JPH03167286A - Moisture-curing sealing material composition - Google Patents

Abstract

PURPOSE:To obtain a one-pack moisture-curing sealing material which can exhibits excellent adhesiveness even when the open time is long and which does not require priming by mixing two specified urethane prepolymers at a specified ratio. CONSTITUTION:A moisture-curing sealing material composition which comprises a prepolymer mixture comprising a urethane prepolymer (A) obtained by reacting a polyalkylene ether triol having a molecular weight of 4,000 to 8,000 with an excess of diphenylmethane-4,4'-diisocyanate and a urethane prepolymer (B) obtained by reacting a polyalkylene ether diol or polyalkylene ether triol having a molecular weight of 2,000 to 6,000 with an excess of tolylene diisocyanate at a weight ratio of A to B of (95:5) to (70:30).

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a moisture-curing sealant composition, more specifically, a one-liquid type moisture-curing sealant composition which can be applied, for example, to the sealing of automobile bodies, and is particularly suitable for use on painted surfaces or The present invention relates to a urethane sealing material composition that can exhibit sufficiently excellent adhesion even when an oven time of 10 minutes or more is applied to brass, thereby eliminating the need for brimer treatment.

Prior Art and Problems to be Solved by the Invention ■ Liquid-type urethane-based moisture-curable urethane sealing material compositions are sealing material compositions that are cured by the reaction between isocyanate groups in the composition and moisture (moisture) in the air. It has excellent performance.

However, when the sealant composition is cured, carbon dioxide gas is generated due to the reaction between isocyanate groups and moisture, and this is especially true for l-component moisture-curable urethane sealant compositions that have a fast curing speed. Carbon dioxide gas bubbles tend to form inside the object or near the interface between the object and the adherend, which has a negative effect on the sealing effect, strength, and adhesion to the adherend, and this tendency becomes stronger as the temperature and humidity increase. There is a need for the development of a sealant composition that does not have these drawbacks.

For example, it has been proposed to use a one-component moisture-curable urethane sealant composition when attaching an automobile windshield to a car body using an adhesive sealing method.
Generally, assembly lines are used in automobile production plants, and the distortion of the car body due to movement to each process after the windshield is installed,
To withstand vibrations, air pressure shocks caused by door opening/closing, shower tests for water leakage inspection, etc., and to achieve good sealing effects and strong adhesion, a one-component type of moisture that cures quickly and does not foam even under high temperature and humidity conditions. A curable urethane sealant composition is required.

By the way, as a sealing material composition that meets such requirements, for example, the molecule ffi5000-8000
A moisture-curable sealant composition containing a urethane brevolimer obtained by reacting a polyalkylene ether triol with an excess amount of an aromatic diisocyanate compound is already known (see Japanese Patent Publication No. 8155/1983). This sealant composition is fast-curing, does not foam even under high temperature and humidity, and has good workability and storage stability.
Although extremely useful, it has poor adhesion to painted surfaces.
If the oven time (i.e., the time from application of the sealant to bonding) is long (generally 5 minutes or more), the adhesive strength tends to be insufficient, which is why primer treatment is necessary.

Furthermore, JP-A No. 59-78227 discloses a polyalkylene ether triol having a molecule i5000 to 7000 and a polyalkylene ether diol having a molecule iiooO to 4000 as a sealing material composition with particular consideration to viscosity adjustment and storage stability. Urethane brevolomer (X) obtained by reacting the above mixed polyol with an excess amount of tolylene diisocyanate, and the above mixed polyol obtained by reacting an excess amount of diphmenylmethane-4,4°-diisocyanate. Moisture-curable sealant compositions containing a mixed prepolymer consisting of urethane brevolomer (Y) are described. Although this sealant composition also satisfies the above requirements, its two main components, urethane bleb polymers (X) and (Y), are both polyalkylene ether triol and polyalkylene ether triol. It is a product in which a specific diisocyanate compound is reacted with a mixed polyol of diols, and various products are produced during this reaction, for example, schematically, ■ 00NNCO ■ H? ! There is a possibility that the raw wood has an I structure as shown by OCN AANNCO - NCO, and it is assumed that this is the reason for the variation in physical properties.

Therefore, the present inventors took into consideration the problems of such known compositions and carried out intensive studies to solve the problems, and found that two types of urethane obtained by the reaction of a specific triol component or diol component and a diisocyanate component. It was discovered that by combining Brevolimer, a moisture-curable sealant composition that satisfies the desired requirements and eliminates the problems of reduced adhesion and physical property variations due to open time can be obtained, and the present invention was completed. reached.

Structure and Effects of the Invention Namely, the present invention provides a urethane blend obtained by reacting a polyalkylene ether triol with a molecular weight of 4000 to 8000 and an excess amount of diphenylmethane-4.4°-diisocyanate (hereinafter referred to as MDI). Bolimar (
A), and a polyalkylene ether diol or polyalkylene ether triol with molecules ffl2 0 0 0 to 6000 and an excess amount of tolylene diisocyanate}
・In a moisture-curable sealant composition containing a mixed prepolymer consisting of a urethane bleed polymer (B) obtained by reacting the urethane bleed polymer (A) and the urethane bleed polymer (hereinafter referred to as TDI), (B)
The present invention provides a moisture-curable sealant composition characterized in that the mixing weight ratio of 95=5 to 70:30.

The urethane prepolymer (A) in the present invention is produced by reacting polyalkylene ether triol with an excess amount of MDI, for example, at a molar ratio of NCO/OH of 1.5 to 2.5. free NGO
The content is set at 1.5-2.5% by weight. In the reaction, a catalyst for accelerating the reaction (addition ffl 0.1 to 0.5% by weight) such as dibutyltin dilaurate, dibutyltin maleate, stannous octate, lead octate, and tertiary amine may be used.

In addition, the obtained urethane prepolymer may be used as is, but the crosslinking reaction between free NGOs and urethane bonds (allophanate bond biochemical reaction) and the reaction between free NGOs (multimerization reaction) are suppressed, and storage stability is improved. In order to improve the performance, the remaining free NGO may be blocked with an active methylene group-containing compound. Examples of such active methylene group-containing compounds include dialkyl malonates such as dimethyl malonate, diethyl malonate, and methyl ethyl malonate, and acetoacetic acid alkyl esters such as methyl acetoacetate and ethyl acetoacetate.

The polyalkylene ether triol is produced by addition polymerization of an alkylene oxide such as ethylene oxide or propylene oxide and an active hydrogen compound such as glycerin or trimedylolpropane, and has a molecular ffi of 4000 to 8000, preferably 5000 to 70.
00 is used. If the molecular weight is less than 4,000, the modulus increases in terms of physical properties, making it difficult to achieve appropriate elongation, while if it exceeds 8,000, the degree of unsaturation of the polyol increases and impurities such as monools increase (the average number of functional groups decreases). , the desired prepolymer cannot be obtained.

As such a triol, ethylene oxide (hereinafter referred to as
Polypropylene ether triol with an addition molar loss of 20 mol % or less (referred to as EO) is preferred; if the EO addition molar number exceeds 20 mol %, improvements in adhesion and curing speed can be seen, but a new problem of foaming occurs. It tends to occur in

The urethane prepolymer (B) in the present invention is made of a polyalkylene ether triol or a polyalkylene ether diol and an excess amount of TDI, as in the case of the urethane prepolymer (A), if necessary in the presence of a catalyst for promoting the reaction. Produced by reaction at a molar ratio of NCO/OH of 1.5 to 2.5, and containing NCO! 1.5-2.5
It is set to heavy burial mound%. When used, it may be blocked with an active methylene group-containing compound as described above.

The polyalkylene ether triol or polyalkylene ether diol has a molecular weight of 2000 to 6.
000, preferably 3000 to 6000. If the molecular weight is less than 2,000, the required elongation cannot be obtained, and if it exceeds 6,000, the elongation becomes significantly large and, accordingly, the desired strength tends to be unsatisfied.

As such a triol or diol, a polypropylene ether triol or diol having an EO addition mole number of 20 mol % or less is preferable.

Here, two types of urethane prepolymers (B) using triols or diols are shown, but each of these may be used alone or in combination.

The moisture-curable sealant composition according to the present invention can be purchased by containing a mixed prepolymer of the above-mentioned urethane prepolymer (A) and urethane bleb polymer (B). The mixing ratio of urethane prepolymer (A) and urethane brebolymer (B) is 95:5 to 70:30 by weight,
Preferably, the ratio is selected within the range of 90:10 to 80:20.

If the ratio of urethane brevolomer (A) is less than 70, the curing speed will decrease, and if it is more than 95, the adhesiveness will be insufficient.

If necessary, fillers (carbon black such as furnace black and thermal black, calcium carbonate, calcined kaolin, clay,
talc or mixtures thereof), plasticizers (such as talc or mixtures thereof), plasticizers (such as G2
- Phthalic acid esters such as ethylhexyl phthalate, butylbenzyl phthalate, dinonyl phthalate, benzoic acid esters such as diethylene glycol dibenzoate, ethylene glycol monobutyl ether benzoate, partially hydrogenated terphenyl, alkyl polycyclic aromatic hydrocarbons chlorinated paraffins, or mixtures thereof), solvents (aromatic solvents such as toluene and quinolene, esters, ketones, ethers, etc.), catalysts for accelerating curing (N-alkylbenzylamine, N-alkyl tertiary amines and other nitrogen-containing compounds such as morpholine, N-alkyl aliphatic polyamines, N-alkyl biverazine, triethylenediamine, ■,8-biazacyclo[5.4.0]undecene-7 and its derivatives; Added fIO.1 to 1.0% by weight of heavy metal organic compounds such as naphthenic acid or octenoate of heavy metals such as zinc, tin, lead, bismuth, cobalt, manganese, iron, and mercury, dibutyltin dilaurate, dibutyltin maleate, etc. ) etc. may be blended in appropriate amounts.

The composition of the present invention having the above structure has a fast curing speed,
It does not foam even under high temperature and high humidity conditions, exhibits low viscosity, and has good dispensing properties and storage stability. It exhibits excellent adhesion, especially to painted surfaces or plastics, even when open time is longer than tO minutes. This eliminates the need for brimer treatment.

Next, the present invention will be explained in more detail with reference to Production Examples, Examples, and Comparative Examples.

Manufacturing example! (Triol/MDI) Molecule 1i17000 polyoxypropylene ethylene triol (EO mole number 15 mol%) 300
0g was put into a reaction tank purged with nitrogen and heated under vacuum (10f).
After confirming that the moisture content of the contents is 0.05% (by weight, the same applies hereinafter) or less, MDI (370 g) is added to it, and the temperature is lowered to 8.
Stir for 30 minutes under vacuum while adjusting the temperature to 0±5°C. 30
After a few minutes, the pressure was returned to normal with nitrogen gas, a 1% toluene solution of dibutyltin dilaurate (1 g) was added, and the mixture was heated under vacuum again for 4 hours.
React for a time (80±5°C). After the reaction is cooled, the free NCO content is 2.2% and the viscosity is 45000 cps/
Obtain a urethane prepolymer at 20°C.

Production example 20 liol + diol/MDI) molecule @ 7 0
0 0 polyoxypropylene ethylene triol (
200 of (15 mol% EO moles) was charged into a reaction tank purged with nitrogen, and further boroxypropylene diol (0 mol% EO moles) with a molecular weight of 3000 was added.
After adding 9, MDI was added in the same manner as in Production Example 1.
(4299) was reacted with free NGO containing ffi2.3.
% and a viscosity of 55000 cps/20°C.

Production Example 3 (Triol/TDI) After charging boroxypropylene triol (EO mol loss 1O mol %) with a molecular fi of 5 0 0 0 to a reaction tank purged with nitrogen, the same operation as in Production Example 1 was carried out. TDI (a mixture of 2.4-tolylene diisocyanate and 2.6-}lylene diisocyanate, hereinafter 2939) was reacted with fl12.
A urethane prepolymer of 1% and a viscosity of 11000 cps/20° C. is obtained.

Production Example 4 (Diol/TDI) Polyoxypropylene diol (EO
After putting 300 ot (mol%) into a reaction tank purged with nitrogen, TD was added in the same manner as in Production Example 1.
I (2 9 89) to react with free NCO-containing f
fi2.0%, viscosity 15000cps/20
Obtain the urethane prepolymer at °C.

Production example 5 (triol + diol/TDI) molecule f71
5000 polyoxypropylene triol (E
O mole number 10 mol%) 2 0 0 09 and molecular weight 300
After charging 10,009 boroxypropylene diol (EO mol %, O mol %) into a reaction tank purged with nitrogen,
Next, TDI (3169) was reacted in the same manner as in Production Example 1 to obtain a free MNCO content of 2.3% and a viscosity of 16000c.
A urethane prepolymer having a temperature of ps/20° C. is obtained.

Examples 1 to 4 and Comparative Examples 1 to 7 Using the urethane prepolymers obtained in Production Examples 1 to 5, they were mixed in the parts by weight shown in Table 1 below, and 4509 was put into a stirring pot purged with nitrogen. Then, 300 g of dehydrated di-2-ethylhexyl phthalate was added.

Both components are mixed by stirring under a nitrogen atmosphere, and then dried carbon black 5502 and dried calcium carbonate 3009 are gradually added. After the addition, after stirring for 30 minutes under vacuum (10 mmHg or less) for degassing, 80 g of xylene for viscosity adjustment and 0.5 g of dibutyltin dilaurate as a catalyst for curing promotion were added, and after stirring under vacuum for 10 minutes, the obtained product was obtained. The sealant composition is dispensed into a sealed aluminum cartridge. Table 1 shows the performance of these sealant compositions.

Note) The test method is as follows.

(1) Second visual inspection (2) Viscosity: Measured at 25°C using a McMichael meter (3) Tack-free time at curing rate = 20°C, relative humidity 65% (4) Time: 35°C, Limit oven time (minutes) for good coating adhesion in an atmosphere of 95% relative humidity (5) Elongation, tensile strength and hardness: 7 days at 20°C and 65% relative humidity After curing, measure according to JISK-630 (6) Storage stability: Observe the state after storage at 40°C for 30 days under sealed conditions. From the results in Table 1, the sealant compositions of Examples 1 to 4 were However, in Comparative Examples 1 and 2, the open time was too fast, and in Comparative Examples 3 to 7, the curing speed was slow and the tensile strength decreased.

Claims (1)

[Claims] 1. Polyalkylene ether triol having a molecular weight of 4,000 to 8,000 and an excess amount of diphenylmethane-4,4'-
It consists of a urethane prepolymer (A) obtained by reacting a diisocyanate, and a urethane prepolymer (B) obtained by reacting a polyalkylene ether diol or polyalkylene ether triol with a molecular weight of 2000 to 6000 with an excess amount of tolylene diisocyanate. In a moisture-curable sealant composition containing a mixed prepolymer, the above-mentioned urethane prepolymer (A) and urethane prepolymer (
A moisture-curable sealant composition characterized in that the mixing weight ratio of B) is 95:5 to 70:30. 2. The polyalkylene ether triol or polyalkylene ether diol in the urethane prepolymers (A) and (B) has an ethylene oxide addition mole number of 20
The moisture-curable sealant composition according to claim 1, which is polypropylene ether triol or polypropylene ether diol in an amount of mol % or less.