JPH0665413A - Production of phenol resin foamed product - Google Patents

Abstract

PURPOSE:To provide the improved method for producing the phenol resin foamed product having uniform foams and high heat resistance without decomposing the ozone layer in the atmosphere by employing a new foaming agent, in the method for producing the phenol resin foamed product having a light weight, high heat resistance and high flame retardancy. CONSTITUTION:This method for producing the phenol resin foamed product by mixing a liquid phenolic resin with a foaming agent and an acidic curing agent to foam and cure the liquid phenol resin is characterized by employing a mixture of dichloropentafluoropropane with dichlorofluoroethane in a weight ratio of 80:20 to 20:80.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a phenol resin foam which is lightweight and has high heat insulation and high heat resistance,
More specifically, it relates to an improved production method for producing a phenol resin foam having uniform cells and high heat insulation by using a novel foaming agent.

[0002]

2. Description of the Related Art Generally, when a phenol resin foam is obtained from a liquid phenol resin, a resol type or benzylic ether type phenol resin is used as the phenol resin. As the foaming agent, trichlorotrifluoroethane (CFC-113), trichloromonofluoromethane (CFC-11), halogenated hydrocarbons such as dichloromethane and hydrocarbons such as pentane and hexane are generally used. As additives, surfactants as a foam stabilizer, flame retardants, neutralizing agents, etc. are used. As the curing agent, an inorganic acid, an organic acid, a solution thereof or the like is used. A method is known in which these raw materials are uniformly mixed and then sprayed or poured into a mold or the like to foam and cure to obtain a phenol resin foam. Incidentally, as a conventional technique, Japanese Patent Application Laid-Open No. 3-2 of the present inventor is used.
There is 55142.

[0003]

When a hydrocarbon is used as a foaming agent, these hydrocarbons and their derivatives have a strong flammability, and in the manufacturing processes such as compounding, foaming, curing and curing, the flammability causes a fire. Since there is a high risk of occurrence of equipment and it is necessary to make equipment that performs these processes explosion proof, equipment investment will be extremely large. In addition, the work in these steps requires extreme caution to prevent fire. In addition, the flame retardancy inherent in the phenol resin foam is impaired due to the flammable hydrocarbon or its derivative gas contained in the bubbles of the obtained foam. Further, since the thermal conductivity of the gas of the hydrocarbon or its derivative contained in the bubbles is higher than that of the gas of the halogenated hydrocarbon or its derivative, a phenol resin foam using the halogenated hydrocarbon or its derivative as a foaming agent. The thermal conductivity is higher than that of and the performance as a heat insulating material is impaired. Trichlorotrifluoroethane (C
FC-113), trichloromonofluoromethane (CF
C-11), dichlorotrifluoroethane (HCFC-
123), dichlorofluoroethane (HCFC-141
b), when using a halogenated hydrocarbon such as dichloromethane or pentafluoropropyl alcohol, or a derivative thereof, these foaming agents have no flash point, the manufacturing process is safe, and the thermal conductivity as a gas is small, so a gas is used. When enclosed in a foam, the resulting foam also has excellent heat insulation. However, as a foaming agent, CFC-113, CFC
When -11 or the like is used, CFC-113, CFC-11
Since they are extremely stable compounds, they reach the stratosphere without being decomposed in the troposphere, are decomposed by ultraviolet rays in the stratosphere and release chlorine atoms, and these chlorine atoms decompose ozone in the stratosphere and cause destruction of the ozone layer. As a cause of environmental destruction at the global level, it is currently becoming a global problem, and it is specified as a specified CFC in the "Montreal Protocol", and the regulation of manufacturing and usage has already been advanced worldwide. Therefore, this CFC-113, CFC-1
It is necessary to reduce the use of 1 etc. in accordance with regulations and replace it with another foaming agent etc., and abolish it. HCFC- as a foaming agent
When 123, HCFC-141b, dichloromethane or the like is used, these foaming agents have hydrogen atoms in the molecule and are easily decomposed in the troposphere, so that the ability to decompose ozone in the stratosphere is small and the adverse effect on the environment is also small. However, as a foaming agent for producing a phenolic resin foam, it is difficult to obtain a foam having uniform and fine cells only by these, and CFC-1
HCFC used in combination with 13, pentane, hexane, etc.
It is difficult to obtain a foam having uniform and fine cells and excellent quality unless the amount of -123, HCFC-141b, dichloromethane, etc. used is 50% by weight or less of the total amount of the blowing agent used. This is HCFC-123, HCFC-14
It is considered that the solubility of 1b or the like in the liquid phenol resin is too good and the boiling point is too low. Therefore, it is necessary to use a combined-use foaming agent as described above, and it is impossible to avoid the above-mentioned problems caused by using CFC-113, pentane, hexane and the like.

[0004]

Means for Solving the Problems As a result of intensive research for solving the above problems, the present invention has been achieved. In other words, in the production of phenolic resin foams, the danger of environmental damage and fire is greatly increased by not using the conventional halogenated hydrocarbons with a high ozone depletion potential (ODP) or low boiling point hydrocarbons with a high flammability. The present invention has led to the establishment of a method for producing a phenolic resin foam having improved heat resistance and excellent heat insulation performance. The present invention relates to a method for producing a phenol resin foam from a liquid phenol resin, a foaming agent, other additives and a curing agent, which is a mixture of dichloropentafluoropropane and dichlorofluoroethane as the foaming agent. The mixing weight ratio of 80: 2
The use of a blowing agent which does not destroy the ozone layer in the atmosphere has been successful by using a mixture in the range 0-20: 80.

The liquid phenol resin used in the present invention is not particularly limited, and the presence of a resole type phenol resin obtained by reacting phenols and aldehydes in the presence of an alkaline catalyst, a neutral metal salt catalyst, etc. Examples thereof include a benzylic ether type phenol resin obtained by reacting under the following conditions. The mixing ratio of the mixture of dichloropentafluoropropane and dichlorofluoroethane used as a foaming agent in the method for producing a phenol resin foam of the present invention is 80:20 to 2 by weight.
The mixing ratio in the range of 0:80 is good, and more preferably 70 :.
30-40: 60. When this mixing ratio is greater than 80:20, the dispersibility of the liquid phenol resin and the foaming agent is not sufficient, a uniform foam cannot be obtained, and the heat insulating property deteriorates. On the other hand, when the mixing ratio is less than 20:80, the solubility of the foaming agent in the liquid phenol resin becomes large, the bubbles of the foam become large and the texture becomes rough, and the physical properties such as strength and heat insulating property deteriorate. As dichloropentafluoropropane as a foaming agent, 1,1-dichloro-2,2,3,3-
Pentafluoropropane (HCFC-225ca),
All isomers such as 1,3-dichloro-1,1,2,2,3-pentafluoropropane (HCFC-225cb) can be used, and one of these isomers can be used alone. It is also possible to use mixtures of one or more isomers in any proportion. As dichlorofluoroethane, 1,1-dichloro-1-fluoroethane (HCFC-
141b) or the like can be used. The total amount of the foaming agent used is not particularly limited, but is 1 to 60 parts by weight, preferably 4 parts by weight with respect to 100 parts by weight of the liquid phenol resin.
It is recommended that the amount be ˜40 parts by weight. As the additives, known surfactants, flame retardants, neutralizing agents, fillers and other additives can be added. As a curing agent, phosphoric acid, phosphorous acid, hypophosphorous acid, pyrophosphoric acid, tripolyphosphoric acid, polyphosphoric acid, hydrochloric acid, inorganic acids such as sulfuric acid, phenolsulfonic acid,
Organic acids such as aryl sulfonic acids such as toluene sulfonic acid, xylene sulfonic acid and benzene sulfonic acid, and alkyl sulfonic acids such as methane sulfonic acid are used, but not limited thereto. Further, these curing agents can be used alone or in combination of two or more kinds, and can be used as an aqueous solution, another solution, or a non-solution. The amount of the curing agent used is not particularly limited, but it is preferably 1 to 60 parts by weight, and more preferably 5 to 30 parts by weight with respect to 100 parts by weight of the liquid phenol resin. In the present invention, the phenol resin foam is obtained by uniformly mixing the above-mentioned raw materials, and then spraying or pouring the mixture into a mold or the like and foam-curing. The foaming and hardening step can be performed at room temperature or under a heated atmosphere. When these materials are mixed in a batch, a stirrer such as a disperser is used, and when continuously mixed, a known multi-component mixing and foaming machine is used. Further, the mixed raw materials may be foamed and cured in a mold, for example, and the product may be released from the mold as it is, or further processed into a required shape to obtain a product. The mixed raw materials are, for example, kraft paper, aluminum hydroxide paper, asbestos paper, asphalt paper, calcium carbonate paper, aluminum kraft paper, iron foil, stainless steel foil, soft film such as plastic film or sheet, steel plate, aluminum plate. ， Injected between hard surface materials such as stainless steel plates, boards, panels,
It can also be made into a product in the form of a siding material or the like. Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples.

[0006]

【Example】

Example 100 parts by weight of phenol, 173 parts by weight of 37% formaldehyde aqueous solution and 1 part by weight of sodium hydroxide were placed in a reaction vessel and reacted at 90 ° C. for 3 hours, followed by dehydration under reduced pressure to obtain a resol type liquid phenol resin. . In 100 parts by weight of this resol-type phenol resin, 2 parts by weight of a silicon-based surfactant L-5420 (manufactured by Nippon Unicar) as a foam stabilizer and dichloropentafluoropropane and dichlorofluoroethane as blowing agents are shown in Table 1. 10 parts by weight of the foaming agent mixed in a ratio were mixed in advance to prepare a premix component, and 15 parts by weight of a 65% phenolsulfonic acid aqueous solution as a curing agent was added thereto, and the mixture was stirred with a lab mixer for 10 seconds to give 300 × 300 × Pour into an open mold of 300 mm and heat in an atmosphere of 70 ° C for 10 minutes,
A phenol resin foam was obtained. Table 1 shows the physical properties of the obtained foam.

[0007]

[Table 1]

Comparative Example Similar to Example 1 except that dichloropentafluoropropane alone, dichlorofluoroethane alone, or dichloropentafluoropropane and dichlorofluoroethane were used as the foaming agent in various ratios shown in Table 1. To obtain a phenol resin foam. The results are shown in Table 1 as Comparative Examples 1 to 4. The state of bubbles was visually observed for this phenol resin foam, and ASTM D1
The density was measured by the method specified in 622, the thermal conductivity was measured by the method specified by JISA1412, the compressive strength was measured by the method specified by ASTM D1621, and the closed cell ratio was measured by the method specified in ASTM D2856.

[0009]

The dichloropentafluoropropane and dichlorofluoroethane used as the blowing agent in the present invention have hydrogen atoms in the molecule and are easily decomposed in the troposphere.
It is hard to reach the stratosphere, and the ability to decompose ozone in the stratosphere by decomposing chlorine atoms by releasing ultraviolet rays in the stratosphere to destroy ozone in the stratosphere is small and the problem of environmental destruction is small. Also, since it has no flash point, there is no risk of fire in the manufacturing process, and there is no need to make the manufacturing equipment explosion-proof, so the equipment cost is very low. In addition, by using a mixture of dichloropentafluoropropane and dichlorofluoroethane, the disadvantages of dispersibility in phenol resin and solubility are compensated for each other, and the dispersibility and dissolution in phenol resin are compensated for each other. It is believed that the foaming agent system has improved properties, and that a foam having uniform and fine cells and excellent physical properties can be obtained. In addition, since the thermal conductivity of dichloropentafluoropropane and dichlorofluoroethane in the gaseous state is small, the resulting foam containing dichloropentafluoropropane and dichlorofluoroethane has excellent heat insulating properties. Therefore, by using a mixture of dichloropentafluoropropane and dichlorofluoroethane as a blowing agent, it is possible to significantly improve the quality of the prior art in the above many qualities.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Chiaki Tsukamoto 1176, Uchigaike, 1-6, Inami-cho, Kako-gun, Hyogo Prefecture Toyo Tire & Rubber Co., Ltd. Hyogo Plant Hyogo Factory

Claims (1)

[Claims] 1. A method for producing a phenolic resin foam, which comprises foaming and curing a liquid phenolic resin, a foaming agent and an acidic curing agent by mixing, and a mixture of dichloropentafluoropropane and dichlorofluoroethane as the foaming agent, A method for producing a phenol resin foam, which comprises using a mixture having a mixing weight ratio of the dichloropentafluoropropane and dichlorofluoroethane in the range of 80:20 to 20:80.