JPS6360773B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a method for producing a rigid polyurethane foam by a one-shot method using a new polyol component, which has low thermal conductivity, low flyability, and dimensional stability at low temperatures. This relates to a hard urethane foam with excellent properties. [Prior Art] Rigid urethane foam is widely used as insulation material for refrigerators and other insulation materials for keeping heat and cold. In response to the recent energy and resource saving era, efforts are being made to reduce power consumption in refrigerators and the like while maintaining their traditional shapes as much as possible. For this reason, the rigid polyurethane foam used as a heat insulator needs to have better heat insulating properties, that is, it has a higher thermal conductivity.
0.0140Kcal/m・h℃ or less is required. In order to lower the thermal conductivity, it was necessary to make the bubbles in the rigid urethane foam smaller. [Problems to be Solved by the Invention] However, in the past, when attempting to make the bubbles of rigid urethane foam finer, the physical properties of the foam, such as flyability, low-temperature dimensional stability, and well pressure, deteriorated significantly. At present, a hard urethane foam that balances these characteristics has not been put into practical use. Currently, flyability is achieved with a 35mm thick panel form and a density of 29-30Kg/ ^m3 .
The limits were 20% or less, a low-temperature dimensional change rate of -3% or less, and a thermal conductivity of 0.0140 Kcal/m·h°C or more. In order to achieve a good balance among these factors, it is important to make full use of the materials used for rigid urethane foam: polyols, catalysts, foaming agents, blowing agents, and isocyanates. Among these, the polyol component plays an extremely large role. Typical polyols include seurose, sorbitol, ethylenediamine, triethanolamine, propylene glycol, etc. as initiators.
Some of these have added alkylene oxides such as ethylene and propylene. These are mixed and used in various proportions. However, with these common polyols, no matter how good the catalyst, foam stabilizer, and blowing agent isocyanate are, the above-mentioned drawbacks cannot be covered, and it has become necessary to develop a new polyol. It is an object of the present invention to provide a rigid polyurethane foam that has lower thermal conductivity than conventional foams at low density, and also has low dimensional stability and flyability. [Means for Solving the Problems] The above object is to provide a method for producing a rigid polyurethane foam by reacting a polyol component and an isocyanate component in the presence of a reaction catalyst, a blowing agent, and a foam stabilizer, in which the polyol component is
It consists of a mixture of the following (i) to (iv) with an OH value of 440 to 480. (i) Adipic acid polyester 14-18% by weight, (ii) Phthalic anhydride polyester 9-5% by weight, (iii) Tolylene diamine polyether 60-55% by weight (iv) Pentaerythritol polyether 17 ~
22% by weight, achieved by manufacturing a rigid polyurethane foam. [Function] The above polyol component is made by mixing tolylene diamine polyether with polyester, especially adipic acid polyester and phthalic anhydride polyester at the above mixing ratio, to reduce the thermal conductivity and make the pentaerythritol polyester By mixing polyether at the above mixing ratio, the increase in viscosity due to the mixing of the polyester is suppressed, fluidity is improved, and low-temperature dimensional stability is improved. In addition, the OH value of the above mixed polyol component is 440 to 480.
In this range, the above-mentioned low-temperature dimensional stability and flyability can be achieved at the same time. [Example] The present invention will be specifically explained based on Examples.
However, the present invention is not limited to the following examples. For example, the types and amounts of polyol components, polyfunctional isocyanate components, catalysts, foam stabilizers, blowing agents, and other additives may be used. In addition, the foam stock solution preparation method and foaming conditions, such as wall temperature, etc., can be changed as desired. Comparative Examples 1 to 13, Examples 1 to 12 Using the combinations shown in Table 1 as polyol components
Cooled MDI was used as the polyfunctional isocyanate component in accordance with the OH value of approximately 460. The blending ratio of polyol component and polyfunctional isocyanate component is
NCO/OH=1.10. The catalyst used was 2.5 parts of a mixture of 75% tetramethylhexamethylene diamine (Kaorizer No. 1, manufactured by Kao Soap) and 25% pentamethyldiethylenetriamine (PMDETA, manufactured by Kao Soap), and the foam stabilizer was a silicone block. 2 parts of polymer (L-5350, manufactured by Nippon Unicar), blowing agent is lower fluorinated hydrocarbon (trichlorofluoromethane, R-11, manufactured by Asahi Glass)
48 parts and 1.5 parts of water were used. At this time, the reaction rate is 8 to 10 for cream time.
The sample for physical properties of the form is a panel form of 400 mm x 600 mm x 35 mm. The low temperature dimensional change rate is -20℃×
This is the rate of dimensional change in the thickness direction after 24 hours, and flyability was determined according to the ASTM-C-421-61 method. Thermal conductivity was also measured using Anacon Model 88 (flat plate comparison method) as a panel form sample. From the physical properties shown in Table 1, the polyol components are 60 to 55% by weight of tolylene diamine polyether, 14 to 18% by weight of adipic acid polyester, 9 to 5% by weight of phthalic anhydride polyester, and 17% by weight of pentaerythritol polyether. It can be seen that the combination of ~22% by weight has good low temperature dimensional change rate and flyability, and low thermal conductivity. Further, if it deviates from these ranges, the balance of any one of the low-temperature dimensional change rate, flyability, and thermal conductivity will collapse, making it impossible to achieve the purpose. As mentioned above, the use of polyester in a rigid polyurethane foam has not been done in the past, and the present inventors have developed a method for manufacturing a rigid polyurethane foam using polyester, which has good low-temperature dimensional stability,
They discovered that it is possible to create a rigid polyurethane foam with excellent flyability. The above polyol components are specifically shown below. Tolylene diamine polyether is produced by adding propylene oxide and ethylene oxide to tolylene diamine to increase the OH value from 480 to 530 and the viscosity from 7,000 to 7,000.
It is a polyether polyol adjusted to 10,000 CPS/25℃. Adipic acid-based polyester is produced by reacting adipic acid with diethylene glycol and trimethylolpropane to increase the OH value to 430-480 and the viscosity to 4000-4000.
It is a polyester polyol adjusted to 4800CPS/25℃. Phthalic anhydride polyester is produced by reacting phthalic anhydride with diethylene glycol and trimethylolpropane to increase the OH value to 440-490 and the viscosity.
It is a polyester polyol adjusted to 4800-5600 CPS/25°C. Pentaerythritol-based polyether is made by adding propylene oxide and ethylene oxide to pentaerythritol to increase the OH value from 380 to
420, a polyether polyol with a viscosity adjusted to 1500-2500 CPS/25°C. Comparative Examples 14-15, Examples 13-15 Next, using Example 3, the optimum OH value was investigated. The method of Example 3 was followed except for changing the OH value. The results are shown in Table 2, and the OH value
It can be seen that the physical properties suitable for the purpose of the present invention are maintained in a well-balanced manner within the range of 440 to 480. Comparative Examples 16-17, Examples 16-18 Next, the optimum amount of water to be added was investigated (relative to polyol). The method of Example 3 was followed except for examining the amount of water added. In order to keep the density conditions as constant as possible, water = 1.7 trichlorofluoromethane = 46, water = 1.3 trichlorofluoromethane = 50,
Water = 1.0 trichlorofluoromethane = 53, water = 0.8 trichlorofluoromethane = 55. The results are shown in Table 3, and it can be seen that the physical properties suitable for the purpose of the present invention are maintained in a well-balanced manner when the amount of water added is in the range of 1.0 to 1.5. Originally, water generates carbon dioxide gas by reaction with isocyanate and does not have a very good effect on thermal conductivity, but in order to balance low-temperature dimensional change rate, flyability, and thermal conductivity at low density, water is It turns out that effectiveness and amount added are important.

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〔Effect of the invention〕

According to the present invention, it is possible to obtain a rigid polyurethane foam that has a low density, a lower thermal conductivity than conventional foams, and excellent low-temperature dimensional stability and fryability.

Claims (1)

[Scope of Claims] 1. A method for producing a rigid polyurethane foam by reacting a polyol component and an isocyanate component in the presence of a reaction catalyst, a blowing agent, and a foam stabilizer, wherein the polyol component has an OH value of 440 to
480 consisting of a mixture of the following () to () (i) adipic acid polyester 14 to 18% by weight, (ii) phthalic anhydride polyester 9 to 5% by weight, (iii) tolylene diamine polyether 60 to 55% by weight, (iv) Pentaerythritol polyether 17~
22% by weight of a rigid polyurethane foam. 2. The method for producing a rigid polyurethane foam according to claim 1, wherein the blowing agent is a lower fluorinated chlorinated hydrocarbon and water.