TWI490299B - Acrylic adhesive composition and use thereof - Google Patents

Description

Acrylic adhesive composition and use thereof

The present invention relates to an adhesive composition; in particular, the present invention relates to a curable acrylic adhesive composition which can be used as an adhesive for an optical laminate such as a touch panel display.

In recent years, electronic products have emphasized the characteristics of light, thin, short, and small, in order to enhance the convenience of use, and to make liquid crystal displays, especially thin-film transistor liquid-crystal display (TFT-LCD) market. It has grown rapidly and has largely replaced traditional CRT (cathode ray tube) displays. Related industries have begun to improve the fineness of the display, color performance, and enhance the convenience of use. This trend has led to the development of technologies such as 3D displays and touch panels.

The touch panel is usually provided with a liquid crystal panel to provide a touch panel display, and is widely used in electronic products such as smart phones, tablet computers, MP3s, and car navigation systems, and the most common touch panel display products on the market are mainly distinguishable. In order to use the resistive touch panel and the capacitive touch panel. In summary, the resistive touch panel mainly comprises a supporting substrate (such as PC plastic or glass), and two layers of conductive film substrates respectively form upper and lower electrodes, a decoration film, and a supporting substrate and Adhesives are used to bond each other between the film substrates and between the film substrate and the decorative film; when the panel is touched with a finger or a stylus, the two layers of the conductive film substrate are subjected to voltage changes due to contact, and then The voltage change is converted into a digital signal by the controller, and the position of the contact point is calculated through a computer operation, thereby performing an access operation to the host. Capacitive touch panels usually use conductive glass with patterned ITO on one surface, one side is attached to a liquid crystal panel module (LCM), and the other side is covered with a cover lens (such as PC plastic or glass). The surface durability is enhanced, and a uniform electric field is established on the surface of the ITO conductive glass to sense the weak current when the human body touches, thereby achieving the purpose of touch.

At present, most of the industry uses optically clear adhesive (OCA) and liquid optical clear adhesive (LOCA) with high light transmittance as an adhesive for bonding optical materials, for example, for a protective film layer of a liquid crystal panel. The bonding, the bonding between the liquid crystal panel and the touch panel, and the bonding between the layers in the touch panel. Among them, the optical glue is a kind of pressure sensitive adhesive, the main component is acrylic polymer, which is commonly used in the soft board to the hard board processing (roller to film); however, the edge of the laminated laminated board is due to the design and application requirements. (such as the frame-like edge of the decorative film), there is a difference in thickness, that is, there is a phenomenon of high and low step difference. Therefore, when the existing optical glue is used for bonding, the laminated plates cannot be closely adhered to each other, and bubbles are easily generated, resulting in a decrease in process yield. .

In addition, the main components of water gel used in the industry are acrylic oligomers and/or monomers, which have low viscosity before curing, can be rapidly processed by photocuring, and have rework property (ie, fit). After the completion, the film can be peeled off and reused. Therefore, it is mainly used for the processing of the hard board by the hard board; however, the problem often encountered when using the existing water glue for lamination is that the hardness of the water gel after curing is improved. Insufficient elasticity reduces the reworkability and/or increases the amount of glue remaining on the optical laminate during rework.

In view of this, the present invention provides an improved acrylic adhesive which can be used to improve the step phenomenon caused by the use of optical glue, thereby reducing and avoiding the generation of bubbles, and improving the reworkability of the water gel, and solving the disadvantages of the conventional glue. To improve production yield.

It is an object of the present invention to provide an adhesive composition comprising:

(a) an acrylic oligomer having at least one unsaturated group, an acrylic polymer having a group selected from the group consisting of a hydroxyl group, an amine group, a carboxylic acid group, and a combination thereof, or both Mixture

(b) a photopolymerizable monomer;

(c) a photoinitiator;

(d) a plasticizer comprising a compound of formula (I), a compound of formula (II), or a mixture of the two:

Wherein R ₁ and R ₂ are each independently hydrogen, an aliphatic or an aromatic group, R ₃ is a hydrogen or an aliphatic group, and n 1 is an integer of 1 to 20;

Wherein A is an alkyl group, a phenyl group or a cycloalkyl group, and R ₄ and R ₅ are each independently an aliphatic group; and wherein the weight ratio of component (d) to component (a) is about 0.04 About 0.63.

Another object of the present invention is to provide an optical laminate comprising a first transparent or translucent substrate, a second transparent or translucent substrate, an adhesive composition as described above, which is included in the first transparent substrate and Between the second transparent substrates.

The detailed description of the present invention and the preferred embodiments thereof will be described in the following description.

The invention will be described in detail below with reference to the specific embodiments of the present invention. The invention may be practiced in various different forms without departing from the spirit and scope of the invention. The person stated. In addition, the terms "a", "an" and "the"

The adhesive composition of the present invention comprises: (a) an acrylic-based oligomer, an acrylic polymer, or a mixture of the two; (b) a photopolymerizable monomer; (c) a a photoinitiator; and (d) a plasticizer. Specifically, by adding a specific plasticizer component, the adhesive composition of the present invention can reduce the step phenomenon caused by the use of the conventional optical glue, thereby reducing or avoiding the generation of bubbles, and on the other hand, avoiding the use of the traditional water gel. At the time, the substrate is broken due to heavy-duty operation, and the amount of residual glue is reduced, and the reworkability is improved.

In the adhesive composition of the present invention, component (a) may be an acrylic oligomer having at least one unsaturated group, having a group selected from the group consisting of a hydroxyl group, an amine group, a carboxylic acid group, and a combination thereof. A group of acrylic polymers or a mixture of the two. In the case where an acrylic oligomer is used as the component (a), the resulting adhesive composition is advantageously applied in a coating manner, such as a hydrocolloid form; preferably, a compound having at least two unsaturated groups is used, preferably a system. The use of a group having two unsaturated groups, wherein the unsaturated group is, for example, an ethylenically unsaturated group, and the weight average molecular weight of the acrylic oligomer is usually about greater than or equal to about 2,000, preferably about 10,000 to About 50,000. Acrylic oligomers which can be used in the adhesive composition of the present invention include, for example but are not limited to: aliphatic urethane diacrylate, aliphatic urethane hexaacrylate, Polyester diacrylate, polyester tetraacrylate, polyester hexaacrylate, polyether polyol, aliphatic urethane Acrylate), PPG-modified acrylate, or any combination of the foregoing.

Commercially available acrylic oligomer products can also be used directly, such as 6114, 6115J-80, 6123, 6144-100, 6145-100, 6148J-75, 615-100, 6150-100, 6161 sold by Changxing Chemical Manufacturing Co., Ltd. -100, 6172-1, 6177, 6181, 6191, 6323-100, 6225-100, 6336-100, DRU301, 6127, ETERCURE 3000A-2, and the like. In the attached examples, ETERCURE 3000A-2 was used as the component (a) acrylic oligomer.

According to the invention, component (a) may also be an acrylic polymer having a group selected from the group consisting of hydroxyl groups, amine groups, carboxylic acid groups, and combinations thereof, preferably hydroxyl groups, and the acrylic acid used. The weight average molecular weight of the polymer is generally from about 100,000 to about 1,000,000, preferably from about 300,000 to about 600,000. When an acrylic polymer is used as the component (a), it is usually a high-consistency adhesive composition, which is advantageous for application in which the entire film is directly bonded (for example, a soft plate to a hard plate), that is, optical. Glue form.

The acrylic polymer which can be used in the adhesive composition of the present invention contains an acrylic polymer having an acrylic-based monomer as a polymerization unit. Suitable monomers are not particularly limited, and include, but are not limited to, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate. , hydroxyethyl acrylate, hydroxyethyl methacrylate, butyl acrylate, butyl methacrylate, ethylhexyl acrylate, Ethylhexyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate, cyclohexyl acrylate, Cyclohexyl methacrylate, phenoxyethyl acrylate, phenoxyethyl methacrylate, isobornyl acrylate, isobornyl methacrylate (isobornyl methacrylate), tetrahydrofurfuryl acrylate, tetrahydrogen methacrylate Tetrahydrofurfuryl methacrylate, acryloyl morpholine, acrylonitrile, α-methacrylonitrile, glycidyl methacrylate, methyl Benzyl methacrylate, or any combination of the foregoing.

According to the acrylic polymer in the adhesive composition of the present invention, in addition to the polymer formed by using the acrylic monomer as the polymerization unit as described above, the acrylic monomer and other monomers as described above may also be used. The polymer formed as a polymer unit comprising, for example, styrene and its derivatives, α-methylstyrene, maleic anhydride, vinyl acetate ( Vinyl acetate), N-vinyl-2-pyrrolidone, vinylpyridine, vinylpropionate, or any combination of the foregoing.

Commercially available products include ETERAC 7780, ETERAC 77308, and ETERAC 77095 (manufactured by Changxing Chemical Co., Ltd.) as sold by Changxing Chemical. In the attached examples, ETERAC 7780 was used as the component (a) acrylic polymer.

In addition to component (a), the adhesive composition of the present invention also comprises component (b) a photopolymerizable monomer, usually an acrylate monomer, including, for example, a monofunctional acrylate monomer, a polyfunctional acrylic acid. The ester monomer, or a mixture of the foregoing. According to the present invention, the kind and amount of the photopolymerizable monomer are generally adjusted depending on the kind of the component (a), the added amount, and the use of the resulting adhesive composition; for example, a monofunctional acrylate monomer may be added as a group. Sub-(b), the monofunctional acrylate monomer has a function as a diluent, and the viscosity of the obtained adhesive composition can be appropriately adjusted to improve the workability of coating application; and a polyfunctional acrylate monomer can also be used as a component ( b) In this case, more functional groups can be reacted, which is advantageous for the subsequent curing reaction. Those having ordinary knowledge in the art, according to the disclosure content of the present specification and related knowledge, can adjust the type and amount of component (a) and component (b) as needed to obtain an adhesive composition having a desired property, such as a group. A mixture of an acrylic oligomer and an acrylic polymer may be used in the component (a), and a mixture of a monofunctional acrylate monomer and a polyfunctional acrylate monomer may be used for the component (b).

Component (b) photopolymerizable monomer which can be used in the adhesive composition of the present invention includes, but is not limited to, lauryl acrylate, isooctyl acrylate, stearyl methacrylate (stearyl(meth)acrylate), isodecyl acrylate, pentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, isoborny (meth) Acrylate), 2-(2-ethoxyethoxy)ethyl acrylate, acrylic acid, butyl acrylate, 2-hydroxyethyl acrylate 2-hydroxyethyl acrylate (HEA), 2-hydroxyethyl methacrylate (HEMA), polyethylene glycol diacrylate, 1,4-butanediol di(A) 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol N-(meth)acrylate (neopentylglycol di(meth)acrylate), 2-methyl- 2-methyl-1,3-propanediol diacrylate, ethoxylated 2-methyl-1,3-propanediol diacrylate 2-butyl-2-ethyl-1,3-propanediol diacrylate, propoxylated neopentyl glycol diacrylate ), or any combination of the foregoing.

The photopolymerizable monomer which can be used in the present invention (b) is preferably selected from the group consisting of lauryl acrylate, dipentaerythritol hexaacrylate, isobornyl (meth) acrylate (isoborny ( Meth)acrylate), 2-(2-ethoxyethoxy)ethyl acrylate, acrylic acid, butyl acrylate, 2-hydroxy acrylate Ethyl 2-ethylethyl acrylate (HEA), or any combination of the foregoing. Commercially available acrylate monomers such as EM70, EM23, EM20, EM24, EM211, EM215, EM218, EM219, EM265, EM2251, EM315, EM35 manufactured by Changxing Chemical can also be used directly. In the appended examples, EM215 or EM265 was used as the component (b) photopolymerizable monomer.

In accordance with the teachings of the present specification, one of ordinary skill in the art can select the amount of component (b) photopolymerizable monomer as desired. For example, in the case where the acrylic oligo (a) is used in combination with the monofunctional acrylate monomer (b), the weight ratio of the component (b) to the component (a) is from about 0.2 to about 1.8. It is preferably from about 0.4 to about 1.5; in the case where the polyfunctional acrylate monomer (b) is combined using the acrylic polymer (a), the weight ratio of the component (b) to the component (a) is about From 0.01 to about 0.5, preferably from about 0.04 to about 0.2.

The adhesive composition of the present invention should further comprise component (c) a photoinitiator to absorb the light source and initiate polymerization of the acrylic oligomer, the acrylic polymer and the photopolymerizable monomer in the composition, ie Curing is carried out. Component (c) photoinitiator suitable for use in the present invention may, for example, but not limited to, selected from the group consisting of benzophenone, hydroxycyclohexylbenzophenone, 2,4,6-trimethyl 2,4,6-trimethylbenzoyl diphenyl phosphine oxide, bis-4,4'-diethylaminobenzophenone, benzo Benzophenone, camphorquinone, 3,5-bis(diethylaminobenzylidene)-N-methyl-4-piperidone (3,5-bis(diethylaminobenzylidene)-N- Methyl-4-piperidone), 3,5-bis(dimethylaminobenzylidene)-N-methyl-4-piperidone (3,5-bis(dimethylaminobenzylidene)-N-methyl-4- Piperidone), 3,5-bis(diethylaminobenzylidene)-N-ethyl-4-piperidone, 3 , 3'-carbonyl-bis(7-diethylamino) cumarin, 3,3'-carbonyl-bis(7-dimethyl 3,3'-carbonyl-bis(7-dimethylamino)cumarin, riboflavin tetrabutyrate, 2-methyl-1-[4-(methylthio Phenyl]-2-morpholinylpropan-1-one (2-meth Yl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one), 2,4-dimethylthioxanthone, 2,4-diethyl 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone, 3,5-dimethylthioxanthone (3,5-dimethylthioxanthone) 3,5-dimethylthioxanthone), 3,5-diisopropylthioxanthone, 1-phenyl-2-(ethoxycarbonyl)oxyiminopropan-1- Ketone (1-phenyl-2-(ethoxycarbonyl)oxyiminopropan-1-one), benzoin ether, bezoin isopropyl ether, benzathrone, 5-nitroguanidine 5-nitroacenaphthene), 2-nitrofluorene, anthrone, 1,2-benzanthraquinone, 1-phenyl-5-mercapto-1H-tetra 1-phenyl-5-mercapto-1H-tetrazole, thioxanthen-9-one, 10-thioxanthenone, 3-mercaptopurine (3- Acetylindole), 2,6-di(p-dimethylaminobenzal)-4-carboxycyclohexanone, 2,6-di (2,6-di(p-dimethylaminobenzal)-4-carboxycyclohexanone) Right two 2,6-di(p-dimethylaminobenzal)-4-hydroxycyclohexanone, 2,6-di(p-diethylaminobenzylidene)- 4-carboxycyclohexanone (2,6-di(p-diethylaminobenzal)-4-carboxcyclohexanone), 2,6-di(p-diethylaminobenzylidene)-4-hydroxycyclohexanone (2, 6-di(p-diethylaminobenzal))-4-hydroxycyclohexanone), 4,6-dimethyl-7-ethylamino-based coumarin (4,6-dimethyl-7-ethylaminocumarin), 7-diethylamine 7-diethylamino-4-methylcumarin, 7-diethylamino-3-(1-methylbenzimidazolyl)coumarin (7-diethylamino-3-() 1-methylbenzoimidazolyl) cumarin), 3-(2-benzimidazolyl)-7-dimethylethylamino coumarin (3-(2-benzoimidazolyl)-7-diethylaminocumarin), 3-(2-benzo-) 3-(2-benzothiazolyl)-7-diethylaminocumarin, 2-(p-dimethylaminostyryl)benzoxazole (2-(p) -dimethylaminostyryl)benzoxazole), 2-(p-dimethylaminostyryl)quinoline, 4-(p-dimethylaminostyryl)quinoline (4- (p-dimethylami Nostyryl)quinoline), 2-(p-dimethylaminostyryl)benzothiazole, 2-(p-dimethylaminostyryl)-3,3 -2-(p-dimethylaminostyryl)-3,3-dimethyl-3H-indole), and combinations thereof; preferred photoinitiators are hydroxycyclohexylbenzophenone, 2, 4,6-Trimethylbenzimidyldiphenylphosphine oxide, or a combination thereof.

The kind and amount of the photoinitiator are generally determined depending on the kind of the photopolymerizable monomer, the oligomer, and the polymer to be used. For example, in the adhesive composition of the present invention, the weight ratio of the component (c) photoinitiator to the component (a) is from about 0.001 to about 0.3, preferably from about 0.003 to 0.2; If the amount of the agent added is too low, the curing effect of the adhesive composition may be incomplete, and conversely, the properties of the cured product may be unfavorable, and even yellowing may occur.

In addition to the above components, another essential component of the adhesive composition of the present invention is component (d) plasticizer. Without being bound by theory, the salty plasticizer can reduce the adhesive combination by plasticization. The glass transition temperature of the object reduces the mechanical modulus of the adhesive composition, which can improve the above-mentioned step and reworkability. The plasticizer which can be used in the adhesive composition of the present invention comprises a compound of the following formula (I), a compound of the following formula (II), or a mixture of the foregoing:

Wherein R ₁ and R ₂ are each independently hydrogen, an aliphatic or an aromatic group, preferably each independently a C ₂ to C ₂₀ aliphatic group, more preferably each independently a C ₄ to C ₁₀ alkyl group, for example Pentyl, hexyl, heptyl and the like. R ₃ is hydrogen or an aliphatic group, preferably hydrogen or a C ₁ to C ₁₀ aliphatic group, more preferably hydrogen or a C ₁ to C ₆ alkyl group such as a methyl group, an ethyl group, a propyl group or the like. N1 is an integer from 1 to 20, preferably an integer from 2 to 10, more preferably from 2 to 6. Plasticizers of the compound of formula (I) which can be used in the adhesive composition of the present invention include, for example, but are not limited to, polyethylene glycol-200-diethylhexoate, ethylenediamine diisooctyl Triethylene glycol bis (2-ethylhexanoate), triglycol diacetate, polypropylene glycol-200-diethylhexoate, or any combination of the foregoing.

In the following examples, ETERCURE DR-E526 and ETERCURE PPG200 sold by Changxing Chemical Co., Ltd. were used as the plasticizer of the formula (I).

The compound of formula (II) has the formula:

Wherein A is a phenyl group or a C ₃ to C ₁₂ cycloalkyl group, preferably a phenyl group or a C ₃ to C ₁₂ cycloalkyl group, for example . R ₄ and R ₅ are each independently an aliphatic group, preferably each independently a C ₆ to C ₂₄ aliphatic group, more preferably each independently a C ₆ to C ₁₃ alkyl group such as an anthracenyl group, a fluorenyl group or the like. The plasticizer of the compound of the formula (II) which can be used in the adhesive composition of the present invention includes, for example but not limited to: diisononyl phthalate, diisodecyl phthalate, ortho Bis(2-propylheptyl) phthalate, 1,2-cyclohexanedicarboxylic acid (diisononyl ester), or any combination of the foregoing .

In the attached examples, the Hexamoll sold by BASF is used. DPHP, DINCH is a plasticizer of formula (II).

Further, in the adhesive composition of the present invention, the weight ratio of the component (d) plasticizer to the component (a) is from about 0.04 to about 0.63, preferably from about 0.06 to about 0.30. If the amount of the plasticizer added is too low, the mechanical modulus of the resulting adhesive is too high, causing the film to rupture; if the amount of the plasticizer added is too high, the mechanical strength of the film is lowered.

The adhesive composition of the present invention may also be added with a crosslinking agent as needed to cause chemical bonding between different resin molecules to form crosslinking. The type and amount of the crosslinking agent are generally adjusted depending on the type of the acrylic oligomer, the polymer used, and the adhesive composition, and may be, for example, but not limited to, diisocyanate or polyisocyanate. Examples include, for example, 1,6-diisocyanatohexane, isophorone diisocyanate, 4,4'-diphenylmethanediisocyanate Tolylene diisocyanate, commercially available as sold by Bayer I or Desmodur 3390, ETERAC 92 sold by Changxing Chemical. According to the adhesive composition of the present invention, when the crosslinking agent is added, the weight ratio to the component (a) is from about 0.001 to about 0.2, preferably from about 0.004 to about 0.08.

In addition, the adhesive composition of the present invention may be added with any suitable tackifier as needed in order to adjust the viscosity of the adhesive composition to a degree suitable for coating or a desired concentration without impairing the purpose of the present invention. For example, but not limited to, rosin-based resins, terpene-based resins, styrenic copolymers, aliphatic petroleum resins, or the foregoing Any combination thereof is preferably selected from the group consisting of C ₅ hydrocarbon resin, hydrogenated C ₅ hydrocarbon resin, styrenated C ₅ resin, C ₅ /C ₉ resin, styrene styrene resin, fully hydrogenated or partially hydrogenated C ₉ hydrocarbon resins, rosin resins, rosin derivatives, polyterpene resins, and mixtures thereof. Commercially available products include GA-100, which is sold by Nichimen, Hikorez A-1100S and Sukorez SU-100, which are sold by Kolon, and Piccotac 1095, Piccotac 1100, and Kristalex 3100, which are sold by Eastman. Regalite R-125, Regalite C6100; Quintone U-185 sold by Zeon Corporation; Escorez 5300 series, Escorez 5400 series, Escorez 5600 series sold by Exxon Mobil. According to the adhesive composition of the present invention, when the tackifier is added, the weight ratio of the tackifier to the component (a) is from about 0.05 to about 1, preferably from about 0.1 to about 0.6.

In addition to the above ingredients, the adhesive composition of the present invention may optionally contain an appropriate amount of solvent to adjust the solid content to facilitate coating. The solvent to be used in the present invention is not particularly limited and may be any one of ordinary skill in the art to which the present invention pertains, such as, but not limited to, alkanes, aromatic hydrocarbons, ketones, esters, alcohols, and ethers. a group consisting of alcohols. Specific examples of the solvent which can be used in the present invention include, but are not limited to, toluene, xylene, ethyl acetate, methyl ethyl ketone, acetone, or a combination of the foregoing.

The adhesive composition of the invention has excellent light transmittance, and can adjust the type and proportion of each component as needed to obtain an adhesive composition having desired characteristics, and is particularly suitable for various optical displays, such as a resistive touch panel. Display, capacitive touch panel display, 3D display, etc.

Accordingly, the present invention further provides an optical laminate comprising a first transparent or translucent substrate, a second transparent or translucent substrate, and an adhesive composition as described above, the adhesive composition being included in the first A transparent substrate and the second transparent substrate.

According to the present invention, the material of the first transparent or translucent substrate and the second transparent or translucent substrate mainly depends on the use of the desired optical laminate, such as providing a resistive touch panel or capacitive touch. panel. Anyone having ordinary knowledge in the technical field can select any suitable first substrate and second substrate according to the disclosure of the present specification. For example, the materials of the first substrate and the second substrate can be independently optical. Glass, PC plastic board, ITO glass, ITO-PET film, liquid crystal panel, touch panel, decorative film, outer protective film, etc.

According to the present invention, when the optical laminate is bonded using the adhesive composition of the present invention, it may be generally included, but not limited to, the above-described adhesive composition is formed first by screen-printing, coating or dispensing. On the substrate, the surface of the first substrate having the adhesive composition is bonded to the second substrate. The above coating methods are well known to those skilled in the art, such as knife coating, roller coating, micro gravure coating, flow coating. (flow coating), dip coating, spray coating, and curtain coating or a combination of the above methods. According to a preferred embodiment of the present invention, the following two modes are as follows:

(1) Adhesive composition in the form of a water gel:

Applying the adhesive composition to a first substrate (such as optical glass), and bonding the coated first substrate to a second substrate (such as optical glass) with a coating surface, followed by UV exposure, The adhesive composition is cured to conform to the first substrate and the second substrate.

(2) Adhesive compositions in the form of optical adhesives:

The adhesive composition is first applied to a release film, followed by drying (for example, at a temperature of about 100 ° C to about 140 ° C for about 1 minute to about 3 minutes) and UV exposure treatment to obtain a film. . Then, after the obtained adhesive film material is imprinted onto a first substrate (such as a decorative film), the first substrate is embossed on the second substrate (such as optical glass) with a film surface, and finally An optical laminate can be formed by performing a defoaming procedure (e.g., at a pressure of about 4 atmospheres to about 6 atmospheres and a vessel of about 40 to 60 °C for about 40 minutes to 80 minutes).

As shown in the attached examples, the optical laminate obtained by laminating the adhesive composition of the present invention has a considerable improvement in the step difference and the reworkability.

The invention is further illustrated by the following specific embodiments.

Example

Preparation of adhesive composition

The adhesive compositions of Examples 1 to 12 and Comparative Examples 1 to 2 of the present invention were prepared according to the ingredients and ratios listed in Tables 1 and 2, respectively, wherein the abbreviations mentioned are defined as follows:

A1: diacrylate oligomer (Changxing Chemical, ETERCURE 3000A-2);

A2: hydroxyl group-containing acrylate polymer (Changxing Chemical, ETERAC 7780);

B1: lauryl acrylate monomer (Changxing Chemical, EM215);

B2: dipentaerythritol hexaacrylate monomer (Changxing Chemical, EM265);

C1: hydroxycyclohexylbenzophenone photoinitiator (Ciba, IRGACURE 184);

Plasticizer (Changxing Chemical, ETERCURE DR-E526);

Plasticizer (Changxing Chemical, ETERCURE PPG200);

Plasticizer (BASF, Hexamoll DPHP);

Plasticizer (BASF, Hexamoll DINCH);

E1: Crosslinker (Bayer, Desmodur I);

E2: crosslinker (Changxing Chemical, ETERAC 92);

F1: tackifier (Exxon Mobil, Escorez 5615).

Example 1

100 parts by weight of the acrylate oligomer (a1), 59.1 parts by weight of the acrylate monomer (b1), 16.2 parts by weight of the plasticizer (d1), and 6.8 parts by weight of the crosslinking agent (e1) are prepared and heated to The mixture was uniformly mixed at 70 ° C, the heat source was removed, and the mixture was continuously cooled to room temperature, and further mixed with 9.7 parts by weight of the photoinitiator (c1) to form the adhesive composition of Example 1.

The obtained adhesive composition is applied by a roller on an optical glass (first substrate) having a thickness of 0.7 mm to form a coating layer, and then the first substrate having the above coating layer is attached to an optical glass having a frame ( On the second substrate), the UV exposure machine (model: F300S+AJ-6-UVL; UV light source: AJM-07/UVICURE Plus II) is exposed three times at a line speed of 4 meters per minute (exposure energy is about 1086). Millijoules per square centimeter). Next, the cutter was cut into a size of 5 cm x 5 cm to form an optical laminate.

Examples 2 to 6

The adhesive compositions of Examples 2 to 6 were prepared according to the components and parts by weight shown in Table 1, the method for producing the adhesive composition, and the method for forming the optical laminate were as described in Example 1.

Example 7

100 parts by weight of a hydroxyl group-containing acrylate polymer (a2), 4.9 parts by weight of an acrylate monomer (b2), 0.3 parts by weight of a photoinitiator (c1), and 16.2 parts by weight of a plasticizer are mixed and mixed at room temperature. The agent (d1) and 0.6 part by weight of the crosslinking agent (e2) were further added with a solvent of toluene/ethyl acetate (weight ratio 1:2) to form an adhesive composition of Example 7 having a solid content (NV) of 28%.

The obtained adhesive composition was coated on a PET release film (Japan Dongshan; model: HY-TS12/50 μm) with a wire coating bar (KODAIRA; model: YBA3; adjustment scale of 3), and the coating was completed. The PET substrate was placed in an oven at 120 ° C for 2 minutes, taken out and placed in a UV exposure machine (model: F300S+AJ-6-UVL; UV light source: AJM-07/UVICURE Plus II) at a line speed of 4 meters/ One minute exposure (about 362 mJ/cm 2 of exposure energy) was applied to a release film (Higashiyama, Japan; model: HY-TS04/50 μm) to form a sheet having a thickness of 50 μm.

The black ink solution was printed on a 188 μm thick optically cured PET film in a 120 mesh screen with a mesh shape of 5 cm x 5 cm, and baked at 70 ° C for one hour to obtain a black ink solution. Decoration film. Next, the above-mentioned sheet is embossed on the obtained decorative film, the PET release film is peeled off, and then embossed on a 0.7 mm optical glass with a protector, cut into 5 cm x 5 cm by a cutter, and placed. The pressure vessel was defoamed at 50 ° C and 5 atm for one hour to form an optical laminate.

Examples 8 to 12

The adhesive compositions of Examples 8 to 12 were prepared according to the components and parts by weight shown in Table 2, the manufacturing method of the adhesive composition, and the method of forming the optical laminate were as described in Example 7.

Comparative example 1

Preparing 100 parts by weight of the acrylate oligomer (a1), 59.1 parts by weight of the acrylate monomer (b1), and 6.8 parts by weight of the crosslinking agent (e1), heating to 70 ° C and stirring to uniformly mix and shift The adhesive composition of Comparative Example 1 was formed by mixing with 9.7 parts by weight of a photoinitiator (c1) in addition to a heat source and continuously stirring to room temperature.

The resulting adhesive composition was formed into an optical laminate as described in Example 1.

Comparative example 2

100 parts by weight of a hydroxyl group-containing acrylate polymer (a2), 4.9 parts by weight of an acrylate monomer (b2), 0.2 parts by weight of a photoinitiator (c1), and 0.4 parts by weight are mixed at room temperature. The crosslinking agent (e1) was further added with a solvent of toluene/ethyl acetate (weight ratio 1:2) to form an adhesive composition of Comparative Example 2 having a solid content (NV) of 28%.

The resulting adhesive composition was formed into an optical laminate as described in Example 7.

[testing method]

(A) Next force test:

The coating of the optical laminates of Examples 1 to 12 and Comparative Examples 1 to 2 was measured at a speed of 180 degrees and 300 mm/min, respectively, using a universal tensile machine (Hongda Instruments, HT-9102) according to the JIS-Z0237 standard method. The adhesion of the film to the substrate.

(B) Light penetration test:

The total light transmittance (Tt) was measured according to the JIS K7361 standard method using an NDH 5000W haze meter (Electric Color Co., Japan).

(C) Heavy work test:

The optical laminate was fixed on the platform, and the two glass substrates were pulled with a nylon rope to observe the separation of the substrate. If two glass substrates are broken during the drawing process, the display shows no reworkability (labeled as X); if the two substrates are smoothly separated during the drawing process and there are residual glue on both sides, the display has good workability (marked) O); If the two substrates can be smoothly separated and the two-side residual glue is evenly distributed during the drawing process, the workability is excellent (labeled as ◎).

(D) Step difference test:

The optical laminate was placed in an environmental tester and placed under conditions of 80 ° C and 60 ° C, 90% RH for 240 hours, respectively, to observe the degree of foaming of the optical laminate before and after environmental testing, if the degree of foaming is high (mark X ) means that the step is serious. If the degree of foaming is not obvious (marked O), the step is slight. If there is no blistering (marked ◎), there is no step.

The test results of Examples 1 to 6 and Comparative Example 1 are shown in Table 3; the test results of Examples 7 to 12 and Comparative Example 2 are shown in Table 4.

As can be seen from the results of Table 3, the adhesive compositions of Examples 1 to 6 have better reworkability than Comparative Example 1, wherein the adhesive compositions of Examples 1 to 2 and Example 6 have superior reworkability. And using an optical laminate of the adhesive composition (Examples 1 to 6) to which the plasticizers d1 to d4 are added, wherein the weight ratio of the component (d) to the component (a) is 0.162, 0.267 and 0.545, respectively. The light transmittance is not affected, and it is shown that the adhesive composition of the present invention can be used to improve the cracking of the substrate which occurs when the optical laminate is reworked, and to reduce the amount of residual glue.

As can be seen from the results of Table 4, the adhesive compositions of Examples 7 to 12 exhibited a slight step difference compared to Comparative Example 2, in which Examples 7 to 9 and Example 11 did not exhibit a step difference. And an adhesive composition (Examples 7 to 12) to which plasticizers d1 to d4 are added, wherein the weight ratio of the component (d) to the component (a) is 0.100, 0.133, 0.162 and 0.200, respectively. The light transmittance of the plate is not affected, and the adhesive composition of the present invention can improve the step of the optical laminate, thereby avoiding the generation of bubbles in the optical laminate and improving the production yield.

In summary, when the adhesive composition of the present invention is applied to the bonding of an optical laminate, the step difference can be reduced, the generation of bubbles can be avoided, and the reworkability is good. Further, the adhesive composition of the present invention maintains good light transmittance and is particularly suitable as an adhesive for optical laminates. At the same time, the characteristics of the obtained adhesive composition can be adjusted by adjusting the types and ratios of the components to improve the flexibility of the application.

The above embodiments are merely illustrative of the principles and effects of the present invention, and are illustrative of the technical features of the present invention and are not intended to limit the scope of the present invention. Any changes or arrangements that can be easily accomplished by those skilled in the art without departing from the technical principles and spirit of the invention are within the scope of the invention. Accordingly, the scope of the invention is set forth in the appended claims.

Claims (13)

An adhesive composition comprising: (a) an acrylic oligomer having at least one unsaturated group, the acrylic oligomer being a polyester diacrylate, a polyester tetraacrylate, a polyester hexaacrylic acid An ester, a polyether polyol, a polypropylene glycol modified acrylate, or any combination of the foregoing; (b) a photopolymerizable monomer; (c) a photoinitiator; and (d) a plasticizer comprising (I) a compound, a compound of formula (II), or a mixture of the two: Wherein R ₁ and R ₂ are each independently hydrogen, an aliphatic or an aromatic group, R ₃ is a hydrogen or an aliphatic group, and n 1 is an integer of 1 to 20; Wherein A is an alkyl group, a phenyl group or a cycloalkyl group, and R ₄ and R ₅ are each independently an aliphatic group; and wherein the weight ratio of component (d) to component (a) is about 0.267 to About 0.63. The adhesive composition of claim 1, wherein component (a) is an acrylic oligomer having two unsaturated groups having a weight average molecular weight of greater than or equal to about 2,000. The adhesive composition of claim 1, wherein the photo-polymerizable single-system acrylate monomer of component (b). The adhesive composition of claim 3, wherein the acrylate system is selected from the group consisting of a monofunctional acrylate monomer, a polyfunctional acrylate monomer, and a mixture of the foregoing. The adhesive composition of claim 1, wherein R ₁ and R ₂ are each independently a C ₂ to C ₂₀ aliphatic group, n 1 is an integer of 2 to 10, and R ₃ is hydrogen or a C ₁ to C ₁₀ aliphatic group. base. The adhesive composition of claim 1, wherein R ₁ and R ₂ are each independently a C ₄ to C ₁₀ alkyl group, n 1 is an integer of from 2 to 6, and R ₃ is hydrogen or a C ₁ to C ₆ alkyl group. The adhesive composition of claim 1, wherein R ₄ and R ₅ are each independently a C ₆ to C ₂₄ aliphatic group, and A is a phenyl group or a C ₃ to C ₁₂ cycloalkyl group. The adhesive composition of claim 1, wherein R ₄ and R ₅ are each independently a C ₆ to C ₁₃ alkyl group, and A is a phenyl group or . The adhesive composition of claim 1, wherein the weight ratio of component (d) to component (a) is from about 0.267 to about 0.30. The adhesive composition of claim 1, further comprising (e) a crosslinking agent. The adhesive composition of claim 1, further comprising (f) a tackifier. The adhesive composition of any one of claims 1 to 11, which is for use in a touch panel display or a 3D display. An optical laminate comprising: a first transparent or translucent substrate; a second transparent or translucent substrate; and an adhesive composition according to any one of claims 1 to 11, which is included in the first transparent Or between the translucent substrate and the second transparent or translucent substrate.