JPH05239177A - Polyurethane resin - Google Patents

Abstract

(57) [Summary] [Purpose] It is intended to provide a novel polyurethane resin. Constitution: Tetrahydrofuran and 3-alkyltetrahydrofuran having a molar ratio of 85/15 to 20/80 and a molecular weight of 500 to 50 obtained by copolymerizing them.
No. 00 copolyether polyol, a polyisocyanate compound, and a chain extender that reacts with an isocyanate group.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a novel polyurethane resin.

[0002]

Polyether is often used as a soft segment component of polyurethane resins. Above all, a polyurethane resin using polytetramethylene ether glycol, which is a polymer of tetrahydrofuran (hereinafter referred to as THF), is particularly noted because it is excellent in elastic properties, low temperature properties, hydrolysis resistance and the like.

However, polytetramethylene ether glycol has a useful molecular weight of 500 to 4000 for polyurethane.
Of which the melting point is in the range of 20 to 40 ° C., crystallization occurs at room temperature or lower, and handling, workability as well as coating, coating and sealing which require curing at room temperature. It has become a big problem in such fields. Conventionally, in these fields, a method of adding an appropriate organic solvent has been adopted in order to prevent crystallization, but recently, from the viewpoint of pollution prevention and rationality, a non-solvent type has been aimed, and polytetramethylene ether While the characteristics of terglycol are desired, it is strongly desired to improve the crystallinity thereof.

To improve the disadvantages of polytetramethylene ether glycol, THF / propylene oxide copolyether polyol is known [Journal of
Polymer Science, 58, 857
-863 (1962)]. However, since this polyol is a copolymer with propylene oxide, it has a secondary hydroxyl group at the end like polypropylene oxide polyol,
Although it has a low reactivity with an isocyanate group, has a difficulty in the physical properties of polyurethane, has a low crystallinity, and maintains a liquid state at room temperature, it is not satisfactory.

[0005]

As a result of various studies on polyurethane resins having improved properties, the present inventors have completed the present invention, and the object of the present invention is to obtain excellent tensile strength, low temperature physical properties, and anti-stretchability. A new polyurethane resin having physical properties such as properties is provided.

[0006]

SUMMARY OF THE INVENTION The gist of the present invention is to obtain a copolymer of tetrahydrofuran and 3-alkyltetrahydrofuran having a molecular weight of 500 to 5000 obtained by copolymerizing them in a molar ratio of 85/15 to 20/80. A polyurethane resin obtained from copolyetherpolyol, a polyisocyanate compound, and a chain extender that reacts with an isocyanate group.

That is, in the present invention, THF and 3-
Alkyl THF in a molar ratio of 85/15 to 20/80
The copolyetherpolyol having a molecular weight of 500 to 5,000 obtained by the copolymerization reaction under a strong acid catalyst at a mixing ratio of is kept liquid at room temperature and is highly reactive with polyisocyanate. A polyurethane resin obtained by reacting a polyisocyanate with a chain extender has excellent rubber elasticity.

The 3-alkyl-substituted tetrahydrofuran used in the present invention has the general formula:

[0009]

[Chemical 1]

(Wherein _one of R ₁ and R ₂ is hydrogen and the other is C ₁ -C ₄ alkyl group), the structural formula is represented by 3-methyl THF. It is synthesized by hydroformylation and hydrogenation of 1,4-butenediole as described by Copelin in US Pat. No. 3,859,369, and by reduction of itaconic acid and the like. It is known that THF and 3-methyl THF undergo a copolymerization reaction.

Copolyether as the diol component of the present invention
Terpolyol is a mixture of THF and 3-methyl THF at a molar mixing ratio of 85/15 to 20/80, and is usually adjusted to 0 by a strong acid capable of ring-opening THF, such as chlorosulfonic acid, fluorosulfonic acid, perchloric acid. It is obtained by copolymerization at a temperature of 50 ° C to 50 ° C and has a molecular weight of 500 to 5,000.
And, its melting point is around 10 ° C. or less, and it maintains a liquid state completely at room temperature. When the THF / 3-methylTHF ratio is made small in the above molar mixing ratio range, the melting point tends to decrease, and therefore the melting point can be freely changed to obtain a copolyether having a melting point suitable for the use temperature and purpose. be able to. When the molar mixing ratio is 20/80 or less, copolyether having substantially no melting point is obtained, but its glass transition point rises sharply, which is not preferable for the low temperature characteristics of the polyurethane resin. On the other hand, if the molar mixing ratio is 85/15 or more, the melting point is increased and the crystallinity is increased, which is not suitable for the purpose.
From the balance of crystallinity and physical properties of polyurethane resin, a molar ratio of THF / 3-methyl THF for obtaining a preferred copolyether polyol is 80/20 to 30/70.

The molecular weight of the polyol is 500 to 5 as a value measured by the gel permeation method.
Has 000. However, when the molecular weight is 500 or less, the polyurethane resin becomes hard, and the rubber elastic modulus and tensile strength are lowered, and when the molecular weight is 5000 or more, the elongation becomes too large and the characteristics as a resin are impaired.

The above-mentioned copolyetherpolyol is a colorless and transparent liquid at room temperature, and since it has a primary hydroxyl group at the end, it is highly reactive with an isocyanate group, and it has a high reactivity with polypropylene oxide polyol or THF / propylene oxide copolymer. It is about 3 to 4 times more reactive than the polyether polyol.
Therefore, even in the field of polyurethane resin, room temperature curing process,
Further, it is suitable for a reaction injection molding (RIM) process and the like.

On the other hand, the polyisocyanate compound is a compound having two or more isocyanate groups in the molecule, such as tolylene diisocyanate (TDI) and 4,4'-diphenylmethane diisocyanate ( MDI), hexamethylene diisocyanate, xylylene diisocyanate
, Isophorone diisocyanate, naphthylene diisocyanate, hydrogenated diphenylmethane diisocyanate, and the like, and polyisocyanate compounds generally used for the synthesis of polyurethane resins, and these may be used alone or in combination of two or more. Used as a mixture.

As the chain extender which reacts with the isocyanate group, a compound used as a chain extender in the synthesis of polyurethane resin, which is a compound having two or more hydroxyl groups and amino groups, ethylene glycol, Propylene glycol, 1,4-butanediol, 1,6-hexanediol, xylylene glycol, glycerin, trimethylolpropane, ethylenediamine, propylenediamine, phenylenediamine, diaminodiphenylmethane, methylene bis (2- Chloroaniline) and the like. Other examples include hydrazine compounds and water. The resin obtained using diamine, hydrazine and water is polyurethane-urea. In the polyurethane resin of the present invention, for example, a copolyetherpolyol compound and a polyisocyanate compound are reacted to synthesize an isocyanate group-containing precursor (prepolymer), and then a chain extender is reacted. That is, it can be obtained by a two-step method, or can be obtained by a conventional method for producing a polyurethane resin such as a one-shot method in which copolyetherpolyol, polyisocyanate and a chain extender are simultaneously reacted.

In the above synthesis, the reaction temperature is the process,
50 to 20 in general, depending on the application etc.
The reaction is carried out at a temperature of 0 ° C, but in the case of the present invention, the reaction is possible even at a temperature of 50 ° C or lower because the melting point of copolyetherpolyol is low. On the other hand, the composition ratio of each component varies depending on the intended polyurethane resin, but the prepolymer must contain an isocyanate group, and the isocyanate of the polyisocyanate compound is equivalent to 1 equivalent of the hydroxyl group of the copolyetherpolyol compound. The number of groups is 1 or more, preferably 1 or more and 3.5 or less. The compounding ratio of the final reaction product is such that the total active hydrogen atom equivalents of the copolyether polyol and the chain-extending compound are 0.9 to 1.1 with respect to 1 equivalent of the isocyanate group in any method.

In the above reaction, a catalyst, a stabilizer and the like can be added if necessary. Examples of the catalyst include triethylamine, tributylamine, dibutyltin dilaurate, stannous octoate, and the like, and examples of the stabilizer include ionol (BHT), distearyl thiodipropionate, dibeta. Naphthylphenylenediamine,
Examples thereof include tri (dinonylphenyl) phosphite.

The polyurethane resin of the present invention is considerably superior to the physical properties of the polyurethane resin obtained from polypropylene oxide polyol and THF / propylene oxide copolyether polyol which are liquid at room temperature, and is obtained from polytetramethylene ether polyol. It is an excellent elastic body that is almost the same as the physical properties of the polyurethane resin used.

[0019]

EXAMPLES The present invention will now be described in more detail by way of examples. The hydroxyl value (OH value mg KOH / g) of copolyether polyol in the examples was determined by the pyridine-acetic anhydride method, and the number average molecular weight was determined therefrom. 3-methyl TH
The composition analysis of the F unit and the THF unit and the terminal hydroxyl group analysis are carried out by ¹³ C-NMR (FX-60 manufactured by JEOL Ltd.), melting point (T
m) and the glass transition point (Tg) were determined by DSC (DSC-8230 manufactured by Rigaku Denki). Polyurethane properties are JI
It measured according to S-K6301.

Example 1 288.4 g (4 mol) of dehydrated THF and 8601 g (1 mol) of 3-methyl THF [molar mixing ratio 80/20]
Was charged in a 1-liter four-neck separable flask equipped with a stirrer, a thermometer, and an N ₂ seal device, and 70% perchloric acid (10.5 g) and acetic anhydride (95 g) were added at a temperature of 10 ° C. to carry out a polymerization reaction for 8 hours. went. The reaction-terminated liquid was neutralized with 500 g of a 20% sodium hydroxide aqueous solution, and the following general method was followed to prepare a monomer.
275 g of copolyether glycol, which is a colorless and transparent liquid at room temperature (yield 7
3.4%) was obtained. This product has a hydroxyl value of 103.9, a number average molecular weight of 1080, and as a result of NMR analysis, it has only a primary hydroxyl group at the terminal, and the molar composition ratio of the THF unit and the 3-methylTHF unit is 86/14 in copolyether glycol. Met. As a result of DSC analysis, Tm = 1 ° C., T
It was g = -85 ° C. Stirrer, thermometer, N ₂ series
100 g of the above copolyether glycol was placed in a 500 cc four-neck separabar flask equipped with a vacuum device.
It was vacuum dried at 100 ° C. for 1 hour, dissolved and mixed in 100 g of sufficiently dehydrated dimethylacetamide, and distilled and purified to give 4,4-diphenylmethane diisocyanate (MD
I) and a known method [J. poly. sci.
chem. Eds. , 13, 1657 ('75)]
Reaction rate constant K ₁ (kg / eg · s
ec), K ₁ = 4.3 × 10 ⁻³ was obtained, and THF / propylene oxide copolyether glycol (molecular weight 980, K = 1.2 × 10 5) measured at the same time was obtained.
￣ ³ ), polypropylene oxide glycol (molecular weight 1
000, K ₁ = 0.9 × 10 ⁻³ ), which is about 4 times. Next, 200 g of the above copolyether glycol was placed in a similar 500 cc separable flask, and the mixture was kept at 100 ° C. for 1 hour.
After vacuum-drying for an hour, 106 g of MDI was added, and the mixture was reacted at 60 ° C. for 5 hours to give a prepolymer (NCO = 6.50%).
Got After taking 150 g of this in a mixer prepared separately, after degassing, 10 g of 1,4-butanediol was added, and after thoroughly mixing for several minutes, poured into a preheated 20 cm × 30 cm × 0.2 cm glass mold and heated at 110 ° C. Curing was carried out for 16 hours in a bun to obtain a polyurethane sheet. This was left to stand in a thermostatic chamber at 20 ° C. for 1 hour and subjected to physical property measurement. Table 1 shows the physical properties of the prepolymer and the polyurethane resin.

[0021]

[Table 1]

Examples 2 to 4 and Comparative Examples 1 and 2 The molar mixing ratio of THF and 3-methyl THF was 50/50.
(Example 2), 30/70 (Example 3), 90/10
(Comparative Example 1), 10/90 (Comparative Example 2), 80/20
(Molecular weight 2000, Example 4), and copolyether glycol obtained in the same manner as in Example 1 except that the amount of perchloric acid / acetic anhydride was changed to match the target molecular weight.
The physical properties of the polyurethane resin are shown in Table 1.

Comparative Examples 3 and 4 Commercially available polytetramethylene ether glycol (PT
G, molecular weight 1020), THF / propylene oxide (30% by weight) copolyether glyco-obtained by a known method.
Table 1 shows the properties of polyurethane (PPTG, molecular weight 980) and the polyurethane obtained in the same manner as in Example 1.

[0024]

As described above, the polyurethane resin of the present invention is excellent as shown in Table 1 by using copolyetherpolyol of tetrahydrofuran and 3-alkyltetrahydrofuran as the polyol component. A polyurethane resin could be provided.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Haruo Watanabe 7-43, Oguro-cho, Tsurumi-ku, Yokohama-shi, Kanagawa Hodogaya Chemical Industry Co., Ltd. Central Research Laboratory Tsurumi Branch Office (72) Inventor Shuichi Takeuchi Yokohama-shi, Kanagawa 7-43, Oguro-cho, Tsurumi-ku, Tsurumi Branch Office, Central Research Laboratory, Hodogaya Chemical Co., Ltd.

Claims (1)

[Claims] 1. A molar ratio of tetrahydrofuran to 3-alkyltetrahydrofuran of 85/15 to 20/80.
Molecular weight 500 obtained by copolymerizing these at a mixing ratio of
Up to 5000 copolyether polyols, polyisocyanate compounds, and a polyurethane resin obtained by reacting with a chain extender that reacts with an isocyanate group.