JPH028609B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for manufacturing rigid urethane foam. More specifically, the present invention relates to a method for producing a rigid urethane foam having uniform open cells and excellent flame retardancy. Conventionally, most of the cells in rigid urethane foam, which has been widely used industrially, are closed cells.
By trapping gas with low thermal conductivity within the bubbles, it has an excellent insulation effect.
It is mainly used for insulation purposes. but,
In hard urethane foam with such a closed cell structure, the pressure of the gas inside the cells changes depending on the outside temperature (the temperature at which it is used), and if the resin film that makes up the cells is not strong enough, it may shrink at low temperatures or shrink at high temperatures. Unfavorable phenomena such as expansion over time are observed.
For this reason, even if one attempts to reduce the density of the foam by reducing the thickness of the resin film, there is a limit.
Furthermore, closed-cell foams do not have sufficient sound absorption properties or air permeability. On the other hand, foams with open cells do not have any problems in terms of the strength of the resin film, and are also excellent in terms of sound absorption properties and air permeability, so various rigid urethane foams with open cells have been studied. The reality is that if the bubbles become non-uniform or the conditions during foaming change, the bubbles will collapse, and a method for obtaining a rigid urethane foam with a stable open cell structure has not yet been established. In view of such circumstances, the present inventors have conducted extensive research and found that polyols, polyisocyanates, blowing agents,
When manufacturing rigid urethane foam by blending foam stabilizers and catalysts, a halogenated polyether polyol with a specific structure is used as a polyol component to create a uniform, fine cell structure and excellent flame retardancy. The present inventors have found that a rigid urethane foam with an open-cell structure having properties can be easily produced, and based on this knowledge, they have completed the present invention. That is, the present invention provides: (1) General formula [In the formula, x is a number from 0 to 7, A is a saturated or unsaturated brominated diol residue, and R represents hydrogen or an alkyl group having 1 to 5 carbon atoms]. (2) about 5 to 20 parts by weight of water per 100 parts by weight of the polyol component, and (3) polyisocyanate having about 0.4 to 1.0 equivalents of isocyanate groups per equivalent of active hydrogen in the polyol component and water as a catalyst and foam stabilizer. This is a method for producing a rigid urethane foam, which is characterized in that the reaction is carried out in the presence of an agent. Examples of the polyether polyols used in the present invention include polyether polyols represented by the following formula (eg, those described in Japanese Patent Publication No. 56-24654 and Japanese Patent Application Laid-Open No. 50-70312). [In the formula, x is a number from 0 to 7, A is a brominated saturated or unsaturated diol residue, and R represents hydrogen or an alkyl group having 1 to 5 carbon atoms] Halogen represented by the above formula Among the polyether polyols, those in which R is hydrogen are particularly preferred. For example, the halogenated polyether polyol represented by the above formula has the following general formula: The polyglycidyl ether of epichlorohydrin oligomer represented by the formula [where x and A have the same meanings as above] is hydrolyzed in a diluted acidic medium (e.g. nitric acid, perchloric acid, etc.) or
~5 monohydric aliphatic alcohols (e.g. methanol,
It can be obtained by alcoholysis using ethanol, propan-1-ol, tertiary butyl alcohol, etc.). The polyglycidyl ethers of epichlorohydrin oligomers of the above formula can be obtained in a manner known per se by oligomerization of epichlorohydrin initiated with brominated saturated or unsaturated aliphatic dihydroxy compounds having 2 to 6 carbon atoms. It is produced by dehydrochlorination of halogenated polyether polyols having terminal chlorohydrin groups. For example, glycerol monobromohydrin,
3,4-dibromo-butane-1,2-diol,
2,3-dibromobutane-1,4-diol,
2,3-dibrombut-2-ene 1,4 diols, 3,4-dibrombut-2-ene-1,2-
Oligomerization of epichlorohydrin initiated by diols, saturated or unsaturated brominated diols such as 2,2 bis-bromomethyl-propane 1,3 diol and 1,2,5,6 tetrabromohexane 3,4 diol It can be obtained by dehydrochlorinating the halogenated polyether polyols obtained by. The polyether polyol represented by the above formula may be used alone or in combination with other polyether polyols such as those used in the production of rigid urethane foams. Examples of polyether polyols that can be used in combination include those having a functional group number of 2 to 8 and a hydroxyl value of about 350 to 800 mgKOH/g. When used in combination, the weight ratio of the polyether polyol represented by the above formula to the other polyether polyol is in the range of about 0 to 20 to about 100 to 80 for the former. In the present invention, water is used as a blowing agent. Approximately 5 to 5 parts of water per 100 parts by weight of the polyol component
It is used in a proportion of 20 parts by weight, especially about 6 to 15 parts by weight. If the amount of water used is less than 5 parts by weight, the foam will have a closed cell structure, and the foam will tend to shrink. On the other hand, if the amount of water exceeds 20 parts by weight, undesirable phenomena such as the foam collapsing during foaming occur. In the present invention, in addition to water, chlorinated fluorinated hydrocarbons such as trichlorofluoromethane and dichlorodifluoromethane can be used as blowing agents. The amount varies depending on the desired density of the foam, but is approximately 0 to 60 parts by weight per 100 parts by weight of the polyol component. As the polyisocyanate component used in the present invention, polymethylene polyphenylene polyisocyanate commonly referred to as "C-MDI" can be used. For this polymethylene polyphenylene polyisocyanate, for example, tolylene diisocyanate (TDI), crude tolylene diisocyanate (C-TDI), diphenylmethane diisocyanate (P-MDI), or these isocyanates and polyols are combined into a polyisocyanate. It is also possible to use a so-called prepolymer obtained by reacting an excess of the former in a range of about 0 to 50 parts by weight to about 100 to 50 parts by weight of the former. The amount of these isocyanate components used is such that the number of equivalents of isocyanate groups (NCO index) is about 0.4 to 1.0, preferably about 0.6 to 0.8, per equivalent of active hydrogen of the polyol component used and the water used as a blowing agent. It is. When the NCO index exceeds 1.0, the resulting foam becomes brittle. On the other hand, when it is less than 0.4, the form collapses. Examples of the catalyst used in the present invention include tertiary amines that are normally used in producing rigid urethane foams. Examples of tertiary amines include triethylamine, dimethylethanolamine, dimethylcyclohexylamine, tetramethylethylenediamine, tetramethylpropanediamine, tetramethylhexamethylenediamine,
Examples include hexamethylene diethylene triamine. Two or more of these tertiary amines may be used in combination. The amount of catalyst used is appropriately selected depending on the type of amine and the required foaming rate.
Usually, the amount is in the range of about 0.5 to 10 parts by weight per 100 parts by weight of the polyol component. As the foam stabilizer used in the present invention, there is no need to use a special silicone oil that has a foam-breaking effect, and silicone foam stabilizers that are generally used for rigid urethane foams can be used. In addition to the catalyst and foam stabilizer, for example, stabilizers, fillers, pigments, etc. may be added as necessary. In the present invention, a rigid urethane foam is obtained by reacting a halogenated polyether polyol, water and a polyisocyanate in the presence of a catalyst and a foam stabilizer. The reaction is carried out by means known per se, such as the one-shot method (prepolymer method) or the flowing method (foaming agent). According to the method of the present invention, it is possible to easily and reproducibly produce open-cell hard foam having a low density of approximately 6 to 20 kg/m ³ and uniform cells without using any special foam stabilizers. Urethane foam can be manufactured. Even though the resulting foam has a low density,
Dimensional changes at low and high temperatures are extremely small compared to conventional hard urethane foam. Moreover, the obtained hard urethane foam has extremely excellent flame retardancy. Further, since the open-cell rigid urethane foam obtained by the present invention has a uniform and fine cell shape, it is excellent in terms of heat insulation performance and water absorption. The method of the present invention can be applied on-site using conventional methods such as injection methods and spray methods, and can be used for various heat insulation and sound insulation applications, including heat retention and insulation applications. EXAMPLES The present invention will be explained in more detail with reference to Examples and Comparative Examples below. In Examples and Reference Examples,
Ixol B-251 and Ixol M-125 are halogenated polyether polyols manufactured by Solvay Co., Ltd. based on the method disclosed in JP-A-56-24654. Ixol B-251 is a halogenated polyether with an OH No. of 345mgKOH/g, a viscosity (at 25°C) of approximately 6500cps, a bromine content of 32%, and a chloro content of 7%.
125 is OHNo.235mgKOH/g, viscosity (25℃) approx.
It is a halogenated polyether with 2500 cps, bromine content of 33%, and chloro content of 7%. Example 1 Ixol B-251 100 in a 2-handled poly beaker
g, Silicone F-305 (manufactured by Shin-Etsu Chemical) 3 g, dimethylcyclohexylamine 2.6 g, pure water 15 g, and Freon 11 30 g were weighed out and stirred uniformly.
139 g of polymethylene polyphenylene polyisocyanate (C-MDI; NCO index 0.45)
The mixture was poured into a box measuring 25 cm x 25 cm x 20 cm after being stirred uniformly. At this time, the temperature of each liquid was adjusted to 20℃, and its reactivity was 11.
With a gel time of 38 seconds, the obtained rigid urethane foam has a very fine cell structure and a density of
13.6Kg/m ³ , completely open cell ohm with 0% closed cell ratio, DIN65% compressive strength 0.16Kg/cm ²
It was hot. Example 2 In the same manner as in Example 1, Ixol B-251 100
g, silicone F-305 3g, dimethylcyclohexylamine 2.6g, pure water 15g, Freon 11 30g
Weigh out and stir evenly, then add 310g of C-MDI.
(NCO index 1.0) was poured into the box, stirred uniformly, and injected into the box. The resulting foam had an open cell ohm with a cream time of 15 seconds, a gel time of 46 seconds, a closed cell ratio of 0%, and a density of 18.1 kg/m ³ . The compressive strength was 0.75Kg/ ^cm2 . Example 3 In the same manner as in Example 1, Ixol B-251 100
g, silicone F-305 3g, dimethylcyclohexylamine 2.6g, pure water 12g, Freon 11 60g
The reactivity of the foam obtained by reacting with 159 g of C-MDI (NCO index 0.6) was 11 seconds for cream time, 50 seconds for gel time, and the density was 9.1 kg/
^m3 , closed cell ratio 0%, compressive strength 0.19Kg/ ^cm2 , tensile strength 0.29Kg/ ^cm2 , elongation rate 38%, thermal conductivity
It was 0.0317Kcal/m.hr℃. Example 4 100 g of Ixol B-251 in the same manner as in Example 1,
3g of silicone F-305, 1.7g of dimethylcyclohexylamine, 12g of pure water and 159g of C-MDI
The reactivity of the foam obtained by reacting with (NCO index 0.6) is 15 seconds for cream time, 37 seconds for gel time, density is 15.3Kg/m ³ , and closed cell ratio is 0.
%, and the compressive strength was 0.63 Kg/cm ² . Example 5 100 g of Ixol B-251 in the same manner as in Example 1,
Silicone F-305 3g, dimethylcyclohexylamine 1.7g, pure water 6g, Freon 11 60g
The reactivity of the foam obtained by reacting with 104g of C-MDI was 14 seconds for cream time and 72 seconds for gel time.
seconds, density is 10.4Kg/m ³ , compressive strength 0.38Kg/cm ² ,
Closed cell ratio 0%, tensile strength 0.45Kg/cm ² , elongation rate 28
It was %. Comparative Example 1 100g of Fyrol 6, a commercially available reactive flame retardant,
Silicone F-305 3g, dimethylcyclohexylamine 1.7g, pure water 12g, Freon R-11 50g
When 167 g of C-MDI (NCO index 0.6) was reacted, the foam broke after 14 seconds of cream time and only a foam with very rough cells was obtained. Comparative Example 2 Actocol GR-09 (glycerin base, OH value 400) commercially available as a flame retardant polyol
100g, silicone F-305 3g, dimethylcyclohexylamine 2.6g, pure water 12g, Freon 11
60g and 167g C-MDI (NCO index 0.6)
When reacted with the cream, the foam broke after 12 seconds of cream time, and a foam with extremely rough cells that could not be used for practical use was obtained. Example 6 In the same manner as in Example 1, 100 g of Ixol M-125, 3.0 g of silicone foam stabilizer F-305, 12 g of water, 2.5 g of dimethylcyclohexylamine and Freon 11 30
Mix g in advance and add C-MDI to this.
Add 166g (NCO index 0.7) and mix vigorously for 10 seconds with a mixer to form a 25cm x 25cm x 20
The mixture was transferred to a cm box and foamed. Foaming started 20 seconds after mixing, and the rise time was 45 seconds.
The resulting foam has uniform fine cells and a density
The weight was 10.3Kg/m ³ and the closed cell ratio was 0%. Examples 7 to 9 and Comparative Examples 3 to 5 Foaming tests were carried out in the same manner as in Example 1 by varying the amount of water used relative to 100 parts of Ixol B-251. The appearance of the foam during foaming and the properties of the foam were as follows.

【table】

[Table] Shrinkage Slight shrinkage Good Good Good
From the above examples and comparative examples, the amount of water used is 6 parts or more per 100 parts of halogenated polyol.
It was found that a good foam can be obtained up to about 15 parts. Examples 10 to 12 and Comparative Examples 6 to 7 The amount of blowing agent was fixed in the same manner as in Example 1,
Foams were foamed using the formulations shown in the table below, and the foaming behavior and appearance of the foams were examined.

[Table] In the above Examples and Comparative Examples, when the amount of isocyanate used was NCO index 0.3, a good foam could not be obtained, but when the amount was in the range of 0.6 to 1.0, an open cell ohm with a fine cell structure could be obtained. did it.

Claims (1)

[Claims] 1. General formula [In the formula, x is a number from 0 to 7, A is a saturated or unsaturated brominated diol residue, and R represents hydrogen or an alkyl group having 1 to 5 carbon atoms]. 2. About 5 to 20 parts by weight of water per 100 parts by weight of the polyol component, and 3. A polyisocyanate having about 0.4 to 1.0 equivalents of isocyanate groups per equivalent of active hydrogen of the polyol component and water in the presence of a catalyst and a foam stabilizer. A method for producing hard urethane foam characterized by reacting with.