JPS5867712A - Preparation of phenolic foam having improved heat insulating preformance - Google Patents

Abstract

PURPOSE:To obtain the titled foam having a higher elasticity, by using an alkoxyetherified phenolic resin prepared by etherifying a phenolic resin obtained in a specific pH region with a monohydric alcohol as a raw material. CONSTITUTION:(A) An alkoxyetherified phenolic resin prepared by reacting (i) a phenol with an aldehyde at 3-8pH, to give a phenolic resin, and etherifing the resultant phenolic resin with (ii) a monohydric alcohol, e.g. methanol, is foamed and cured with (B) a polyisocyanate, e.g. diphenylmethane diisocyanate, in the presence of (C) a foaming agent, preferably chlorotrifluoromethane, and if necessary (D) a co-catalyst, preferably an amine compound, and (E) a foam stabilizer, e.g. dimethylsiloxane-polyoxyalkylene cocondensate, to give the aimed foam.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a phenol foam that has particularly improved heat insulation performance by using a specific phenolic resin, and more particularly relates to
This invention relates to a method for producing a 7-ohm material with high heat insulation performance and elasticity, which comprises using an alkoxy ether compound obtained by etherifying a phenolic resin obtained in the above with a monofunctional alcohol. , its purpose is to replace the conventional novolak 11 phenol 4
The purpose is to further improve the heat insulating performance and elasticity of the foam obtained by reacting Ir11 or resol type phenolic resin with polyisocyanates.

Generally, such phenolic forms are resole-type pheno-A/fI! It is obtained by foaming and curing fat using a cocatalyst in the presence of a foaming agent, but since an acidic substance is used for this curing, if the resulting foam is brought into contact with a steel plate, etc. It had the disadvantage of causing rust. Additionally, this type of phenolic form has
Other disadvantages were that it had high flyability, lacked elasticity on the surface, and became crumbly.

In order to improve these drawbacks, many studies have been made to use polyisocyanates as crosslinking agents for phenolic resins. For example, U.S. Patent No. 2608
As described in Japanese Patent Publication No. 556, there is a method to improve metal corrosion, which is one of the drawbacks of conventional phenol foam using an acid catalyst, by using polyincyanates as a crosslinking agent. As described in Japanese Patent No. 1-27093, there is a method in which a foam is obtained by reacting a phenol resin with a polyincyanate for the purpose of improving surface roughness.

However, because the method involves completely leaving the methylol groups in the phenol resin and reacting them with the polyincyanates, the reaction occurs rapidly and generates a large amount of heat.
In particular, when the foaming agent 1 is used, the foaming pressure rises rapidly and the cell film in the formed layer 11 is ruptured, resulting in the resulting foam having a large number of so-called open cells. As a result, the closed cell ratio of the foam becomes low, the thermal conductivity becomes high, and the heat insulation performance is deteriorated.

Another disadvantage of leaving a large number of methylol groups is that the methylol groups, which act as crosslinking points, increase the degree of crosslinking of the resulting foam, resulting in problems during handling such as transportation or during panel assembly. It is easily damaged by stress etc.

However, the present inventors reacted phenols and aldehydes in a pH range of 3 to B, and then added one or more monofunctional alcohols to the obtained phenol resin at a pH of 7 or less. The alkoxyetherified phenol resin obtained by reacting to etherify the methylol groups in the mosquito phenol resin is foamed together with polyisocyanates in the presence of a foaming agent using or using a cocatalyst. When hardening,
The foaming reaction becomes gentler, and the resulting foam has extremely low thermal conductivity, and therefore has extremely high heat insulation performance and high elasticity, reducing problems such as damage to the foam during handling such as transportation. Having discovered this, we have completed the present invention.

That is, the present invention combines phenols and aldehydes into three
The phenolic resin obtained by the reaction in a pH range of ~8 is reacted with a monofunctional alcohol, and the resulting alkoxyetherified phenolic resin and polyincyane (B) are reacted in the presence of a blowing agent C), Co-catalyst (
The present invention provides a method for producing a phenol foam, which comprises foaming and curing with or without the use of a phenol foam.

Here, the above-mentioned phenolic resin (FMA) refers to a product obtained through a two-step reaction in which the phenol resin is first obtained by a resin production reaction, and then the target product is obtained by an alkoxy etherification reaction, and the first step is a resin production reaction. In the reaction, the raw materials, phenols and aldehydes, are heated to pH 5~
The pH is preferably adjusted by adding a metal salt of a weak acid. Typical examples of metal salts of the above-mentioned weak acids are organic carboxylic acids and metal salts such as carbonic acid.As organic carboxylic acids, oxalic acid, maleic acid, phthalic acid, or naphthenic acid are used. Examples of the metal used include zinc, lead, manganese, tin, cobalt, sodium, or potassium.

Typical examples of the phenols include phenol, cresol, xylenol, and resorcinol, while typical examples of the aldehydes include formalin, paraformaldehyde, trioxane, and furfural.

1 to 4 moles of aldehydes are used per mole of phenols, and in order to maintain the pH of the system at 3 to 8, one or more metal salts of weak acids are added to 1 mole of phenols. Use 5% by weight.

Put each raw material in a predetermined ratio into a reaction container and stir while stirring.
The temperature is raised to an arbitrary temperature within the range from 0° C. to the reflux temperature, and the reaction is allowed to occur for a predetermined period of time. The reaction time depends on the reaction temperature,
It also depends on the pH of the system, and the reaction temperature is set at 50°C.
Although the reaction proceeds even if the temperature is lower than ℃, the reaction time becomes extremely long and becomes impractical, so the temperature should be within the above range.

Next, in the second stage reaction, the phenol resin thus obtained is etherified with a monofunctional alcohol. Add more than pH 7
The following is preferably carried out at a pH of 5 or below. If the pH of this system exceeds 7, it is advisable to use an acid to adjust the pH to 7 or less, preferably 5 or less.

Suitable acids used in this case include hydrochloric acid, sulfuric acid, phosphoric acid, oxalic acid, maleic acid, acetic acid, and sulfamic acid.

Furthermore, typical monofunctional alcohols include methanol, ethanol, glopanol, and butanol.

This etherification reaction does not proceed in a range exceeding pH 7, and the time for this reaction is determined by the desired degree of etherification, but after the completion of the etherification reaction, it is immediately contained in the system under reduced pressure rather than normal pressure. By removing water and excess monofunctional alcohol that has not been etherified, the desired liquid alkoxyetherified phenol resin is obtained.

The phenolic resin (4) thus obtained is as follows:
Preferably, the amount of water and the monofunctional alcohol component are each 11 or less. Excess water in the resin (4) reacts with the polyinsyanate @B) to generate carbon dioxide gas and has the effect of lowering the closed cell ratio, while the monofunctional alcohol component hinders curing. Since it has an effect, it should be suppressed to the above-mentioned limit.

In addition, the degree of etherification of the tree 111mA) is determined by the amount of each free monofunctional alcohol component contained in the cough resin, the total amount of the free and etherified alcohol component, and the amount of water and alcohol component. It is determined from the OH value of the resin, and the specific calculation method is as follows.

Thus, said phenol I! used in the method of the invention! The degree of etherification of fMldA) is 10 to 90.
% range is desirable.

If it is less than 10%, the effect of the present invention cannot be expected, and if it is more than 90%, it lacks the reactivity to obtain a foam, so both are not preferred.

The degree of etherification greatly affects the reactivity with the polyincyanate@B), and the higher the degree of etherification, the milder the reaction, while the lower the degree of etherification, the more intense the reaction, and the more severe the reaction becomes. Decrease bubble rate.

To 100 parts by weight of the alkoxyetherified phenol tree shunshu obtained in this way, 0 to 5 parts by weight of the supporting agent and 0 to 5 parts by weight of the foam stabilizer (t) are mixed, and then the resulting mixture Foamed cotton C) in the liquid, especially vaporized foaming agent 1~
51 parts by weight are added and mixed, and further 10 to 2001 L parts of polyinsyanate@Bl are added and mixed,
Addition amount of each of these components + i pre-distributed phenol * 1 of raw material A)
00 parts by weight.

After addition and mixing of polyisocyanate (B), heat generation occurs, and the vaporized foaming agent is vaporized by this heat generation to cause foaming, and at the same time, curing progresses and a foam is obtained.

Here, a typical example of the above-mentioned foam thinning material is a dimethylsiloxane/polyoxyalkylene cocondensate, but it is of course not limited to this.

In addition, basic compounds, tertiary phosphines, metal soaps, and the like can be used as the additive, but amine compounds are particularly suitable.

The co-catalyst (9) and the foam stabilizer may or may not be used, and the purpose of the co-catalyst is to promote the reaction.

Furthermore, as the vaporized foamed NF), any substance whose boiling point at normal pressure is in the range of 10 to 100°C can be used, but chlorotrifluoromethane, 1, 1.2-)lichloro-1,2,2-)
Examples include refluoroethane, petroleum ether, penta/or methylene chloride, and the like.

Next, it is known that the polyisocyanate @rumor usually reacts with water to generate carbon dioxide gas, and it is possible to use this, but in the case of carbon dioxide gas foaming, the reaction is rapid. When carrying out the method of the present invention, the amount of water in the phenol vj4 oil is kept as small as possible to prevent such reactions. should be avoided as much as possible.

Polyincyanate) [B) refers to those having two or more incyanate groups in one molecule,
Typical examples include toluene diincyanate (TDI), crude TDI, diphenylmethane diincyanate (MDI), crude MDI, and polymethylene polyphenylisocyanate.

The present invention relates to a process for the production of 7 ohms based on the reaction of alkoxyetherated phenol IImA) and polyincyanate@B), respectively, as described above.
When carrying out the method of the present invention, in addition to the above-mentioned components, fillers, flame retardants, reaction modifiers, and the like may be added.

Incidentally, as a result of the use of polyincyanates, the foam obtained by the method of the present invention may have lower "'C flammability than conventional acid-curing phenol foams," or may have a flame-retardant flame retardant to compensate for this. agent, melamine, melamine resin,
Addition of urea, urea-based resin, antimony-based flame retardant, halogen-based flame retardant, etc. is particularly suitable for improving fire prevention performance.Next, the present invention will be specifically explained using Examples and Comparative Examples. All percentages and parts are based on weight.

Example 1 Phenol 8519.37% formalin 949# and zinc acetate 2.59 were charged into a four-loaf flask equipped with a thermometer, reflux condenser and stirrer, and reacted at reflux temperature for 2 hours.

The pH of the reaction solution at this time was 5.2. Then 60
1081 g of ethanol and 11 g of 85% phosphoric acid were added thereto, and the temperature was again raised to reflux temperature and reacted for 2 hours. The pH of the reaction solution at this time was '5.8.Here, After adjusting the pH to 7 Kli using caustic powder, dehydration was performed under reduced pressure, and dehydration was stopped when there was no more distillation at a reduced pressure of 6800H77.The alkoxyetherified phenolic resin obtained here had a viscosity of 0.0
cps (25℃; the same applies hereafter), water power α5%,
The degree of etherification was 87%.

Next, 111 of Shin-Etsu Silicone F110J as a bubble stabilizer and 1 g of triethylamine were added to this resin 1001 and mixed well, and the resin temperature was increased to 20".
Adjusted to below C.

After that, "Freon 11" was added to the resulting resin liquid.
(Chlorotrifluoromethane manufactured by Mitsui Fluorochemical ■)
Mix 10 parts and stir well.
(crude MDI made by Nippon Polyurethane) 10D
The mixture was quickly stirred and mixed, and then poured into a wooden mold lined with release paper and foamed. When this series of foaming and curing was carried out at room temperature, the foaming was completed in 2 minutes and 20 seconds, and at the same time, the surface of the obtained foam was hardened to such an extent that it could no longer be dented even when pressed.

The density of the obtained foam is α052117cm”, the compressive strength is t8kg, and the bending strength is ’5.7k41/
It was extremely elastic, with a crsζ flexural modulus of 70 kl/cts'', a thermal conductivity of α018 keel/m, br, °C, and a bubble rate of 85%.

Comparative Example 1 The reaction was carried out at reflux temperature for 2 hours, and then dehydration was immediately carried out under reduced pressure, and the dehydration was continued at a reduced pressure of 680 μH, 9 until there was nothing left to be distilled.
The same procedure as in Example 1 was carried out.

The resin obtained here had a viscosity of 9,650 ep- and a moisture content of α7%.

Next, foaming was carried out in the same manner as in Example 1 except that this M fat was used, but the foaming curing time was 1 minute and 25 seconds, and the resulting foam had a density of α0369/cm".
Compressive strength is 11'QA, bending strength is 2.0YA,
Flexural modulus is 90 Yu/l, thermal conductivity is a 026 ke
aj, 4. hr, 'C1 closed cell car was 45%, and compared to the foam obtained in Example 1, the single piece thermal conductivity was higher, the closed cell ratio was lower, and it was hard and elastic.

Example 2 Phenol 7549, 57% formalin 566, jii
80% paraform 2659 and 7.4 g of 24% lead naphthenate were charged into a reaction vessel similar to that used in Example 1, and then reacted at 90° C. for 4 hours while stirring. The pH of the reaction solution at this time was 4.1. After that, n-butanol 2.590. After adding p and reacting at reflux temperature for 1 hour and 30 minutes, dehydration and removal of butanol were performed under reduced pressure.

The resin thus obtained had a viscosity of 13500 cps,
Water content was α6%, free n-butanol (L8%), and the degree of etherification was 70%.

To 100g of this resin, ``Shin-Etsu Silicone F110JIIi'' and 1g of diptyltin silacrate as bubble stabilizers were added and mixed well, and then [Freon 11!IJ
(Mitsui Fluorochemical ■1.1.2-) Lichloro-1
, 2,2-trifluoroethane) 2011 was added and mixed. Next, 100 g of "Crude MDI" was added and quickly stirred, poured into a wooden box lined with release paper, and foamed at room temperature.

Further, the foaming curing time at this time was 2 minutes and 10 seconds.

The obtained form has a density of α053 El/c♂
The compressive strength is 'LAkg/cm - the bending strength is 29~/
c/, bending elastic modulus is 65'Q/amζ thermal conductivity is 0.0
17 kca#An, hr, 'C1 closed cell ratio is 86%
It was very elastic.

Example 3 The same procedure as Example 1 was carried out except that 50 parts of melamine was added to 100 parts of the phenolic resin before adding "Freon 11".

The obtained form has a density of αosom/bacterium 1,
Pressure is over 111 t 5 kl/cyn - thermal conductivity is 10
18 ke@I/h+, hr, 'C5 closed cell ratio is 84
%, and it self-extinguished immediately even if it caught fire.

As has become clear from the above, the method of the present invention has the following features.

1) By using polyincyane) [B) as a crosslinking agent for phenol 1()IIIA), gold
4) Non-corrosive phenol foam can be produced; 2) Phenol with many dimethylene ether bonds obtained by performing a phenol resin production reaction under conditions of pH 3 to 8.
mB), it is possible to produce a phenolic foam with lower fryability compared to conventional foams using ordinary alkaline resol resins or acid novolac resins; 3) In addition, phenolic resins By using alkoxyetherified phenol fM as
Compared to conventional phenolic resins that are not alkoxyetherified, the closed cell ratio is much higher (
4) Furthermore, by alkoxyetherifying the methylol groups of the phenolic resin, it is possible to produce a phenolic foam that has low thermal conductivity and therefore has particularly excellent thermal insulation performance. A more elastic phenolic foam is obtained than when resin is used.

Claims (1)

[Scope of Claims] An alkoxyetherified phenol resin obtained by reacting a captive phenol and an aldehyde at a pH of 3 to 8, and then etherifying the resulting phenol resin with a monofunctional alcohol; ) Polyincyanate foam is foamed and cured in the presence of (C) a foaming agent, (C) with or without a foam stabilizer, and (E) a foam stabilizer. A method for producing high phenol foam.