JP4241427B2 - Crystalline polymer - Google Patents

Description

  The present invention relates to a crystalline polymer having a novel physical property and undergoing crystal transition in a solid state.

Trans-1,4-polybutadiene is well known as a crystalline polymer that reversibly crystallizes in the solid phase.
A crystalline polymer that generates a reversible crystal transition in a solid phase can be applied to a functional material such as a heat storage material or a PTC element by utilizing heat transfer and volume change phenomenon accompanying the crystal transition. (For example, Japanese Patent Application Laid-Open No. 2003-45704 by the present applicant (Patent Document 1).) The crystal transition temperature at the time of temperature rise measured by DSC is a heat absorption temperature when used as a heat storage material or a PTC. And the crystal transition enthalpy affects the magnitude of the function such as the amount of heat storage.

  For example, in a report by Finter et al. (Makromol. Chem. Vol. 182 p1859-1874 (1981)) (Non-patent Document 1), the microstructure of the butadiene unit is 100% transformer, the crystal transition temperature is 83 ° C., A trans-1,4-polybutadiene having a crystal transition heat value change of 7.79 kJ / mol (140 J / g) is disclosed.

  Also, a report by Bautz et al. (Colloid and Polymer Scienece Vol.259 No.7 P714-723 (1981)) (Non-patent Document 2) includes a crystal transition temperature of 68 ° C. (341 K) and a crystal transition heat of 98 J / g. Of trans-1,4 polybutadiene is described.

  Japanese Patent Application Laid-Open No. 2000-230103 (Patent Document 2) by the present applicant discloses a mixture of trans-1,4-polybutadiene and a thermoplastic resin as main components and application to a heat storage material.

Similarly, Japanese Patent Application Laid-Open No. 2001-81135 (Patent Document 3) by the present applicant discloses trans-1,4-polybutadiene having a specific structure and physical properties and showing a reversible phase transition.
However, in the above prior art, since the crystal transition temperature is limited to 68 ° C. or higher, for example, when it is used as a heat storage material, the required heat source temperature is increased, and improvement has been demanded.

In addition, a report by Bermudez et al. (European Polymer Journal Vol.8 p575-583 (1972)) (Non-Patent Document 3) includes a crystal transition temperature of 50 to 52 ° C. and a crystal transition calorie change of 48 to 57.2 J / g. Of trans-1,4 polybutadiene is described.
However, in the above prior art, the change in crystal transition enthalpy is remarkably reduced. For example, when it is used as a heat storage material, the heat storage performance itself is lowered and improvement is required.

In addition, a report by Antipov et al. (Macromol. Chem. Phys. Vol. 202, p82-89 (2001)) (non-patent document 4) includes 1,4-trans bond and 1,2-vinyl bond of polybutadiene. A crystalline polybutadiene having a reduced crystal transition temperature (minimum of 40 ° C.) by controlling the ratio of the above and controlling the trans bond ratio to 98% or less is disclosed. (However, the quantified phase transition enthalpy change amount is not disclosed.)
However, in the above prior art, since the melting point decreases with a decrease in the crystal transition temperature, the function expression temperature and the polymer flow temperature become close, and the feature as a solid heat storage material that does not require sealing is negated, and the heat storage material As the environmental temperature that can be used as a restriction is also generated, improvement has been demanded.

  Japanese Patent Application Laid-Open No. 9-268208 (Patent Document 4) by the present applicant describes a trans-1,4 polybutadiene having a trans bond content of 95 mol% or more, a weight average molecular weight of 1 million or less, and ΔHtr of 70 J / g or more. And a heat storage material using the same, and in particular, a polymer having a number average molecular weight of 800,000 having a relatively high phase transition heat of 92 J / g at a crystal transition temperature of 60 ° C. is disclosed.

  However, the above prior art requires improvement because the crystal transition temperature is high, or if the crystal transition temperature is low, the molecular weight is as high as 800,000, so the workability is low and improvement is required.

  That is, in the prior art, there are cases where various properties such as calorific value, crystal transition temperature, melting point, moldability and the like accompanying crystal transition cannot be satisfied depending on the application, and improvement has been demanded.

Natta et al. In US Pat. No. 3,407,185 (Patent Document 5) contains 71.3 mol% of butadiene units at the maximum, has long butadiene chains and ethylene units alternately, and has a microstructure of butadiene units of 95 at maximum. A crystalline polymer comprising a butadiene ethylene copolymer containing 3% trans bonds is disclosed.
However, the polymer according to the above technique has few crystal components derived from trans-1,4-polybutadiene exhibiting crystal transition characteristics, and when used as a heat storage material, the characteristics are not satisfactory, and improvement has been desired. .

Japanese Patent Laid-Open No. 2003-45704 JP 2000-230103 A JP 2001-81135 A Japanese Patent Laid-Open No. 9-268208 USP 3407185 Makromol.Chem. Vol.182 p1859-1874 (1981) Colloid and Polymer Scienece Vol.259 No.7 P714-723 (1981) European Polymer Journal Vol.8 p575-583 (1972) Macromol. Chem. Phys. Vol.202, p82-89 (2001)

The crystalline polymer according to the prior art has a high crystal transition temperature when the phase transition heat quantity is sufficiently high, and the temperature of function expression is limited. On the other hand, when the crystalline transition temperature is low with a crystalline polymer, the phase transition heat amount is significantly decreased, the function of heat storage, etc. is inferior, the molecular weight is high and the processability is poor, or the melting point is low and the usage conditions are limited. is there. For this reason, improvement in physical properties has been demanded on either side.
An object of the present invention is to provide a polymer that improves the balance of the three requirements of low phase transition temperature, high phase transition heat, and high processability (low molecular weight), and further maintains a high melting point.

The present invention is a copolymer of butadiene and ethylene , (A) the weight average molecular weight measured by GPC is 600,000 or less,
(B) shows a reversible crystal transition phenomenon in a solid state, a crystal transition temperature (Ttr) at a temperature rise of 67 to 40 ° C., and the following formula (1)
ΔHtr> 2Ttr-40 (1)
(However, ΔHtr is the total amount (J / g) of the endothermic amount associated with the crystal transition per unit polymer amount, and Ttr is the temperature indicating the maximum value of the endothermic peak associated with the crystal transition when the temperature is raised at 10 ° C./min (° All are values measured with a differential scanning calorimeter.)
Satisfied,
(C) Melting point (Tm) is 120-140 ° C ,
(D) The microstructure of the butadiene unit has a trans-1,4 structure content of 97 mol% or more,
(E) It is related with the crystalline polymer characterized by the ratio of a butadiene unit and an ethylene unit being 93: 7-70: 30 .

  The present invention provides a novel crystalline polymer that causes a solid phase transition phenomenon, is easy to mold, and has a large heat transfer amount due to crystal transition at a low crystal transition temperature.

The crystalline polymer that crystallizes in the solid phase of the present invention is:
The weight average molecular weight is 600,000 or less, preferably 500,000 or less, particularly preferably 100,000 to 400,000.
The crystal transition temperature (Ttr) is 40 to 67 ° C., preferably 40 to 65 ° C., particularly preferably 55 to 65 ° C., and
The following formula (1)
ΔHtr> 2Ttr-40. . . . . (1)
Preferably ΔHtr> 2Ttr−35
(However, ΔHtr is the total amount of the endotherm per unit polymer amount (J / g) associated with the crystal transition, and Ttr is the temperature (° C.) indicating the maximum endothermic peak associated with the crystal transition when the temperature is raised at 10 ° C./min. These are values measured with a differential scanning calorimeter.
Satisfied.

  Specific examples of the crystalline polymer include trans-1,4-polybutadiene, a copolymer of butadiene and olefin, and the like.

  The microstructure of the butadiene unit has a trans-1,4 bond content calculated from an IR spectrum, or a spectrum such as 1H-NMR, 13C-NMR, etc., and the trans-1,4 structure content is 97 mol% or more, preferably 98% or more.

  Examples of the olefin in the case of a copolymer of butadiene and olefin include ethylene, propylene, and butene. Of these, ethylene is preferable.

  When the crystalline polymer is a copolymer of butadiene and olefin, the ratio of the butadiene unit to the olefin unit is preferably 93: 7 to 70:30, and particularly preferably 86:14 to 75:25.

  As the characteristics of the crystalline polymer of the present invention, the endothermic amount (crystal transition heat amount) ΔHtr (J / g) accompanying crystal transition is preferably 40 to 160, particularly preferably 60 to 150.

  The melting point (Tm) of the crystalline polymer is preferably 100 ° C. or higher, and particularly preferably 120 to 140 ° C.

  The heat of fusion (ΔHf) (J / g) of the crystalline polymer is preferably 35-60, and particularly preferably 40-55.

  The weight average molecular weight (Mw) is 600,000 or less, preferably 30,000 to 400,000. Here, the weight average molecular weight is obtained by gel permeation chromatography (GPC) using styrene as a standard substance and o-dichlorobenzene as a solvent.

  The number average molecular weight (Mn) is 200,000 or less, preferably 10,000 to 100,000.

  The molecular weight distribution (Mw / Mn) is preferably from 2 to 40, particularly preferably from 3 to 15.

  The crystalline polymer of the present invention can be molded into pellets, thin plates, lamination with metal plates, hollow fibers, structures, cast films and the like. It is used in contact with a heat medium as pellets or molded bodies. Moreover, you may mix and use with the other polymer which does not show a phase transition phenomenon.

  The trans-1,4-polybutadiene of the present invention can be produced by polymerization using a catalyst comprising (A) a vanadium compound and (B) an alkylaluminum chloride.

(A) Vanadium compound catalysts include vanadium compounds such as vanadium triacetylacetonate, vanadium trichloride THF complex, vanadium oxytrichloride, vanadium naphthenate, and vanadium oxyalkoxide. Among these, vanadium oxytrichloride (VOCl ₃ ) is preferable.

  Examples of (B) alkylaluminum chloride include dimethylaluminum chloride, diethylaluminum chloride, diisobutylaluminum chloride, methylaluminum dichloride, ethylaluminum sesquichloride, and ethylaluminum dichloride. Of these, diethylaluminum chloride (DEAC) and ethylaluminum sesquichloride (EASC) are preferable.

  The ratio of the component (A) to the component (B) is preferably 1: 300 to 10: 1 in terms of a molar ratio.

As the polymerization method, solution polymerization performed using a solvent, gas phase polymerization using a catalyst supported on a carrier, bulk polymerization using a butadiene monomer as a medium, and the like can be employed. Examples of the solvent that can be used in the solution polymerization include aliphatic hydrocarbons such as pentane, hexane, heptane, and cyclohexane, aromatic hydrocarbons such as benzene, toluene, and xylene, and halogenated hydrocarbons such as chloroform, methylene chloride, dichloroethane, and chlorobenzene. And mineral oil.
In the case of copolymerization with an α-olefin, the α-olefin may be added only at the initial stage of polymerization or continuously supplied.

  In each polymerization method, the polymerization time is usually 1 minute to 12 hours, preferably 5 minutes to 2 hours, and the polymerization temperature is −10 to 60 ° C., preferably 0 to 40 ° C.

In the examples, “polymerization activity” is the yield (g) of polymer produced per 1 mmol of vanadium metal component of the catalyst containing vanadium oxytrichloride VOCl ₃ .

  The “weight average molecular weight” was determined as follows. By gel permeation chromatography (GPC) of Waters 150C type using styrene as a standard substance (using 2 ShodexHT-806M columns manufactured by Showa Denko and 1 ShodexHT-800P as a precolumn), solvent o-dichlorobenzene at a column temperature of 135 ° C. The standard polystyrene is measured under the same conditions, and a calibration curve is created and calibrated to obtain the GPC curve.

“Trans-1,4 bond content” and “olefin content” were calculated from the intensity ratio of each peak in the C ¹³ -NMR spectrum measured using EX-400 manufactured by JEOL.

  “Crystal phase transition point” and “crystal phase transition heat” were determined as follows. Using a differential scanning calorimeter (DSC) of SSC 5200 manufactured by Seiko Instruments Inc., a sample of about 5 mg placed in an aluminum sample pan and sealed was heated at 250 ° C. for 10 minutes in a nitrogen atmosphere. After melting, the temperature was lowered to −30 ° C. at −5 ° C./min for recrystallization. The temperature of this polymer was raised at 10 ° C./min, the temperature showing the maximum value of the endothermic peak accompanying the crystal transition was taken as the crystal transition temperature, and the total amount per unit polymer of the endotherm due to the crystal transition was taken as the crystal transition heat quantity. Further, the temperature showing the maximum value of the endothermic peak accompanying crystal melting was taken as the melting point, and the total amount per unit polymer of the endothermic quantity accompanying crystal melting was taken as the heat of fusion.

(Example 1) A small pressure polymerization apparatus having an internal volume of 15 ml was sufficiently purged with nitrogen, then 2 ml of toluene was added, and 0.05 mmol (0.05 M toluene solution) of diethylaluminum chloride (DEAC) was added as a co-catalyst. 0.4 MPa of ethylene was introduced and then 2 ml of butadiene (Bd) was added. After the inside of the reaction vessel was heated to 35 ° C., 0.01 mmol (0.01 M) of vanadium oxytrichloride (VOCl ₃ ) was added as a catalyst to initiate polymerization. The polymerization operation was performed in a closed system at 35 ° C. for 15 minutes in a nitrogen atmosphere. After stopping the polymerization reaction by injecting 6 ml of ethanol, the whole reaction solution was added to 15 ml of ethanol (100 ppm additive of anti-aging agent Irganox 1076) to precipitate and collect the polymer. The recovered polymer was washed with ethanol and dried.

(Example 2, Comparative Examples 1-10)
The same procedure as in Example 1 was performed except that the introduction pressure of ethylene was different.
1 and 2 show the C ¹³ NMR spectrum and DSC temperature rise curve of the polymer of Example 2. FIG.

(Example 3)
After DEAC introduction, ethylene of 0.4 MPa was introduced before butadiene introduction, and then ethylene was supplied so that the total pressure was constant during the polymerization, that is, ethylene was continuously supplied in an amount substantially corresponding to consumption. Except for this point, the same procedure as in Example 1 was performed.
(Examples 4 to 7)
As in Example 4, but the polymerization time was 5-60 min.

(Examples 8 to 10)
After DEAC was added, butadiene was added and heated to 35 ° C, and then 0.4 MPa of ethylene was introduced. Further, after adding VOCl ₃ , the ethylene partial pressure was increased to a predetermined pressure, and then ethylene was continuously supplied.

(Example 11, Comparative Examples 11-14)
The same operation as in Example 2 was performed except that the introduction pressure of ethylene was different.

(Example 12) A pressure polymerization apparatus having an internal volume of 2 L was sealed after a glass ampoule in which vanadium oxytrichloride (0.3 mmol / 0.2 M toluene solution) was sealed was fixedly installed. After sufficiently replacing the inside of the apparatus with nitrogen, 800 ml of toluene was introduced, 200 ml of butadiene was added, and then 1.5 mmol of diethylaluminum chloride (DEAC: 1 M toluene solution) as a cocatalyst was added. After the inside of the reaction vessel was heated to 35 ° C., ethylene having a gas phase partial pressure of 0.2 MPa was introduced and saturated with a solvent, and then polymerization was started by crushing the catalyst glass ampoule. The polymerization operation was carried out in a sealed manner in a nitrogen atmosphere at 35 ° C for 15 minutes.
After terminating the polymerization reaction by injecting 5 ml of ethanol, the entire reaction solution was added to 1 L of ethanol (additive of anti-aging agent Irganox 1076 700 ppm) to precipitate and collect the polymer. The recovered polymer was washed with ethanol and dried.

(Comparative Examples 15-18)
The same procedure as in Example 12 was performed except that the ethylene introduction pressure was different.

(Example 13)
The same procedure as in Comparative Example 18 was performed except that ethylaluminum sesquichloride (EASC) was used in place of DEAC as the organoaluminum promoter.

(Comparative Example 19)
The same procedure as in Example 13 was performed except that the ethylene introduction pressure was different.

The conditions and results of the above examples are summarized in Tables 1 to 3.

FIG. 1 shows the C ¹³ NMR spectrum of the polymer of Example 2 of the present invention. FIG. 2 shows a DSC temperature rise curve of the polymer of Example 2 of the present invention.

Claims (1)

A copolymer of butadiene and ethylene , (A) the weight average molecular weight measured by GPC is 600,000 or less,
(B) shows a reversible crystal transition phenomenon in a solid state, a crystal transition temperature (Ttr) at a temperature rise of 67 to 40 ° C., and the following formula (1)
ΔHtr> 2Ttr-40 (1)
(However, ΔHtr is the total amount (J / g) of the endothermic amount associated with the crystal transition per unit polymer amount, and Ttr is the temperature indicating the maximum value of the endothermic peak associated with the crystal transition when the temperature is raised at 10 ° C./min (° All are values measured with a differential scanning calorimeter.)
Satisfied,
(C) Melting point (Tm) is 120-140 ° C ,
(D) The microstructure of the butadiene unit has a trans-1,4 structure content of 97 mol% or more,
(E) A crystalline polymer, wherein the ratio of butadiene units to ethylene units is 93: 7 to 70:30 .

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