JP2879685B2 - Polycarbonate diol - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a polycarbonate diol compound.

[Prior Art] Polyurethane resins are used in many fields such as foams, adhesives, elastomers, fibers such as spandex and paints, and the main raw materials are polyisocyanates and polyols.

Polyols such as polypropylene glycol and polyether methylene glycol, polyester polyols derived from dihydric carboxylic acids such as adipic acid and polyhydric alcohols,
Polylactone polyols obtained by reacting lactones with alcohols and the like are used, and are used for various purposes according to the required performance.

However, since the polyether polyol has an ether bond, a urethane resin produced using the polyether polyol has a disadvantage that heat resistance and weather resistance are poor.

On the other hand, since polyester polyols and polylactone polyols have ester bonds, urethane resins produced using them have the disadvantage that they have poor water resistance.

In order to obtain a new urethane resin overcoming these drawbacks, it has been proposed to use a polyol having a carbonate bond in the molecular structure as a raw material.

At present, the most widely used polycarbonate polyol, that is, a polyol having a carbonate bond in the molecular structure, has 1, as shown in the following formula (I) in the molecular structure.
It has 6-hexanediol as a basic skeleton.

Polycarbonate diol having a 1,6-hexanediol structure in the basic skeleton is a polyurethane resin obtained by using it, mechanical strength, heat resistance, moisture resistance, etc., are very well-balanced, It also has the advantage of being easily manufactured industrially.

[Problems to be Solved by the Invention] However, since the polycarbonate diol having the 1,6-hexanediol structure in the basic skeleton has crystallinity, the polyurethane resin obtained by using the polycarbonate diol is There is a disadvantage that the low-temperature characteristics are inferior.

On the other hand, polyetherol having excellent low-temperature characteristics has a problem of lacking heat resistance.

The present inventors have studied to solve these problems and developed a polycarbonate diol capable of synthesizing a polyurethane having excellent mechanical strength, excellent moist heat resistance, and improved low-temperature properties. .

[Constitution of the Invention] That is, the present invention relates to a polycarbonate diol obtained by reacting a diol compound with one compound selected from the group consisting of a compound requiring a dehydrochlorination step, an alkylene carbonate, a diaryl carbonate, and a dialkyl carbonate. When the diol compound used is polytetramethylene glycol and / or polypropylene glycol having a molecular weight of 400 to 2,000 and a polyhydric alcohol having a carbon number of 20 or less (not having a molecular weight of 400).
A polycarbonate diol comprising about 2000 to 20% by weight (excluding polytetramethylene glycol and polypropylene glycol).

Among the compounds which are one component of the polycarbonate diol in the present invention, compounds requiring a dehydrochlorination step include phosgene and bischloroformate.

Examples of the alkylene carbonate include ethylene carbonate, 1,2-propylene carbonate, and 1,2-butylene carbonate.

Examples of the diaryl carbonate include diphenyl carbonate and dinaphthyl carbonate.

Examples of the dialkyl carbonate include dimethyl carbonate and diethyl carbonate. Each of these can be reacted with a diol compound described below to form a polycarbonate diol by a known method.

The component in the present invention is polytetramethylene glycol and / or polypropylene glycol.

It is essential that these have a molecular weight of 400-2000.

When the molecular weight is 400 or less, the characteristics of polytetramethylene glycol and / or polypropylene glycol are not sufficiently exhibited, and the low-temperature characteristics of the resulting carbonate diol are not improved.

In addition, when polytetramethylene glycol and / or polypropylene glycol having a molecular weight of more than 2,000 are used, the molecular weight of the carbonate diol to be obtained is at least a minimum in order to obtain the characteristics of carbonate diol.
4000 to 5000.

The polyol having such a molecular weight is substantially meaningless as a urethane raw material.

80 to 20% by weight of a polyhydric alcohol having 20 or less carbon atoms (excluding polytetramethylene glycol and / or polypropylene glycol having a molecular weight of 400 to 2,000), and polytetramethylene glycol having a molecular weight of 400 to 2000 and / or Or polypropylene glycol
The reaction is carried out by charging so as to have a ratio of 20 to 80% by weight.

The following can be used as the polyhydric alcohol having 20 or less carbon atoms.

Ethylene glycol, 1,2-propanediol, 1,3-
Butanediol, 2-methyl-1,3-propanediol, neopentyl glycol, hydroxypivalic acid ester of neopentyl glycol, 2-methylpentanediol, 3-methylpentanediol, 1,6-hexanediol, 2,2 , 4-Trimethyl-1,6-hexanediol, 3,3,5-trimethyl-1,6-hexanediol, 2,
3,5-trimethylpentanediol and the like.

If the polyhydric alcohol (excluding polytetramethylene glycol and / or polypropylene glycol having a molecular weight of 400 to 2,000) has less than 3 carbon atoms, those having a side chain are not industrially produced. Conversely, even if more than 10 are used, industrially preferable polycarbonate diols cannot be obtained.

If the content of polytetramethylene glycol and / or polypropylene glycol is less than 20% by weight, the obtained polycarbonate diol has poor low-temperature properties, and the desired performance of the present invention cannot be obtained.

If the content of polytetramethylene glycol and / or polypropylene glycol is more than 80% by weight, the characteristics of polyhydric alcohols having 20 or less carbon atoms and the characteristics of carbonate bonds are lost. I can't.

As the dialkyl carbonate used in the present invention, dimethyl carbonate and diethyl carbonate are preferable.

The reaction for obtaining the polycarbonate diol of the present invention using an alkyl carbonate is represented by the following general formula.

(R is an alkyl group, R 'is a polyether polyol or a polyhydric alcohol residue having 20 or less carbon atoms).

In the present invention, when phosgene is used as a compound requiring a dehydrochlorination step, the reaction for obtaining a carbonate diol is represented by the following general formula.

(R is an alkyl group) In the present invention, when bischloroformate is used as a compound requiring a dehydrochlorination step, the reaction for obtaining a carbonate diol is represented by the following general formula.

(R represents an alkyl group and R 'represents an alkylene group.) At this time, the two diol compounds used as the raw materials are randomly incorporated into the molecule by a carbonate bond.

If one is HO-R ¹ -OH and the other is HO-R ² -OH Are randomly present in the molecule.

Crystallinity is broken by the polyether chains being randomly bonded by the carbonate bond, and the resulting carbonate diol exhibits low-temperature properties.

Next, polytetramethylene glycol and / or polypropylene glycol having a molecular weight of 400 to 2,000 20 to 80% by weight polyhydric alcohol having 20 or less carbon atoms (however,
To about 2000 of polytetramethylene glycol and / or polypropylene glycol) with 80 to 20% by weight of an aliphatic diol in which both are mixed. The situation will be described in detail. For the reaction, a catalyst usually used in transesterification can be used.

For example, metals such as lithium, sodium, potassium, rupidium, cesium, magnesium, calcium, strontium, barium, zinc, aluminum, titanium, cobalt, germanium, tin, lead, antimony, arsenic and cerium and alkoxides thereof.

Examples of other suitable catalysts include carbonates of alkali and alkaline earth metals, zinc borate, zinc oxide, lead silicate, lead arsenate, lead carbonate, antimony trioxide, germanium dioxide, cerium trioxide, And aluminum isopropoxide.

Particularly useful and preferred catalysts are magnesium organic acids,
Organic metal compounds such as metal salts of calcium, cerium, barium, zinc, tin, titanium and the like.

The amount of catalyst used is 0.0001% to 1.0% of the total weight of starting materials
Is appropriate.

 Preferably it is 0.001-0.2%.

 The reaction temperature is preferably about 80C to 220C.

In the early stage of the reaction, the reaction is carried out at a temperature near the boiling point of the dialkyl carbonate. As the reaction proceeds, the temperature is gradually raised and the reaction further proceeds.

An apparatus capable of separating the produced diol compound and the raw material dialkyl carbonate is usually a reactor equipped with a distillation tower, in which the reaction is carried out while refluxing the dialkyl carbonate, and the alcohol produced as the reaction proceeds is distilled off.

In the case where the dialkyl carbonate is partly azeotropically dissipated together with the alcohol distilled off at this time, it is better to allow for this dissipated amount when the raw materials are measured and charged.

According to the above reaction formula, the diol compound (n + 1) mol has a logical molar ratio with respect to the dialkyl carbonate nmol, but in practice, the molar ratio of the dialkyl carbonate / diol compound is preferably 1.1 to 1.3 of the logical molar ratio. .

The reaction can be carried out at normal pressure, but can be carried out under reduced pressure, for example, at 1 mmHg to 200 mmHg in the latter half of the reaction to speed up the progress of the reaction.

The molecular weight of the polycarbonate diol in the present invention can be adjusted by changing the reaction molar ratio of the raw material diol compound to dialkyl carbonate, dialkylene carbonate and the like.

That is, the molecular weight can be controlled by adjusting n in the above formula.

The polycarbonate diol of the present invention is hydrolyzed, and the decomposition product is analyzed by gas chromatography or NMR, etc. to obtain polytetramethylene glycol having a molecular weight of 400 to 2,000 and / or polypropylene glycol 20 to 80% by weight having 20 or less carbon atoms. Polyhydric alcohol (however, molecular weight 400
~ 2000 polytetramethylene glycol and / or polypropylene glycol) in a combination of 80-20% by weight.

[Effects of the Invention] The urethane resin obtained from the polycarbonate diol obtained as described above as a raw material has well-balanced properties such as low-temperature properties, mechanical strength, and wet heat resistance, and includes elastomers, adhesives, binders for magnetic tapes, and the like. It can be widely used for various industrial applications. Hereinafter, the present invention will be described with reference to examples.

Example 1 620 g of dimethyl carbonate (6.89 g) was placed in a 2-liter round bottom flask equipped with a stirrer, a thermometer, and a ten-stage plate distillation column.
), 740 g (6.27 mol) of 1,6-hexanediol, 640 g (0.77 mol) of polytetramethylene glycol having a molecular weight of 830 (PTMG800 manufactured by Mitsubishi Kasei Co., Ltd.), and 0.30 g of tetrabutyl titanate as a catalyst. The reaction was carried out under boiling water to distill off methanol.

The temperature of the reaction vessel gradually increased and reached 200 ° C., and when the distillation of methanol almost disappeared, the pressure reduction operation was started, and unreacted substances were distilled off under a reduced pressure of final 20 mmHg to obtain a reaction product. .

The obtained polycarbonate diol was a paste-like substance having an OH value of 55.2 and a melting point of about 30 ° C.

[Example 2] Instead of 640 g (0.77 mol) of polytetramethylene glycol having a molecular weight of 830 (PTMG800 manufactured by Mitsubishi Kasei), a molecular weight of 7 was used.
Example 1 was repeated except that 640 g (0.853 mol) of polypropylene glycol (Sannickes PP750 manufactured by Sanyo Chemical Industries, Ltd.) of 50 was used, and the following results were obtained.

The obtained polycarbonate diol was a viscous liquid having an OH value of 57.1.

Example 3 Example 3 was repeated except that 740 g (6.27 mol) of 3-methylpentanediol was used instead of 1,6-hexanediol.
In the same manner as in Example 1, the following results were obtained.

The obtained polycarbonate diol was a viscous liquid having an OH value of 55.2.

[Example-4] The following results were obtained in the same manner as in Example-1, except that 990 g (11 mol) of 1,4-butanediol was used instead of 1,6-hexanediol.

The obtained polycarbonate diol was a viscous liquid having an OH value of 56.5.

[Example-5] The same results as in Example-1 were obtained except that 3-methylpentanediol was used in a molar ratio of 2/1 instead of 1,6-hexanediol, and the following results were obtained. Was.

The obtained polycarbonate diol was a viscous liquid having an OH value of 55.8.

[Example-6] Instead of 640 g (0.77 mol) of polytetramethylene glycol having a molecular weight of 830 (PTMG800 manufactured by Mitsubishi Kasei), a molecular weight of 6 was used.
50 polytetramethylene glycol (Mitsubishi Kasei Kogyo PT
MG650) was performed in the same manner as in Example 1 except that 640 g (0.98 mol) was used, and the following results were obtained.

The obtained polycarbonate diol was a viscous liquid having an OH value of 57.2.

Comparative Example 1 A polycarbonate diol was obtained in the same manner as in Example 1, except that 100% of 1,6-hexanediol was used as the diol compound.

[Application Example-1] Using the polycarbonate diols obtained in Examples-1 to 6 and Comparative Example-1 as raw materials, a urethane solution was synthesized under the following reaction conditions, and a 150 μm-thick film was formed from the urethane solution.
Was prepared and the physical properties were evaluated.

(Urethane solution reaction conditions)

(1) Compounding polyol 100 parts 1,4-BD (butanediol) 8.3 parts MDI (4,4'-diphenylmethane diisocyanate)
35.6 parts Melting material (DMF) 267.3 parts Note) Polyol (Mw2000) / 1,4-BD / MDI NCO / OH = 1.03 1,4-BD / polyol = 2.0 (2) Cooking schedule 100 parts polyol, 1,4- 8.3 parts of BD and 144 parts of solvent were charged into a reactor and heated to 60 ° C.

 Next, 35.6 parts of MDI was added, and the temperature was further raised.

When the temperature in the reactor reached 80 ° C., the temperature was maintained for several hours.

 Thereafter, the temperature inside the reactor was removed until it reached 60 ° C.

When the temperature reaches 60 ° C., 123.3 parts of a solvent is added and the mixture is aged at the same temperature.

(3) Properties of urethane solution NV (%) = 35 VIS (cp / 25 ° C) = 60-80,000 solvent = DMF (4) Preparation of film A polyurethane solution is coated on a release paper and forcedly dried.

 Finished film thickness (μ) = 150 (5) Physical property measurement JIS No. 3 dumbbell punching measuring machine Shimadzu Autograph Table 1 shows the results.

As shown in Table 1, the urethane film using the carbonate diol of the present invention has excellent low-temperature characteristics.

Claims (1)

(57) [Claims] 1. A polycarbonate diol obtained by reacting a compound requiring a dehydrochlorination step, one selected from the group consisting of alkylene carbonate, diaryl carbonate and dialkyl carbonate with a diol compound, the diol compound used has a molecular weight of 400 to 2000 polytetramethylene glycol and / or polypropylene glycol 20 to 80% by weight Polyhydric alcohol having 20 or less carbon atoms (however, molecular weight 400
A polycarbonate diol comprising a mixture of about 2000 to about 2000 polytetramethylene glycol and / or polypropylene glycol) in a proportion of 80 to 20% by weight.