Curable Composition

Abstract

A curable composition capable of securing a waiting time after curing starts, and efficiently controlling the relevant waiting time is provided. The curable composition also controls a curing rate after the waiting time to suit the application. A battery module, a battery pack or an automobile comprising a cured product of the curable composition is also provided.

Claims

1. A curable composition comprising: a polyol, a reaction inhibitor, a catalyst and a filler, wherein a required time (Vt2) for the curable composition to double its initial viscosity is 15 minutes or more, wherein the initial viscosity is measured with a Brookfield HB type viscometer at a temperature of 25° C. under conditions of a torque of 90% and a shear rate of 100 rpm, and wherein the initial viscosity is measured at a curing start point.

2. The curable composition according to claim 1, wherein a difference (H.sub.ti−V.sub.t2) between the required time (V.sub.t2) and a Shore A hardness confirmation time (H.sub.ti) is in a range of 25 minutes to 300 minutes.

3. The curable composition according to claim 1, wherein an initial load value (Li) is in a range of 10 to 35 kgf.

4. The curable composition according to claim 3, wherein a load value change rate by the following equation 1 is in a range of 1 to 2:
Load value change rate=Lf/Li  [Equation 1] wherein, Li is the initial load value, and Lf is a load value at a time of 30 minutes after the curing start point.

5. The curable composition according to claim 1, wherein the reaction inhibitor comprises one or more reaction-inhibitory functional groups selected from the group consisting of a mercapto group, an amino group and a phenolic hydroxyl group.

6. The curable composition according to claim 5, wherein the reaction inhibitor has a functional value by the following equation 2 in a range of 0.001 to 0.02:
FV=F/M  [Equation 2] wherein, FV is the functional value, F is a number of reaction-inhibitory functional groups in the reaction inhibitor, and M is a molar mass of the reaction inhibitor.

7. The curable composition according to claim 1, wherein the reaction inhibitor is present such that R1 in the following equation 3 is in a range of 2 to 30:
R1=(W1×O/M)−(FV×W2)  [Equation 3] wherein, O is a hydroxyl value of the polyol, M is a weight average molecular weight of the polyol, FV is a reaction-inhibitory functional value of the reaction inhibitor, W1 is a weight ratio of the polyol to the reaction inhibitor, and W2 is a weight ratio of the reaction inhibitor to the polyol.

8. The curable composition according to claim 1, wherein a weight ratio (IW/CW) of the reaction inhibitor (IW) to the catalyst (CW) is in a range of 1.3 to 4.

9. The curable composition according to claim 1, wherein the filler is included in an amount of 70 to 95 parts by weight based on 100 parts by weight of the curable composition.

10. The curable composition according to claim 1, further comprising an isocyanate compound.

11. The curable composition according to claim 10, wherein the isocyanate compound has an isocyanate value by the following equation 4 in a range of 0.001 to 0.1:
NCOV=NCO/MN  [Equation 4] wherein, NCOV is the isocyanate value, NCO is a number (molar number) of isocyanate groups in the isocyanate compound, and MN is a molar mass of the isocyanate compound.

12. The curable composition according to claim 10, wherein the isocyanate compound is present such that R2 in the following equation 5 is in a range of 10 to 150:
R2=(W1×O/M)/(NCOV×W3)  [Equation 5] wherein, O is a hydroxyl value of the polyol, NCOV is an isocyanate value of the isocyanate compound, W1 is a weight ratio of the polyol to the isocyanate compound, and W3 is a weight ratio of the isocyanate compound to the polyol.

13. The curable composition according to claim 10, wherein the isocyanate compound is present such that R3 in the following equation 6 is in a range of 50 to 500:
R3=(FV×W2)/(NCOV×W3)  [Equation 6] wherein, FV is a reaction-inhibitory functional value of the reaction inhibitor, NCOV is an isocyanate value of the isocyanate compound, W2 is a weight ratio of the reaction inhibitor to the isocyanate compound, and W3 is a weight ratio of the isocyanate compound to the reaction inhibitor.

14. A battery module comprising: a module case having an internal space; a plurality of battery cells in the internal space of the module case; and a resin layer comprising a cured product of the curable composition of claim 1, wherein the resin layer in the internal space is in contact with the plurality of battery cells and the module case.

15. A battery pack comprising two or more battery modules of claim 14 that are electrically connected to each other.

Description

DESCRIPTION OF DRAWINGS

[0174] FIG. 1 shows an exemplary mixer applicable to the present application.

[0175] FIG. 2 shows an exemplary module case applicable to the present application.

[0176] FIG. 3 schematically shows a form that battery cells are accommodated in a module case.

MODE FOR INVENTION

[0177] Hereinafter, the present application is specifically described through Examples and Comparative Examples, but the scope of the present application is not limited by the following Examples.

[0178] 1. Viscosity

[0179] The viscosity of the curable composition (main agent composition, curing agent composition, or mixture thereof) was measured using a Brookfield HB type viscometer. When measuring the viscosity, the temperature was maintained at about 25° C. Using the viscometer, the viscosity of the curable composition was measured over time under conditions of a torque of about 90% and a shear rate of about 100 rpm.

[0180] 2. Hardness

[0181] The hardness of the curable composition was measured using an Asker durometer according to ASTM D 2240 standard. The hardness was measured over time in the thickness direction in a state that the curable composition was maintained in the form of a film having a thickness of about 4 mm and the temperature was maintained at about 25° C. The initial hardness was measured by applying a load of 1 Kg or more (about 1.5 Kg) to the surface of the sample in the form of a film, and the hardness (Shore A hardness) was evaluated by confirming the measured value stabilized after 15 seconds.

[0182] 3. Load Value (Li, Lf)

[0183] The load value (kgf) of the curable composition was measured using a measuring apparatus (1) in which two cartridges (2a, 2b) and one static mixer (5) were connected as shown in FIG. 1.

[0184] In the measuring apparatus (1), as the cartridges (2a, 2b), cartridges (Sulzer, AB050-01-10-01) having a circular injection part with a diameter of 18 mm and a circular discharge part (4, 4a, 4b) with a diameter of 3 mm, and having the height of the cartridges (2a, 2b) of 100 mm and the inner volume of 25 ml was used. In the measuring apparatus (1), as the static mixer (5), a mixer (5) (Sulzer, MBH-06-16T) having a circular discharge part (7) with a diameter of 2 mm, being a stepped type, and having 16 elements was used. In the measuring apparatus, as the pressurization means (3, 3a, 3b), a TA (texture analyzer) was used.

[0185] The main agent composition of the two-component curable composition was filled in any one of the two cartridges (2a, 2b), the curing agent composition was filled in the other cartridge, and then a constant force was applied thereto with the pressing means (3, 3a, 3b), whereby the load values (Li, Lf) were measured while the main agent and curing agent compositions were mixed in the static mixer (5) via the first discharge parts (4a, 4b), respectively, and then discharged to the second discharge part (7).

[0186] The main agent and curing agent compositions are loaded into the two cartridges (2a, 2b), respectively, and then pressurized at a constant speed of 1 mm/s or so with TAs (texture analyzers) (3a, 3b), whereby the compositions are mixed inside the static mixer (5), and then the force applied to the pressurizing means is measured from the first discharge, where the load value Li is the maximum value at the point where the force becomes the maximum value.

[0187] The load value Lf was measured in a manner similar to the load value Li. That is, the main agent and curing agent compositions are loaded into the two cartridges (2a, 2b), respectively, and then pressurized at a constant speed of 1 mm/s or so with TAs (texture analyzers) (3a, 3b), whereby the compositions are mixed inside the static mixer (5), and then the force applied to the pressurizing means is measured from the first discharge, where the load value Lf is the maximum value at the point where the force becomes the maximum value. However, upon measuring Li, the pressurization was performed with the pressurizing means without interruption until the maximum value was measured, but upon measuring Lf, the pressurization by the pressurizing means was stopped at the time when the main agent and curing agent compositions were mixed inside the mixer (5), the curing reaction was performed inside the mixer (5) for 30 minutes or so, and then the maximum value was measured while performing the pressurization again at a constant speed (1 mm/s), where the maximum value was taken as Lf.

[0188] The time point when the pressurization was stopped upon the measurement of Lf was a time point when the amount of the main agent composition and the curing agent composition injected into the mixer (5) became 95% or so of the capacity (volume) of the mixer. The mixture was pressurized again at a constant speed of 1 mm/s with the pressurizing means after the 30 minutes, and the force applied to the pressurizing means began to be measured from the first discharge, where the maximum value at the point where the force becomes the maximum value was set as the load value (Lf).

[0189] The maximum value is the first confirmed maximum value. That is, when the force applied during pressurization with the pressurizing means is measured as described above, the force increases and then decreases, or increases and then is maintained at a certain level without increasing any more, where the maximum value is the maximum value before the decrease or the maximum value maintained at a certain level.

[0190] 4. Weight Average Molecular Weight Measurement

[0191] The weight average molecular weight of the polyol was measured by GPC (gel permeation chromatograph). Specifically, it was measured according to the following procedure.

[0192] (1) Into a 5 mL vial, an analyte (polyol) is put and diluted in THF (tetrahydrofuran) to be a concentration of about 1 mg/mL or so.

[0193] (2) A standard sample for calibration and a sample to be analyzed are filtered through a syringe filter (pore size: 0.45 μm).

[0194] (3) The GPC analysis is performed after injecting the filtered standard sample and analytical sample into the GPC apparatus.

[0195] As the analytical program, ChemStation from Agilent Technologies was used, and the elution time of the sample was compared with the calibration curve to calculate the weight average molecular weight (Mw). The measurement conditions of GPC are as follows.

[0196] <GPC Measurement Conditions>

[0197] Instrument: 1200 series from Agilent Technologies

[0198] Column: using PLgel mixed B from Polymer laboratories

[0199] Solvent: THF

[0200] Column temperature: 35° C.

[0201] Sample concentration: 1 mg/mL, 200 μL injection

[0202] Standard samples: Polystyrene (Mp: 3900000, 723000, 316500, 52200, 31400, 7200, 3940, 485)

Example 1

[0203] The curable composition was prepared in a two-component type. That is, a polyol (main agent resin), a reaction inhibitor, a catalyst and a filler were mixed to prepare a main agent composition, and an isocyanate compound and a filler were mixed to prepare a curing agent composition.

[0204] As the main agent resin, caprolactone polyol represented by the following formula 4 was used. The polyol had a weight average molecular weight of about 400 g/mol or so, and a hydroxyl value (OH value) of about 280 mgKOH/g or so. The hydroxyl value is evaluated according to a standard test method (ASTM E 1899-08).

##STR00002##

[0205] In Formula 4, m is a number in a range of 1 to 3, R.sub.1 and R.sub.2 are each an alkylene having 4 carbon atoms, and Y is a 1,4-butanediol unit.

[0206] As the reaction inhibitor, 1-dodecanethiol (molar mass: about 202.4 g/mol) was used, as the catalyst, dibutyltin dilaurate (DBTDL) was used, and as the curing agent, HDI (hexamethylene diisocyanate, molar mass about 168.2 g/mol) was used.

[0207] As the filler, alumina was used, where a filler mixture, in which a first filler having a D50 particle diameter of about 40 μm, a second filler having a D50 particle diameter of about 20 μm, and a third filler having a D50 particle diameter of about 2 μm were mixed in a weight ratio of 4:3:3 (first filler:second filler:third filler), was used.

[0208] The main agent composition was prepared by mixing the caprolactone polyol, the reaction inhibitor, the catalyst and the filler in a weight ratio of 9.98:0.12:0.040:89.9 (polyol:reaction inhibitor:catalyst:filler), and the curing agent composition was prepared by mixing the HDI and the filler in a weight ratio of 10:90 (HDI:filler). Here, the weight ratio (polyol:HDI) of the polyol in the main agent composition to the HDI in the curing agent composition was 1:1 or so.

[0209] The mixing upon the preparation of the main agent composition and the curing agent composition was performed with a planetary mixer.

Example 2

[0210] The compositions were each prepared in the same manner as in Example 1, except that the weight ratio (polyol:reaction inhibitor:catalyst:filler) of the caprolactone polyol, the reaction inhibitor, the catalyst and the filler was 9.98:0.15:0.070:89.8 upon preparing the main agent composition, the weight ratio (HDI:filler) of the HDI and the filler was 10:90 upon preparing the curing agent composition, and the weight ratio (polyol:HDI) of the polyol in the main agent composition and the HDI in the curing agent composition was 1:1.

Example 3

[0211] The compositions were each prepared in the same manner as in Example 1, except that the weight ratio (polyol:reaction inhibitor:catalyst:filler) of the caprolactone polyol, the reaction inhibitor, the catalyst and the filler was 9.98:0.12:0.070:89.8 upon preparing the main agent composition, the weight ratio (HDI:filler) of the HDI and the filler was 10:90 upon preparing the curing agent composition, and the weight ratio (polyol:HDI) of the polyol in the main agent composition and the HDI in the curing agent composition was 1:1.

Example 4

[0212] The compositions were each prepared in the same manner as in Example 1, except that the weight ratio (polyol:reaction inhibitor:catalyst:filler) of the caprolactone polyol, the reaction inhibitor, the catalyst and the filler was 9.97:0.25:0.090:89.7 upon preparing the main agent composition, the weight ratio (HDI:filler) of the HDI and the filler was 10:90 upon preparing the curing agent composition, and the weight ratio (polyol:HDI) of the polyol in the main agent composition and the HDI in the curing agent composition was 1:1.

Example 5

[0213] As the reaction inhibitor, 3-mercaptopropyltrimethoxysilane (molar mass: about 196.4 g/mol) was used instead of 1-dodecanethiol (molar mass: about 202.4 g/mol), and other materials were used in the same manner as in Example 1.

[0214] The compositions were each prepared in the same manner as in Example 1, except that the weight ratio (polyol:reaction inhibitor:catalyst:filler) of the caprolactone polyol, the reaction inhibitor, the catalyst and the filler was 9.97:0.15:0.070:89.8 upon preparing the main agent composition, the weight ratio (HDI:filler) of the HDI and the filler was 10:90 upon preparing the curing agent composition, and the weight ratio (polyol:HDI) of the polyol in the main agent composition and the HDI in the curing agent composition was 1:1.

Comparative Example 1

[0215] The compositions were each prepared in the same manner as in Example 1, except that the weight ratio (polyol:catalyst:filler) of the caprolactone polyol, the catalyst and the filler was 9.99:0.090:89.9 upon preparing the main agent composition, the weight ratio (HDI:filler) of the HDI and the filler was 10:90 upon preparing the curing agent composition, and the weight ratio (polyol:HDI) of the polyol in the main agent composition and the HDI in the curing agent composition was 1:1.

[0216] The physical properties measured for Examples and Comparative Examples above were summarized and described in Table 1 below.

TABLE-US-00001 TABLE 1 Vt.sub.2 Ht.sub.i Ht.sub.40 Ht.sub.90 L.sub.i L.sub.f Example 1 45.7 110 115 180 27.3 29.7 Example 2 28 60 65 110 21.5 24.9 Example 3 21.5 50 55 90 28.8 40.4 Example 4 45.7 85 90 140 27.3 29.7 Example 5 16.2 45 50 90 27.2 45.2 Comparative Example 1 3.8 30 40 80 27.7 — *Vt.sub.2: Elapsed time from the time point of mixing the main agent and curing agent compositions until the viscosity of the mixed composition of the main agent and curing agent compositions becomes twice as high as that at the mixing time point (unit: minute) *Ht.sub.i: Required time from the time point of mixing the main agent and curing agent compositions to the start of measurement of Shore A hardness of the mixed composition of the main agent and curing agent compositions (unit: minute) *Ht.sub.40: Required time from the time point of mixing the main agent and curing agent compositions to the Shore A hardness of the mixed composition of the main agent and curing agent compositions reaching 40 (unit: minute) *Ht.sub.90: Required time from the time point of mixing the main agent and curing agent compositions to the Shore A hardness of the mixed composition of the main agent and curing agent compositions reaching 90 (unit: minute) *L.sub.i: Load value Li measured for the mixture of the main agent and curing agent compositions (unit: kgf) *L.sub.f: Load value Lf measured for the mixture of the main agent and curing agent compositions (unit: kgf)

[0217] It can be confirmed through the results of Table 1 that an appropriate waiting time can be secured by the curable composition of the present application. That is, it has confirmed that the V.sub.t2 has been measured longer in the presence of the reaction inhibitor than in its absence, and under the same other conditions, the higher the ratio of the amount of reaction inhibitor based on the catalyst amount, the longer the waiting time has been secured, and under the same other conditions, the lower the functional value of the reaction inhibitor, the longer the waiting time has been secured.

[0218] In addition, it has been confirmed from H.sub.ti, H.sub.t40 or H.sub.t90 that when other conditions are the same, the case where the content of the catalyst increases, the case where the ratio of the amount of the reaction inhibitor based on the amount of catalyst increases and/or the case where the functional value of the reaction inhibitor increases tend to make the curing rate faster after the waiting time.

[0219] Furthermore, the curable compositions of Examples exhibited low load values (L.sub.i, L.sub.f).

[0220] On the other hand, in the case of the curable composition of Comparative Example, the waiting time was not properly secured, and an excessively large load value was exhibited.