JP2884358B2 - Polyurethane - Google Patents

Description

The present invention relates to a polyurethane. More specifically, the present invention relates to polyurethanes having excellent low temperature properties.

[Prior Art] Polyurethane resins are used in many fields such as foams, adhesives, elastomers, fibers, and paints, and the main raw materials are polyisocyanates and polyols. Polyols such as polypropylene glycol and polyether polyols such as polytetramethylene glycol, polyester polyols derived from dihydric carboxylic acids such as adipic acid and polyhydric alcohols, and lactones are obtained by reacting with alcohols. Polylactone polyol and the like are used, and various uses are properly used according to the required performance.

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

On the other hand, polyester polyols and polylactone polyols have an ester bond, and therefore have a drawback that urethane resins produced using the same 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. Currently, the most widely used polycarbonate polyol, that is, a polyol having a carbonate bond in the molecular structure, has 1,6-hexanediol as a basic skeleton as shown in the following formula (II) in the molecular structure. .

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 Improved by the Invention] However, the polycarbonate diol having the 1,6-hexanediol structure in the basic skeleton has a melting point of 40%.
Since it is a wax-like solid at a temperature of from 50 ° C. to 50 ° C., that is, at room temperature, it is usually necessary to heat and use a melting tank or the like before use.

On the other hand, polyether polyols having excellent low-temperature properties have a problem that they lack heat resistance. The present inventors have solved the above problems and have studied to develop a polyurethane having excellent low-temperature characteristics. As a result, the present inventors have reached the present invention.

[Constitution of the Invention] That is, the present invention provides a polycarbonate diol obtained by reacting an aliphatic diol 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. Wherein the aliphatic diol used is represented by the following formula (I): 20 to 80 parts by weight of an alkylene oxide adduct of 2,2-hist (4-hydroxyphenyl) propane represented by the formula (where R is a hydrogen or methyl group, Ph is a residue of a phenyl group having a bond at the para position, m and n is an integer of 1 to 3), and is obtained by reacting a polycarbonate diol made of a mixture of 1,6-hexanediol at a ratio of 80 to 20 parts by weight with a polyisocyanate, and has excellent low-temperature characteristics. Polyurethane ".

Among the compounds which are one component of the polycarbonate diol which is one of the raw materials in the polyurethane of 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 polyhydric alcohol described below to form a polycarbonate diol by a known method.

In the polyurethane of the present invention, the compound which is another component in the polycarbonate diol which is one raw material is an alkylene oxide adduct of 2,2-bis (4-hydroxyphenyl) propane represented by the formula (I), which is a known substance. It is widely used in the industrial field, such as being used as one of the polyol components of urethane.

To produce an alkylene oxide adduct of 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (4-hydroxyphenyl) propane and sodium ethylate, caustic soda, caustic potash, amines and the like and a basic catalyst Alternatively, it can be obtained by charging an acid catalyst such as BF3 or the like and a solvent into a reaction vessel, press-injecting ethylene oxide or propylene oxide into the reaction vessel, and reacting while heating and stirring. However. The addition amount of the alkylene oxide is preferably 2 to 4 mol per 1 mol of 2,2-bis (4-hydroxyphenyl) propane, that is, the reaction is performed so that the values of n and m become 1 to 3. If lower, a part of the phenolic hydroxyl groups of 2,2-bis (4-hydroxyphenyl) propane remains and the reactivity differs from the aliphatic primary alcoholic hydroxyl groups, so that polyurethane is used.
When it is used as a raw material such as polyester, it is not preferable, and the n- and m-values are 5 or more. This is not preferred because the properties are reduced.

In the polyurethane of the present invention, an alkylene oxide adduct of 2,2-bis (4-hydroxyphenyl) propane represented by the formula (I), which is a component of the polycarbonate diol which is one of the raw materials, is 20 to 80 parts by weight, 6−
Hexanediol is charged and reacted at a ratio of 80 to 20 parts by weight. When the amount of the alkylene oxide adduct of 2,2-bis (4-hydroxyphenyl) propane is less than 20 parts by weight, the obtained polycarbonate diol has poor low-temperature properties, and thus the desired performance of the present invention cannot be obtained. Also, 2,2-bis (4-hydroxyphenyl)
If the alkylene oxide adduct of propane is more than 80 parts by weight, the characteristics of 1,6-hexanediol and carbonate bonds are lost, and the polyurethane of the present invention synthesized using the compound cannot obtain mechanical strength or the like.

If the polyhydric alcohol has less than 3 carbon atoms, those having a side chain are not industrially produced. Conversely, even if the amount exceeds 20, no preferable industrially excellent polycarbonate diol can be obtained.

As the dialkyl carbonate used in the present invention, dimethyl carbonate and diethyl carbonate are preferable. The reaction for reacting a dialkyl carbonate with an aliphatic diol to obtain a polycarbonate diol in the polyurethane of the present invention is represented by the following general formula.

[R is an alkyl group or chlorine; R 'is represented by the formula (I)
Alkylene oxide adduct of 2,2-bis (4-hydroxyphenyl) propane or 1,6-hexanediol residue] At this time, the two diol compounds used as the raw materials are randomly incorporated into the molecule by a carbonate bond. I'm sorry.

If one is HO-R ¹ -OH and the other is HO-R ² -OH, React randomly and exist in the molecule.

Since the polyether chains are randomly bonded by the carbonate bond, the crystallinity of the 1,6-hexanediol skeleton is broken, and the obtained carbonate diol exhibits low-temperature characteristics. 2,
Because of the phenylene group contained in the alkylene oxide adduct of 2-bis (4-hydroxyphenyl) propa,
It has heat resistance characteristics.

Then, both 20 to 80 parts by weight of an alkylene oxide adduct of 2,2-bis (4-hydroxyphenyl) propane represented by the formula (I) and 80 to 20 parts by weight of 1,6-hexanediol were mixed. In the case where a dialkyl carbonate is used as one of the raw materials for the reaction with the aliphatic diol, the situation of the reaction procedure and the like will be described in detail.

For the reaction, a catalyst usually used in transesterification can be used. For example, lithium, sodium, potassium, rupidium, cesium, magnesium, calcium, stylonium, barium, zinc, aluminum,
There are metals such as titanium, cobalt, germanium, tin, lead, antimony, arsenic and cerium and their alkoxides. To give another example of a suitable catalyst,
There are alkali and alkaline earth metal carbonates, 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 organometallic compounds such as metal salts of organic acids magnesium, calcium, cerium, barium, zinc, tin, titanium and the like. The amount of the catalyst used is suitably 0.0001% to 1.0% of the total weight of the starting materials. Preferably 0.0
01 to 0.2%.

Further, the reaction temperature is preferably about 80 ° C to 220 ° C. 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.

A device capable of separating the produced alcohol and the raw material dialkyl carbonate is usually a reactor with a distillation tower,
The reaction is carried out while refluxing the dialkyl carbonate, and the alcohol produced as the reaction proceeds is distilled off. At this time, the dialkyl carbonate is partly azeotropically dissipated together with the alcohol distilled off, so that it is better to allow for this dissipated amount when the raw materials are measured and charged.

According to the above reaction formula, the theoretical molar ratio of aliphatic diol (n + 1) to the molar ratio of dialkyl carbonate is 1.1 to 1.3 times the theoretical molar ratio of dialkyl carbonate / aliphatic diol. Is good.

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 polyurethane of the present invention can be adjusted by changing the reaction molar ratio between the raw material aliphatic diol and dialkyl carbonate, dialkylene carbonate, or the like. That is, the molecular weight can be controlled by adjusting n in the above formula.

The polycarbonate diol in the polyurethane of the present invention is hydrolyzed, and the decomposition product is analyzed by gas chromatography or NMR to obtain 2,2-bis (4-hydroxyphenyl) propane represented by the following formula (I). 20 to 80 parts by weight of an alkylene oxide adduct of It can be confirmed that 1,6-hexanediol is used in a combination of 80 to 20 parts by weight.

[Effect of the Invention] Since the urethane resin of the present invention obtained as described above is obtained using the above-mentioned polycarbonate diol as a raw material, the urethane resin has a good balance of low-temperature characteristics, mechanical strength, heat resistance, moisture resistance, etc. , Adhesives, binders for magnetic tapes, and various other industrial uses. Hereinafter, the present invention will be described with reference to examples.

[Production Example-1] In a 3-liter round bottom flask equipped with a stirrer and a 10-stage perforated distillation column, 770 g of dimethyl carbonate (8.55
Mol), 740 g (6.27 mol) of 1,6-hexanediol, 2,2
Alkylene oxide adduct of 2,2-bis (4-hydroxyphenyl) propane obtained by adding and reacting 2 mol of ethylene oxide with respect to 1 mol of -bis (4-hydroxyphenyl) propane (Nippon Emulsifier Co., Ltd.) 740 g (2.28 mol) of Newcol-1900 (OH product, 346) and 0.30 g of tetrabutyl titanate as a catalyst were charged, and the reaction was carried out under normal pressure under boiling dimethyl carbonate to distill off methanol. The temperature of the reaction vessel gradually increased and reached 200 ° C., and when the distillation of methanol was almost stopped, the decompression operation was started, and unreacted components were distilled off under a reduced pressure of final 20 mmHg to obtain a reaction product. . The obtained polycarbonate diol was a liquid having an OH value of 56.2.

[Production Example-2] The same apparatus as in Production Example 1 was used, and as a diol compound
Polycarbonate diol was similarly obtained using 1,6-hexanediol at 100%.

[Example-1] Using the polycarbonate diol obtained in Production Example-1 and Production Example-2 as a raw material, a polyurethane was synthesized under the following reaction conditions, and a urethane film having a thickness of 150 µm was prepared from this polyurethane. Physical properties were evaluated.

[Urethane solution reaction conditions] (1) Blending composition Polyol 100 parts 1,4-BG 8.3 parts MDI 35.6 parts Solution (DMF) 267.3 parts Note) Polyol (Mw2000) / 1,4-BG / MDI NCO / OH = 1.03 1 , 4-BG / polyol = 2.0 (2) Cooking schedule 100 parts of polyol, 8.3 parts of 1,4-BG and 144 parts of a solvent are charged into a reactor and heated to 60 ° C. Then, MDI35.
Add 6 parts and heat further. When the temperature of the reactor reaches 80 ° C., the reaction is continued for several hours. Thereafter, the temperature of the reactor is removed until it reaches 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 polyurethane 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 dried by force.

Finished film thickness: 150 microns (5) Physical property measurement JIS No. 3 dumbbell punching Measurement device: Shimadzu Autograph Table 1 shows the obtained results.

As is clear from the results in Table 1, the urethane film using the polyurethane of the present invention is particularly excellent in low-temperature characteristics.

Claims (1)

(57) [Claims] An aliphatic diol used in a polycarbonate diol obtained by reacting an aliphatic diol 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. Is the following formula (I) 20 to 80 parts by weight of an alkylene oxide adduct of 2,2-bis (4-hydroxyphenyl) propane represented by the following formula (where R is a hydrogen or methyl group, Ph is a residue of a phenyl group having a bond at the para position, m And n is an integer of 1 to 3), and is excellent in low-temperature characteristics characterized by reacting a polycarbonate diol made of a mixture of 1,6-hexanediol at a ratio of 80 to 20 parts by weight and polyisocyanate. Polyurethane.