JPH11322879A - One-pack moisture-curable polyisocyanate composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject composition free from any organic solvent and having high weatherability and curing rate by compounding a moisture- curing promotive catalyst in a mixture of a low-viscosity isocyanate prepolymer and another isocyanate prepolymer having such a structure as to be liable to set carbon dioxide free. SOLUTION: This composition having a nonvolatile content of >=98 wt.% is obtained by compounding a mixture of (A) an isocyanate prepolymer consisting of a polyisocyanate with aliphatic and/or alicyclic diisocyanate as the basic skeleton and having a viscosity of 50-2,000 mPa.s at 25 deg.C when nonvolatiles accounts for >=98 wt.% of the whole component A and (B) another isocyanate prepolymer prepared by reaction between a polyether polyol 500-10,000 in number-average molecular weight and an excess amount of an aliphatic and/or alicyclic diisocyanate(s) or a polyisocyanate with the above diisocyanate(s) as the basic skeleton, with (C) a moisture-curing promotive catalyst in the weight ratio A/B of (5:95) to (95:5) and in the proportion of the component C, based on the total of the components Aancl B, at 0.005-5 wt.%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to paints, sealers,
The present invention relates to a solvent-free, one-part moisture-curable polyisocyanate composition which is useful as a sealing material, a waterproofing material, and an adhesive, and in which a crosslinking reaction proceeds at room temperature by reacting with moisture (steam) in the air.

[0002]

2. Description of the Related Art It is known that a one-pack moisture-curable polyisocyanate composition using an aliphatic or alicyclic diisocyanate as a raw material is excellent in water resistance, chemical resistance and weather resistance. However, simply using an aliphatic or alicyclic diisocyanate as a raw material results in a liquid having a relatively high viscosity, which may reduce operability during coating. In addition, when the crosslinking reaction proceeds, only the surface of the coating film reacts first, and carbon dioxide generated inside the coating film sometimes remains in the coating film. In order to solve such problems, a one-pack moisture-curable polyisocyanate composition has been used by adding a plasticizer or a solvent.

[0003] However, when a plasticizer is added, components that do not participate in crosslinking remain in the coating film, and performance such as water resistance, solvent resistance, stain resistance, and weather resistance may decrease. . On the other hand, when an organic solvent is added, the working environment may be significantly reduced due to the organic solvent volatilized during the painting operation. Therefore, special equipment such as a painting booth was sometimes required. Furthermore, in recent years, guidelines regarding volatile organic solvents have become strict, and regulations have already been implemented in the United States, Germany, and the like. Therefore, it is desired that the one-component moisture-curable polyisocyanate composition also reduces volatile organic solvents.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a one-part moisture-curable polyisocyanate composition having excellent weather resistance and curing speed and containing no organic solvent.

[0005]

Means for Solving the Problems As a result of diligent studies, the present inventor has found that a moisture curing accelerating catalyst is mixed with a mixture of a low-viscosity isocyanate prepolymer and an isocyanate prepolymer having a structure capable of easily releasing carbon dioxide. As a result, the present inventors have found that the above problem can be solved, and have completed the present invention.

That is, the present invention is as follows. 1] Consisting of the following (A), (B) and (C), wherein the weight ratio of (A) and (B) is 5/95 to 95/5, and (C) with respect to the sum of (A) and (B) ) Is 0.005 to 5% by weight and the non-volatile content is 98% by weight or more. (A) An isocyanate prepolymer comprising a polyisocyanate having an aliphatic and / or alicyclic diisocyanate as a basic skeleton, and having a viscosity at 25 ° C of 50 to 2000 mPa.s when the nonvolatile content is 98% by weight or more. an isocyanate prepolymer that is s. (B) an isocyanate prepolymer obtained by reacting a polyether polyol having a number average molecular weight of 500 to 10,000 with an excess amount of an aliphatic and / or alicyclic diisocyanate or a polyisocyanate having a basic skeleton thereof. (C) Moisture curing acceleration catalyst.

2) It comprises the following (A), (B) and (C), wherein the weight ratio of (A) and (B) is 5/95 to 95/5, and the sum of (A) and (B) The ratio of (C) to 0.
A one-pack moisture-curable polyisocyanate composition having a content of from 005 to 5% by weight and a non-volatile content of 98% by weight or more. (A) An isocyanate prepolymer obtained by reacting a monoalcohol having 1 to 20 carbon atoms with an excess amount of an aliphatic and / or alicyclic diisocyanate or a polyisocyanate having a basic skeleton thereof, When the content is more than 98% by weight, the viscosity at 25 ° C is 50-2000.
mPa. an isocyanate prepolymer that is s. (B) an isocyanate prepolymer obtained by reacting a polyether polyol having a number average molecular weight of 500 to 10,000 with an excess amount of an aliphatic and / or alicyclic diisocyanate or a polyisocyanate having a basic skeleton thereof. (C) Moisture curing acceleration catalyst.

Hereinafter, the present invention will be described in detail. As the aliphatic or alicyclic diisocyanate used in the present invention,
For example, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate (hereinafter, referred to as HDI), trimethylhexamethylene diisocyanate, lysine diisocyanate, isophorone diisocyanate (hereinafter, referred to as IPDI), hydrogenated xylene diisocyanate, 1,4-diisocyanate cyclohexane And 4,4'-dicyclohexylmethane diisocyanate. From the viewpoint of industrial availability, HDI, IPDI, or hydrogenated xylene diisocyanate is preferable, but HDI is most preferable in consideration of the viscosity of the isocyanate prepolymer.

The polyisocyanate having an aliphatic or alicyclic diisocyanate as a basic skeleton in the present invention is
It is an isocyanate prepolymer having a structure such as a buret structure, an isocyanurate structure, a urethane structure, a uretdione structure, an allophanate structure or the like in a molecule. A prepolymer having an isocyanurate structure is capable of forming a coating film having excellent strength and weather resistance, and an isocyanate prepolymer having an allophanate structure and a uretdione structure has a feature that viscosity reduction is easy. Therefore, it is particularly preferable.

In the present invention, the isocyanate prepolymer (A) is a component for lowering the viscosity of the one-pack moisture-curable polyisocyanate composition and for exhibiting hardness when a coating film is formed. The viscosity of the isocyanate prepolymer (A) is 50 to 2000 mPa.s at 25 ° C. in a state substantially free from volatile components. s, preferably 1
00 to 1500 mPa. s, more preferably 200 to 1
000 mPa. s. If the isocyanate prepolymer (A) is a dimer or more, the viscosity is necessarily 50 mP.
a. s or more. 2000 mPa. If it exceeds s, the viscosity of the one-part moisture-curable polyisocyanate composition becomes too high, and the operability at the time of coating may be undesirably reduced.

In the present invention, the non-volatile content is 98% or more,
It is a state that does not substantially contain volatile matter. As a measuring method, for example, about 1.5 g of an isocyanate prepolymer is placed in an aluminum dish having a diameter of 5.5 cm and precisely weighed.
This is placed in an oven at 105 ° C. for 3 hours and then weighed again. The quotient of both measurements is the non-volatile component. The isocyanate prepolymer (A) can also be obtained by reacting a monoalcohol having 1 to 20 carbon atoms with an excess amount of an aliphatic and / or alicyclic diisocyanate or a polyisocyanate having these as a basic skeleton.

The monoalcohol used has 1 to 2 carbon atoms.
It is a monoalcohol having 0, preferably 3 to 15 carbon atoms, and more preferably 6 to 9 carbon atoms. Among monoalcohols, aliphatic or alicyclic alcohols are preferred. Examples of monoalcohols that can be used include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 1-pentanol, 2-pentanol, 1-hexanol, 2-hexanol, cyclohexanol, 4-methyl-cyclohexanol, 1-octanol, 1-nonanol, 2-nonanol, 1-decanol, 2-decanol, 1-tridecanol, seryl alcohol, 2-ethyl-1-hexanol, 5-ethyl-2-nonanol and the like Is mentioned.

The term “excess amount of aliphatic and / or alicyclic diisocyanate” used in the present invention means that the number of moles of diisocyanate is larger than the number of moles of monoalcohol. 5
It is preferably at least 10 times, more preferably at least 10 times. The reaction referred to in the present invention means that a monoalcohol or a polyether polyol is reacted with an aliphatic and / or alicyclic diisocyanate or a polyisocyanate having a basic skeleton thereof, or a urethaneation reaction and an allophanate are performed. Is to carry out the reaction simultaneously.

The isocyanate prepolymer is obtained after the aliphatic or alicyclic diisocyanate is reacted with a monoalcohol having 1 to 20 carbon atoms by a urethanization reaction or an allophanation reaction, or simultaneously with the isocyanuration or uretdionation reaction. It is preferable because the viscosity of (A) can be reduced. In the present invention, when the isocyanate prepolymer (B) is formed into a one-part moisture-curable polyisocyanate coating film,
It is a component for releasing carbon dioxide generated when isocyanate reacts with moisture in the air from the coating film.

The isocyanate prepolymer (B) is obtained by reacting a polyether polyol having a number average molecular weight of 500 to 10,000 with an excess amount of an aliphatic and / or alicyclic diisocyanate or a polyisocyanate having a basic skeleton thereof. can get. The use of the polyether polyol facilitates the penetration of water vapor into the inside of the coating film, and also facilitates the escape of carbon dioxide generated when the isocyanate group reacts with water from the coating film. This is an effect of the structure of the polyether polyol, which easily transmits water vapor and carbon dioxide.

The polyether polyol used in the present invention is, for example, polyethylene glycol, polypropylene glycol or tetrahydrofuran obtained by adding an alkylene oxide such as ethylene oxide or propylene oxide to a polyhydric alcohol such as ethylene glycol, propylene glycol or glycerin. And polytetramethylene ether glycol obtained by ring-opening polymerization.

The number average molecular weight of the polyether polyol used in the present invention is from 500 to 10,000, preferably from 10
It is from 8000 to 8000, more preferably from 2,000 to 8,000. By defining the type and molecular weight of the polyol, the crosslinking density of the coating film becomes appropriate, and a fast curing reaction and a clear and tough coating film can be achieved. That is, it becomes easy for water vapor to penetrate into the inside of the coating film, the curing reaction proceeds quickly, and carbon dioxide generated at the time of the crosslinking reaction easily escapes outside the film. If the molecular weight is less than 500, the crosslink density becomes too large, impeding the penetration of water vapor into the coating and the escape of carbon dioxide out of the coating. This is not appropriate because carbon dioxide bubbles are easily generated. If it exceeds 10,000, the crosslinking density is too low and the coating film becomes brittle, which is not suitable.

Commercially available polyols include PEG1 as polyethylene glycol.
000, PEG2000, PEG4000 (all manufactured by Hodogaya Chemical Co., Ltd.) and polypropylene glycol as PPG1000, PPG2000, PPG400
0 (all manufactured by Hodogaya Chemical Co., Ltd.), Exenol 820, Exenol 840 (all manufactured by Asahi Glass Industry Co., Ltd .; trifunctional polypropylene glycol), PTG1000, PT
G2000, PTG4000 (both manufactured by Hodogaya Chemical Co., Ltd.) and the like.

The isocyanate prepolymer (B) also includes
The same monoalcohol as used in the isocyanate prepolymer (A) may be used in a similar manner. By using the monoalcohol, the viscosity of the isocyanate prepolymer (B) can be reduced, and the operability at the time of coating can be improved. Further, by using the monoalcohol, the compatibility with the polyether polyol is also improved.

The viscosity of the isocyanate prepolymer (B) used in the present invention is 25% when the nonvolatile content is 98% or more.
500-15000 mPa. s is suitable, and preferably 800 to 10000 mPa.s. s, more preferably 1200 to 5000 mPa.s. s. 500 mPa.
s, the carbon dioxide generated in the coating film is apt to remain, and 15000 mPa.s. If it exceeds s, the viscosity of the one-component moisture-curable polyisocyanate composition may be too high, and the operability during coating may be reduced.

The moisture hardening accelerating catalyst (C) used in the present invention is a catalyst for accelerating a reaction for generating a urea group from two isocyanate groups and one water molecule. Such catalysts include, for example, dimethyltin dichloride, dibutyltin dichloride, dioctyltin dichloride,
Organic tin compounds such as monobutyltin trichloride, monobutyltin trialkylate, dibutyltin diacetate, dibutyltin dilaurate, dibutyltin maleate, dibutyltin oxide, dioctyltin oxide, and stannoxy acid-based compounds, tributylamine, tetramethylethylenediamine, tetramethylpropanediamine, Tetramethylhexanediamine, methylmorpholine, dimethylpiperazine, trimethylaminomethylethanolamine, 1,4-diazabicyclo [2,2,2]
Examples thereof include amine compounds such as octane, organic zinc compounds, organic zirconium compounds, and the like, and mixtures thereof.

In the present invention, the weight ratio of the isocyanate prepolymer (A) to the isocyanate prepolymer (B) is 5/95 to 95/5, preferably 10/90 to 9/95.
0/10, more preferably 15/85 to 85/15. When the amount of the isocyanate prepolymer (B) increases beyond 5/95, the viscosity of the moisture-curable polyisocyanate composition increases and the operability at the time of coating decreases, or the hardness of the cured coating film decreases. In some cases, this is not preferable. When the isocyanate prepolymer (A) increases beyond 95/5, carbon dioxide generated during the curing process may remain in the coating film, which is not preferable.

The catalyst for accelerating moisture curing used in the present invention (C)
Is from 0.005 to 5% by weight, preferably from 0.02 to 3% by weight, more preferably from 0.05 to 2% by weight, based on the total amount of the isocyanate prepolymers (A) and (B).
% By weight. If the amount is less than 0.005% by weight, the effect of accelerating the reaction for generating a urea group is not sufficient, so that it is not appropriate. If it exceeds 5% by weight, the pot life is shortened and the storage stability is lowered, so that it is not suitable. Here, the pot life is the pot life of a paint or a sealing material when left in the air.

The one-part moisture-curable polyisocyanate composition of the present invention has a nonvolatile content of 98% by weight or more. 98% by weight or more means that it contains substantially no volatile matter. If the content is less than 98% by weight, volatile components such as organic solvents are released into the air at the time of painting, coating, or forming a coating film, thereby deteriorating the working environment and coating properties such as water resistance, solvent resistance, and weather resistance. May be reduced, which is not preferable.

The viscosity of the one-pack moisture-curable polyisocyanate composition of the present invention at 25 ° C. is 400 to 6000 m
Pa. s is appropriate, and preferably 500 to 4000 m
Pa. s, more preferably 600 to 3000 mPa.s. s
It is. 400 mPa. If it is less than s, carbon dioxide generated when the isocyanate group reacts with water tends to remain in the coating film. If it exceeds s, operability may decrease.

The one-part moisture-curable polyisocyanate composition of the present invention has an isocyanate group content of 6 to 23% by weight.
Is suitable, preferably 7 to 21% by weight, more preferably 8 to 20% by weight. If it is less than 6% by weight, the crosslink density tends to be low and the coating film tends to be brittle. Also, 23
If it exceeds 10% by weight, the crosslink density becomes too large, impeding the penetration of water vapor into the interior of the coating and the escape of carbon dioxide out of the membrane, so that the curing reaction inside the coating slows down. It is easy to generate carbon dioxide bubbles.

The one-part moisture-curable polyisocyanate composition of the present invention is characterized by having high hardness when a coating film is formed. This is achieved by the fact that the components of the polyisocyanate prepolymer (A) create a dense crosslink. If the coating film is too soft, scratches and stains are likely to occur.
When the glass plate is adjusted to 180 with a Koenig hardness tester, it is preferably 20 or more.

The one-part moisture-curable polyisocyanate composition of the present invention is characterized in that carbon dioxide generated during the crosslinking reaction hardly remains as bubbles in the coating film even when the composition is thickly applied. This is achieved because the polyether polyol incorporated in the polyisocyanate prepolymer (B) has a property that the generated carbon dioxide easily escapes out of the membrane. The maximum film thickness where bubbles cannot occur is 200μ
m or more.

The one-pack moisture-curable polyisocyanate composition of the present invention is characterized by a fast curing reaction. This can be achieved due to the use of effective moisture curing catalysts. It is preferable that the time during which the coating film does not become sticky even when touched, that is, the so-called touch-free time is within 24 hours. The one-part moisture-curable polyisocyanate composition of the present invention does not require the addition of a plasticizer used in the field of paints, adhesives, and sealants. Generally, plasticizers are used to reduce viscosity to facilitate handling or to impart softness.However, because components that do not participate in crosslinking enter, the weather resistance, water resistance, and solvent resistance decrease. May be. However, the one-component moisture-curable polyisocyanate of the present invention achieves a low viscosity by the isocyanate prepolymer (A) and a softness by the isocyanate prepolymer (B). There is no.

In the polyisocyanate composition of the present invention, pigments, leveling agents, antioxidants, ultraviolet absorbers, light stabilizers, surfactants and the like are used in the art according to the purpose and application. Various additives can be mixed. Since the polyisocyanate composition of the present invention does not substantially contain a volatile component, the polyisocyanate composition has a feature that the volatile component is not released into the air at the time of painting, applying, or forming a coating film.

The one-component moisture-curable polyisocyanate composition of the present invention has a high coating film hardness and can form a thick coating film.
It has the characteristic that the curing reaction proceeds quickly.
It also has excellent adhesion to metals, especially aluminum, steel plates, glass, plastics, fibers, wood, and other substrates, so paints, sealing materials, waterproofing materials, adhesives, especially metals and metals, and glass and metals , Metal and plastic, glass and glass, plastic and glass, wood and glass, metal and fiber, glass and fiber, plastic and fiber adhesives, and more specifically, mirror backing adhesives, inks,
Coating materials, especially paper, cloth, wood coating materials,
It can be used in a wide range of fields such as casting materials, elastomers and plastic raw materials.

[0032]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be further described below with reference to examples. The measuring method is as shown below. (1) The isocyanate group content (hereinafter, referred to as NCO content) was determined by neutralizing isocyanate groups of the polyisocyanate composition with an excess of amine and then performing back titration with hydrochloric acid.

(2) The viscosity was measured at 25 ° C. and 60 rpm using a digital viscometer (Tokyo Keiki Co., Ltd .; DVM-B type). (3) Non-volatile components were accurately weighed at about 1.5 g of an isocyanate prepolymer or a one-part moisture-curable polyisocyanate composition in an aluminum dish having a diameter of 5.5 cm,
After heating for 3 hours, the isocyanate prepolymer or the one-part moisture-curable polyisocyanate composition after heating was precisely weighed and determined by the following equation.

Non-volatile content (%) = [(weight after heating) /
(Weight before heating)] × 100 (4) The number average molecular weight was determined by using gel permeation chromatography (GPC). When GPC is less than 2,000 (column: Tosoh Corporation; G1000HXL, G200
0HXL, G3000HXL, carrier: THF, detection method: parallax refractometer, data processor: Tosoh Corporation; C
P-8000) and a number average molecular weight of 2,000 or more (Column: Tosoh Corporation; G2000HXL, G400
0HXL, G5000HXL, carrier: THF, inspection method: parallax refractometer, data processor: Tosoh Corporation; C
Chromatocoder 21).

(5) The touch free of the coating film was determined by the time when the surface of the coating film was lightly touched with a finger and the sticky feeling disappeared. The case where the measured value was 6 hours or less was represented by ◎, the case of 6 to 12 hours was represented by ○, the case of 12 to 24 hours was represented by Δ, and the case of exceeding 24 hours was represented by ×. (6) The hardness of the coating film was measured by adjusting the polished glass to 180 using a Koenig hardness meter. When the measured value was 80 or more, it was described as ◎, when it was 40 to 79, it was written as ○, when it was 20 to 39, it was written as Δ, and when it was less than 20, it was written as ×.

[0036]

[Synthesis Example 1 of Isocyanate Prepolymer A] Stirrer,
500 g of HDI was charged into a four-necked flask equipped with a thermometer and a cooling tube, and 0.02 g of tetramethylammonium capryate as an isocyanuration catalyst was added at 70 ° C. Four hours later, when the increase in the refractive index of the reaction solution became 0.010, 0.1 g of phosphoric acid was added to stop the reaction.

Using a falling film thin-film distillation apparatus, the first time of 0.1.
3 Tor. (150 ° C.), 0.2 Tor. To remove unreacted HDI. 115 g of the obtained polyisocyanate prepolymer A had a viscosity of 1300 mPa · s,
The NCO content was 23.1%, and the nonvolatile content was 99.2% by weight.

[0038]

[Synthesis Example 2 of Isocyanate Prepolymer A] Stirrer,
500 g of HDI and 15 g of ethanol were charged into a four-necked flask equipped with a thermometer and a cooling tube, and a urethanization reaction was performed at 90 ° C. for 2 hours with stirring. At 90 ° C., 0.02 g of tetramethylammonium capryate was added as an isocyanuration catalyst. Four hours later, when the increase in the refractive index of the reaction solution reached 0.011, 0.1 g of phosphoric acid was added to stop the reaction.

Using a falling film thin-film distillation apparatus, the first 0.
3 Tor. (150 ° C.), 0.2 Tor. To remove unreacted HDI. 180 g of the obtained polyisocyanate prepolymer A had a viscosity of 800 mPa · s, and N
The CO content was 20.1%, and the nonvolatile content was 99.1% by weight.

[0040]

[Synthesis Example 3 of Isocyanate Prepolymer A] Stirrer,
500 g of HDI and 15 g of 2-ethylhexanol were charged into a four-necked flask equipped with a thermometer and a cooling tube, and a urethanization reaction was performed at 90 ° C. for 2 hours with stirring. At 90 ° C., 0.02 g of tetramethylammonium capryate was added as an isocyanuration catalyst. Four hours later, when the increase in the refractive index of the reaction solution became 0.011, phosphoric acid was added to 0.1 mL.
1 g was added to stop the reaction.

Using a falling thin film distillation apparatus, the first time
3 Tor. (150 ° C.), 0.2 Tor. To remove unreacted HDI. 160 g of the obtained polyisocyanate prepolymer A had a viscosity of 550 mPa · s,
The CO content was 20.7%, and the nonvolatile content was 99.2% by weight.

[0042]

[Synthesis Example 4 of Isocyanate Prepolymer A] Stirrer,
500 g of HDI and 50 g of 2-ethylhexanol were charged into a four-necked flask equipped with a thermometer and a cooling tube, and a urethanization reaction was performed at 90 ° C. for 2 hours with stirring. At 90 ° C., 0.02 g of tetramethylammonium capryate was added as an isocyanuration catalyst. Four hours later, when the increase in the refractive index of the reaction solution becomes 0.015, the phosphoric acid was added to 0.1 mL.
1 g was added to stop the reaction.

Using a falling film thin-film distillation apparatus, the first time of 0.1.
3 Tor. (150 ° C.), 0.2 Tor. To remove unreacted HDI. The obtained polyisocyanate prepolymer A was 236 g and had a viscosity of 450 mPa · s and N
The CO content was 17.8% and the nonvolatile content was 99.3% by weight.

[0044]

[Synthesis Example 5 of Isocyanate Prepolymer A] Stirrer,
500 g of HDI and 50 g of 1-tridecanol were charged into a four-necked flask equipped with a thermometer and a cooling tube, and a urethanization reaction was performed at 90 ° C. for 2 hours with stirring. At 90 ° C., 0.02 g of tetramethylammonium capryate was added as an isocyanuration catalyst. Four hours later, when the increase in the refractive index of the reaction solution became 0.010, 0.1 g of phosphoric acid was added.
Was added to stop the reaction.

Using a falling film thin-film distillation apparatus, the first 0.1.
3 Tor. (150 ° C.), 0.2 Tor. To remove unreacted HDI. The obtained polyisocyanate prepolymer A was 181 g, had a viscosity of 700 mPa · s,
The CO content was 15.5% and the nonvolatile content was 98.9% by weight.

[0046]

[Synthesis Example 6 of Isocyanate Prepolymer A] Stirrer,
500 g of HDI and 25 g of cyclohexanol were charged into a four-necked flask equipped with a thermometer and a condenser, and a urethanization reaction was performed at 90 ° C. for 2 hours with stirring. At 90 ° C., 0.02 g of tetramethylammonium capryate was added as an isocyanuration catalyst. Four hours later, when the increase in the refractive index of the reaction solution became 0.012, 0.1 g of phosphoric acid was used.
Was added to stop the reaction.

Using a falling film thin-film distillation apparatus, the first 0.1.
3 Tor. (150 ° C.), 0.2 Tor. To remove unreacted HDI. 160 g of the obtained polyisocyanate prepolymer A had a viscosity of 1000 mPa · s,
The NCO content was 18.4% and the nonvolatile content was 99.0% by weight.

[0048]

[Synthesis Example 7 of Isocyanate Prepolymer A] Stirrer,
500 g of HDI was charged into a four-necked flask equipped with a thermometer and a cooling tube, and a urethanization reaction was performed at 90 ° C. for 2 hours with stirring. At 90 ° C., 2.5 g of tributylphosphine was added as a uretdionation catalyst. Four hours later, when the increase in the refractive index of the reaction solution became 0.008, 0.35 g of sulfur was used.
Was added to stop the reaction.

Using a falling thin-film distillation apparatus, the first time of 0.1.
3 Tor. (150 ° C.), 0.2 Tor. To remove unreacted HDI. The obtained polyisocyanate prepolymer A was 105 g and had a viscosity of 90 mPa · s.
(25 ° C.), NCO content 23.3%, nonvolatile content is 9
It was 8.5% by weight.

[0050]

[Synthesis Example 1 of Isocyanate Prepolymer B] Stirrer,
HDI in a four-necked flask equipped with a thermometer and cooling tube
, 400 g of IPDI, 100 g of IPDI, and 20 g of PPG2000 (number average molecular weight 2000, manufactured by Hodogaya Chemical)
The urethanization reaction was performed at 90 ° C. for 2 hours with stirring. 90 ° C
Then, 0.03 g of tetramethylammonium capryate was added as an isocyanuration catalyst. Four hours later, when the increase in the refractive index of the reaction solution became 0.010, 0.15 g of phosphoric acid was added to stop the reaction.

Using a falling thin-film distillation apparatus for the first time
3 Tor. (150 ° C.), 0.2 Tor. To remove unreacted HDI. The obtained polyisocyanate prepolymer B had a viscosity of 4500 mPa.s. s, the NCO content was 17.6%, and the nonvolatile content was 98.8% by weight.

[0052]

[Synthesis Example 2 of Isocyanate Prepolymer B] Stirrer,
HDI in a four-necked flask equipped with a thermometer and cooling tube
, 500 g of PPG1000 (20 g of number average molecular weight, manufactured by Hodogaya Chemical Co., Ltd.) and 1.9 g of water.
The biuret reaction was performed at 60 ° C. for 1 hour. Using a falling film thin-film distillation apparatus, the first time of 0.3 Torr. (150 ° C),
Second time 0.2 Torr. To remove unreacted HDI.

The obtained polyisocyanate prepolymer B had a viscosity of 2400 mPa.s. s, NCO content 19.0
% And the nonvolatile content were 98.8% by weight.

[0054]

[Synthesis Example 3 of Isocyanate Prepolymer B] Stirrer,
HDI in a four-necked flask equipped with a thermometer and cooling tube
Was charged with 50 g of 2-ethylhexanol and 47 g of exenol 840 (manufactured by Asahi Glass Co., Ltd., polypropylene glycol, number average molecular weight 6500), and a urethanization reaction was performed at 90 ° C. for 2 hours with stirring. At 90 ° C., 0.02 g of tetramethylammonium capryate was added as an isocyanuration catalyst. Four hours later, when the increase in the refractive index of the reaction solution became 0.015, 0.1 g of phosphoric acid was added.
Was added to stop the reaction.

Using a falling-film thin-film distillation apparatus, the first 0.1.
3 Tor. (150 ° C.), 0.2 Tor. To remove unreacted HDI. The obtained polyisocyanate prepolymer B was 283 g and had a viscosity of 1000 mPa · s,
The NCO content was 14.6%, and the nonvolatile content was 99.2% by weight.

[0056]

[Synthesis Example 4 of Isocyanate Prepolymer] HDI was added to a four-necked flask equipped with a stirrer, a thermometer, and a condenser.
The mixture was charged with stirring at 80 ° C. under stirring at 80 ° C. as tetramethylammonium capryate 0.02 as an isocyanuration catalyst.
g was added. After 4 hours, the increase in the refractive index of the reaction solution is 0.01
When the value reached 0, 0.1 g of phosphoric acid was added to stop the reaction.

Using a falling-type thin film distillation apparatus, the first 0.1.
3 Tor. (150 ° C.), 0.2 Tor. To remove unreacted HDI. 100 g of the obtained polyisocyanate prepolymer was reacted with 200 g of PTG4000 at 120 ° C. for 5 hours to obtain a polyisocyanate prepolymer B. This polyisocyanate prepolymer B
Has a viscosity of 1200 mPa · s, an NCO content of 4.8%,
The nonvolatile content was 98.6% by weight.

[0058]

[Synthesis Example 5 of Isocyanate Prepolymer B] Stirrer,
500 g of HDI and 50 g of 2-ethylhexanol were charged into a four-necked flask equipped with a thermometer and a cooling tube, and a urethanization reaction was performed at 90 ° C. for 2 hours with stirring. At 90 ° C., 0.02 g of tetramethylammonium capryate was added as an isocyanuration catalyst. Four hours later, when the increase in the refractive index of the reaction solution becomes 0.015, the phosphoric acid was added to 0.1 mL.
1 g was added to stop the reaction.

Using a falling-type thin film distillation apparatus, the first 0.1.
3 Tor. (150 ° C.), 0.2 Tor. To remove unreacted HDI. 237 g of the obtained polyisocyanate prepolymer and 94.8 of Exenol 840 were added.
g was reacted at 120 ° C. for 5 hours to obtain a polyisocyanate prepolymer B.

This polyisocyanate prepolymer B
Has a viscosity of 2000 mPa · s and an NCO content of 11.5.
% And the nonvolatile content were 99.1% by weight.

[0061]

Example 1 Synthesis Example 1 of Isocyanate Prepolymer A
20 g of isocyanate prepolymer A synthesized in
80 g of the isocyanate prepolymer B synthesized in Synthesis Example 1 of Isocyanate Prepolymer B and 0.010 g of dibutyltin dichloride were mixed to obtain a moisture-curable polyisosinate composition.

The obtained moisture-curable polyisocyanate composition had a viscosity of 3500 mPa.s. s (25 ° C.), NCO content 19%. The obtained moisture-curable polyisocyanate composition is applied at a thickness of 200 μm, and is applied at 20 ° C. and 65%
When left at RH, a good coating film without bubbles was obtained. Touch free was △. One week later, the hardness of the coating film was measured to be Δ.

[0063]

Examples 2 to 31 and Comparative Examples 1 and 2 In the same manner as in Example 1, the isocyanate prepolymer A, the isocyanate prepolymer B and the moisture curing catalyst were mixed to form a 200 µm coating film. The appearance (whether there are no bubbles or the like), touch-free, and hardness were measured. The results are summarized in Tables 1 and 2.

In the table, dibutyltin dichloride is represented by BTC, dibutyltin diacetate is represented by BTA, dibutyltin dilaurate is represented by BTL, and 1,4-diazabicyclo [2,2,2] octane is represented by DABCO.

[0065]

[Table 1]

[0066]

[Table 2]

[0067]

The one-part moisture-curable polyisocyanate composition of the present invention has a high coating film hardness, can form a thick coating film, has excellent adhesion to a substrate, and contains a volatile organic solvent. It has the feature that it is not. Therefore, it can be used in a wide range of fields such as paints, sealing materials, waterproof materials, adhesives, inks, coating materials, casting materials, elastomers, and plastic raw materials.

Claims (2)

[Claims] 1. It comprises the following (A), (B) and (C),
The weight ratio of (A) and (B) is 5/95 to 95/5,
The ratio of (C) to the sum of (A) and (B) is 0.00
A one-pack moisture-curable polyisocyanate composition having a content of 5 to 5% by weight and a nonvolatile content of 98% by weight or more. (A) An isocyanate prepolymer comprising a polyisocyanate having an aliphatic and / or alicyclic diisocyanate as a basic skeleton, and having a viscosity at 25 ° C of 50 to 2000 mPa.s when the nonvolatile content is 98% by weight or more. an isocyanate prepolymer that is s. (B) an isocyanate prepolymer obtained by reacting a polyether polyol having a number average molecular weight of 500 to 10,000 with an excess amount of an aliphatic and / or alicyclic diisocyanate or a polyisocyanate having a basic skeleton thereof. (C) Moisture curing acceleration catalyst. 2. It comprises the following (A), (B) and (C),
The weight ratio of (A) and (B) is 5/95 to 95/5,
The ratio of (C) to the sum of (A) and (B) is 0.00
A one-pack moisture-curable polyisocyanate composition having a content of 5 to 5% by weight and a nonvolatile content of 98% by weight or more. (A) An isocyanate prepolymer obtained by reacting a monoalcohol having 1 to 20 carbon atoms with an excess amount of an aliphatic and / or alicyclic diisocyanate or a polyisocyanate having a basic skeleton thereof, When the content is more than 98% by weight, the viscosity at 25 ° C is 50-2000.
mPa. an isocyanate prepolymer that is s. (B) an isocyanate prepolymer obtained by reacting a polyether polyol having a number average molecular weight of 500 to 10,000 with an excess amount of an aliphatic and / or alicyclic diisocyanate or a polyisocyanate having a basic skeleton thereof. (C) Moisture curing acceleration catalyst.