JP2002003633A - Method for manufacturing phenolic resin foam - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a phenolic resin foam having a good processability, in which formation of a poor curing part is prevented. SOLUTION: A resol-type phenolic resin solution is added with an alkylammonium salt of polyester and a blowing agent obtained by mixing alcohols having a boiling point of 100 deg. or below and a hydrocarbon, and then it is cured and expanded by further adding an inorganic powder filler and acid curing agent.

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 phenolic resin foam having good processability and preventing occurrence of a poorly cured portion.

[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. 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 itself, and do not have disaster prevention properties as interior materials. Against this background, in recent years, the high flame retardancy of phenolic resin foam has attracted attention, and it has excellent heat resistance, soundproofing, chemical resistance, and good weather resistance. Expected.

[0004]

Further, in recent years, there has been a demand for higher functionality of resin products, and fillers have been added to impart various properties to phenol resin foams. Fillers are roughly classified into organic fillers and inorganic fillers.
Principal inorganic fillers include metal hydrates that function as flame retardants and glass fibers that function as dimensional stabilizers. However, when a powdery inorganic filler such as the above-mentioned inorganic filler is used, there is a problem that the viscosity of the liquid mixture becomes high due to low affinity with the phenol resin.

[0005] As described above, when the viscosity of the blended liquid increases, there is a problem in that the processability and workability are poor, and the dispersion of the blending agent is caused, thereby causing poor curing and poor foaming of the foamed molded article. Further, there is also a problem that the foamed gas bubbles and air bubbles mixed during the stirring and mixing are difficult to escape due to the high viscosity of the material. An object of the present invention is to improve the above-mentioned problems, and an object of the present invention is to provide a method for producing a phenol resin foam which has good workability and prevents occurrence of a poorly cured portion.

[0006]

That is, according to the first aspect of the present invention, there is provided a phenolic resin foam obtained by foaming and curing a liquid mixture containing at least a phenolic resin, a foaming agent, a curing agent, and a powdered inorganic filler. In the above method, an alkylolamine salt of a block copolymer having an acid group is blended with the mixture.

According to the invention described in claim 2 of the present application, claim 1
In the above described method for producing a phenolic resin foam, the alkylolamine salt of an acid group-containing block copolymer is an alkylol ammonium salt of an acid group-containing block copolymer.

According to the invention described in claim 3 of the present application, claim 1
Or in the method for producing a phenolic resin foam according to item 2, wherein at least one of the acid groups is a carboxyl group.

In the invention according to claim 4 of the present application, in the method for producing a phenolic resin foam according to claim 1, 2, or 3, the block copolymer having an acid group has at least an ester bond in its structure.

[0010]

DETAILED DESCRIPTION OF THE INVENTION In the present invention, any of the phenolic resin foams that can be used can be used. The resol type phenol resin, which is the main material, is a synthetic resin obtained by a reaction between phenols and formaldehyde. Phenols include phenol, o-cresol, m
-Cresol, p-cresol, p-tert-butylphenol, 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 can be mentioned.

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.

In the present invention, known foaming agents can be used, but it is preferable to use those in consideration of safety and environment. 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. Can be used.
These may be used alone or in combination of two or more.

However, considering workability and foamability,
As the blowing agent, it is desirable to use alcohols and hydrocarbons in combination. In order to obtain sufficient foaming, the foaming agent must have a boiling point of 100 ° C. or less. Specific examples include alcohols such as methanol, ethanol,
Examples of the hydrocarbon include butane, pentane, and hexane. However, the use of alcohols and hydrocarbons is not limited to one kind, and two or more kinds can be used. For example, a mixture of pentane and hexane in methanol can be used. Further, as the combination ratio of the above foaming agent,
The weight ratio is preferably in the range of 9: 1 to 1: 9, and particularly preferably in the range of 7: 3 to 3: 7.

The powdery inorganic filler refers to an inorganic filler having a particle size of 200 μm or less when the shape is particulate and a fiber length of 300 μm or less when the shape is fibrous. The effect of adding the alkylolamine salt of the block copolymer having an acid group to the inorganic filler having the above particle diameter or fiber length cannot be expected. Although the inorganic filler refers to a known material, concrete examples include clay, calcium carbonate, ammonium borate, potassium borate,
Examples include zinc powder, zinc phosphate, aluminum phosphate, ferrite, magnetite, silicon dioxide, metal hydrate, inorganic fibers such as metal fibers and glass fibers, and inorganic pigments. One or more of these powdery inorganic fillers can be used. The amount of the powdery inorganic filler added is 5 to 2 parts per 100 parts by weight of the phenol resin.
It is preferable to add 50 parts by weight, more preferably 40 to 150 parts by weight.

When the above-mentioned powdery inorganic filler is added to the blending liquid, it is preferable to blend an alkylolamine salt of a block copolymer having an acid group in order to reduce the viscosity. The salt having the above structure has both a portion having an affinity for the resin and a portion adsorbed on the particles in the molecular structure.
More specifically, in a phenolic resin-containing liquid containing a powdered inorganic filler, the polymer portion interacts with the phenolic resin as a soft segment to increase compatibility, and the acid group and functional groups such as alkylolamine are added. It has the effect of adsorbing on the powdered inorganic filler, lowering the attractive force between the particles, and lowering the viscosity. To illustrate the above structure more specifically, the alkylolamine salt of an acid group-containing block copolymer is an alkylol ammonium salt of an acid group-containing block copolymer. Further, it is a block copolymer in which at least one of the acid groups is a carboxyl group and / or has at least an ester bond in its structure.

The amount of the salt having the above structure is preferably 0.2 to 1.5 parts by weight based on 100 parts by weight of the phenol resin. As for the timing of addition, it is desirable to add the salt having the above structure before adding the powdered inorganic filler to the phenol resin solution. The salt having the above structure may be used as a mixture with a suitable solvent.

Incidentally, an inorganic filler which is not in a powder form can of course be added. Further, an organic filler may be added in addition to the inorganic filler. For example, melamine, dicyandiamide, powdered synthetic resin gel, organophosphorus compound,
And organic fibers, such as carbon fiber, aramid fiber, polyimide fiber, novoloid fiber, asbestos, and ceramic fiber, are mentioned.

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.

A formaldehyde scavenger may be added. An effect of removing formaldehyde that cannot be completely removed by heat treatment can be expected. Although there is no particular limitation on the use, for example, physical adsorption by silica or activated carbon, hydrazide compound, dihydrazide compound, azole compound,
One example is chemical adsorption with an azine compound or the like.

[0020] The amount of the above compounding agent is phenol resin 1
The foaming agent is preferably 0.5 to 40 parts by weight, the curing agent is preferably 1 to 50 parts by weight, and the foam stabilizer is preferably 0.1 to 10 parts by weight based on 00 parts 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.

When a core material is used, the core material is not limited to one having straightness in the longitudinal direction, but may have a curve or a single bend. It is preferable that there are no two or more grooves or steps in order to reduce the contraction stress in the longitudinal direction of the foam.
Usually, when forming into a plate shape, steel plate, aluminum plate, gypsum board, asbestos slate plate, calcium silicate plate, wood plate,
Plywood, particle board, MDF board or the like is used. When forming into a cylindrical or prismatic shape, it is possible to use rod-like or prismatic iron, reinforced concrete, aluminum, wood, laminated wood, or steel pipe, aluminum pipe, paper pipe, etc. on a round pipe or square pipe. 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 the foam molding as described above, it is preferable, but not essential, to perform the following two-stage heat treatment. First, the first-stage heat treatment is preferably a heat treatment at less than 90 ° C. If the temperature exceeds 90 ° C., water vapor is generated, and internal cracks may occur during the first heat treatment. More preferably, it is 40 to 70 ° C, and if it is lower than 40 ° C, 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.

The phenolic resin foam according to the present invention alone can be used to obtain the first class of flame retardancy by a surface test of flammability evaluation of building materials according to JIS A 1321 in order to determine the density of the phenolic resin foam after heat treatment. It is preferable to select a compounding agent that imparts flame retardancy and adjust the compounding ratio. Since the density of the phenolic resin foam is affected by the amount of the compound added, the mixing ratio, the foaming amount, the temperature, the shape of the mold, and the like, the density is appropriately adjusted according to needs and circumstances.

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

[0029]

Next, the present invention will be described in more detail with reference to specific examples. Examples 1 and 2, Comparative Example 1 100 parts by weight of a liquid resol type phenol resin solution (manufactured by Dainippon Ink and Chemicals, Inc.) and 1 part by weight of silicone-modified oil as a foam stabilizer (manufactured by Dow Corning Toray Silicone Co., Ltd .: SH) After adding and mixing 1.5 parts by weight of pentane and 1.5 parts by weight of methanol as a foaming agent, 50 parts by weight of aluminum hydroxide as a powdery inorganic filler (manufactured by Showa Denko KK) Then, 20 parts by weight of glass fiber (Mild Fiber, manufactured by Central Glass Co., Ltd.) was added thereto, and a phenol resin compounded liquid was prepared by stirring and mixing. The viscosity of the compounded liquid was measured, and the processability was evaluated. still,
Before blending the powdered inorganic filler in Examples 1 and 2,
A predetermined amount of an alkylol ammonium salt of polyester (manufactured by BYK Japan KK) shown in Table 1 was added.

In a resin mold reinforced with a two-part iron frame, a silicone rubber mold prepared by modeling a drawn log of a natural cedar having a tip diameter of 120 mm and a length of 3 m 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 opening 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, heat-treated in an oven at 60 ° C. for 5 hours, and further heated at 100 ° C. for 5 hours.
Heat treatment was carried out for a period of time, followed by sufficient cooling at room temperature, and the presence or absence of a cured part was visually evaluated. Table 1 shows the above results.

[0033]

[Table 1]

As a result, in Examples 1 and 2 in which the alkylol ammonium salt of the polyester was blended, the viscosity was low,
A beautiful phenol resin foam having good processability and having no hardened portions was obtained. On the other hand, the comparative example in which the alkylol ammonium salt of the polyester was not added had a high viscosity and was difficult to knead and process, and the foamed molded article had poor curing and defective foaming, and was unsatisfactory as a product. Was.

[0035]

As described above, in the method for foaming and curing a phenolic resin blended liquid containing at least a phenolic resin, a curing agent, a foaming agent, and a powdered inorganic filler, the block copolymer having an acid group in the blended liquid is used. By mixing the polymer alkylolamine salt, a viscosity-reducing effect is exhibited, the processability is improved, and the occurrence of a poorly cured portion is prevented.

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Claims (4)

[Claims] 1. A method for producing a phenolic resin foam obtained by foaming and curing a compounding liquid containing at least a phenolic resin, a foaming agent, a curing agent, and a powdery inorganic filler. A method for producing a phenolic resin foam, comprising a polymer alkylolamine salt. 2. The method for producing a phenolic resin foam according to claim 2, wherein the alkylolamine salt of the block copolymer having an acid group is an alkylolammonium salt of a block copolymer having an acid group. 3. The method according to claim 1, wherein at least one of the acid groups is a carboxyl group. 4. The method for producing a phenolic resin foam according to claim 1, wherein the block copolymer having an acid group has at least an ester bond in its structure.