KR20140079755A - Acrylic fine particles and diffusing film comprising the same - Google Patents

Abstract

Acrylic fine particles of the present invention are acrylic fine particles formed by polymerizing a cross-linker to a monomer comprising (meta)acrylate. The cross-linker comprises a first cross-linker containing more than three (meta)acryl groups and at least one kind of functional group among OH and -COOH. The acrylic particles have 20- 60% of dispersion index (C.V). The acrylic particles have high heat resistance and solvent resistance wherein compatibility with a binder and solvent is increased thereby having significantly increased dispersion on a film such as a diffusion film so as to be properly used in a diffusing agent.

Description

TECHNICAL FIELD [0001] The present invention relates to an acrylic-based fine particle and a diffusion film containing the acrylic-

The present invention relates to acrylic fine particles and a diffusion film comprising the same. More particularly, the present invention relates to an acrylic fine particle having excellent compatibility with a binder and a solvent while maintaining high heat resistance and solvent resistance and having excellent dispersibility when applied to a diffusion film, and a diffusion film comprising the acrylic fine particle.

Acrylic fine particles are usefully used for a light diffusing agent, an additive for coating materials, various surface treating agents, and a carrier. Particularly, in the case of acrylic fine particles, they are used as a light diffusing agent for imparting a light diffusion effect of a diffusion film, a light diffusion plate, a lighting apparatus and a billboard.

The acrylic fine particles are mainly prepared by the suspension polymerization method and have a spherical bead shape.

To apply such acrylic fine particles to a diffusion film, the solvent resistance (chemical resistance) of the bead itself is required in order to maintain processability and stability of coating liquid. For this purpose, a method of increasing the degree of crosslinking of acrylic fine particles has been proposed. That is, in order to increase the degree of crosslinking, a crosslinking agent having a high number of crosslinking functional groups is used, or the amount of crosslinking agent is increased to increase the degree of crosslinking. However, when acrylic type fine particles having a high degree of crosslinking and high functional groups are used as a diffusing agent in consideration of the solvent resistance, the compatibility between the solvent and the acrylic type fine particles is poor and the acrylic type fine particles are bundled together. That is, in the case of acrylic fine particles, in the non-polar solvent such as methyl ethyer ketone (MEK), ethanol, and methanol, the acrylic fine particles are not compatible with each other, The diffusion agent is uniformly dispersed and is not coated so that the quality of the product is deteriorated.

Therefore, it is inconvenient to control the selection of the solvent of the coating liquid by the characteristics of the coating and film makers to be applied according to each of the developed diffusion microparticles. Also, there is a problem that the range of techniques for improving various performances such as optical performance and efficiency is reduced There was a problem.

Related prior art documents include US4271283 and KR2010-0075235.

An object of the present invention is to provide acrylic fine particles excellent in compatibility with a binder and a solvent while maintaining a high-quality bridge.

Another object of the present invention is to provide acrylic fine particles which can dramatically increase the dispersibility when applied to a diffusion film.

Another object of the present invention is to provide acrylic fine particles excellent in high heat resistance and solvent resistance.

It is still another object of the present invention to provide a diffusion film having excellent transparency and diffusibility by applying the acrylic fine particles.

One aspect of the present invention relates to acrylic fine particles. The acrylic fine particles are acrylic fine particles formed by polymerizing a cross-linking agent to a monomer containing (meth) acrylate, wherein the cross-linking agent contains at least three (meth) acrylic groups and at least one functional group selected from -OH and -COOH And a first crosslinking agent. The acrylic fine particles may have a dispersion index (C.V) of 20 to 60%, preferably 40 to 60%.

In an embodiment, the first crosslinking agent may be represented by the following formula 1:

[Chemical Formula 1]

(Y) _i -R- (Q) _j

Wherein R is a branched hydrocarbon having 1 to 10 carbon atoms, Q is -OH or -COOH, i is an integer of 3 to 5, and j is an integer of 1 to 5, wherein Y is a (meth) acrylic group, Lt; / RTI >

In an embodiment, the acrylic fine particles may include 60 to 90% by weight of a monomer containing (meth) acrylate and 10 to 40% by weight of a crosslinking agent. For example, the acrylic fine particles may include 60 to 85% by weight of a monomer containing (meth) acrylate and 15 to 40% by weight of a crosslinking agent.

The (meth) acrylate-containing monomer may include an alkyl (meth) acrylate having 1 to 10 carbon atoms and a monomer copolymerizable therewith.

In one embodiment, the (meth) acrylate-containing monomer may include 50 to 100% by weight of an alkyl (meth) acrylate having 1 to 10 carbon atoms and 0 to 50% by weight of a copolymerizable monomer.

The copolymerizable monomer is composed of an aromatic vinyl monomer, a vinyl cyanide monomer, an aromatic (meth) acrylate having 6 to 20 carbon atoms, a hydroxyl group-containing (meth) acrylate, an epoxy group-containing (meth) acrylate and an unsaturated carboxylic acid One or more species from the group.

The crosslinking agent may include 60 to 100% by weight of the first crosslinking agent and 0 to 40% by weight of the second crosslinking agent.

In an embodiment, the crosslinking agent is a crosslinking agent containing at least three (meth) acrylic groups and containing at least one of -OH and -COOH, and a first crosslinking agent containing 1,4-butanediol di (meth) acrylate, (Meth) acrylates such as diol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, ethylene glycol di (meth) acrylate, propylene glycol di (Meth) acrylate, trimethylolpropane tri (meth) acrylate, and ditrimethylolpropane tetra (meth) acrylate.

In one embodiment, the weight ratio of the first crosslinking agent to the second crosslinking agent may be 1.5 to 10: 1.

In an embodiment, the acrylic fine particles may have a swelling degree of less than 10% after 4 hours at 25 DEG C in methyl ethyl ketone.

Another aspect of the present invention relates to a diffusion film comprising the acrylic fine particles.

Another aspect of the present invention relates to a method for producing the acrylic fine particles. The method comprises mixing a monomer containing (meth) acrylate with a crosslinking agent and an initiator to prepare a monomer mixture solution; And suspending and polymerizing the monomer mixture solution, wherein the cross-linking agent includes a first cross-linking agent containing at least one functional group selected from -OH and -COOH containing at least three (meth) acrylic groups.

Disclosure of Invention Technical Problem [10] The present invention relates to an acrylic resin composition which is excellent in compatibility with a binder and a solvent while maintaining a high-quality bridge, has excellent dispersibility when applied to a diffusion film, and has excellent heat resistance and solvent resistance, And a diffusion film excellent in diffusibility.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an SEM photograph for evaluating the solvent dispersibility of acrylic fine particles prepared in Example 1 of the present invention. FIG.
2 is an SEM photograph for evaluating the solvent dispersibility of the acrylic fine particles prepared in Example 2 of the present invention.
3 is an SEM photograph for evaluating the solvent dispersibility of the acrylic fine particles prepared in Comparative Example 1 of the present invention.
4 is an SEM photograph for evaluating the solvent dispersibility of the acrylic fine particles prepared in Comparative Example 2 of the present invention.
5 is an SEM photograph for evaluating the solvent dispersibility of the acrylic fine particles prepared in Comparative Example 3 of the present invention.
6 is an optical microscope photograph for evaluating the solvent dispersibility of the acrylic fine particles prepared in Example 1 and Comparative Example 1 of the present invention.

Hereinafter, specific examples of the present invention will be described in detail. However, the present invention is not limited thereto, and the present invention is only defined by the scope of the following claims.

As used herein, unless otherwise specified, "(meth) acrylate" means that both "acrylate" and "methacrylate" are possible. "(Meth) acrylic acid" also means that both "acrylic acid" and "methacrylic acid" are possible. "(Meth) acrylamide" means that both "acrylamide" and "methacrylamide" are possible.

The acrylic fine particles of the present invention are acrylic fine particles formed by polymerizing a crosslinking agent on a monomer containing (meth) acrylate, and the crosslinking agent comprises a first crosslinking agent. The first crosslinking agent contains at least one functional group selected from the group consisting of -OH and -COOH, which contains at least three (meth) acrylic groups.

In an embodiment, the acrylic fine particles may include 60 to 90% by weight of a monomer containing (meth) acrylate and 10 to 40% by weight of a crosslinking agent. Preferably 60 to 85% by weight of a monomer containing (meth) acrylate and 15 to 40% by weight of a crosslinking agent. The solvent resistance is high in the above range.

The (meth) acrylate-containing monomer may include an alkyl (meth) acrylate having 1 to 10 carbon atoms and a monomer copolymerizable therewith.

In one embodiment, the (meth) acrylate-containing monomer may include 50 to 100% by weight of an alkyl (meth) acrylate having 1 to 10 carbon atoms and 0 to 50% by weight of a copolymerizable monomer. Preferably 60 to 100% by weight of an alkyl (meth) acrylate having 1 to 10 carbon atoms and 0 to 40% by weight of a copolymerizable monomer. The dispersibility in the above range is excellent.

Examples of the alkyl (meth) acrylate having 1 to 10 carbon atoms include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl acrylate, isobutyl acrylate, Hexyl (meth) acrylate, isooctyl (meth) acrylate, and the like. Of these, methyl (meth) acrylate is preferable.

The copolymerizable monomer may be at least one monomer selected from the group consisting of styrene, p-methylstyrene, m-methylstyrene, p-ethylstyrene, m-ethylstyrene, p-chlorostyrene, m-chlorostyrene, p-chloromethylstyrene, Aromatic vinyl-based monomers including toluene and vinylnaphthalene; Vinyl cyanide monomers including acrylonitrile and methacrylonitrile; (Meth) acrylate, 2-phenylethyl (meth) acrylate, 3-phenylpropyl (meth) acrylate, 4-phenylbutyl (Meth) acrylate having 6 to 20 carbon atoms such as methyl (meth) acrylate, 2-methylphenyl ethyl (meth) acrylate and 2-4-methylphenyl ethyl (meth) acrylate; (Meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (Meth) acrylate containing an epoxy group such as glycidyl acrylate or glycidyl methacrylate such as (meth) acrylate, 1,4-cyclohexanedimethanol mono (meth) acrylate, ) Acrylate, unsaturated carboxylic acids such as acrylic acid, acrylic acid and methacrylic acid, and the like, but are not limited thereto. The copolymerizable monomers may be used alone or in admixture of two or more.

In a preferred embodiment, the acrylic fine particles contain at least 90% by weight of methyl methacrylate as a monomer component. The refractive index (1.35 to 1.55) as a diffusing agent can be maintained within the above range while maintaining the performance of the container at the same time.

In one embodiment of the present invention, the crosslinking agent may be used alone as the first crosslinking agent.

In another embodiment, the first crosslinking agent and the second crosslinking agent may be mixed and applied.

In an embodiment, the crosslinking agent may include 60 to 100% by weight of the first crosslinking agent and 0 to 40% by weight of the second crosslinking agent. In this range, excellent solvent resistance and excellent polymerization stability are obtained. Preferably, the crosslinking agent may include 65 to 95% by weight of the first crosslinking agent and 5 to 35% by weight of the second crosslinking agent.

When the first crosslinking agent and the second crosslinking agent are mixed and applied, the weight ratio of the first crosslinking agent to the second crosslinking agent may be 1.5 to 10: 1, preferably 2 to 8: 1. The solvent resistance and the dispersibility are both excellent at the above weight ratio.

The first crosslinking agent contains three or more (meth) acrylic groups and contains at least one functional group selected from -OH and -COOH.

In one embodiment, the first crosslinking agent may be represented by the following formula (1):

[Chemical Formula 1]

(Y) _i -R- (Q) _j

Wherein R is a branched hydrocarbon having 1 to 10 carbon atoms, Q is -OH or -COOH, i is an integer of 3 to 5, and j is an integer of 1 to 5, wherein Y is a (meth) acrylic group, Lt; / RTI >

Examples of the first crosslinking agent include pentaerythritol triacrylate, dipentaerythritol pentaacrylate, and the like. These may be used alone or in combination of two or more. Of these, pentaerythritol triacrylate is preferred.

Examples of the second crosslinking agent include 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, ethylene glycol di (Meth) acrylate, trimethylolpropane tri (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, and the like can be used . Of these, 1,6-hexanediol di (meth) acrylate and trimethylolpropane tri (meth) acrylate are preferred.

The acrylic fine particles of the present invention can be produced by polymerization by a conventional method. For example, bulk polymerization, solution polymerization, emulsion polymerization, suspension polymerization and the like can be used, and suspension polymerization is preferred.

In one embodiment, a crosslinking agent may be mixed with a monomer containing (meth) acrylate, a polymerization initiator may be added, and then a suspension stabilizer may be added to polymerize. The polymerization temperature may be 30 to 120 ° C, preferably 50 to 90 ° C.

The polymerization initiator may be selected from the group consisting of benzoyl peroxide, lauryl peroxide, o-chlorobenzoyl peroxide, o-methoxybenzoyl peroxide, t-butyl peroxy-2-ethylhexanoate, t-butyl peroxyisobutyrate, Based compounds such as 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate, dioctanoyl peroxide, and dideckanoyl peroxide, and 2,2'-azobis Azo compounds such as 2,2'-azobis (2-methylbutyronitrile), 2,2'-azobis (2-methylbutyronitrile) and 2,2'-azobis May be used, but are not necessarily limited thereto. The polymerization initiator may be used in an amount of 0.1 to 20 parts by weight based on 100 parts by weight of the mixture of the monomer and the crosslinking agent.

Examples of the suspension stabilizer include gelatin, starch, methylcellulose, ethylcellulose, hydroxyethylcellulose, carboxymethylcellulose, polyvinylpyrrolidone, polyvinylalkylether, polyvinylalcohol, polyacrylic acid, polyacrylamide, polyethylene oxide, Water-soluble polymers such as polymethylsiloxane / polystyrene block copolymer, barium sulfate, calcium lactate, calcium carbonate, calcium phosphate, aluminum sulfate, talc, clay, diatomaceous earth, and metal oxide powder. But is not limited to.

The acrylic fine particles prepared as described above have an average particle size of 1 to 50 μm, preferably 10 to 30 μm, a dispersion index (CV) of 20 to 60%, preferably 30 to 60% Preferably in the range of 40 to 60%.

In an embodiment, the acrylic fine particles may have a swelling degree of less than 10%, preferably less than 5%, and most preferably less than 1% after 4 hours at 25 ° C in methyl ethyl ketone.

Another aspect of the present invention relates to a diffusion film comprising the acrylic fine particles.

The diffusion film may be prepared by injecting the acrylic fine particles into a transparent thermoplastic resin. In the specific example, the acrylic fine particles may be added in an amount of 0.1 to 50 parts by weight, preferably 10 to 35 parts by weight, based on 100 parts by weight of the transparent thermoplastic resin.

Examples of the transparent thermoplastic resin include (meth) acrylic resins, polycarbonate resins, polyester resins, aromatic vinyl resins, and the like, but are not limited thereto.

The diffusion film to which the acrylic fine particles of the present invention are applied as a diffusion agent has excellent diffusibility and permeability.

Hereinafter, the configuration and operation of the present invention will be described in more detail with reference to preferred embodiments of the present invention. It is to be understood, however, that the same is by way of illustration and example only and is not to be construed in a limiting sense.

The contents not described here are sufficiently technically inferior to those skilled in the art, and a description thereof will be omitted.

Example

Examples 1 to 2 and Comparative Examples 1 to 3: Production of acrylic fine particles

Example 1

70 parts by weight of methyl methacrylate (MMA), 20 parts by weight of pentaerythritol triacrylate as a first crosslinking agent, and 10 parts by weight of trimethylolpropane triacrylate (TMPTA) as a second crosslinking agent. To this was added 1 part by weight of benzoyl peroxide (BPO) as a polymerization initiator to prepare a monomer mixture solution. To prepare a suspension, 0.5% by weight of polyvinyl alcohol (PVA) as a suspension stabilizer was dissolved in ionized water as a dispersion medium. The monomer mixture solution was then added to the suspension and homogenized at 8000 rpm for 5 minutes using a homogenizer An emulsion was prepared. Thereafter, the reaction was carried out at 65 ° C for 6 hours in a four-necked flask reactor under a nitrogen atmosphere, and the temperature was raised to 75 ° C to carry out the polymerization reaction for 4 hours. The polymer synthesized by the above reaction was filtered, washed with water and an aqueous ethanol solution, and the filtrate was placed in a vacuum oven for one day to prepare white odorless spherical polymer powder. SEM photographs were used to evaluate the solvent dispersibility of the prepared acrylic fine particles, and they are shown in FIG.

Example 2

The procedure of Example 1 was repeated, except that 30 parts by weight of pentaerythritol triacrylate, which is the first crosslinking agent, was added without using the second crosslinking agent. SEM photographs were used to evaluate the dispersibility of the prepared acrylic fine particles, and they are shown in FIG.

Comparative Example 1

The procedure of Example 1 was repeated except that 30 parts by weight of ethylene glycol di (meth) acrylate (EGDMA) alone was used as a crosslinking agent. SEM photographs were used to evaluate the solvent dispersibility of the acrylic fine particles prepared, and FIG. 3 shows the results.

Comparative Example 2

The procedure of Example 1 was repeated except that 1,6-hexanediol di (meth) acrylate (HDDA) was used instead of pentaerythritol triacrylate as the first crosslinking agent. SEM photographs were used to evaluate the dispersibility of the prepared acrylic fine particles, and FIG. 4 shows the results.

Comparative Example 3

The procedure of Example 1 was repeated except that 30 parts by weight of 1,6-hexanediol di (meth) acrylate (HDDA) alone was used as a crosslinking agent. SEM photographs were used to evaluate the solvent dispersibility of the acrylic fine particles prepared, and the results are shown in FIG.

Comparative Example 4

The procedure of Example 2 was repeated except that 5 parts by weight of pentaerythritol triacrylate was used as the first crosslinking agent.

Property evaluation method

1) Solvent resistance: 15 g of methyl ethyl ketone and 2 g of acrylic fine particles were added to a 20-mL vial and allowed to stand for 4 hours. The swelling ratio was measured as follows.

2) Solvent Dispersibility: 1 g of the acrylic fine particles was mixed with 10 g of ethanol, stirred for 10 minutes, dropped on a slide glass, and analyzed by SEM to evaluate dispersibility, which are shown in FIGS. 1 to 5, respectively. The samples of Example 1 and Comparative Example 1 were measured with an optical microscope (Olympus BX51) at a magnification of 50 and are shown in Fig.

3) Particle Size Dispersion Index (CV): A solution of 18 g of water, 0.5 g of acrylic fine particles and 3 g of dispersion (ethanol: toluene = 5: 5) was put into a vial bottle for 10 minutes in an ultrasonic machine. Then, LS 13 320 of Beckman coulter , The RI (refractive index) = 1.49, and the value of the particle diameter variation coefficient was calculated according to the following equation 1 after measurement at 25 캜.

[Formula 1]

Where M is the volume average size of the particles and? Is the standard deviation.

4) Appearance of coating film: 25 parts by weight of the prepared fine particles, 30 parts by weight of MEK, 15 parts by weight of toluene, and 30 parts by weight of AA-910T of Acrylic Binder Ace Kogyo Co. were mixed and allowed to stand for one day to prepare a coating solution. The mixed coating solution was coated on PET film using # 10 Bar and dried at 120 ° C for 1 minute to prepare a coating film sample. The coating film samples were cut to a size of 5 * 5 cm for evaluating the appearance of the coating film, and the appearance of the coating films was evaluated by an optical microscope.

Item Example 1 Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Monomer 70 70 70 70 70 95 Cross-linking agent PETA 20 30 - - - 5 TMPTA 10 - - 10 - - EGDMA - - 30 - - - HDDA - - - 20 30 - Mean size [Mu m] 15.2 15.8 15.0 15.2 15.0 Not measurable C.V. [%] 46 50 50 42 50 Not measurable Coat appearance O.K O.K Slightly
Clustering occurs O.K O.K Clustering occurs Solvent resistance One% 3% 10% 25% 28% 57%

As shown in Table 1 and FIGS. 1 to 5, the acrylic fine particles according to the present invention were found to have excellent coating appearance, solvent resistance and dispersibility. On the other hand, Comparative Example 1 showed that the appearance of the coating was clumped and the solvent resistance was also deteriorated. Also, in Comparative Examples 2 and 3, the outer appearance of the coating film was excellent, but it was confirmed that the solvent resistance was deteriorated. On the other hand, in the case of Comparative Example 4 in which the monomer was excessively applied, it was impossible to measure the average particle diameter and the particle size dispersion index (CV), and it was found that the coating film was clumped and the solvent resistance remarkably decreased.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It will be understood that the invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. It is therefore to be understood that the embodiments described above are in all respects illustrative and not restrictive.

Claims (13)

(Meth) acrylate and 10 to 40% by weight of a crosslinking agent, wherein the crosslinking agent contains at least three (meth) acrylic groups and at least one of -OH and -COOH Wherein the acryl-based fine particles have a dispersion index (CV) of 20 to 60% and an average particle size of 1 to 50 탆.
The acrylic fine particle according to claim 1, wherein the acrylic fine particles have a dispersion index (CV) of 40 to 60%.
The acrylic fine particle according to claim 1, wherein the first cross-linking agent is represented by the following formula (1):
[Chemical Formula 1]
(Y) _i- R- (Q) _j
Wherein R is a branched hydrocarbon having 1 to 10 carbon atoms, Q is -OH or -COOH, i is an integer of 3 to 5, and j is an integer of 1 to 5, wherein Y is a (meth) acrylic group, Lt; / RTI >
The acrylic fine particle according to claim 1, wherein the acrylic fine particles comprise 60 to 85% by weight of a monomer containing (meth) acrylate and 15 to 40% by weight of a crosslinking agent.
The acrylic fine particle according to claim 1, wherein the (meth) acrylate-containing monomer comprises an alkyl (meth) acrylate having 1 to 10 carbon atoms and a monomer copolymerizable therewith.
[7] The method according to claim 5, wherein the monomer containing (meth) acrylate comprises 50 to 100% by weight of alkyl (meth) acrylate having 1 to 10 carbon atoms and 0 to 50% Fine particles.
6. The composition of claim 5, wherein the copolymerizable monomer is selected from the group consisting of an aromatic vinyl monomer, a vinyl cyanide monomer, an aromatic (meth) acrylate having 6 to 20 carbon atoms, a hydroxyl group-containing (meth) acrylate, , And an unsaturated carboxylic acid.
The positive resist composition according to claim 1, wherein the crosslinking agent is selected from the group consisting of 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, (Meth) acrylate, trimethylolpropane tri (meth) acrylate, and ditrimethylol propane tetra (meth) acrylate, and the like. Lt; RTI ID = 0.0 > a < / RTI > second cross-linking agent.
The acrylic fine particle according to claim 8, wherein the crosslinking agent comprises 60 to 100% by weight of the first crosslinking agent and 0 to 40% by weight of the second crosslinking agent.
The acrylic fine particle according to claim 9, wherein the weight ratio of the first crosslinking agent to the second crosslinking agent is 1.5 to 10: 1.
The acrylic fine particle according to claim 1, wherein the acrylic fine particles have a swelling degree of less than 10% after 4 hours at 25 DEG C in methyl ethyl ketone.
11. A diffusion film comprising the acrylic fine particles according to any one of claims 1 to 11.
60 to 90% by weight of a monomer containing (meth) acrylate and 10 to 40% by weight of a crosslinking agent are mixed and an initiator is mixed to prepare a monomer mixture solution; And
Subjecting the monomer mixture solution to suspension polymerization;
And having a dispersion index (CV) of 20 to 60% and an average particle size of 1 to 50 占 퐉,
Wherein the cross-linking agent comprises a first cross-linking agent containing at least three (meth) acrylic groups and at least one functional group selected from the group consisting of -OH and -COOH.

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