JP3436865B2 - Method for producing adhesive composition and decorative sheet covering material - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a solvent-based adhesive composition containing at least one thermoplastic resin as a resin component and a polyisocyanate compound as a curing agent, and an adhesive composition thereof. The present invention relates to a main component for a two-component adhesive and a method for producing a decorative sheet coating material using the above-mentioned adhesive composition.

[0002]

2. Description of the Related Art Solvent-based adhesives composed of a base resin prepared by dissolving a thermoplastic resin, particularly a polyurethane resin and a polyester resin in a solvent, and a polyisocyanate curing agent show good adhesiveness to a wide range of materials, and various plastics. It is used for bonding a wide range of materials such as metal, wood and wood.

When a decorative sheet is coated and bonded on a curved surface with this type of adhesive, the adhesive is applied to the back surface of the decorative sheet by a T die coat, so that the adhesive pot of the T die coat is used. It will stay for several hours.
Therefore, in order to maintain the stability at the time of retention, it is necessary to extend the pot life, and therefore, a general-purpose catalyst or the like is not usually added. As a result, the reaction of isocyanate after coating and adhesion, that is, the curing speed is slow, and it takes 10 hours or more until the predetermined performance is exhibited. That is, when manufacturing a decorative sheet coating material using this type of conventional adhesive, it takes more than the second half of the process end until the product inspection of the final product is started, and from the start of production to the end of the product inspection, It takes more than a day even if it is manufactured as quickly as possible. Therefore, there is a problem that the stock of work-in-process increases and product shipment is delayed.

However, when a catalyst such as an organic metal salt or a tertiary amine is added for the purpose of shortening the curing time, the pot life becomes very short, and the workability in the above process is remarkably deteriorated. That is, it is very difficult to balance the curing speed and the pot life, and if the curing speed is adjusted to the desired value, the pot life becomes shorter, and if the pot lives are adjusted, the curing speed may not reach the desired speed. Many.

Therefore, the curing of isocyanate is accelerated,
Moreover, as a technique for maintaining a long pot life, polyamine is reacted with a ketone to form a ketimine, and its reactivity is lowered, so that the pot life is lengthened, and after being applied to a substrate, it is treated with water, A coating method has been proposed in which ketimine is returned to the original polyamine and ketones to cause a high-speed reaction between an isocyanate group and an amine (for example, JP-A-61-120862). Also, a coating method has been proposed in which a water-based paint is applied to the surface instead of treating with water in the above (for example, JP-A 1-1).
27086).

[0006]

However, since all the techniques are not related to the bonding method but to the coating method, there are various problems as described below when applied to the bonding method. In other words, water treatment or application of a water-based adhesive after applying the adhesive not only increases the number of steps and materials used, but also causes a problem of adhesive strength at the interface and adversely affects the object to be adhered. Is concerned.

In order to solve the above problems, an object of the present invention is to provide an adhesive composition which has a long curing time after coating and adhesion, and a main component thereof, which has a long pot life without changing the conventional adhesion process. The present invention provides a component and a method for producing a decorative sheet coating material using this adhesive composition.

[0008]

Means for Solving the Problems The inventors of the present invention have made extensive studies on the adhesive composition in order to solve the above-mentioned problems.
The inventors have found that the adhesive composition as described above can be obtained by combining a trialkanolamine, which is a specific curing catalyst, and a ketimine compound, and have completed the present invention.

That is, a characteristic constitution of the adhesive composition of the present invention is that a solvent-based adhesive composition containing one or more thermoplastic resins as a resin component and a polyisocyanate compound as a curing agent, The point is that it contains a ketimine compound and a trialkanolamine.

In the above description, various compounds can be exemplified as the trialkanolamine as described below, but it is preferable that the trialkanolamine is triethanolamine in view of the action and effect described below.

In the above, the content of the ketimine compound is 0.2 to 100.0 parts by weight, and the content of the trialkanolamine is 0.1 to 10% with respect to 100 parts by weight of the polyisocyanate compound. The amount of 0 parts by weight is more preferable than the effects described later.

Further, the adhesive composition of the present invention can contain various components used in ordinary solvent-based adhesives, but it is more preferable to further contain a tackifier in view of the function and effect described later.

Further, as the thermoplastic resin, various kinds of thermoplastic resins soluble in a solvent can be used, but it will be described later that the thermoplastic resin is mainly a polyurethane resin or a polyester resin. It is more preferable than the effect.

On the other hand, although the adhesive composition of the present invention is finally mixed and used in one liquid, it is often supplied to the customer in two or more liquids. At that time, among the mixed components, the main component is the main component of a solvent-based adhesive containing at least one kind of thermoplastic resin as a resin component, and contains a ketimine compound and a trialkanolamine. It is a thing.

On the other hand, the characteristic constitution of the method for producing a decorative sheet coating material of the present invention is that one of the above-mentioned adhesive compositions is applied to the back surface of a decorative sheet, dried, and coated on a base material to be adhered. In point.

[Advantageous Effects] According to the adhesive composition of the present invention, as shown by the results of Examples described later, since it contains a ketimine compound and a trialkanolamine, the conventional adhesive step is It is possible to increase the curing speed after coating and adhesion while extending the pot life without changing. Although the details of the reason are not clear, it is considered as follows. That is, when the trialkanolamine is used alone in the adhesive, the addition of a large amount so that the curing speed will be sufficient will shorten the pot life, and conversely, the addition of a small amount so that the pot life will be sufficient will result in curing. Insufficient speed. However, in the single use of a ketimine compound which is a compound that hydrolyzes to produce a primary amine or a secondary amine, the pot life is shortened similarly when a large amount is added, but with a small amount, the pot life is lengthened, In some cases, the creep property after application of the adhesive can be improved by the reaction with the water contained in the adherend and the like. That is the case where the adhesive is applied at the beginning of the pot life, but when the adhesive is applied at the latter stage of the pot life,
The trace amount of water contained in the adhesive consumes the ketimine compound during the pot life, resulting in insufficient creep characteristics after application of the adhesive. Therefore, in the latter half of the pot life, it is necessary to improve the creep characteristics after application of the adhesive, but by using a trialkanolamine in combination within the range where the problem of the pot life does not occur, the amine produced by the hydrolysis of the ketimine compound is Since the reaction of the trialkanolamine becomes dominant in the presence of, the creep characteristics are improved even when the adhesive in the later stage of pot life is applied. Therefore, it is considered that the curing speed after coating and adhesion can be increased while extending the pot life.

When the trialkanolamine is triethanolamine, the above-mentioned action and effect are remarkably improved by the cooperative action of the two, as will be shown by the results of Examples described later.

In the above, if the content of the ketimine compound is less than 0.2 parts by weight with respect to 100 parts by weight of the polyisocyanate compound, the amount of amine produced will be small and the curing speed will tend to be insufficient. There is. On the other hand, when the content of the compound exceeds 100.0 parts by weight, the reaction with a small amount of water tends to be accelerated and the pot life tends to be shortened. Further, the content of the trialkanolamine is 0.
If it is less than 1 part by weight, the contribution to the above mechanism tends to be small. On the other hand, if the content of the trialkanolamine exceeds 10.0 parts by weight, the curing reaction tends to be too fast before the adhesion and the pot life tends to be shortened.

Further, when the tackifier is further contained, the adhesive strength and adhesiveness at the initial stage are higher than those in the case where the tackifier is not contained.

When the thermoplastic resin is mainly composed of polyurethane resin or polyester resin, since it has a polar group, it can exhibit good adhesiveness to a wide range of materials.

According to the main component of the adhesive of the present invention, the effects of the adhesive composition of the present invention as described above can be obtained simply by mixing the polyisocyanate curing agent with the main component. In other words, the above-mentioned mechanism could provide the main component of the adhesive composition, which makes it possible to increase the pot life and increase the curing rate after coating and adhesion, without changing the conventional adhesion process.

According to the method for producing a decorative sheet coating material of the present invention, any one of the above adhesive compositions is applied to the back surface of the decorative sheet, dried, and coated on a base material to be adhered. The above-mentioned effects can be obtained when the is adhered to the substrate. That is, to provide a method for producing a decorative sheet coating material with improved workability and work efficiency by increasing the curing speed after application and adhesion while extending the pot life without changing the conventional adhesion process. I was able to.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below. The adhesive composition of the present invention is a thermoplastic resin.
The thermoplastic resin that contains at least one species as a resin component includes a polyurethane resin, a polyester resin, a chloroprene resin, an acrylic resin, and the like, but a polyurethane resin or a polyester resin is preferable from the viewpoint of the above-mentioned effects. . The content of the thermoplastic resin is preferably 5 to 100 parts by weight, and 10 to 40 parts by weight, relative to 100 parts by weight of the solvent, in consideration of the drying rate of the solvent.
More preferably parts by weight.

The adhesive composition of the present invention is a solvent-based adhesive composition, but as a solvent, if it dissolves the above resin, has a certain volatility, and is inert to the reaction in the present invention. Any of these can be used. Specific examples include methylene chloride, acetone, toluene, MEK, ethyl acetate and the like.

As the polyisocyanate compound used as the curing agent, any polyisocyanate compound can be used as long as it does not particularly inhibit the above-mentioned action mechanism, and examples thereof include tolylene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, and trilylene diisocyanate. Aliphatic polyisocyanates such as phenylmethane triisocyanate, hexamethylene diisocyanate, aliphatic polyisocyanates such as 2,2,4-trimethylhexamethylene diisocyanate, isophorone diisocyanate, hydrogenated tolylene diisocyanate, alicyclic such as hydrogenated diphenylmethane diisocyanate Examples thereof include polyisocyanate. These may be used alone or in admixture of two or more. The content of the curing agent is preferably 10 to 50 parts by weight, and more preferably 15 to 35 parts by weight, based on 100 parts by weight of the thermoplastic resin, in consideration of the curing speed and the physical properties after curing.

Examples of the ketimine compound used include compounds obtained by condensation reaction of polyamine and ketones. Examples of such polyamines include ethylenediamine, propylenediamine, butylenediamine, hexamethylenediamine, xylylenediamine,
Polyoxypropylene diamine, bis (aminomethyl)
Cyclohexane, methylenebis (cyclohexylamine), 3-aminomethyl-3,5,5-trimethylcyclohexylamine, 1-methyl-2,4-diaminocyclohexane, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, etc. Can be mentioned. In addition, a polyamidoamine obtained by reacting an excess amount of these polyamines with a polybasic acid such as succinic acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, and dimer acid can also be used as the polyamine. Further, those obtained by reacting these polyamines with an epoxy compound to form an amine adduct or reacting with an isocyanate compound or a urethane prepolymer to form a urea group-containing polyamine can also be used.

Examples of the ketones include aliphatic, aromatic and alicyclic ketones such as acetone, methyl ethyl ketone, diethyl ketone, methyl isobutyl ketone, diisobutyl ketone, cyclohexanone, acetophenone and benzophenone. The reaction between the above polyamine and ketones is carried out in a solvent or without a solvent at about 0-25.
It is carried out at 0 ° C.

The mixing ratio of the ketimine compound is the same as that of the polyisocyanate compound 10 because of the reason described in the above function and effect.
0.2 to 100.0 parts by weight is preferred, 0 to 80 parts by weight is more preferred, and 5 to 60 parts by weight is even more preferred, based on 0 parts by weight.

Further, a substance important in the present invention is trialkanolamine which also serves as a urethane curing catalyst, and triethanolamine, trimethanolamine and the like are used in the present invention. The content of trialkanolamine is preferably 0.1 to 10.0 parts by weight, more preferably 1.0 to 4.0 parts by weight based on the polyisocyanate compound for the reason described in the above-mentioned effects. .

Further, in order to impart initial strength and adhesiveness,
Tackifying resins are often used. As these tackifying resins, terpene resins, phenol resins, terpene phenol resins, rosin resins, xylene resins, ketone resins, acetophenone formaldehyde resins, hydrogenated resins thereof, and the like are used. These may be used alone or in combination of two or more.

Further, the adhesive composition of the present invention may contain various additive components which are appropriately contained in the same kind of adhesive, and various adhesive properties such as a silane coupling agent depending on the requirements of these systems. An imparting agent, a filler typified by calcium carbonate, a pigment, a stabilizer, and the like can be appropriately contained.

The adhesive composition of the present invention can be manufactured by mixing the above components. However, it is necessary to prepare in advance a main component other than the curing agent and mix the curing agent before use. Is preferable in terms of workability. That is, the main component for obtaining the action and effect of the adhesive composition of the present invention is a mixed component of a solvent-based adhesive containing one or more thermoplastic resins as a resin component, and a ketimine compound, and The thing which further contains a trialkanol amine is mentioned.
In addition, these various components and content are as above-mentioned.

Next, the method for producing the decorative sheet coating material of the present invention will be described. As the decorative sheet used to coat the substrate, vinyl chloride resin, vinylidene chloride resin, polyester resin, ethylene-vinyl acetate copolymer resin sheet, wood veneer and synthetic resin impregnated veneer sheet, aluminum Metal foil such as foil, paper, cloth and the like are used. As the substrate to be coated, various wood materials,
Examples of the material include metal materials, coated metal materials, various synthetic resin materials, and the like. Materials such as wood materials that contain water are preferable for shortening the curing time.

Examples of the method for applying the adhesive composition include a method using a T die coater, a knife coater, a spray coater, etc., and the coating film thickness is about 50 to 150 μm. The coating film is dried to dry the solvent to a certain extent.
A method of heating and drying at about ° C can be mentioned. In addition, for coating and adhering to the base material, pressure bonding using a roll or the like is used.

[0035]

EXAMPLES Hereinafter, examples and comparative examples of the present invention will be described in detail while showing their effects. However, these do not show all the findings in the present invention, and the present invention is not limited to the examples. It is not limited.

Examples 1 to 4 A thermoplastic urethane resin (Desmocol 400, manufactured by Bayer) and a tackifying resin (phenolic resin, Tamanol 100S, manufactured by Arakawa Chemical Industry Co., Ltd.) were dissolved in methylene chloride,
A solution having a solid content of 25% was prepared, and triethanolamine and a ketimine compound (Hardener EH235R,
Ketimine obtained from polyether-based diamine and MIBK, manufactured by Asahi Denka Kogyo Co., Ltd., was added to prepare a main component of an adhesive having the composition shown in Table 1. Prior to adhesion, 5 parts by weight of a curing agent (MDI, dismod
10, manufactured by Sumitomo Bayer Co., Ltd.) was added and stirred to obtain an adhesive composition of the present invention. This adhesive composition was applied to a PVC decorative sheet with an applicator to a thickness of 100 μm, and dried at 40 ° C. for 30 seconds. Immediately after drying, the decorative sheet coated with this adhesive was attached to a semi-rigid fiber board and pressure-bonded with a pressure roller. The adhesive composition used had a pot life of the first half (immediately after production) and the second half (about 60 minutes after the production).

As a method for evaluating the adhesive, pot life and heat-resistant creep after 1 hour were used. The pot life is measured by blending a predetermined amount of the main agent and curing agent kept at 20 ° C, the viscosity immediately after is taken as the initial viscosity, and the time at which the viscosity doubles when left at 20 ° C and RH 60%. It was life. 60 minutes or more was passed. In the heat resistance creep test, the decorative material bonded by pressure is left for 1 hour at 20 ° C. and RH 60%, then the PVC sheet is cut into a width of 25 mm, and peeled at 90 ° under a load of 500 g / 25 mm, and a heat resistance of 60 ° C. The test was conducted. As a result, 5m
A creep of m or less was accepted. The results are shown in Table 1.

[0038]

[Table 1]

Comparative Examples 1 and 1'Adhesive compositions were prepared in the same manner as in Examples 1 and 3 except that the ketimine compound was not used in Examples 1 and 3, and pot life and after 1 hour Thermal creep was tested.

Comparative Example 2 An adhesive composition was prepared in the same manner as in Example 2 except that triethanolamine was not used, and pot life and heat-resistant creep after 1 hour were tested.

Comparative Example 3 Example 4 was repeated except that 0.5 parts by weight of an amine catalyst (Dismorapid 10/9, manufactured by Sumitomo Bayer Ltd.) was used in place of the ketimine compound and triethanolamine in Example 1. In the same manner as in 1, prepare an adhesive composition,
Pot life and heat-resistant creep after 1 hour were tested.

Comparative Example 4 In Example 1, except that 1 part by weight of an organometallic catalyst (dibutyltin dilaurate, DBTDL) was used instead of the ketimine compound and triethanolamine.
An adhesive composition was prepared in the same manner as in Example 1 and tested for pot life and heat creep after 1 hour.

The results of the above comparative examples are shown in Table 2.

[0044]

[Table 2] When the heat-resistant creep is "impossible", it means that the adhesive cannot be adhered due to an increase in viscosity.

As shown by the results in Table 1, in the examples of the present invention in which the ketimine compound and triethanolamine were used in combination, both the pot life and the heat-resistant creep after 1 hour were excellent. On the other hand, in the case of using only triethanolamine (Comparative Examples 1 and 1 '), heat-resistant creep was insufficient in both the first and second stages with an appropriate pot life, and only the ketimine compound was used. In the case of using (Comparative Example 2), heat resistance creep in the latter period was insufficient when the pot life was appropriate. Further, in both cases of using an amine-based catalyst (Comparative Example 3) and using an organometallic catalyst (Comparative Example 4), the pot life was shortened when an appropriate heat-resistant creep value was obtained.

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-4-300957 (JP, A) Keiji Iwata “Polyurethane Resin Handbook” September 25, 1987, Nikkan Kogyo Shinbun, No. 118- 121 (58) Fields investigated (Int.Cl. ⁷ , DB name) C09J 4/00-201/10 C08G 18/00-18/87 B32B 27/00-27/42

Claims (6)

(57) [Claims] 1. A solvent-based adhesive composition containing at least one thermoplastic resin as a resin component, a polyisocyanate compound, a ketimine compound, and a trialkanolamine as a curing agent. 2. The adhesive composition according to claim 1, wherein the trialkanolamine is triethanolamine. 3. The content of the ketimine compound is 0.2 to 10 relative to 100 parts by weight of the polyisocyanate compound.
The adhesive composition according to claim 1 or 2, wherein the amount is 0.0 parts by weight, and the content of the trialkanolamine is 0.1 to 10.0 parts by weight. 4. The method according to claim 1, further comprising a tackifier.
The adhesive composition according to any one of 1. 5. The thermoplastic resin is mainly composed of a polyurethane resin or a polyester resin.
The adhesive composition according to any one of to 4. 6. The adhesive composition according to any one of claims 1 to 5 is applied to the back surface of a decorative sheet, dried, and coated on a base material to be adhered thereto. A method for producing a decorative sheet coating material using the adhesive composition described.