JP5829034B2 - Photocurable thermosetting composition for inkjet and printed wiring board using the same - Google Patents

Description

  The present invention is a photocurable thermosetting composition used for forming a resin insulating layer, and is suitable for drawing a pattern directly on a substrate for a printed wiring board using an ink jet printer. The present invention relates to a thermosetting composition and a printed wiring board having a resin insulating layer formed using the same.

  As a method for producing a printed wiring board using an ink jet printer, for example, there is a method for forming a conductive circuit in which an etching resist is formed on a metal foil on a plastic substrate using an ink jet printer and an etching process is performed (Japanese Patent Laid-Open No. Sho). 56-66089, JP 56-157089, JP 58-50794, JP 6-237063). This method draws the pattern directly on the metal foil according to the CAD data. Compared to patterning by photo development using a photosensitive resin that requires a photomask and patterning resist ink by screen printing. Thus, the labor and time required for the production process of the printed wiring board can be greatly reduced, and at the same time, consumables such as developer, resist ink, and cleaning solvent can be reduced.

  Also, a resin insulating layer such as a solder resist for protecting a conductor circuit formed on a printed wiring board has already been proposed using an ink jet printer (Japanese Patent Laid-Open Nos. 7-263845 and 9-18115). reference). The formation method is the same as the method for forming the etching resist described above. Even when this ink jet method is used, the number of steps, time, and consumables can be reduced as compared with the photographic development method and the screen printing method. Furthermore, the ink tank of the ink jet printer is divided into, for example, an etching resist ink, a solder resist ink, a marking ink, and a curing agent thereof, and the ink jet printer is provided with the ink jet printer, so that a plurality of steps can be performed with one ink jet printer. A method that can be performed has also been proposed (see JP-A-8-236902).

  However, the ink used for the ink jet printer needs to have a viscosity of about 20 mPa · s or less when applied. On the other hand, the viscosity of the ink used for screen printing is around 20,000 mPa · s, and there is a large difference in the viscosity between the two. Therefore, even when the resist ink for screen printing is diluted with a large amount of diluent, it is difficult to reduce it to a viscosity that can be used for an ink jet printer. Even if the viscosity of the resist ink can be reduced to 20 mPa · s, physical properties such as heat resistance and chemical resistance required for a resin insulating layer such as a solder resist are greatly reduced. Furthermore, when the resist ink is diluted with a volatile solvent, the non-volatile content becomes very small, and it becomes difficult to secure a predetermined film thickness when the resist ink is applied to the substrate. Therefore, as a method for forming a resin insulation layer of a printed wiring board, the ink jet method is not out of the idea, and can be used in an ink jet printer, and a resin composition such as a resist ink for forming a practical resin insulation layer. Did not exist.

  The present invention has been made in order to solve the above-described problems of the prior art, and its main purpose is a photocurable thermosetting composition used for forming a resin insulating layer, using an inkjet printer. An object of the present invention is to provide a photocurable thermosetting composition capable of directly drawing a pattern on a substrate for a printed wiring board.

  Still another object of the present invention is to provide a print having a resin insulating layer obtained by directly drawing a pattern on a substrate for a printed wiring board by an ink jet printer using the photocurable thermosetting composition and curing the pattern. It is to provide a wiring board.

JP 56-66089 A JP 56-157089 JP 58-50794 JP-A-6-237063 JP-A-7-263845 JP-A-9-18115 JP-A-8-236902 International Publication WO2004 / 099272

  The problem to be solved by the present invention is a viscosity that can be used in an ink jet printer, which is excellent in heat resistance and chemical resistance required for a resin insulating layer, has good adhesion, and further has a printed wiring board. An object of the present invention is to provide a photocurable thermosetting composition that can be thermally cured at a low temperature of 170 ° C. or lower, preferably 150 ° C. or lower, which is a heating temperature during production.

In order to achieve the above object, the present invention has the following features.
That is, one of the features of the present invention is that a monomer having a (meth) acryloyl group and a glycidyl group in the molecule and having a viscosity at 25 ° C. of 10 mPa · s or less, a trifunctional or higher acrylate monomer, and a thermosetting catalyst And a photopolymerization initiator. A photocurable thermosetting composition for inkjet.

  Another feature of the present invention is that the monomer having a (meth) acryloyl group and a glycidyl group in the molecule and having a viscosity at 25 ° C. of 10 mPa · s or less is glycidyl methacrylate or 4-hydroxybutyl acrylate glycidyl ether. Is a photocurable thermosetting composition for inkjet.

  Still another feature of the present invention is that in the above-described photocurable thermosetting composition for inkjet, a monomer having a (meth) acryloyl group and a glycidyl group in the molecule and having a viscosity at 25 ° C. of 10 mPa · s or less. When it is 100 parts by mass, the trifunctional or higher functional acrylate monomer is 15 to 400 parts by mass, preferably 20 to 300 parts by mass, and the thermosetting catalyst is 0.1 to 5 parts by mass, preferably 0.5 to 4 parts by mass. It is to contain part.

  Here, in this specification, a viscosity refers to the viscosity measured according to JIS K2283. Moreover, the viscosity of the said photocurable thermosetting composition for inkjets is 150 mPa * s or less at normal temperature (25 degreeC). As described above, the viscosity of the ink used in the ink jet printer needs to be about 20 mPa · s or less at the temperature at the time of application. However, if the viscosity is 150 mPa · s or less at room temperature, the above conditions can be satisfied by heating before coating or by heating during coating.

  Furthermore, another feature of the present invention is that it has a resin insulating layer obtained by drawing a pattern on a substrate by an ink jet printer using the photocurable thermosetting composition for ink jet and curing the pattern. Printed wiring board.

  The photocurable thermosetting composition for inkjet according to the present invention comprises a monomer having a (meth) acryloyl group and a glycidyl group in the molecule and a viscosity at 25 ° C. of 10 mPa · s or less, a trifunctional or higher acrylate monomer, By blending, it is possible to improve the heat resistance, chemical resistance, and adhesion of the resin insulation layer obtained by curing this. In particular, in a conventional inkjet resin composition, a photosensitive monomer having a high viscosity (or a photosensitive thermosetting monomer) is used, and the composition is reduced to the predetermined viscosity (20 mPa · s). In general, a monofunctional photosensitive monomer having a low viscosity is blended. On the other hand, in the present invention, by using a monomer having a low viscosity as a photosensitive thermosetting monomer and having a (meth) acryloyl group and a glycidyl group in the molecule and a viscosity at 25 ° C. of 10 mPa · s or less, It is possible to blend a tri- or higher functional acrylate monomer with excellent viscosity, chemical resistance and adhesion.

  In addition, the photocurable thermosetting composition for inkjet according to the present invention is cured at 170 ° C. or lower, preferably 150 ° C. or lower, which is a heating temperature when manufacturing a printed wiring board, by blending a thermosetting catalyst. be able to. Thereby, the resin insulating layer can be formed without affecting the characteristics of the printed wiring board.

  Hereinafter, an embodiment of the present invention will be described in detail. Of course, the present invention is not limited to this embodiment.

As described above, the photocurable thermosetting composition for inkjet according to the present invention can directly draw a predetermined pattern on a substrate for a printed wiring board using an inkjet printer, and an active energy ray can be drawn on the pattern. A resin insulating layer having excellent heat resistance, chemical resistance, adhesion, and the like can be formed by first curing by irradiation and then further heat curing. Moreover, since the said composition contains the thermosetting catalyst, it becomes possible to fully harden | cure even at the low temperature of the heating temperature when manufacturing a printed wiring board in the said heat curing. In this case, irradiation conditions of the active energy ray, 100 mJ / cm ² or more, preferably it is desirable to ^{300mJ / cm 2 ~2000mJ / cm 2} . Further, the heat curing conditions are 140 to 170 ° C. for 20 minutes or longer, preferably 150 to 170 ° C. for 20 to 60 minutes.

  The irradiation of the active energy ray includes a method performed after drawing a pattern by an ink jet printer and a method performed in parallel with the pattern drawing. The latter method is preferable from the viewpoint of shortening time and processes. As a method of performing the irradiation of the active energy rays in parallel with the pattern drawing, for example, there is a method of irradiating the active energy rays from the side portion or the bottom portion of the substrate at the time of pattern drawing. As the irradiation source of the active energy ray, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a xenon lamp, a metal halide lamp, or the like can be used. In addition, electron beams, α rays, β rays, γ rays, X rays, neutron rays and the like can be used.

  Hereinafter, the photocurable thermosetting composition for inkjet according to the present invention will be described.

  Examples of the monomer having a (meth) acryloyl group and a glycidyl group in the molecule and having a viscosity at 25 ° C. of 10 mPa · s or less include glycidyl methacrylate and 4-hydroxybutyl acrylate glycidyl ether. There are NOF Blemmer G and Kyoeisha Chemical Light Ester G. In the present specification, the (meth) acryloyl group is a generic term for an acryloyl group and a methacryloyl group, and the same applies to other similar expressions.

  Examples of the tri- or higher functional acrylate monomer include polyethylene glycol diacrylates such as triethylene glycol diacrylate and tetraethylene glycol diacrylate, pentaerythritol triacrylate, trimethylolpropane triacrylate, trimethylolmethane triacrylate, and ethylene oxide-modified trimethylolpropane. Triacrylate, propylene oxide modified trimethylolpropane triacrylate, epichlorohydrin modified trimethylolpropane triacrylate, pentaerythritol tetraacrylate, pentaerythritol tetramethacrylate, tetramethylolmethane tetraacrylate, ethylene oxide modified phosphate triacrylate, epichlorohydrin modified glycerol Polyfunctional acrylates typified by reacrylate, dipentaerythritol hexaacrylate, dipentaerythritol monohydroxypentaacrylate, or their modified silsesquioxanes, or the corresponding methacrylate monomers, trifunctional methacrylate esters, ε -Caprolactone-modified tris (acryloxyethyl) isocyanurate and the like. The blending amount of the tri- or higher functional acrylate monomer is 40 to 400 mass when the monomer having (meth) acryloyl group and glycidyl group in the molecule and having a viscosity at 25 ° C. of 10 mPa · s or less is 100 mass parts. Parts, preferably 50 to 300 parts by mass.

  Examples of the photopolymerization initiator include a photoradical polymerization initiator and a photocationic polymerization initiator.

  Any radical photopolymerization initiator can be used as long as it is a compound that generates radicals by light, laser, electron beam or the like and initiates radical polymerization reaction. Examples of the photo radical polymerization initiator include benzoin and benzoin alkyl ethers such as benzoin, benzoin methyl ether, benzoin ethyl ether, and benzoin isopropyl ether; acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2- Acetophenones such as diethoxy-2-phenylacetophenone and 1,1-dichloroacetophenone; 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino Aminoacetophenones such as -1- (4-morpholinophenyl) -butan-1-one, N, N-dimethylaminoacetophenone; 2-methylanthraquinone, 2-ethylanthraquinone, 2-t-butylanthraquinone, 1-chloro Anthraquinones such as anthraquinone; thioxanthones such as 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone and 2,4-diisopropylthioxanthone; ketals such as acetophenone dimethyl ketal and benzyldimethyl ketal; 4,5-triarylimidazole dimer; riboflavin tetrabutyrate; thiol compounds such as 2-mercaptobenzimidazole, 2-mercaptobenzoxazole, 2-mercaptobenzothiazole; 2,4,6-tris-s-triazine, Organic halogen compounds such as 2,2,2-tribromoethanol and tribromomethylphenyl sulfone; benzophenones such as benzophenone, 4,4′-bisdiethylaminobenzophenone, or xanthone And 2,4,6-trimethylbenzoyldiphenylphosphine oxide and the like.

  The above radical photopolymerization initiators can be used alone or in combination of two or more. Furthermore, in addition to these, tertiary amines such as N, N-dimethylaminobenzoic acid ethyl ester, N, N-dimethylaminobenzoic acid isoamyl ester, pentyl-4-dimethylaminobenzoate, triethylamine, triethanolamine, etc. Photoinitiator aids can be used. In addition, a titanocene compound such as CGI-784 having an absorption in the visible light region (manufactured by BASF Japan) or the like can also be added to the photoradical polymerization initiator in order to accelerate the photoreaction. The components added to the radical photopolymerization initiator are not limited to these, as long as they absorb light in the ultraviolet or visible light region and radically polymerize unsaturated groups such as (meth) acryloyl groups. These are not limited to photopolymerization initiators and photoinitiator aids, and can be used alone or in combination.

  As the photocationic polymerization initiator, any compound that initiates a cationic polymerization reaction by light, laser, electron beam or the like can be used. Photocationic polymerization initiators that generate cationic species by light include, for example, diazonium salts, iodonium salts, bromonium salts, chloronium salts, sulfonium salts, selenonium salts, pyrium salts, thiapyrylium salts, pyridinium salts and other onium salts; tris (trihalo Halogenated compounds such as methyl) -s-triazine and derivatives thereof; 2-nitrobenzyl ester of sulfonic acid; iminosulfonate; 1-oxo-2-diazonaphthoquinone-4-sulfonate derivative; N-hydroxyimide = sulfonate; (Methanesulfonyloxy) benzene derivatives; bissulfonyldiazomethanes; sulfonylcarbonylalkanes; sulfonylcarbonyldiazomethanes; disulfone compounds and the like. Commercially available photocationic polymerization initiators include Cyracure UVI-6970, UVI-6974, UVI-6990, UVI-6950 (trade names manufactured by UCC) and Irgacure 261 (trade names manufactured by BASF Japan). , SP-150, SP-152, SP-170 (above, trade names manufactured by Asahi Denka Kogyo Co., Ltd.), DAICAT II (trade names manufactured by Daicel Chemical Industries, Ltd.), UVAC1591 (Daicel Cytec Co., Ltd.) Product name), CI-2734, CI-2855, CI-2823, CI-2758 (above, product name manufactured by Nippon Soda Co., Ltd.), PI-2074 (product name manufactured by Rhône-Poulein Co., Ltd.), FFC509 (trade name manufactured by 3M Co., Ltd.), Rhodesill Photoinitiator 2074 (trade name manufactured by Rhodia Co., Ltd.), BBI-1 02, BBI-101 (trade name manufactured by Midori Chemical Co., Ltd.), CD-1012 (trade name manufactured by Sartomer Co., Ltd.) and the like.

  Examples of the thermosetting catalyst include imidazole, 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 4-phenylimidazole, 1-cyanoethyl-2-phenylimidazole, 1- ( Imidazole derivatives such as 2-cyanoethyl) -2-ethyl-4-methylimidazole; dicyandiamide, benzyldimethylamine, 4- (dimethylamino) -N, N-dimethylbenzylamine, 4-methoxy-N, N-dimethylbenzylamine Amine compounds such as 4-methyl-N, N-dimethylbenzylamine, hydrazine compounds such as adipic acid dihydrazide and sebacic acid dihydrazide; phosphorus compounds such as triphenylphosphine, and the like. Examples of commercially available thermosetting catalysts include 2MZ-A, 2MZ-OK, 2PHZ, 2P4BHZ, 2P4MHZ (both trade names of imidazole compounds) manufactured by Shikoku Kasei Kogyo Co., Ltd., U-CAT3503N manufactured by San Apro, U -CAT3502T (all are trade names of blocked isocyanate compounds of dimethylamine), DBU, DBN, U-CATSA102, U-CAT5002 (all are bicyclic amidine compounds and salts thereof), and the like. These may be used alone or in admixture of two or more. The blending amount of the thermosetting catalyst is 0.1 to 5 parts by mass when the monomer having a (meth) acryloyl group and a glycidyl group in the molecule and having a viscosity at 25 ° C. of 10 mPa · s or less is 100 parts by mass, Preferably it is 0.5-4 mass parts.

  The photocurable thermosetting composition for inkjet according to the present invention may contain a diluent solvent for the purpose of adjusting the viscosity. Examples of the diluting solvent include ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene, xylene and tetramethylbenzene; cellosolve, methyl cellosolve, butyl cellosolve, carbitol, methyl carbitol, butyl carbitol, propylene glycol Glycol ethers such as monomethyl ether, propylene glycol monoethyl ether, dipropylene glycol diethyl ether, triethylene glycol monoethyl ether; ethyl acetate, butyl acetate, cellosolve acetate, butyl cellosolve acetate, carbitol acetate, butyl carbitol acetate, propylene glycol Acetic acid ester such as monomethyl ether acetate and dipropylene glycol monomethyl ether acetate Alcohols such as ethanol, propanol, ethylene glycol and propylene glycol; aliphatic hydrocarbons such as octane and decane; petroleum solvents such as petroleum ether, petroleum naphtha, hydrogenated petroleum naphtha and solvent naphtha It is done.

  Further, the photo-curable thermosetting composition of the present invention may be prepared by adding colorants such as phthalocyanine blue, phthalocyanine green, iodin green, disazo yellow, crystal violet, carbon black, naphthalene black, hydroquinone, hydroquinone as necessary. Known and commonly used polymerization inhibitors such as monomethyl ether, tert-butylcatechol, pyrogallol, phenothiazine, etc., antifoaming agents and / or leveling agents such as silicone, fluorine and polymer, imidazole, thiazole, triazole, silane Additives such as adhesion-imparting agents such as coupling agents can be blended.

  EXAMPLES Hereinafter, although an Example is shown and this invention is demonstrated concretely, this invention is not limited only to these Examples. In the following, “part” means part by mass unless otherwise specified.

  About Examples 1-5 and Comparative Examples 1-6, each component was mix | blended in the ratio shown in Table 1, this was stirred with the dissolver, and also it filtered with a 1 micrometer disk filter, and obtained each composition.

<Monomer having a (meth) acryloyl group and a glycidyl group in the molecule and a viscosity at 25 ° C. of 10 mPa · s or less>
GMA: Glycidyl methacrylate (viscosity 2 mPa · s (25 ° C.))
4HBAGE: 4-hydroxybutyl acrylate glycidyl ether (viscosity 7 mPa · s (25 ° C.))
<Monomers other than “monomer having a (meth) acryloyl group and a glycidyl group in the molecule and a viscosity at 25 ° C. of 10 mPa · s or less”>
EA-1010N: Compound in which acrylic acid is added to one epoxy group of bisphenol A type epoxy resin, manufactured by Shin-Nakamura Chemical Co., Ltd. (viscosity 22,000 mPa · s (25 ° C.))
AGE: Allyl glycidyl ether with allyl group and glycidyl group (viscosity 1 mPa · s (25 ° C))
4HBA: 4-hydroxybutyl acrylate (viscosity 10 mPa · s (25 ° C.))
DPGDA: Dipropylene glycol diacrylate (viscosity 12 mPa · s (25 ° C.))
M-100: 3,4-epoxycyclohexylmethyl methacrylate Compound having methacryloyl and alicyclic epoxy group, manufactured by Daicel Chemical Industries (viscosity: 10 mPa · s (25 ° C.))
<Trifunctional or higher acrylate monomer>
PETA: Pentaerythritol triacrylate TMPTA: Trimethylolpropane triacrylate SR9011: Trifunctional methacrylate ester M327: ε-caprolactone-modified tris (acryloxyethyl) isocyanurate (manufactured by Toagosei Co., Ltd.)
<Thermosetting catalyst>
2E4MZ: 2-ethyl-4-methylimidazole <photopolymerization initiator>
IRG819: Irgacure 819 manufactured by BASF

The following characteristic tests were performed on each of the above compositions. The results are shown in Table 2.

<Applicability>
An L-shaped line having a width of 100 μm and a side length of 20 mm was printed on an inkjet print paper (Epson Photomat Paper A4) using an Fujifilm inkjet printer, Dimatix Materials Printer DMP-2831. The L-shaped line was observed with a loupe, and the shape of the line was evaluated as follows.
○: The line is not blurred or twisted and drawn correctly.
X: The line cannot be confirmed, or the line is blurred or twisted.

<Photocurability>
Using a Fujifilm inkjet printer Dimatix Materials Printer DMP-2831, a copper-clad laminate for printed wiring boards (FR-4 thickness 1.6 mm, size 150 × 95 mm) with the above composition having a size of 10 × 20 mm. A rectangular pattern was printed. Immediately thereafter, the printed laminate was irradiated with UV at an integrated light amount of 300 mJ / cm ² using a high-pressure mercury lamp. About the said rectangular pattern, it evaluated as follows about the hardening state after UV irradiation.
○: Cured and shape retained.
X: Not cured.

<Adhesion>
Using a Fujifilm inkjet printer Dimatix Materials Printer DMP-2831, a copper-clad laminate for printed wiring boards (FR-4 thickness 1.6 mm, size 150 × 95 mm) with the above composition having a size of 10 × 20 mm. A rectangular pattern was printed so that the film thickness was 15 μm. Immediately thereafter, the printed laminate was irradiated with UV light at a cumulative light quantity of 300 mJ / cm ² using a high-pressure mercury lamp. Then, the UV-irradiated laminate was heated at 150 ° C. for 30 minutes in a hot air circulation drying furnace, and the pattern was thermally cured to obtain each test piece. The rectangular pattern of each test piece was cut one by one vertically and horizontally with a cutter knife, peeled with cellophane tape, and the peeling was evaluated as follows.
○: Mostly no peeling is observed.
X: There is peeling that is largely transferred to Serotep (registered trademark).

<Chemical resistance>
About each said composition, each test piece was produced by the method similar to the method described in the said adhesive test. Each test piece was immersed in propylene glycol monomethyl ether acetate for 30 minutes at room temperature, taken out, and then dried. About each test piece after drying, the state of the coating film was visually evaluated as follows.
○: No change in the state of the coating film ×: Floating on the coating film, peeling

<Heat resistance>
About each said composition, each test piece was produced by the method similar to the method described in the said adhesive test. About each said test piece, the rosin system flux was apply | coated, and it was immersed in the soldering bath of 260 degreeC for 10 second, this was taken out and naturally cooled. After repeating this test three times, the state of the coating film of each test piece was visually evaluated as follows.
○: No change in the state of the coating film ×: Floating on the coating film, peeling

<Insulation>
About the composition of the said Examples 1-5, the method as described in an adhesive test except having used the comb-type electrode B coupon of the IPC B-25 test pattern instead of the copper clad laminated board, and having made film thickness into 40 micrometers. Each test piece was prepared in the same manner as described above. A DC 500 V bias was applied to the test piece, and the insulation resistance value was measured. When the value was 100 GΩ or more, it was rated as “◯”, and when it was less than 100 GΩ, it was marked as “X”.

以上から、本発明のインクジェット用光硬化性熱硬化性組成物は、インクジェットプリンターを用いて、プリント配線板用の基板上に直接パターンを描画することができ、また塗布性に問題なく、密着性、耐薬品性、耐熱性に優れた樹脂絶縁層を形成することができる。

From the above, the photocurable thermosetting composition for inkjet of the present invention can draw a pattern directly on a substrate for a printed wiring board using an inkjet printer, has no problem in applicability, and has good adhesion. A resin insulating layer having excellent chemical resistance and heat resistance can be formed.

Claims (4)

A monomer having a (meth) acryloyl group and a glycidyl group in the molecule and having a viscosity at 25 ° C. of 10 mPa · s or less,
Trifunctional or higher acrylate monomers;
A thermosetting catalyst;
Including a photopolymerization initiator,
The blending amount of the thermosetting catalyst is 0.1 to 5 parts by mass with respect to 100 parts by mass of the monomer having a (meth) acryloyl group and a glycidyl group in the molecule and a viscosity at 25 ° C. of 10 mPa · s or less. A photocurable thermosetting composition for inkjets for low-temperature curing at 150 ° C. or lower.   The monomer having a (meth) acryloyl group and a glycidyl group in the molecule and having a viscosity at 25 ° C. of 10 mPa · s or less is glycidyl methacrylate or 4-hydroxybutyl acrylate glycidyl ether. A photocurable thermosetting composition for inkjet.   The blending amount of the trifunctional or higher acrylate monomer is 15 to 400 parts by mass with respect to 100 parts by mass of the monomer having a (meth) acryloyl group and a glycidyl group in the molecule and having a viscosity at 25 ° C. of 10 mPa · s or less. The photocurable thermosetting composition for inkjet according to claim 1, wherein the photocurable thermosetting composition is for inkjet. A printed wiring board comprising a resin insulating layer made of a cured product of the photocurable thermosetting composition for inkjet according to any one of claims 1 to 3.