JPH0471089B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a method for producing a polyisocyanurate resin having excellent heat resistance and impact resistance. (Prior Art) Conventionally, polyisocyanurate resins obtained by reacting organic polyisocyanates with polyether polyols in the presence of trimerization catalysts are known to have excellent heat resistance, but impact resistance is poor. There are some disadvantages. (Object of the Invention) The present inventors have conducted repeated studies to find a method for producing a polyisocyanurate resin having excellent heat resistance and impact resistance, and as a result, they have arrived at the present invention. (Structure of the Invention) That is, the present invention provides a method for producing a polyisocyanurate resin from an organic polyisocyanate and a polyol in the presence of a trimerization catalyst. Use the following ring-opening polymerized polyether polyol of tetrahydrofuran or a chipped or balanced polyether polyol with tetrahydrofuran or ethylene oxide added to the terminal, (2) with an isocyanate index of 200 to 5500, (3) silicone This is a method for producing polyisocyanurate resin, which is characterized by reacting in the presence of an antifoaming agent and (4) heat-treating at a temperature of 60 to 300°C. In the present invention, at least a part of the polyol is a di- to trifunctional tetrahydrofuran ring-opening polymerized polyether polyol having an OH value of 130 or less, preferably 100 or less, and more preferably 60 or less, or a polyether polyol having tetrahydrofuran or ethylene oxide added to the terminal. A type of chipped or balanced polyether polyol is used. This polyether polyol is a compound having a structure in which an alkylene oxide is added to a polyfunctional compound containing an active hydrogen atom, such as a polyhydric alcohol, a polyhydric phenol, or a polycarboxylic acid. The above-mentioned polyhydric alcohols include dihydric alcohols such as ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, diethylene glycol, and neopentyl glycol, and glycerin, trimethylolpropane, pentaerythritol, sorbitol, and Trivalent or higher polyhydric alcohols such as sugar; polyhydric phenols include polyhydric phenols such as pyrogallol and hydroquinone, and bisphenols such as bisphenol A; polycarboxylic acids include succinic acid, adipic acid, etc. aliphatic polycarboxylic acids, phthalic acids,
Examples include aromatic polycarboxylic acids such as terephthalic acid and trimellitic acid. Two or more kinds of the above-mentioned active hydrogen atom-containing compounds can also be used. Examples of the alkylene oxide to be added to the active hydrogen atom-containing compound include ethylene oxide, propylene oxide, butylene oxide, tetrahydrofuran, styrene oxide, and epichlorohydrin. The alkylene oxides may be used alone or in combination of two or more, and in the latter case, block addition, random addition, or a mixture of both may be used. Preferred among these alkylene oxides are tetrahydrofuran, propylene oxide and/or ethylene oxide. From the viewpoint of reaction, particularly preferred is a combination system of propylene oxide and ethylene oxide (usually 30:70 to 95:5 in weight ratio, especially 70:
30-90:10) and a combination system of tetrahydrofuran and ethylene oxide (usually 95:5-30:
70, especially 90:10 to 50:50). Addition of alkylene oxide can be carried out in the usual manner, either without catalyst or in the presence of a catalyst (alkaline catalyst, amine catalyst, acidic catalyst) (particularly in the latter stages of alkylene oxide addition) at normal pressure or under pressure. It is done under pressure. The above-mentioned polyether polyol used in the present invention has a terminal primary OH, and usually contains 100% to 20% of tetrahydrofuran (hereinafter abbreviated as THF) or ethylene oxide (hereinafter abbreviated as EO) at the terminal.
(Weight) Added items (chip type, balanced type)
It is. By using a polyether polyol with primary OH terminals, it has fast demoldability and high heat resistance.
A polyisocyanurate resin with excellent impact resistance is obtained. The polyether polyol can be used in combination with other polymer polyols if necessary. Examples of other polymeric polyols include polyester polyols, such as condensed polyester polyols obtained by reacting low-molecular polyols with dicarboxylic acids, and polyester polyols obtained by ring-opening polymerization of lactones. Examples of the low-molecular polyols include diols such as ethylene glycol, propylene glycol, 1,6-hexanediol, diethylene glycol, neopentyl glycol, bis(hydroxymethyl)cyclohexane, and bis(hydroxyethyl)benzene; trimethylolpropane, glycerin, and the like; A mixture of Examples of dicarboxylic acids include succinic acid, glutaric acid, adipic acid, sebacic acid, maleic acid, fumaric acid, phthalic acid, terephthalic acid, dimer acid, and mixtures thereof. Examples of the lactone include ε-caprolactone. The OH value of the polyester polyol is usually 130 or less, preferably 100 or less, and more preferably 60 or less. The ratio (weight ratio) of polyether polyol and other polymer polyol (polyester polyol) can be varied, for example, from 20:80 to 100:0, preferably
The ratio is 50:50 to 100:0. As the organic polyisocyanate used in the present invention, those conventionally used in the production of polyurethane can be used. Specific examples of these include compounds described in JP-A-57-2322 and the like. Among these, aromatic diisocyanates are preferred, and TDI and MDI are particularly preferred. These polyisocyanates are produced by reacting crude polyisocyanates such as crude TDI, crude MDI, modified polyisocyanates such as liquefied MDI (carbodiimide modification, trihydrocarbyl phosphate modification, etc.) or excess polyisocyanates (TDI, MDI, etc.) with polyols. It can also be used as a free isocyanate-containing prepolymer obtained by Examples of the polyol used in the production of the prepolymer include polyols having an equivalent weight of 30 to 5,000, such as glycols such as ethylene glycol and propylene glycol, high-functional polyols such as trimethylolpropane and pentaerythritol, and alkylene oxide adducts thereof. Moreover, polyester polyol can also be used in combination. Among these, the preferable one is functional group 2
~3. The content of free isocyanate groups in the above-mentioned modified polyisocyanates and prepolymers is usually 10 to 30%, preferably 15 to 30%, particularly preferably around 25%. As antifoaming agents that can be used in the present invention, silicone-based antifoaming agents such as those of the general formula (R is H, methyl or/and phenyl group,
n is a number from 100 to 10,000), silicone oils (polydimethylsiloxane, polymethylphenylsiloxane, etc.), tri- or tetra-alkylsilanes, silicone alcohols, and the like. The viscosity of silicone oil is usually 500~
10,000 centipoise (25℃). For more information on silicone oils, see Chemistry and Technology of Silicones (Walter Knoll, Academic Press, 1968),
“Kirkuosmar: Encyclopedia of Chemical Technology” (2nd edition) Volume 18
It is described on pages 221-260. The amount of antifoaming agent added is usually 0.001 parts per 100 parts of polyisocyanurate resin.
-10%, preferably 0.01-5%. Addition of this type of antifoam agent helps prevent loss of impact resistance. As the trimerization catalyst used in the present invention, known ones can be used. Specifically, metal salts of carboxylic acids, such as sodium acetate, lead octylate,
zinc octylate, cobalt naphthenate, etc.; alkoxides and phenoxides of alkali and alkaline earth metals, such as sodium methoxide,
Sodium phenoxide etc.; tertiary amines such as triethylamine, triethylenediamine,
N-methylmorpholine, (dimethylaminomethyl)
Phenol, pyridine, etc.; Quaternary ammonium bases, such as tetraethylammonium hydroxide; Imidazoles, such as imidazole, 2-ethyl-4-methylimidazole, etc.; Organometallic compounds such as tin and antimony, such as tetraphenyls and tributyl antimony oxide. Among these, preferred is a combination system of a metal salt of carboxylic acid and a tertiary amine. The amount of trimerization catalyst used is usually 0.01 to 10 parts per 100 parts of organic polyisocyanate.
The amount is preferably 0.05 to 5 parts. In the present invention, the reaction can be carried out in the presence of other catalysts (tertiary amines, organic tin compounds, organic lead compounds, etc.) and other auxiliary agents, if necessary. Pigment if necessary,
Fillers can also be added. In producing the polyisocyanurate resin in the present invention, the isocyanate index is usually 200 to 200.
5500 preferably 300-5000. When the isocyanate index is high, heat resistance is good but impact resistance is poor. On the other hand, when the isocyanate index is low, the performance is the opposite. In producing the polyisocyanurate resin in the present invention, the heat treatment temperature is usually 60 to 300°C, preferably 80 to 280°C, more preferably 130 to 250°C. The heat treatment conditions have a great influence on the completion of the resin reaction and the microphase structure. This makes it possible to produce a heat-resistant and impact-resistant polyisocyanurate resin. The heat treatment time is usually 10 minutes to 10 hours, preferably 30 minutes to 8 hours. Heat treatment at low temperatures will result in insufficient heat resistance, and heat treatment at temperatures above 300°C will cause thermal decomposition of the resin, which is not preferred. The resin production method according to the present invention may be the same as the conventional method, and either the one-shot method or the prepolymer method can be applied. As a method for producing the polyisocyanurate resin of the present invention, molding by vacuum degassing molding method and RIM method is useful, but other methods can also be applied. (Effects of the Invention) The polyisocyanurate resin obtained by the present invention has superior moldability compared to conventional polyisocyanurate resins, and also has excellent heat and impact resistance. Due to the excellent heat and shock resistance of the resin obtained by the present invention, it is used in various fields of application, such as electrical products such as switch covers, power distribution box lamps and last accessories, and battery boxes, audio products such as speaker boxes, and automobiles. It is extremely useful as aircraft parts such as air filter boxes, ignition distributors, heaters, and their boxes. (Example) The present invention will be explained below with reference to Examples, but the present invention is not limited thereto. The measurement method is as follows: Heat distortion temperature (load 18.6Kgf/cm ² , according to JISK7207) Impact strength (IZOT, with notch, according to JISK7110) Example 1 Propylene oxide (hereinafter referred to as PO) in glycerin
) Next, a silicone antifoaming agent was added to 100 parts of a polyether polyol with an OH value of 28 obtained by adding 10% by weight of EO to the total amount of polyether polyol.
Sumidyur PC (NCO%) is used as an MDI polyisocyanate. 26%, manufactured by Sumitomo Bayer Urethane)
Add 100 parts (isocyanate index 1240), stir for 30 seconds, and defoam under reduced pressure. Pour into a mold preheated to 50-60°C, cure in an oven at 60°C for 5 minutes, and remove from the mold. Thereafter, heat treatment is performed in an oven at 100°C for 1 hour. A resin having the following properties was obtained. Heat deformation temperature 125℃ Impact strength 11.4Kg・cm/cm Example 2 100 parts of polytetramethylene ether glycol having a molecular weight of 3000 and having an OH group at the terminal obtained by ring-opening polymerization of THF was added to polycarboxylate as an isocyanurate catalyst. Add 0.1 part of 42 (manufactured by Sunabott Co., Ltd.) and 0.1 part of a silicone antifoaming agent, and bring the temperature of the solution to 40°C.
150 parts of the MDI polyisocyanate used in Example 1 was added to a mixture heated to 20°C and stirred for 30 seconds. After defoaming under reduced pressure, the mixture is poured into a mold preheated to 50-60°C, cured in an oven at 60°C for 5 minutes, removed from the mold, and heat-treated at 100°C for 3 hours. The properties of the obtained resin were as follows. Heat deformation temperature 130℃ Impact strength 6.3Kg・cm/cm Example 3 Using the raw materials shown in Example 1, preheating temperature 50~
The influence of heat treatment conditions was investigated for the resin that was poured into a mold at 60°C, cured at 60°C for 5 minutes, and then removed from the mold. A list of results is shown below.

[Table] Example 4 Instead of 100 parts of polytetramethylene ether glycol in Example 2, propylene oxide was added to propylene glycol so that the molecular weight was 2000, ethylene oxide was added in an amount that gave a molecular weight of 2200, and then the molecular weight A polyisocyanurate resin was obtained by processing in the same manner as in Example 2 using 100 parts of a polyether polyol obtained by adding propylene oxide to a molecular weight of 2,500 and ethylene oxide to a molecular weight of 3,000. The performance of this resin was as follows: heat distortion temperature: 132°C; impact strength: 8.5 kg·cm/cm. Reference Example 1 To 100 parts of a polyether polyol with a molecular weight of 600 obtained by adding PO to propylene glycol, 0.1 part of Polycat 42 and 0.1 part of a silicone antifoaming agent were added, and after uniformly mixing, the temperature was adjusted to 20°C. On the other hand, it was mixed with 400 parts of the same isocyanate as in Example 1 whose temperature was controlled at 20°C (isocyanate index 734), poured into a mold preheated to 60°C, cured at 60°C for 5 minutes, and then demolded.
Heat treatment is performed at 100°C for 1 hour. As for the performance, as shown below, the heat distortion temperature is good, but the impact resistance is extremely poor. Heat distortion temperature 103℃ Impact strength 1.4Kg・cm/cm

Claims (1)

[Claims] 1. A method for producing a polyisocyanurate resin by reacting an organic polyisocyanate and a polyol in the presence of a trimerization catalyst, comprising: (1) at least a portion of the polyol having a difunctional to trifunctional OH value; Use a ring-opening polymerized polyether polyol of tetrahydrofuran of 130 or less, or a chipped or balanced polyether polyol with tetrahydrofuran or ethylene oxide added to the terminal, (2) an isocyanate index of 200 to 5500, (3) A method for producing a polyisocyanurate resin, which comprises reacting in the presence of a silicone antifoaming agent, and (4) heat-treating at a temperature of 60 to 300°C.