JP2002212541A - Two component system polyurethane sealing material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a two-component system polyurethane sealing material that facilitates the mixing work on mixing operation in no need of plasticizer for softening with reduced occurrence of bubbles after curing and reduced staining on the coated surfaces and gives low modulus and high elongation and excellent cold curing behavior. SOLUTION: The objective two component system polyurethane sealing material comprises (A) the base material of an isocyanate-terminated urethane prepolymer prepared by allowing the isocyanate (NCO) in the polyisocyanate to react with the hydroxyls in the mixed polyols of polyoxypropylene diol and polyoxypropylene triol at a weight ratio of (3-7)/(7-3) in the range of molar ratio (NCO/OH) of 1.60-2.00 and (B) a curing agent including a polyol component of polyoxypropylene diol and polyoxypropylene triol at a weight ratio of (0-3)/(10-7) or mixed polyol components.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention provides mixing easiness at the time of a mixing operation, reduces foaming after curing,
In addition, the present invention relates to a two-component polyurethane sealing material which imparts low modulus, high elongation properties, and is excellent in low-temperature curability, when the surface is subjected to finish coating with less paint contamination. The present invention is suitable as a two-component polyurethane sealing material containing no plasticizer.

[0002]

2. Description of the Related Art A two-component polyurethane sealing material is widely used as a sealing material for achieving watertightness and airtightness in civil engineering and construction works. The two-component polyurethane-based sealing material comprises (A) a base comprising an isocyanate group-terminated liquid polymer (prepolymer) obtained by allowing an excess of diisocyanate to act on a polyol represented by a polyoxypropylene polyol; Polyurethane components, such as polyoxypropylene polyols, which react with water and urethane are used as a curing agent containing a plasticizer, a viscosity adjusting diluent, a curing accelerator, an inorganic filler, a viscosity improver, a coloring agent, an antioxidant, etc. This is a two-liquid mixed type sealing material that is cured by reaction. When considering the reaction mechanism of the backbone polymer of the two-component polyurethane sealing material, the compounding ratio is (A)
An isocyanate group of a prepolymer component in the base;
It is common knowledge that the molar ratio of the hydroxyl group of the polyol component in the (B) curing agent (hereinafter referred to as NCO / OH ratio) is 1 or more. The reason for this is that if it is less than 1, unreacted hydroxyl groups will remain in excess and cause poor curing under the influence of hydroxyl groups. Therefore, an overseas publication (“Se”) which is a bible of two-component polyurethane-based sealing materials
"alants" EDITED BY Adolfas Damus
is REINHOLD PUBLISHING CO
RPORATIONP. 160), the NCO /
The OH ratio is indicated as 1.05 to 1.25, and is described in a domestic document (“Synthesis / Blending and Functionalization / Application Development of Latest Polyurethane”, Technical Information Association, Ltd., July 15, 1989)
P. 408) describes 1.05 to 1.20, and it is common technical knowledge that at least the NCO / OH ratio is 1 or more.

[0003] However, conventional products having this range set have a high viscosity after mixing, a high modulus after curing, and a high modulus.
Since only low elongation properties can be obtained, plasticizers such as dioctyl phthalate (DOP) and dioctyl adipate (DOA), which are softeners, are always blended in order to improve low modulus and high elongation. This plasticizer is an indispensable means in the prior art for obtaining physical properties such as low modulus and high elongation. Further, in the prior art, the plasticizer also has a role of a diluent in order to facilitate mixing because of high viscosity. However, when this plasticizer is blended, the surface tackiness after curing is strong due to softening by an external additive, which gives a disadvantage that soot, dust and the like are attached.
In addition, when curing at a low temperature, the plasticizer may act as a binder and the curing may be delayed.

Further, in the industry, the surface of a polyurethane-based sealing material is routinely coated. However, since the plasticizer in the sealing material leaches (bleeds) with time, discoloration, darkening, It has been a long time since the solution of this problem has been awaited, but it has not been solved yet. in addition,
It is pointed out that phthalate plasticizers represented by dioctyl phthalate (DOP) can be environmental hormones. Thus, the blending of the plasticizer is a two-component polyurethane-based sealing having desirable physical properties that does not contain a plasticizer (hereinafter referred to as a plasticizer-free type), despite the fact that it is a bitter measure in the prior art today. There is no technology to provide the material.

Recently, a plasticizer-free type two-component polyurethane-based sealing material has been disclosed in Japanese Patent Application Laid-Open No. 2000-1.
No. 44098, this technology has a design area that deviates from the common general technical knowledge, that is, an NCO / OH ratio.
It is an essential requirement to be 0.5 to 1.0 which is 1 or less. Therefore, it is inevitable that the hydroxyl groups are excessive and the hydroxyl groups remain essentially, and the insufficient curing due to the excessive hydroxyl groups and the adhesion of the stain due to the increase of the surface tack have not been eliminated. Thus, the compounding region in which isocyanate groups are preferable in terms of quality, that is, the NCO / OH ratio exceeds 1 (particularly, there is no danger of remaining hydroxyl groups), and the NCO / OH ratio, which is common technical knowledge, Is 1.0
In the range of 5 to 1.25, no two-component polyurethane-based sealing material which exhibits excellent physical properties, such as excellent mixing properties at the time of use, low modulus and high elongation, without using a plasticizer, is found at all. is the current situation.

[0006]

SUMMARY OF THE INVENTION In a two-component polyurethane sealing material, by comprehensively examining the combination of a prepolymer and a polyol, it is not necessary to soften with a plasticizer, and the hydroxyl group is essentially eliminated. In the region where there is no residue, it provides mixing easiness during the mixing operation, less foaming after curing, less contamination of the painted surface, provides physical properties such as low modulus and high elongation, and is excellent in low-temperature curability 2 It is to provide a component type polyurethane sealant.

[0007]

Means for Solving the Problems The present inventors considered why a plasticizer has been required in a two-component polyurethane sealing material. The basis of this physical property is the formation reaction of the backbone polymer at room temperature crosslinking, that is, the isocyanate group-terminated urethane prepolymer component in the base (A) and the polyol component in the curing agent (B) are complexed by the room temperature crosslinking. It is a crosslinking reaction that forms a three-dimensional structure.

(A) If the base material is a prepolymer limited to, for example, diol and diisocyanate, the molecular structure is relatively simple, but actually, the composition of the polyol itself, the average number of functional groups of the specific polyol (degree of branching), the specific For a polyol component or a mixed polyol component in which various factors such as the number average molecular weight of the polyol are combined, NCO /
By causing excess polyisocyanate to act in consideration of the OH ratio, a prepolymer having a urethane bond in the molecule and having a molecular end at an isocyanate group is formed. Therefore, the prepolymer itself has a complicated linked polymer structure. (B) The polyol component in the curing agent is a polyol component or a mixed polyol component in which the composition of the polyol itself, the average number of functional groups of the specific polyol, and the number average molecular weight of the specific polyol are combined.

If the isocyanate group (NCO) of the prepolymer in the base (A) and the hydroxyl group (OH) of the polyol component in the curing agent (B) are blended at an NCO / OH ratio of 1 or more, Consider this polymer formation process because the prepolymer and the majority of the polyol or mixed polyol components form urethane bonds and are converted to polymers, and the excess excess isocyanate groups cause cross-linking due to moisture in the air. This results in a more complex polymer structure than the prepolymer stage. From this, there should be an infinite number of combinations of the polymer structure and the obtained physical properties. The reason that the two-component polyurethane-based sealant in the conventional industry has long required a plasticizer is based on the technology of using an existing prepolymer, and without modifying or changing the prepolymer, the polyol component is not used. To the conventional design domain (ie, NCO / OH ratio =
It is presumed that the degree of freedom was lost due to the combination of 1.05 to 1.25) as a design standard.

[0010] On the other hand, the present inventors considered this technology to be an unexplored field, thought that it would be possible to solve this problem by considering the design of a prepolymer and conducting a study combining this with a polyol. That is, in the stage of designing the prepolymer component in the base material (A), the prepolymer composition, the average number of functional groups of the specific polyol, the combination of the specific polyol average molecular weight, and the NCO / OH ratio are examined in parallel with the examination of the prepolymer. With respect to the components, (B) the composition of the polyol itself in the curing agent, the average number of functional groups of the specific polyol, and the specific molecular weight of the specific polyol are blended in the conventional design range (NCO / OH ratio: 1.05 to 1.25). We thought that if we did this continuously and comprehensively, we would be able to discover unexplored fields, and we conducted research for many years according to this idea. As a result, in the conventional design area, we finally found an area that gives easy mixing with low viscosity without containing any plasticizer, and gives low modulus and high elongation properties after curing. We have completed a two-component polyurethane sealing material.

Hereinafter, specific solutions of the present invention will be described. The invention of claim 1 is characterized in that (A) the weight ratio of polyoxypropylene diol to polyoxypropylene triol is 3
The NCO / OH ratio of the polyisocyanate compound was 1.60 to 2.0 with respect to the mixed polyol having a viscosity of 7 to 7/3.
A base consisting of an isocyanate group-terminated urethane prepolymer component acted in the range of 0; and (B) a polyol component or a mixed polyol having a weight ratio of polyoxypropylene diol to polyoxypropylene triol of 0-3 / 10-7. A molar ratio (NCO / OH ratio) of the isocyanate group (NCO) of the isocyanate group-terminated urethane prepolymer in the base (A) and the hydroxyl group (OH) of the polyol in the (B) curing agent. To 1.0
The present invention relates to a two-component polyurethane sealing material characterized by reacting at 5-1.25.

In the design area of the present invention, if a curing accelerator, an inorganic filler, a viscosity improving agent, a colorant, a viscosity adjusting diluent, an antioxidant, etc. are blended without using a plasticizer, mixing can be achieved. To provide a two-component polyurethane sealing material that gives easy mixing during work, gives less foaming after curing, has less contamination of the painted surface, gives low modulus and high elongation properties, and has excellent low-temperature curability. Can be. (A) The weight ratio of polyoxypropylene diol to polyoxypropylene triol in the base is 3-7 / 7-3.
Is preferred in order to obtain easy mixing, low modulus after curing, and high elongation properties, and most preferably 4 to 6 /.
It is in the range of 6-4. When the weight ratio of the polyoxypropylene diol is less than 3, the physical properties after curing become high modulus, so that the effects of the present invention cannot be obtained. When the weight ratio exceeds 7, the poor curing occurs, so that the effects of the present invention occur. Can not be obtained.

(A) The NCO / OH ratio in the base is 1.6
It is 0 to 2.00, preferably 1.70 to 1.90. When the NCO / OH ratio in the base is less than 1.60, the viscosity of the prepolymer is high, so that the yield is likely to decrease and mixing is poor, and after curing, the coating surface is liable to be contaminated, and exceeds 2.00. And the unreacted diisocyanate increases, causing great harm to the human body and easily causing foaming,
It is difficult to obtain physical properties such as low modulus and high elongation. (B) The weight ratio of polyoxypropylene diol to polyoxypropylene triol in the curing agent is preferably from the viewpoint of obtaining higher elongation after curing as the amount of polyoxypropylene diol decreases, and the most preferable weight ratio in terms of physical properties is 0. / 10
That is, it is preferable to use only polyoxypropylene triol. On the other hand, when importance is placed on low modulus, it is preferable that 0.5 to 2 / 9.5 to 8, that is, a small amount of polyoxypropylene diol be present. Others
In consideration of dirt, foaming, and curability of the coated surface after curing, 0 to 1/10 to 9 is preferable.

(A) The isocyanate group (NCO) of the isocyanate group-terminated urethane prepolymer in the base and the (B) NCO of the hydroxyl group (OH) of the polyol in the curing agent
If the / OH ratio is less than 1.05, hydroxyl groups are likely to remain, and adhesion of dirt on the surface of the sealing material and decrease in modulus due to increase in surface tack become remarkable.
If it exceeds 5, the modulus is increased and the elongation is significantly reduced, and there is a risk of foaming. Among them, the range that gives mixing easiness at the time of mixing work and has excellent low-temperature curability because no hydroxyl groups remain after curing, less foaming, less contamination of the coating surface, low modulus, and high elongation properties Is 1.05 to 1.15.

According to a second aspect of the present invention, in the polyurethane sealing material, the polyoxypropylene diol in the base (A) has a number average molecular weight of 1,000 to 3,000, preferably 1,000 to 2,000, and a number average molecular weight of the polyoxypropylene triol. The two-component polyurethane-based sealing material composition according to claim 1, wherein the molecular weight is selected from the range of 3,000 to 5,000, preferably 3,000 to 4,000. When the number average molecular weight of the polyoxypropylene diol is less than 1,000 or the number average molecular weight of the polyoxypropylene triol is less than 3,000, the number of urethane bonds in the urethane prepolymer increases, the viscosity increases, and the workability decreases.

When the number average molecular weight of the polyoxypropylene diol is greater than 3000, or when the number average molecular weight of the polyoxypropylene triol is greater than 5000, the NCO / OH ratio of (A) base / (B) curing agent is maintained. Therefore, it is necessary to increase the NCO content, and the amount of isocyanate monomer increases, which causes problems of toxicity and foaming of free isocyanate. Further, when one or more polyoxypropylene diols and polyoxypropylene triols in the above number average molecular weight range are selected and used in the base (A), the effect of the present invention is further improved.

According to a third aspect of the present invention, in the polyurethane sealing material, the number average molecular weight of the polyoxypropylene diol in the curing agent (B) is 1,000 to 3,000,
The two-component polyurethane-based sealing according to claim 1 or 2, wherein the number average molecular weight of the polyoxypropylene triol is preferably selected from the range of 3,000 to 5,000, preferably 4,000 to 5,000. About materials. The number average molecular weight of polyoxypropylene diol is less than 1000, or the number average molecular weight of polyoxypropylene triol is 300
If it is less than 0, it is necessary to increase the NCO content of the base (A). When the number average molecular weight of the polyoxypropylene diol is larger than 3,000, or when the number average molecular weight of the polyoxypropylene triol is larger than 5,000, the viscosity is increased and the workability is reduced. When one or more polyoxypropylene triols having the number average molecular weight in the (B) curing agent are selected and used, the effect of the present invention is further improved.

According to a fourth aspect of the present invention, in the polyurethane sealing material, a 50% tensile stress of 0.05 to 0.20 N in a test shown in JIS A 1439 in a state of not containing a plasticizer as a compounding component. / Mm ² ,
4. The method according to claim 1, wherein the elongation at the maximum load is preferably 0.10 to 0.15 N / mm ² , and the elongation at the maximum load is at least 500%, preferably at least 600%. 5. The present invention relates to the two-component polyurethane-based sealing material described above. JIS A 1439 is a test method for determining the quality of a sealing material. If the 50% tensile stress is too low, the surface tack is promoted. If the tensile stress is too high, the joint follow-up performance is deteriorated and the adherend is broken. Occurs. When the elongation at the time of the maximum load is 500% or less, the joint movement followability is poor. The property range of the sealing material is such that the same low modulus and high elongation properties as those of a conventional two-component polyurethane sealing material containing a plasticizer can be realized without adding a plasticizer.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In practicing the present invention,
(A) Synthesis of a prepolymer as a base, (B) a two-component polyurethane-based sealing material obtained by a mixing and processing method of a polyol component as a curing agent, and then mixing (A) and (B) to perform sealing. The method used as a material will be described. (A) The synthesis of the base was carried out by setting the weight ratio of polyoxypropylene diol and polyoxypropylene triol to 3 to 7/7 to 3 in a urethane polymerization apparatus equipped with a stirrer, a heating device, a vacuum dehydration device, and a nitrogen gas flow device. After dehydration under reduced pressure, the atmosphere was replaced with nitrogen, and cooled to about 50 ° C. under a nitrogen stream, and the NCO / OH ratio was calculated to be 1.60 to 2.00. After adding a polyisocyanate compound such as diisocyanate or xylene diisocyanate, 8
The reaction is carried out at 0 to 100 ° C. for about 4 to 8 hours, and when the isocyanate content reaches the designed value, the reaction is cooled and, as the end point of the reaction, divided into closed containers while purging with nitrogen. In this case, a small amount of dibutyltin dilaurate (DBTDL)
May be blended.

The polyoxypropylene diol and the polyoxypropylene triol may act as a mixed polyol with the polyisocyanate or may act in a stepwise manner. In the present invention, this is referred to as a base in a two-component polyurethane sealing material.

(B) Since the polyol component in the curing agent is not affected by moisture unlike the prepolymer,
A polyol or mixed polyol is charged into a processing pot that can knead and process closed high-viscosity products, metal-based curing accelerators such as tin, lead, and bismuth, amine curing catalysts, inorganic fillers such as calcium carbonate, and anhydrous silica. , A viscosity improver such as amide wax, a coloring agent, an antioxidant, a diluent for adjusting viscosity, and a dehydrating agent such as quicklime are appropriately mixed and uniformly mixed. In the present invention, this is referred to as a curing agent in a two-component polyurethane sealing material.

In the blending of (A) and (B), the number of isocyanate groups is calculated from the isocyanate group content of the prepolymer in the base (A), and (B) the hydroxyl group content of the polyol component contained in the curing agent. And the number (NCO / OH ratio) of the hydroxyl group is selected from 1.05 to 1.25 (for example, when the NCO / OH ratio is 1.
10), (A) the amount of the prepolymer in the base,
The apparent amount of the curing agent (B) containing the required hydroxyl group content is determined, and supplied to the customer as a set after being divided into closed containers. (A) and (B) are homogeneously mixed with a sealing material mixer at a construction site, a construction site, etc., and the homogeneous mixture is used as a sealing material to perform sealing work at various joints,
After curing, if necessary, it may be painted with various commercially available paints for the purpose of hiding joints, improving aesthetics, and protecting the sealing material.

Next, the components of the present invention will be described. The polyoxypropylene diol and polyoxypropylene triol used in the (A) prepolymer component and the (B) polyol component of the present invention are polypropylene glycols having two or three functional groups. The number of functional groups means the number of functional groups of a polyether used as an initiator when propylene oxide tetrahydrofuran is subjected to ring-opening polymerization to obtain polypropylene glycol. However, the value does not include terminal unsaturated groups generated by side reactions and the like.

As the polyisocyanate used in the prepolymer component (A) of the present invention, conventionally known polyisocyanates can be used widely, for example, 2,4-toluene diisocyanate, 2,6
-Toluene diisocyanate, 4,4 ^, -diphenylmethane diisocyanate, 2,4 ^, -diphenylmethane diisocyanate, phenylene diisocyanate, polyphenylmethane diisocyanate, xylylene diisocyanate, naphthalene diisocyanate and hydrogenated compounds thereof, hexamethylene diisocyanate, isophorone diisocyanate, , 3-bisisocyanate cyclohexane, triphenylmethane diisocyanate, cyclohexyl diisocyanate, tetramethyl xylylene diisocyanate, norbornane diisocyanate, and the like. These polyisocyanates are used alone or in combination of two or more. Among these polyisocyanates, an isomer mixture of 2,4-toluene diisocyanate and 2,6-toluene diisocyanate, an isomer mixture of 4,4 ^, -diphenylmethane diisocyanate and an isomer mixture of 2,4 ^, -diphenylmethane diisocyanate, xylylene diisocyanate, and isophorone diisocyanate , Hydrogenated xylylene diisocyanate, hydrogenated diphenylmethane diisocyanate and the like are preferable, and among these polyisocyanates, 2,4-
Particularly preferred are toluene diisocyanate and isomer mixtures of 2,6-toluene diisocyanate. Note that the NCO / OH ratio is set to 1. in the relationship between the isocyanate group content of the polyisocyanate and the hydroxyl group content of the polyol.
Use in the range of 60 to 2.00.

The method for determining the NCO / OH ratio according to the present invention is performed by the following formula. "Formula for calculating NCO / OH ratio of base / hardener Here, A is the number of moles of NCO groups per 1 g of base (mol /
g) here

[KOH] = 56.1 C is the mass mixing ratio of curing agent to base 1 base / curing agent = 1 / C
"The degree of physical properties such as low modulus and high elongation means" JIS
A1439 4.21 Tensile adhesion test "and a 50% tensile stress of 0.05 N / mm ^{2 to} 0.20.
N / mm ² , a sealing material having an elongation at the maximum load of 500% or more.

[0026]

EXAMPLES <Manufacture of base> (Manufacture example 1) Bifunctional polypropylene glycol (hydroxyl value: 110, molecular weight: 1000, trade name Takerac P2)
2, 100 g of bifunctional polypropylene glycol (hydroxyl value: 56, molecular weight: 200) manufactured by Takeda Pharmaceutical Co., Ltd.
0, trade name Takerak P21, manufactured by Takeda Pharmaceutical Co., Ltd.)
500 g, trifunctional polypropylene glycol (hydroxyl value: 56, molecular weight: 3000, trade name Takerac P3
1) To 400 g of the polyol mixed solution, 165 g of toluene diisocyanate (trade name Takenate L80, manufactured by Takeda Pharmaceutical Co., Ltd.) was added and reacted at 80 ° C. for 4 hours.
An isocyanate group-terminated urethane prepolymer having a CO content of 2.9% was obtained.

(Production Examples 2 to 8) Formulation of bases shown in the following Table 1 (f: number of functional groups, 1000 to 5000: molecular weight,
PPG: Polypropylene glycol, OHV: Hydroxyl value, Number: Shows the blending amount (g) of PPG. ), 110-185 g of toluene diisocyanate (trade name Takenate L80, manufactured by Takeda Pharmaceutical Co., Ltd.) was added and reacted at 80 ° C. for 4 hours to obtain an isocyanate group-terminated urethane prepolymer having an NCO content of 1.9 to 4.0%. A polymer was obtained. In the following Table 1, Production Examples 4, 5, and 6 are examples in which the ratio of bifunctional PPG to trifunctional PPG is out of the range of Claim 1, and Production Examples 7, 8 are claims for the ratio. However, the NCO / OH ratio in the base is outside the scope of claim 1.

[0028]

[Table 1]

(Example 1) <Production of curing agent> Trifunctional PPG (OHV34, molecular weight:
5000, trade name Actcol 87-34, manufactured by Takeda Pharmaceutical Co., Ltd.) 350 g, curing catalyst (lead octylate 38)
%) 5 g, titanium oxide 10 g, heavy calcium carbonate (trade name Softon BF100, manufactured by Bihoku Powder Chemical Industry Co., Ltd.) 13
5 g, colloidal calcium carbonate (trade name, Homocal D
M, manufactured by Shiroishi Kogyo Co., Ltd.), 450 g, and a viscosity adjusting diluent (xylene), 50 g, were sufficiently mixed with a planetary mixer, rolled, and further degassed under vacuum to obtain a curing agent. Next, the base (Production Example 2) and the curing agent were mixed in a ratio of 1: 3 (weight ratio,
NCO / OH ratio of base / curing agent = 1.08), paint stain, mixability, low temperature curability, surface tack,
The foaming property, workability, tensile adhesion, and physical properties were examined.

[0030] The coating stainability is determined by filling a joint (a width of 15 mm and a depth of 8 mm) made of a slate with a sealing material sufficiently mixed with a base and a curing agent, curing the mixture at room temperature for 7 days, and applying a paint (product Name, aqueous component urethane, and please coat (all manufactured by SK Chemical Co., Ltd.) were applied with a brush and cured at room temperature for 7 days to obtain a test specimen.
After accelerated curing for 4 days, Sakurajima volcanic ash was sprinkled, and those with no adhesion of volcanic ash were rated as ○, those with slight adhesion were rated as Δ, and those with significant adhesion were rated X. The mixing property is determined by leaving the base and the curing agent in an oven at 50 ° C. overnight, adjusting the temperature, taking out the oven and immediately measuring the base and the curing agent in a ratio of 1: 3, and using a stirrer (trade name, SO Stir for 5 minutes in one direction with Samini hard mixer, L-shaped blade)
After the scraping, the mixture is further stirred in one direction for 5 minutes, and the degree of mixing of the base and the curing agent is visually inspected. If the whole is uniformly and smoothly mixed, the hardening agent remains in the shape of a circle and a slight bump without being loosened. The sample was evaluated as Δ, and the sample with the hardening agent remaining in the shape of a bump was evaluated as ×. The liquid temperature at the time of mixing was 46 to 47 ° C.

The low-temperature curability was determined by leaving the base and the curing agent in a 5 ° C. incubator overnight to adjust the temperature, and then mixing the base and the curing agent at a ratio of 1: 3 in an environmental test room set at 5 ° C. Measurement,
A sheet having a thickness of about 10 mm is prepared by mixing, and the cured state after 3 days at 5 ° C. is examined with a finger. When the rubber elasticity is sufficiently developed, the result is indicated by “、”. And those that were not restored were marked as x. The surface tack is measured by mixing the base and the curing agent in a constant temperature chamber at 23 ° C overnight after adjusting the temperature by leaving the base and the curing agent in a constant temperature room at 23 ° C. A sheet of about 10 mm in length is prepared, and the state of the surface tack after 7 days at 23 ° C. is examined with a finger, and when the tack is not felt at all, the result is ○, when the tack is felt a little, Δ, and the tack is felt strongly. Is indicated by x.

The foaming property is determined by measuring (A) the base and (B) the curing agent at a ratio of 1: 3, mixing and filling the mixture into a polyethylene container having an inner diameter of 47 mm and a depth of 15 mm, and then smoothing. After that, immediately put it in an oven at 50 ° C. and take it out after 24 hours. ○: smooth surface and almost no foaming ○, slightly foaming △, clear foaming and raised surface × And Workability is 2000-3000P in curing agent viscosity.
a. s, 3000 to 3500 Pa.s. s = 350
0 Pa. Those exceeding s were evaluated as x.

[0033] The tensile adhesiveness is determined by using a slate as an adherend,
Using "Bond Seal Primer # 7, manufactured by Konishi Co., Ltd." as a primer, and thoroughly mixing the sealing materials of Examples and Comparative Examples, two adherends slate (50 × 50) were used.
mm) and two spacers, 12 × 12
A space of × 50 mm was made, and a sealing material was filled in the space with care so as not to cause bubbles, to prepare an H-type test body shown below. Then, for this specimen,
In accordance with "JIS A 1439, 4.21 Tensile adhesion test", measure 50% tensile stress, maximum tensile stress, elongation under maximum load, and pull until the specimen breaks, breaking when broken The condition was observed.

The curing conditions of the test specimen were as follows, and the tensile test was performed at 23 ° C.・ After curing: 23 ° C x 7 days + 50 ° C x 7 days ・ After immersion: After curing + 23 ° C in water x 7 days ・ After heating: + 80 ° C x 14 days after curing Units are 50% tensile stress and Maximum tensile stress is N / m
m ² , elongation at maximum load is%. In the breakdown state, C is the cohesive failure of the sealing material, and the subscript is the failure rate (%).
Is shown.

The physical properties are too soft when the 50% tensile stress in the tensile adhesiveness is less than 0.05 N / mm ² .
If it exceeds 20 N / mm ² , it is too hard. After the curing, immersion, and heating, all test items have a 50% tensile stress of 0.05 N / mm ² or more and 0.20 / mm ² or less. ○, one of the three test items is 0.05 N / m
m ² or less than × those exceeding 0.20 N / mm ²
And

Examples 2 to 7 In the same manner as in Example 1 except that the base (Preparation Examples 1 and 3) / curing agent formulation shown in Table 2 was used, A polyurethane-based sealing material having the following results was obtained.

[0037]

[Table 2]

(Comparative Examples 1 to 12) In the same manner as in Example 1 except that the base (Preparation Example 1, Preparation Examples 4 to 8) / curing agent blend shown in Table 3 was used, The polyurethane sealing material having the result shown in No.-3 was obtained. In Table 3, Comparative Examples 1 to 5 are examples in which the molecular weight of PPG in the curing agent is out of the range of Claims 1 and 3. Comparative Example 6 is that the bifunctional PPG in the curing agent is the entire PPG. In Comparative Example 7, the NCO / OH ratio of the base / curing agent was 1.2%.
Comparative Examples 8, 9, 11, and 12 are compositions in which the curing agent is blended.
, But the base is outside the scope of claim 1. Comparative Example 10 shows the NCO / O of the curing agent and the base / curing agent.
The H ratio is within the scope of claim 1, but the base is outside the scope of claim 1. "-" In the test items in Table-3 indicates that measurement was impossible due to poor curing.

[0039]

[Table 3]

[0040]

As is evident from the above, the present invention provides a two-component polyurethane-based sealing material that can be softened by a plasticizer by comprehensively studying the combination of a prepolymer and a polyol. In areas where no hydroxyl groups remain essentially, no mixing is required, giving ease of mixing during the mixing operation, less foaming after curing, less contamination of the painted surface, lower modulus,
It is possible to provide a two-component polyurethane-based sealing material which gives high elongation properties and is excellent in low-temperature curability.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4H017 AA04 AA31 AB06 AC16 AC19 AD05 AD06 AE03 4J034 DA01 DB07 DG04 JA41 JA42 QA03 RA08

Claims (4)

[Claims] 1. The weight ratio of isocyanate group (NCO) of polyisocyanate compound (A) to polyoxypropylene diol and polyoxypropylene triol is 3 to 7:
A base composed of an isocyanate group-terminated urethane prepolymer having a hydroxyl group (OH) molar ratio (NCO / OH molar ratio) in the range of 1.60 to 2.00, and B) The weight ratio of polyoxypropylene diol to polyoxypropylene triol is 0 to 3
(A) an isocyanate group (NCO) of an isocyanate group-terminated urethane prepolymer in the base, and (B) a hydroxyl group of the polyol in the curing agent. (OH) molar ratio (NCO / OH molar ratio)
A two-component polyurethane-based sealing material which is operated at 1.25. 2. In the polyurethane-based sealing material, the number average molecular weight of the polyoxypropylene diol in the base (A) is selected from the range of 1,000 to 3,000, and the number average molecular weight of the polyoxypropylene triol is selected from the range of 3,000 to 5,000. The two-component polyurethane-based sealing material according to claim 1, wherein: 3. The polyurethane sealing material according to claim 1, wherein the number average molecular weight of the polyoxypropylene diol in the curing agent (B) is from 1,000 to 3,000, and the number average molecular weight of the polyoxypropylene triol is from 3,000 to 5,000. The two-component polyurethane-based sealing material according to claim 1 or 2, wherein: 4. The polyurethane-based sealing material according to JIS without containing a plasticizer as a compounding component.
A 1439, wherein the 50% tensile stress is in the range of 0.05 to 0.20 N / mm ² , and the elongation under the maximum load is in the range of 500% or more.
The two-component polyurethane-based sealing material according to claim 1.