JPH038894A - Surface sizing agent and surface sizing method using same - Google Patents

Abstract

PURPOSE:To provide the title sizing agent capable of giving excellent sizing performance with little foaming during coating process, containing as effective component, a water-soluble polymer produced from a specific alpha-olefin and a (meth)acrylic ester, etc. CONSTITUTION:The objective sizing agent containing, as effective component, a water-soluble polymer produced from (A) 1-70mol% of an alpha,beta-unsaturated dicarboxylic half ester or its salt (said ester being 4-24C monohydric alcohol ester), (B) 0-70mol% of an alpha,beta-unsatured dicarboxylic acid or its salt, (C) 5-65mol% of a 8-30C straight chain alpha-olefin, (D) 5-65mol% of a (meth)acrylic ester with its constituent alcohol being of >=6C, and (E) <30mol% of a unsaturated monomer copolymerizable with the components A, B, C. It is preferable that 10-90mol% of the component B is a half amide (e.g. of maleic acid).

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a surface sizing agent and a surface sizing method using the surface sizing agent. For more details,
The present invention relates to a surface sizing agent that has good sizing effects and particularly low foaming properties, and a surface sizing method using the surface sizing agent.

[Prior art] Aqueous solutions of styrene-maleic acid or α-olefin-maleic acid co-11 have been known as surface sizing agents, but both are insufficient in terms of size effects and low foaming properties. It is. Therefore, when these surface sizing agents are applied to base paper, there is a disadvantage that operability is lowered due to foaming.

[Five Problems to be Solved by the Invention] In order to solve the above-mentioned problems, the present inventors have conducted extensive studies focusing on α-olefin-maleic acid polymers, and have found that a specific α-olefin and a specific (meth) ) A surface size fi11 obtained by using an aqueous polymer obtained by copolymerizing acrylic ester with maleic anhydride and maleic anhydride nide ester in a specific ratio, respectively, is used as a surface tin/rs agent known in Juto. Compared to other products, it has much lower foaming properties and is excellent.
We have found that this can produce a positive effect. Furthermore, we have discovered the remarkable fact that when a partially amidated product of the above aqueous compound is used, it has excellent solubility in water in addition to the characteristics mentioned above. In addition, by using a surface sizing agent made of an aqueous polymer obtained by changing the charging time of the (meth)acrylic acid ester described in 1- above during the production of the aqueous polymer and its partially amidated product, It has also been found that foamability can be significantly improved.

The present invention was first completed based on these facts.

(Step 3 for Solving the Problems) That is, the present invention provides (n) α,β-unsaturated cyclocarboxylic acid half ester or its privately produced ester (I7 (however, ester is a carbon atom having 4 to 24 carbon atoms).
(Ester of Ill alcohol) Ha) component) 1-70
Molar volume (b) α,β-unsaturated dicarboxylic acid or its salt 11
1st position (component (b)) 0 to 70 moles (c) carbon number 8 to
30 linear α-olefins (component (c)) 5 to 65 moles and (d) acrylic ester and/or methacrylic ester in which the constituent alcohol has 6 or more carbon atoms (component (d)) 5 to 65 (e) An aqueous electropolymer consisting of less than 30 moles of an unsaturated monomer (component (e)) copolymerizable with the above-mentioned (a), (b) and (c) components as an active ingredient. and (a) an α,β-unsaturated dicarboxylic acid ester or salt thereof at the 1 p-position <
4 monohydric alcohol ester) (component (a)) 1-
70 moles (b) α,β゛-unsaturated dicarboxylic acid or its salt fn
li fu ((b) component) 0 to 70 mo) L% (c) carbon number 8
~30 linear α-olefins ((L:) component) 5-6
5 mol% and (d) acrylic ester and/or methacrylic ester having 6 or more carbon atoms in the constituent alcohol (component (d)) 5 to 65 mol (c) 1iii (a), (b) and (c
) component ((e) component) 30
The present invention relates to a surface sizing method characterized by using a surface sizing agent characterized in that the active ingredient is an aqueous polymer composed of less than mol %.

Component (a) which is a constituent component of the surface sizing agent of the present invention (α
, β-unsaturated dicarboxylic acid half ester or its derivatives), l having 4 to 24 carbon atoms forming a half ester
[b] As the tl alcohol, the following various types can be mentioned. For example, butyl alcohol, pentyl alcohol, hexyl alcohol, cyclohexyl alcohol, octyl alcohol, 2-ethylhexyl alcohol, decyl alcohol, hexadecyl alcohol,
Aliphatic 1 (such as 1Ii alcohol and Hensyl alcohol) monohydric alcohols of group 76 such as octadecyl alcohol and eicosyl alcohol, and two or more thereof]-
It can be said that it is a mixed item. 5 Among these, aliphatic alcohols having 6 to 6 carbon atoms are preferred from the viewpoint of size effect and foam quality. Here, the number of carbon atoms in the monohydric alcohol is 4
If it is less than 24, a satisfactory size effect and foam suppressing effect cannot be obtained, and if it exceeds 24, the water solubility of the polymer is poor and a stable aqueous solution cannot be obtained, which is not preferred.

(b) is an optional component of the surface sizing agent of the present invention;
Component (α, β-unsaturated dicarboxylic acid or its salt m-position)
Examples include dicarboxylic acids such as maleic acid, fumaric acid, itaconic acid, and citraconic acid, anhydrides, and salts of the dicarboxylic acids. Among the dicarboxylic acids, maleic acid, maleic anhydride and itaconic acid are preferred. In addition, for components (a) and (b), examples of the salts include alkali metal salts such as sodium salts or potassium salts, ammonium salts, aliphatic amine salts having 1 to 12 carbon atoms, alkanolamine salts, etc. be able to. Among these salts, sodium salts, potassium salts, and ammonium salts are preferred. These salts may be either completely neutralized salts or partially neutralized salts.

8 to 30 carbon atoms as a component of the surface sizing agent of the present invention
The linear α-olefins (hereinafter referred to as component (c)) include l-octene, 1-nonene, 1-decene, 1-
Dodecene, l-tetradecene, 1-pentadecene, l-
hexadecene, nee-octadecene, 1-eicosene, 1
Examples include -tetradecene, 1-oftacocene, 1-triacontin, and the like. Considering the performance of the resulting surface sizing agent, particularly the size effect and foam suppressing effect, linear α-olefins having 8 to 20 carbon atoms are more preferred. Linear α-olefins with less than 8 carbon atoms tend to have lower sizing effects and foam-inhibiting effects, and when linear α-olefins with more than 30 carbon atoms are used, the resultant surface sizing agent Both are unfavorable because the solubility in water decreases. The reason why branched-chain ones were excluded is that they have a higher foaming property than linear α-olefins.

Component (d), which is a component between the surface sizes of the present invention, is
It is a (meth)acrylic acid ester whose constituent alcohol component has 6 or more carbon atoms. Specifically, the alcohol components of Kowara are hexyl alcohol, octyl alcohol, 2
- Ethylhexyl alcohol, nonyl alcohol, decyl alcohol, F-decyl alcohol, tetradecyl alcohol, pentadecyl alcohol, hexadecyl alcohol, octadecyl alcohol, eicosyl alcohol, tridecyl alcohol, tetradecyl alcohol,
Examples include hexadecyl alcohol, octadecyl alcohol, cyclohexyl alcohol, benzyl alcohol, etc., and these may be used alone or in combination. The performance of the resulting surface sizing agent, especially the low total foaming property of the sizing agent, was evaluated as 4 b! Accordingly, among these, preferably the constituent alcohol has 8 to 30 carbon atoms. When the number of carbon atoms in the constituent alcohol is less than 6, the foaming property becomes high. The 4-carbon number limit is not particularly limited, but if it exceeds 30, there is a disadvantage in terms of raw human hair.

Other unsaturated monomers (hereinafter referred to as component (e)) that are optional constituents of the surface sizing agent of the present invention include acrylic acid, methacrylic acid, acrylamide, methacrylamide, acrylonitrile, 2-hydroxy Water-soluble monomers such as edyl methacrylate 11 ii 1, oil-soluble monomers such as acrylate, methacrylate, styrene, α-methylstyrene, vinyl acetate, glycidyl methacrylate, etc. 5
), and these can be used within the scope of the present invention, and in general, it is preferable that the amount of (17) be less than 30 moles based on the total amount of the carrier used.

-1- (a), (b), (c), (d)
The various components (e) and (e) are used in the following composition ratios.

The amount of component (J) in the polymer is usually 1 to 70% by mole, preferably 5 to 50% by mole. If the composition ratio of component (a) is less than 1 mole, a satisfactory size effect cannot be obtained, and if it exceeds 70 moles, the foaming property increases, which is not preferable. (b) The composition ratio of the components is usually 0.
70 molt, preferably 5 to 50 molt.

In addition, it is preferable that 10 to 900 to 90 mol% of the component (b) is midized from the viewpoint of the solubility of the resulting surface sizing agent in water. (c) The composition ratio of the component is usually 5~
65 mol t, preferably 10 to 61) mol t.

When the amount of component (c) is less than 5 moles and when it exceeds 65 moles, the size effect tends to be reduced, and both are unfavorable.

The composition ratio of the (tJ) component is usually 5 to Ii5 mol%, preferably 10 to 600 to 60 mol%. (If component (j) is less than 5 moles, the foaming property tends to increase, and if it exceeds 65 moles, the size effect tends to decrease, which is not preferable.) Component (e) The composition ratio of is usually less than 30 moles.

The degree of neutralization of all carboxyl J,t in the polymer is usually 50
It is preferable that the molar value is greater than or equal to tiO;[-r]. Adjustment of the degree of neutralization can be carried out in advance at the stage of preparing the td compound, or it can also be carried out after the production of the polymer. There are no particular restrictions on the amount of half-amide groups in the polymer, or 10 to 900 to 90 mol% or 20 to 800 to 80% of the component (b) is selected from the viewpoint of solubility of the aqueous polymer in water. Mol% is good. (i) Amidation can be carried out in advance at the fl'-N1 stage and can be carried out after the production of the polymer.

The surface sizing agent of the present invention contains various ingredients ((a) to (e)
5. component) in the presence of a suitable +1 initiator; t(, Il
'l[Can be easily manufactured by combining. There are no particular restrictions on the combination method; bulk polymerization,
Various methods such as solution ν [coupling] can be employed as appropriate.

In the case of solution polymerization, aromatic hydrocarbons such as henzhen and toluene, lower ketones such as acetone and methyl ethyl ketone, ethyl acetate, chloroform, dimedylformamide, etc. can be used alone or in suitable combinations of 1T as solvents. There are no particular restrictions regarding the types of penalties for starting use, including organic peroxides such as benzoyl peroxide, dicumyl peroxide, and lauryl peroxide, azobisisobunalonitrile, and azobisdimethylhydronitrile. Other redox catalyst type Izuwa can also be used. Further, during polymerization, a 3n transfer agent such as mercaptans and secondary alcohols can also be used. The polymerization temperature is usually about 80 to 140°C, and the reaction time is about 1 to I Off, ν.

In the present invention, the following improvements have been made! ! It is better to use the I construction method.

In other words, in order to copolymerize component (a), component (b), component (c), component (d), and component (c), Clear skies, (c
) Preparation of ingredients, (e) Preparation of ingredients, and (d)
Preparation of the components The first 5 to 9 seconds of F71L are added at the same time or preferably dropwise, and after copolymerization reaches a polymerization rate of about 80 to OOt (hereinafter this step is referred to as the first stage 1).
It is preferable to charge the remaining component (d) and complete the copolymerization (hereinafter, this step will be referred to as the second step).

By dividing component (d) into the mixture, the foamability is greatly improved. If the charge of component (d) in the first step exceeds 95 L, it is unlikely that the foamability of the resulting aqueous m-coalescence can be significantly improved. However, the amount of preparation is 5~j (5 cities, 9 [t, preferably 20~
80 cities (according to Kei Tsuji. The reaction temperature in the first stage is 1
The reaction time was 1 to 10 hours, and the reaction was carried out until the 1n ratio was about 80 (XRt' or more), and then the reaction was carried out to the second stage. The amount of component (d) to be charged is 95 to 5 tons, preferably 80 to 20 tons.The reaction temperature in the second stage is about 80 to 140°C, and the reaction time is 1-8. It is a time linearity.

In addition, half-amide 1 is prepared by adding a predetermined amount of ammonia, aliphatic amine having 1 to 12 carbon atoms, alkanolamine, etc. to the copolymer obtained above, and then reacting. Temperature 20℃
Hereinafter, the culm degree is preferably 30 to 100°C, and the reaction time is 0.
．． The reaction may be carried out for about 5 to 8 hours, preferably for 0.5 to 3 hours. The various copolymers obtained are adjusted to the desired pH using a neutralizing agent such as an alkali metal hydroxide such as potassium hydroxide or sodium hydroxide, ammonium hydroxide, an aliphatic amine having carbons a1 to 12, or an alkanolamine. A neutralization operation may be performed as appropriate.

By any of the production methods described above, it is usually possible to easily obtain a water-soluble polymer, and in some cases a water-dispersible polymer. The molecule j1 of 1 aqueous 1 ■ coalescence is usually 1.000 ~
l, [about 100,000, preferably 2,000 to
The range is 00.000. (If the amount is less than 1.000, the seven-fold size effect is not fF7, and oo
If it exceeds o or ooo, the viscosity of the +I combined aqueous solution or dispersion tends to increase, resulting in poor workability.

The surface sizing agent of the present invention has the above aqueous 11-coalescence.
It is an active ingredient.

There are no particular restrictions on the base paper to which the surface sizing agent of the present invention is applied, and it is hardly affected by valves, fillers, internal sizing agents, PL+ during papermaking, paper strength agents, retention aids, etc. For example, base paper for Tττ paper and coated paper base paper made under acidic conditions, base paper for L-weight paper and coated paper base paper made for neutral paper with internal addition of alkyl ketene dimer or alkenyl succinic anhydride, base paper for liners, etc. I can give it to you. It can also be suitably used for base paper containing WiI-containing paper.

The surface sizing agent of the present invention can not only be used alone, but also in combination with oxidized starch, sodium alginate, carboxymethyl cellulose, acrylamide polymer, polyvinyl alcohol, and the like.

Furthermore, the surface sizing agent of the present invention can be coated on the various types of base papers listed above by conventionally known coating methods, such as impregnation, size pressing, calendering, and spraying. The amount of cloth is usually 0.001 to 5z/r+f (hard 1f fraction), preferably 0.005 to 1g/ba.

Compared to conventional surface sizing agents, sizing agents have better solubility in water and less foaming, making them suitable for use in actual equipment. It exhibits the advantage of being able to obtain paper.

〔Example〕

Hereinafter, the present invention will be specifically explained with reference to Examples and Comparative Examples, but the present invention is not limited to these exceptions. In addition, in each example, all parts and percentages are based on t9it) unless otherwise specified.

No≦hi! Example l Maleic anhydride 711.4 was added to a flask equipped with a stirrer, a cooling tube, a dropping funnel, nitrogen, a kernel inlet tube and a thermometer.
(mainly 40 mol), 4 parts (10 mol t) of isobutyl alcohol half ester of maleic anhydride, and 47.3 parts of toluene were added, and the mixture was stirred under a nitrogen stream with stirring for 11 hours.
The temperature was raised to 0°C.

89.6 parts (40 mol t) of 1-decene and 36.9 parts (10 mol t) of 2-ethylhexyl acrylate were added to the droplet funnel.
In another dropping funnel, add 11.4 parts of monobutyl peroxybenzoate and 40 parts of toluene.
I prepared a section. These were added dropwise into the flask from the dropping funnel over a period of about 1.5 hours, and kept under reflux for about 1 hour.

Thereafter, 4.6 parts of thi-butyl peroxy-2-ethyl hexaate and 20 parts of toluene were added dropwise over about 30 minutes, and the mixture was kept warm for 1 hour.

The toluene was distilled off under reduced pressure, and the 1" compound was mixed with 7.2 parts of sodium hydroxide, a predetermined amount of water, and 98 parts of 2H ammonia water.
．． By neutralizing with 4 parts, an aqueous solution of water-soluble + J + E
5.54k, pl+ is 9.0. The viscosity at 25℃ is 4!
IO(:ps).

Examples 2 to 10 Various surface sizing agents were obtained by carrying out reactions in the same manner as in Example 1, except that at least one of the type of I'Ilt substance used and its composition was changed.

Each of these constants is shown in Table 1.

Example 11 In a flask similar to Example 1, 98 parts of maleic anhydride (
50 mol t) and 53.9 parts of toluene were charged, and the temperature was raised to 110°C under a stirring nitrogen stream.

89.6 parts (40 moles) of 1-decene and 1 part (1 mole) of lauryl acrylate were placed in a dropping funnel, and 11.4 parts of L-butyl peroxybenzoate and 40 parts of toluene were placed in another dropping funnel. The mixture was poured into a flask through a dropping funnel for about 1.F1 hour, and kept warm under flowing water for about 1 hour.

Thereafter, 4.6 parts of butyl peroxy-2-ethyl hexaate and 20 parts of toluene were added dropwise to remove about 100 ml of toluene, and the mixture was kept warm for 11 hours.

Then, after the system internal temperature was set to 110 to 90°C, 18.4 parts of isobutyl alcohol was charged from the dropping funnel, and the temperature was kept at the same grade of 7 for 1 hour to perform a post-esterification reaction. Historically, a water-soluble IK combined aqueous solution was prepared by distilling off toluene under reduced pressure and neutralizing the polymer with 7.2 parts of sodium hydroxide, a predetermined amount of water, and 98.4 parts of aqueous ammonia to 2 tl'. °f, the water-soluble mixture was used as the surface sizing agent of the present invention. The appearance of this product was pale yellow and transparent, the nonvolatile content was 25.54%, the pl+ was 9.1, and the viscosity at 25°C was 11,100 cps.

Example 12 The total amount of the toluene distilled moe obtained in Example 2 was added to 70 to 80° C., and then 34.0 parts of anthonium carbonate (NI+3 content 60 mole 9
6) was added. The amidation reaction was carried out by keeping the mixture at the same temperature for 11 and ν.

Toluene was distilled off under reduced pressure, and the n compound was mixed with 4.8 parts of sodium hydroxide, a predetermined amount of water, and 4 parts of 28% aqueous ammonia.
By neutralizing with 5.4 parts, the water-soluble f ■ combined aqueous solution is 1:! , the size of the table Wtj of the water-soluble IF combined invention was reduced. The appearance of this product is +'Q color transparent aqueous solution, non-volatile content is 25.5 wood, pu is! 1.1.The viscosity at 25℃ is 6! It was +0 eps.

Example 13 In a flask similar to Example 1, 78% of maleic anhydride was added.
4 parts (・100 mol), 34.4 parts (10 mol*) of isobutyl alcohol half ester of maleic anhydride, and 539 parts of toluene were charged, and the mixture was stirred in a nitrogen stream F.
The temperature was raised to n°C.

A dropping funnel was charged with 89.6 parts (100 moles) of 1-ndecene and 6 parts (7 moles) of lauryl acrylate, and 114 parts of 1-butyl peroxyhenzoate and 40 parts toluene were placed in another f4 funnel. (Prepare) V. These were added dropwise into the flask from the dropping funnel for about 1.5 hours, and kept warm under flowing water for about 1 hour. The number of polymerizable groups at the u and ll points was 85t. Its base, butyl peroxy-2-ethyl hexaate 4 (;
and 20 parts of toluene were charged into a dropping funnel, and 1.14 parts (3 moles) of lauryl methacrylate was charged into another dropping funnel, and these were poured down over a period of about 30 minutes and kept warm for 1 hour. Toluene is removed under reduced pressure F,
By neutralizing the In compound with 7.2 parts of sodium hydroxide, a predetermined 11[mu] of water and 98.4 parts of 2; It was used as a drug. The appearance of this product is a dark colored emulsion, the non-volatile content is 25.5%, and the pH is! 1.0.2
The viscosity at 5°C was 3101s.

Example 14 A surface sizing agent was obtained by carrying out the reaction in the same manner as in Example 13, except that the amount of lauryl acrylate added in portions was changed as shown in Table 1. The appearance of this b is a colored emulsion, the non-volatile content is 254+>, and the p++ is! 1.1, the viscosity at 25°C was 530 cps.

Examples 15 to 17 In Example 2, the type of linear α-olefin was
A surface sizing agent was obtained by carrying out the reaction in the same manner except for the changes shown in the table. These nominal constants are shown in Table 1.

Comparative Examples 1 to 6 Various surface sizing agents were obtained by carrying out the reaction in the same manner as in Example 1, except that at least one type of the single fine substance used and its composition were changed.

Each of these constants is shown in Table 1.

The performance evaluation of the various fire sizing agents obtained in the following was conducted by the following method.The results are shown in Table 2.

(Size effect (^) Base paper Acid paper weight 71g/m', Stekicht 0 seconds, Internal additive chemical (addition rate to valve) Nitalc 20'l (Reinforced rosin sizing agent (made by Ayu Kagaku Shigyo), Product name "Sizevine E") 0.05!k, Sulfuric acid band 2.5t ■ Neutral paper basis weight 1i56/rn', Stekicht 0 seconds, Internally added chemicals (
Calcium carbonate 2t1%, alkenyl succinic anhydride sizing agent (manufactured by Arayo Kagaku Kogyo ■, trade name "Sizevine S^850J") fl, 05*, sulfuric acid band 0.5%, cationized starch 0 .4t, anionic retention agent (product name: ``Ni5flJ'' manufactured by Arayo Kagaku fRen@)
') Ll, 01% (1)) Surface sizing device: Lahosai press table 1fii size cutting: Oxidized starch (solid content application 1m118
g, /rn'') and the surface sizing agent of the present invention (Hard J [partial application fit is described in Dai 2]) were mixed and used.

Drying conditions: Two-rotation auto dryer 1, 30℃×
1 min Steckicht size Ji, +1 according to SP-8122.

Cob size degree: According to JI511-8140.

(2) 1000 parts of a sizing solution to which 5 tons of foamable oxidized starch and surface size, 'il+ 0.05* were added, was placed in a 2e circle ↑ 1 type flask and kept at 145°C. Stir for 10 minutes at 4000 rpm using a stirrer with a 3-blade propeller. Foaming:
was measured.

(1:) Paper linear 3F value (effects of the invention) By the production method of the present invention, it is possible to easily obtain a specific aqueous polymer which is an effective ingredient in surface size reduction.

The surface size coating containing this water-based polymer as an active ingredient not only exhibits excellent size performance, but also has almost no foaming during coating, making it extremely easy to apply to actual equipment.
It also has the effect of easily providing paper of a good size.

Arakawa Chemical Industry Co., Ltd.

Claims (1)

[Scope of Claims] [1] (a) α,β-unsaturated dicarboxylic acid half ester or its salt unit (however, ester is one having 4 to 24 carbon atoms)
ester of alcohol) (component (a)) 1 to 70 mol% (b) α, β-unsaturated dicarboxylic acid or its salt unit (
(h) Component) 0 to 70 mol% (c) Linear α-olefin having 8 to 30 carbon atoms ((c)
component) 5 to 65 mol% and (d) acrylic ester and/or methacrylic ester whose constituent alcohol has 6 or more carbon atoms (component (d)) 5 to 65 mol% (e) the above (a), (b) ) and an aqueous polymer comprising less than 30 mol % of an unsaturated monomer (component (e)) copolymerizable with component (c) as an active ingredient. [2] The surface sizing agent according to claim 1, wherein 10 to 90 mol% of the component (b) is a half-amide. [3] The above (a) component, (b) component, (c) component, (d
In copolymerizing component ) and component (e), (a
5 to 95% by weight of the total amount of component (b), the total amount of component (c), the total amount of component (e), and the total amount of component (d), approximately 80% by weight. ~10
After copolymerizing until the polymerization rate reached 0%, the remaining (d
3. The surface sizing agent according to claim 1 or 2, wherein the active ingredient is an aqueous polymer obtained by charging the component () and completing the copolymerization. [4] (a) α, β-unsaturated dicarboxylic acid half ester or its salt unit (however, ester is 1 with 4 to 24 carbon atoms)
ester of alcohol) (component (a)) 1 to 70 mol% (b) α, β-unsaturated dicarboxylic acid or its salt unit (
(b) Component) 0 to 70 mol% (c) Linear α-olefin having 8 to 30 carbon atoms ((c)
component) 5 to 65 mol% and (d) acrylic ester and/or methacrylic ester whose constituent alcohol has 6 or more carbon atoms (component (d)) 5 to 65 mol% (e) the above (a), (b) ) and an aqueous polymer comprising less than 30 mol% of an unsaturated monomer (component (c)) copolymerizable with component (c) as an active ingredient. A surface sizing method characterized by: [5] The surface sizing method according to claim 4, wherein the surface sizing agent is the one according to claim 2 or 3.