TW201422743A - Adhesive composition for liquid crystal display and method of making and using the same - Google Patents

Abstract

One embodiment of this invention provides an adhesive composition for a liquid crystal display comprising the adhesive resin and the black pigment coated on a part of area of the bottom surface of the liquid crystal panel of the liquid crystal display or on a part of area of the backlight module, so as to bond the liquid crystal panel and the backlight module. The adhesive composition for a liquid crystal display of this invention is to firmly bond the liquid crystal panel and the backlight module so as to reduce the weight and thickness of the liquid crystal display thus made. In addition, the adhesive composition contains the black pigment dispersed therein to block the light permeated from the backlight module to the exterior of the liquid crystal display module to thereby increase the performance of the liquid crystal. The present invention uses a simple coating process without having to employ other processes after coating so as to reduce costs.

Description

Adhesive composition for liquid crystal display and method of making and using same

The present application claims priority to and the benefit of the benefit of the benefit of the benefit of the benefit of the benefit of the benefit of the benefit of the benefit of the benefit of the benefit of the benefit of the benefit.

This invention relates to an adhesive composition, and more particularly to a manufacturing technique for an adhesive composition that can be used in the manufacture of liquid crystal displays.

Today, thin, lightweight, and low-cost strategy has become a feature of Flat Panel Display. Among them, liquid crystal display devices are widely used in notebook computers, NetBooks and TVs due to their excellent resolution, color display and image quality.

The liquid crystal display is a liquid crystal panel in which a liquid crystal layer is interposed between two substrates arranged side by side as a required member, and the alignment direction of the liquid crystal molecules is changed to an electric field in the liquid crystal panel to realize a difference in transmittance. However, since the liquid crystal panel does not have its own light-emitting element, it is necessary to display another light source by image to differ in transmittance. To this end, a backlight unit in which a light source is mounted is mounted on the surface of the liquid crystal panel.

Conventionally, for the liquid crystal panel and the backlight module, a process of assembling using a top cover is employed. However, in addition to the problems of thinning and light weight of liquid crystal displays currently required, the top cover also causes an unnecessary increase in process cost. Therefore, the manufacture of a liquid crystal display that does not require a top cover has begun. The liquid crystal display is provided with a side cover that forms a panel side support device for supporting a side surface of the liquid crystal panel. However, when the liquid crystal panel is assembled, the liquid crystal panel needs to be bent, but the liquid crystal panel is broken or the vertex is partially broken due to the bending pressure of the liquid crystal panel. problem.

In order to solve the problem, the edge of the backlight module or the edge of the liquid crystal panel has begun to be joined by tape. However, when the tape is used, the release paper of the tape is stuck on the front side of the tape, and the release paper is formed in front of the bonding portion, so that the air between the optical sheets cannot be discharged. Therefore, when the vacuum chamber is placed in the panel, the backlight module is easily broken. Moreover, the attachment portion of the tape is likely to be attached with the attachment at the time of uncovering. Moreover, the space from which the light emitted from the backlight module is smeared by the tape is oozing out to the outside to reduce the efficiency of the liquid crystal panel.

In order to solve the above problems, the present invention provides an adhesive composition for a liquid crystal display, which is used for attaching a liquid crystal panel and a backlight module, and further has a light blocking function for blocking light oozing out from the backlight module. To the outside.

In order to solve the above problems, the present invention further provides an adhesive composition for a liquid crystal display which is simple in a coating process and which does not require further processes after application.

The adhesive composition for a liquid crystal display according to an embodiment of the present invention comprises 10 to 30 parts by weight of a black pigment contained in 100 parts by weight of the binder resin, and is applied to a portion of the area under the liquid crystal panel of the liquid crystal display or a portion of the backlight module. And bonding the liquid crystal panel and the backlight module.

In one embodiment of the invention, the above binder resin is a two-component polyurethane resin.

The adhesive composition for liquid crystal display according to another embodiment of the present invention comprises 10 to 30 parts by weight of a black pigment, 10 to 30 parts by weight of an elastic resin, and 1 to 10 parts by weight of a hardening agent in 100 parts by weight of the binder resin; The liquid crystal panel and the backlight module are bonded to a portion of the area under the liquid crystal panel of the liquid crystal display or a portion of the backlight module.

In one embodiment of the invention, the black pigment is oxidized from carbon black At least one black pigment selected from the group consisting of iron, carbon nanotubes and graphite has an average particle diameter of 13 to 70 nm.

In one embodiment of the present invention, the above adhesive composition further comprises 0.05 to 20 parts by weight of the inorganic filler selected from at least one selected from the group consisting of ceria, alumina, clay or talc.

In one embodiment of the present invention, the above elastic resin has a viscosity of 25,000 to 30,000 cPs at a temperature of 45 ° C and a molecular weight of 5,500 to 6,000 g/mol.

A method for producing an adhesive composition for a liquid crystal display according to another embodiment of the present invention is characterized in that the method comprises the steps of: preparing a first mixture comprising an isocyanate compound; preparing a first comprising a polyhydroxy compound, a black pigment, an elastic resin and a hardening accelerator a second mixture; and placing the first mixture and the second mixture into a two-component syringe.

In one embodiment of the invention, the volume ratio of the first mixture to the second mixture is from 50:40 to 50:60.

In one embodiment of the invention, the above adhesive composition further comprises: pressurizing the first mixture and the second mixture introduced in the two-component syringe, at the end of the two-component syringe a step of discharging the mixture formed on the outlet and discharging it from the discharge port

In the pressure-sensitive adhesive composition for a liquid crystal display of the present invention, the liquid crystal panel and the backlight module are firmly bonded together, and the manufactured liquid crystal display is made lighter and thinner. Moreover, a black pigment is dispersed in the adhesive composition to block the light emitted from the backlight module from oozing out to the outside of the liquid crystal display module, thereby improving the efficiency of the liquid crystal panel.

In addition, the coating process is simple, and no additional process is required after coating to save costs.

The above described features and advantages of the invention will be apparent from the following description.

The adhesive composition for liquid crystal displays of the present invention will be described in detail below. However, the described embodiments are a part of the embodiments of the invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts are within the scope of the present invention.

An adhesive composition for a liquid crystal display according to an embodiment of the present invention comprises a binder resin and a black pigment, and is applied to an area under the liquid crystal panel of the liquid crystal display, and the liquid crystal panel and the backlight module can be bonded together. . The binder resin preferably uses a two-component polyurethane. The two-component polyurethane means a polyurethane formed by mixing an isocyanate compound and a polyhydroxy compound. One-component polyurethanes having a urethane group in a single combination are simple to apply and bond, but are unstable, have high storage conditions, and have lower adhesion than two-component polyurethanes. Even if it is a main feature of the adhesive composition for liquid crystal displays according to an embodiment of the present invention, that is, to prevent bleed, it is difficult to use it in combination with a black pigment. The two-component polyurethane is required to be used in combination with an isocyanate compound and a polyhydroxy compound, but it has a strong adhesive force and can also be used in combination with a black pigment having a light-shielding effect, and preferably a polyurethane is used.

The isocyanate compound may be a diisocyanate compound such as Methylenediphenyl Diisocyanate (MDI), p-phenylene diisocyanate (PPDI), 1,6-hexamethylene diisocyanate (1). , 6-Hexamethylene diisocyanate, HDI), toluene diisocyanate (TDI), 1,5-naphthalene diisocyanate (NDI), isophorone diisocyanate (IPDI), Cyclohexylmethane diisocyanate H12MDI and the like.

The MDI can be SR500 (manufactured by Kumho Mitsui Chemicals Co., Ltd.), M200 (manufactured by Kumho Mitsui Chemicals Co., Ltd.), C930 (manufactured by Chemtura Co., Ltd.), E530D (manufactured by Chemtura Co., Ltd.) or 4,4-methylenediphenyldiene. Isocyanate (4,4'-methylenediphenyl diisocyante, TCI), and the HDI can be 50M-HDI (manufactured by Asahi KASEI Co., Ltd.).

The polyhydroxy compound is preferably a diol compound, and 1,4 butanediol can be used. The diol compound has a commercially available PPG200D (Kumho Oil) Made by Chemical Company), PPG400D (manufactured by Kumho Petrochemical Co., Ltd.), PPG1000D (manufactured by Kumho Petrochemical Co., Ltd.), PPG2000D (manufactured by Kumho Petrochemical Co., Ltd.), PPG3000D (manufactured by Kumho Petrochemical Co., Ltd.), PPG3322 (Kumho Oil) Manufactured by a chemical company, PPG5815 (manufactured by Kumho Petrochemical Co., Ltd.), etc.

The black pigment used in the binder composition for liquid crystal display according to an embodiment of the present invention may be a black substance such as carbon black, iron oxide, carbon nanotube or graphite. The average particle diameter of the black pigment is preferably from 13 to 70 nm. When the size of the particles is too small, it is not dispersed in the bonding resin to prevent a decrease in the bleeding effect. Conversely, if the particles are too large, the adhesion will decrease. However, two or more kinds of black pigments having different particle sizes from each other can be used to sufficiently disperse the black pigment in the composition. The black pigment is preferably carbon black in terms of ease of use and cost. The black pigment is 100 parts by weight of the binder resin, preferably 10 to 30 parts by weight. When the amount of the black pigment added exceeds 30 parts by weight, the adhesive force is reduced, and the light emitted from the backlight module is absorbed by the binder, which reduces the efficiency of the liquid crystal panel. On the other hand, when the amount of the black pigment added is less than 10 parts by weight, the problem of bleeding cannot be effectively prevented.

An adhesive composition for a liquid crystal display according to an embodiment of the present invention contains an adhesive resin and a black pigment, and contains an elastic resin and a hardening accelerator. The elastic resin can improve the adhesion of the pressure-sensitive adhesive composition for a liquid crystal display according to an embodiment of the present invention and increase the elongation. When a liquid crystal display is manufactured, if a physical bending phenomenon occurs during the process of implementing the process, the liquid crystal panel and the backlight module are likely to be separated. The increased elongation can reduce the incidence of such adverse problems. Or maintain adhesion under harsh conditions and thermal shock conditions.

The elastic resin is used in an amount of 5 to 30 parts by weight based on 100 parts by weight of the binder resin. The addition amount of the elastic resin exceeds 30 parts by weight, which in turn causes a decrease in adhesion. When the amount is less than 5 parts by weight, the adhesive strength is insufficient and the durability is also lowered. The elastic resin may be an epoxy resin. The elastomeric resin is preferably at a viscosity of 25,000 to 30,000 cPs at 45 ° C and has a physical property of a molecular weight of 5,500 to 6,000 g/mol. For example, polybutadienes, glycidyl esters, epoxy novolacs or bisphenol A types can be used. Further, the epoxy resin may be a commercially available PB3600 (manufactured by DALCEL Chemical Co., Ltd.). PB4700 (manufactured by DALCEL Chemical Co., Ltd.) and VTBN (manufactured by CVC Thermoset Specialties).

The binder resin is applied at a normal temperature after the polymerization reaction is caused by mixing of the isocyanate compound and the polyhydroxy compound, and thus the binder resin is rapidly hardened, and the hardener is added in an amount of 1 to 10 parts by weight. When the amount is more than 10 parts by weight, the binder composition for a liquid crystal display according to an embodiment of the present invention is excessively hardened during coating and the adhesive strength is lowered. When the amount added is less than 1 part by weight, the curing time of the adhesive composition is long and the process efficiency is lowered. The hardening agent may be dibutyltin dilaurate, 2-(methylamino)ethanol or the like.

The adhesive composition for a liquid crystal display according to an embodiment of the present invention may further contain 0.05 to 20 parts by weight of the inorganic filler. The inorganic filler may be selected from one or a mixture of two or more inorganic fillers such as ceria, alumina, clay or talc. As the inorganic filler, commercially available Aerosil R8200 (manufactured by EVONIK Co., Ltd.) or Aerosil R200 (manufactured by EVONIK Co., Ltd.) can be used.

A method for producing an adhesive composition for a liquid crystal display according to another embodiment of the present invention includes the following steps of: preparing a first mixture containing an isocyanate compound; preparing a second comprising a polyhydroxy compound, a black pigment, an elastic resin, and a hardening accelerator Mixing the first mixture and the second mixture into a two-component syringe; and pressurizing the first mixture and the second mixture placed in the two-component syringe The mixer formed by the discharge port at the end of the two-component syringe is mixed and discharged.

The components such as an isocyanate compound, a polyhydroxy compound, a black pigment, an elastic resin, and a hardening agent contained in the pressure-sensitive adhesive composition for a liquid crystal display according to the embodiment of the present invention have been described above, and the description thereof will not be repeated.

The isocyanate compound is prepared by measuring the container, and the second mixture of the polyol, the black pigment, the elastic resin and the hardening agent is prepared in other containers. It is prepared based on the sum of the amounts of the isocyanate compound and the polyhydroxy compound added. That is, the black pigment is added in an amount of 10 to 30 parts by weight, the elastic resin is added in an amount of 10 to 30 parts by weight, and the hardening accelerator is added in an amount of 1 to 10 parts by weight based on 100 parts by weight of the isocyanate compound and the polyhydroxy compound. Separating the separately prepared first mixture and the second mixture at room temperature or Also put in a two-component syringe. The first mixture and the second mixture are charged in a volume ratio of 50:40 to 50:60. Pressurizing the first mixture and the second mixture introduced into the two-component syringe is discharged from a discharge port at the end of the two-component syringe. A mixer that mixes the first mixture and the second mixture is formed on the discharge port. The first mixture and the second mixture which are mixed are a binder which forms the bonding resin while generating a reaction. The adhesive is applied to a portion of the liquid crystal panel or a portion of the backlight module during the manufacturing process of the liquid crystal display to bond the liquid crystal panel and the backlight module.

The present invention will be further described in detail below in conjunction with specific embodiments. However, the technical solution of the present invention is not limited.

Example 1

[Manufacture of two-component polyurethane adhesive composition]

100 g of PTMEG-type isocyanate (E530D, manufactured by Chemtura Co., Ltd.) was placed in a container to prepare a mixture A.

In a container different from the mixture 1, 43.14 g of polypropylene glycol (PPG2000D, manufactured by Kumho Petrochemical Co., Ltd.), 19.61 g of carbon black (TBK 1099R, manufactured by CABOT Co., Ltd.), and polybutadiene epoxy resin (PB3600, DALCEL Chemical Co., Ltd.) were prepared. Manufactured: 29.41 g, 1.86 g of dibutyltin dilaurate (manufactured by Aldrich Co., Ltd.), and 5.88 g of gas phase cerium oxide (aerosil 8200, manufactured by EVONIK Co., Ltd.).

The viscosity of the mixture A and the mixture B measured by RE-215U (Toki Sangyo Co., Ltd.) at this time was 38,300 cPs and 46,000 cPs, respectively.

The mixture A and the mixture B were extruded in a 500 ml cylindrical two-component syringe at a volume ratio of 50:50.

Example 2

[Manufacture of two-component polyurethane adhesive composition]

100 g of isocyanate (E530D, manufactured by Chemtura Co., Ltd.) was placed in a container to prepare a mixture A.

Prepare polypropylene glycol (PPG2000D, Kumho) in a different container than mixture A 49.00 g, carbon black (TBK 1099R, manufactured by CABOT Co., Ltd.), 22.20 g, polybutadiene epoxy resin (PB3600, manufactured by DALCEL Chemical Co., Ltd.), 26.60 g, dibutyltin dilaurate (manufactured by Aldrich Co., Ltd.) 2.20 g.

The viscosity of the mixture A and the mixture B measured by [RE-215U (Toki Sangyo)] at this time was 38,300 cPs and 6,100 cPs, respectively.

The mixture A and the mixture B were extruded in a 500 ml cylindrical two-component syringe at a volume ratio of 50:50.

Example 3

[Manufacture of two-component polyurethane adhesive composition]

100 g of isocyanate (E530D, manufactured by Chemtura Co., Ltd.) was placed in a container to prepare a mixture A.

In a container different from the mixture A, 45.83 g of polypropylene glycol (PPG2000D, manufactured by Kumho Petrochemical Co., Ltd.), 20.84 g of carbon black (TBK 1099R, manufactured by CABOT Co., Ltd.), and polybutadiene epoxy resin (PB3600, DALCEL Chemical Co., Ltd.) were prepared. Manufactured: 31.25 g, dibutyltin dilaurate (manufactured by Aldrich Co., Ltd.) 2.08 g.

The viscosity of the mixture A and the mixture B measured by [RE-215U (Toki Sangyo)] at this time was 38,300 cPs and 10,000 cPs, respectively.

The mixture A and the mixture B were extruded in a 500 ml cylindrical two-component syringe at a volume ratio of 50:50.

Comparative example 1

100 g of isocyanate (E530D, manufactured by Chemtura Co., Ltd.) was placed in a container to prepare a mixture A.

In a container different from the mixture A, 55.42 g of polypropylene glycol (PPG2000D, manufactured by Kumho Petrochemical Co., Ltd.), 25.64 g of carbon black (TBK 1099R, manufactured by CABOT Co., Ltd.), and polybutadiene epoxy resin (PB3600, DALCEL Chemical Co., Ltd.) were prepared. Manufactured: 15.38 g of dibutyltin dilaurate (manufactured by Aldrich Co., Ltd.) 2.56 g.

The viscosity of the mixture A and the mixture B measured by [RE-215U (Toki Sangyo)] at this time was 38,300 cPs and 4,000 cPs, respectively.

The mixture A and the mixture B were extruded in a 500 ml cylindrical two-component syringe at a volume ratio of 50:50.

[Evaluation Performance]

Evaluation of adhesion properties

The adhesive compositions produced in Examples 1, 2, and 3 and Comparative Example 1 were coated on a glass plate at a thickness of 500 μm. The glass plate was joined to other glass plates or PC substrates, and after 12 hours, the adhesion was measured by a dynamic shearing method and a peeling (Peel Off) method. The results are shown in Table 1.

Assessment to prevent bleed

The adhesive compositions produced in Examples 1, 2, and 3 and Comparative Example 1 were coated on a glass plate at a thickness of 500 μm. After 12 hours, the absorbance was measured using UV at 400-600 nm. The results are shown in Table 1.

Evaluate elongation

The adhesive compositions produced in Examples 1, 2, and 3 and Comparative Example 1 were coated on a glass plate at a thickness of 500 μm and a width of 10 μm. The elongation was measured with a hardened test piece after 12 hours. The results are shown in Table 1.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention, and any person skilled in the art can make some changes and refinements without departing from the spirit and scope of the present invention. The scope of protection of this creation is subject to the definition of the scope of the patent application.

Claims (12)

An adhesive composition suitable for use in a liquid crystal display comprising: 100 parts by weight of a binder resin; and 10 to 30 parts by weight of a black pigment applied to a liquid crystal of the liquid crystal display a bottom of the panel or an upper portion of a backlight module of the liquid crystal display to engage the liquid crystal panel and the backlight module. The adhesive composition of claim 1, wherein the binder resin is a two-component polyurethane resin. An adhesive composition suitable for use in a liquid crystal display comprising: 100 parts by weight of a binder resin; 10 to 30 parts by weight of a black pigment; 10 to 30 parts by weight of an elastic resin; and 1 to 10 parts by weight The adhesive composition is applied to a bottom of a liquid crystal panel of the liquid crystal display or an upper portion of a backlight module of the liquid crystal display to bond the liquid crystal panel and the backlight module. The adhesive composition of claim 3, wherein the binder resin is a two-component polyurethane resin. The adhesive composition of claim 3, wherein the black pigment comprises at least one selected from the group consisting of carbon black, carbon nanotubes, and graphite. The adhesive composition according to claim 5, wherein the black pigment has an average particle diameter of 13 to 70 nm. The adhesive composition according to claim 3, further comprising 0.05 to 20 parts by weight of at least one selected from the group consisting of ceria, alumina, clay and talc. The adhesive composition according to claim 3, wherein the elastic resin has a viscosity of 25,000 to 30,000 cPs and a molecular weight of 5,500 to 6,000 g/mol. The adhesive composition of claim 3, wherein the elastic resin is an epoxy resin. A method for producing an adhesive composition suitable for a liquid crystal display, comprising: preparing a first mixture comprising an isocyanate compound; preparing a second mixture comprising a polyhydroxy compound, a black pigment and a hardening agent ;as well as The first mixture and the second mixture are placed in a two-component injection container. A method of producing an adhesive composition suitable for a liquid crystal display according to claim 3, wherein a volume ratio of the first mixture to the second mixture is 50:40 to 40:60. A method of using an adhesive composition suitable for a liquid crystal display, comprising: storing a first mixture and a second mixture in a two-component injection container, the two-component injection container having a mixing with a row of outlets separated from each other, the first mixture comprising an isocyanate compound, and the second mixture comprising a polyhydroxy compound, a black pigment, and a hardening agent; and mixing the first mixture with the mixer The second mixture is then discharged through the discharge port to a mixed mixture having the first mixture and the second mixture.