JPH025777B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a foam, and more particularly, to a method for producing a phenolic resin foam that is uniform, has high mechanical strength, and has excellent flame retardancy and heat insulation properties. Foamed plastic materials are widely used industrially, and are particularly useful as insulation materials for buildings, cushioning packing materials for product packaging, and the like. In addition to mechanical strength, recent performance requirements for building materials include flame retardancy and heat insulation. Among plastic materials, phenolic resin has the highest flame retardancy, and it is necessary to foam it to give it insulation properties.
Conventional foamed phenolic resin has a density of 30 to 60 kg/
^m3 , its mechanical strength is also low, and furthermore, it does not have sufficient fire resistance required as a building material. Therefore, it becomes necessary to add a large amount of inorganic filler to the foamed phenolic resin, which improves fire protection and fire resistance while also leading to cost reduction. By the way, it is known that foamed phenolic resin can be obtained directly from a phenolic resol and an acidic curing agent without adding a gas-generating additive, but depending on this method, it has reasonable dimensions, Since it is difficult to obtain products of consistent quality that are reproducible, methods have been developed in which chemicals are added to a mixture of a phenolic resol and an acidic curing agent to generate or disperse a foaming gas. Among these methods, it is common to add low-boiling liquid hydrocarbons and other organic compounds, but such volatile compounds are expensive, dangerous to handle, and do not remain in the product. It has a negative effect on flame resistance.
There is also a method in which the reaction between a liquid phenolic resol and a strongly acidic curing agent is carried out in the presence of fine inert, insoluble granular solids uniformly dispersed therein (Japanese Patent Application Laid-open No.
55-43189) has also been proposed, but adding a large amount of filler to the phenolic resin worsens dispersion, increases the viscosity of the mixture, and reduces fluidity during pouring into a mold or shortens the catalyst. It becomes difficult to stir for a long time. The present invention was made in view of the current situation, and its purpose is to create a phenolic resin-based material that uses a large amount of filler, is uniform, has high mechanical strength, and has excellent flame retardancy and heat insulation properties. An object of the present invention is to provide a method for producing a foam. The present invention has the following configuration to achieve the above object. That is, the method for producing the foam of the present invention involves organic vaporizable foaming of a foamable composition containing a liquid phenolic resol whose reactivity is 320 to 24 seconds as measured by curing time, a strongly acidic curing agent, and a filler. In producing a foam by foaming with an agent, about 1 to 10 parts by weight of lignin sulfonate (calculated as a 40% by weight aqueous solution) is added to the foamable composition based on 100 parts by weight of the phenolic resol. The foaming agent is dispersed in the composition and foamed while suppressing the curing reaction. The present inventors have conducted intensive studies on a method of adding a large amount of filler to foamed phenolic resin while preventing a decrease in dispersibility and an increase in viscosity. The present invention was based on the discovery that adding a specific amount of an aqueous solution of lignin sulfonate to a foamable composition containing a hardener and a filler improves the dispersion of the filler and reduces the viscosity of the slurry. It has been reached. In addition to the above-mentioned effects, lignin sulfonate has the effect of suppressing the curing reaction of liquid phenolic resol and delaying the reaction time, suppressing local rapid reactions in solid areas where dispersion is insufficient. , plays the role of a foaming retardant that slows down the foaming speed, makes full use of the foaming effect of the organic vaporizable foaming agent, allows easy density adjustment, and provides a uniform foam. The liquid phenolic resol in the present invention is
A suitable reactivity is 320 to 24 seconds as measured by curing time. The above reactivity (acid curing time of the resin) is measured by the following method. That is, after putting 10 g of resin at 25°C and 1.5 g of 66.7% by weight para-toluene sulfonic acid solution into a test tube and stirring,
The sample was placed in an atmosphere of 55°C±1°C, and the time (seconds) from the addition of para-toluenesulfonic acid until the completion of curing was measured, and this time was used as a guideline for reactivity. Note that the end of curing is determined by the limit at which the curing temperature rises (for example, 90° C.) due to heat generation accompanying curing. Such liquid phenolic resols are commercially available, such as PL-
3812B, PL-3812C and PL-3812D, etc., and their characteristics are shown in the table below.

[Table] The lignin sulfonate (usually sodium salt) used in the present invention is a type of anionic surfactant, has excellent dispersibility, and is inexpensive, and is usually applied as an approximately 40% by weight aqueous solution. The appropriate blending ratio is about 1 to 10 parts by weight per 100 parts by weight of liquid phenolic resol; if it is less than 1 part by weight, it will not have any effect, and if it exceeds 10 parts by weight, curing will be significantly delayed. Undesirable. (See experimental results below) In the present invention, a small amount of surfactant (about 100 parts by weight of liquid phenolic resol) is added.
By adding (0.01 to 1 part by weight), the foam cell size can be reduced. The type of surfactant is not particularly limited, and for example, commercially available products such as Tween 80 manufactured by Kao Atlas Co., Ltd. can be used. In addition, the organic vaporizable blowing agent in the present invention has a boiling point of
It is appropriate to use a blowing agent of about 20 to 60°C, and examples of such blowing agents include Freon 11 and
Commercially available fluorine-based compounds such as 113 (manufactured by Mitsui Fluorochemical Co., Ltd.) are suitable, but are not particularly limited.
The amount used is suitably about 1 to 15 parts by weight per 100 parts by weight of liquid phenolic resol. Further, the filler in the present invention is not particularly limited as long as it is insoluble and inert in the reaction mixture, and examples thereof include gypsum hemihydrate (plaster), talc, wood flour, mineral fiber, glass powder, diatomaceous earth, and aluminum hydroxide. Various powders can be applied, such as glass beads, glass balloons, calcium carbonate, clay, fly ash, shirasu balloons, perlite, vermiculite, metal powders and crushed plastics.
In addition, the amount used is
Approximately 20 to 300 parts by weight per 100 parts by weight, preferably
A suitable amount is 25 to 100 parts by weight. Furthermore, suitable strong acid curing agents in the present invention include inorganic acids such as sulfuric acid, hydrochloric acid and phosphoric acid, and strong organic acids such as paratoluenesulfonic acid and paraphenolsulfonic acid. Weak acids such as acetic acid and propionic acid are generally unsuitable.
These acids are dissolved in a suitable solvent and used, for example, as an aqueous solution. The amount of these curing agents to be blended varies depending on the temperature of the mixture of liquid phenolic resol and curing agent before the start of the exothermic curing reaction and the reactivity of the resol, but usually for 100 parts by weight of the resol,
About 5 parts by weight or more, for example, as shown in the examples below, the resol is made by Gunei Chemical Industry Co., Ltd., PL.
-3812C or D, and when a 66.7% by weight aqueous solution of para-toluenesulfonic acid is used as the curing agent, it is appropriate to use 10 to 20 parts by weight based on 100 parts by weight of the resol. In a typical manufacturing method for the foam of the present invention, a liquid phenolic resol is first adjusted to a temperature of around 20°C, an aqueous solution of lignin sulfonate is added thereto, and an organic vaporizable blowing agent and a filler are added. They may be added, mixed, placed in a suitable mold, and foamed and cured in an atmosphere at a temperature of usually 50 to 80°C. An important feature of the invention, as mentioned above, is the use of lignosulfonate. In order to investigate the effect of adding lignosulfonate, the present inventors investigated the amount of lignosulfonate added and the reaction (starting of foaming,
The relationship between curing completion time and foaming ratio was investigated and the results are shown below. As the liquid phenolic resol, the above-mentioned PL-3812D was used, and the amount of a 40% by weight aqueous solution of ligninsulfonic acid sodium salt was varied with respect to 100 parts by weight of the resol, and in addition, surfactant (the above-mentioned Tween 80 ), 9 parts by weight of a foaming agent (Freon 113), 50 parts by weight of a filler (talc: gypsum hemihydrate = 2:1 weight ratio) and 10 parts by weight of a hardening agent (para-toluenesulfonic acid), The reaction was carried out at a compounding temperature of 20°C and an ambient temperature of 60°C. Foaming was done by free foaming using a cup. That is, FIG. 1 is a graph showing the relationship between the addition ratio of lignin sulfonate and the foaming start time and hardening end time, where A is the foaming start time;
B indicates the curing completion time. As is clear from the graph in Figure 1, the curing time increases as the proportion of lignin sulfonate added increases, and the amount added is approximately 1 part by weight per 100 parts by weight of phenolic resol.
The reaction is sufficiently suppressed at about 4 parts by weight, and a uniform and relatively dense foam can be obtained.
In addition, Figure 2 shows the addition ratio of lignin sulfonate and foaming ratio (ratio of solid raw material density to foam density).
FIG. As is clear from Fig. 2, as the addition ratio of lignin sulfonate increases, the expansion ratio gradually decreases.
Since the expansion ratio decreases very slowly from around 10% by weight (approximately 10 parts by weight per 100 parts by weight of phenolic resol), there is no point in adding any more lignin sulfonate. Therefore, in consideration of Figures 1 and 2, in order to fully exhibit the foaming effect using an organic vaporizable foaming agent, the addition ratio of the lignin sulfonate should be 100% of the phenolic resol. It has been found suitable to use about 1 to 10 parts by weight. As described above, according to the present invention, by adding lignin sulfonate to the liquid phenolic resol, the dispersibility becomes good even when a large amount of filler is used, and the effects listed below are achieved. can get. (a) The foam cells are uniform and the cell size is 5 μm to 8 mm.
You can choose from a wide range of options. (b) Foams from low density to high density (30 to 800 Kg/m ³ ) can be easily manufactured. (c) Foaming time can be controlled freely. (d) Flyability, which is a drawback of phenolic foams, is extremely low. (e) Higher strength than general phenolic foams. (f) Higher flame retardancy than general phenolic foams. Next, the present invention will be explained with reference to examples, but the present invention is not limited to these in any way.
Note that parts in the text indicate parts by weight. Example 1 100 parts of liquid phenolic resol (manufactured by Gunei Kagaku Kogyo Co., Ltd., PL-3812D) was adjusted to 20°C, and 40% by weight of ligninsulfonic acid sodium salt was added to it.
Aqueous solution (manufactured by Sanyo Kokusaku Pulp Co., Ltd., Vaniol AOL
-50) 1.5 parts were added, and further 10 parts of Freon-113 (manufactured by Mitsui Fluorochemical Co., Ltd.) was added. Then,
Hemihydrate gypsum (plaster) (manufactured by Nitto Gypsum Co., Ltd., α-1)
33 parts and 17 parts of talc (manufactured by Matsumura Sangyo Co., Ltd., HS) were added and thoroughly mixed. Next, 10 parts of a 66.7% by weight aqueous solution of para-toluenesulfonic acid was added, and about 500 g of the resulting mixture was placed in a wooden mold 30 cm square and 3 cm high, and foamed and cured at 60°C. As a result, a uniform foam with a foaming ratio of 10 times, a density of 153 kg/m ³ and a foam cell size of 7 mm was obtained. In addition, it did not have the powdering property that general foamed phenolic resins have. When the thermal conductivity was measured,
It was 0.054Kcal/mHr℃. Example 2 Example 2 100 parts of liquid phenolic resol (manufactured by Gunei Kagaku Kogyo Co., Ltd., PL-3812D) was adjusted to 20°C, and 40% by weight of sodium lignin sulfonate was added to it.
Aqueous solution (manufactured by Sanyo Kokusaku Pulp Co., Ltd., Vaniol AOL
-50) 1.0 part and surfactant (manufactured by Kao Atlas Co., Ltd.,
Add 1 part of Tween 80) and further Freon 113
(manufactured by Mitsui Fluorochemical Co., Ltd.) 10 parts were added. Next, hemihydrate gypsum (plaster) (manufactured by Nitto Gypsum Co., Ltd.,
α-1) 33 parts and talc (manufactured by Matsumura Sangyo Co., Ltd., HS)
17 parts were added and thoroughly mixed. Next, add 10 parts of a 66.7% by weight aqueous solution of para-toluenesulfonic acid,
Approximately 500 g of the obtained mixture was placed in the same wooden mold as in Example 1, and placed in an atmosphere at 60°C to foam and harden. As a result, the density was 159Kg/m ³ and the foam cell size was
A uniform foam of 10 μm was obtained. This foam also had no pulverizability. Moreover, when its thermal conductivity was measured, it was 0.055 Kcal/mHr°C. Example 3 100 parts of liquid phenolic resol (manufactured by Gunei Kagaku Kogyo Co., Ltd., PL-3812D) was adjusted to 25°C, and 40% by weight of sodium lignin sulfonate was added thereto.
Aqueous solution (manufactured by Sanyo Kokusaku Pulp Co., Ltd., Vaniol AOL
-50) 1.5 parts and surfactant (manufactured by Kao Atlas Co., Ltd.,
Added 0.1 part of Tween 80) and further Freon 113
(manufactured by Mitsui Fluorochemical Co., Ltd.) 10 parts were added. 33 parts of hemihydrate gypsum (plaster) (manufactured by Nitto Gypsum Co., Ltd.) and 17 parts of talc (manufactured by Matsumura Sangyo Co., Ltd., HS) were added and thoroughly mixed. Next, 10 parts of a 66.7% by weight aqueous solution of para-toluenesulfonic acid was added to this, and about 500g of the resulting mixture was placed in the same wooden mold as in Example 1.
It was placed in an atmosphere at ℃ and allowed to foam and harden in a wooden mold. As a result, the density was 151Kg/m ³ and the foam cell size
A uniform foam of 0.2 mm was obtained. This foam also had no pulverizability. Comparative Example 1 (without filler) 100 parts of liquid phenolic resol (manufactured by Gunei Chemical Industry Co., Ltd., PL-3812D) was adjusted to 20°C, and 40% by weight of sodium lignin sulfonate was added to it.
Aqueous solution (manufactured by Sanyo Kokusaku Pulp Co., Ltd., Vaniol AOL
-50) 1.5 parts were added, and further 5 parts of Freon 113 (manufactured by Mitsui Fluorochemical Co., Ltd.) were added. Next, 10 parts of a 66.7% by weight aqueous solution of para-toluenesulfonic acid was added, and about 500 g of the resulting mixture was placed in the same wooden mold as in Example 1, and placed in an atmosphere at 60°C to foam and harden. The foaming ratio was 20 times, and it had powderability. Comparative Example 2 (No foaming agent added) 100 parts of liquid phenolic resol (manufactured by Gunei Chemical Industry Co., Ltd., PL-3812D) was adjusted to 20°C, and 40% by weight of sodium lignin sulfonate was added to it.
Aqueous solution (manufactured by Sanyo Kokusaku Pulp Co., Ltd., Vaniol AOL
-50) 1.5 parts were added. Next, 33 parts of hemihydrate gypsum (plaster) (manufactured by Nitto Gypsum Co., Ltd., α-1) and 17 parts of talc (manufactured by Matsumura Sangyo Co., Ltd., HS) were added. Next, a 66.7% by weight aqueous solution of para-toluenesulfonic acid
About 500 g of the resulting mixture was placed in the same wooden mold as in Example 1, and placed in an atmosphere at 60°C to foam and harden. As a result, no foaming occurred (foaming ratio: 2 times or less), and a curing reaction was observed. Comparative Example 3 (No addition of lignin sulfonate) 100 parts of liquid phenolic resol (manufactured by Gunei Chemical Industry Co., Ltd., PL-3812D) was adjusted to 20°C, and gypsum hemihydrate (plaster) (manufactured by Nitto Gypsum Co., Ltd.) was added to it. ,α
-1) 33 parts and talc (manufactured by Matsumura Sangyo Co., Ltd., HS) 17
5 g of Freon 113 (manufactured by Mitsui Fluorochemical Co., Ltd.) was added. Next, 10 parts of a 66.7% by weight aqueous solution of para-toluenesulfonic acid was added, and about 500 g of the resulting mixture was placed in the same wooden mold as in Example 1 and placed in an atmosphere at 60°C to foam and harden.
As a result, a foam was formed, but the cells were not round, the cell size was not uniform, and the foaming ratio was 7.
It was twice as hot. Example 4 100 parts of liquid phenolic resol (manufactured by Gunei Kagaku Kogyo Co., Ltd., PL-3812C) was adjusted to 25°C, and 40% by weight of sodium lignin sulfonate was added thereto.
Aqueous solution (manufactured by Sanyo Kokusaku Pulp Co., Ltd., Vaniol AOL
-50) 3 parts and surfactant (manufactured by Kao Atlas Co., Ltd.,
Add 0.5 part of Tween 80) and further Freon 113
(manufactured by Mitsui Fluorochemical Co., Ltd.) 10 parts were added. Next, hemihydrate gypsum (plaster) (manufactured by Nitto Gypsum Co., Ltd.,
α-1) 8 parts and talc (manufactured by Matsumura Sangyo Co., Ltd., HS)
17 parts were added and thoroughly mixed. Next, add 10 parts of a 66.7% by weight aqueous solution of para-toluenesulfonic acid,
Approximately 150 g of the obtained mixture was placed in a mold of 22 cm square and 3 cm high whose inner surface was treated with Teflon, and placed in an atmosphere at 60° C. to foam and harden. As a result, a uniform foam with a density of 97 Kg/m ³ and a foam cell size of 0.1 mm was obtained. This foam also had no pulverizability. Example 5 100 parts of liquid phenolic resol (manufactured by Gunei Kagaku Kogyo Co., Ltd., PL-3812C) was adjusted to 25°C, and 40% by weight of sodium lignin sulfonate was added thereto.
Aqueous solution (manufactured by Sanyo Kokusaku Pulp Co., Ltd., Vaniol AOL
-50) 2 parts and surfactant (manufactured by Kao Atlas Co., Ltd.,
Add 0.1 part of Tween-80) and add Freon.
113 (manufactured by Mitsui Fluorochemical Co., Ltd.) 7 parts and Freon
11 (manufactured by Mitsui Fluorochemical Co., Ltd.) was added.
Next, hemihydrate gypsum (plaster) (manufactured by Nitto Gypsum Co., Ltd.,
α-1) 66 parts and talc (manufactured by Matsumura Sangyo Co., Ltd., HS)
34 parts were added and thoroughly mixed. Next, 10 parts of a 66.7% by weight aqueous solution of para-toluenesulfonic acid and 5 parts of a 50% aqueous solution of phosphoric acid were added, and the resulting mixture approx.
150g was placed in the same mold as in Example 4,
It was placed in an atmosphere at 60°C to foam and harden. As a result, a uniform foam with a density of 103 Kg/m ³ was obtained.
This foam also had no pulverizability. Comparative Example 4 (Resol curing rate outside the range of the present invention) 100 parts of liquid phenolic resol (manufactured by Gunei Chemical Industry Co., Ltd., PL-3812B) was adjusted to 20°C, and lignin sulfonic acid sodium salt was added to it. 40% by weight of
Aqueous solution (manufactured by Sanyo Kokusaku Pulp Co., Ltd., Vaniol AOL
-50) 4 parts and surfactant (manufactured by Kao Atlas Co., Ltd.,
Add 0.75 parts of Tween 80) and add Freon
113 (manufactured by Mitsui Fluorochemical Co., Ltd.) 10g and Freon
11 (manufactured by Mitsui Fluorochemical Co., Ltd.) was added.
Next, hemihydrate gypsum (plaster) (manufactured by Nitto Gypsum Co., Ltd.,
α-1) 200 copies and talc (manufactured by Matsumura Sangyo Co., Ltd., HS)
50 parts were added and thoroughly mixed. Next, 20 parts of a 66.7% by weight aqueous solution of para-toluenesulfonic acid was added, and about 500 g of the resulting mixture was placed in the same mold as in Example 4 and placed in an atmosphere at 60°C to foam and harden. As a result, a foam with a density of 280 Kg/m ³ but with non-uniform cell sizes was obtained. As explained above, according to the present invention, it is possible to produce a phenolic resin foam that uses a large amount of filler, is uniform, has high mechanical strength, and has excellent flame retardancy and heat insulation properties. can.

[Brief explanation of drawings]

FIG. 1 is a graph showing the relationship between the addition ratio of lignin sulfonate and the foaming start time and hardening end time, where A shows the reaction start time and B shows the hardening end time. Further, FIG. 2 is a plot diagram showing the relationship between the addition ratio of lignin sulfonate and the expansion ratio.

Claims (1)

[Claims] 1. To produce a foam by foaming a foamable composition containing a liquid phenolic resol, a strongly acidic curing agent, and a filler with a reactivity of 320 to 24 seconds as measured by curing time using an organic vaporizable foaming agent. About 1 to 10 parts by weight of lignin sulfonate (calculated as a 40% by weight aqueous solution) is added to the foaming composition based on 100 parts by weight of the phenolic resol, and the foaming agent is added while suppressing the curing reaction. A method for producing a foam, which comprises dispersing and foaming in the composition.