JPH0575778B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a phenolic resin foam having particularly improved brittleness resistance and heat insulation performance, and more particularly to a phenolic resin foam using unmodified starch. The phenolic resin foam according to the present invention is mainly used for exterior wall materials, interior wall materials, ceiling materials, roof base materials, floor base materials,
It is used as a thermal insulating material for buildings such as shutters, storage tanks, refrigerated warehouses, pipes, etc., but it is also used for a variety of other purposes. [Prior Art] In recent years, phenolic resin foams have become popular because they have excellent properties such as heat resistance, fire resistance, and low smoke emission that cannot be obtained with thermoplastic resin foams such as polystyrene resins, polyurethane resins, and polyethylene resins. , its usefulness has received a lot of attention. However, due to the inherent fragility of phenolic resin, the phenolic resin foam has poor surface brittleness (hereinafter referred to as flyability), and if it becomes powder or self-adhesively adheres to the surface material, the surface material may peel off. In addition, because the bubble membrane is weak and easily disintegrates, it has the disadvantage of poor insulation performance and a very large decline in insulation performance over time.
At present, there is a strong demand for improvement. One method for improving these problems is the method for producing a phenolic resin foam described in Japanese Patent Application Laid-open No. 59-219343. The gist of this prior art is that a liquid resol type phenolic resin initial condensate, a blowing agent, a surfactant,
In a method for producing a resol type phenolic resin foam using a foam stabilizer, an acidic curing agent, etc., acrylonitrile obtained by, for example, reacting starch with acrylonitrile or acrylic acid is added during mixing of all the components. such as grafted hydrolysates or acrylic acid graft compounds,
This is a method for producing a phenolic resin foam, characterized in that powder of a highly water-absorbing substance, which is a starch-based polymer, is added. However, although this method is said to be able to produce foams that are superior to conventional foams in terms of surface brittleness, adhesion, fire retardancy, etc., the insulation performance is still insufficient. It is difficult to say that this is the case, and no study has been made particularly from the viewpoint of suppressing the decline in heat insulation performance over time. [Problems to be Solved by the Invention] The present invention has been made in view of the problems of the prior art as described above, and its purpose is to solve the high flyability and Low insulation performance or
It is an object of the present invention to provide a phenolic resin foam that solves the drawback of deterioration in heat insulation performance over time and has excellent properties such as heat resistance, fire resistance, and low smoke emission without impairing it. [Means for solving the problem] In order to solve the above-mentioned drawbacks, the present inventors conducted intensive research and found that by adding unmodified starch when producing a phenolic resin foam. It was discovered that the resulting foam has very low flyability and excellent heat insulating performance with little deterioration over time, leading to the completion of the present invention. That is, the present invention provides a phenolic resin foam obtained by foaming and curing a blended composition containing a liquid phenolic resin, a blowing agent, an acidic curing agent, a foam stabilizer, and an unmodified starch as essential components, and which contains starch. The amount of the phenolic resin converted to solid resin content is 100
It is characterized by being 0.1 to 50 parts by weight. The unmodified starch used in the present invention includes, but is not limited to, corn starch, potato starch, and the like. In addition, the amount of unmodified starch added is 0.1 to 50 parts by weight of phenolic resin converted to solid resin content.
If it is less than 0.1 part by weight, the object of the present invention cannot be achieved and good flyability and heat insulation performance cannot be expected. Conversely, if it exceeds 50 parts by weight,
Curing properties become significantly worse. Furthermore, methods for blending unmodified starch in the present invention include a method in which it is blended at the manufacturing stage of the liquid phenolic resin, a method in which it is blended after the production, and a method in which it is blended at the time of preparing the foamable resin composition. Well, there are no particular limitations. Examples of the liquid phenolic resin according to the present invention include phenol, cresols such as o- or m- or p-cresol, xylenols such as 3,4- or 3,5-xylenol, and C such as p-tertiary leaf phenol. Formalin, paraformaldehyde, glyoxal per mole of phenols, either alone or in mixtures, such as alkylphenols having _three or more alkyl groups, catechol, resorcinol, pyrogallol, bisphenol A, bisphenol F, and other polyvalent phenols. 0.8 to 3.0 mol of aldehydes, either alone or as a mixture, in the presence of an alkaline catalyst, such as an alkali metal hydroxide, an alkaline earth metal oxide or hydroxide, an amine, or an alkaline catalyst such as ammonia, alone or as a mixture; Preferably, after reacting at 50 to 100°C, the catalyst is neutralized with an inorganic or organic acid such as sulfuric acid or p-toluenesulfonic acid, etc., and then dehydrated and concentrated under reduced pressure. Resol-type phenolic resins with a viscosity of 500 to 200,000 centipoise are particularly preferably used, but inorganic or organic acids such as hydrochloric acid, oxalic acid, p-toluenesulfonic acid, or divalent metal salts such as zinc acetate are used as catalysts. Also used are novolac-type phenolic resins produced, or mixed resins mainly composed of resol-type phenolic resins, including benzyl ether-type phenolic resins produced using divalent metal salts such as lead acetate as catalysts. The blowing agent used in the present invention is not particularly limited to those described below, but includes, for example, halogenated hydrocarbons such as methylene chloride, trichloromonofluoromethane, 1,1,2-trichlorotrifluoromethane, etc. Gases such as carbon dioxide can be generated by mixing fluorine-containing halogenated hydrocarbons such as ethane and 1,2-dichlorotetrafluoroethane, aliphatic hydrocarbons such as butane, pentane, and hexane, and even acids. Chemically reactive foaming agents such as sodium bicarbonate may be used alone or in combination, and the amount thereof is 1 to 50 parts by weight per 100 parts by weight of the phenolic resin calculated as solid resin content. The curing agent used in the present invention is not particularly limited to those described below, but examples include para-toluenesulfonic acid, xylenesulfonic acid, meta-xylenesulfonic acid, benzenesulfonic acid, phenolsulfonic acid, and polymeric acid. In addition to organic sulfonic acids such as sulfonic acid and styrene sulfonic acid, inorganic acids such as phosphoric acid and sulfuric acid may be used singly or as a mixture. ~100 parts by weight. Foam stabilizers used in the present invention are not particularly limited to those described below, but include, for example, polysiloxanes, polyoxyethylene sorbitan fatty acid esters, castor oil ethylene oxide adducts, and alkylphenol ethylene oxide adducts. The compounding amount thereof is 0.3 to 10 parts by weight per 100 parts by weight of the phenolic resin calculated as solid resin content.
Furthermore, commonly used curing accelerators, flame retardants,
Additives such as a neutralizing agent, an organic or inorganic filler, or a coloring agent may also be used as required. Next, in order to obtain the phenolic resin foam of the present invention, a foamable resin composition is prepared by suitably selecting and blending each of the above components and mixing them uniformly, and then injected into a predetermined mold and foamed. Let it harden. For example, if necessary, flame retardants, neutralizers, organic or inorganic fillers, pigments, etc. are blended into a phenolic resin system liquid to which unmodified starch and foam stabilizer have been internally added.
Furthermore, predetermined amounts of blowing agent and curing agent are added sequentially or simultaneously and mixed with stirring, and heated to 30 to 90℃ in advance.
The foam is injected into a predetermined mold at a controlled temperature and then foamed and cured under pressure to obtain the desired foam. Examples of industrial mixing methods include a batch type high-speed stirring method, a continuous high-speed stirring method, a spray mixing method, a floss method, and the like. Examples of the molding method include a method in which the foamable resin composition obtained by the above-mentioned mixing method is flowed onto an endless conveyor, a method in which the foamable resin composition is flowed out in spots and foamed partially, and a method in which the foamable resin composition is foamed under pressure in a mold. There are two methods: a method of making a foam block by inserting the material into a space of a certain size, and a method of filling and foaming the material by press-fitting it into a cavity. Note that the foam obtained by the present invention, for example, the foam obtained using an aqueous phenolsulfonic acid solution as an acidic curing agent, can be heat-treated at an ambient temperature of about 50°C or higher for about 30 minutes or more to change its color tone. It has an extremely advantageous property in terms of quality control of foaming resin compositions, in that it changes color from pink to dark purple. [Effect] Although the effect of the measures taken in the present invention is not clear, it is thought to be as follows. Unmodified starch is decomposed into saccharides by an acidic curing agent, and is thought to have the effect of increasing the surface plasticity (stickiness) of the cell membrane that forms the foam. It is thought that this eliminates fragility or breakage of the membrane due to the fragility, and prevents movement and release of the foaming gas, which has a lower thermal conductivity than air and is contained in the bubble membrane. [Example] Next, the present invention will be specifically explained with reference to Examples and Comparative Examples, but the present invention is not limited in any way by these. In addition, parts and % in examples
represents parts by weight, weight %. Example 1 300 kg of phenol and 346 kg of 47% formalin were charged into a reaction vessel equipped with a stirrer, a reflux tube, and a thermometer. Next, 30 kg of 20% sodium hydroxide aqueous solution was added, and the temperature was raised from room temperature to 90°C in about 60 minutes.
The reaction was continued for 75 minutes at the same temperature. The viscosity of the reactant was 30 cp/50°C. Then, the reaction mixture was cooled to 40°C, and a 10% aqueous sulfuric acid solution was added to adjust the pH to 6.5.
The pressure of the reaction vessel was reduced to 60 mmHg and concentration was performed to obtain 470 kg of resin with a viscosity of 1800 cp at 25°C and a solid resin content of 81% (non-volatile content after drying on a 180°C hot plate for 30 minutes).
Add cornstarch to 100kg of the obtained phenolic resin.
2.43Kg was added and CX-100 (trade name,
Daiichi Kogyo Seiyaku Co., Ltd., castor oil ethylene oxide adduct), ammonium polyphosphate 3Kg as a flame retardant
A mixture of the above is used as a liquid, Freon 113 is used as a foaming agent, and 67% phenolsulfonic acid is used as a hardening agent. used, liquid/
Mix at a ratio of liquid/liquid = 100 parts/25 parts/35 parts,
1800 x 900 with decorative steel plate heated to 70℃ as surface material
A foam with a size of 25 mm was created. The gel time at this time was 120 seconds. After leaving this foam at room temperature for 4 days, the density (JISA9514), flyability (ASTM-421), bond strength with the surface material (measurement method shown below), oxygen index (JIS K7201), and flame conductivity (hot wire method) was measured. The thermal conductivity was also measured after being left for 30 days. Here, the bonding force with the facing material is determined by cutting out a 25 x 150 mm foam with a facing material, making a hole with a diameter of 5 mm at the end of the facing material, hooking a spring gauge there, and pulling it up until the facing material is peeled off from the foam. The value indicated by the spring meter when the force is applied is expressed as the bonding force. As shown in Table 1, the obtained foam has a good appearance, low flyability, strong bonding strength with the facing material, excellent heat insulation performance with little deterioration over time, and is also flame retardant. It was a very good product that did not harm the sex. Comparative Example 1 A foam was created according to Example 1 without adding cornstarch. As shown in Table 1, the obtained foam had a high flyability, a weak bonding force with the face material, and a very large deterioration in heat insulation performance over time.

【table】

〔Effect of the invention〕

The phenolic resin foam according to the present invention greatly improves flyability and adhesion to the surface material, so it improves workability during construction and has excellent thermal conductivity with little decline over time. Because it has excellent heat insulation performance, construction costs can be reduced. Furthermore,
It has the advantage of not compromising its excellent physical properties such as heat resistance, fire resistance, and low smoke emission.

Claims (1)

[Claims] 1 Liquid phenolic resin, foaming agent, acidic curing agent,
A phenolic resin foam obtained by foaming and curing a blended composition containing a foaming agent and unmodified starch as essential components, in which the amount of unmodified starch is based on 100 parts by weight of the phenolic resin converted to solid resin content. ,
A phenolic resin foam having a content of 0.1 to 50 parts by weight.