JP2001302831A - Method for producing phenolic resin foam - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a robust phenolic resin foam little in formaldehyde odor, causing no deformation thereof due to change in temperature and with time. SOLUTION: This method for producing a phenolic resin foam comprises expansion molding of a formula liquid essentially containing a phenolic resin, a foaming agent and a curing agent; more specifically, this method comprises the following practice: a silicone rubber form 3 and a core material 5 are set inside a mold 1 composed of openable two mold members 2a and 2b, and the resulting space 4 is injected with the above formula liquid followed by making an expansion molding and then heat treatments at a temp. of 40-70 deg.C and 100-130 deg.C.

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 used for building materials and industrial materials.
More specifically, the present invention relates to a method for producing a strong phenol resin foam which has little formaldehyde odor and does not undergo deformation due to aging and temperature changes.

[0002]

2. Description of the Related Art Conventionally, synthetic resins are often used as building materials and industrial materials. In the construction field, it is used as an alternative to natural wood for interior materials such as wall materials, partitioning materials, doors, underfloor insulation, ceiling materials, and sliding doors. Attention has been paid to compensate for defects such as swelling and shrinkage due to moisture release.

[0003] In modern buildings, in particular, with the partial revision of the certification for building materials, the point of non-combustibility has been widely taken up, and various measures have been taken to impart fire resistance to synthetic resin products. For example, many products having flame retardancy by adding a flame retardant, an organic or inorganic filler, or compounding a highly fire-resistant skin material with a synthetic resin are commercially available. However, polyurethane foams, polystyrene foams, and the like, which are generally used as synthetic resins, are not satisfactory in terms of nonflammability of the resin foams themselves, and lack fireproofing properties as interior materials.

[0004] Against this background, in recent years, phenolic resin foams have attracted attention for their flame retardancy, which is the least flammable among plastic foams.
It is expected to be used as an interior material because it has soundproofing properties and good chemical resistance and weather resistance. Its flame retardancy is
JISA with phenolic resin foam alone or simple composite
It is possible to obtain the judgment of the second class of the flame retardancy by 1321.

[0005]

However, since the phenolic resin foam generates little self-heating during foaming and curing, external heating is required for production. The reaction proceeds gradually from the surface to the inside by the external heating, so that the reaction is continued inside even after the surface is hardened. For this reason,
Gas components generated inside and air mixed during stirring cannot be released from the surface and remain inside the foam even after molding. When a phenolic resin foam is used at high temperatures, such as in summer, this residual gas, air, and condensed water generated during the reaction expand, causing deformation such as swelling and warping, and moisture evaporating from the surface over time. Shrinkage has been a problem. Such deformation not only impairs the aesthetic appearance of the product, but also renders it unusable, possibly resulting in cracks.

Further, the phenolic resin foam also has a problem that free formaldehyde remains in the foam due to the property that the phenolic resin is a synthetic resin of phenols and formaldehyde. Formaldehyde is a causative substance of sick house syndrome, which has become a social problem, and its countermeasures have been strongly demanded in recent years. Therefore, formaldehyde removal is an essential condition for a comfortable and safe living environment and working environment. To solve the above problem, Japanese Patent Application Laid-Open No. 4-53844 discloses that a phenol resin foam is subjected to a high heat treatment at 130 ° C. or more to remove free formaldehyde. However, the above-mentioned invention has a fatal defect that swelling and warpage occur during high heat treatment for the reasons described above.

The present invention has been made to solve the above problems, and provides a method for producing a strong phenolic resin foam which has little formaldehyde odor and has no deformation such as swelling or warping or shrinkage due to aging even at high temperatures. The purpose is to do.

[0008]

That is, according to the first aspect of the present invention, there is provided a method for producing a phenolic resin foam obtained by foaming and curing a liquid mixture containing at least a phenolic resin, a foaming agent and a curing agent. A method for producing a phenolic foam, wherein the liquid is subjected to at least two-stage heat treatment after foam molding, and the first-stage heat treatment is lower in temperature than the second-stage heat treatment. In the first stage heat treatment,
Preliminary hardening is performed to prevent deformation such as swelling and warping that occurs during the second-stage heat treatment, and the second-stage heat treatment is performed to prevent deformation such as swelling, warping, and shrinkage that occur when the product is used at high temperatures. Perform full-scale curing. Therefore, the first-stage heat treatment needs to be lower in temperature than the second-stage heat treatment.

According to a second aspect of the present invention, there is provided a method for producing a phenolic resin foam obtained by foaming and curing a compounded liquid containing at least a phenolic resin, a foaming agent, a curing agent, and aluminum hydroxide. 40 to 200 parts by weight are added to 100 parts by weight,
The foamed mixture is subjected to at least two-stage heat treatment after foam molding, and the first-stage heat treatment is lower in temperature than the second-stage heat treatment, and the density of the phenol resin foam after the heat treatment is reduced to 0.5%.
By adjusting to 0.7 g / cm ³ , JISA 13
It is possible to obtain a first-class determination of flame retardancy in a surface test of 21 building material combustion evaluations.

According to the invention described in claim 3 of the present application, claim 1
Or the method for producing a phenolic resin foam according to item 2, wherein the first-stage heat treatment is a heat treatment of less than 90 ° C. and the second-stage heat treatment is a heat treatment of 90 ° C. or more. By performing a two-stage heat treatment at 90 ° C., it is possible to prevent deformation due to steam, remove formaldehyde, and complete the condensation reaction.

According to a fourth aspect of the present invention, in the method for producing a phenolic resin foam according to the first, second, or third aspect, the first-stage heat treatment temperature is set at 40 to 70 ° C. No deformation occurs during the heat treatment, and preliminary curing is sufficiently performed.

[0012] According to the fifth aspect of the present invention, the first, second, and third aspects are provided.
In the method for producing a phenolic resin foam according to item 3 or 4, by setting the second heat treatment temperature to 100 to 130 ° C., moisture and free formaldehyde can be sufficiently removed, and the device can withstand long-term use. You can get strong power.

[0013]

DETAILED DESCRIPTION OF THE INVENTION In the present invention, any of the phenolic resin foams that can be used can be used. A phenol resin is a synthetic resin obtained by a reaction between phenols and aldehydes. Examples of phenols include phenol, o-cresol, m-cresol, p-cresol, p-tert-butylphenol, and p-tert.
Octylphenol, p-nonylphenol, 2,4
-Xylenol, 2,5-xylenol, 2,6-xylenol, 3,4-xylenol, 3,5-xylenol, resorcinol, bisphenol-A, catechol, hydroquinone and the like. Phenolic resins are roughly classified into resol-type phenolic resins and novolak-type phenolic resins according to the reaction conditions such as the ratio of phenols to formaldehyde and the catalyst. In the present invention, resol-type phenolic resins are used. Also, a benzylic ether type phenol resin which is a special resol can be used.

As the curing agent, an acidic curing agent is used. Commonly used as acidic curing agents include:
Examples thereof include organic acids such as p-toluenesulfonic acid, phenolsulfonic acid, xylenesulfonic acid, and benzenesulfonic acid, and inorganic acids such as sulfuric acid, hydrochloric acid, and phosphoric acid. These acid curing agents can be used alone or in combination of two or more.

As the foaming agent, fluorocarbons such as fluorotrichloromethane and trifluorotrichloroethane were generally used. However, alternatives have recently been studied from the viewpoint of environmental problems such as destruction of the ozone layer. In the present invention, known ones can be used, but it is preferable to use one in consideration of safety and environmental aspects. Specifically, volatile hydrocarbons such as butane, pentane, hexane, gasoline, and naphtha; ketones such as acetone and methyl ethyl ketone; alcohols such as methyl alcohol and ethyl alcohol; and halogenated hydrocarbons such as methylene chloride. Is mentioned. These may be used alone or in combination of two or more.

[0016] Inorganic fillers can be added. Specifically, clay, calcium carbonate, ammonium borate, potassium borate, zinc powder, zinc phosphate, aluminum phosphate,
Ferrite, magnetite, silicon dioxide, aluminum hydroxide and the like can be mentioned, and these can be used alone or as a mixture of two or more. Among them, aluminum hydroxide is preferable. Aluminum hydroxide, besides the advantage of low cost, is less susceptible to burning itself and 240 to 5
Since it undergoes a dehydration endothermic reaction at 50 ° C., it exhibits an excellent flame retardant effect such as suppression of resin ignition or continuous inhibition of combustion. Further, an organic filler such as melamine, dicyandiamide, or gelled powdery synthetic resin may be added.

Further, as a generally used flame retardant,
An organic phosphorus compound may be added. Specifically, trimethyl phosphate, triethyl phosphate, tributyl phosphate, trischloroethyl phosphate, trischloropropyl phosphate, trisdichloropropyl phosphate, tris resyl phosphate, trisixylenyl phosphate, cresyl There are diphenyl phosphate, xylenyl diphenyl phosphate and the like.

A fibrous base material may be added. This functions as a dimensional stabilizer, specifically, glass fiber, carbon fiber, aramid fiber, polyimide fiber, novoloid fiber,
Asbestos, ceramic fibers, metal fibers and the like can be used.

A foam stabilizer can be added. In the present invention, known compounds can be used, and specific examples thereof include nonionic surfactants and silicone surfactants.

[0020] A formaldehyde scavenger may be added. The effect of removing formaldehyde that cannot be completely removed by the heat treatment of the present invention can be expected. The use is not particularly limited, but examples thereof include physical adsorption with silica, activated carbon, and the like, and chemical adsorption with a hydrazide compound, a dihydrazide compound, an azole compound, an azine compound, and the like.

The addition amount of the above-mentioned compounding agent is
0.5 to 40 parts by weight of a foaming agent, 1 to 50 parts by weight of a curing agent, 0.1 to 10 parts by weight of a foam stabilizer, and 10 to 200 parts by weight of an inorganic filler, based on 0 part by weight. .

The above-mentioned composition is mixed and stirred by a known method to carry out foam molding. Known techniques such as slab foaming, mold foaming, panel foaming, laminate board foaming, and spray foaming can be used as the foam molding method.
When a mold is used, its shape is not particularly limited, but a shape devised to prevent gas or air accumulation generated during foam molding is preferable. The foam molding conditions are preferably 30 to 80 ° C. for 2 to 60 minutes.

An example of the foam molding method will be described with reference to the accompanying drawings. However, the following is one embodiment, and the present invention is not limited to this. FIG. 1 is a cross-sectional view of a mold 1. The mold 1 includes two mold members 2a and 2b that can be opened and closed, and a space 4, and has an inlet (not shown) for a phenolic resin compounding liquid. I have. A silicone rubber mold 3 can be installed in the space portion 4, and the silicone rubber mold 3 is in a cylindrical state having a handle-shaped cut-out portion 6 divided into two along a dividing line in a longitudinal direction in order to take out a molded product. . After the core material 5 is installed at the center of the mold 1, a phenol resin compounding liquid is injected into the space 4 and foamed. The silicone rubber has cuts (not shown) penetrating in the thickness direction in order to degas gas and air generated at the time of molding and foaming.

The core material to be used is not limited to a material having straightness in the longitudinal direction, and may have a curve or a single bend. The absence of the above-described grooves and steps is preferable for the purpose of reducing the contraction stress in the longitudinal direction of the foam. Usually, when forming into a plate shape, a steel plate, an aluminum plate, a gypsum board, an asbestos slate plate, a calcium silicate plate, a wooden plate, a plywood, a particle board, an MDF plate, or the like is used. When forming into a cylindrical or prismatic shape, it is possible to use rod-like or prismatic iron materials, reinforced concrete materials, aluminum materials, wood, laminated materials, etc., or steel pipes, aluminum pipes, paper pipes, etc. on round pipes or square pipes. it can.

In order to alleviate the shrinkage stress during foam molding and prevent internal cracks, the surface of the core material may be surrounded by a buffer sheet. As the buffer sheet, a highly expanded polyolefin sheet, a foamed or non-foamed rubber sheet, or the like is used, and its thickness is preferably about 1 to 2 mm.

After foam molding as described above, a heat treatment characteristic of the present invention is performed. First, a first-stage heat treatment is performed. This heat treatment is preferably below 90 ° C. 90 ° C
If the temperature exceeds the limit, water vapor is generated, and internal cracks may be generated during the first stage heat treatment. More preferably 40 to 7
When the temperature is 0 ° C and lower than 40 ° C, the curing is insufficient. The processing time is preferably at least 3 hours, more preferably at least 5 hours. In this heat treatment, preliminary curing is performed to a strength that can withstand the expansion of the gas component and the water vapor pressure generated in the second heat treatment. If this heat treatment is not performed, swelling and warpage occur during the second heat treatment.

Next, a second stage heat treatment is performed. The heat treatment temperature is preferably 90 ° C. or higher. More preferably, 1
It is 00 to 130 ° C., and it is not preferable that the temperature is 150 ° C. or more in consideration of heat resistance. The processing time is preferably at least 3 hours, more preferably at least 5 hours. This high heat treatment completes the curing reaction, completes the shrinkage, and removes free formaldehyde. By this high heat treatment, it is possible to provide a foam which has high strength even after production and which can withstand use even at high heat.

The heat treatment in the first stage and the heat treatment in the second stage may be continuous or discontinuous. Specifically, the term “discontinuous” means that after the first-stage heat treatment, the substrate is left at room temperature, and then the second-stage heat treatment is performed. When the heat treatment is continuous, the transition from the first heat treatment to the second heat treatment may be performed from the first heat treatment to the second heat treatment in a variable temperature heat treatment apparatus. The heat treatment in the second step and the heat treatment in the second step may be performed by different heat treatment apparatuses. Further, the heat treatment is not limited to two stages, but three or more stages of heat treatment are also possible. In the case of a foam molding method using a mold, it is desirable to remove the phenolic resin foam from the mold and perform the heat treatment.

Further, the phenolic resin foam according to the present invention
Table of flammability evaluation of building materials according to JIS A 1321
In order to obtain the first grade of flame retardance by the surface test,
To give the density and flame retardancy of phenolic resin foam
It is preferable to control the selection of the agents and the mixing ratio. Pheno
The density of the resin foam depends on the amount of the compound added, the mixing ratio, and the foaming.
Volume, temperature, mold shape, etc.
Adjust appropriately according to the need and situation. In the above determination,
As a result of intensive studies conducted by the present inventors, it was found that phenol resin 10
Aluminum hydroxide as inorganic filler for 0 parts by weight
Pheno after heat treatment.
0.5-0.7 g / cm ^ThreeTones
It is found that it satisfies the flame retardant first class criteria
Was. In addition, other than aluminum hydroxide,
It is of course possible to add machine filler.

The phenolic resin foam according to the present invention can be provided with flame retardancy and design by coating with a decorative sheet or the like or providing a surface finishing layer by painting or the like according to the purpose of use. It is. Further, the formaldehyde scavenger may be added to a paint or the like.

[0031]

Next, the present invention will be described in more detail with reference to specific examples. Examples 1-4, Comparative Examples 1-4 In 100 parts by weight of a liquid resol type phenol resin solution (manufactured by Dainippon Ink and Chemicals, Inc.), 1 part by weight of silicone-modified oil as a foam stabilizer (manufactured by Dow Corning Toray Silicone Co., Ltd.) : SH-193), 1.5 parts by weight of pentane and 1.5 parts by weight of hexane were added and mixed as a foaming agent, and then 50 parts by weight of aluminum hydroxide (manufactured by Showa Denko KK: Heidilite) as an inorganic filler. As a dimension stabilizer, 20 parts by weight of glass fiber (Mild Fiber manufactured by Central Glass Co., Ltd.) was added and mixed with stirring to prepare a phenol resin compounding liquid.

A silicone rubber mold made by drawing a drawn log of a natural cedar having a tip diameter of 120 mm and a length of 3 m into a resin mold reinforced with a two-part iron frame is cut open in the longitudinal direction. Set the diameter 90 as the core material in the center
A laminated wood having a length of 3.1 m and a length of 3.1 mm was installed and the mold was closed.

After the mold was heated to 55 ° C., the upper casting port was opened at an angle of 45 ° C., and 15 parts by weight of a 63% phenolsulfonic acid aqueous solution (Daiichi Kogyo Co., Ltd.) (Resinol PS-63, manufactured by Pharmaceutical Co., Ltd.) was added thereto, and the mixed solution that was vigorously stirred was immediately poured, and allowed to stand for 20 minutes to perform foaming and curing.

Thereafter, the molded body was released from the mold and heat-treated in an oven under the conditions shown in Table 1, and the occurrence of blistering during the second stage heat treatment was examined. After sufficiently cooling the phenolic resin foam obtained by the heat treatment, the phenol resin foam was used at a high temperature of 100 ° C. to examine deformation such as swelling, shrinkage, and warpage.

[0035]

[Table 1]

As a result, in the example, no swelling occurred during the heat treatment in the second stage, there was almost no deformation even when used as a product at a high temperature, and the odor of formaldehyde was slight. On the other hand, in Comparative Examples 1, 2, and 3, swelling was not observed immediately after molding, but significant deformation was observed when used as a product at a high temperature. In Comparative Example 4, swelling occurred during the heat treatment at 100 ° C., and the molded product could not be used as a product.

Examples 5 and 6 and Reference Examples 1 to 3 Next, of the foaming conditions of the above-mentioned phenolic resin-compounded liquid, the amount of the curing agent added and the foaming temperature were changed to change the density of the foam. A resin foam was produced. 2
The heat treatment conditions in the first step are 5 hours at 60 ° C. as the first heat treatment and 5 hours at 100 ° C. as the second heat treatment. Further, under the conditions of Table 2, the amount of aluminum hydroxide added was varied among the above formulations, and the obtained phenolic resin foam was subjected to a surface test of flammability evaluation of building materials according to JIS.
A 1321. The results are also shown in Table 2. The shape of the sample used for the surface test is JI
It is based on SA 1321.

[0038]

[Table 2]

From the above results, it was possible to judge the first grade of the flame retardant in the examples, while the reference example was the second grade of the flame retardant.

[0040]

As described above, according to the invention of the present application, it is possible to provide a strong phenol resin foam which has little formaldehyde odor and does not undergo deformation due to aging and temperature changes. Further, the non-combustible property of the phenolic resin foam is enhanced by the production method according to the second aspect of the present invention,
It was possible to determine the first grade of flame retardancy in the surface test according to JIS A 1321.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a mold during foam molding in a method for producing a phenolic resin foam according to the present invention.

[Explanation of symbols]

 1 mold 3 silicone rubber mold 4 space 5 core material

 ──────────────────────────────────────────────────続 き Continued on front page F term (reference) 4F074 AA59 AC20 AD15 BA37 BA38 BA39 BA40 BA46 BA53 BA73 BA74 BB01 BC05 CA23 CA30 CC04Y CC04Z CC06Y CC22X CC32Y CC32Z DA02 DA32 4J002 CC031 DD017 DE148 DG047 DH027 EA016 EB066 EC36 EB066 EC36 GL00

Claims (5)

[Claims] 1. A method for producing a phenolic resin foam obtained by foaming and curing a blended liquid containing at least a phenolic resin, a foaming agent, and a curing agent, wherein the blended liquid is subjected to at least two stages of heat treatment after foam molding. A method for producing a phenolic resin foam, wherein the heat treatment is lower in temperature than the heat treatment in the second step. 2. A method for producing a phenolic resin foam obtained by foaming and curing a compounded liquid containing at least a phenolic resin, a foaming agent, a curing agent, and aluminum hydroxide.
The mixture is subjected to at least two-stage heat treatment after foam molding, and the first-stage heat treatment is lower in temperature than the second-stage heat treatment, and the phenolic resin foam after the two-stage heat treatment is added. Body density 0.5-0.7g /
cm ³ , a method for producing a phenolic resin foam. 3. The method for producing a phenolic resin foam according to claim 1, wherein the first-stage heat treatment is a heat treatment at less than 90 ° C. and the second-stage heat treatment is a heat treatment at 90 ° C. or more. 4. The first stage heat treatment is performed at 40 to 70 ° C.
The method for producing a phenolic resin foam according to claim 1, 2, or 3, which is a heat treatment. 5. The heat treatment of the second stage is performed at 100 to 130.
5. The method for producing a phenolic resin foam according to claim 1, wherein the heat treatment is carried out at a temperature of ° C.