JPS6222817A - Production of polyurethane - Google Patents

Abstract

PURPOSE:To obtain a polyurethane improved in hydrolysis resistance, flexibility in a low-temperature (e.g., -20 deg.C) atmosphere and abrasion resistance, by reacting a specified polyol with a polyisocyanate. CONSTITUTION:In the production of a polyurethane comprising a high-molecular polyol and an organic polyisocyanate, a high-MW polyol having a group of the formula in the molecule is used as said polyol. Preferred examples of said polyol include a polyester polyol of average MW of 500-30,000, obtained by reacting 2-methyl-1,8-octanediol or a mixed glycol containing this diol with a dicarboxylic acid, or a polycarbonate polyol of average MW of 500-30,000, obtained by reacting 2-methyl-1,8-octanediol or a mixed polyol containing this diol with a dicarbonate.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a novel process for preparing polyurethanes from polyester polyols or polycarbonate polyols and polyisocyanates.

Conventional technology Conventionally, polyurethane is produced by reacting high-molecular polyols and polyisocyanates, and, if desired, low-molecular compounds having two or more active hydrogen atoms as raw materials. . Examples of polymeric polyols include dicarphonic acid components such as aliphatic dicarboxylic acids such as succinic acid, glutaric acid, adipic acid, azelaic acid, and sebacic acid, ethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol, .A polyester polyol obtained by condensation polymerization with a glycol component such as 6-hexanediol,
Ester-type polymeric polyols such as polycarbonate polyols obtained by transesterification of l,6-hexanediol and diphenyl carbonate are used [Keiji Iwata, "Polyurethane Resins", Nikkan Kogyo, March 33, 1975. (Published by a newspaper company), see pages 56-61].

However, polyurethane produced using the above-mentioned polyester polyol as a polymeric polyol has poor hydrolysis resistance. Therefore, when the polyurethane is made into a film,
The surface becomes sticky or cracks within a relatively short period of time. Therefore, the use of this polyurethane is limited. In order to improve the hydrolysis resistance of this type of polyurethane, it is effective to reduce the concentration of ester groups in polyester polyol residues present as polymeric polyol residues in the polyurethane. For this purpose, the use of polyester polyols obtained from glycols and dicarboxylic acids having a large number of carbon atoms as polymeric polyols gives preferable results. However, although the polyurethane obtained using such a polyester polyol has excellent hydrolysis resistance, it has a large tendency to crystallize, and the polyurethane obtained by using, for example, -
When left in a low-temperature atmosphere such as 20° C., flexibility, represented by bending resistance, decreases significantly.

Furthermore, polyurethane produced using the above-mentioned polycarbonate polyol as a polymeric polyol has a drawback of poor low-temperature properties because the above-mentioned polycarbonate polyol itself has a high freezing point.

An object of the present invention is to provide a new method for producing polyurethane.

Another object of the present invention is to provide a method for producing polyurethane having excellent hydrolysis resistance, excellent flexibility under a low temperature (for example, -20°C) atmosphere, and excellent abrasion resistance.

Means for Solving the Problems According to the present invention, the above object is achieved in a method for producing polyurethane from a polymeric polyol and an organic polyisocyanate, in which 〒H3 -0-CH2-CH (CH2〇) is present in the molecule as the polyol. This is achieved by a method for producing polyurethane characterized by using a polymer polyol having a group represented by CH2-0(I).In particular, as the polymer polyol, 2-methyl-1,8-octanediol or the diol is used. A polyester polyol with an average molecular weight of 500 to 30,000 obtained by reacting a mixed glycol mainly composed of dicarboxylic acid or 2-methyA/-1,8-octanediol or a mixed glycol mainly composed of this diol and a dicarboxylic acid. This is very easily achieved by using polycarbonate polyols having an average molecular weight of 500-30,000 obtained by reacting carbonates.

The polymer polyol used in the present invention is a polymer polyol containing a group represented by the above CI) as a glycol residue, and typical examples thereof are polyester polyol-yv- or polycarbonate represented by the above CI). It is polio. It is essential that the group represented by CI) is present in the polymer polyol, and a typical compound providing this group is 2-methyl-1,8
-octanediol. This group suppresses crystallization of polyurethane. In order to suppress crystallization of polyurethane, polymeric diol glyco/
Glycols that can form L' residues include neopentyl glycol, 2-methyl-1,3-propanediol, 1
．． It is known to use 3-butylene glycol and propylene glycol glycols having alkyl side chains, but these glycols have not been used alone or in the form of mixtures without deteriorating hydrolysis resistance. It is not possible to obtain a polyurethane that is both flexible and amorphous and also has good low-temperature flexibility.

In addition to the group represented by CI), the polymer polyol may also include a group represented by the general formula % formula % [] (wherein n represents an integer from 6 to 9-), that is, a group represented by the general formula %Residues of diols represented by formula %(
represents an integer from 1 to 3), that is, the residue of a branched alkanediol represented by the general formula % [).

In the group represented by [■] above, n is an integer of 6 to 9, preferably 6' or 9.

(Representative compounds providing the group represented by III, that is, alkanediols represented by the general formula [■a] include 1,9-nonanediol and 1,6-hexanediol. In the group represented, m is an integer of 1 to 3, preferably 2.[I[Representative compounds providing the group represented by I],
That is, the branched alkanediol represented by the general formula C[Ia] includes 3-methyl-1,5-bentanediol. In addition, these compounds have a carbon number of 5
The use of the following other diols also results in a significant decrease in the hydrolysis resistance and low temperature flexibility of the polyurethane.

In the present invention, the group represented by (I) in the polyester polyol or polycarbonate polyol is present at 10% by weight or more, preferably at least 15% by weight, more preferably at least 20% by weight of the total glyco/L/residues. % or more, and may be 100% by weight. Further, the proportion of the groups represented by [■] and [I[[] is preferably 90 or less, preferably 1% by weight, and more preferably 80% by weight of the total glycol residues. As the ratio of the group represented by [■] above increases, and the sum of the ratio and the ratio of the group represented by (III) increases within the ratio defined above, the polyester polyol/L/ma Polycarbonate polyols change from a solid state to a cypenate state, and then to a liquid state, and their melting points decrease.Therefore, when these polyols are used as polymeric polyols, they can be used to improve workability during polyurethane production. However, a polyurethane with no crystal hardening and excellent low-temperature flexibility can be obtained.

In addition, when the above-mentioned [I], CI [') and [■] are present in the molecule, the polymer polyol becomes a polymer diol. For polymeric polyol-μ, it is necessary to have, for example, trimethylolpropane residues present depending on the number of hydroxyl groups used in the polyol.

The dicarboxylic acid for producing the polyester polyol used in the present invention is preferably an aliphatic or aromatic dicarboxylic acid having 5 to 12 carbon atoms. Among them, aliphatic dicarboxylic acids are preferred.

Examples of aliphatic dicarboxylic acids include glutaric acid, adipic acid, pimelic acid, speric acid, azelaic acid, sepacic acid, etc., and examples of aromatic dicarboxylic acids include phthalic acid, terephthalic acid, isophthalic acid, etc. It will be done. In order to obtain a polyurethane which is particularly excellent in hydrolyzability and flexibility under a low temperature atmosphere, it is preferable to use adipic acid, azelaic acid or cepatic acid, and especially to use azelaic acid. These dicarboxylic acids may be used alone or in combination of two or more.

The polyester polyols used in the present invention can be produced by methods similar to the known methods used in the production of polyethylene terephthalate or polybutylene terephthalate, namely transesterification or direct esterification followed by melt polycondensation. be. Its molecular weight is 500-30,000 preferably 600-s, o o
It is desirable that it be within the range of o. Also, the number of hydroxyl groups present in the polyester polyol varies depending on the use of the final polyurethane, although it cannot be generalized.
It is preferable that the number per molecule is 2 or more, particularly in the range of 2 to 4.

Further, as the dicarbonate for producing the polycarbonate polyol used in the present invention, dialkyl carbonate or diaryl carbonate is preferable. Among them, diaryl carbonate and especially didiphenyl carbonate are preferred.

The polyester polyol used in the present invention can be produced by a method similar to the known method used in the production of polycarbonate from diphenyl carbonate and bispheno-/I/A, ie, by transesterification. The average molecular weight is desirably in the range of 500 to 30,000, preferably 600 to s, ooo. In addition, the number of hydroxyl groups present in polycarbonate polyol varies depending on the use of the final polyurethane.
-Although it cannot be said generally, 2 or more per molecule, especially 2 or more
Preferably, the number is in the range of 4.

Suitable polyisocyanates used in the present invention include known aliphatic, alicyclic, and aromatic organic polyisocyanates containing two or more isocyanate groups in the molecule, particularly 4,4'-diphenylmethane diisocyanate;
Diisocyanate such as P-phenyl diisocyanate, toluylene diisocyanate, 1.5-naphthylene diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, trimethylolpropane or glycerin 1 mol Examples include triisocyanate to which 3 mol of tolylene diisocyanate is added.

In addition, in the present invention, a suitable chain extender may be used as desired, and the chain extender includes a chain extender commonly used in the polyurethane industry, that is, a chain extender containing at least two hydrogen atoms capable of reacting with isocyanate. molecular weight 40
0 or less low molecular weight compounds, such as ethylene glycol, l
, 4-butanediol, xylylene glycol, bishydroxybenzene, neopentyl glycol, 3,3-
Examples include dichloro-4,4'-diaminodiphenylmethane, isophorone diamine, 4,4'-diaminodiphenylmethane, hydrazine, dihydrazide, trimethylolpropane, and glycerin.

As for the operating method for obtaining polyurethane, known urethanization reaction techniques are used. For example, after preheating polymer Polio-IV or a mixture of it and a low molecular compound having active hydrogen to about 40 to 100°C, the ratio of the number of active hydrogen atoms to isocyanate groups of these compounds is about 1.
Polyisocyanate is added in a ratio of 1:1, stirred vigorously for a short period of time, and left to stand at about 50 to 150°C to obtain a polyurethane. Alternatively, a method of obtaining polyurethane via a urethane prepolymer can also be used. Polyisocyanate is usually used in a very small excess because it is affected by moisture and other factors. These reactions are performed using dimethylformamide, diethylformamide, dimethylsulfoxide, dimethylacetamide, tetofhydrofuran, isopropanol, benzene, toluene,
It can also be carried out in a solvent consisting of one or more of ethyl cellosolve, trichlene and the like. In this case, it is convenient to set the polyurethane solution concentration within the range of 10 to 40% by weight in order to obtain a polyurethane having a high molecular weight.

The average molecular weight of the resulting polyurethane is generally 5.00.
0-500,000, preferably 10,00.0-3
Preferably, it is in the range of 00,000.

Next, some examples of how the polyurethane obtained by the present invention is used will be described.

(1) Substantially linear pellets of thermoplastic polyurethane are produced, heated and melted to produce shellastomer products by methods such as injection molding, extrusion molding, and calendering.

(2) Mix the polymer polyol, polyisocyanate, and chain extender together, or react the polymer polyol and polyisocyanate in advance to synthesize a prepolymer having terminal incyanate groups or terminal hydroxyl groups; Mix chain extender or polyisocyanate,
Use as cast elastomer products or as paints, adhesives, etc.

(3) A polyurethane solution is obtained by synthesizing polyurethane by dissolving polyurethane in a solvent or by synthesizing polyurethane in a solvent, and this is used as a coating agent impregnating agent or a wind blower for synthetic leather, artificial leather, fibers, etc. Used as a conditioning agent.

(4) The terminal isocyanate prepolymer is dissolved in a solvent, a chain extender and the like are added thereto to prepare a stable spinning stock solution, and elastic fibers are produced from this stock solution by a wet method or a dry method.

(5) Various additives such as a foaming agent are blended into a polymeric polyol, a polyisocyanate or a prepolymer having terminal isocyanate groups is added thereto, and the mixture is stirred at high speed to foam to produce a foam product.

More specifically, the polyurethane obtained by the present invention can be used in sheets, films, rolls,
Gears, solid tires, belts, hoses, tubes, anti-vibration materials, backing materials, shoe soles (Microcell, etc.), artificial leather, fiber treatment agents, cushioning agents, paints, adhesives, sealants, waterproofing agents, flooring materials , useful for elastic fibers, etc.

EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples and Comparative Examples.

In addition, in the examples, the hydrolysis resistance of polycarbonate-based polyurethane is determined by
We conducted a hydrolysis acceleration test for 4 weeks in hot water at 00℃,
In the case of polyester polyurethane, a hydrolysis acceleration test was performed in hot water at 100°C for one week, and the viscosity of the polyurethane solution in a mixed solvent of dimethylformamide/toluene (weight ratio 7/3) was measured before and after the test. The retention rate of the logarithmic viscosity after the test relative to the logarithmic viscosity before the test was evaluated.

Regarding low-temperature flexibility, we made a υ test piece from a polyurethane film with a thickness of 0.2 m+ and used a direct-reading dynamic viscoelasticity measuring instrument Paopron Model DDV-z (manufactured by Toyo Saiki ■).
The evaluation was made by measuring Tα according to 11orhZ), and by coating the polyurethane solution on the artificial leather substrate, drying it, and measuring the bending resistance at -20°C. The bending resistance was measured using a bending tester with a stroke width (maximum: 3 CM, shortest: 1 cyx) and a bending frequency of 8,600 times/hour. If there is no change after 100,000 cycles or more, the mark is ○, if there is a slight scratch, the mark is △, and if the base is scratched to the extent that it is visible, the mark is x. A material with a low Tα and good low-temperature flexibility can achieve both low-temperature sinterability and amorphism.

EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples and Comparative Examples.

In addition, in the examples, the hydrolysis resistance of polyurethane is 60μ
A polyurethane film with a thickness of
A weekly hydrolysis acceleration test was conducted, and the polyurethane solution was dimethylformamide/toluene (
The viscosity of the mixed solvent solution (M ratio 7/3) was measured and evaluated based on the retention ratio of the logarithmic viscosity after the test to the logarithmic viscosity before the test.

Regarding low-temperature flexibility, test specimens were made from polyurethane film with a thickness of 0.2 mm, and a direct-reading dynamic viscoelasticity meter manufactured by Toyo Saiki ■, Paipron Model DDV-[(I
By measuring Tα by IOH2), a polyurethane solution was further applied and dried on the artificial leather base, and -
The evaluation was made by measuring the bending resistance at 20°C. The bending resistance is determined by the stroke width (3 cx at the longest, 1 cx at the shortest)
The test was conducted using a bending tester with a bending speed of 8,600 times/hour. If there is no change after 100,000 times or more, ○,
If it is slightly scratched, mark it as △, if it is damaged so much that the base is visible, mark it as ×.
It was shown as follows. A material with a low Tα and good low-temperature flexibility can achieve both low-temperature visibility and amorphization.

Further, the surface abrasion resistance was expressed by the amount of abrasion measured using a tapered abrasion tester (H-22, load 1000p, 1000 times) using a polyurethane film with a thickness of 1 mm. The compounds used are indicated using abbreviations, and the relationship between the abbreviations and compounds is as shown in Table 1.

Reference Example 1 (Production of polyester polyolefin) 16009 t of 2-methyl-1,8-octanediol and 1460 t of adipic acid (Molar ratio of 2-methyl-1,8-octanediol/adipic acid: 1.3/1 )
Esterification was carried out at a temperature of about 195° C. while passing nitrogen gas under normal pressure and distilling off condensed water. When the acid value of the polyester became about 1 or less, the degree of vacuum was gradually increased using a vacuum pump to complete the reaction.

In this way, polyester with a hydroxyl value of 56 and an acid value of 0.23 (
(hereinafter referred to as polyester) was obtained. This polyester is liquid at room temperature and has a viscosity of approximately 5000 at 25°C.
The centivoice molecular weight was approximately 2,000.

Reference Examples 2 to 11 The same procedure as Reference Example 1 was carried out except that the acid component and diol component shown in Table 2 were used, respectively, and the hydroxyl value was 5.
In Example 6, a polyester having an acid value and a molecular weight shown in Table 2 was obtained.

Reference example 12 (Manufacture of polycarbonate polyol) Under nitrogen flow, 2
A mixture of -methyl-1,8-octanediol 17309 and diphenyl carbonate 2140f was heated and diphenol was distilled off from the reaction system at 200°C.

The temperature was gradually increased to 210-220°C, and after most of the phenol had been distilled off, vacuum was applied, and the residual phenol was completely distilled off at 210-220°C under a vacuum of 6-10+ mHp. As a result, a liquid substance with a hydroxyl value of 56 was obtained.

The molecular weight is approximately 2,000. This polycarbonate is hereinafter referred to as polycarbonate A.

Reference Examples 13 to 16 A hydroxyl value of 56 and a hydroxyl value of about 2
A polycarbonate with a molecular weight of 0.000 was obtained.

Margin table below: 31 mol of polyester produced in Example 1 Reference Example], MDI (4,
1 mole of 4'-diphenylmethane diisocyanate) and 3 moles of BD (1,4-butanediol) as a chain extender were mixed in a mixed solvent of dimethyl formaldehyde and toluene (mixed weight ratio 7:3) at 70°C under a nitrogen gas stream. The reaction gave a polyurethane solution of 30% by weight and 1500 voids at 25°d. Various performances of the obtained polyurethane were investigated.

The results are shown in Table 4.

Examples 2 to 8 and Comparative Examples 1 to 3 5J! except that the polyesters shown in Table 4 were used in place of polyester A. A polyurethane solution was obtained in the same manner as in Example 1. Their viscosity at 25°C is 1
It was in the range of 200-20oO Pois. Table 4 shows the results of examining various performances of the obtained polyurethane.

Examples 9 to 11 and Comparative Examples 4 to 5 Polyurethane solutions were obtained in the same manner as in Example except that the polycarbonates shown in Table 4 were used instead of polyester/I/A. Their viscosity at 25°C is 1
It was in the range of 200 to 2000 poise. Table 4 shows the results of examining various performances of the obtained polyurethane.

Effects of the Invention on Lower Cis Margin By following the production method of the present invention, a novel polyurethane having excellent hydrolysis resistance, low-temperature properties, and abrasion resistance can be obtained.

Claims (4)

[Claims] (1) In the method of producing polyurethane from a polymer polyol and an organic polyisocyanate, a polymer polyol having a group represented by ▲ mathematical formula, chemical formula, table, etc. ▼ [I] in the molecule is used as the polyol. A manufacturing method for polyurethane characterized by: (2) A polymer polyol having a group represented by the general formula [I] in the molecule is obtained by reacting 2-methyl-1,8-octanediol or a mixed glycol containing the diol with a dicarboxylic acid. An average molecular weight of 500 to 30 obtained by reacting a polyester polyol or 2-methyl-1,8-octanediol or a mixed glycol containing the diol with a dicarbonate having an average molecular weight of 500 to 30,000.
,000 polycarbonate polyol. (3) The mixed glycol consists of 2-methyl-1,8-octanediol and an alkanediol represented by the general formula HO-(CH_2)-_nOH (in the formula, n represents an integer from 6 to 9) The manufacturing method according to claim 2. (4) Mixed glycol is 2-methyl-1,8-octanediol and an alkane represented by the general formula ▲ Numerical formula, chemical formula, table, etc. ▼ (However, in the formula, m represents an integer from 1 to 4) The manufacturing method according to claim 2, which comprises a diol.