JPH0330612B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel method for producing polyurethane, and in particular to a rigid polyurethane having a high heat distortion temperature.

Rigid polyurethane is broadly classified into non-foamed molded products and foamed molded products, and foamed molded products are further classified into high-foamed molded products and low-foamed molded products depending on the foaming rate. Non-foamed molded products and low-foamed molded products are used as engineering resins in various equipment parts and automobile parts, while highly foamed molded products are used as general-purpose resins that are useful in an extremely wide range of applications, such as being mainly used in insulation materials. ing.

Conventional rigid polyurethanes contain one or more polyfunctional aliphatic or aromatic polyol monomers, polyoxyalkylene polyols, especially polyoxypropylene polyols, or polyfunctional aliphatic or aromatic polyester polyols. A polyol component consisting of a mixture and a polyisocyanate component consisting of one or more of resinous or aromatic polyisocyanates or polyisothiocyanates are cured and molded in the presence of a catalyst, a blowing agent, etc.

However, these polyurethane molded products generally have poor heat resistance, and when heat distortion temperature (measured according to ASTM D-648) is used as a measure to evaluate heat resistance, conventional polyurethane molded products have a heat distortion temperature of 80 to 100 at most. ℃ was the limit, and it was difficult to exceed 100℃ with practical strength. On the other hand, heat resistance can be improved by introducing isocyanurate groups obtained by triplication of isocyanates.
At the same time, the resulting molded product becomes extremely brittle and cannot be put to practical use.

The purpose of this invention is to provide a polyurethane with high thermal stability, and in particular, to provide a polyurethane with a temperature of at least 110
The object of the present invention is to provide a new rigid polyurethane which has a high heat distortion temperature of .degree. C. or higher and has practical strength, especially impact resistance.

As a prior art, a method for producing a non-foaming rigid urethane resin using a 2 mole adduct of bisphenol A with ethylene oxide and a 2 mole adduct of propylene oxide with bisphenol A as one component of the polyhydroxy compound is disclosed in Tokko Sho. It is known as No. 55-17766. However, bisphenol A
The non-foamed rigid urethane resin using 2 mole ethylene oxide adduct of bisphenol A alone has a high melting point (mp110
°C), which has the disadvantage that the reaction with isocyanate compounds is too rapid and is substantially difficult to carry out, and non-foaming methods using propylene oxide adducts of bisphenol A alone Cured urethane resins have drawbacks in terms of workability, such as high viscosity, easy entrainment of air bubbles, and low strength when demolded.
This invention is a novel invention that improves the above-mentioned drawbacks.

The present invention is a method for producing polyurethane in which one or more polyol components having at least difunctional hydroxyl groups are reacted with one or more polyisocyanate components having at least difunctionality, wherein the polyol component has hydroxyl groups. Price: 200~
700 aromatic amine-based polyoxyalkylene polyol and 2,2-bis{4-
Using 20 to 45 parts by weight of a propylene oxide adduct of 2,2-bis(4-hydroxyphenyl)propane containing (2-hydroxypropoxy)phenyl}propane as one component, react at an isocyanate index of 100 to 180. The present invention relates to a method for producing a highly heat-resistant rigid polyurethane.

The hard polyurethane of the present invention can be used in various fields, and is particularly useful as various industrial parts that require heat resistance, such as sliding material parts or other coatings.

As the polyol component used in this invention,
Aromatic polyamine base polyoxyalkylene polyol and propylene oxide adduct of 2,2-bis(4-hydroxyphenyl)propane are used together to increase the average hydroxyl value of the polyol component to 200 to 200.
700, preferably 300 to 500, the impact strength of the polyurethane obtained was surprisingly contrary to expectations, and it was found that a synergistic effect of increasing the impact strength without almost reducing the high HDT was obtained. That is, the impact strength of the polyurethane using the above two types of polyol components in combination is superior to the impact strength of each polyurethane when the above two types of polyol components are used alone. The reason for this has not yet been fully elucidated, but considering that it has been extremely difficult to increase both HDT and impact strength with conventional hard polyurethanes, the effects of this invention are surprising. In addition, in the present invention, by using the PO adduct of bisphenol A and the aromatic amine-based polyol in combination, the
It has been found that not only HDT and impact strength can be obtained, but also workability, moldability, etc. can be effectively improved. The improvement in processability referred to here refers to the reduction in the viscosity of the polyol liquid due to the introduction of the aromatic amine-based polyol, and the improvement in so-called compatibility in which the polyol liquid and the polyisocyanate liquid mix well even at room temperature. Further, since the chemical reaction proceeds due to the moderate autocatalytic action of the aromatic tertiary amine, no catalyst is intentionally required. Therefore, since there is no need to add a catalyst to the polyol liquid, the storage stability of the polyol liquid is excellent.
Furthermore, improvement in moldability includes increasing the strength of the polyurethane molded product upon demolding due to the introduction of a primary network using at least a bifunctional aromatic amine-based polyol.

At least the above bifunctional hydroxyl value 200 to 700,
Preferably 300 to 500 aromatic amine-based polyoxyalkylene polyols are prepared by known methods such as aromatic monoamines such as aniline or 2,4- and 2,6-tolylene diamines (TDA) and so-called crude TDA, 4,4 '-diaminodiphenylmethane and one type of aromatic diamine and aromatic polyamine such as polymethylene polyphenylene polyamine obtained by condensation of aniline and formalin, ortho-, meta- or para-phenylene diamine, meta- or para-xylylene diamine, or More than that, bisphenol A-PO is added to a polyol obtained by adding one or more alkylene oxides such as propylene oxide and ethylene oxide, and in which substantially no free primary or secondary amine remains. When used in combination with a polyol, it is particularly preferable that the average hydroxyl value of the polyol component is 300 to 500. In addition, the tertiary amine concentration of this combined polyol is preferably 3 meq/g or less, and is 0.2 to
A range of 1.5 meq/g is particularly preferred. Within these ranges, the above-mentioned synergistic effect due to combined use is particularly remarkable.

The above-mentioned aromatic amine-based polyols are synthesized at the stage of synthesis to reduce viscosity and improve processability
In addition to aromatic amines, the following aliphatic glycols and the like can be used as coinitiators. For example, polyfunctional aliphatic glycols such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, glycerin, trimethylolpropane, glucose, sorbitol, and cyutatose, aliphatic amines and fats such as ethanolamine, diethanolamine, triethanolamine, and ethylenediamine. Examples include group alkanolamines, and these co-initiators are preferably used in an equimolar or less amount relative to the aromatic amine. In addition, in this invention, 2,2-bis{4-(2-hydroxypropoxy)phenyl}propane having the following structure is used in combination with an aromatic polyamine-based polyoxyalkylene polyol as a polyol component. 2-
By using a propylene oxide (hereinafter referred to as PO) adduct of bisphenol A), we succeeded in obtaining a rigid polyurethane with excellent heat resistance.

That is, in this invention, since the PO adduct of bisphenol A was used as the polyol component,
Polyurethane obtained by reacting with polyisocyanate has a high concentration of aromatic rings in the molecular chain and has a rigid molecular structure, so it has a high glass transition point. Therefore, it has excellent thermal stability, and has a low heat distortion temperature (hereinafter referred to as HDT).
It also exhibits the characteristic of being high in

The bisphenol A-PO adduct of the present invention can be obtained by reacting 1 mole of bisphenol A with 2 moles or more of PO by a known method. That is, the above adduct is 2,2-bis{4(2-
Hydroxypropoxy) phenyl}propane 1
The content is usually about 40% by weight or more, preferably about 80% by weight or more.
As other components, adducts containing 3 moles or more of PO are usually about 60% by weight per 1 mole of bisphenol A.
It can preferably be contained in an amount of about 20% by weight or less. In addition, as another component, it has one or two primary terminal hydroxyl groups, is produced as a by-product during the addition reaction of 2 or 3 moles or more of bisphenol A and PO, and can be included in the polyol component in any proportion. can.

However, for example, bisphenol A and bisphenol A having unreacted phenolic hydroxyl groups
The content of adducts of 1 mole of PO, etc. must be 1% by weight or less.

If the adduct containing 2 moles of PO to 1 mole of bisphenol A is less than 40% by weight, the concentration of the skeleton of bisphenol A as a polyol component decreases, resulting in a decrease in the heat resistance of the resulting polyurethane.

As the polyisocyanate component of this invention, at least two of various types in the field of polyurethane production are used.
Known functional aliphatic, cycloaliphatic and aromatic polyisocyanates can be used, among which aromatic polyisocyanates are particularly preferred. For example, 4,4'-diphenylmethane diisocyanate (MDI) and carbodiimide-modified MDI (e.g. Nippon Polyurethane Co., Ltd. MTL), polymethylene polyphenyl isocyanate (PAPI), polymeric polyisocyanate (e.g. Sumitomo Bayer Urethane)
44V), 2,4- and 2,6-tolylene diisocyanate (TDI), orthotoluidine diisocyanate (TODI), naphthylene diisocyanate (MDI), xylylene diisocyanate (XDI), and the like are preferably used.

This invention uses aromatic amine-based polyols from 55 to
By using 20 to 45 parts by weight of PO adduct of bisphenol A and polyisocyanate as a polyol component, the polyurethane obtained by combining it with polyisocyanate is characterized by having a high HDT. It has processability and moldability, but
In addition to these polyol components, another at least difunctional polyol having a hydroxyl value of 50 to 1830 can be used in an amount of 5 to 25 parts by weight based on the total polyol component, which improves processability such as reducing the viscosity of the polyol component. It has the effect of improving moldability. In particular, the reason why the aromatic amine-based polyol was set at 55 to 80 parts by weight is as follows.
Ability to reduce viscosity during molding. Good compatibility with isocyanate. High initial strength after molding. If it is less than 55%, these effects are insufficient, and if it is more than 80%, the curing speed becomes too fast and moldability is poor. Similarly, the reason why the PO adduct polyol component of bisphenol A is set at 20 to 45 parts by weight is that it does not lower Tg and has excellent properties (for example, impact resistance). If it is less than 20%, the properties will not be effective, and if it is more than 45%, problems will arise in viscosity, compatibility with isocyanate, and initial strength (strength after demolding).
Specific examples of the at least difunctional polyol having a hydroxyl value of 50 to 1830 include the following polyols.

(a) An aromatic polyol having a hydroxyl value of 50 to 850 and having at least difunctional hydroxyl groups.

(a) Hydroquinone, pyrogallol, 4,4'-
A polyol with a hydroxyl value of 250 to 600 obtained by adding an alkylene oxide such as propylene oxide or ethylene oxide to a monocyclic or polycyclic aromatic compound having at least two hydroxyl groups such as isopropridenphenol, (b) phthalic acid, Hydroxyl value obtained by adding alkylene oxides such as propylene oxide and ethylene oxide to aromatic polybasic acids such as isophthalic acid, terephthalic acid, and trimellitic acid.
800 to 500 polyol, (c) metaxylylene glycol, paraxylylene glycol, (d) aromatic dicarboxylic acid such as phthalic acid, isophthalic acid, terephthalic acid or its anhydride or lower alcohol ester thereof, and/or adipine Acid, aliphatic dicarboxylic acid such as succinic acid is used as the acid component, aliphatic polyol such as ethylene glycol, 1,4-butylene glycol, trimethylolpropane, 1,4-cyclohexanediol, 1,
4-cyclohexanedimethanol, β, β,
β',β'-tetramethyl-2,4,8,10-tetraoxaspiro(5,5)-undecane-
Alicyclic polyols such as 3,9-diethanol or the above (a), (b), (c)
A polyester polyol with a hydroxyl value of 50 to 450 whose polyol component is a polyol of It is preferable to

(b) Polyfunctional aliphatic glycol with a hydroxyl value of 800 to 1830.

Examples include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, glycerin, and triethanolamine, which can be used in combination in an amount of 10% by weight or less based on the total polyol.

(c) A polyfunctional aliphatic polyol with a hydroxyl value of 300 to 800.

For example, a polyol in which one or more alkylene oxides such as propylene oxide and ethylene oxide are added to one or more of sucrose, sorbitol, glucose, pentaerythritol, trimethylolpropane, glycerin, ethylenediamine, diethanolamine, water, etc. It is preferable to use them together in an amount of 50% by weight or less based on the total polyol.

The polyols listed above are particularly preferred, and at least other difunctional polyols with a hydroxyl value of 50 to 1830 are added to the total polyols at a ratio of 50 to 1830.
They can be used in combination within a range not exceeding % by weight.

Prior to the reaction with isocyanates, these polyols have a moisture content of 0.50% or less, preferably
It is necessary to keep it below 0.02%. Also, the polyisocyanates should be sufficiently degassed in advance. If these are neglected, unnecessary foaming will occur during the curing reaction. However, this is of course not the case when obtaining a foam.

The polyol component and the polyisocyanate component can be reacted by a one-shot method or a prepolymer method. The reaction between polyol and polyisocyanate is used as an isocyanate index.
It is appropriate to carry out the treatment in the range of 100 to 180, preferably 105 to 160; outside this range, heat resistance decreases regardless of whether the isocyanate index becomes smaller or larger. The cause of this is not clear, but it is presumed that it is due to a decrease in the substantial molecular weight of the polymer. Although a catalyst is not particularly required in this invention, tertiary amines such as triethylene diamine, organometallic compounds such as dibutyltin dilaurate, etc. It is also possible to use known catalysts. However, isocyanate trimerization catalysts that produce isocyanurate rings are not preferred. It is also possible to obtain an inorganic filler-containing rigid polyurethane by preliminarily mixing the inorganic filler with polyol or polyisocyanate. Examples of inorganic fillers include glass fibers such as milled glass fibers and chopped strand glass fibers, graphite, silicon carbide, aluminum oxide, and molybdenum disulfide.
Effective in improving friction coefficient, wear resistance, etc. In the present invention, it is also possible to form a foam by using water, a halogenated hydrocarbon such as trifluorotrichloroethane, or an organic blowing agent such as azobisisobutyronitrile.

In this invention, the curing reaction can be carried out, for example, as follows. First, adjust the liquid temperature of the compound to room temperature.
The mold temperature is set at 120°C, and the temperature of the casting mold is set at 50 to 120°C, and the mold is poured, hardened, and demolded. Although the cured molded product of this invention has a higher HDT than conventional polyurethane molded products as it is, properties such as impact strength can be improved by further heat-treating it at a temperature of 140 to 180°C. . The heat treatment can be performed in an inert gas atmosphere such as air or nitrogen.

This invention will be explained below with reference to Examples.

Example 1 OH value obtained by addition reaction of 5.6 moles of propylene oxide and 2.6 moles of ethylene oxide to 1 mole of 2,4-tolylene diamine (TDA)
55 g (0.393 equivalents) of TDA-based polyol of 400 and propylene oxide adduct of bisphenol A [manufactured by Toho Chiba Chemical Co., Ltd., "Bisol-2P" (approx. 93% of 2 mole adduct of PO by gas chromatographic analysis,
Contains approximately 7% of the 3 molar adduct of PO. OH value 316)
Heat to 100℃ and dehydrate under reduced pressure to reduce moisture content to 0.015%
I made it. 50 g of this polyol (0.253 equivalent)
℃, 100 g of this blended polyol and 113 g (0.775 equivalents) of carbodiimide-modified MDI (Nippon Polyurethane Co., Ltd., "Coronate MTL" NCO content 28.8%) were stirred with a propeller for 40 seconds in a beaker, and then decomposed in a vacuum desiccator for 1 minute. I molded it. This mixture was immediately heated to 90℃.Inner dimensions: 130mm x 180mm
Pour into a 6mm assembled glass mold,
After reacting for 30 minutes in an air constant temperature bath at 100°C, the cured product was taken out from the mold. During this time, no bubbles were observed. Next, heat treatment was performed for 2 hours in a constant air bath at 160°C to obtain a non-foamed, tough, rigid polyurethane.

Heat deformation temperature (load 18.6Kg/cm ² ) 120℃ Flexural modulus 24700Kg/cm ² Izot impact value (with notch) 5.0Kg. cm/cm The test method was as follows (the same applies below).

Heat deformation temperature [ASTM-D684, load 18.6Kg/cm ² ] Flexural modulus [ASTM-D-790] Izot impact value [ASTM-D256 with notch] Example 2 The amount of polyisocyanate in Example 1 is 151g
(1.022 equivalents) and the isocyanate index was increased to 160, but in the same manner as in Example 1, a non-foamed, tough, rigid polyurethane was obtained.

Heat deformation temperature (load 18.6Kg/cm ² ) 131℃ Flexural modulus 25100Kg/cm ² Izot impact value (with notch) 4.8Kg. cm/cm Example 3 800 mesh carborundum (silicon carbide,
Hanai Chemicals) was dried at 110℃ overnight, then mixed with 100g of "Coronate MTL" and 50g of carbon dam, stirred in a flask under reduced pressure at 80℃ for 1 hour, and then returned to normal pressure with nitrogen gas. The liquid temperature was set to 32°C. Using 150 g of this polyisocyanate solution containing carborundum and 100 g of the mixed polyol used in Example 1 at 30°C, a reaction was carried out in the same manner as in Example 1 to obtain a non-foamed rigid polyurethane containing 20% by weight of carborundum and a specific gravity of 1.35. .

Heat deformation temperature (load 18.6Kg/cm ² ) 121℃ Flexural modulus 35600Kg/cm ² Izot impact value (with notch) 2.0Kg. cm/cm Example 4 0.04 g of dibutyltin dilaurate and 20 g of monochlorotrifluoromethane (Freon 11) were mixed with 200 g of the mixed polyol used in Example 1, and the liquid temperature was brought to 80°C.

Add 208g of polymeric polyisocyanate "Sumigiur 44V-20" (Sumitomo Bayer Urethane GmbH, NCO content 31.0%) at 30°C to this, stir vigorously for 15 seconds with a high-speed lab mixer, and immediately place it in an aluminum tube with an inner diameter of 200mm at 80°C. The required amount was poured into a 200 mm x 10 mm mold, the lid was closed, and the mixture was foamed and cured. After 30 minutes, the mold was demolded and then heat treated in an air constant temperature bath at 140°C for 2 hours to obtain a rigid polyurethane foam with a specific gravity of 0.32.

Heat distortion temperature (load 4.6Kg/cm ² ) 107℃ Bending modulus 3500Kg/cm ² Bending strength 102Kg/cm ² Izot impact value (without notch)
2.0Kg. cm/cm Example 5 A rigid polyurethane foam having a specific gravity of 0.71 was produced in the same manner as in Example 4.

Heat deformation temperature (load 4.6Kg/cm ² ) 120℃ Bending modulus 12400Kg/cm ² Bending strength 573Kg/cm ² Izot impact value (without notch)
4.8Kg. cm/cm Comparative Example 1 Trimethylolpropane-based polyoxypropylene polyol "T-400" (Adeka, OH value
391) 100g (0.697 equivalent) and Sumidyur 44V−
104 g (0.768 equivalents) of 20 was reacted in the same manner as in Example 2 (but without heat treatment) to obtain a non-foamed rigid polyurethane.

Heat deformation temperature (load 18.6Kg/cm ² ) 76℃ Flexural modulus 23800Kg/cm ² Izot impact value (with notch) 3.0Kg. cm/cm Comparative Example 2 100 g of the TDA-based polyol used in Example 2 and 109 g of Coronate MTL were reacted in the same manner as in Example 2 to obtain a non-foamed rigid polyurethane.

Heat deformation temperature (load 18.6Kg/cm ² ) 102℃ Flexural modulus 25100Kg/cm ² Izot impact value (with notch) 3.2Kg. cm/cm Comparative Example 3 100g of TDA-based polyol used in Example 2,
A polyol component prepared by mixing 100 g of the polyol used in Comparative Example 1, 0.04 g of dibutyltin dilaurate, and 20 g of monochlorotrifluoromethane, and 220 g of Sumidyur 44V-20 were used in the same manner as in Example 5 (but without heat treatment) to obtain a specific gravity of 0.50. A rigid polyurethane foam was obtained.

Heat distortion temperature (load 4.6Kg/cm ² ) 83℃ Bending modulus 6000Kg/cm ² Bending strength 184Kg/cm ² Izot impact value (without notch)
2.8Kg. cm/cm

Claims (1)

[Scope of Claims] 1. A method for producing polyurethane, comprising reacting one or more polyol components having at least difunctional hydroxyl groups with one or more polyisocyanate components having at least difunctionality, comprising:
As the polyol component, an aromatic amine-based polyoxyalkylene polyol with a hydroxyl value of 200 to 700 is used.
55 to 8 parts by weight and 20 to 45 parts by weight of a propylene oxide adduct of 2,2-bis(4-hydroxyphenyl)propane containing 2,2-bis{4-2-hydroxypropoxy)phenyl}propane as one component. 1. A method for producing a highly heat-resistant rigid polyurethane, characterized in that the reaction is carried out using parts by weight and an isocyanate index in the range of 100 to 180. 2. The method for producing a highly heat-resistant rigid polyurethane according to claim 1, wherein 5 to 25 parts by weight of a polyfunctional aliphatic polyol having a hydroxyl value of 30 to 800 is used in combination with the polyol component. 3 The average hydroxyl value of the polyol component is 200 to 700
The method for producing a highly heat-resistant rigid polyurethane according to claim 1, wherein an aromatic polyisocyanate is used as the polyisocyanate.