JPS63175042A - Production of phenolic resin foam - Google Patents

Abstract

PURPOSE:To obtain the titled foam suitable for building material, etc., preventing corrosive properties on metals, by blending a liquid phenolic resin of resol type with barium metaborate as a neutralizing agent. CONSTITUTION:(A) A liquid phenolic resin of resol type is blended with (B) a blowing agent, (C) a foam stabilizer, (D) a curing agent, preferably sulfuric acid and (E) barium metaborate as a neutralizing agent to give the aimed foam. The amount of the component E is preferably 1-30pts.wt. based on 100pts.wt. component A.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for producing a phenolic resin foam that is suitable for building materials, furniture, fittings, and industrial materials and prevents corrosion against metals.

(Prior Art) Conventionally, resol-type phenolic resin foams are produced by adding a blowing agent, a foam stabilizer, a curing agent, etc. to a resol-type phenolic resin obtained by reacting phenols and aldehydes in the presence of an alkali catalyst. It is obtained by adding and foaming and curing. (Japanese Patent Publication No. 44-31839, Japanese Patent Publication No. 57-180643, etc.) As curing agents, inorganic acids such as hydrochloric acid and sulfuric acid, and organic acids such as para-toluenesulfonic acid, benzenesulfonic acid, phenolsulfonic acid, and xylene sulfonic acid are used. used. These are all strongly acidic substances, and they remain as free acids in the foam-cured resol type phenolic resin foam, so if the foam comes into contact with metal in the presence of air or water, it will corrode the metal. This improvement is desired because of the disadvantage of

In order to prevent corrosion of such metals, it has been proposed to incorporate a neutralizing agent, and JP-A-58-154,734 discloses IlA group carbonates as a neutralizing agent.
, No. 931, mA with a particle size of 10 to 500 μm,
It has been proposed to use carbonates of the JIB group. Specific examples of these neutralizing agents include MgCO3, CaCO5
+ SrCO3+ 2ZnCOa・3Zn(OH)z・
Basic carbonates such as H2O are disclosed.

It is also conceivable to practically use metal hydroxides such as Az(OH)3 and Zn(OH)z as neutralizing agents.

It is often thought that by using these neutralizing agents, the pH of Myoken Foam will be 7 or higher and metal corrosion will not occur.
It is virtually impossible to prevent metal corrosion. Even if the amount of neutralizer is increased to raise the pH of the phenol foam to 8-9, the effect of preventing metal corrosion will not be sufficient, many voids will occur in the foam, and the K value and compressive strength will decrease. It becomes more practical and i.

For example, sodium hydroxide, potassium hydroxide, calcium hydroxide, magnesium hydroxide, zinc hydroxide, strontium hydroxide, calcium oxide, magnesium oxide, sodium carbonate, potassium carbonate, calcium carbonate, strontium carbonate, etc. are added to the phenolic resin. rear,
When additives such as a foaming agent, foam stabilizer, and hardening agent are added, the neutralization reaction between these alkaline substances and the acidic substance of the hardening agent is rapid, and foaming occurs as the hardening agent is added, making stirring impossible and resulting in uniform foaming. There are drawbacks such as not being able to obtain a foam, or the curing speed being significantly reduced, resulting in insufficient curing resulting in the foam becoming crumbly, shrinking, and significantly decreasing mechanical strength.

Magnesium carbonate and aluminum hydroxide, which have a relatively slow neutralization reaction with the curing agent, have a small decrease in curing speed during foaming, yielding a preferable foam, and lowering the acidity of the foam. Corrosivity to metals is not improved at all.

The reason why these neutralizing agents are not sufficient to prevent metal corrosion is that the sulfate generated by neutralization has a high solubility in water, as shown in Table 1, and the presence of this sulfate has no effect on metal corrosion. It is assumed that this is having an effect.

(Specific means for solving the problem) It is possible to obtain a phenol foam in which metal corrosion is prevented without significantly lowering the strength.

That is, the solubility of B a S 04, which is a neutralized salt, is
0.000115 at 0℃? and o, o at 100℃
o.

412 and other sulfates. In addition, the reaction with sulfuric acid, which is a curing agent, is rate-limiting, and the strength of the foam decreases little.

(Structure of the Invention) The present invention provides a method for manufacturing a resol type phenolic resin foam by blending a blowing agent, a curing agent, and a neutralizing agent with a liquid resol type phenolic resin, in which barium metaborate is used as the neutralizing agent. The present invention provides a method for producing a phenolic resin foam, which is characterized in that the foam is blended with a phenolic resin.

Resol-type phenolic resins are obtained by condensing phenols and aldehydes in the presence of an alkaline catalyst, and suitable phenols include homologues such as phenol, cresol, and xylenol, or mixtures thereof. . Suitable aldehydes are formaldehyde, paraformaldehyde, acetaldehyde and other aldehydes and mixtures thereof.

The appropriate blending ratio of phenols and aldehydes is 1.3 to 2.0 moles of aldehydes per mole of phenols.

After completing the condensation reaction of phenols and aldehydes, the composition is dehydrated under reduced pressure and has a viscosity of 800 to 1 at 25°C.
It is desirable to concentrate to 0,000 centivoids.

Foaming agents include hydrocarbons such as petroleum ether, n-pentane, and n-hebutane, and halogenated compounds such as trichloromonofluoromethane, chloropentane, nato-5-chloromonofluoroethane, trichlorotrifluoroethane, methylene chloride, and trichloroethylene. Hydrocarbons having a boiling point of 10 to 100°C are suitable.

As the foam stabilizer, nonionic surfactants such as silicone-based and polyoxyalkylene-based surfactants can be used alone or in combination.

Examples of the curing agent that can be used in the present invention include hydrochloric acid, inorganic acids such as sulfuric acid, and organic sulfonic acids such as phenolsulfonic acid, p-toluenesulfonic acid, benzenesulfonic acid, and xylene sulfonic acid.

The use of barium metaborate as a neutralizing agent varies depending on the type and amount of curing agent used, but it is usually 1 to 30 parts by weight, preferably 5 to 20 parts by weight, based on the weight of the resol type phenolic resin Zoo. Kagebe is heavy.

If the amount exceeds 30 parts by weight, the acidity of the foam will decrease, but the mechanical strength will decrease and brittleness will increase, which is not preferable. In addition, if the number of weeping parts is less than one, the acidity of the foam is high and corrosion to metal cannot be prevented.

The particle size of the barium compound is preferably 50 μm or less. s
If it is larger than o pm, many voids will occur in the foam, resulting in a decrease in heat insulation and a decrease in mechanical strength, which is not preferable.

In addition to these components, it is also possible to add other inorganic additives, polyalkylene glycols, glycidyl ether compounds, etc. (Examples) The present invention will be explained below with reference to Examples. Note that the present invention is not limited to these Examples.

Moreover, all "parts" described in each example indicate "parts by weight."

Example of production of phenol resin In a reaction vessel equipped with a cooler and a stirrer, ioo parts of phenol,
130.8 parts of 377a formalin and 4.1 parts of a 47.1% caustic soda aqueous solution were charged, and the temperature was gradually raised until it reached 98°C. After refluxing for 45 minutes, the mixture was heated to 75°C.
After lowering the temperature to
I stopped dehydration when it reached 1,500 centipoise. After lowering the temperature to 25° C., 3 parts of Toray Silicone silicone oil 5H193 (trade name) as a surfactant was added to obtain 71 parts of resol type phenolic resin Al. In addition, the moisture content of resin A was 1fd16.6%.

Example - To 00 parts of Luresol type phenolic resin Al, 11.06 parts of barium metaborate was added and stirred for 60 seconds, 8.0 parts of trichlorotrifluoroethane was added and stirred for 90 seconds, and further 8.7 parts of 57.5% sulfuric acid was added. Add and stir for 80 seconds, then add 3
It was poured into a wooden frame measuring 00 x 300 x 300 m and heated at 80°C for 1 hour.

Density, Kitlt, compressive strength L pH of the obtained foam
and corrosivity are as shown in Table-1. The pH of the foam is 6.
Although not so high in OO, the amount of corrosion tc on the liquid contact surface and the foam contact surface was smaller than in Comparative Example 1 in which no neutralizing agent was used, and the corrosivity was significantly improved.

Example 2 A resol type phenolic resin foam was obtained in the same manner as in Example 1 except that barium metaborate was used in the amount shown in Table 1. Foam pI (and corrosivity) was improved.

Comparative Example-1 A resol type phenolic resin foam was obtained in the same manner as in Example-1 without using a neutralizing agent. The pH of the foam is as low as 2.55, and the corrosion resistance of the liquid contact surface and the foam contact surface are each 10
It was large at 5111F and 355η.

Comparative Example 2 A resol type phenolic resin foam was obtained in the same manner as in Example 1 except that magnesium carbonate having a particle size of 200 to 250 m was used as a neutralizing agent. Many voids were generated in the foam, and the Kl directivity and compressive strength were deteriorated, but this was caused by the large particle size of magnesium carbonate. foam p
H was 3.96, but corrosivity was not improved and it was 9.

Magnesium carbonate 4-73 (f%) / 1.1
(molar ratio), but foaming occurred with the addition of sulfuric acid and stirring became impossible, making it impossible to obtain a uniform foam. A phenol foam was produced. In some cases, foaming occurred with the addition of sulfuric acid, making stirring impossible.

In addition, the pH of the foam is 51! 100 f of distilled water was added to 0.5 t of the foam cut into Il squares, and the mixture was stirred for 6 hours.The pH value of the mouth fluid was measured with a pH meter, which was defined as the pH of the foam.

In addition, as a corrosion test, swing corrosion
Corrosion loss of mild steel (SPCC, cold rolled plate) was measured using a tester (manufactured by Yamazaki Seiki ■).

The swing seagull corrosion tester is a device that accelerates corrosion by creating a surface that comes in contact with water and paper, and can provide extremely reproducible data.

A sample person with steel plates 2a, 2b (150XIOOXlm) and 2c, 2d (10XIOOXlm) fixed on both sides of a 100X100X20 gourd foam 10 with rubber bands 3 as shown in Figure 2 is heated with deionized water 4 as shown in Figure 2.
Attach it to the container 5 containing 350 al/, and slowly move the container 5 while flowing air at a constant flow rate (4 times/day).
and swing it 90°. The E portion of the sample is always in water, the F portion is always in air, and the G and H portions are submerged in water or exposed to air. After testing at 50℃ for 20 days, the rust on the steel plate was eluted with a 10% hydrochloric acid aqueous solution, washed with water, dried, and weighed. The corrosion area reduction between the liquid contact surface and the foam contact surface was determined. The degree of corrosion was determined.

In addition, the corrosion reduction of the liquid contact surface is As, the corrosion loss of the foam contact surface is It was calculated as

(Margin below)

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a sample for corrosion testing, and FIG. 2 is a sectional view of the equipment for corrosion testing. Patent Applicant Mitsubishi Yuka Co., Ltd. Agent Patent Attorney Masahisa Hase Patent Attorney Takashi Yamamoto Figure 1 Figure 2 90"Swine 7

Claims (3)

[Claims] (1) In a method of manufacturing a resol type phenolic resin foam by blending a blowing agent, a foam stabilizer, a curing agent, and a neutralizing agent with a liquid resol type phenolic resin, barium metaborate is blended as a neutralizing agent. A method for producing a phenolic resin foam, characterized by: (2) The method according to claim 1, wherein the neutralizing agent is used in an amount of 1 to 30 parts by weight per 100 parts by weight of the resol type phenolic resin. (3) The manufacturing method according to claim 1, wherein the curing agent is sulfuric acid.