KR101918623B1 - Adhesive composition and complexed polarization plate using the same - Google Patents

Abstract

The present invention relates to an adhesive composition, and more particularly, it relates to an adhesive composition comprising a styrene-based monomer having a hydroxy group and a polymerized binder resin and a cross-linking agent to thereby form a composite polarizer , An adhesive composition which remarkably improves a bonding force between a polarizer and a patterned retardation layer, improves heat resistance and heat and humidity resistance, and has an excellent 3D stereoscopic effect.

Description

TECHNICAL FIELD [0001] The present invention relates to an adhesive composition and a composite polarizer using the adhesive composition.

The present invention relates to an adhesive composition and a composite polarizer using the same

In a display such as a liquid crystal display for stereoscopic image implementation, a patterned retardation film is often included. The patterned retardation film realizes a stereoscopic image by configuring the optical axes of the respective pattern regions in different directions so that images transmitted to the left and right eyes of the viewer wearing polarized glasses are different.

The patterned retardation film can be usually formed by forming an alignment film on a glass substrate and coating and orienting a liquid crystal on the alignment film. The photoreactive liquid crystal material is oriented on the alignment layer and then crosslinked by light irradiation such as ultraviolet rays to form a polymer liquid crystal film. At this time, the retarder pattern functions in accordance with the alignment direction of the liquid crystal in accordance with the surface orientation of the alignment film.

The patterned retardation film is usually bonded to one side of a polarizing plate via an adhesive or a pressure-sensitive adhesive, and is recently bonded to one side of a polyvinyl alcohol polarizer for further thin film lightening.

If the patterned retardation film is inferior in adhesion between the polarizing plate and the polarizer, deformation may occur during handling or during use in the process, and peeling or bumping may occur when the film is exposed to high temperature and high humidity for a long time. In addition, a conventional polyvinyl alcohol polarizer can shrink in the stretching direction, so that the retardation differs depending on the position of the retardation layer, and the 3D stereoscopic effect may be lowered.

Accordingly, there is a demand for development of an excellent adhesive having excellent bonding strength, excellent functions such as resistance to water temperature and resistance to humidity, and the like.

Korean Patent Laid-Open Publication No. 2013-0028881 discloses a method for producing a film pattern reliader and a film pattern reliator, and a polarizing plate and an image display device having the film pattern reliator.

Korea Patent Publication No. 2013-0028881

An object of the present invention is to provide an adhesive composition capable of remarkably improving the bonding force between a polarizer and a patterned retardation layer when used for producing a composite polarizer plate by bonding a polarizer and a patterned retardation layer.

It is an object of the present invention to provide a composite polarizing plate bonded through the above adhesive composition.

1. An adhesive composition comprising a polymerized binder resin comprising a styrene-based monomer having a hydroxy group and a crosslinking agent.

2. The adhesive composition according to 1 above, wherein the styrene-based monomer having a hydroxy group is represented by the following formula (1)

[Chemical Formula 1]

(Wherein R ₁ is a hydrogen atom or a methyl group,

R ₂ is a direct bond, a linear or branched alkylene group having 1 to 6 carbon atoms, -CO- or -SO ₂ -

Wherein the alkylene group may be interrupted by an oxygen atom.

3. The adhesive composition according to 1 above, wherein the styrene-based monomer having a hydroxy group is polymerized in an amount of 50% by weight or more based on the total weight of all the monomers.

4. The adhesive composition according to 1 above, wherein the binder resin is further polymerized to include an ionic monomer.

5. The adhesive composition according to 4 above, wherein the ionic monomer is at least one selected from the group consisting of an acryl-based ammonium salt, a styrenic ammonium salt, and a vinyl-based imidazolinium salt.

6. The adhesive composition according to 4 above, wherein the ionic monomer is polymerized in an amount of 7 to 30% by weight based on the total weight of the total monomers.

7. The adhesive composition according to 1 above, wherein the binder resin is polymerized by further comprising at least one of an acrylic monomer having a hydroxyl group and an acrylic monomer having a carboxyl group.

8. The adhesive composition according to 7 above, wherein the acrylic monomer having a hydroxyl group and the acrylic monomer having a carboxyl group are polymerized so that the total content thereof is 7 to 30% by weight of the total weight of the total monomers.

9. The method of claim 1, wherein the crosslinking agent is selected from the group consisting of monoaldehydes, dialdehydes, amino-formaldehyde resins, glyoxalates, acetal compounds, divalent metals, divalent metal salts, trivalent metals, Wherein the adhesive composition is at least one selected from the group consisting of polyamides, polyamides, polyamides, polyamides, polyamides, polyamides, polyamides, polyamides, polyamides and polyamides.

10. Polarizer, and

And a patterned retardation layer bonded to one surface of the polarizer through the adhesive composition of any one of [1] to [9] above.

11. The composite polarizer of claim 10, wherein the polarizer is formed by bonding a protective film or a film having the function of a retardation film to the opposite surface of the surface bonded with the patterned retardation layer.

12. The composite polarizer of claim 10, wherein the patterned retardation layer comprises a liquid crystal coating layer containing a reactive liquid crystal monomer comprising a benzene ring.

13. The composite polarizer of claim 10, wherein the patterned retardation layer does not comprise an alignment film.

14. The composite polarizer of claim 10, wherein the peel strength between the polarizer and the patterned retardation layer is 1.0 N / 25 mm or greater.

15. An image display device comprising the composite polarizer plate of the above 10.

The pressure-sensitive adhesive composition of the present invention remarkably improves the bonding force between the polarizer and the patterned retardation layer when the polarizer and the patterned retardation layer are bonded to produce a composite polarizing plate.

The composite polarizer laminated with the pressure-sensitive adhesive composition of the present invention is excellent in heat resistance and heat and humidity resistance, and peeling and bending phenomenon are suppressed even when exposed to high temperature and high humidity conditions for a long time.

The composite polarizing plate bonded with the pressure-sensitive adhesive composition of the present invention has a polarization function and an improved 3D stereoscopic effect at the same time.

The present invention relates to a process for producing a composite polarizing plate, which comprises a styrene-based monomer having a hydroxyl group, and comprises a polymerized binder resin and a crosslinking agent so that when a polarizer and a patterned retardation layer are bonded to form a composite polarizing plate, The present invention relates to an adhesive composition capable of remarkably improving the bonding force, improving the heat resistance and the heat and humidity resistance, and having an excellent 3D stereoscopic effect.

Hereinafter, the present invention will be described in detail.

Adhesive composition

The adhesive composition of the present invention is an aqueous adhesive composition comprising a binder resin.

The binder resin according to the present invention includes a styrene-based monomer having a hydroxyl group.

The adhesive composition of the present invention has excellent bonding strength when used for bonding a polarizer and a patterned retardation layer, and the heat resistance and the resistance to moisture and humidity are also improved by such bonding strength improvement. The styrene monomer according to the present invention comprises a hydroxyl group, which is hydrogen bonded to a polar group contained in the liquid crystal coating layer of the polarizer surface polarizer and the patterned retardation layer, and the benzene ring of the styrene monomer has a patterned retardation Bonding interaction with the benzene ring contained in the liquid crystal coating layer of the layer.

The styrene-based monomer having a hydroxyl group according to the present invention is not particularly limited, and examples thereof include monomers represented by the following formula (1)

[Chemical Formula 1]

(Wherein R ₁ is a hydrogen atom or a methyl group,

R ₂ is a direct bond, a linear or branched alkylene group having 1 to 6 carbon atoms, -CO- or -SO ₂ -

Wherein the alkylene group may be interrupted by an oxygen atom.

Specific examples of the styrene-based monomer having a hydroxyl group include the following formulas (a-1) to (a-5), which may be used alone or as a mixture of two or more thereof. The monomer of formula (a-4) has a carboxyl group, but has -OH, and R ₂ is -CO- in formula (1) In which R ₂ is -SO ₂ -, all of which are in the range of the above formula (1), and thus are interpreted as being included in the styrene-based monomer having the hydroxyl group of the present invention.

[Formula a-1]

[Formula a-2]

[Formula a-3]

[Formula a-4]

[Formula a-5]

The content of the styrene-based monomer having a hydroxyl group is not particularly limited within a range capable of performing the above function, and may be polymerized in an amount of, for example, 50% by weight or more based on the total weight of all monomers. When the content is within the above range, the bonding force between the polarizer and the patterned retardation layer can be maximized. In this respect, it may preferably comprise from 50 to 85% by weight of the total weight of the total monomers.

The binder resin according to the present invention can be polymerized by further containing an ionic monomer. In such a case, the solubility in the solvent is remarkably improved, so that the bonding force is improved, and the occurrence of the poor viscous defect caused by the residual foreign matter can be suppressed.

The ionic monomer according to the present invention is not particularly limited as long as it can perform the functions described above, and examples thereof include acrylic ammonium salt, styrene-based ammonium salt, and vinyl imidazolium salt. Specifically, monomers represented by the following formulas (2) to (6) are exemplified. These may be used alone or in combination of two or more.

(2)

(3)

[Chemical Formula 4]

[Chemical Formula 5]

[Chemical Formula 6]

The content of the ionic monomer is not particularly limited within the range capable of performing the above functions, and may be polymerized in an amount of, for example, 7 to 30% by weight based on the total weight of all the monomers. When the content of the ionic monomer is less than 7% by weight, the solubility improvement effect may be insignificant. When the content is more than 30% by weight, the heat and humidity resistance and adhesion may be lowered.

The molecular weight of the binder resin is not particularly limited, and for example, the weight average molecular weight may be 5,000 to 100,000.

The binder resin may be prepared by a conventional polymerization method, and the weight average molecular weight may be controlled by changing conditions such as the content of the initiator, the reaction temperature, the reaction time, the type and content of the catalyst, and the use of other components. The kind of the solvent and the polymerization initiator is not particularly limited, and those known in the art can be used.

If necessary, the binder resin according to the present invention may further comprise at least one of an acrylic monomer having a hydroxyl group and an acrylic monomer having a carboxyl group. By further polymerizing an acrylic monomer having a hydroxyl group or a carboxyl group, the wettability of the resin can be improved and the bonding force can be further improved.

The acrylic monomer having a hydroxyl group according to the present invention may be represented by the following general formula (7)

(7)

Wherein R ₁ is hydrogen or a methyl group, X is oxygen or -NH-, R ₂ is a straight or branched chain alkylene group having 1 to 6 carbon atoms, and is interrupted by a cycloalkylene group having 3 to 6 carbon atoms Lt; / RTI >

Specific examples of the acrylic monomer having a hydroxyl group according to the present invention include the following formulas (b-1) to (b-6), which may be used alone or as a mixture of two or more thereof.

[Formula b-1]

[Formula b-2]

[Formula b-3]

[Formula b-4]

[Formula b-5]

[Formula b-6]

Specific examples of the acrylic monomer having a carboxyl group according to the present invention include the following formulas c-1 to c-9, which may be used alone or in combination of two or more.

[Formula c-1]

[Formula c-2]

[Formula c-3]

[Formula c-4]

[Formula c-5]

[Formula c-6]

[Formula c-7]

[Chemical formula c-8]

[Chemical formula c-9]

The acrylic monomer having a hydroxyl group and the acrylic monomer having a carboxyl group may be polymerized so that the total content thereof is 7 to 30% by weight of the total weight of the total monomers. If the total content is less than 7% by weight, the effect of improving the wettability may be insignificant. If the total content is more than 30% by weight, the interaction with the patterned retardation layer may be decreased and the bonding strength may be lowered.

The adhesive composition of the present invention further comprises a crosslinking agent.

The cross-linking agent is not particularly limited, and a cross-linking agent commonly used in the art can be used. Examples of the aldehyde include monoaldehydes such as formaldehyde, acetaldehyde, propionaldehyde and butylaldehyde; dialdehydes such as glyoxal, malondialdehyde, succindialdehyde, glutarialdehyde, maleindialdehyde and phthalaldehyde; An amino-formaldehyde resin such as methylol urea, methylol melamine, alkylated methylol urea, alkylated methylol melamine, acetoguanamine, condensates of benzoguanamine and formaldehyde; glyoxylic acid metal salts For example, alkali metals such as lithium, sodium and potassium, alkaline earth metals such as magnesium and calcium, transition metals such as titanium, zirconium, chromium, manganese, iron, cobalt, nickel and copper, zinc and aluminum) Glyoxylic acid salts such as glyoxylic acid amine salts (examples of the amine include ammonia, monomethylamine, dimethylamine, trimethylamine and the like); Divalent metal or a salt of magnesium, calcium, aluminum, iron, nickel, zinc, and the like; methoxy bullet, diethoxy bullet, bullet-dialkoxy acetal such as the compound of the; A trivalent metal; A tetravalent metal; Metal chelating compounds; Oxazolines; Melamine; Aziridines; And polyvalent inorganic acids such as boric acid, phosphoric acid, and sulfuric acid. These may be used alone or in combination of two or more.

The content of the crosslinking agent is not particularly limited and may be, for example, 0.5 to 20 parts by weight based on 100 parts by weight of the binder resin. When the content of the crosslinking agent is within the above range, the effect of improving the bonding force between the polarizer and the patterned retardation layer is excellent.

<Composite Polarizer>

The present invention also provides a composite polarizing plate produced using the adhesive composition.

The composite polarizing plate of the present invention comprises a polarizer and a patterned retardation layer bonded to one surface of the polarizer through the adhesive composition.

In the composite polarizing plate of the present invention, the polarizer and the patterned retardation layer are bonded to each other through the adhesive composition, and the bonding strength is excellent. In this case, as described above, the adhesive composition layer forms a hydrogen bond with the polarizer, forms a hydrogen bond with the patterned retardation layer, and a pi bond interaction can be generated.

Polarizers are generally used in the display field and are not limited to specific ones as long as they can polarize incident light. For example, a film made of polyvinyl alcohol (PVA) may be prepared by dyeing iodine or a dichroic dye and stretching it in a predetermined direction. And a protective film or a film having a function of a retardation film may be bonded to a surface opposite to the surface bonded with the patterned retardation layer.

The structure of the patterned retardation layer is not particularly limited, and may include a structure commonly used in the art. For example, it may have a structure in which a substrate, an alignment film, and a liquid crystal coating layer are laminated in this order, or may be a structure that does not include an alignment film.

The patterned retardation layer is bonded so that the liquid crystal coating layer faces the polarizer.

The base material is not particularly limited as long as it is formed of a material excellent in transparency, mechanical strength, thermal stability, water shielding property, phase difference uniformity, isotropy, etc. For example, a polyolefin resin, a polyester resin, a cellulose resin, , An acrylic resin, a styrene resin, a vinyl chloride resin, an amide resin, an imide resin, a polyether sulfone resin, a sulfone resin, a polyether sulfone resin, a polyetheretherketone resin, A substrate formed of at least one material selected from the group consisting of a vinyl alcohol resin, a vinylidene chloride resin, a vinyl butyral resin, an allylate resin, a polyoxymethylene resin and an epoxy resin can be used.

When the patterned retardation layer comprises an alignment film, the alignment film is formed by a method of coating on a substrate a composition for forming an alignment film commonly used in the art, imparting orientation, and then patterning the film so as to have different orientation directions .

The orientation imparting method includes a rubbing method, a photo alignment method, and the like. The patterning method can be performed by a plurality of exposure steps using a photomask, but the present invention is not limited thereto.

The light used for exposure is not particularly limited, and for example, polarized ultraviolet radiation, ion beam or plasma beam irradiation at a predetermined angle, and irradiation with radiation may be used. It is preferable to irradiate polarized ultraviolet rays, for example.

The liquid crystal coating layer may be formed by applying a composition for forming a liquid crystal coating layer containing a reactive liquid crystal monomer (RM) or the like commonly used in the art on an alignment film and crosslinking.

The reactive liquid crystal monomer is not particularly limited and monomers conventionally used in the art may be used, but it may preferably be a monomer having a benzene ring.

In the case where the patterned retardation layer does not include an alignment film, a composition for forming a liquid crystal coating layer may be applied on a substrate without an alignment film, and the alignment and patterning may be simultaneously performed to form a patterned retardation layer.

In this case, the composition for forming a liquid crystal coating layer may further contain a compound capable of alignment by polarized ultraviolet light such as a linear photopolymerizable polymer for orientation.

When the patterned retardation layer does not include an alignment film, a thinner display can be realized.

The composite polarizing plate of the present invention prepared using the above adhesive composition has excellent bonding strength between the polarizer and the patterned retardation layer. For example, the peeling force between the polarizer and the patterned retardation layer may be 1.0 N / 25 mm or more, preferably 1.0 to 3.0 N / 25 mm Or more.

<Image Display Device>

Further, the present invention provides an image display apparatus including the composite polarizer.

The image display device is not particularly limited and includes, for example, a stereoscopic image implementing or semi-transmission type liquid crystal display device, a plasma display device, and an organic EL display device.

The complex polarizing plate of the present invention can be used at a position where a conventional polarizing plate and a patterned retardation layer are laminated.

It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to be illustrative of the invention and are not intended to limit the scope of the claims. It will be apparent to those skilled in the art that such variations and modifications are within the scope of the appended claims.

Example  And Comparative Example

An adhesive composition having the composition and contents shown in the following Table 1 was prepared. In the case of the binder resin, the weight average molecular weight was 10,000 g / mol.

division Binder resin Cross-linking agent
(E) A styrene-based monomer having a hydroxy group
(A) Ionic monomer
(B) An acrylic monomer having a hydroxyl group or a carboxyl group
(C) Other Monomers
(D) ingredient Weight portion ingredient Weight portion ingredient Weight portion ingredient Weight portion ingredient Weight portion Example 1 A-1 100 - - - - - - E-1 One Example 2 A-2 100 - - - - - - E-1 One Example 3 A-3 100 - - - - - - E-2 One Example 4 A-4 100 - - - - - - E-2 One Example 5 A-1 75 B-1 25 - - - - E-1 One Example 6 A-1 75 B-2 25 - - - - E-2 One Example 7 A-1 75 B-3 25 - - - - E-3 One Example 8 A-1 88 B-1 12 - - - - E-1 One Example 9 A-1 85 B-1 15 - - - - E-1 One Example 10 A-1 50 B-1 25 C-1 25 - - E-1 One Example 11 A-1 47 B-1 27 C-1 26 - - E-1 One Example 12 A-1 70 B-1 15 C-2 15 - - E-3 One Example 13 A-1 60 B-1 32 C-2 8 - - E-3 One Example 14 A-1 60 B-1 8 C-2 32 - - E-3 One Example 15 A-1 85 B-1 10 C-1 5 - - E-1 One Example 16 A-1 85 B-1 5 C-1 10 - - E-1 One Example 17 A-1 75 - - C-1 25 - - E-1 One Comparative Example 1 - - B-1 50 C-1 50 - - E-1 One Comparative Example 2 - - B-2 100 - - - - E-2 One Comparative Example 3 - - - - C-1 100 - - E-1 One Comparative Example 4 - - - - C-2 90 D-1 10 E-1 One Comparative Example 5 - - - - C-3 50 D-2 50 E-2 One Comparative Example 6 B-1 30 C-1 30 D-2 40 E-3 One Comparative Example 7 - - B-2 50 - - D-3 50 E-2 One Comparative Example 8 - - - - - - D-4 100 E-1 One

A-2:

A-3:

A-4:

B-1:

B-2:

B-3:

C-1:

C-2:

C-3:

D-1: 트리메틸올프로판 트리아크릴레이트 D-2:

D-3:

D-4:

E-1: 글리옥살 E-2: 붕산
E-3: ZnCl₂ A-1:

A-2:

A-3:

A-4:

B-1:

B-2:

B-3:

C-1:

C-2:

C-3:

D-1: trimethylolpropane triacrylate D-2:

D-3:

D-4:

E-1: Glyoxal E-2: Boric acid
E-3: ZnCl ₂

Experimental Example

(One) Peel force  Measure

A polyvinyl alcohol polarizer in which a patterned retardation layer (MPR32, DNP yarn) and a triacetyl cellulose protective film were bonded to one side was made to contact the liquid crystal coating layer and the polarizer, and the adhesive compositions of Examples and Comparative Examples were laminated using a roll laminator Respectively. For the evaluation, the end portion was not coated with the adhesive.

Thereafter, it was dried at 100 DEG C for 3 minutes and allowed to stand at room temperature for 48 hours to be cured.

The peeling force was measured by cutting the prepared composite polarizing plate sample to a width of 25 mm and peeling at a rate of 300 mm / min in a 180 degree peeling direction.

(2) heat resistance, Humidity Durability  evaluation

A composite polarizing plate was prepared in the same manner as in Experimental Example (1), and an acrylic pressure-sensitive adhesive was coated and cured on the protective film, and then bonded to soda glass and autoclaved.

Then, the heat resistance and the heat and humidity resistance of each of the composite polarizers were tested.

The heat resistance test was carried out at 80 ° C for 500 hours and the humidity and humidity test was conducted at 60 ° C and 90% RH for 500 hours. After that, bubbles or peeling occurred on the bonding surface between the liquid crystal coating layer and the polarizer, And the resistance to humidity was evaluated.

◎: No bubbles or peeling at all

○: There are bubbles or peeling, but only in very small areas.

Δ: Bubbles or peeling were confirmed somewhat

X: Bubbles or peeling can easily be confirmed visually over a significant area

division Peel force (N / 25mm) Heat resistance Humidity Durability Example 1 1.5 ○ ◎ Example 2 1.3 ○ ◎ Example 3 1.7 ○ ◎ Example 4 1.9 ○ ◎ Example 5 2.2 ◎ ◎ Example 6 2.3 ◎ ◎ Example 7 2.4 ◎ ◎ Example 8 1.8 ○ ◎ Example 9 2.1 ◎ ◎ Example 10 2.5 ◎ ◎ Example 11 2.0 ◎ ◎ Example 12 2.9 ◎ ◎ Example 13 2.3 ◎ ◎ Example 14 2.5 ◎ ○ Example 15 2.2 ◎ ◎ Example 16 2.3 ◎ ○ Example 17 2.2 ◎ ◎ Comparative Example 1 0.8 X △ Comparative Example 2 0.6 X X Comparative Example 3 0.5 X △ Comparative Example 4 0.7 X X Comparative Example 5 0.3 X X Comparative Example 6 0.5 X X Comparative Example 7 0.9 △ X Comparative Example 8 0.2 X X

Referring to Table 2, it was confirmed that the composite polarizing plates of Examples 1 to 17 were excellent in peel strength, excellent in heat resistance and heat and humidity resistance, and excellent in durability.

However, in the composite polarizing plates of Comparative Examples 1 to 8, the peeling force was significantly lowered, and a large number of bubbles and peeling occurred in evaluation of heat resistance and resistance to heat and humidity, and durability was remarkably low.

Claims (15)

From 7 to 30% by weight of at least one monomer selected from the group consisting of an acrylic monomer having a hydroxyl group and an acrylic monomer having a carboxyl group, in an amount of 50 to 85% by weight of a styrene monomer having a hydroxyl group in the total weight of all monomers, 7 to 30% A polymerized binder resin; And a crosslinking agent.
The adhesive composition according to claim 1, wherein the styrene-based monomer having a hydroxy group is represented by the following formula (1)
[Chemical Formula 1]

(Wherein R ₁ is a hydrogen atom or a methyl group,
R ₂ is a direct bond, a linear or branched alkylene group having 1 to 6 carbon atoms, -CO- or -SO ₂ -
Wherein the alkylene group may be interrupted by an oxygen atom.
delete delete The adhesive composition according to claim 1, wherein the ionic monomer is at least one selected from the group consisting of an acryl-based ammonium salt, a styrene-based ammonium salt, and a vinyl-based imidazolinium salt.
delete delete delete The method of claim 1, wherein the crosslinking agent is selected from the group consisting of monoaldehydes, dialdehydes, amino-formaldehyde resins, glyoxalates, acetal compounds, divalent metals, divalent metal salts, trivalent metals, tetravalent metals, metal chelate compounds, Wherein the adhesive composition is at least one selected from the group consisting of oxazolines, melamines, aziridines, and polyfunctional inorganic acids.
Polarizer, and
And a patterned retardation layer bonded to one side of the polarizer through the adhesive composition of any one of claims 1, 2, 5 and 9.
[Claim 11] The composite polarizer of claim 10, wherein the polarizer is formed by bonding a protective film or a film having a function of a retardation film to the opposite surface of the surface bonded with the patterned retardation layer.
11. The composite polarizer of claim 10, wherein the patterned retardation layer comprises a liquid crystal coating layer containing a reactive liquid crystal monomer comprising a benzene ring.
The composite polarizer of claim 10, wherein the patterned retardation layer does not comprise an alignment film.
The composite polarizer according to claim 10, wherein the peeling force between the polarizer and the patterned retardation layer is 1.0 N / 25 mm or more.
10. An image display comprising the composite polarizing plate of claim 10.