Curing agent composition for curing 2-methylene-1,3-dicarbonyl compound

Abstract

A curing agent composition is capable of curing a base resin containing a 2-methylene-1,3-dicarbonyl compound. The curing agent composition contains a specific 2-methylene-1,3-dicarbonyl compound and an initiator. A two-part mixing adhesive contains the curing agent composition and a base resin containing another specific 2-methylene-1,3-dicarbonyl compound.

Claims

1. A two-part mixing adhesive kit, wherein: (i) a first part of the two-part mixing adhesive kit includes a curing agent composition comprising: (a) an initiator comprising at least one basic substance, and (b1) at least one first 2-methylene-1,3-dicarbonyl compound having a molecular weight of 180 or higher and 10,000 or lower, the first 2-methylene-1,3-dicarbonyl compound comprising at least one structural unit represented by formula (I), and (ii) a second part of the two-part mixing adhesive kit includes a base resin comprising (b2) at least one second 2-methylene-1,3-dicarbonyl compound, the second 2-methylene-1,3-dicarbonyl compound comprising at least one structural unit represented by formula (I), and wherein formula (I) is ##STR00015##

2. The two-part mixing adhesive kit according to claim 1, wherein the component (a) has a pK.sub.a of 8.0 or higher.

3. The two-part mixing adhesive kit according to claim 1, wherein the component (a) is an amine compound.

4. The two-part mixing adhesive kit according to claim 1, wherein the component (a) is a tertiary amine compound.

5. The two-part mixing adhesive kit according to claim 1, wherein the component (a) is at least one tertiary amine compound represented by the formula NRRR, wherein R and R are each, independently, a methyl group or an ethyl group, and R is a monovalent hydrocarbon group having two or more carbon atoms.

6. The two-part mixing adhesive kit according to claim 1, wherein the curing agent composition has a viscosity of 1,000 Pa.Math.s or lower upon being maintained at 25 C. for 12 hours.

7. The two-part mixing adhesive kit according to claim 1, wherein the component (b2) comprises at least one 2-methylene-1,3-dicarbonyl compound that is different from any 2-methylene-1,3-dicarbonyl compound in the component (b1).

8. A method for curing a base resin, comprising: bringing the base resin into contact with a curing agent composition, wherein the curing agent composition comprises: (a) an initiator comprising at least one basic substance, and (b1) at least one first 2-methylene-1,3-dicarbonyl compound having a molecular weight of 180 or higher and 10,000 or lower, the first 2-methylene-1,3-dicarbonyl compound comprising at least one structural unit represented by formula (I), wherein the base resin comprises (b2) at least one second 2-methylene-1,3-dicarbonyl compound, the second 2-methylene-1,3-dicarbonyl compound comprising at least one structural unit represented by formula (I), and wherein formula (i) is ##STR00016##

9. The method according to claim 8, wherein the component (a) has a pK.sub.a of 8.0 or higher.

10. The method according to claim 8, wherein the component (a) is an amine compound.

11. The method according to claim 8, wherein the component (a) is a tertiary amine compound.

12. The method according to claim 8, wherein the component (a) is at least one tertiary amine compound represented by the formula NRRR, wherein R and R are each, independently, a methyl group or an ethyl group, and R is a monovalent hydrocarbon group having two or more carbon atoms.

13. The method according to claim 8, wherein the curing agent composition has a viscosity of 1,000 Pa.Math.s or lower upon being maintained at 25 C. for 12 hours.

14. The method according to claim 8, wherein the component (b2) comprises at least one 2-methylene-1,3-dicarbonyl compound that is different from any 2-methylene-1,3-dicarbonyl compound in the component (b1).

Description

EXAMPLES

(1) Examples and comparative examples of the present invention will be described below. The present invention is not limited to the following Examples and Comparative Examples. In the following Examples and Comparative Examples, the amounts of components contained in compositions and adhesives are indicated in terms of mass (unit: g).

(2) [Calculating Vapor Pressures]

(3) Vapor pressures at various temperatures were calculated for embodiments of the 2-methylene-1,3-dicarbonyl compound used in the present invention, using HSPiP (5th Edition 5.0.04, Y-MB method). Table 1 shows the vapor pressures (unit: mmHg) at various temperatures for diethyl methylene malonate (DEIM), ethyl propyl methylene malonate (EPrMM), dipropyl methylene malonate (DPrMVM), butyl pentyl methylene malonate (BPeMM), dipentyl methylene malonate (DPeMM), dihexyl methylene malonate (DH MM), and dicyclohexyl methylene malonate (DCHIMM).

(4) TABLE-US-00001 TABLE 1 Molecular Temperature [ C.] Sample Weight 25 50 80 100 120 150 DEMM 172.2 0.0648 0.5542 4.2095 12.7600 33.3400 113.1 EPrMM 186.2 0.0217 0.2205 1.9453 6.3700 17.7500 65.0800 DPrMM 200.2 0.0077 0.0928 0.9473 3.3444 9.9167 39.2200 BPeMM 242.3 0.0002 0.0039 0.0705 0.3343 1.2634 6.6901 DPeMM 256.3 0.0000 0.0010 0.0243 0.1307 0.5482 3.2830 DHMM 284.4 0.0000 0.0001 0.0024 0.0174 0.0925 0.7308 DCHMM 280.4 0.0000 0.0000 0.0009 0.0064 0.0340 0.2722
[Preparing Curing Agent Compositions]

(5) The raw materials for the curing agent compositions used in the Examples and Comparative Examples below are as follows.

Initiator (Component (a))

(6) DEBA Diethylbenzylamine (Wako Pure Chemical Industries, Ltd., Molecular weight: 165.3)

(7) In the Examples and Comparative Examples below, the following 2-methylene-1,3-dicarbonyl compounds were used singly or in combination of two compounds.

2-Methylene-1,3-dicarbonyl compounds (Component (b1))

(8) DEMM (manufactured by Sirrus Inc., molecular weight: 172.2)

(9) DHIMM (manufactured by Sirrus Inc., molecular weight: 284.4)

(10) DCHMM (manufactured by Sirrus Inc., molecular weight: 280.4)

(11) The chemical structures of these compounds are shown in Table 2 below.

(12) TABLE-US-00002 TABLE 2 DEMM Diethyl methylene malonate DCHMM Dicyclohexyl methylene malonate DHMM Dihexyl methylene malonate

(13) The aforementioned components (a) and (b1) were placed in a borosilicate glass screw tube bottle in the mass ratios shown in Table 3. The bottle was shaken vigorously for 3 minutes at room temperature (25 C.) to thoroughly mix the contents. The time elapsed from the completion of this mixing till the substance in the screw tube bottle practically lost fluidity accompanied by a clear release of heat (gel time) was measured at room temperature (25 C.). The results are shown in Table 3.

(14) Here, the expression practically loses fluidity refers to a state in which the substance that fills the screw tube bottle to about half its capacity is immobilized on the inner wall of the bottle and no obvious change in shape is observed under gravity for 10 seconds after the bottle is rapidly turned horizontal from a vertical position. If the substance has practically lost fluidity in this sense, its viscosity can be determined to be at least over 1,000 Pa.Math.s. By contrast, if clear fluidity is observed such as an instant deformation of the substance upon undergoing the procedure above, its viscosity can be determined to be at most 1,000 Pa.Math.s or lower.

(15) TABLE-US-00003 TABLE 3 Example Example Example Comparative 1 2 3 Example 1 Component (a) DEBA 0.04 0.04 0.04 0.06 Component DEMM 2.94 (b1) DHMM 2.96 1.48 DCHMM 2.96 1.48 Total 3.00 3.00 3.00 3.00 Gel time (min) >720 >720 >720 45
(Discussion on Results)

(16) The curing agent compositions in which an amine compound that has a high basicity (pK.sub.a value of 8.0 or higher) and, as a whole molecule, displays relatively high steric hindrance is combined with a component (b1) having relatively high steric hindrance near the reactive moiety showed low curing rates. Their viscosities were determined to have remained lower than 1,000 Pa.Math.s even 12 hours after preparation when they were kept at 25 C., based on the observation that the curing agent compositions were clearly fluid (Examples 1 to 3).

(17) By contrast, the curing agent composition in which the same amine compound was combined with a component (b1) that has relatively small steric hindrance near the reactive moiety showed an excessively high curing rate. Its viscosity was determined to have reached 1,000 Pa.Math.s in less than 12 hours after preparation when it was kept at 25 C., based on the observation that the curing agent composition practically lost fluidity (Comparative Example 1).

(18) [Base Resin]

(19) In the following Examples and Comparative Examples, the 2-methylene-1,3-dicarbonyl compound (component (b2)) was used as a base resin, which was cured using the curing agent composition of Example 1 above. For component (b2), the compound used as component (b1) in Comparative Example 1 above was used by itself.

(20) The curing characteristics of a two-part mixing adhesive consisting of the curing agent composition of Example 1 above and the component (b2) described above, serving as the base resin, were evaluated by measuring its gel time at room temperature (25 C.) in the same manner as in the evaluation of the curing characteristics for the curing agent compositions described above.

(21) The amounts of the curing agent composition and the base resin used (unit: g), as well as the measured gel time, are shown in Table 4.

(22) TABLE-US-00004 TABLE 4 Example 4 Component (b2) DEMM 1.50 Curing agent Example 1 1.50 Total 3.00 Gel time (min) 105

Discussion on Results

(23) The two-part mixing adhesive comprising a base resin in the form of a component (b2) having relatively small steric hindrance near the reactive moiety showed a moderate curing rate. When the mixture obtained by mixing the curing agent composition with the base resin was kept at 25 C., its viscosity was determined to have remained lower than 1,000 Pa.Math.s 60 minutes after the mixing, based on the observation that the mixture was clearly fluid, and its viscosity was determined to have reached 1,000 Pa.Math.s in less than 120 minutes, based on the observation that the mixture practically lost fluidity (Example 4).

Example 5

(24) The same operating procedures as in Example 4 will be performed, except that the mass of the curing agent composition is changed to 1.51 g and the mass of component (b2) is changed to 1.49 g. The gel time will be almost the same as in Example 4.

Example 6

(25) The same operating procedures as in Example 4 will be performed, except that the mass of the curing agent composition is changed to 1.49 g and the mass of component (b2) is changed to 1.51 g. The gel time will be almost the same as in Example 4.

Comparative Examples 2 to 4

(26) A mixture of 1.48 parts by mass of DHMM and 1.50 parts by mass of DEMM will be prepared and used to prepare the following three compositions: Comparative Example 2: Composition obtained by adding 0.02 g of DEBA to 2.98 g of the mixture above Comparative Example 3: Composition obtained by adding 0.03 g of DEBA to 2.97 g of the mixture above Comparative Example 4: Composition obtained by adding 0.01 g of DEBA to 2.99 g of the mixture above.

(27) For each of the three compositions above, the gel time at room temperature (25 C.) will be measured in the same manner as in the evaluation of the curing characteristics for the curing agent compositions described above. In Comparative Example 3, the gel time of the composition will be significantly shorter than that of Comparative Example 2, and in Comparative Example 4, the gel time of the composition will be significantly longer than that of Comparative Example 2.

Discussion on Results

(28) Compositions obtained by adding an amine compound to a mixture of component (b1) and component (b2) will show significant variation in curing time, due to variations in the amounts mixed that are about as small as within the tolerance range of a measuring instrument. In contrast, the curing time of the two-part mixing adhesive of the present invention will be hardly affected, even if the amounts of the curing agent composition and the base resin mixed vary to about the same extent. Therefore, the two-part mixing adhesive of the present invention is conducive to consistent performance of adhesion and other operations.

INDUSTRIAL APPLICABILITY

(29) The curing agent composition of the present invention remains liquid without curing for a long time, but when this composition is mixed with a base resin comprising a 2-methylene-1,3-dicarbonyl compound, the resulting mixture cures in a suitable curing time even at relatively low temperatures such as room temperature. The cured product has no liquid components that separate without becoming incorporated into the polymerization system. In other words, the curing agent composition of the present invention, when combined with the base resin described above, provides a two-part mixing adhesive that can be conveniently and effectively used as an adhesive or sealing agent, and, therefore, is extremely useful. In addition, such a two-part mixing adhesive allows the mixing ratio of the curing agent composition and the base resin to be set at any desired level, for example, 1:1 by volume, which enables achievement of the desired curability and the desired properties of the cured product, even if the actual ratio of the curing agent composition and the base resin differs slightly from the desired ratio. Furthermore, the cured product contains no liquid components that separate without being incorporated into the polymerization system, thereby preventing outgassing and bleeding.