JP5037051B2 - Phenolic resin foam and method for producing the same - Google Patents

Description

  The present invention relates to a phenol resin foam having a uniform fine cell structure and a method for producing the same.

  The phenol resin foam is produced by mixing a resol type phenol resin obtained by condensing phenol and formalin with an alkaline catalyst, a surfactant, a foaming agent, and a curing catalyst, and heating at room temperature or heating. The phenol resin foam obtained by this has an average cell diameter of 150 μm or less and a void area ratio in a cross-sectional area of 5% or less as proposed in Patent Document 1, It is required to further reduce the foam bubbles in foam, which greatly affects the foam, improve the uniformity of the bubbles, and stably reduce the void ratio. As a result, the foam physical properties are improved, especially the thermal conductivity. There was a need for improvement.

  On the other hand, as suggested in Patent Document 2, the recycling of phenolic resin foam scraps and waste materials generated in the manufacturing process from the viewpoint of material recycling is the reason for the production of phenolic resin foam from the viewpoint of recycling in recent years. This is considered a prerequisite. That is, there has been a strong demand for the development of a technology that simultaneously realizes recycling and improvement of foam physical properties, particularly improvement of thermal conductivity. In order to stably produce low thermal conductivity foams, it is necessary to make the foam bubbles finer, but that alone is not sufficient, and it is important to make the foams uniformly uniform. Form development has been considered difficult.

  In addition, as proposed in Patent Document 3, by adding ethylene trifluoride chloride, it is possible to achieve finer foaming of the phenol resin foam, but this increases costs and effectively uses recycled waste. There is a possibility that the effect of cost reduction may be offset, and it can be said that with this method, it is difficult to obtain a uniform bubble structure in which the standard deviation of the bubble diameter distribution is 7% or less of the average bubble diameter.

  Against this background, phenol resin foam powder for recycling, or inorganic powder such as aluminum hydroxide that is inexpensive as a bulking agent instead of phenol resin foam powder, and also phenol resin foam powder and inorganic By adding powder together, the amount of expensive phenolic resin used for foaming is reduced and costs are reduced, while foam properties, especially foam bubbles, are uniformly refined to improve thermal conductivity stably. Has been strongly desired.

International Publication No. 00/01761 Pamphlet JP 2004-323537 A Japanese Patent No. 3681307

  In the production of phenol resin foam, the present invention realizes cost reduction by using phenol resin foam, which is a waste material, or an inexpensive extender as part of the raw material, and has a fine and uniform cell structure. And it aims at providing the phenol resin foam with low heat conductivity.

  As a result of diligent investigations, the present inventors have specifically aimed at lowering the thermal conductivity of phenolic resin foam, and as a result, it has become a waste inorganic phenolic resin powder added for the purpose of cost reduction, or an inexpensive inorganic material added as a bulking agent. It has been found that the powder can also act as a solid foam nucleating agent to promote foam nucleation and play an important role in improving the tendency to refine the bubbles during foam production. Furthermore, in order to mold into a plate shape, it has been found that the object of the present invention can be achieved by optimizing the viscosity range of the foamable phenol resin composition when pressure is first applied from the vertical direction side, The present invention has been completed.

That is, a first aspect of the present invention is a phenol resin foam containing hydrocarbons having a density of 10 kg / m ³ or more and 100 kg / m ³ or less, having a closed cell ratio of 90% or more and a thermal conductivity of 0.015 W. / M · K or more and 0.019 W / m · K or less, the average bubble diameter is in the range of 20 μm or more and 150 μm or less, and the standard deviation of the bubble diameter distribution is 7% or less of the average bubble diameter. area ratio of voids to total cross-sectional area of a phenolic resin foam characterized by having a uniform fine cell structure Ru der 0.5% or less.

In phenolic foam of the present invention is in the range the average cell diameter below 100μm or 40 [mu] m, and it is preferable area ratio of voids to total cross-sectional area of the foam is less than 0.2%.

In the second aspect of the present invention, a foamable phenol resin composition containing at least a phenol resin, a surfactant, a hydrocarbon-containing foaming agent, and an acid curing catalyst is mixed, foamed, and cured using a mixer. Te a process for the preparation of phenolic foam, powder flat Hitoshitsubu diameter of 0.1μm or more 100μm or less were mixed at a ratio of less than 35 parts by weight or more 0.01 part by weight to 100 parts by weight of phenol resin The viscosity at 40 ° C. of the powder-containing phenol resin containing the phenol resin and the powder is 3000 to 300,000 mPa · s, and a foaming agent is mixed with the powder-containing phenol resin to obtain the powder-containing phenol resin and the foaming agent. foaming phenol after the resin composition was out distributor or al-discharge mixers, foamable off when applying the first pressure from the upper and lower direction to be formed into a plate shape including a The phenol resin foam production method is characterized in that the viscosity of the enol resin composition at 40 ° C. is adjusted to 50 mPa · s or more and 30,000 mPa · s or less.

  In the method for producing a phenol resin foam of the present invention, the viscosity at 40 ° C. of the foamable phenol resin composition when pressure is first applied from the up and down direction side to form the plate is 100 mPa · s or more and 10 or more. It is preferable to adjust to 000 mPa · s or less, and the powder is preferably phenol resin foam powder, inorganic powder, or a mixture thereof.

  According to the present invention, it is possible to provide a phenol resin foam with good performance and appearance while realizing a reduction in raw material costs by actively reusing phenol resin foam or using inexpensive powder as an extender. Can do.

  In the present invention, the phenol resin foam is a foam in which a large number of air bubbles are uniformly dispersed in a phenol resin formed by a curing reaction.

  The closed cell ratio of the phenol resin foam in the present invention is 90% or more, preferably 95% or more. If the closed cell ratio is less than 90%, there is a concern that the foaming agent in the phenolic resin foam is replaced with air and the heat insulation performance tends to be lowered.

The density of the phenol resin foam in the present invention can be selected as desired depending on conditions such as the ratio of the foaming agent and the oven temperature at the time of curing, but is 10 kg / m ³ or more and 100 kg / m ³ or less, preferably 20 kg / m. ³ or more and 60 kg / m ³ or less. When the density is less than 10 kg / m ³ , the mechanical strength such as compressive strength becomes small, the foam tends to be broken during the handling of the foam, and the surface brittleness also increases. On the other hand, if the density exceeds 100 kg / m ³ , the heat transfer of the resin part increases and the heat insulation performance may be lowered.

Phenolic foam of the present invention contains the hydrocarbon used as a blowing agent during manufacture in phenolic foam. In general, the foam is composed of a fine space generated in the resin by the evaporation of the foaming agent and a resin portion existing between the spaces. In the present invention, the space portion is called a bubble, and the resin portion is called a bubble wall.

  The average cell diameter of the phenol resin foam in the present invention is 20 μm or more and 150 μm or less, preferably 40 μm or more and 100 μm or less. If the average cell diameter is less than 20 μm, there is a limit to the thickness of the cell wall, which inevitably increases the foam density, resulting in an increase in the heat transfer rate of the resin part in the foam and the phenol resin foam. There is a risk that the heat insulation performance of will be insufficient. On the other hand, when the thickness exceeds 150 μm, the thermal conductivity due to radiation increases, and the heat insulating performance of the foam deteriorates. The small average cell diameter effectively affects the thermal insulation performance of the foam, but not only the average cell diameter is small, but also the uniform cell size improves the thermal insulation performance of the phenol resin foam stably. Can be made. For this purpose, the standard deviation of the bubble diameter distribution with respect to the average bubble diameter is preferably 7% or less. In the present invention, “the standard deviation of the cell diameter distribution with respect to the average cell diameter is 7% or less” makes it possible to further reduce the thermal conductivity of the phenol resin foam (0.019 W / m · K or less). I found it possible.

  A phenol resin foam has a relatively large (usually 1 mm or more in diameter) spherical or irregular void (hereinafter referred to as a void) in its interior. Usually, the void is formed by coalescence of bubbles, non-uniform vaporization of the foaming agent, or entrainment of air or the like in the foaming process. Further, even if the molding is performed after the foaming liquid is hardened, the bubble wall and the like are destroyed, leading to the generation of voids. This causes a decrease in compressive strength and is not preferable in appearance.

In the present invention, voids are defined as follows. That is, a cross section parallel to the front and back surfaces of the phenol resin foam is cut out, and voids existing in the cross section are measured by the method described later, and those having an area of 2 mm ² or more per void are defined as voids.

  The phenol resin foam of the present invention has very few voids, and the total area of the voids is 0.5% or less of the total area of the cross section. Therefore, the phenol resin foam according to the present invention has a very excellent effect that it can stably achieve low thermal conductivity and has a small variation in compressive strength. Further, since the bubbles are uniform, the appearance is extremely excellent. The amount of voids that can sufficiently satisfy the physical properties and appearance is 0.5% or less, preferably 0.2% or less.

The phenol resin foam according to the present invention preferably has no pores or dents on the cell wall cut surface and cell wall surface. This pore or dent formation mechanism is considered to be formed by the separation of volatile components such as water in the phenolic resin when the phenolic resin is cured, and then evaporates. The presence of the foaming agent and air is not desirable because the replacement of the foaming agent with air is promoted and the thermal conductivity may be deteriorated.

  The thermal conductivity of the phenol resin foam in the present invention is 0.015 W / m · K or more and 0.023 W / m · K or less, preferably 0.015 W / m · K or more and 0.021 W / m · K or less. . More preferably, it is 0.015 W / m · K or more and 0.019 W / m · K or less.

  The phenol resin foam according to the present invention comprises at least a phenol resin and a surfactant, a foaming agent containing a hydrocarbon, an acid curing catalyst, and a powder having an average particle size of 0.1 to 100 μm. It is obtained by dispersing and curing using an oven or the like.

  The phenol resin used in the present invention includes a resol type phenol resin synthesized by alkali metal hydroxide or alkaline earth metal hydroxide, a novolac type phenol resin synthesized by acid catalyst, and an ammonia resol type synthesized by ammonia. Examples thereof include a benzyl ether type phenol resin synthesized with a phenol resin or lead naphthenate, etc. Among them, a resol type phenol resin is preferable. The resol-type phenol resin is polymerized by heating phenol and formalin as raw materials at a temperature range of 40 to 100 ° C. with an alkali catalyst. Moreover, you may add additives, such as urea, at the time of resole resin polymerization as needed. In the case of adding urea, it is more preferable to mix urea methylolated with an alkali catalyst in advance into the resole resin. Since the resole resin after synthesis usually contains excess water, the amount of water suitable for foaming is adjusted during foaming. In addition, aliphatic hydrocarbons or alicyclic hydrocarbons having a high boiling point or mixtures thereof, diluents for viscosity adjustment such as ethylene glycol and diethylene glycol, and other additives may be added to the phenol resin as necessary. it can.

  The powder having an average particle size of 0.1 μm or more and 100 μm or less used in the present invention is largely cured like an inorganic powder such as phenol resin foam and aluminum hydroxide as a bulking agent on the premise of material recycling. Any powder that does not affect the reaction and has poor chemical reactivity with the phenol resin is defined without particular limitation. These powders are considered as solid foam nucleating agents, which promote the formation of foam nuclei after the addition of the foaming agent and play an important role in the refinement of bubbles during foam production.

The phenol resin foam powder in the present invention is a powder obtained by pulverizing a phenol resin foam, and its bulk density is preferably 100 kg / m ³ or more and 300 kg / m ³ or less, more preferably 130 kg / m ^3. It is 250 kg / m ³ or less. When the bulk density is less than 100 kg / m ³ , the viscosity when mixed with the phenol resin becomes high and difficult to handle, and a large amount of energy is required to make it 300 kg / m ³ or more, which is not practical.

  The method for pulverizing the phenol resin foam used as a powder in the present invention is not particularly limited, but a pulverizer such as a rolling ball mill, a rolling rod mill, a vibrating ball mill, a vibrating rod mill, a pan mill, a roller mill, or a high-speed rotary mill is used. In particular, in order to increase the bulk density of the phenol resin foam powder, it is desirable to use a pulverizer having a large compaction effect of the phenol resin foam powder, such as a vibration ball mill and a vibration rod mill. However, mixing of the face material into the foam powder may cause clogging of each device and piping retention part in the manufacturing process, so it is necessary to minimize the mixing of the face material into the foam powder. is there. For this reason, it is important to separate the face material from the foam manually or to use a device that reduces the amount of the face material mixed into the foam, such as a rolling ball mill.

  The inorganic powder used as the powder in the present invention is aluminum hydroxide powder, aluminum oxide powder, calcium carbonate powder, talc, clay (kaolin), quartzite powder, quartz sand, mica, calcium silicate powder, wollastonite And inorganic powders such as glass powder, glass beads, fly ash, silica fume, gypsum powder, borax, slag powder, alumina cement, and Portland cement. These may be used alone, in combination of two or more, or may be used in combination with phenol resin foam powder.

  The particle size of the powder mixed with the foamable phenolic resin composition may cause not only operational problems such as clogging of the filter in the piping when large particle size powder is mixed, but also foam formation of foam This is not preferable because it is difficult to have a fine and uniform cell structure. Therefore, it is desirable to remove large powder from the phenol resin foam powder using a sieve having an opening of 500 μm or less after pulverization.

  The average particle size of the powder is not preferable if a large amount of powder exceeding 100 μm is present, because it affects the foam formation of the foam and it becomes difficult to form a fine uniform cell structure. Moreover, in order to make it less than 0.1 micrometer, a lot of energy is needed and it is not preferable. Therefore, powder having an average particle size of 0.1 μm or more and 100 μm or less is used.

  The amount of the powder mixed with the foamable phenol resin composition is 0.01 parts by weight or more and 35 parts by weight or less with respect to 100 parts by weight of the phenol resin. If the amount of powder added is too large, the viscosity of the foamable phenolic resin composition will increase and its fluidity will decrease. Therefore, considering the fluidity in the flow-through piping of the foamable phenolic resin composition, The addition amount is 35 parts by weight or less with respect to 100 parts by weight of the phenol resin. Further, if the amount of the powder added exceeds 35 parts by weight, the density of the phenol resin foam tends to increase, and when trying to make the density of the phenol resin foam constant, the compressive strength tends to decrease, and the thermal conductivity of the foam Is not preferable because it tends to deteriorate. On the other hand, if the addition amount is less than 0.01 parts by weight, the effect of adding powder (powder recycling, foam cost reduction, foam performance improvement) cannot be obtained sufficiently, which is not preferable.

  Since the phenol resin foam generally contains a catalyst-derived free acid, when a large amount of the phenol resin foam powder is added to the foamable phenol resin composition as a powder, the foamable phenol resin composition reacts to increase the molecular weight. May be difficult to handle or harden. In order to prevent this, if necessary, treatment such as washing of phenol resin foam powder can be performed. For washing, water, a weak alkaline aqueous solution, or the like can be used.

  The starting molar ratio of phenols to aldehydes in the phenolic resin used in the present invention is preferably from 1: 1 to 1: 4.5, more preferably from 1: 1.5 to 1: 2.5. In the present invention, the phenols preferably used in the synthesis of the phenol resin include phenol itself and other phenols. Examples of other phenols include resorcinol, catechol, o-, m- and p-. Examples include cresol, xylenols, ethylphenols, and p-tertbutylphenol. Dinuclear phenols can also be used.

  The aldehydes preferably used in the present invention are formaldehyde itself and other aldehydes. Examples of other aldehydes include glyoxal, acetaldehyde, chloral, furfural, benzaldehyde and the like. Urea, dicyandiamide, melamine, etc. may be added as additives. In the present invention, when these additives are added, the phenol resin refers to the one after the additives are added.

  When a resol type phenol resin is used, the viscosity at 40 ° C. is preferably 3,000 mPa · s or more and 100,000 mPa · s or less, more preferably 5,000 mPa · s or more and 50,000 mPa · s or less. The water content is preferably 3% by weight or more and 30% by weight or less.

  The mixing method of the said powder and a phenol resin is not specifically limited, You may mix using a hand mixer, a pin mixer, etc., You may use a biaxial extruder, a kneader, etc. The stage of mixing the powder with the phenol resin is not particularly limited, and when the phenol resin is synthesized, it may be added together with the raw materials, or before and after the addition of each additive after the synthesis is completed. The viscosity may be adjusted, or may be mixed with a surfactant or / and a foaming agent. However, adding the powder to the phenolic resin increases the overall viscosity. Therefore, when adding the powder to the phenolic resin before viscosity adjustment, the viscosity adjustment of the phenolic resin is estimated based on the amount of water. Preferably it is done. Moreover, you may mix with the foamable phenol resin composition containing a phenol resin, surfactant, the foaming agent containing a hydrocarbon, and an acid curing catalyst. Furthermore, the required amount of powder may be mixed with the phenol resin, or a high concentration of powdered phenol resin may be prepared as a master batch, and the required amount may be added to the phenol resin.

  The viscosity at 40 ° C. of the phenol resin containing the powder is 3,000 mPa · s or more and 300,000 mPa · s or less in consideration of the load of the apparatus due to the increase in pressure in the flow-through piping of the foamable phenol resin composition. It is preferably 5,000 mPa · s or more and 100,000 mPa · s or less, and more preferably 10,000 mPa · s or more and 50,000 mPa · s or less. The water content is preferably 3% by weight or more and 30% by weight or less.

  The surfactant and the foaming agent may be added in advance to the phenol resin, or may be added simultaneously with the acid curing catalyst.

  As the surfactant used in the present invention, those generally used for the production of phenol resin foams can be used. Among them, nonionic surfactants are effective, for example, a copolymer of ethylene oxide and propylene oxide. Alkylene oxides, condensation products of alkylene oxides and castor oil, condensation products of alkylene oxides with alkylphenols such as nonylphenol and dodecylphenol, fatty acid esters such as polyoxyethylene fatty acid esters, polydimethylsiloxane and the like Silicone compounds and polyalcohols are preferred. One type of surfactant may be used, or two or more types may be used in combination. Moreover, although there is no restriction | limiting in particular about the usage-amount, It uses preferably in the range of 0.3-10 weight part per 100 weight part of phenol resin compositions.

  The hydrocarbon content contained in the blowing agent used in the present invention is desirably 50% by weight or more, more preferably 70% by weight or more, and particularly preferably 90% by weight or more. If the hydrocarbon content is less than 50% by weight, the global warming potential of the foaming agent is undesirably high. As the hydrocarbon contained in the foaming agent used in the production of the phenol resin foam of the present invention, a cyclic or chain alkane, alkene, or alkyne having 3 to 7 carbon atoms is preferable, and foaming performance and chemical stability (2 From the viewpoint of the thermal conductivity of the compound itself and a compound itself, an alkane or cycloalkane having 4 to 6 carbon atoms is more preferable. Specific examples include normal butane, isobutane, cyclobutane, normal pentane, isopentane, cyclopentane, neopentane, normal hexane, isohexane, 2,2-dimethylbutane, 2,3-dimethylbutane, cyclohexane, and the like. Among them, normal pentane, isopentane, cyclopentane, neopentane pentanes and normal butane, isobutane, cyclobutane butanes have comfortable foaming characteristics in the production of the phenol resin foam of the present invention, and have a comparative thermal conductivity. It is particularly preferable because of its small size.

  In the present invention, two or more of these hydrocarbons can be mixed and used. Specifically, a mixture of 5 to 95% by weight of pentanes and 95 to 5% by weight of butanes is preferable because it exhibits good heat insulation characteristics in a wide temperature range. Among them, normal pentane or a combination of isopentane and isobutane has high heat insulation performance in a wide range from a low temperature range to a high temperature range, and it can be said that these compounds are advantageous in use because they are inexpensive. In addition, the combined use of hydrocarbons as foaming agents and HFCs such as 1,1,1,2-tetrafluoroethane, 1,1-difluoroethane, and pentafluoroethane having a low boiling point can improve the low temperature characteristics of the phenol resin foam. Although it is possible, since the global warming potential as a mixed foaming agent becomes large, it cannot be said that it is so much preferable to use HFC together. Further, a low boiling point substance such as nitrogen, helium, argon, air may be added to the foaming agent as the foam nucleating agent.

  The acid curing catalyst used in the present invention is not particularly limited, but when an acid containing water is used, there is a possibility that the foam cell wall may be destroyed. Therefore, phosphoric anhydride and aryl sulfonic anhydride are considered preferable. Examples of the aryl sulfonic anhydride include toluene sulfonic acid, xylene sulfonic acid, phenol sulfonic acid, substituted phenol sulfonic acid, xylenol sulfonic acid, substituted xylenol sulfonic acid, dodecyl benzene sulfonic acid, benzene sulfonic acid, and naphthalene sulfonic acid. May be used alone or in combination of two or more. Further, resorcinol, cresol, saligenin (o-methylolphenol), p-methylolphenol and the like may be added as a curing aid. In addition, these curing catalysts may be diluted with a solvent such as ethylene glycol or diethylene glycol.

  After the acid curing catalyst is added to the phenol resin containing powder, the acid curing catalyst is uniformly dispersed as quickly as possible using a pin mixer or the like. The amount of foaming agent used varies depending on the type. For example, when a mixture of 50% by weight of isopentane and 50% by weight of isobutane is used as the foaming agent, it is preferably 2 parts by weight or more and 20 parts by weight or less, more preferably 4 parts by weight or more and 17 parts by weight or less with respect to 100 parts by weight of the phenol resin. Used in less than part.

  The amount of the acid curing catalyst used varies depending on the type, and when phosphoric anhydride is used, it is preferably 5 to 30 parts by weight, more preferably 8 to 25 parts by weight, with respect to 100 parts by weight of the phenol resin. Used in: When a mixture of 60% by weight of paratoluenesulfonic acid monohydrate and 40% by weight of diethylene glycol is used, it is preferably 3 parts by weight or more and 30 parts by weight or less, more preferably 5 parts by weight or more with respect to 100 parts by weight of the phenol resin. Used at 20 parts by weight or less.

  In the present invention, a foamable phenol resin composition containing at least a phenol resin, a powder, a surfactant, an acid curing catalyst, and a foaming agent is mixed using a mixer, and the foamable phenol resin is distributed from a distributor of the mixer. After discharging the composition, the viscosity at 40 ° C. of the foamable phenol resin composition when pressure is first applied from the vertical direction side to form a plate is 50 mPa · s or more and 30,000 mPa · s or less. More preferably, it is 100 mPa · s or more and 10,000 mPa · s or less. When the viscosity exceeds 30,000 mPa · s, the degree of progress of the curing reaction is high, so that the bubble wall is easily broken and voids are easily generated, and the bubble diameter distribution becomes non-uniform, resulting in thermal conductivity. This is not preferable in terms of appearance. On the other hand, when molding is performed at less than 50 mPa · s, curing hardly progresses, and the apparatus used for molding is soiled and leads to a decrease in yield due to loss of resin adhering to the apparatus. Therefore, it is not preferable. Further, when the viscosity is 100 mPa · s or more and 10,000 mPa · s or less, a phenol resin foam having a thermal conductivity of 0.019 W / m · K or less can be produced.

  Examples of the method for adjusting the viscosity to a range of 50 mPa · s to 30,000 mPa · s mainly include a method of adjusting the temperature of the foamable phenol resin composition in the mixer. When the temperature is high, the reaction of the foamable resin composition proceeds, whereby the viscosity at the time of molding into a plate shape is likely to increase. When the temperature is low, the reaction of the foamable resin composition proceeds. As a result, the viscosity at the time of forming into a plate shape is difficult to increase. The temperature can be adjusted by appropriately adjusting the blending ratio of each component of the foamable resin composition, the stirring rotation speed of the mixer, and the cooling method (cooling temperature and cooling water flow rate) of the mixer.

  The foaming phenol resin composition is mixed using a mixer, and after the foaming phenol resin composition is discharged from the distribution section, the pressure is first applied from the vertical direction side to form a plate. There are various methods depending on the production purpose, such as a method using a slat type double conveyor, a method using a metal roll or a steel plate, and a method using a combination of these. Among these, for example, when using a slat type double conveyor, after discharging the foamable phenolic resin composition from the distributor of the mixer onto the bottom surface material that continuously travels, the top surface that also travels continuously The foamable phenolic resin composition is continuously guided into the slat type double conveyor while being covered with a material, and then heated and foamed while being adjusted to a predetermined thickness by applying pressure from the vertical direction while heating. Molded into a plate shape. As the face material used here, a flexible face material is preferable, and a synthetic fiber nonwoven fabric or paper is most preferable from the viewpoint of easy handling as a foam laminate and economical efficiency.

  The curing temperature is preferably 40 ° C. or higher and 130 ° C. or lower, more preferably 60 ° C. or higher and 110 ° C. or lower. Curing may be performed in one stage, or may be cured in several stages by changing the curing temperature according to the degree of curing.

  Next, the phenol resin, the composition of phenol resin foam, the structure, the evaluation method of characteristics, and the structure of phenol resin foam powder in the present invention will be described.

[Viscosity of phenolic resin]
A rotational viscometer (manufactured by Toki Sangyo Co., Ltd., R-100 type, rotor part 3 ° × R-14) was used, and the measured value was obtained after stabilization at 40 ° C. for 3 minutes. In addition, the viscosity of the foamable phenolic resin composition at the time of forming into a plate is evaluated by eliminating the influence of the increase in viscosity due to curing of the resin as much as possible. The measured value was used.

[Moisture content of phenolic resin]
Dissolve the phenol resin in dehydrated methanol (manufactured by Kanto Chemical Co., Inc.) in the range of 3 to 7% by weight, measure the water content of the solution, and determine the water content in the phenol resin. Asked. For the measurement, a Karl Fischer moisture meter (manufactured by Kyoto Electronics Industry Co., Ltd., MKC-510) was used.

〔The bulk density〕
The bulk density of the phenol resin foam powder was measured according to JIS-K-6911.

[Average particle size of powder]
The average particle size of the phenol resin foam powder is to disperse the powder uniformly in water using a laser diffraction light scattering type particle size distribution measuring device (manufactured by Nikkiso Co., Ltd., Microtrac HRA; 9320-X100). Measurement was performed after ultrasonic treatment for 1 minute.

[Form density]
A value obtained by measuring a weight and an apparent volume by removing a face material and a siding material of a 20 cm square phenol resin foam as a sample, and measured according to JIS-K-7222.

[Closed cell ratio]
A cylindrical sample with a diameter of 35 mm to 36 mm is pierced with a cork borer from a phenolic resin foam, cut to a height of 30 mm to 40 mm, and then sampled according to the standard usage method of an air-comparing hydrometer (Tokyo Science Co., Ltd. model 1,000). Measure the volume. The value obtained by subtracting the volume of the bubble wall calculated from the sample weight and the resin density from the sample volume was divided by the apparent volume calculated from the outer dimensions of the sample, and was measured according to ASTM-D-2856. Here, the density of the phenol resin was 1.3 kg / L.

〔Thermal conductivity〕
A phenol resin foam sample was measured in a 200 mm square, a low temperature plate at 5 ° C., and a high temperature plate at 35 ° C. according to a JIS-A-1412 flat plate heat flow meter method.

[Average bubble diameter]
This is a value obtained by dividing four straight lines of 9 cm length on the 50 times magnified photograph of the foam cross section and dividing 1,800 μm by the average number of bubbles crossed by each straight line, according to JIS-K-6402 This is the average value calculated from the number of cells measured.

[Standard deviation of bubble size distribution]
Draw 12 straight lines of 9cm length on the 50x magnified photograph of the cross section of the foam, and for each straight line, divide 1,800μm by the number of bubbles crossed by each straight line. The standard deviation was defined as the ratio of the standard deviation to the average bubble diameter.

〔void〕
Cut almost the center in the thickness direction of the phenolic resin foam sample parallel to the front and back surfaces, and take a 200% enlarged color copy (each length is doubled, that is, the area is quadrupled) over a range of 100 mm x 150 mm. A void area of 1 mm × 1 mm square having 8 squares or more was integrated with a transparent graph paper, and the area fraction was calculated. That is, since an enlarged copy is taken, these 8 squares correspond to an area of 2 mm ^{2 in} an actual foam cross section. These samples with the same production conditions were evaluated 12 times, and the average value was used as the representative value of the production condition samples.

[Presence of pores in the bubble wall]
An electron microscope is used to observe a 5000-fold photograph of the foam cross-section to confirm the presence or absence of holes or dents. For example, in FIG. 1, a large number of holes or dents 3 are observed on the cross section (bubble wall cut surface 2) of the resin part surrounded by three bubbles and the internal bubble surface (bubble wall surface 1). This hole or dent is usually 5 μm or less in diameter. FIG. 2 is a schematic diagram for explaining the cell wall structure of the phenol resin foam. On the other hand, it can be confirmed in FIG. 3 that these holes or dents are not present at all.

  EXAMPLES Next, although an Example and a comparative example demonstrate this invention further in detail, this invention is not limited to these.

<Synthesis of phenolic resin>
The reactor was charged with 3500 kg of 52 wt% formaldehyde and 2510 kg of 99 wt% phenol, stirred with a propeller rotary stirrer, and the temperature inside the reactor was adjusted to 40 ° C. with a temperature controller. Next, the reaction was carried out by increasing the temperature while adding a 50 wt% aqueous sodium hydroxide solution. When the Ostwald viscosity reached 60 centistokes (measured value at 25 ° C.), the reaction solution was cooled, and 570 kg of urea (corresponding to 15 mol% of the charged amount of formaldehyde) was added. Thereafter, the reaction solution was cooled to 30 ° C., and the pH was neutralized to 6.4 with a 50 wt% aqueous solution of paratoluenesulfonic acid monohydrate.

  When this reaction solution was dehydrated at 60 ° C. and the viscosity and water content were measured, the viscosity at 40 ° C. was 5,800 mPa · s, and the water content was 5% by weight. This is designated as phenol resin A-U.

Example 1
Phenolic resin AU: 100 parts by weight of ethylene oxide-propylene oxide block copolymer (manufactured by BASF, Pluronic F-127) as a surfactant was mixed at a ratio of 2.0 parts by weight.

Phenol resin foam (Asahi Kasei Construction Materials Co., Ltd., Neomafoam) mill ends are stripped and coarsely pulverized with a rolling ball mill (dry type, diameter 900 mm × 1,500 mm), and then sieved (opening: 1). After removing the face material by 2 mm), it is compacted and pulverized using a vibration ball mill (dry type, inner diameter 150 mm, 1 cylinder 15.5 L × 2 cylinders), and large particles are obtained with a sieve (screen opening: 0.5 mm). After removing the diameter foam powder, a phenol resin foam powder having a bulk density of 183 kg / m ³ was produced. When this phenol resin foam powder was measured with a laser diffraction light scattering particle size distribution analyzer, the average particle size was 26.4 μm.

  8 parts by weight of this powder was added to 100 parts by weight of phenol resin AU and kneaded by a twin screw extruder (manufactured by Technobel). 7 parts by weight of a mixture of 50% by weight of isopentane and 50% by weight of isobutane as a blowing agent, and a mixture of 80% by weight of xylene sulfonic acid and 20% by weight of diethylene glycol as an acid curing catalyst with respect to 100 parts by weight of phenol resin containing phenol resin foam powder. The composition consisting of parts by weight was supplied to a mixing head whose temperature was adjusted to 25 ° C., and supplied to the moving lower surface material through a multiport distribution pipe. The mixer (mixer) used was the one disclosed in JP-A-10-225993. That is, there is a resin composition obtained by adding a surfactant and powder to a phenol resin on the upper side surface, and an introduction port for a foaming agent. I have. The part after the stirring part is connected to a nozzle for discharging the foam. That is, the part up to the catalyst inlet is the mixing part (A), the catalyst inlet to the stirring end part is the mixing part (B), and the stirring end part to the nozzle is the distribution part (C). The distribution part (C) has a plurality of nozzles at the tip, and is designed so that the mixed foamable phenolic resin composition is uniformly distributed. Further, a temperature sensor (D) is set on the central side surface of the mixing part (A) and the lowermost part of the mixing part (B) so that the temperature in the system can be measured. Furthermore, each mixing part and the distribution part are each provided with the jacket for temperature control for enabling temperature adjustment. The temperature measured by this temperature sensor (D) was 36.4 ° C.

A polyester nonwoven fabric (“Spunbond E05030” manufactured by Asahi Kasei Fibers Co., Ltd., weighing 30 g / m ² , thickness 0.15 mm) was used as the face material.

  The foamable phenolic resin composition supplied on the lower surface material is coated with the upper surface material, and at the same time, sandwiched between the upper and lower surface materials, sent to a 85 ° C. slat type double conveyor, and cured with a residence time of 15 minutes. And then cured in an oven at 110 ° C. for 2 hours to obtain a phenolic resin foam. The slat type double conveyor used at this time is designed to release moisture generated during curing to the outside. The foamable phenolic resin composition coated with the upper and lower surface materials was formed into a plate shape by applying moderate pressure through the surface material from above and below with a slat type double conveyor. The viscosity at 40 ° C. of the foamable phenol resin composition when pressure was applied from the vertical direction side was 8,800 mPa · s.

(Example 2)
5 parts by weight of phenol resin foam powder is added to 100 parts by weight of phenol resin AU, and the temperature measured by the temperature sensor (D) is 27.3 ° C. A phenol resin foam was obtained in the same manner as in Example 1 except that the viscosity at 40 ° C. of the foamable phenol resin composition when pressure from the vertical direction side was applied was changed to 50 mPa · s.

(Example 3)
The temperature measured by the temperature sensor (D) is 46.4 ° C., and the viscosity at 40 ° C. of the foamable phenolic resin composition when pressure from the up and down direction when molding into a plate shape is applied, A phenol resin foam was obtained in the same manner as in Example 1 except that the pressure was changed to 28,000 mPa · s.

Example 4
Phenol resin foam (made by Asahi Kasei Construction Materials Co., Ltd., Neomafoam) end material is peeled and coarsely pulverized with a rolling ball mill (dry type, diameter 900 mm × 1,500 mm), and then sieve (screen opening: 1.2 mm) ) To remove the face material, and then use two types of sieves (first stage sieve opening: 0.25 mm, second stage sieve opening: 0.063 mm) to become the first stage sieve below, and The foam powder on the second stage sieve is collected and used, the temperature measured by the temperature sensor (D) is 38.9 ° C., and the pressure from the up and down direction when forming into a plate shape A phenolic resin foam was obtained in the same manner as in Example 1 except that the viscosity at 40 ° C. of the foamable phenolic resin composition was changed to 15,000 mPa · s. The resulting phenol resin foam powder had a bulk density of 103 kg / m ³ and an average particle size of 98.1 μm.

(Example 5)
Phenol resin foam (Asahi Kasei Construction Materials Co., Ltd., Neomafoam) mill ends are stripped and coarsely pulverized with a rolling ball mill (dry type, diameter 900 mm × 1,500 mm), and then sieved (opening: 1). After removing the face material by 2 mm), it is compacted and pulverized using a vibration ball mill (dry type, inner diameter 150 mm, 1 cylinder 15.5 L × 2 cylinders), and large particles are obtained with a sieve (screen opening: 0.5 mm). After removing the foam powder of the diameter, the bulk density of the phenol resin foam to be used is 284 kg / m ³ , the temperature measured by the temperature sensor (D) is 30.8 ° C. A phenol resin foam was obtained in the same manner as in Example 1, except that the viscosity at 40 ° C. of the foamable phenol resin composition when pressure from the vertical direction was applied was changed to 900 mPa · s. In addition, the average particle diameter of the obtained phenol resin foam powder was 15.4 μm.

(Example 6)
5 parts by weight of phenol resin foam powder is added to 100 parts by weight of phenol resin AU, 7 parts by weight of cyclopentane is used as a blowing agent, and the temperature measured by the temperature sensor (D) is 29.5. The same as in Example 1 except that the viscosity at 40 ° C. of the foamable phenolic resin composition when the pressure from the up and down direction at the time of molding into a plate was applied was changed to 750 mPa · s. Thus, a phenol resin foam was obtained.

(Example 7)
Phenol resin AU: The powder kneaded with respect to 100 parts by weight is aluminum hydroxide powder (manufactured by Sakai Kogyo Co., Ltd., H-710, average particle size 1.0 μm), and the amount added is 3 parts by weight. The viscosity measured at 40 ° C. of the foamable phenolic resin composition when the temperature measured by the temperature sensor (D) is 34.0 ° C. and pressure from the up and down direction when molding into a plate shape is applied. A phenol resin foam was obtained in the same manner as in Example 1 except that the pressure was changed to 3,600 mPa · s.

(Example 8)
Phenol resin AU: The powder kneaded with respect to 100 parts by weight is aluminum hydroxide powder (manufactured by Sakai Kogyo Co., Ltd., B-325, average particle size 23.0 μm), and the amount added is 34 parts by weight. The viscosity measured at 40 ° C. of the foamable phenolic resin composition when the temperature measured by the temperature sensor (D) is 45.2 ° C. and pressure is applied from the vertical direction when forming into a plate shape. A phenol resin foam was obtained in the same manner as in Example 1 except that the pressure was changed to 28,700 mPa · s.

Example 9
Phenol resin AU: 5 parts by weight of phenol resin foam powder (bulk density: 183 kg / m ³ , average particle size: 26.4 μm) described in Example 1 was mixed with 100 parts by weight of the powder. It is 3 parts by weight of aluminum powder (manufactured by Sakai Kogyo Co., Ltd., B-325, average particle size 23.0 μm), the temperature measured by the temperature sensor (D) is 32.4 ° C., and is molded into a plate shape A phenol resin foam was obtained in the same manner as in Example 1 except that the viscosity at 40 ° C. of the foamable phenol resin composition when applying pressure from the up and down direction was changed to 1,200 mPa · s. .

(Example 10)
Phenol resin AU: The powder kneaded with respect to 100 parts by weight is calcium carbonate powder (manufactured by Wako Pure Chemical Industries, Ltd., average particle size 5.2 μm), the amount added is 2 parts by weight, and the temperature The viscosity measured at 40 ° C. of the foamable phenol resin composition when the pressure measured from the sensor (D) is 30.5 ° C. and pressure from the up and down direction when forming into a plate shape is 900 mPa · s. A phenolic resin foam was obtained in the same manner as in Example 1 except for changing to

(Comparative Example 1)
Phenol resin AU: Powder added to 100 parts by weight is not added, the temperature measured by the temperature sensor (D) is 47.0 ° C. A phenol resin foam was obtained in the same manner as in Example 1 except that the viscosity at 40 ° C. of the foamable phenol resin composition when pressure was applied was changed to 41,800 mPa · s.

(Comparative Example 2)
The temperature measured by the temperature sensor (D) is 50.4 ° C., and the viscosity at 40 ° C. of the foamable phenolic resin composition when pressure is applied from the vertical direction when molding into a plate shape, A phenol resin foam was obtained in the same manner as in Example 1 except that the pressure was changed to 46,400 mPa · s.

(Comparative Example 3)
The temperature measured by the temperature sensor (D) is 51.0 ° C., and the viscosity at 40 ° C. of the foamable phenolic resin composition when pressure from the up and down direction at the time of molding into a plate shape is applied, A phenol resin foam was obtained in the same manner as in Example 7 except that the viscosity was changed to 43,900 mPa · s.

  Characteristics of the powder added to the foamable phenolic resin composition used in the above Examples and Comparative Examples, and the viscosity of the foamable phenolic resin composition at 40 ° C. when pressure is first applied from the vertical direction side Table 1 shows the evaluation results of the obtained phenolic resin foam, and Table 2 shows the evaluation results.

It is an example of the electron micrograph of the cell wall cross section of the phenol resin foam in which a hole or a dent exists. It is a cell wall structure schematic diagram of the phenol resin foam of FIG. 1 with a hole or a dent. It is an example of the electron micrograph of the cell wall cross section of the phenol resin foam which does not have a hole or a dent.

Explanation of symbols

1 Cell wall surface 2 Cell wall cut surface 3 Hole or dent

Claims (6)

A phenol resin foam containing a hydrocarbon having a density of 10 kg / m ³ or more and 100 kg / m ³ or less, having a closed cell ratio of 90% or more and a thermal conductivity of 0.015 W / m · K or more and 0.019 W. / M · K or less, the average cell diameter is in the range of 20 μm or more and 150 μm or less, the standard deviation of the cell diameter distribution is 7% or less of the average cell diameter, and the void area ratio in the cross-sectional area of the foam There phenolic foam characterized by having a uniform fine cell structure Ru der 0.5% or less. Average bubble diameter is in the range of 40μm or 100μm or less, and a phenol resin foam according to claim 1 area ratio of voids to total cross-sectional area of the foam is less than 0.2%. A method for producing a foam by mixing a foamable phenol resin composition containing at least a phenol resin, a surfactant, a hydrocarbon-containing foaming agent, and an acid curing catalyst, using a mixer, and foaming and curing. in the powder flat Hitoshitsubu diameter of 0.1μm or more 100μm or less were mixed at a ratio of less than 35 parts by weight or more 0.01 parts by weight per 100 parts by weight of the phenolic resin comprises a phenolic resin and powder Foamable phenolic resin composition having a powdery phenolic resin having a viscosity at 40 ° C. of 3000 to 300,000 mPa · s, a foaming agent mixed with the powdery phenolic resin, and the powdery phenolic resin and the foaming agent after allowed out distributor or et ejection mixer, put into 40 ° C. of foamable phenolic resin composition when adding first pressure from the upper and lower direction to be formed into a plate-like Adjusting the viscosity to 50 mPa · s or more and 30,000 mPa · s or less.   4. The viscosity at 40 ° C. of the foamable phenolic resin composition when pressure is first applied from the vertical direction side in order to form the plate shape is adjusted to 100 mPa · s or more and 10,000 mPa · s or less. The manufacturing method of the phenol resin foam of description.   The method for producing a phenol resin foam according to claim 3 or 4, wherein the powder is a phenol resin foam powder.   The method for producing a phenol resin foam according to claim 3 or 4, wherein the powder is an inorganic powder.

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