JP5071958B2 - Aqueous polyurethane composition - Google Patents

Description

  The present invention is an aqueous polyurethane composition having excellent physical property balance such as chemical resistance, hydrolysis resistance, weather resistance, flexibility, and adhesion, and used for applications such as paints, coating materials, adhesives, and pressure-sensitive adhesives. About.

  Polyurethane emulsion provides a coating film having abrasion resistance, adhesiveness, non-tackiness, rubber elasticity, floor paint, wall agent, paint used for automobiles, etc., or vinyl chloride, ABS resin, metal, glass, It is widely used as an adhesive used for wood and the like, and further as a coating agent used for artificial leather, synthetic leather and the like.

  However, the physical properties of the coating film obtained from the emulsion were not sufficient as compared with the performance obtained from the solvent-based polyurethane resin. In particular, in the case of a polyurethane emulsion using a polyester polyol, there is a problem that the molecular weight decreases during storage of the emulsion in addition to the problem of hydrolysis resistance of the coating film. In addition, when polyether polyol is used, there is a problem that heat resistance becomes a problem, or wear resistance cannot be sufficiently obtained when used for, for example, artificial leather. In order to solve problems such as hydrolysis resistance, heat resistance and abrasion resistance, polyurethane emulsions using polycarbonate diol have been disclosed. Hydrolysis resistance comprising a reaction product of an organic diisocyanate, an amorphous polycarbonate diol, and a urethane prepolymer comprising a compound having one hydrophilic center and at least two isocyanate-reactive groups and a chain extender A polyurethane dispersion that gives a coating film excellent in durability and low-temperature texture is disclosed (see Patent Document 1). An aqueous polyurethane resin composition comprising a polycarbonate diol having a number average molecular weight of 500 to 5,000, a chain extender, an organic diisocyanate, and a neutralizing agent, wherein the polycarbonate diol contains a carboxylic acid-introduced polycarbonate diol. And a paint using the aqueous polyurethane resin composition is disclosed (see Patent Document 2). Water-based emulsion of polyurethane polymer obtained by reacting polyether polyol, polyol selected from polycarbonate diol, chain extender, compound containing carboxyl group and active hydrogen group, organic polyisocyanate, neutralizing agent, The minimum film-forming temperature of the water-based emulsion is less than 35 ° C., the pencil scratch value of the dry film at the measurement temperature of 25 ° C., the strength and elongation at break in the tensile test are 2B or more, 1 to 120 MPa, 100 A polyurethane-based emulsion for water-based paints characterized by ˜1500% is disclosed (see Patent Document 3). Polyisocyanate component comprising diisocyanate as an essential component and other polyisocyanate compound as an optional component, a polycarbonate diol having an average molecular weight of 500 to 50000 and a carboxyl group-containing diol as essential components, and a polyol component comprising other polyol compound as an optional component, A water-dispersed polyurethane composition obtained from an amine component having a monoamine compound as an essential component and a diamine compound as an optional component, a carboxyl group neutralizing agent component and water, and an automotive paint using the water-dispersed polyurethane composition It is disclosed (see Patent Document 4). A urethane resin emulsion comprising a urethane resin obtained from a urethane prepolymer in which at least a part of the terminal is an isocyanate group and an aqueous dispersion medium, wherein the polyurethane resin is 0.5 to 1. A polyurethane resin emulsion containing 0% by weight of carboxyl groups, 2-8% by weight of urethane groups and 0.7-1.1% by weight of urea groups, and having an average particle size of the polyurethane resin of 10 to 500 nm is disclosed. (See Patent Document 5).

However, when the polyurethane emulsion shown above is used, physical properties such as oil resistance, sweat resistance, hydrolysis resistance, weather resistance, flexibility, and adhesion cannot be imparted in a well-balanced manner.
Japanese Patent No. 3151532 JP 10-1110021 A Japanese Patent Laid-Open No. 11-228654 JP 2005-220255 A JP 2005-132961 A

  The present invention is a water-based polyurethane used for applications such as paints, coating materials, adhesives, pressure-sensitive adhesives, etc., which has an excellent balance of physical properties such as oil resistance, sweat resistance, hydrolysis resistance, weather resistance, flexibility and adhesion. An object is to provide a composition.

  As a result of intensive studies to solve the above problems, the present inventor has found that the above problems can be solved by using a specific polycarbonate diol, and has led to the present invention.

（式中、Ｒ_１は、２−メチル−１，３プロパンジオールに由来するアルキレン基を除く、炭素数２〜２０のアルキレン基を表す。）
（２）上記式（Ｂ）中のＲ_１が下記式（Ｃ）で表されることを特徴とする（１）に記載の水性ポリウレタン組成物。
（ＣＨ_２）ｎ （Ｃ）
（式中、ｎは、２〜１０の整数を表す。）
（３）上記式（Ｂ）中のＲ_１が下記式（Ｄ）で表されることを特徴とする（１）に記載の水性ポリウレタン組成物。
（ＣＨ_２）ｍ （Ｄ）
（式中、ｍは、４または６の整数を表す。）に関するものである。 That is, the present invention
Reaction of urethane prepolymer comprising (1) (a) organic isocyanate, (b) polycarbonate diol, and (c) a compound having one hydrophilic center and at least two isocyanate-reactive groups with a chain extender The polycarbonate diol of (b) contains a repeating unit of the following formula (A) and the following formula (B), the terminal group is a hydroxyl group, and the ratio of (A) and (B) is a molar ratio. 99: 1-1: 99, an aqueous polyurethane composition characterized in that it is a polycarbonate diol having a number average molecular weight of 300-10000,

(In the formula, R ₁ represents an alkylene group having 2 to 20 carbon atoms excluding an alkylene group derived from 2-methyl-1,3-propanediol.)
(2) an aqueous polyurethane composition according to R ₁ in the formula (B) is characterized by being represented by the following formula (C) (1).
(CH ₂ ) n (C)
(In the formula, n represents an integer of 2 to 10.)
(3) R < ₁ > in the said formula (B) is represented by following formula (D), The aqueous polyurethane composition as described in (1) characterized by the above-mentioned.
(CH ₂ ) m (D)
(Wherein m represents an integer of 4 or 6).

  The present invention is an aqueous polyurethane composition used for applications such as paints, coating materials, adhesives, and pressure-sensitive adhesives, which have excellent physical property balance such as oil resistance, sweat resistance, hydrolysis resistance, weather resistance, flexibility and adhesion. You can provide things.

  Hereinafter, the present invention will be specifically described.

  The organic isocyanate used in the present invention is 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate and mixtures thereof, diphenylmethane-4,4′-diisocyanate (MDI), naphthalene-1,5-diisocyanate (NDI), Aromatic diisocyanates such as 3,3′-dimethyl-4,4′biphenylene diisocyanate (TODI), crude TDI, polymethylene polyphenylene polyisocyanate (PMDI), crude MDI, dianidin diisocyanate, tetramethylxylylene diisocyanate, xylylene diisocyanate (XDI), aromatic aliphatic diisocyanates such as p-phenylene diisocyanate, 4-4'-methylenebiscyclohexyl diisocyanate (hydrogenated MDI), isophorone diisocyanate IPDI), cyclohexane diisocyanate (hydrogenated XDI), cycloaliphatic diisocyanates such as norbornene diisocyanate, hexamethylene diisocyanate (HDI), 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, Mention may be made of aliphatic diisocyanates such as cidin isocyanate. It is preferable to use an alicyclic diisocyanate or an aliphatic diisocyanate from the viewpoint of reducing light resistance, and it is more preferable to use an alicyclic diisocyanate from the viewpoint of hydrolysis resistance. The organic isocyanate may be used in the form of a modified product such as carbodiimide modification, isocyanurate modification, biuret modification or the like, or may be blocked isocyanate blocked with various blocking agents. Usually, one type of organic isocyanate is selected and used, but two or more types may be selected from these organic isocyanates, and these may be mixed or sequentially added. Furthermore, a polyisocyanate having 3 or more isocyanate groups in one molecule can also be used. Examples of polyisocyanates having 3 or more isocyanate groups in one molecule include triphenylmethane triisocyanate, 1-methylbenzol, in addition to the above-mentioned isocyanurate trimers, biuret trimers, and trimethylolpropane adduct compounds of diisocyanate. -2,4,6-triisocyanate, dimethyltriphenylmethane tetraisocyanate and the like. Further, these may be used in the form of modified products such as isocyanurate modification and biuret modification, or may be used in the form of blocked isocyanate blocked with various blocking agents.

  In the present invention, the compounding amount of the organic isocyanate is 70 to 100 based on the total of the isocyanate-reactive groups of the compound having a hydroxyl group, one hydrophilic center and at least two isocyanate-reactive groups of the polycarbonate diol. % Equivalent, preferably 80-98% equivalent. When the blending amount of organic isocyanate is less than 70% equivalent, the molecular weight of urethane is small and the strength after curing is often insufficient, and when it exceeds 100% equivalent, excess isocyanate groups remain, so gel during storage This causes a problem in storage stability and the like, and is not preferable.

  The polycarbonate diol used in the present invention can be obtained by subjecting it to transesterification using diol and carbonate as raw materials.

  The polycarbonate diol used in the present invention uses a diol represented by the following formula (E) and the following formula (F) as a raw material.

（式中、Ｒ_１は、２−メチル−１，３プロパンジオールに由来するアルキレン基を除く、炭素数２〜２０のアルキレン基を示す。）
上記式（Ｆ）で表されるジオールは、２−メチルー１，３−プロパンジオールを除くジオールであって、その例としては、エチレングリコール、１，３−プロパンジオール、１，４−ブタンジオール、１，５−ペンタンジオール、１，６−ヘキサンジオール、１，７−ヘプタンジオール、１，８−オクタンジオール、１，９−ノナンジオール、１，１０−デカンジオール、１，５−ヘキサンジオール、２−メチル−１，８−オクタンジオール、ネオペンチルグリコール、２−イソプロピル−１，４−ブタンジオール、２−エチル−１，６−ヘキサンジオール、３−メチル−１，５−ペンタンジオール、２，４−ジメチル−１，５−ペンタンジオール、２，４−ジエチル−１，５−ペンタンジオール、１，３−ブタンジオール、２−エチルー１，３−ヘキサンジオール、２−ブチル−２−エチル−１，３−プロパンジオール、１，３−シクロヘキサンジオール、１，４−シクロヘキサンジオール、１，４−シクロヘキサンジメタノール、２−ビス（４−ヒドロキシシクロヘキシル）−プロパンなどを挙げることができる。上記式（Ｆ）で表されるジオールは、１種類のみを用いても２種以上を併用しても良い。なかでも、炭素数２〜１０の直鎖アルキレンジオールを用いるのが好ましい。１，３−プロパンジオール、１，４−ブタンジオール、１，５−ペンタンジオール、１，６−ヘキサンジオールを用いることがより好ましい。さらに、強度に優れるという観点では、１，４−ブタンジオール、１，６−ヘキサンジオールを用いることが好ましい。

(In the formula, R ₁ represents an alkylene group having 2 to 20 carbon atoms excluding an alkylene group derived from 2-methyl-1,3-propanediol.)
The diol represented by the above formula (F) is a diol excluding 2-methyl-1,3-propanediol, and examples thereof include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,5-hexanediol, 2 -Methyl-1,8-octanediol, neopentyl glycol, 2-isopropyl-1,4-butanediol, 2-ethyl-1,6-hexanediol, 3-methyl-1,5-pentanediol, 2,4 -Dimethyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, 1,3-butanediol, 2-ethyl-1 3-hexanediol, 2-butyl-2-ethyl-1,3-propanediol, 1,3-cyclohexanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, 2-bis (4-hydroxycyclohexyl) ) -Propane and the like. The diol represented by the above formula (F) may be used alone or in combination of two or more. Especially, it is preferable to use a C2-C10 linear alkylene diol. More preferably, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, and 1,6-hexanediol are used. Furthermore, from the viewpoint of excellent strength, it is preferable to use 1,4-butanediol and 1,6-hexanediol.

  As for the polycarbonate diol used by this invention, the ratio of the said Formula (A) and the said Formula (B) is 99: 1 to 1:99 by molar ratio. Preferably, it is 80: 20-20: 80. More preferably, it is 70: 30-30: 70.

  In addition to (E) and (F), the polycarbonate diol used in the present invention includes compounds having three or more hydroxyl groups per molecule, such as trimethylolethane, trimethylolpropane, hexanetriol, penta Polyfunctionalized polycarbonates by using a small amount of erythritol and the like are also included. If too many compounds having three or more hydroxyl groups in one molecule are used, gelation occurs due to crosslinking, so the amount is made 5 mol% or less with respect to the total number of moles of diol. Preferably, it is 2 mol% or less.

  The range of the average molecular weight of the polycarbonate used in the present invention is 300 to 10,000, preferably 400 to 5000, and more preferably 400 to 2500 in terms of number average molecular weight.

  The polycarbonate diol used in the present invention uses a carbonate ester such as alkylene carbonate, dialkyl carbonate, diaryl carbonate or the like as a raw material. Examples of the alkylene carbonate include ethylene carbonate, trimethylene carbonate, 1,2-propylene carbonate, 1,2-butylene carbonate, 1,3-butylene carbonate, and 1,2-pentylene carbonate. Examples of the dialkyl carbonate include dimethyl carbonate, diethyl carbonate, and di-n-butyl carbonate, and examples of the dialkylene carbonate include diphenyl carbonate. Among these, it is preferable to use ethylene carbonate, dimethyl carbonate, or diethyl carbonate. More preferably, ethylene carbonate is used.

  In this invention, the reaction temperature at the time of performing transesterification is 120 to 280 degreeC. Preferably, it is 130 degreeC-230 degreeC.

  When obtaining the polycarbonate diol used in the present invention, it is desirable to use a catalyst when it is desired to speed up the reaction. As a catalyst, it can select and use from the transesterification catalyst used normally. Examples of the transesterification reaction catalyst include titanium compounds such as tetraisopropoxy titanium and tetra-n-butoxy titanium, tin compounds such as di-n-butyltin dilaurate, di-n-butyltin oxide and dibutyltin diacetate, magnesium acetate, and calcium acetate. And metal salts of acetic acid such as zinc acetate. Of these, it is preferable to use a titanium compound. These catalysts are preferably used in an amount of 1 to 300 ppm based on the reaction product. It is more preferable to use it so that it may become 30-200 ppm.

The polycarbonate diol used in the present invention may have an ether bond in the molecule for the purpose of improving flexibility. The content of the ether bond is not particularly limited as long as it does not affect the effects of the present invention, but heat resistance and chemical resistance decrease as the amount increases. Therefore, the content of the ether bond is preferably 0.05 to 5 mol%, and more preferably 0.05 to 3 mol%.
Moreover, polyether polyol or polyester polyol can also be used together in the aqueous polyurethane composition of the present invention as long as the effects of the present invention are not impaired. However, when the polyester polyol is added, the hydrolysis resistance is often remarkably lowered, so that its use is limited.

The compound having one hydrophilic center and at least two isocyanate-reactive groups used in the present invention is used to introduce an anionic hydrophilic group for the purpose of maintaining the emulsion stability of the polyurethane emulsion. Component.
For example, 2-hydroxylpropionic acid, 2,2-dimethylolbutyric acid, dihydroxycarboxylic acid such as 2,2-dimethylolvaleric acid, 3,4-diaminobutanesulfonic acid, 3,6-diamino-2-toluenesulfonic acid, etc. The diaminocarboxylic acids can be used.

When a compound having one hydrophilic center and at least two isocyanate-reactive groups is used, it is usually neutralized with a neutralizing agent from the viewpoint of emulsion stability. Examples of neutralizing agents include trialkylamines such as trimethylamine, triethylamine, tri-n-propylamine, tributylamine, N, N-dimethylethanolamine, N, N-dimethylpropanolamine, N, N-dipropylethanol. Amines, N, N-dialkylalkanolamines such as 1-dimethylamino-2-methyl-propanol, N-alkyl-N, N-dialkanolamines, trialkanolamines such as triethanolamine, sodium hydroxide, potassium hydroxide Lithium hydroxide, ammonia, trimethylammonium hydroxide, and the like. The amount of the neutralizing agent is 0.5 to 2.0 equivalents, preferably 0.7 to 1.2 equivalents, relative to the number of moles of the hydrophilic center.

  Examples of the chain extender used in the present invention include water, short-chain diols such as ethylene glycol and 1,4-butanediol, hydrazine, ethylenediamine, diethyltriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, propylenediamine, Hexamethylenediamine, cyclohexylenediamine, piperazine, 2-methylpiperazine, phenylenediamine, tolylenediamine, xylenediamine, α, α'-methylenebis (2-chloranilin), 3,3'-dichloro-α, α'- And polyamines such as biphenylamine, m-xylenediamine, isophoronediamine, N-methyl-3,3′-diaminopropylamine, and adducts of diethylenetriamine and acrylate or hydrolysis products thereof. . The amount of chain extender is usually 0 per mole of isocyanate groups in a urethane prepolymer comprising an organic isocyanate, a polycarbonate diol, and a compound having one hydrophilic center and at least two isocyanate-reactive groups. -0.95 mol, preferably 0.1-0.6 mol.

  To ensure emulsion stability, anionic surfactants, nonionic surfactants, cationic surfactants, amphoteric surfactants, polymeric surfactants, reactive surfactants, etc., commonly used in emulsions Can be used. Examples of nonionic surfactants include aliphatic alcohol alkylene oxide adducts, alkylphenol alkylene oxide adducts, polyhydric alcohol fatty acid esters such as sorbitan monolaurate, fatty acid alkanolamides such as coconut oil fatty acid diethanolamide, (poly And dialkylamine oxides such as (oxy) alkylene alkylphenyl ether, (poly) oxyalkylene alkylamine, and lauryldimethylamine oxide. Anionic surfactants include ether carboxylic acids or salts thereof such as sodium lauryl ether acetate, sulfate esters or salts thereof such as sodium lauryl sulfate, (poly) oxyethylene sodium lauryl sulfate, (poly) oxyethylene lauric acid triethanol Examples include amines, sulfonates such as sodium dodecylbenzenesulfonate, phosphate esters such as sodium lauryl phosphate or salts thereof, and fatty acid salts such as sodium laurate. Examples of the cationic activator include primary to tertiary amine salts, pyridinium salts, alkylpyridinium salts, and the like. The above surfactants can be used in any amount as required, but are usually usually organic isocyanates, polycarbonate diols, and one hydrophilic center and at least two isocyanate-reactive groups. It is used in an amount of 0.1 to 30% by weight, preferably 3 to 20% by weight, based on the combined weight of the urethane prepolymer composed of the compound having a chain extender.

  In the process of producing the aqueous polyurethane composition of the present invention, an organic solvent may be used as necessary. The organic solvent may be any solvent inert to the isocyanate. Examples include ketones such as methyl ethyl ketone and acetone, ketones such as methyl acetate and ethyl acetate, acetonitrile, tetrahydrofuran, toluene, dioxane, and N-methylpyrrolidone. These can be used alone or in admixture of two or more. When the boiling point of the organic solvent exceeds 100 ° C., that is, exceeds the boiling point of water, it becomes difficult to completely remove only the organic solvent, and it tends to remain in the emulsion or the coating film. Problems such as change to. Therefore, it is preferable to use an organic solvent having a boiling point of 100 ° C. or lower. When an organic solvent is used, it is used in an amount of 3 to 100% by weight based on the weight of the organic isocyanate, polycarbonate diol, compound having one hydrophilic center and at least two isocyanate-reactive groups and the chain extender. The

  In the process of producing the aqueous polyurethane composition of the present invention, a known catalyst may be used as necessary. Examples of the catalyst include amines such as triethylamine, N-ethylmorpholine, and triethylenediamine, tin compounds such as dibutyltin dilaurate, dioctyltin dilaurate, and tin octylate, and titanium compounds such as tetrabutyltitanate.

  In the aqueous polyurethane composition of the present invention, a necessary amount of commonly used additives can be added depending on the application. Additives include pigments, dyes, light stabilizers, auxiliary binders, thickeners, leveling agents, thixotropy imparting agents, antifoaming agents, foaming agents, ultraviolet absorbers, antioxidants, thickeners, film forming aids. , Curing agent, silane coupling agent, anti-blocking agent, anti-gelling agent, dispersion stabilizer, radical scavenger, inorganic or organic filler, plasticizer, lubricant, antistatic agent, antibacterial agent, fungicide, antiseptic Etc.

  The state of the aqueous polyurethane composition of the present invention is an emulsion, suspension, colloidal dispersion or the like. In the case of an emulsion, suspension, or colloidal dispersion, the particle size is not particularly limited, but is preferably 1 μm or less and more preferably 500 nm or less for the purpose of maintaining a good dispersion state.

  In the aqueous polyurethane composition of the present invention, the solid content is not particularly limited. Usually, it is 10 to 70% by weight, preferably 20 to 60% by weight.

  The method for producing the aqueous polyurethane composition of the present invention is not particularly limited, and examples thereof include the following methods. In the presence of an organic solvent, a polycarbonate diol, one hydrophilic center and at least two isocyanate-reactive compounds are reacted with an organic isocyanate to produce a urethane prepolymer whose terminal is an isocyanate. The urethane prepolymer is put into a chain extender-containing aqueous solution, emulsified and subjected to a chain extension reaction, and then the organic solvent contained in the system is removed by a method such as distillation to obtain a urethane emulsion. The neutralizing agent may be used in the process of producing the urethane prepolymer, may be added before the urethane prepolymer is produced, and before being added to the chain extender-containing aqueous solution, or may be added to the chain extender-containing aqueous solution. . The reaction is usually carried out at 20 to 90 ° C.

  Next, the present invention will be described with reference to examples and comparative examples.

Values shown in the following examples and comparative examples were measured by the following methods.
a) Hydroxyl value of polycarbonate diol Using a measuring flask, pyridine is added to 12.5 g of acetic anhydride to make 50 ml, and an acetylating reagent is prepared. A sample is accurately weighed in an amount of 2.5 to 5.0 g in a 100 ml eggplant flask. Add 5 ml of acetylating reagent and 10 ml of toluene with a whole pipette, attach a condenser, and stir and heat at 100 ° C. for 1 hr. Add 2.5 ml of distilled water with a whole pipette and stir for 10 min. After cooling for 2 to 3 minutes, 12.5 ml of ethanol is added, and after adding 2-3 drops of phenolphthalein as an indicator, titration is performed with 0.5 mol / l ethanolic potassium hydroxide. 5 ml of an acetylating reagent, 10 ml of toluene, and 2.5 ml of distilled water are placed in a 100 ml eggplant flask and stirred for 10 minutes, and then titrated in the same manner (blank test). Based on this result, the hydroxyl value was calculated by the following formula (1).

Hydroxyl value (mg-KOH / g) = {(BA) × 28.05 × f} / C (1)
A: Titration volume of sample (ml)
B: Titrate of blank test (ml)
C: Sample weight (g)
f: Factor of titrant The polymer ends in Examples and Comparative Examples were substantially all hydroxyl groups as determined by ¹³ C-NMR (270 MHz). Furthermore, although the acid value in a polymer was measured by titration with KOH, all of the polymers of Examples and Comparative Examples were 0.01 or less. Therefore, the number average molecular weight of the obtained polymer is obtained by the following formula (2) using the above hydroxyl value.
Number average molecular weight = 2 / (hydroxyl value × 10 ⁻³ /56.11) (2)
b) Composition ratio of polycarbonate diol The composition ratio was measured as follows. Take 1 g of a sample in a 100 ml eggplant flask, add 30 g of ethanol and 4 g of potassium hydroxide, and react at 100 ° C. for 1 hr. After cooling to room temperature, add 2-3 drops of phenolphthalein to the indicator and neutralize with hydrochloric acid. After cooling in the refrigerator for 1 hr, the precipitated salt was removed by filtration and analyzed by gas chromatography. The analysis was performed by using gas chromatography GC-14B (manufactured by Shimadzu Corporation) with DB-WAX (manufactured by J & W) as a column, diethylene glycol diethyl ester as an internal standard, and a detector as FID. The temperature rising profile of the column was maintained at 60 ° C. for 5 minutes and then heated to 250 ° C. at 10 ° C./min. Based on the obtained results, the composition ratio was determined using the following formula (3).
Composition ratio (mol%) = (D / E) × 100 (3)
D: Number of moles of 2-methyl-1.3-propanediol
E: Number of moles of all diols When the polycarbonate diol has an ether bond in the molecule, the content is the number of moles of diol having an ether bond with respect to the number of moles of all diols obtained by the above method. Expressed as a percentage.
c) Film preparation After storing the emulsion at 40 ° C. for 1 month, the film was formed on a glass plate, allowed to stand at room temperature for 24 hours, and then heat-treated at 120 ° C. for 30 minutes, having a thickness of 100 μm, a width of 10 mm, and a length of 60 mm. A sample film was obtained. The film obtained by the above method was used to evaluate oil resistance, hydrolysis resistance, weather resistance, and flexibility.
d) Mechanical strength Measurement was performed in a constant temperature room using a Tensilon tensile tester (manufactured by ORIENTEC, RTC-1250A) at a chuck distance of 50 mm and a tensile speed of 100 mm / min. The strength at break was defined as mechanical strength (hereinafter referred to as strength).
e) Oil resistance The swelling ratio after the sample was immersed in 45 ° C. oleic acid (reagent grade 1) for 1 week was measured. The swelling rate was determined using the following formula (4).

Swelling ratio = (weight after test−weight before test) / weight before test × 100 (4)
f) Hydrolysis resistance After immersing the sample in hot water at 100 ° C. for 2 weeks, the mechanical strength was measured by the method shown in d) above. When the measured value after the test is 80% or more compared to the value obtained from the sample before the test, the case where the measured value is 60% or more and less than 80% is Δ, and the case where the measured value is less than 60% is ×. The hydrolyzability was evaluated.
g) Weather resistance After a predetermined time (200 hours) has elapsed in a sunshine type weatherometer (WEL-SUN-DC, manufactured by Suga Test Instruments Co., Ltd.) and repeated precipitation for 12 minutes within 60 minutes, d above ) Was used to measure the mechanical strength. When the value after measurement was 80% or more compared to the value before the test, the weather resistance was evaluated with ◯ when the value was 60% or more and less than 80%, and x when the value was less than 60%. .
h) Flexibility The mechanical strength was measured by the method shown in d) above, and the flexibility was evaluated by the stress (MPa) when the sample was stretched 100%.
[Synthesis Example 1 of Polycarbonate Diol]

A 2 l separable flask equipped with a stirrer, thermometer, Oldershaw with vacuum jacket having a reflux head at the top was charged with 355 g of 2-methyl-1,3-propanediol, 305 g of 1,4-butanediol, and 650 g of ethylene carbonate, After stirring and dissolving at 70 ° C., 0.015 g of lead acetate trihydrate was added as a catalyst. The mixture was heated in an oil bath set at 165 ° C., and the reaction was carried out for 24 hours while extracting a part of the fraction from the reflux head at a reflux ratio of 4 at an internal temperature of the flask of 135 ° C. and a vacuum of 1.0 to 1.5 kPa. Thereafter, the Oldershaw was replaced with a simple distillation apparatus, heated in an oil bath set at 180 ° C., the internal temperature of the flask was reduced to 140 to 150 ° C., the degree of vacuum was reduced to 0.5 kPa, and the diol remaining in the separable flask and Ethylene carbonate was removed. Then, the setting of the oil bath was raised to 175 ° C., and the reaction was further performed for 12 hours while removing the diol produced at an internal temperature of the flask of 150 to 155 ° C. By this reaction, a viscous liquid was obtained at room temperature. The obtained reaction product had a hydroxyl value of 55.7 and a composition ratio of 50 mol%. This polycarbonate diol is referred to as PC1.
[Synthesis Example 2 of Polycarbonate Diol]

Using the apparatus of Synthesis Example 1, 702 g of 1,6-hexanediol, 524 g of ethylene carbonate, and 0.012 g of lead acetate trihydrate were charged. The mixture was heated in an oil bath set at 180 ° C., and the reaction was carried out for 20 hours while extracting a part of the fraction from the reflux head at a reflux ratio of 4 at an internal temperature of the flask of 155 ° C. and a degree of vacuum of 3.0 to 4.2 kPa. Thereafter, the Oldershaw was replaced with a simple distillation apparatus, and then heated in an oil bath set at 190 ° C., and the flask was left in a separable flask with an internal temperature of 160 to 170 ° C. and a vacuum reduced to 0.5 kPa. Diol and ethylene carbonate were removed. Thereafter, the reaction was further carried out for 12 hours while removing the produced diol. By this reaction, a white solid was obtained at room temperature. The obtained reaction product had a hydroxyl value of 56.3. This polycarbonate diol is referred to as PC2.
[Synthesis Example 3 of Polycarbonate Diol]

Polymerization was performed under the conditions of Synthesis Example 2 except that 530 g of 1,6 hexanediol, 150 g of 1,5-pentanediol, 524 g of ethylene carbonate, and 0.011 g of lead acetate trihydrate were used. By this reaction, a viscous liquid was obtained at room temperature. The obtained reaction product had a hydroxyl value of 56.8. This polycarbonate diol is referred to as PC3.
[Synthesis Example 4 of Polycarbonate Diol]

Using the apparatus of Synthesis Example 1, 178 g of 1,6-hexanediol, 394 g of 2-methyl-1,3-propanediol, 520 g of ethylene carbonate, and 0.012 g of lead acetate trihydrate were charged. The mixture was heated in an oil bath set at 185 ° C., and the reaction was carried out for 20 hours while removing a part of the fraction from the reflux head at a reflux ratio of 4 at an internal temperature of the flask of 160 ° C. and a degree of vacuum of 3.2 to 4.5 kPa. Thereafter, the Oldershaw was replaced with a simple distillation apparatus, and then heated in an oil bath set at 190 ° C., and the flask was left in a separable flask with an internal temperature of 160 to 170 ° C. and a vacuum reduced to 0.5 kPa. Diol and ethylene carbonate were removed. Thereafter, the reaction was further carried out for 11 hours while removing the diol produced. By this reaction, a viscous liquid was obtained at room temperature. The obtained reaction product had a hydroxyl value of 55.8 and a composition ratio of 69 mol%. The polycarbonate diol is referred to as PC4 [Polycarbonate diol synthesis example 5]

  Polymerization was performed under the conditions of Synthesis Example 4 except that 358 g of 1,5-pentanediol, 104 g of 2-methyl-1,3-propanediol, 405 g of ethylene carbonate, and 0.010 g of lead acetate trihydrate. By this reaction, a viscous liquid was obtained at room temperature. The obtained reaction product had a hydroxyl value of 57.0 and a composition ratio of 21 mol%. This polycarbonate diol is referred to as PC5.

Example 1
In a reaction vessel equipped with a reflux condenser, a thermometer, and a stirrer, polycarbonate diol PC (1200 g), 4,4′-diphenylmethane diisocyanate (hereinafter referred to as MDI) 74.5 g, and triethylamine (hereinafter referred to as TMA). 23.5 g of summed dimethylolpropionic acid (hereinafter referred to as DMPA) and 730 g of methyl ethyl ketone (hereinafter referred to as MEK) were added and reacted at 50 ° C. for 2 hours to obtain a urethane prepolymer having a terminal isocyanate. . After setting the temperature in the reaction vessel to 30 ° C., 680 g of distilled water was added to the urethane prepolymer at a rate of 20 g / min while stirring to obtain an emulsion of a urethane prepolymer solution. Furthermore, 67.5 g of a 20 wt% aqueous solution of isophoronediamine (hereinafter referred to as IPDA) was added as a chain extender over 30 minutes with stirring. Thereafter, the temperature in the reaction vessel was set to 40 ° C., and the reaction was further continued for 30 minutes. After changing the reflux condenser to a simple distillation apparatus, MEK as a solvent was distilled off while raising the internal temperature of the reaction vessel to 80 ° C. under reduced pressure over 3 hours, and the solid content was about 30% by weight. An aqueous polyurethane composition was obtained. This aqueous polyurethane composition is referred to as PUD1.

Comparative Examples 1-2
By the method shown in Example 1, an aqueous polyurethane composition was obtained using polycarbonate diol PC2 and polycarbonate diol PC3. The aqueous polyurethane composition using polycarbonate diol PC2 is referred to as PUD2, and the aqueous polyurethane composition using polycarbonate diol PC3 is referred to as PUD3.

Examples 2-3
By the method shown in Example 1, an aqueous polyurethane composition was obtained using polycarbonate diol PC4 and polycarbonate diol PC5. The aqueous polyurethane composition using polycarbonate diol PC4 is referred to as PUD4, and the aqueous polyurethane composition using polycarbonate diol PC5 is referred to as PUD5.

  Table 1 below shows the amounts of the isocyanate and the like used in the above examples and comparative examples.

  It can be used for applications such as paints, coating materials, adhesives, and pressure-sensitive adhesives that have excellent balance of physical properties such as chemical resistance, hydrolysis resistance, weather resistance, flexibility, and adhesion.

Claims (3)

From a reaction product of a urethane prepolymer and a chain extender comprising (a) an organic isocyanate, (b) a polycarbonate diol, and (c) a compound having one hydrophilic center and at least two isocyanate-reactive groups. The polycarbonate diol of (b) contains repeating units of the following formula (A) and the following formula (B), the terminal group is a hydroxyl group, and the ratio of (A) and (B) is 99: 1 in molar ratio. An aqueous polyurethane composition characterized by being a polycarbonate diol having a number average molecular weight of 300 to 10,000 at ˜1: 99.

(In the formula, R ₁ represents an alkylene group having 2 to 20 carbon atoms, excluding an alkylene group derived from 2-methyl-1,3-propanediol) The aqueous polyurethane composition according to claim 1, wherein R ₁ in the formula (B) is represented by the following formula (C).
(CH ₂ ) n (C)
(In the formula, n represents an integer of 2 to 10.) The aqueous polyurethane composition according to claim 1, wherein R ₁ in the formula (B) is represented by the following formula (D).
(CH ₂ ) m (D)
(In the formula, m represents an integer of 4 or 6.)