JP3637560B2 - Moisture curable urethane composition - Google Patents

Description

【００３７】
【表２】

【００３８】
比較例１はブチレンエーテル結合を含有しないウレタンプレポリマーを用いているため耐水後の吸水率が高く、耐水後の強度が低くなり、特に耐水性を要する用途には適用できないものであった。また、オキサゾリジン化合物を用いない比較例２は耐水性に問題はないものの発泡し、強度が低く硬化も遅い結果となった。
【００３９】
【発明の効果】
本発明の組成物は、硬化時に炭酸ガスによる発泡がなく、硬化性に優れ、更に耐水性にも優れ、特にコーティング材、シーリング材、接着剤に有用である。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a moisture curable urethane composition that is free from foaming by carbon dioxide gas during curing, has excellent curability, and has excellent water resistance, and is particularly useful for coating materials, sealing materials, and adhesives.
[0002]
[Prior art]
JP-A-57-94056 is known as a conventional moisture-curable urethane composition, but the coating film often swells due to carbon dioxide generated when moisture and isocyanate groups react during curing. There are problems that occur. Moisture dissociation type crosslinking agents such as ketimine and enamine have been proposed in order to suppress the generation of carbon dioxide which causes blistering. Among them, JP-A-6-293821, JP-A-7-33852, JP-A-Hei. A composition using an oxazolidine compound proposed in Japanese Patent Application Laid-Open No. 7-10949 is a material that does not generate carbon dioxide and has a relatively balanced performance.
[0003]
However, a coating film cured by reacting with a urethane prepolymer is exposed to high-temperature water for a long period of time when an oxazolidine group as shown in JP-A-6-293821, etc. is ring-opened by moisture to generate active hydrogen. In this case, there is a problem that the mechanical strength of the coating film is reduced due to water absorption when used under severe conditions. Such a phenomenon is considered to be due to the high hydrophilicity of the amine salt of the acid used as the dissociation catalyst of the secondary amine and the oxazolidine due to the primary hydroxyl group generated by dissociation of oxazolidine due to moisture or the opened oxazolidine ring.
[0004]
[Problems to be solved by the invention]
The present invention relates to a moisture curable urethane using oxazolidine, and provides a moisture curable urethane composition that is free from foaming by carbon dioxide gas during curing, has excellent curability and water resistance, and is useful for coating materials and sealing materials. Is.
[0005]
[Means for Solving the Problems]
The present inventors have conducted extensive studies results, the (A) comprises a polyisocyanate and a polyoxyalkylene polyol at the end obtained by reacting two or more isocyanate groups, and butylene ether bond in the polyoxyalkylene polyol 5 Urethane prepolymers using up to 80 wt%, ethylene ether linkages 0-10 wt% and propylene ether linkages 10-95 wt%, (B) (b1) polyisocyanate and (b2) N-2-hydroxyalkyl It has been found that a moisture-curable urethane composition characterized by containing an oxazolidine-containing urethane compound having at least one oxazolidine group at a terminal obtained by reacting with oxazolidine solves the aforementioned problems. The present invention is further described below.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
A terminal isocyanate group obtained by reacting a polyisocyanate with a polyoxyalkylene polyol used in the present invention has 2 or more, and the polyoxyalkylene polyol 5-80% by weight of butylene ether bond in the ethylene ether A urethane prepolymer (hereinafter referred to as BO-containing urethane prepolymer) (A) containing 0 to 10% by weight of a bond and 10 to 95 % by weight of a propylene ether bond is 5 to 80 % by weight of a polyisocyanate and a butylene ether bond. %, A polyoxyalkylene polyol containing 0 to 10% by weight of an ethylene ether bond and 10 to 95 % by weight of a propylene ether bond, and a urethane prepolymer prepared by an ordinary method under an excess of polyisocyanate.
[0007]
The urethane prepolymer (b1) having two or more isocyanate groups at the terminal is a urethane prepolymer prepared by a conventional method using polyisocyanate and polyol, for example, polyoxyalkylene polyol in excess of polyisocyanate. .
[0008]
Such polyoxyalkylene polyol is obtained by adding ethylene oxide, propylene oxide, butylene oxide alone or in combination of two or more thereof to ethylene glycol, propylene glycol, water, glycerin, trimethylolpropane (TMP), pentaerythritol and the like by a known method. It is a polyol obtained in this way.
[0009]
Examples of the polyisocyanate used in the present invention include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, diphenylmethane diisocyanate, partially carbodiimidized diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate, and tolylene diisocyanate. , Aromatic diisocyanates such as naphthalene diisocyanate, phenylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, hydrogenated diphenylmethane diisocyanate, cyclohexane diisocyanate, aliphatic diisocyanate, alicyclic diisocyanate The above mixture is mentioned.
[0010]
The polyoxyalkylene polyol which is a constituent component of the BO-containing urethane prepolymer (A) preferably has a number average molecular weight of 500 to 16000. The prepolymer (A) contains 5 to 80% by weight , preferably 10 to 70% by weight , of a butylene ether bond as a polyoxyalkylene polyol. With such a content of butylene ether bonds, the water absorption is excellent and the physical properties after the water resistance test are excellent. In particular, the polyoxyalkylene polyol component of the urethane prepolymer (A) is in the range of 5 to 80% by weight of butylene ether bonds, 0 to 10% by weight of ethylene ether bonds and 10 to 95% by weight of propylene ether bonds.
[0011]
The number of terminal isocyanate groups in the BO-containing urethane prepolymer (A) is preferably 2 or more, more preferably 2 to 3. Furthermore, the NCO / OH ratio of isocyanate and polyol is preferably 1.4 or more, more preferably 1.4 to 5.0. The residual NCO% is preferably 1 to 20% by weight.
[0012]
On the other hand, the oxazolidine-containing urethane compound (B) is a urethane prepolymer (b1) containing two or more isocyanate groups at the terminal obtained by reacting polyisocyanate or polyisocyanate with polyoxyalkylene polyol, and N-2-hydroxyalkyl. It has at least one oxazolidine group at the terminal obtained by reacting with oxazolidine (b2).
[0013]
The polyoxyalkylene polyol of such a urethane prepolymer preferably has an oxyethylene chain. However, even a polyol in which a polyol having no oxyethylene chain and a polyol having an oxyethylene chain are mixed can be used as the component (b1). The average content of oxyethylene chains in the oxyalkylene chain is preferably 1 to 30% by weight. When the content of the oxyethylene chain is in the above range, the curing rate is high, and the curability and water resistance are excellent. However, the oxyethylene chain amount of the (A) component and the (B) component is calculated and totaled, and the content of the oxyethylene chain is less than 10% by weight with respect to the total amount of the (A) component and the (B) component. It is preferable that If it is this range, it will become preferable water resistance.
[0014]
The urethane prepolymer (b1) preferably has a number average molecular weight of 500 to 8000. When the molecular weight is 500 to 8000, the base followability and the curing speed are excellent. Further, the average number of NCO groups at the end of the urethane prepolymer (b1) is preferably 2.0 to 2.6, and when the number of NCO groups is such, better results are obtained with better curability and foundation followability. Furthermore, the NCO / OH ratio of isocyanate and polyol is preferably 1.6 or more, more preferably 1.8 to 4.0. The residual NCO% is preferably 1 to 15% by weight.
[0015]
The reaction ratio between the urethane prepolymer (b1) and the N-2-hydroxyalkyloxazolidine (b2) is preferably NCO / 0H = 0.95 to 3.0. If NCO / 0H is within the range, unreacted N-2-hydroxyalkyloxazolidine is less likely to remain, gives good results in storage stability, and easily suppresses a decrease in curing speed and an increase in viscosity. It is.
[0016]
The N-2-hydroxyalkyloxazolidine (b2) used for the synthesis of the oxazolidine-containing urethane compound (B) includes aldehydes such as formaldehyde, acetaldehyde, propylaldehyde, butyraldehyde, benzaldehyde, and diethanolamine, dipropanolamine, etc. It is a compound obtained by a well-known condensation reaction with dihydroxyalkylamines.
[0017]
The number of terminal oxazolidine groups in the oxazolidine-containing urethane compound (B) is preferably 1 to 3. Within this range, the extensibility after curing becomes high, which is preferable. Needless to say, if the urethane oxazolidine prepolymer (B) has at least one oxazolidine group at the terminal, the other terminal may be an isocyanate group.
[0018]
The ratio of the BO component-containing prepolymer (A) to the oxazolidine-containing urethane compound (B) is the ratio between the NCO group of the prepolymer (A) and the active hydrogen group generated by ring opening of the oxazolidine-containing urethane compound (B) with water. The ratio is preferably in the range of 0.4 to 4.0. If it is this range, generation | occurrence | production of a carbon dioxide gas is low, the swelling of a coating film can be suppressed, and it is excellent in storage stability. Considering such points, the mixing ratio of (A) and (B) is preferably in the range of 60: 1 to 1:30 by weight.
[0019]
When used in these applications, the composition of the present invention is an acid, an organic solvent, an inorganic filler, a process oil, a plasticizer, a thixotropic agent, an extender pigment, an weather resistant pigment, and a dissociation catalyst for oxazolidine. It may contain various additives such as an ultraviolet inhibitor and a stabilizer for maintenance and improvement. These mixtures can be produced with a mixing and kneading apparatus sufficient to be able to uniformly mix and ensure storage stability.
[0020]
As the acid as the dissociation catalyst, for example, known acids such as salicylic acid, orthophthalic acid, terephthalic acid, trimellitic acid, pyromellitic acid, mellitic acid and acid anhydrides thereof are used, and terephthalic acid and salicylic acid are particularly preferable. It is done.
[0021]
As the solvents, usual urethane solvents such as toluene, xylene, terpene, and ethyl acetate can be used.
[0022]
Examples of the thixotropic agent include surface-treated calcium carbonate, polyvinyl chloride powder, fine powder silica, bentonite and the like. In addition, the composition of the present invention may be mixed with a petroleum-based high-boiling aromatic fraction, petroleum resin, or the like.
[0023]
Examples of the plasticizer include ester plasticizers such as dibutyl phthalate, dioctyl phthalate, diundecyl phthalate, dilauryl phthalate, butyl benzyl phthalate, diisodecyl phthalate, dibutyl adipate, dioctyl adipate, diisononyl adipate, dioctyl azelate, and dioctyl sebacate. Examples thereof include phosphate plasticizers such as trioctyl phosphate and triphenyl phosphate.
[0024]
Examples of the stabilizer include an antioxidant and an ultraviolet absorber. Examples of the inorganic filler include powders of inorganic compounds such as calcium carbonate, calcium oxide, clay, talc, titanium oxide, aluminum sulfate, kaolin, clay, and glass balloon. The addition amount is preferably 5 to 70, more preferably 10 to 60% by weight in the composition.
[0025]
The composition of this invention can be used for a coating material, a sealing material, and an adhesive agent as a typical use. As a coating material, it can be used for paint, building roof waterproofing materials, parking lot waterproofing materials, wall materials, flooring materials, stadium surface paving materials, and the like. Moreover, as a sealing material, it can utilize for the sealing material for construction for civil engineering, such as concrete, a sizing board, and a metal. In addition, adhesives for building interior materials such as plastic flooring, adhesives for rooftop waterproof sheets, adhesives for tiles and sheets, such as adhesives for natural stone, ceramic, rubber, wood, etc., and fibrous materials Can be used as a binder.
[0026]
【Example】
EXAMPLES Next, although an Example and a comparative example demonstrate this invention in detail, this invention is not limited to these Examples. In the following, all parts and percentages are based on weight unless otherwise specified.
[0027]
<Synthesis of component (A)>
(Production Example 1 of BO-containing urethane prepolymer)
700 g (0.35 mol) of polybutylene ether diol having a number average molecular weight of 2000, 300 g (0.1 mol) of polypropylene ether triol having a number average molecular weight of 3000, 191.4 g (1.1 mol) of 2,4-tolylene diisocyanate, That is, the reaction was carried out with stirring in a flask at 80 ° C. for 15 hours under a nitrogen stream at an NCO / OH equivalent ratio of 2.2 to obtain a BO-containing urethane prepolymer (A-1) having an NCO% of 4.25%. It was.
[0028]
(Production Example 2 of BO-containing urethane prepolymer)
In Production Example 1 of BO-containing urethane prepolymer, instead of 300 g (0.1 mol) of polypropylene ether triol having a number average molecular weight of 3000, 300 g of polyethylene propylene ether triol having a number average molecular weight of 3000 and an oxyethylene chain content of 8% (0. 1 mol) was used in the same manner as described above to obtain a BO-containing urethane prepolymer (A-2) having an NCO% of 4.22%.
[0029]
(Production Example 3 of BO-containing urethane prepolymer)
Was synthesized in the same manner except for using polypropylene ether di-ol with a number average molecular weight of 2000 instead of polybutylene ether diol having a number average molecular weight of 2000 in Preparation Example 1 of BO-containing urethane prepolymer, NCO% is 4.23 % Urethane prepolymer (A-3) was obtained.
[0030]
<Synthesis of component (B)>
(Production Example 1 of Oxazolidine-Containing Urethane Compound)
A mixture of 500 g (0.104 mol) of polyethylene propylene ether triol having a number average molecular weight of 4800 and an oxyethylene chain content of 15% and 500 g (0.25 mol) of polypropylene ether diol having a number average molecular weight of 2000 are mixed. A polyol having a content of 7.5%, an average functional group number of 2.29, and a number average molecular weight of 2820 was obtained. Further, 143.3 g (0.853 mol) of hexamethylene diisocyanate, that is, an NCO / OH equivalent ratio of 2.1, was allowed to react with stirring in a flask at 80 ° C. for 48 hours under a nitrogen stream, and the NCO% was 3.29%. % Urethane prepolymer (b1-1) having 2.29 terminal NCO groups per molecule.
[0031]
140.8 g of urethane prepolymer (b1-1) and 15.9 g of 2-isopropyl 3 (2hydroxyethyl) 1,3 oxazolidine, that is, an NCO / OH equivalent ratio of 1.1, at 60 ° C. for 48 hours under a nitrogen stream The reaction was conducted while stirring in a flask to obtain an oxazolidine-containing urethane compound (OXZ-1). As a result of measuring GPC of this composition, it was confirmed that the content of the remaining 2-isopropyl 3 (2hydroxyethyl) 1,3 oxazolidine was 1% or less.
[0032]
(Production Example 2 of Oxazolidine-Containing Urethane Compound)
20 g (0.033 mol) of polyethylene propylene ether triol having a number average molecular weight of 600 and an oxyethylene chain content of 30% and 270 g (0.45 mol) of polypropylene ether diol having a number average molecular weight of 600 are mixed to obtain an average of oxyethylene chains. A polyol having a content of 2.1%, an average functional group number of 2.07, and a number average molecular weight of 600 was obtained. Further, 174 g (1.0 mol) of 2,4tolylene diisocyanate, that is, an NCO / OH equivalent ratio of 2.0, was allowed to react in a flask at 60 ° C. for 48 hours with stirring in a nitrogen stream for 48 hours, resulting in an NCO% of 9. A urethane prepolymer (b1-2) having 07% and a terminal NCO group number of 2.07 per molecule was obtained.
[0033]
Urethane prepolymer (b1-2)) 48.7 g and 2-isopropyl 3 (2 hydroxyethyl) 1,3 oxazolidine 15.9 g, that is, an NCO / OH equivalent ratio of 1.05 at 60 ° C. under a nitrogen stream. The reaction was carried out with stirring in the flask for 48 hours to obtain an oxazolidine-containing urethane compound (OXZ-2). As a result of measuring GPC of this composition, it was confirmed that the content of the remaining 2-isopropyl 3 (2hydroxyethyl) 1,3 oxazolidine was 1% or less.
[0034]
(Examples 1-2, Comparative Examples 1-2)
<Combination of compound>
Next, it was dried under reduced pressure at 120 ° C. for 5 hours in a closed-type planetary mixer, and 320 parts of calcium carbonate (NS-200 manufactured by Nitto Flour Chemical Co., Ltd.) adjusted to a moisture content of 0.05% or less, and dried under reduced pressure at 120 ° C. for 5 hours. , 30 parts of fatty acid-treated calcium carbonate (Hakuenka CCR made of Shiroishi calcium) adjusted to a water content of 0.1% or less, 80 parts of xylene, 90 parts of dioctyl phthalate (hereinafter abbreviated as DOP), terephthalic acid and DOP by weight ratio 1: After adding a predetermined amount of 10 parts of paste preliminarily mixed in 1 using a roll mixer, 0.6 part of salicylic acid, urethane prepolymer (A) and oxazolidine-containing urethane compound (B) shown in the table below, 60 parts Deaeration was performed under a reduced pressure of Toll to obtain a moisture-curable urethane compound. Further, as comparative examples, those using urethane prepolymer (A-3) and oxazolidine-containing urethane compound (B) (Comparative Example 1) and those not using oxazolidine-containing urethane compound (B) in Examples (Comparison) Example 2) was also carried out.
[0035]
[Test method]
(Curing test)
Curing is done by flowing a sample at a rate of 1.5 mm on a glass plate (30 * 30 cm) that is surrounded on all sides by a frame and affixed with release paper, left at 25 ° C x 50%, and then touched with a finger. The time until film movement disappeared was measured.
(Non-foaming test)
For non-foaming properties, a sample was poured at a rate of 2 mm on a slate plate (30 × 30 cm) surrounded by a frame on all sides, and cured under conditions of 50 ° C. × 90%. The presence or absence of holes was observed. Those with no blisters and pinholes were marked with ◯, and those with blisters and pinholes were marked with ×.
(Tensile property test)
Tensile properties were measured by flowing a sample at a rate of 1.5 mm on a glass plate (30 × 30 cm) surrounded by a frame on all sides and affixed with release paper, and allowed to cure for 14 days under conditions of 25 ° C. × 50%. Thereafter, the tensile strength (kg / cm ² ) and elongation at break (%) were measured using a tensile tester under conditions of a tensile speed of 500 mm / min.
(Water resistance test)
A dumbbell No. 3 type test piece prepared according to the normal tensile physical property test method is dipped for 30 days at 60 ° C. and then immediately taken out to measure the weight, and the weight change rate (%) compared to before dipping is measured. Further, after standing for 4 hours at 25 ° C. × 50%, tensile strength (kg / cm ² ) and elongation at break (%) were measured according to the normal tensile physical property test method.
[0036]
[Table 1]

[0037]
[Table 2]

[0038]
Since the comparative example 1 uses the urethane prepolymer which does not contain a butylene ether bond, the water absorption after water resistance is high, the strength after water resistance is low, and it cannot be applied to applications requiring water resistance in particular. In Comparative Example 2 in which no oxazolidine compound was used, although there was no problem with water resistance, foaming occurred and the strength was low and the curing was slow.
[0039]
【The invention's effect】
The composition of the present invention is free from foaming due to carbon dioxide gas at the time of curing, has excellent curability, and also has excellent water resistance, and is particularly useful for coating materials, sealing materials and adhesives.

Claims (1)

(A) a polyisocyanate and a polyoxyalkylene polyol terminal isocyanate group obtained by reacting a a a 2 or more, and the polyoxyalkylene polyol is butylene ether bond 5-80 wt%, ethylene ether bond 0 Urethane prepolymer using 10% by weight and 10% to 95 % by weight of propylene ether bond , (B) (b1) Two isocyanate groups at the terminal obtained by reacting polyisocyanate or polyisocyanate with polyoxyalkylene polyol Moisture curing characterized by containing an oxazolidine-containing urethane compound having at least one oxazolidine group at the terminal obtained by reacting the urethane prepolymer containing (b2) with N-2-hydroxyalkyloxazolidine Urethane composition.