JPH10110155A - Two-pack urethane-based adhesive composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject composition improved in curing rate without shortening its gelling time, by formulating its curing agent with each specific polyol compound and catalyst. SOLUTION: This two-pack adhesive composition is made up of (A) the main agent containing an isocyanate group-terminated urethane prepolymer and (B) a curing agent comprising (i) a polyol compound of the formula (1nj+n2) is an integer of >=2) and (ii) dibutyltin diacetate. It is preferable that the equivalent ratio: the isocyanate group of the component A / the OH group of the component (i), namely, NCO/OH, is 1.0-2.0 and the blending proportion for the components A and B is suc:h that, for example, the component (i) is 10-100 pts.wt. or so based on 100 pts.wt. of the urethane-prepolymer in the component A.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-pack type urethane-based adhesive composition, and more particularly, to a long gelation time after mixing a base agent and a curing agent, and to shorten the curing time after bonding. The invention relates to a two-part urethane-based adhesive composition that can be used.

[0002]

2. Description of the Related Art A two-component urethane adhesive generally comprises a main agent containing a urethane prepolymer and a curing agent containing a polyol. When using a two-component urethane-based adhesive, the main agent and the curing agent are sufficiently mixed, applied to an object to be bonded, and bonded together, and the curing is progressed to adhere.

[0003] The curing of a two-pack type urethane-based adhesive is performed by curing isocyanate groups (-NC) at both ends of the urethane prepolymer.
O) reacts with the hydroxyl group (-OH) of the polyol to form a urethane bond and extend the chain, and furthermore, the generated urethane bond and the isocyanate group further react to form an allophanate bond and crosslink. proceed.
The curing reaction can be accelerated by adding a catalyst.

In order to increase the productivity when using a two-part urethane adhesive for industrial use, it is necessary to complete the curing in a short time after the adhesion. However, a urethane-based adhesive having an increased curing speed after bonding has a problem that the curing easily progresses before application. That is, the gelation time after mixing the main agent and the curing agent is short,
Even when mixing is performed using a two-liquid automatic mixer or the like, there is a problem that the curing progresses before the application, and the operation of applying the adhesive becomes extremely difficult.

As a urethane liquid curable resin composition which is cured by heat or radiation, bisphenol A is used.
The use of an ethylene oxide adduct as a polyol compound and reacting it with a polyisocyanate compound and a hydroxyl group-containing (meth) acrylate compound has been proposed (JP-A-6-80756). However, although the curing speed is high, the gelation time after mixing is short, and the balance between the gelation time and the curing time is not sufficient.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an excellent balance between the above-mentioned gelling time and adhesion time, a long gelling time after mixing a main agent and a curing agent, and a rapid curing after coating. Is to provide a two-part urethane-based adhesive composition that can be completed.

[0007]

Means for Solving the Problems The inventors of the present invention have conducted various studies to achieve the above object, and as a result, it has been found that the polyol compound and the catalyst to be compounded in the curing agent of the two-part urethane adhesive are limited to specific ones. It has been found that the curing speed can be increased without shortening the gelation time, and the present invention has been accomplished.

That is, the invention according to claim 1 provides a main agent containing a urethane prepolymer having an isocyanate group at a terminal, and a curing agent containing a polyol compound represented by the following chemical formula (1) and dibutyltin diacetate. And a two-part urethane-based adhesive composition.

[0009]

Embedded image

The invention according to claim 2 provides an equivalent ratio [NCO] / [OH] of an isocyanate group of the urethane prepolymer to a hydroxyl group of the polyol compound represented by the chemical formula (1) contained in the curing agent. But 1.0-2.0
The two-component urethane-based adhesive composition is characterized by being within the range.

Hereinafter, the present invention will be described in detail. Main Agent The urethane prepolymer used as the main agent in the present invention is not particularly limited, and a general urethane prepolymer synthesized from a polyol compound and a polyisocyanate compound can be used.

The polyol compound used for synthesizing the urethane prepolymer is not particularly restricted but includes, for example, polyester polyol, polyether polyol and polycarbonate polyol.

Further, the polyisocyanate compound used for synthesizing the urethane prepolymer is not particularly limited, and an aromatic or aliphatic organic polyisocyanate can be used. Is diphenylmethane diisocyanate (MD
I), tolylene diisocyanate (TDI), isophorone diisocyanate (IPDI), xylylene diisocyanate (XDI), hexamethylene diisocyanate (HDI) and the like.

In the present invention, the equivalent ratio [NCO] / [OH] of the isocyanate group of the urethane prepolymer to the hydroxyl group of the polyol compound represented by the chemical formula (1) contained in the curing agent is preferably , 1.0-
2.0. If the equivalent ratio [NCO] / [OH] is less than 1.0, the adhesive strength may be low,
If it exceeds 2.0, the cured film may be hard and brittle.

Curing Agent In the present invention, the polyol compound contained in the curing agent is a compound represented by the above-mentioned chemical formula (1). In the formula (1), n ₁ + n ₂ is an integer of 2 or more, and preferably, n ₁ + n ₂ is 6 to 16, and in this case, the curing agent is desirably liquid. Examples of the polyol compound satisfying the chemical formula (1) include, for example, a product name: Newpol BPE-1 manufactured by Sanyo Chemical Industries, Ltd.
00.

[0016] Dibutyltin diacetate as a catalyst contained in the curing agent in the present invention is commercially available and easily available. The amount of dibutyltin diacetate used is preferably between the urethane prepolymer and the chemical formula (1)
With respect to 100 parts by weight of the total amount of the polyol compound represented by,
0.01 to 0.1 part by weight, more preferably 0.02 to 0.1 part by weight
0.05 parts by weight. If the compounding ratio of dibutyltin diacetate is less than 0.01 part by weight, the quick-curing property after application may be impaired. May be shorter.

In the present invention, the mixing ratio of the above-mentioned main agent and the curing agent in the bonding is preferably such that the above-mentioned polyol compound in the curing agent is added to 100 parts by weight of the urethane prepolymer in the main agent. May be set to a ratio of 10 to 1,000.

Additives The two-part urethane-based adhesive according to the present invention may contain a filler, a coloring agent, a plasticizer, a stabilizer, and the like, if necessary, as long as the object of the present invention is not impaired. And may be contained in at least one of these base materials and curing agents.

The two-part urethane-based adhesive composition according to the present invention can be used for the same applications as conventional urethane-based adhesives. That is, the object to be bonded is not particularly limited, and for example, can be used for bonding members of a wide range of materials such as metal materials such as steel plates, aluminum plates, zinc plates, copper plates, and stainless steel plates, wood, and plastics. .

The two-part urethane adhesive according to the present invention comprises:
Usually distributed in a state where the main agent and the curing agent are not mixed,
It is stored and used by mixing the main agent and the curing agent at the time of use, and applying and curing the object. At the time of the mixing, a two-liquid automatic mixer or the like can be appropriately used.

The effect two-liquid type urethane-based adhesive composition according to the present invention comprises a main agent containing a urethane prepolymer having a terminal isocyanate group as described above, and the specific polyol compound, the dibutyltin diacetate Is used as a catalyst, so that the gelation time after mixing the main agent and the curing agent is sufficiently long, while the curing is completed in a short time after application and adhesion. Although the reason for this is not always clear, the combination of the polyol compound represented by the chemical formula (1) and the dibutyltin diacetate can maintain a good balance between the gelation time and the curing time after bonding. It has been found experimentally for the first time by the present inventor.

[0022]

【Example】

(Synthesis of Main Agent) Polypropylene glycol having a number average molecular weight of 1,000 (manufactured by Sanyo Chemical Industries, trade name: Sannics P
P-1000) 100 parts by weight of calcium carbonate 200
Parts by weight, mixed with stirring, dehydrated, and then treated with diphenylmethane diisocyanate (MDI) [Mitsubishi Dow,
Trade name: PAPI-135] (250 parts by weight) and reacted at 80 ° C. for 4 hours in a nitrogen stream to obtain a urethane prepolymer having a terminal isocyanate group content of 13 mol%. This urethane prepolymer was used as a main component, and was used as a main component in Example 1 and Comparative Examples 1 to 5 described later.

Example 1 1000 parts by weight of a polyol compound represented by the chemical formula (1) (manufactured by Sanyo Kasei Co., Ltd., trade name: Newpol BPE-100, n 1 ₊ n ₂ = 10 in the chemical formula (1)) 500 parts by weight of calcium and dibutyltin diacetate as a catalyst (manufactured by Sankyoki Gosei Co., Ltd., trade name: SCAT-
8) 0.5 parts by weight was added and mixed with stirring to obtain a curing agent.

To 50 g of the above-mentioned curing agent, 50 g of the above-mentioned main ingredient (urethane prepolymer) was added, mixed with stirring, and the gelation time was measured. Further, similarly, the same amount of the main agent and the curing agent is mixed, and a zinc steel plate (10 mm × 50 mm × thickness 3 m) is mixed.
m) and a slate plate (10 mm x 50 mm x 3 mm thick)
Were adhered in a cross shape, and after a lapse of a predetermined time, the steel plate and the slate plate were separated by pulling in a vertical direction, and the strength until the slate plate was broken was measured. The results are shown in Table 1 below.

Comparative Example 1 A curing agent was used in the same manner as in Example 1 except that dibutyltin dilaurate (trade name: SB-65, manufactured by Sankyoki Gosei Co., Ltd.) was used. Obtained. The gelation time was measured in the same manner as in Example 1 using the curing agent thus obtained and the main agent. Further, equal amounts of the above-mentioned curing agent and main agent were mixed and bonded in the same manner as in Example 1, and the peel strength of the slate plate after a predetermined time had elapsed was measured. The results are shown in Table 1 below.

Comparative Example 2 In the same manner as in Example 1, except that the catalyst was changed to 0.4 parts by weight of dibutyltin dilaurate (trade name: SB-65, manufactured by Sankyoki Gosei Co., Ltd.). A curing agent was obtained. Using the curing agent obtained in this way and the main agent,
The gelation time was measured in the same manner as in Example 1. Further, equal amounts of the above curing agent and main agent were mixed and bonded in the same manner as in Example 1, and the peel strength of the slate plate after a predetermined time had elapsed was measured. The results are shown in Table 1 below.

Comparative Example 3 300 parts by weight of polyethylene glycol having a number average molecular weight of 400 (trade name: PEG-400, manufactured by Sanyo Chemical Co., Ltd.) and polypropylene glycol having a weight average molecular weight of 700 (trade name: ADEKA POLY, manufactured by Asahi Denka Kogyo KK) Ether P-700)
700 parts by weight, 500 parts by weight of calcium carbonate, and 1.0 part by weight of dibutyltin diacetate (trade name: SCAT-8, manufactured by Sankyoki Gosei Co., Ltd.) as a catalyst were mixed by stirring to obtain a curing agent. The gelation time was measured in the same manner as in Example 1 using the above curing agent and the main agent. Further, equal amounts of the above curing agent and main agent were mixed and bonded in the same manner as in Example 1, and the peel strength of the slate plate after a predetermined time had elapsed was measured. The results are shown in Table 1 below. In Table 1, NCO /
The value of OH indicates the equivalent ratio of the isocyanate group of the urethane prepolymer to the hydroxyl group of the polyol compound contained in the curing agent.

Comparative Example 4 A curing agent was prepared in the same manner as in Comparative Example 3 except that the catalyst was changed to dibutyltin dilaurate (trade name: SB-65, manufactured by Sankyoki Gosei Co., Ltd.). Obtained. The gelation time was measured in the same manner as in Example 1 using the curing agent thus obtained and the main agent. In addition, the above-mentioned curing agent and the main agent were mixed in equal amounts, and adhered in the same manner as in Example 1.
After a lapse of a predetermined time, the peel strength of the slate plate was measured. The results are shown in Table 1 below. In addition, the value of NCO / OH in Table 1 shows the equivalent ratio of the isocyanate group of the urethane prepolymer to the hydroxyl group of the polyol compound contained in the curing agent.

Comparative Example 5 Calcium carbonate 8 was added to 1000 parts by weight of a castor oil modified polyol (trade name: Eurich H-52, manufactured by Ito Oil Co., Ltd.).
Then, 00 parts by weight and 0.7 parts by weight of dibutyltin dilaurate (trade name: SB-65, manufactured by Sankyoki Gosei Co., Ltd.) as a catalyst were added, followed by stirring and mixing to obtain a curing agent.

The gelation time was measured in the same manner as in Example 1 using the above-mentioned curing agent and main agent. In addition, the above-mentioned curing agent and the main agent were mixed in equal amounts, and adhered in the same manner as in Example 1.
After a lapse of a predetermined time, the peel strength of the slate plate was measured. The results are shown in Table 1 below. In addition, the value of NCO / OH in Table 1 shows the equivalent ratio of the isocyanate group of the urethane prepolymer to the hydroxyl group of the polyol compound contained in the curing agent.

[0031]

[Table 1]

In Table 1, x and に お け る in the evaluation of adhesion indicate that x did not destroy the slate plate.
○ indicates that the slate plate was broken. As is clear from Table 1, in Comparative Example 1, the polyol compound satisfying the chemical formula (1) was used as the curing agent. The gelation time at 20 ° C. was 2 minutes 30 minutes probably because dibutyltin dilaurate was used as the catalyst. Seconds were short. Therefore, although the curing speed after bonding is fast, it is easy to cure before coating,
It can be seen that workability is poor.

In Comparative Example 2, compared to Comparative Example 1,
Since the mixing ratio of dibutyltin dilaurate was small, the gelation time was increased to 3 minutes and 20 seconds, but the curing time after bonding was also increased. That is, it can be seen that the slate plate can be peeled without breaking even after 30 minutes, and the curing speed is low.

In Comparative Example 3, dibutyltin diacetate was used as the catalyst, but the gelation time was 3 minutes 30 minutes probably because the above-mentioned polyethylene glycol and polypropylene glycol were used instead of the polyol compound of the formula (1).
Although it was as long as seconds, in the evaluation of adhesiveness, it was possible to peel off the slate plate without breaking even after 40 minutes had passed.
Accordingly, it can be seen that the curing speed is low.

Also, in Comparative Example 4, as in Comparative Example 3, no polyol compound of the formula (1) was used, and in Comparative Example 4, dibutyltin dilaurate was used as a catalyst. Was as long as 3 minutes and 30 seconds, but the curing speed was even slower.

In Comparative Example 5, the above castor oil-modified polyol was used in place of the polyol compound satisfying the chemical formula (1), and dibutyltin dilaurate was used as a catalyst. Therefore, the gelation time was slightly longer at 3 minutes and 10 seconds. In the evaluation of adhesion, even after 50 minutes had elapsed, the slate plate could be peeled off without breaking, and thus a long curing time was required after adhesion.

On the other hand, in Example 1, a polyol compound satisfying the above chemical formula (1) was used as a curing agent,
Because the above dibutyltin diacetate was used as a catalyst,
When the gelation time is as long as 3 minutes and 30 seconds, and in the evaluation of adhesiveness, the slate plate is to be peeled off after 20 minutes.
The slate board has broken. Therefore, it can be seen that the curing speed after bonding is also high.

[0038]

As described above, in the two-part urethane adhesive composition according to the first aspect of the present invention, the polyol compound represented by the chemical formula (1) is used as a curing agent,
Since the catalyst containing dibutyltin diacetate is used, not only can the gelation time after mixing the main agent and the curing agent be extended, but also the curing time after applying and bonding the adhesive. Can be shortened. Therefore,
Since the gelation time is long, it is possible to perform work such as mixing before bonding with a margin, and it quickly cures after bonding, so that it is possible to increase productivity, for example, when used in industrial applications. Become.

According to the second aspect of the present invention, the isocyanate group of the urethane prepolymer contained in the main component is
Since the equivalent ratio [NCO] / [OH] to the hydroxyl group of the polyol compound satisfying the chemical formula (1) is within the above-mentioned specific range, an adhesive having an appropriate adhesive strength can be obtained.

Claims (2)

[Claims] 1. A composition comprising: a main agent containing a urethane prepolymer having an isocyanate group at a terminal; and a curing agent containing a polyol compound represented by the following chemical formula (1) and dibutyltin diacetate. Liquid type urethane adhesive composition. Embedded image 2. An equivalent ratio [NCO] / [O of an isocyanate group of the urethane prepolymer and a hydroxyl group of a polyol compound represented by the chemical formula (1) contained in the curing agent.
H] is in the range of 1.0 to 2.0, The two-component urethane-based adhesive composition according to claim 1, wherein