JPH03106947A - Production of phenolic rein foam - Google Patents

Abstract

PURPOSE:To produce a phenolic resin foam improved in heat resistance, etc., without using any fluorohydrocarbon, pentane or the like by mixing a resol phenolic resin with a specified amount of liquefied carbon dioxide as a blowing agent, a foam stabilizer and an acid curing agent to expand and cure the resin. CONSTITUTION:A phenol (e.g. phenol) is reacted with an aldehyde (e.g. formaldehyde) in the presence of a basic catalyst, and the reaction mixture is concentrated by dehydration to obtain a resol phenolic resin (A) of a resin matter content of 60-90% and a viscosity of 1500-8000cP at 25 deg.C. 100 pts.wt. component A is mixed with 0.3-15 pts. vol., per pt. vol. component A, liquefied carbon dioxide (B) as a starting material for a blowing agent, 0.5-10 pts.wt. foam stabilizer (C) (e.g. polyoxyethylene sorbitan monopalmitate) and 5-40 pts.wt. acid curing agent (D) (e.g. phenol sulfonic acid) to foam and cure the resin.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention has heat resistance, heat insulation, flame retardancy, and water resistance, making it useful as a building material for wall materials, ceiling materials, furniture, etc. [Conventional technology] Phenolic resin foam is lightweight and has excellent flammability, heat resistance, and mechanical strength compared to thermoplastic resin foam. Excellent, widely used in the field of building materials and as a material for furniture, etc. The manufacturing method uses resol resin as a raw material and trichloromonofluoromethane (Freon-11) as a blowing agent. Trichlortrifluoroethane (Freon-113). Pentane etc. were mainly used. However, Freon-11 and Freon-113 have extremely excellent properties as foaming agents, are harmless to the human body, and are not flammable.
Although they are non-flammable and safe foaming agents from a process standpoint, it has been discovered that these fluorocarbons destroy the ozone layer that surrounds the earth and accelerate the destruction of the earth's environment, leading to a reduction in their usage and even a ban on their use. The need for this is becoming increasingly important. Furthermore, although pentane does not cause the problem of global environmental destruction unlike fluorocarbons, it is a flammable hydrocarbon gas that poses an extremely high risk of explosion or fire if it leaks, and the explosive range of pentane is It is well known that even a small amount of gas falls within this range, and that it is a gas that has a higher specific gravity than air, so it tends to accumulate in low places and poses a safety problem. As other foaming agents, azo compounds that release nitrogen gas when heated have been used, but these compounds are expensive, require large amounts to increase the foaming ratio, and are difficult to foam. It has been mainly used for foams with low expansion ratios because it is necessary to maintain the temperature at or above the decomposition temperature of the compound for a long time. [Problem to be Solved by the Invention J] The present invention creates a foam with a relatively high magnification in a safe manner without using fluorocarbons, which cause air pollution, and without using flammable and explosive gases such as bentane. Using a blowing agent that can be operated, the heat resistance, flame retardance, heat insulation properties, and
The purpose of this project is to develop a method for manufacturing phenolic foam with excellent characteristics such as lightness. [Means for Solving the Problem] As a result of various studies to achieve the above object, the present invention has been made based on the following:
When producing a phenolic resin foam by mixing and curing a resol type phenolic resin, a blowing agent, a foam stabilizer, and a D hardening agent, liquefied carbon dioxide is added to 1 part by volume of the phenolic resin as a starting material for the blowing agent. Using .3 to 15 parts by volume,
We have developed a method to produce phenolic resin foam. In particular, 0.3 to 15
Each volume of liquefied carbon dioxide is separately and continuously fed into a phenolic resin foaming machine, and the phenolic resin foaming mixture is discharged while rapidly and uniformly mixed, and then cured in a mold, thereby making it safe and free from air pollution. We have discovered that it is possible to produce a phenolic resin foam completely free of phenolic resin. Here, examples of phenols that can be used in the resol type phenolic resin include phenol, cresol, xylenol, etc., which are usually used as raw materials for producing phenolic resin, but among these, phenol, Mecclesol is particularly preferred. These phenols are used not only individually. These may be mixed with each other, or may be used in combination with 0-cresol, p-cresol, bisphenol, etc. Examples of aldehydes include formaldehyde. Paraformaldehyde, polyoxymethylene, trioxyxane, etc. can be used. Both are reacted in the presence of a basic catalyst and dehydrated and concentrated to obtain a resol type phenol resin, with a resin solid content of 60 to 90% and a viscosity of 1.500 to 8.000 c.
It is convenient to use p s / around 25℃, and if the concentration is high, add a small amount of water, alcohol, acetone,
Adjust concentration and viscosity by appropriately diluting with ester, plasticizer, etc. The foam stabilizer used in the present invention is almost the same as that used when using Freon foaming agents. Silicone type: Ethylene oxide-brobylene oxide copolymer: Surfactants such as sorbitan, alkylphenol, or polyoxyalkylene adducts such as castor oil can be used. These can be used alone or in combination, but The amount is 0.00 parts by weight per 100 parts by weight of phenolic resin. It is 5 to 10 parts by weight. The acid curing agent is also the same as that used when using a fluorocarbon blowing agent, such as balatoluene sulfur acid m. Use a strong acid such as phenolsulfonic acid. The amount added is preferably 5 to 40 parts per 100 parts by weight of phenolic resin. The appropriate amount of liquefied carbon dioxide used as a starting material for the blowing agent is 0.3 to 15 parts by volume per 1 part by volume of phenolic resin. A good foam cannot be obtained outside this range. Phenolic resin foam can be manufactured using almost the same method as when using fluorocarbons. That is, a resol-type phenolic resin containing a foam stabilizer with adjusted resin solid content and viscosity, an acid curing agent, and liquefied carbon dioxide are each supplied to a mixer (mixing head) using quantitative bombs attached to the phenolic resin foaming machine. Mixing head screw is 1.000-10.00
The foam is rotated at a high speed of 0 rpm, and these raw materials are instantly and uniformly mixed and extruded from the foaming machine. The phenolic resin foam of the present invention is often used as a composite material with wood, metal, other synthetic resin, etc., rather than being used as it is. Therefore, the expansion rate of the foam also varies depending on the purpose, the material and strength of the composite material, and the expansion rate is relatively low (specific gravity 0.1
The foaming rate varies from 0.005 to high foaming rate (0.005). This foaming rate is adjusted by adjusting the amount of liquefied carbon dioxide injected. This foamed mixture is cured at a temperature of room temperature to 100°C, and the curing time is approximately 5 to 20 minutes. [Example] (Example 1) 2 kg of phenol was placed in a four-piece flask. 2.93 kg of 37% formaldehyde (formaldehyde/phenol dimolar ratio 1.7 mol) and 60 g of 20% sodium hydroxide as a catalyst were charged, and after reacting at 80°C for 3 hours, the pH was adjusted to 7.0 with 15% sulfuric acid. The water content in the resin was reduced to 5% or less by dehydration under reduced pressure. The obtained resol type phenolic resin has a resin solid content of 80%.
, viscosity 2500cps/25℃, weight average molecular weight 430
Met. Tween No. 1 for 10 parts by weight of this resol type phenolic resin. 40 (polyoxyethylene sorbitan monobalmitate) was mixed to prepare a foaming phenol resin. For foaming phenolic resin 1.6I2/min, 6
0.12 g/min of 5% phenol sulfonic acid was supplied to the mixer (mixing head) from the metering bomb of the phenol resin foaming machine, and 2 il/min of liquefied carbon dioxide was supplied to the mixer from a separate line at a screw rotation speed of 6.000 rpm. Instantly and uniformly mix the phenol resin, phenolsulfonic acid, and carbon dioxide, and discharge from the bottom of the mixer into a 50 cm width and 25 cm length. A certain amount of the resin was poured into a 4 cm high iron frame, and left in an open environment at 40°C for 5 minutes to complete foaming and curing to obtain a phenolic resin foam. The physical properties of the obtained phenolic resin foam are as follows: density 20K
g/m', water absorption 4.5 g/lookw, thermal conductivity 0.027 Kcal/mh'C, and the overall appearance was uniform. (Examples 2 to 6, Comparative Examples 1 to 2, Reference Example 1) The phenolic resin for resol type foaming obtained in Example 1 with added foam stabilizer was mixed with 1.6I2/min.65% phenol sulfonic acid 0.
Table 1 shows the results obtained by supplying liquefied carbon dioxide at a rate of l2j2/min and varying the amount of liquefied carbon dioxide supplied and the rotational speed of the mixing head screw. For reference, the conditions for obtaining a product almost the same as the example of the present invention using Freon-113 are shown as Reference Example 1. (See margins below) [Effects] Trichlormonofluoric methane (Freon-11), which was conventionally used as a blowing agent. }Lichlortrifluroethane (CFC-113) is said to destroy the ozone layer and pollute the earth's environment, and there are calls for its usage to be limited or banned, and the development of a manufacturing method that does not use CFCs has been called for. It was requested. On the other hand, there is a foam production method that uses bentane as a blowing agent without using CFCs, but this has the risk of explosion.
There was a safety issue.

Claims (2)

[Claims] (1) In producing a phenolic resin foam by mixing and curing a resol-type phenolic resin, a blowing agent, a foam stabilizer, and an acid curing agent, liquefied carbon dioxide is used as a starting material for the blowing agent and 1 part by volume of the phenolic resin is used. A method for producing a phenolic resin foam, characterized in that 0.3 to 15 parts by volume are used. (2) 0.3 to 15% per volume part of resol type phenolic resin containing foam stabilizer, acid curing agent and phenolic resin
Phenol resin foaming characterized by continuously and separately feeding volume parts of liquefied carbon dioxide to a phenol resin foaming machine, discharging a phenol resin foaming mixture while rapidly and uniformly mixing it, and then curing it in a mold. How the body is manufactured.