JPS59164343A - Production of phenol resin foam - Google Patents

Abstract

PURPOSE:To produce the titled foam having closed cells and a uniform, fine cell structure, by reacting a resol type phenolic resin, a blowing agent, a specified foam stabilizer and a hardener. CONSTITUTION:A blowing agent having a b.p. of -40-100 deg.C such as trichlorofluoromethane, 0.1-10pts.wt. polyalkylene glycol monoalkyl ether of the formula (wherein R1 is 1-4C alkyl; R2 is 2-4C alkylene; n is 1-3) as a foam stabilizer and a hardener such as p-toluenesulfonic acid are mixed with 100pts.wt. resol type phenolic resin obtd. by reacting phenol with formaldehyde. The mixture is vigorusly stirred to expand the resin. EFFECT:A foam having excellent heat resistance, heat insulating properties and flame retardance and useful as building material can be obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a phenolic resin foam having closed cells and a uniform fine cell structure.

Phenolic resin foams are used for various purposes due to their excellent properties such as fire resistance and heat insulation. Generally, there are two methods for producing phenolic resin foams: a method using a mixture of a Novo 2 type phenolic resin and hexamethylenetetramine;

The present invention relates to a method for producing a phenolic resin foam using a resol-based phenolic resin.

V-sol-based phenolic resin foams can be produced by reacting a phenolic compound and an aldehyde compound, generally under controlled reaction conditions and in the presence of a controlled excess of the aldehyde compound. Foaming is performed by mixing a certain amount of a foaming agent, a foam stabilizer, and an acidic curing agent with a resol type phenolic resin, and applying a temperature of room temperature or 40 to 120°C.

As the phenol compound or aldehyde compound used in the production of the resol-based phenolic resin, various compounds can be used. Phenolic compounds include both phenol and its congeners such as cresol and xylenol or mixtures of these compounds. Aldehyde compounds that react with phenolic compounds include, for example, formaldehyde, acetaldehyde, furfural, and other aldehydes and mixtures of these compounds. Additionally, aldehyde-producing compounds can also be used, such as paraformaldehyde,
Compounds that decompose to formaldehyde such as hexamethylenetetramine, methylol, trioxane, tetraoxymethane and others and mixtures of these compounds can also be used. The reaction between phenolic compounds other than phenol and aldehydes other than formaldehyde or its complex forms is slower than the reaction between phenol and formaldehyde. Therefore, in the present invention, it is preferable to use a resol type phenol resin in which phenol and formaldehyde are reacted.

The blowing agent that can be used in the present invention has a boiling point of about -40
C to 1.00 C, polyhalogenated saturated fluorocarbons, halokenated hydrocarbons, especially fluorocarbons, hydrogen chloride or mixtures thereof.

Some examples of a large number of suitable blowing agents include chlorinated and fluorinated hydrocarbons such as chloroform, di-methylene, trichlorofluoromethane, tetrafluoromethane, 1.1.2-1lichloro-1.2 .2-) IJ fluoroethane: monochlorodifluoromethane; dichlorodifluoromethane: 1.1-cyclo1. ．． 2.2.2
-Tetrafluoroethane: 1,2-dichloro-3,,1
,2,2-tetrafluoroethane:1.1.1-1lichloro-2°2,. 2-) Lifluoroethane: 1.2-difluoroethane: Promotrifluoroethane: 1.1°2.2-tetrachloro-1,2-difluoroethane: 1
．． 11.2-tetrachloro-2,2-difluoroethane or mixtures of these compounds.

The foam stabilizers used in the present invention include surfactants such as silicone/ethylene oxide/propylene oxide copolymers, alkoxycycnes, polysilylphosphonates, polydimethylsiloxanes, and polydimethylsiloxane-polyoxyalkylene copolymers. Can be used.

The curing agents used in this paper include mineral acids such as sulfuric acid, hydrochloric acid, and phosphoric acid, and organic acids such as P-toluenesulfonic acid and phenolsulfonic acid. By shifting the pH of the alkaline or neutral resol type phenolic resin to the acidic side at once, combination begins immediately and foaming begins in the presence of the foaming agent.

The phenolic resin foam thus obtained is typically believed to have 40-100% open cells. This is caused by destruction of the cells and cracks in the center of the foam due to eyes, voids, etc.

As an improvement on the above problems, JP-A-56-304
There are 38. This involves adding N-methyl-2-pyrrolidone to obtain uniform cells.

However, the phenol resin foam obtained in the presence of N-methyl-2-pyrrolidone had a slight effect of making the cells uniform and fine, but had a large number of continuous cells.

Therefore, the present inventors conducted intensive research to obtain a phenolic resin foam having closed cells and a uniform fine cell structure.As a result, the inventors mixed polyalkylene glycol monoalkyl ether as a foam stabilizer in a specific ratio. By this,
A phenolic resin foam, which is the object of the present invention, was obtained.

That is, the present invention provides a resol type phenolic resin, a blowing agent,
When producing phenolic resin foam from foam stabilizers, curing agents, etc., polyalkylene glycol monoalkyl ether is used as a foam stabilizer to resol type phenolic resin 100.
This is a method for producing a phenolic resin foam, characterized in that 0.1 to 10 parts by weight are added to each part by weight.

The polyalkylene glycol monoalkyl ether used in the present invention is represented by the following structural formula.

R1-0,000R2-0-)-01 (R1: Alkyl group R2: Alkylene group (C number 1-4
) (O number 2-4) n: 1-3 For example, ethylene glycol monomethyl ether, propylene glycol monomethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monomethyl ether, propylene glycol monobutyl ether, triethylene glycol monomethyl Examples include ether and butylene glycol monomethyl ether. Moreover, it is not limited to one type, and two or more types may be used in combination.

It may also be used in combination with other commonly used foam stabilizers.

The amount added is 0.1 to ]-0 parts by weight, preferably 0.5 to
5 parts by weight is good. If it exceeds 10 parts by weight, the foam will have a closed-cell fine cell structure, but the mechanical strength, heat resistance,
This is not preferred because it reduces fire resistance. When the amount is less than 0.1 part by weight, a foam having a uniform fine cell structure of closed cells cannot be obtained.

It is preferable to use the polyalkylene glycol monoalkyl ether of the present invention by mixing it into a resol-based phenol resin in advance. In order to mix and foam the resol type phenol resin and other raw materials into which the polyalkylene glycol monoalkyl ether is mixed, any method may be used as long as the reaction mixture can be mixed uniformly.

For example, 1,500 to 10. It can be obtained in commercial mixing equipment such as OOOrpm gear type or bottle type mixers.

The characteristics of the phenolic resin foam obtained by the present invention are as follows.

1) It has a higher closed cell ratio than conventional resol-based phenolic resin foams and exhibits excellent heat insulation performance.

2) The center of the foam has no holes or voids, and has a uniform cell structure, so the mechanical strength of the foam is high.

3) It has little effect on foam hair growth and curing, and can be foamed using normal methods.

4) It has the same flammability, low smoke emission, and heat resistance as conventional phenolic resin foam.

As described above, the resol-based phenolic resin foam according to the present invention has 41 closed cells, a uniform fine cell structure, and has excellent heat insulation properties, heat resistance, and flame retardance, and therefore can be widely used in the field of building materials.

Next, the present invention will be specifically explained with reference to examples, but the present invention is not limited to these examples.

The reaction mixture shown in Implementation Relays 1 to 6 glp was weighed into a 16 polyethylene beaker, and stirred vigorously for 10 to 30 seconds with a mixer (rotation speed 8000 rpm) at room temperature (20 to 25°C).
The mixture was heated to 0° C. to 80° C. and foamed in an aluminum mold with an open top, and cured in an oven at 80° C. to 120° C. for about 10 minutes to obtain a resol-based phenolic resin foam. After two weeks of dehydration at room temperature, the foam properties were measured.

Compared to Comparative Example-1 in which a foam stabilizer was used, the closed cell ratio was higher and the thermal conductivity was lower. Visual inspection revealed that there were no holes or large voids in the center of the foam, and it had a uniform and fine cell structure.

Examples 7 to 9 Resol type phenolic resin foams were obtained using the mixtures shown in Table 1 in the same manner as in Example 1.

The closed cell ratio was higher than that of ratio@cry-2. Also, 1
The heat resistance at 50°C was also good. Visual inspection revealed that the cell structure was uniform and fine.

Comparison row-1 The resol-based phenolic resin foam obtained from the mixture shown in Table-1 not only had a lower closed cell/foam ratio than Examples 1 to 6, but also had large cells as a result of visual inspection. The structure was heterogeneous.

Comparison and 20-2 The resol type phenolic resin foam obtained from the mixture shown in Table 1 not only had no closed cells at all, but also
The cell structure was also non-uniform.

Comparative Example 3 As a result of using N-methyl-2-pyrrolidone as a foam stabilizer, the cell structure became uniform and fine, but there was no increase in closed cells.

Phenol steel fat-A: Phenol, formaldehyde (resol type phenol) resin with a viscosity of 2500 cp/25°C and a solid content of 75 cm Phenol resin-B A viscosity of 1000 cp/25°C and a solid content content Phenol, formaldehyde (resol type phenol) with a ratio of 15% Foam stabilizer: Silicone surfactant (Toray Silicone fisH-193) Polyalkylene glycol monoalkyl ether - A: Diprobylene glycol monomethyl ether Polyalkylene glycol monoalkyl Ether B: Globylene glycol monomethyl ether Polyalkylene glycol monoalkyl ether = Cyclopylene glycol monobumel ether Polyalkylene glycol monoalkyl ether D: Ethylene glycol monobutyl ether Foaming agent: Trichlorotrifluoroethane Hardening agent: 65%
Phenolsulfonic acid aqueous solution foam density: J Engineering 5A-
Compressive strength measured by 9514: Measured by J-K5A-9514 Brittleness: The smaller the value measured by ASTMO-421, the less brittle the 7ohno.

Closed cell ratio: Measured according to ASTM D-2856 Thermal conductivity: Measured according to J Engineering 5A-9514 External smoke count: 220
J Engineering 5A-132 using the test piece of X220X30
According to the surface test for grade 2 flame retardancy (No. 1), the smaller the measured value, the less the amount of smoke emitted.

Heat resistance: 100X], 0OX50 Test specimens were left in an open environment at 150°C for 24 hours to measure deformation, cracks, etc. The patent applicant is characterized by having little deformation and no cracks.

Claims (1)

[Claims] When producing a phenolic resin foam from a resol type phenolic resin, a blowing agent, a foam stabilizer, a curing agent, etc., polyalkylene glycol monoalkyl ether is added as a foam stabilizer to 100 parts by weight of the resol type phenolic resin.
A method for producing a phenolic resin foam, the method comprising adding 1 to 10 parts by weight.