JP2003171643A - Separated-application-type two-part polyurethane adhesive - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a separated-application-type two-part polyurethane adhesive which is rapid-curing, quickly develops initial tack, and develops excellent elasticity, bonding strength, heat resistance, low-temperature resistance, etc., after being cured. <P>SOLUTION: The separated-application-type two-part polyurethane adhesive is one comprising a part A and a part B and initiating a curing reaction when the parts A and B are brought into contact with each other, wherein the part A is a normally liquid solventless one mainly consisting of a compound having an isocyanate group on each molecular terminal, and the part B is a normally liquid solventless one mainly consisting of a compound having a hydroxy group in the molecule, and further containing a tertiary amine compound and/or an organotin compound. In one embodiment, the adhesive is one in which the compound having an isocyanate group on each molecular terminal is a urethane prepolymer obtained by the condensation reaction of a polyisocyanate compound with a polyether polyol. In another embodiment, the adhesive is one in which the compound having a hydroxy group in the molecule is a polyol having tertiary amine groups in the molecule. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-liquid fractional coating type urethane adhesive.

[0002]

2. Description of the Related Art A two-liquid fractional-coating type adhesive, which is generally called a honeymoon type adhesive, has two types of agents (A agent and B agent).
Agent), agent A is applied to one adherend, agent B is applied to the other adherend, and agent A and agent B come into contact when both adherends are bonded together. This is an adhesive that causes the initiation and progress of the curing reaction.

Examples of such a two-liquid fractional coating type adhesive include a cyanoacrylate adhesive composed of an agent A containing cyanoacrylate as a main component and an agent B containing a metal chloride (curing accelerator). And an acrylic adhesive (SGA) mainly composed of an acrylic monomer, an oligomer, a polymer and the like, and composed of an agent A containing a radical polymerization initiator and an agent B containing a redox polymerization catalyst. . However, these adhesives have a drawback that they are unsuitable for adhesion of portions that are likely to be distorted, because cured products are generally brittle.

Usually, for example, for bonding an outer wall panel to a base material or a metal fastener, the bonding surface between adherends moves due to a high temperature environment or vibration, and the adhesive is distorted. A so-called elastic adhesive is used.

However, urethane adhesives and modified silicone adhesives, which are widely used as elastic adhesives, take a long time to cure because they are moisture-curing adhesives, and they are different from the two-liquid separation coating adhesives. There is a problem that fast curing property cannot be obtained.

In order to address the above-mentioned problems, for example, Japanese Patent No. 2911991 discloses that (i) a reactive silicon group is present and the molecular chain is substantially (i) an alkyl group having 1 to 8 carbon atoms. A copolymer composed of the (meth) acrylic acid alkyl ester monomer unit and (ii) a (meth) acrylic acid alkyl ester monomer unit having an alkyl group having 10 or more carbon atoms, and (b) a reactive silicon group. A moisture-curable adhesive consisting of an oxyalkylene polymer having
Disclosed is a contact-type bonding method, which is characterized by allowing an adherend to be bonded within a tack range after being left for a predetermined time (taking an open time) until tack is developed.

However, the bonding method disclosed in the above publication is not a two-component separation coating bonding method, but a contact bonding method, and it requires a long open time after coating, so that the initial period from the coating It is not possible to achieve a substantial reduction in the time until the development of adhesive strength, and it cannot be said that the above problems are sufficiently solved.

[0008]

SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to be a quick-curing resin that exhibits a fast initial adhesive force, and has excellent elasticity, adhesive strength, and heat resistance after curing. (EN) It is intended to provide a two-liquid separation coating type urethane adhesive which exhibits cold resistance and the like.

[0009]

A two-liquid fractional coating type urethane adhesive of the present invention comprises an agent A and an agent B, and the agent A applied to one adherend and the other adherend. A two-liquid fractional-coating type adhesive that starts a curing reaction when it contacts the B agent applied to the above. The A agent is a liquid that is liquid at room temperature and contains a compound having isocyanate groups at both ends of the molecule as a main component. A solventless agent A, wherein the agent B is a solventless agent B which is liquid at room temperature and which contains a compound having a hydroxyl group in the molecule as a main component and further contains a tertiary amine compound and / or an organic tin compound. Is characterized in that.

The two-liquid fractional coating type urethane-based adhesive (hereinafter simply referred to as "adhesive") of the present invention comprises two liquids of agent A and agent B, and one adherend has agent A. Is applied, the agent B is applied to the other adherend, and both adherends are adhered to each other, whereby the agent A and the agent B come into contact with each other, and the curing reaction is started from that point, and the curing is promptly performed. In addition to advancing, there is no need to mix two liquids like ordinary two-liquid mixing type adhesives, so there is no need to worry about pot life after mixing two liquids, and solvent drying Since it is unnecessary, the workability is excellent.

The compound having isocyanate groups at both ends of the molecule which is used as the main component of the agent A constituting the adhesive of the present invention is the compound described later in the molecule contained in the agent B constituting the adhesive of the present invention. Any compound may be used as long as it can initiate a curing reaction promptly when it is brought into contact with a compound having a hydroxyl group and a tertiary amine compound and / or an organic tin compound described below, but is not particularly limited. Examples thereof include so-called urethane prepolymers obtained by a condensation reaction of various polyisocyanate compounds and various polyols, and are preferably used. Among them, urethane prepolymers obtained by a condensation reaction of polyisocyanate compounds and polyether polyols are preferable. Polymers are more preferably used. These compounds having isocyanate groups at both ends of the molecule may be used alone or in combination of two or more kinds.

As the above polyisocyanate compound,
Although not particularly limited, for example, aliphatic polyisocyanate compounds such as hexamethylene diisocyanate and lysine diisocyanate; alicyclic polyisocyanate compounds such as hydrogenated diphenylmethane diisocyanate and isophorone diisocyanate; tolylene diisocyanate (TDI), diphenylmethane Aromatic polyisocyanate compounds such as diisocyanate (MDI), xylylene diisocyanate, naphthalene diisocyanate, polyphenylene polyisocyanate; crude polyisocyanate compounds such as crude MDI (crude MDI) such as a mixture of MDI and polyphenylene polyisocyanate; Suitable examples include isocyanate compounds such as trimerized polyisocyanate compounds. While used, inter alia, in terms of reactivity with the polyol, MDI, crude MDI,
An aromatic polyisocyanate compound such as TDI is more preferably used. These polyisocyanate compounds are
They may be used alone or in combination of two or more.

The above-mentioned polyol is not particularly limited, but various polyols such as polyether polyol, polyester polyol, polycarbonate polyol and polymer polyol, and the above-mentioned various polyols such as castor oil (hydroxyl group-containing non-drying agent) can be used. Modified polyols such as castor oil-modified polyols modified with (oil) are preferably used, among which, among others,
A polyether polyol is more preferably used because it has excellent reactivity with the polyisocyanate compound. These polyols may be used alone or in combination of two or more kinds.

The above-mentioned polyether polyol is not particularly limited, but for example, polyethylene glycol, polypropylene glycol, polybutylene glycol, polytetramethylene glycol, etc., and random copolymers or blocks of these respective monomers. Examples thereof include copolymers. Specific examples of the above-mentioned copolymer are not particularly limited, but examples thereof include a random copolymer of tetrahydrofuran (THF) and ethylene oxide (EO), and the like.

Among the above polyether polyols,
Since they have excellent reactivity with polyisocyanate compounds, those having no side chain in the molecule such as polyethylene glycol and polytetramethylene glycol are preferably used. These polyether polyols may be used alone or in combination of two or more kinds. Further, these polyether polyols may be used in combination with polyester polyol, polycarbonate polyol, polymer polyol and the like.

The above polyisocyanate compound, preferably an aromatic polyisocyanate compound and the above polyol,
Preferably, the urethane prepolymer, which is preferably used as the main component of the agent A, can be obtained by subjecting a polyether polyol to a condensation reaction by a conventional method.

The compound having a hydroxyl group in the molecule used as the main component of the agent B constituting the adhesive of the present invention is a compound having isocyanate groups at both ends of the molecule used as the main component of the agent A, preferably Any compound may be used as long as it can quickly cure these when contacted with the urethane prepolymer and is not particularly limited, and examples thereof include polyethylene glycol, polypropylene glycol, polytetramethylene glycol and rosin. Modified polypropylene glycol, bisphenol A modified polypropylene glycol,
Examples thereof include copolymers of THF and alkylene oxides such as EO and propylene oxide, and polyols having a tertiary amine in the molecule represented by the following general formula (1).
It is preferably used, but among them, since it has excellent reactivity with a compound having isocyanate groups at both ends of the molecule used as the main component of the agent A, preferably with the above-mentioned urethane prepolymer, the following general formula (1) A polyol having a tertiary amine in the represented molecule is more preferably used. These compounds having a hydroxyl group in the molecule may be used alone or in combination of two or more kinds.

[0018]

[Chemical 7]

In the above general formula (1), R ¹ represents an alkylene chain, and the number of carbon atoms in the alkylene chain is a positive integer, preferably 2-12. As the alkylene chain,
Although not particularly limited, for example, an ethylene chain,
Propylene chains, trimethylene chains, butylene chains, amylene chains, hexylene chains and the like can be mentioned, and they are preferably used. These alkylene chains may be used alone or 2
More than one kind may be used in combination. In addition, the above general formula (1)
R ² represents an oxyalkylene chain. The oxyalkylene chain is not particularly limited, but examples thereof include homopolymers such as ethylene glycol, propylene glycol and tetramethylene glycol, and random copolymers or block copolymers thereof. It is preferably used. These oxyalkylene chains may be used alone or in combination of two or more kinds.

The compound having a hydroxyl group in the molecule is not particularly limited, but has a molecular weight of 200 to 500.
A compound having a hydroxyl value of about 0 and a hydroxyl value of about 20 to 1000, which is liquid at room temperature and has an isocyanate group at both ends of the molecule, which is used as a main component of the agent A,
It is preferable that it has excellent compatibility with the urethane prepolymer.

The agent B constituting the adhesive of the present invention contains a tertiary amine compound and / or an organic tin compound in addition to the compound having a hydroxyl group in the molecule as a main component.

The above-mentioned tertiary amine compound and organotin compound function as so-called curing accelerators and are used as the main component of the agent A. Compounds having isocyanate groups at both ends of the molecule, preferably the curing reaction of the urethane prepolymer. To contribute to the quickness.

The above-mentioned tertiary amine compound or organotin compound may be a compound which is used as a main component of the agent A and has isocyanate groups at both ends of the molecule, preferably one which can accelerate the curing reaction of the urethane prepolymer. Any compound may be used, including, but not limited to, a tertiary amine compound represented by the following structural formulas (2) to (4) or a chemical formula (5) or (6) below. The organic tin compounds and the like shown are mentioned and are preferably used. These tertiary amine compounds and organotin compounds may be used alone or in combination of two or more. Further, these tertiary amine compound and organic tin compound may be used alone or in combination.

[0024]

[Chemical 8]

[Chemical 9]

[Chemical 10]

[Chemical 11]

[Chemical 12]

The agents A and B constituting the adhesive of the present invention are liquid at room temperature and are solventless.

The agents A and / or B may be diluted with a diluent other than a solvent such as a softening agent or a plasticizer to adjust the viscosity in order to facilitate the coating operation at room temperature. Further, as the above-mentioned diluent, one having no reactivity with the compound having an isocyanate group at both ends of the molecule and / or the compound having a hydroxyl group in the molecule, or the above-mentioned tertiary amine compound and / or organotin compound It is preferable to select and use.

The above-mentioned agents A and / or B include
In addition to the respective essential components, if necessary within the range that does not hinder the achievement of the present invention, for example, a tackifying resin or a thermoplastic resin for improving initial adhesion and permanent adhesion to an adherend, filling. Agents, thixotropic agents, dehydrating agents, coupling agents, antioxidants (aging inhibitors), heat stabilizers, light stabilizers, ultraviolet absorbers, colorants, defoamers, antistatic agents,
One kind or two or more kinds of various additives such as a flame retardant may be added. Moreover, as these additives,
It is preferable to select and use a compound having an isocyanate group at both ends of the molecule and / or a compound having a hydroxyl group in the molecule, or a compound having no reactivity with the tertiary amine compound and / or the organotin compound. .

The tackifying resin is not particularly limited, and examples thereof include rosin-based resins, terpene-based resins, aliphatic petroleum resins, aromatic petroleum resins, and hydrogenated products thereof. And is preferably used. These tackifying resins may be used alone or in combination of two or more.

The softening point of the tackifying resin is not particularly limited, but the ring and ball softening point is 90 to 150 ° C.
Are preferred. The addition amount of the tackifying resin is not particularly limited, but the tackifying resin 200 is added to the compound having isocyanate groups at both ends of the molecule, preferably 100 parts by weight of the urethane prepolymer. It is preferably less than or equal to parts by weight. If the addition amount of the tackifying resin to 100 parts by weight of a compound having an isocyanate group at both ends of the molecule, preferably 100 parts by weight of the urethane prepolymer, exceeds 200 parts by weight, the cured product of the obtained adhesive will have high heat resistance at high temperature and low temperature. May have insufficient cold resistance.

The method for producing the agent A and the agent B constituting the adhesive of the present invention is not special, and may be used at ordinary temperature, for example, by using an ordinary agitating mixer such as a rotary agitator, universal mixer, kneader or the like. Under heating, if necessary under an inert gas atmosphere such as nitrogen gas or under reduced pressure dehydration atmosphere,
The agents A and B may be manufactured separately by uniformly mixing the respective predetermined amounts of the components contained in the agent A or the agent B.

When the urethane prepolymer is used as the main component of the agent A, the polyisocyanate compound and the polyol are reacted by a conventional method in a usual reactor to synthesize the urethane prepolymer, This urethane prepolymer may be used as the agent A alone, or the urethane prepolymer and other components contained in the agent A may be uniformly mixed by the above method to be used as the agent A.

The method of using the adhesive of the present invention is not special, and for example, a roll coater, a spray coater,
Applying agent A to a predetermined surface of one adherend and applying agent B to a predetermined surface of the other adherend using a conventional coating machine such as a hand gun, and then applying both adherends. Stick the faces together,
The desired bonded body can be obtained by bringing the agent A and the agent B into contact with each other, pressing them with a cold press or a heating press if necessary, and curing the adhesive at room temperature or if necessary with heating. The coating pattern at the time of coating is not particularly limited, and may be, for example, entire coating on a predetermined surface of the adherend, or partial coating such as beads, spirals, or dots. Is also good. Further, since the agents A and B are solvent-free and it is not necessary to dry the solvent, immediately after the agent A is applied to one adherend and the agent B is applied to the other adherend. The coated surfaces of both adherends may be adhered to each other to bring the agent A and the agent B into contact with each other.

The adhesive of the present invention is a two-liquid fractional coating type adhesive, but it has a composition in which the initiation and progress of the curing reaction between the agent A and the agent B are relatively slow, and the agent A and the agent B are relatively slow. If the pot life after mixing has a margin, it may be used as a two-component mixed adhesive.

[0034]

The adhesive of the present invention comprises a compound having isocyanate groups at both terminals of the molecule, preferably a urethane prepolymer obtained by a condensation reaction of a polyisocyanate compound and a polyether polyol as a main component, and a solventless liquid which is liquid at room temperature. Type A agent and a compound having a hydroxyl group in the molecule, preferably 3 in the molecule represented by the general formula (1).
A solvent-free type B agent which is liquid at room temperature and which comprises a polyol having a primary amine as a main component and further contains a tertiary amine compound and / or an organic tin compound.
Since agent A is separately applied to one adherend and agent B is applied to the other adherent without mixing agent and agent B, pot life (pot life) ) Is not restricted and the solvent does not need to be dried, and workability is excellent.

In the adhesive of the present invention, the coated surfaces of the adherend coated with the agent A and the adherend coated with the agent B are bonded to each other, and the agent A and the agent B are brought into contact with each other. As a result, the curing reaction starts immediately, so the initial adhesive force develops quickly,
Further, after finally cured, it exhibits excellent elasticity, adhesive strength, heat resistance, cold resistance and the like.

Further, since the adhesive of the present invention is not a moisture-curable type, even when adhering non-moisture-permeable large-area adherends to each other, it is excellent and uniform from the end to the center of the adherend. Develops adhesive strength.

[0037]

BEST MODE FOR CARRYING OUT THE INVENTION The following examples are given to illustrate the present invention in more detail, but the present invention is not limited to these examples.

1. A copolymer of THF and EO as a polyol (THF / EO = 7/3) as a polyol in a separable flask for the synthesis of urethane prepolymer A agent.
(Molar ratio), molecular weight: 2000, hydroxyl value: 54.7}
Add 100 parts by weight, heat and melt at 130 ° C., and 93.
The pressure was reduced to 3 kPa and dehydration was performed for 1 hour. Next, after cooling this melt to 80 ° C., 37 parts by weight of MDI (trade name “Sumijour 44S”, isocyanate group content: 33.5% by weight, manufactured by Sumika Bayer Urethane Co.) was added as a polyisocyanate compound. Under a nitrogen gas stream, 80
The reaction was carried out for 3 hours while maintaining the temperature at 0 ° C., and NCO / OH = 3.
A urethane prepolymer which was liquid at room temperature and was reacted at 0 (molar ratio) was synthesized.

2. Preparation of Polyol (Compound Having Hydroxyl Group in the Molecule), Tertiary Amine Compound, and Organotin Compound For Agent B, the following 6 types of polyol, the following 3 types of tertiary amine compound and the following 2 types of organotin compounds are prepared. did.

(1) Polyol (a) Polypropylene glycol (trade name "PP-200"
0 ", molecular weight: 2000, hydroxyl value: 54, manufactured by Sanyo Kasei Co., Ltd. (2) Polyol (b) Polyethylene glycol (trade name" PEG-400 ",
Molecular weight: 400, hydroxyl value: 280, manufactured by Sanyo Kasei Co., Ltd. (3) Polyol (c) Copolymer of THF and EO (molecular weight: 2000, hydroxyl value: 54) (4) Polyol (d) Bisphenol-modified polypropylene Glycol (Brand name "BPX-55", molecular weight: 800, hydroxyl value: 17
5, manufactured by Asahi Denka Co., Ltd. (5) Polyol (e) Polyol having a tertiary amine in the molecule represented by the general formula (1) (trade name "EDP-300", R ¹ : ethylene chain, R ² : Polypropylene glycol chain, molecular weight:
300, hydroxyl value: 760, manufactured by Asahi Denka Co., Ltd. (6) Polyol (f) Polyol having a tertiary amine in the molecule represented by the general formula (1) (trade name "BM-34", R ¹ : ethylene chain, R ^2: a block copolymer chain of propylene glycol and ethylene glycol, molecular weight: 340, hydroxyl value:
820, manufactured by Asahi Denka Kogyo Co., Ltd. (7) Tertiary amine compound (1) Tertiary amine compound (8) Represented by the structural formula (2) Tertiary amine compound (2) Represented by the structural formula (3) Tertiary amine compound (9) Tertiary amine compound (3) Tertiary amine compound (10) Organotin compound (α) represented by the structural formula (4) Organotin represented by the chemical formula (5) Compound (11) Organotin compound (β) Organotin compound represented by the structural formula (6)

(Examples 1 to 11) and (Comparative Examples 1 to 4) Respective agents A and B having the compositions shown in Table 1 were prepared,
An adhesive was prepared. The agent B was dehydrated by mixing each component, heating to 120 ° C., and stirring under reduced pressure for 1 hour.

The performance (initial shear bond strength) of the adhesives obtained in Examples 1 to 11 and Comparative Examples 1 to 4 was evaluated by the following method. The results are shown in Table 1.

Initial shear adhesive strength: At normal temperature, one zinc steel sheet was coated with the agent A and the other zinc steel sheet was coated with the agent B in a linear manner so that the coating amount was 50 g / m ² . After that, they were immediately stuck together and pressure-bonded under a pressure of 98 kPa for 30 seconds to prepare a test piece. Then, after 10 minutes, the initial shear adhesive strength (N / cm ² ) was measured. In Comparative Example 4, one zinc steel plate was only coated with the agent A and the other zinc steel plate was bonded.

[0044]

[Table 1]

As is clear from Table 1, the adhesives of Examples 1 to 11 according to the present invention all proceeded rapidly in the curing reaction and exhibited excellent initial shear adhesive strength.

On the other hand, the adhesive of Comparative Example 1 in which the tertiary amine compound and the organic tin compound were not contained in the agent B, and the comparative example in which the polyol (compound having a hydroxyl group in the molecule) was not contained in the agent B The adhesives of 2 and Comparative Example 3 all proceeded slowly in the curing reaction and had poor initial shear adhesive strength. In addition, needless to say, the adhesive of Comparative Example 4 containing only the agent A without the agent B did not proceed with the curing reaction, and the initial shear adhesive strength was poor.

[0047]

As described above, the two-part differential coating type urethane-based adhesive of the present invention is fast-curing and exhibits a high initial adhesive force, and has excellent elasticity and adhesive strength after curing. ,
It exhibits heat resistance, cold resistance, etc., and is not restricted by the pot life after mixing two liquids like a two liquid mixing type adhesive, it does not require drying of the solvent, and it has excellent workability. Therefore, for example, when the outer wall panel is adhered to a base material or metal fastener, the bonding surface between adherends moves due to high temperature environment or vibration, and the adhesive is distorted or non-permeable. It is preferably used as an elastic adhesive for adhering wet large-area adherends to each other.

Claims (4)

[Claims] 1. A two-component liquid comprising an agent A and an agent B, which starts a curing reaction when the agent A applied to one adherend and the agent B applied to the other adherend come into contact with each other. A separate coating adhesive, wherein the agent A is a solventless agent A which is liquid at room temperature and has a compound having isocyanate groups at both ends of the molecule as a main component, and the agent B has a hydroxyl group in the molecule. Having a compound as a main component, and further a tertiary amine compound and /
A two-component separation-applied urethane-based adhesive, which is a solventless B agent which contains an organic tin compound and is liquid at room temperature. 2. The two-liquid fractional coating according to claim 1, wherein the compound having an isocyanate group at both terminals of the molecule is a urethane prepolymer obtained by a condensation reaction of a polyisocyanate compound and a polyether polyol. Type urethane adhesive. 3. The two-liquid fractional coating according to claim 1, wherein the compound having a hydroxyl group in the molecule is a polyol having a tertiary amine in the molecule represented by the following general formula (1). Type urethane adhesive. [Chemical 1] (In the formula, R ¹ represents an alkylene chain, and R ² represents an oxyalkylene chain) 4. A tertiary amine compound or an organotin compound is a tertiary amine compound represented by the following structural formulas (2) to (4) and an organotin compound represented by the following chemical formula (5) or (6). The two-component separation-applied urethane-based adhesive according to claim 1, which is at least one compound selected from the group consisting of: [Chemical 2] [Chemical 3] [Chemical 4] [Chemical 5] [Chemical 6]