JPH107757A - One-pack moisture-curing polyisocyanate composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a one-peak moisture-curing polyisocyanate composition which has an excellent weatherability and a long pot life and cures rapidly. SOLUTION: The composition is obtained by reacting a polyether polyol and/or a polyester polyol each having a number-average mol.wt. of 300-8,000 with an excess of an aliphatic and/or alicyclic diisocyanate or a polyisocyanate having a backbone formed from the diisocyanate to produce a polyisocyanate prepolymer, and mixing the prepolymer with a moisture-curing catalyst, e.g. dibutyltin dilaurate, in a weight ratio of 100/(0.005-2).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a one-part moisture-curable polyisocyanate which is cured by reacting with moisture in the air, has excellent weather resistance and curing speed, and is used as a paint, a sealing material, a waterproofing material and an adhesive. The present invention relates to a useful one-part moisture-curable polyisocyanate composition.

[0002]

2. Description of the Related Art Conventionally, a one-pack moisture-curable polyisocyanate composition using an aromatic diisocyanate as a raw material has been
It is widely known that they have excellent water resistance, chemical resistance and the like. However, the use of aromatic isocyanates in applications requiring weather resistance has been limited due to the characteristic of yellowing due to light.

[0003] Polyisocyanates prepared from aliphatic or alicyclic diisocyanates react more slowly with water than aromatic polyisocyanates. It took a long time to cure, and the utility was extremely low.

[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 excellent curing speed.

[0005]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that the above-mentioned problems can be solved by mixing a moisture-curing accelerating catalyst with an aliphatic or alicyclic polyisocyanate prepolymer having a specific structure. Have been found, and the present invention has been completed. That is, the present invention relates to a polyether obtained by reacting a polyether polyol and / or polyester polyol having a number average molecular weight of 300 to 8000 with an excess amount of an aliphatic and / or alicyclic diisocyanate or a polyisocyanate having these as a basic skeleton. The present invention relates to a one-pack moisture-curable polyisocyanate composition obtained by mixing an isocyanate prepolymer and a moisture curing-promoting catalyst in an amount of 0.005 to 2% by weight based on the polyisocyanate prepolymer.

[0006] The polyether polyol used in the present invention is, for example, polyethylene glycol, polypropylene glycol or the like 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. Examples include polytetramethylene ether glycol obtained by ring-opening polymerization of tetrahydrofuran.

The polyester polyol used in the present invention includes, for example, carboxylic acids such as succinic acid, adipic acid, sebacic acid, dimer acid, maleic anhydride, phthalic anhydride, isophthalic acid and terephthalic acid, and ethylene glycol and propylene. Glycol, diethylene glycol, neopentyl glycol, trimethylolpropane, polyester polyol obtained by a condensation reaction with a polyhydric alcohol such as glycerin, and, for example, polycaprolactone obtained by ring-opening polymerization of ε-caprolactam using a polyhydric alcohol Polyols.

Commercially available polyols include PEG as polyethylene glycols.
400, PEG1000, PEG2000 (all manufactured by Hodogaya Chemical Co., Ltd.), as polypropylene glycols, PPG1000, PPG4000 (all manufactured by Hodogaya Chemical Co., Ltd.), Exenol 820, Exenol 840 (all manufactured by Asahi Glass Industry Co., Ltd., trifunctional PTG1000, PTG2000 as polypropylene glycol) and polytetramethylene glycols
(Both manufactured by Hodogaya Chemical Co., Ltd.), and polycaprolactone polyols include Praxel 305 and Praxel 308 (both manufactured by Daicel Chemical Industries, Ltd.).

The number average molecular weight of the polyether polyol or polyester polyol used in the present invention is 300.
~ 8000. 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. In other words, water vapor can easily penetrate into the coating,
The curing reaction proceeds quickly, and carbon dioxide generated during the crosslinking reaction easily escapes outside the film. Molecular weight 300
If it is less than 1, the crosslinking density becomes too large, impeding the penetration of water vapor into the inside of the coating film and the escape of carbon dioxide outside the film, so that the curing reaction inside the coating film becomes slow and the carbon dioxide inside the coating film becomes It is not appropriate because air bubbles are easily generated.
If it exceeds 8,000, the crosslinking density becomes too low and the coating film becomes brittle, which is not suitable.

The strength of the coating film can be adjusted by appropriately selecting the molecular weight of the polyol. That is, when a low molecular weight polyol having a molecular weight of 1,000 or less is used, a hard and tough coating film can be obtained, and a molecular weight of 40
When a polyol having a molecular weight of 00 or more is used, a soft and flexible coating film can be obtained. Therefore, the mechanical properties of the coating film can be controlled by appropriately selecting and blending these polyols.

The aliphatic or alicyclic diisocyanate used in the present invention includes, for example, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, lysine diisocyanate, isophorone diisocyanate, hydrogenated xylene diisocyanate,
1,4-diisocyanatocyclohexane and the like. Hexamethylene diisocyanate is most suitable in consideration of industrial availability, weather resistance, and the speed of the curing reaction.

The polyisocyanate having an aliphatic and / or alicyclic diisocyanate as a basic skeleton in the present invention has a structure such as buret, isocyanurate, urethane, uretdione, allophanate in a molecule. The excess amount of the aliphatic and / or alicyclic diisocyanate or the polyisocyanate having them as a basic skeleton referred to in the present invention indicates that the equivalent ratio of the isocyanate group to the hydroxyl group of the polyol is 1 or more. . Therefore, when a polyol is reacted with an aliphatic and / or alicyclic diisocyanate or a polyisocyanate having these as a basic skeleton, an isocyanate group remains at a molecular terminal.

The isocyanate group content is suitably from 2 to 20% by weight. If it is less than 2% by weight, the crosslink density becomes low and the film becomes brittle. If it exceeds 20% by weight, the crosslink density becomes large and water vapor penetrates into the film and carbon dioxide escapes out of the film. And the curing reaction inside the coating film slows down, and carbon dioxide bubbles tend to be easily generated inside the coating film. The desired isocyanate group content can be attained by adjusting the amounts of the aliphatic and / or alicyclic diisocyanate or the polyisocyanate and polyol having these as a basic skeleton.

The reaction referred to in the present invention means a urethanization reaction or an allophanation reaction between the above-mentioned polyether polyol and / or polyester polyol and an aliphatic and / or alicyclic polyisocyanate, or a polyisocyanate having these as a basic skeleton. To do. The moisture hardening accelerating catalyst used in the present invention is a catalyst that promotes a reaction for generating a urea group from two isocyanate groups and one water molecule. As such a catalyst, for example, tin compounds such as dimethyltin dichloride, dibutyltin dichloride, dioctyltin dichloride, monobutyltin trichloride, dibutyltin diacetate, dibutyltin dilaurate, dibutyltin malate, dibutyltin oxide, dioctyltin oxide, and the like, tributylamine, Tertiary amines such as tetramethylethylenediamine, tetramethylpropanediamine, tetramethylhexanediamine, methylmorpholine, dimethylpiperazine, and trimethylaminomethylethanolamine.

The mixing amount of the moisture curing accelerator used in the present invention is 0.0
It is 0.5 to 2% by weight. If the amount is less than 0.005% by weight, the effect of promoting moisture hardening is not sufficient, so that it is not suitable.
If it exceeds 2% 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 polyisocyanate composition of the present invention can be used by mixing an organic solvent.
It is necessary that the organic solvent to be mixed does not have a functional group that reacts with the isocyanate group. Examples of such organic solvents include, for example, ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate, isobutyl acetate, pentyl acetate, methoxypropyl acetate, 3-methoxybutyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, acetic acid Ester compounds such as cyclohexyl, methyl propionate, butyl propionate, butyl butyrate, dioctyl adipate, and diisopropyl glutarate; ether compounds such as diisopropyl ether, dibutyl ether, dioxane, and diethoxyethane; 2-pentanone and 3-pentanone , 2-hexanone, methyl isobutyl ketone 2-heptanone, 4-heptanone, diisobutyl ketone, isophorone, cyclohexanone, ketone compounds such as methylcyclohexanone,
Aromatic compounds such as benzene, toluene, xylene, ethylbenzene, butylbenzene, and p-cymene; compounds based on polyethylene glycol dialkyl ethers such as diethylene glycol dimethyl ether, diethylene glycol diethyl ether and triethylene glycol dimethyl ether; and polyethylene glycols such as diethylene glycol diacetate Examples include dicarboxylate-based compounds.

Since the polyisocyanate composition of the present invention uses aliphatic and alicyclic diisocyanates as raw materials as described above, the polyisocyanate composition has better weather resistance and coating properties than polyisocyanate compositions using aromatic diisocyanates as raw materials. Yellowing is remarkably excellent. It also has a feature that the pot life is longer than that of a polyisocyanate composition using an aromatic diisocyanate as a raw material.

Further, the polyisocyanate composition of the present invention also has a feature that the curing reaction proceeds rapidly to the inside of the coating film. This has been achieved because the polyisocyanate composition has a structure that allows water vapor to easily penetrate, and further contains a moisture-curing accelerating catalyst. In the polyisocyanate composition of the present invention, depending on the purpose and application, pigments, leveling agents, antioxidants, ultraviolet absorbers, light stabilizers, plasticizers, used in the technical field such as a surfactant. It is also possible to mix various additives.

The one-pack moisture-curable polyisocyanate composition of the present invention is characterized by having excellent weather resistance, a long pot life, and a rapid progress of the curing reaction. In addition, because it has excellent adhesion to substrates such as metals, glass, plastics, fibers, and wood, paints, sealing materials, waterproof materials, adhesives, especially metals and metals, glass and metals, metals and plastics, Glass-to-glass, plastic-to-glass, wood-to-glass, metal-to-fiber, glass-to-fiber, plastic-to-fiber adhesives, and more specifically, adhesives for mirror backing, inks, coatings, especially paper It can be used in a wide range of fields, such as cloth, wood coating materials, casting materials, elastomers, and plastic raw materials.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described specifically with reference to examples. The measurement method used in the present invention is described below.
Isocyanate group content (hereinafter referred to as NCO content)
Was determined by back titration with hydrochloric acid after neutralizing the isocyanate group with an excess of amine.

The viscosity was measured at 25 ° C. and 60 rpm using a digital viscometer (DVM-B, Tokyo Keiki Co., Ltd.). The number average molecular weight was determined using gel permeation chromatography (GPC). GPC is
When the number average molecular weight is less than 2,000, "Column: Tosoh Corporation G1000HXL, G2000HXL, G300
0HXL, carrier: THF, detection method: parallax refractometer, data processor: Tosoh Corporation CP-8000 "
When the number average molecular weight is 2,000 or more, "Column: Tosoh G
2000HXL, G4000HXL, G5000HX
L, carrier: THF, inspection method: parallax refractometer, data processor: Tosoh Corporation Chromatocoder2
1 ".

The tack 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 reaction rate of the isocyanate group of the coating film was determined by measuring the reduction rate of the isocyanate group using FT-IR (FT / IR-700, manufactured by JASCO Corporation). The yellow value of the coating film was determined by measuring the Y value of the coating film using a color difference gloss type (LSM-5 by SM Color Computer, Suga Test Instruments Co., Ltd.).

[0023]

Example 1 A four-necked flask equipped with a stirrer, a thermometer, and a cooling tube was charged with hexamethylene diisocyanate (hereinafter, referred to as a hexamethylene diisocyanate).
600 g of HDI) and 30 of Praxel 303 (manufactured by Daicel Chemical Industries, Ltd., number average molecular weight: 550).
g, and a urethanization reaction was performed at 90 ° C. for 2 hours with stirring. At 60 ° 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 to stop the reaction.

Using a falling thin film distillation apparatus, the first time
3 Tor. (150 ° C.), 0.2 Tor. (15
(0 ° C.) to remove unreacted HDI. The polyisocyanate prepolymer was a transparent liquid, and had a yield of 54%, a viscosity of 9600 mPa · s, and an NCO content of 19.2%. The obtained polyisocyanate prepolymer was adjusted to a solid content of 80% with xylene, and 0.3 wt% of dibutyltin dilaurate was mixed with the polyisocyanate prepolymer to obtain a polyisocyanate composition.

The polyisocyanate composition obtained above was applied on a glass plate to a thickness of 100 μm,
Leave at 65% RH. No air bubbles or the like were observed in this coating film. Tack free of the coating film was 6 hours.
When the isocyanate group reaction rate of the coating film was measured,
0% and 95% on day 7. Further, the polyisocyanate composition applied on the white plate was cured at 20 ° C. and 65% RH for 1 hour.
After standing for a week, an accelerated weathering test was performed with a sunshine weather meter, and the increase in the yellow value was 2.0 at 1000 hours.

[0026]

[Embodiment 2] In the same apparatus as in Embodiment 1, HDI was
g, isophorone diisocyanate 100 g, PTG20
00 (manufactured by Hodogaya Chemical Co., Ltd., number average molecular weight: 200)
0) was charged, and a urethanization reaction was performed at 90 ° C. for 2 hours with stirring. 5.8 g of water was added, and a buret-forming reaction was performed at 160 ° C. for 1 hour.

Next, purification was carried out in the same manner as in Example 1.
The polyisocyanate prepolymer is a transparent liquid,
The yield was 38%, the viscosity was 2200 mPa · s, and the NCO content was 8.3%. Dibutyltin dichloride was mixed with the obtained polyisocyanate prepolymer at 0.02% by weight based on the polyisocyanate prepolymer to obtain a polyisocyanate composition.

The polyisocyanate composition obtained above was applied on a glass plate to a thickness of 100 μm,
Leave at 65% RH. No air bubbles or the like were observed in this coating film. The tack free of the coating was 24 hours. The isocyanate group reaction rate of the coating film was 80% on the first day and 100% on the seventh day. Further, the polyisocyanate composition applied on a white plate was subjected to 20 ° C. and 65% RH.
After one week, accelerated weathering test was conducted with a sunshine weather meter.
It was 2.8 at 0 hours.

[0029]

Example 3 In the same apparatus as in Example 1, 500 HDI was added.
g and 2-ethylhexanol (50 g), and stirred.
The urethanization reaction was performed at 0 ° C. for 2 hours. At 90 ° C., 0.02 g of tetramethylammonium capryate was added as an isocyanuration catalyst. After 4 hours, when the increase in the refractive index of the reaction solution reached 0.015, 0.1 g of phosphoric acid was added to stop the reaction.

Then, purification was carried out in the same manner as in Example 1.
Exenol 8 was added to 236 g of the obtained polyisocyanate.
47 g of 40 was added, and urethanization was performed at 120 ° C. for 4 hours. The polyisocyanate prepolymer has a viscosity of 1100
mPa · s, NCO content 14.3%.

Dibutyltin dilaurate was mixed with the obtained polyisocyanate prepolymer in an amount of 0.1% by weight based on the polyisocyanate prepolymer to obtain a polyisocyanate composition. The polyisocyanate composition obtained above was applied on a glass plate to a thickness of 100 μm and left at 20 ° C. and 65% RH. No air bubbles or the like were observed in this coating film. The tack free of the coating was 12 hours. The isocyanate group reaction rate of the coating film was 60% on the first day and 100% on the seventh day. Further, the polyisocyanate composition applied on a white plate was heated at 20 ° C.
After standing at 5% RH for 1 week, an accelerated weather resistance test was performed using a sunshine weather meter. As a result, the increase in yellow value was 1.5 at 1000 hours.

[0032]

Comparative Example 1 In the same apparatus as in Example 1, 500 g of tolylene diisocyanate and 500 g of PTG2000 (manufactured by Hodogaya Chemical Co., Ltd., number average molecular weight: 2000) were charged, and a urethanization reaction was carried out at 90 ° C. for 2 hours with stirring. went. 6
At 0 ° 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 to stop the reaction.

Then, purification was carried out in the same manner as in Example 1. The polyisocyanate prepolymer was a transparent liquid, and had a yield of 54%, a viscosity of 100000 mPa · s or more, and an NCO content of 8.2%. The obtained polyisocyanate prepolymer was adjusted to a solid content of 50% with xylene, and dibutyltin dilaurate was mixed at 0.3% by weight with respect to the polyisocyanate prepolymer to obtain a polyisocyanate composition.

The polyisocyanate composition obtained above was applied on a glass plate to a thickness of 100 μm,
Leave at 65% RH. No bubbles or the like were observed in this coating film. The tack free of the coating was 8 hours. When the isocyanate group reaction rate of the coating film was measured,
%, And 100% on the seventh day. After the polyisocyanate composition applied on the white plate was allowed to stand at 20 ° C. and 65% RH for 1 week, an accelerated weather resistance test was performed with a sunshine weather meter. As a result, the increase in yellow value was 24 in 1000 hours.

[0035]

The one-part moisture-curable polyisocyanate composition of the present invention has excellent weather resistance, a long pot life, and a rapid progress of the curing reaction. 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.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical indication location C09K 3/10 C09K 3/10 D

Claims (1)

[Claims] 1. A polyisocyanate obtained by reacting a polyether polyol and / or polyester polyol having a number average molecular weight of 300 to 8000 with an excess amount of an aliphatic and / or alicyclic diisocyanate or a polyisocyanate having them as a basic skeleton. A prepolymer and 0.0 to the polyisocyanate prepolymer.
A one-part moisture-curable polyisocyanate composition comprising a mixture of 0.5 to 2% by weight of a moisture-curing acceleration catalyst.