0 part by weight of 2,2'-azobis (isobutyronitrile), AIBN, and 0.6 to 1.0 part by weight of benzoyl peroxide (BPO); A solvent composed of 130 to 180 parts by weight of ethyl acetate (EAC), 60 to 80 parts by weight of methanol (MeOH) and 15 to 20 parts by weight of isopropyl alcohol (IPA) A first step of mixing;
When paddle type reactor agitator is stirred at a speed of 20 to 30 rpm and steam is supplied to raise the temperature of the reactor, reflux is started at the boiling point of the solvent and monomer and the reaction is initiated. At this time, the inner temperature of the reactor is maintained at 68 to 72 ° C A second step of obtaining an acrylic copolymer by carrying out a polymerization reaction;
The outer temperature of the reactor was fixed at 80 ° C in consideration of the half life of the initiator, and the inner temperature of the reactor was reacted and aged at a temperature of 68 to 72 ° C for 6 hours. Then, ethyl acetate (EAC) A third step of mixing and cooling the mixture to obtain a transparent slime;
Wherein the pressure-sensitive adhesive layer is formed on the surface of the pressure-sensitive adhesive layer.

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