JP5002825B2 - Method for producing inorganic foam - Google Patents

Description

  The present invention relates to a method for producing an inorganic foam, and more particularly relates to a method for producing an inorganic foam having heat insulating properties, nonflammability, etc., light weight and sufficient mechanical strength.

  Foams foamed by closed cells are lightweight and excellent in heat insulation, and are widely used in heat insulation materials for various devices and buildings. In particular, among such foams, vinyl chloride resin foams are excellent in terms of chemical resistance, mechanical strength, etc., and are widely used.

However, although this vinyl chloride resin is flame-retardant, it is not nonflammable. In addition, it is relatively weak against heat and has a drawback of large volume shrinkage in a high temperature atmosphere.
Therefore, in order to improve this point, inorganic foams have been developed in which an inorganic substance capable of suppressing volume shrinkage even when heated is mixed and foamed.

  For example, an inorganic material filler having crystal water in the molecule is mixed with a vinyl chloride resin, heated to generate water vapor, and foamed. However, such a foam cannot be uniformly dispersed and foamed when a large amount of the inorganic material filler is mixed, and it is difficult to blend the inorganic material filler in an amount of 25% by weight or more.

  Also, based on inorganic material fillers such as calcium carbonate and talc, vinyl chloride resin, foaming agent and organic solvent are added to this, then kneaded with a kneader, and the resulting kneaded material is filled into a mold and heated and foamed. What was made to know is known (for example, patent document 1).

  According to the method described in Patent Document 1, it is possible to obtain a foam containing an inorganic substance filler in a high ratio. However, such foam has a small total calorific value at the time of combustion and a maximum heat generation rate, but shrinkage and cracking are remarkable, and as a non-combustible material and quasi-incombustible material shown in Article 2, Item 9 of the Building Standard Law. It did not pass the exothermicity test by the cone calorimeter which is a performance evaluation test.

Also, using inorganic fibers such as glass fiber and rock wool and metal hydroxide having a diameter of 1 μm or more, 100 parts by weight of vinyl chloride resin having an average polymerization degree of 2400, 100 parts by weight of solvent and 6 parts by weight of dibasic lead stearate It has been reported that an inorganic foam containing an inorganic substance at a high ratio is produced using a specific solvent having a maximum torque of 4 to 25 N · m when kneading a mixture composed of (Patent Document 2). .
However, in this case, according to the knowledge of the inventors, when a large amount of aluminum hydroxide is added as a metal hydroxide, it becomes difficult to obtain a low-density foam or the dehydration reaction of aluminum hydroxide occurs. There is a problem that the degree of shrinkage and cracking increases due to the influence. This does not pass the performance evaluation test in the above exothermic test.

  Further, an inorganic lightweight foam using a fiber diameter of 5 μm or less and a melting point of 1000 ° C. or more as an inorganic fiber is known (Patent Document 3). However, this inorganic foam also does not pass the performance evaluation test in the exothermic test.

  In view of these circumstances, the present inventors have studied from various viewpoints and previously proposed a method for producing an inorganic foam in which fumed silica is further added to a mixture of a vinyl chloride resin and an inorganic filler, a foaming agent and an organic solvent. (Japanese Patent Application No. 2004-147527).

JP-A-11-349720 Japanese Patent Publication No. 7-47658 Japanese Patent Publication No. 7-47511

  The present invention has been made in order to solve the problems of the above-mentioned conventional inorganic foam, and its purpose is to suppress volume shrinkage during combustion, and it is lightweight, heat insulating, water resistant, and sound absorbing. It is desirable to provide a production method capable of obtaining an inorganic foam having excellent mechanical strength and improved nonflammability.

  The inventors of the present invention have made extensive studies to achieve the above-mentioned object, and have further studied the previous application, and adding a predetermined amount of inorganic fiber whisker and a specific inorganic filler without using fumed silica. It has been found that an inorganic foam having improved nonflammability, which can reduce the total calorific value and maximum heat generation rate during combustion, and can suppress shrinkage and cracking of the surface, has been completed. It was.

That is, the present invention comprises (1) (a) 5 to 30 parts by weight of vinyl chloride resin, (b) 10 to 30 parts by weight of aluminum hydroxide or magnesium hydroxide having an average particle size of 0.5 to 20 μm , c) 1 to 25 parts by weight of potassium titanate whisker and / or basic magnesium sulfate whisker having a fiber length of 1 μm to 40 μm and a fiber diameter of 0.1 μm to 5 μm , (d) ditrioxide as a flame retardant 0.5 to 3 parts by weight of antimony , (e) other inorganic fillers (total of (a) to (e) is 100 parts by weight), a foaming agent and an organic solvent are kneaded, and the kneaded product is pressurized. The gist of the present invention is a method for producing an inorganic foam obtained by heating, cooling in a mold, and then depressurizing.

According to the above-described method for producing an inorganic foam of the present invention, an inorganic foam having a stable and uniform cell structure containing a large amount of an inorganic filler can be produced efficiently and stably. In addition, the inorganic foam obtained by the present invention has no volume shrinkage and cracking during combustion, and has a small calorific value, making it lightweight, heat insulating, water resistant, sound absorbing, mechanical strength, non-flammable. Excellent foam.
Therefore, it can be suitably used not only as a building heat insulating material, but also as a member such as a wall, floor, roof, or duct of a building, a vehicle interior material, and a component material of various devices.

Hereinafter, an embodiment of the method for producing an inorganic foam according to the present invention will be described in detail.
The method for producing an inorganic foam of the present invention comprises kneading a vinyl chloride resin, a metal hydroxide, an inorganic fiber whisker, a flame retardant, and other inorganic fillers together with a foaming agent and an organic solvent in a kneader. Is prepared, heated and cooled in a pressurized mold, and then decompressed to produce an inorganic foam.

  The vinyl chloride resin used in the present invention may be a polymer having vinyl chloride as a main component of the monomer, and general vinyl chloride resins can be widely used. Further, the properties thereof are not particularly limited, and any of a paste resin by an emulsion polymerization method, a suspension resin by a suspension polymerization method, and a bulk polymerization resin by a bulk polymerization method can be used. A paste resin having a small particle size is preferred.

  Here, the vinyl chloride resin preferably has an average degree of polymerization of 1000 to 5000, and more preferably has an average degree of polymerization of 2000 to 4000. When the average degree of polymerization is less than 1000, the cell membrane is easily broken at the time of foaming, and the foam shrinks due to the escape of the foaming gas, which tends to increase the density of the foam. On the other hand, if it exceeds 5000, its production is difficult industrially, and even if possible, if such a resin having a large average degree of polymerization is used, the dispersion state of the kneaded product deteriorates and becomes uniform. It is difficult to obtain a foam having various bubbles. These vinyl chloride resins are not limited to the use of a single resin, and two or more kinds of resins having different polymerization degrees can be mixed and used.

  The average degree of polymerization of the vinyl chloride resin is measured based on JIS K 6720-2 (1999). Specifically, about 0.2 g of vinyl chloride resin dried at room temperature was weighed into a 50 ml volumetric flask, and about 40 ml of nitrobenzene was added thereto and heated to 100 ° C. After confirming that the sample was completely dissolved, the volumetric flask was cooled, and nitrobenzene was newly added to adjust the temperature to 30 ° C. to a total volume of 50 ml. This solution was used as a test solution, and an automatic viscometer (Ubbelohde viscometer) was obtained. ), While measuring the falling seconds of the test solution, measure the falling seconds of nitrobenzene by the same method, and determine the specific viscosity according to the same JIS. The specific viscosity is measured three times, and the average value is obtained. Subsequently, using the average value of the specific viscosity, the average degree of polymerization of the vinyl chloride resin is calculated from the formulas (1) and (2) described in the same JIS.

Examples of the metal hydroxide used in the present invention include aluminum hydroxide, magnesium hydroxide, calcium hydroxide, and tin hydroxide. Among these, aluminum hydroxide and magnesium hydroxide have a dehydration temperature. This is preferable because it is not so low that dehydration is started at the time of foam production, and is not so high that dehydration starts after combustion of the foam has considerably progressed. That is, aluminum hydroxide and magnesium hydroxide are dehydrated and decomposed when the foam is heated to 200 to 400 ° C., and the heat generated at that time reduces the amount of heat generated during combustion of the foam to increase the temperature of the foam. Can be suppressed.
The metal hydroxide whose weight is reduced by the dehydration reaction when heated is less effective as described above when added in a small amount, but conversely shrinks when the resulting foam is burned when added in a large amount. May increase. Therefore, the addition amount of the metal hydroxide is preferably 10 to 30 parts by weight, more preferably 15 to 25 parts by weight.

  In general, the smaller the average particle size of the metal hydroxide, the greater the effect on the combustion characteristics, and 0.5 to 40 μm is preferable, and 1 to 20 μm is more preferable. When the average particle size exceeds 40 μm, the shrinkage of the specimen during combustion increases, making it difficult to meet the performance evaluation test criteria. On the other hand, in the case of less than 0.5 μm, it is difficult to produce industrially and is difficult to obtain, and even if it can be produced, the production cost is very high and the production cost of the foam is high. Become.

  The average particle diameter of the metal hydroxide is measured using a laser diffraction particle size distribution analyzer SALD-7000 manufactured by Shimadzu Corporation. It is measured after taking a metal hydroxide in a 50 ml beaker, adding about 40 ml of pure water to which 0.1 wt% of hexametaphosphoric acid is added as a dispersant, and dispersing in an ultrasonic bath.

The inorganic fiber whisker used in the present invention is potassium titanate, aluminum borate, calcium silicate, basic magnesium sulfate, silicon carbide, silicon nitride, titanium oxide,
A whisker selected from alumina, glass fiber, calcium sulfate, calcium carbonate, zinc oxide, graphite, magnesia, magnesium borate, titanium diboride and the like. Since these inorganic fiber whiskers are uniformly dispersed in the foam, a three-dimensional network structure of the inorganic fiber whiskers is formed in the foam, and the shape of the foam is maintained even during combustion and cracks on the surface. Can be prevented.
Inorganic fiber whiskers in the present invention from the above, preventing shrinkage during combustion, from the viewpoint of the crack inhibiting effect is to use potassium titanate whiskers and / or basic magnesium sulfate whisker.

The addition amount of potassium titanate whisker and / or basic magnesium sulfate whisker is 1 to 25 parts by weight , and more preferably 3 to 15 parts by weight. When the amount added exceeds 25 parts by weight, the foaming efficiency may be reduced during foam production, or the closed cell ratio may be greatly reduced, and the resulting foam may have a high density. On the other hand, when the amount is less than 1 part by weight, there is a possibility that the effect of suppressing the volume shrinkage and cracking during combustion may not be exhibited.

In the present invention, the average fiber diameter of the inorganic fiber whiskers is preferably 5 μm or less, and more preferably 3 μm or less. The lower limit of the average fiber diameter is usually 0.1 μm. When the fiber diameter is 5 μm or less, the primary particle aspect ratio increases, so the effect of maintaining the foam shape due to the three-dimensional entanglement of the inorganic fiber whiskers increases. It is possible to effectively prevent the occurrence of cracks on the surface.
The average fiber length of the inorganic fiber whiskers is preferably 40 μm or less, and more preferably 30 μm or less. The lower limit of the average fiber length is usually 1 μm. When the average fiber length is 40 μm or less, the obtained foam can have a high closed cell ratio, and it is difficult to increase the density by shrinkage, and a high foaming efficiency corresponding to the amount of the chemical foaming agent can be achieved. .
The “average fiber length” refers to the arithmetic average value of the measured values of the fiber lengths of 50 inorganic fiber whiskers based on a 1000 × electron micrograph. The “average fiber diameter” refers to the arithmetic average value of the fiber diameters of 100 inorganic fiber whiskers. Here, the fiber diameter refers to the diameter when the fiber cross-sectional shape is circular, and when the fiber cross-sectional shape is non-circular, the diameter of a circle having the same area as the cross-sectional area is referred to as the fiber diameter. I reckon.

The flame retardant used in the present invention acts to make the vinyl chloride resin flame-retardant, and forms a strong carbonized film on the surface during combustion, and exhibits the effect of suppressing ignition of the foam and continuation of combustion. Any of those used conventionally can be used. Examples thereof include antimony compounds such as diantimony trioxide, diantimony tetroxide, and diantimony pentoxide, halogen-containing flame retardants, phosphorus-containing flame retardants, and nitrogen-containing flame retardants. Among them, antimony trioxide is preferably used because it has a high flame retardant effect.
The amount of flame retardant added is preferably 0.5 to 3 parts by weight. When the added amount exceeds 3 parts by weight, volume shrinkage tends to occur due to the weight reduction of the flame retardant itself during the combustion of the foam. At the same time, it becomes easy to increase the density of the foam during the production of the foam. On the other hand, when the amount is less than 0.5 part by weight, there is a possibility that the effect of suppressing ignition during combustion or continuation of combustion may not be exhibited.

  As the foaming agent used in the present invention, a so-called chemical foaming agent is used, and organic foaming agents azodicarbonamide, azobisisobutyronitrile, dinitrosopentamethylenetetramine, p-toluenesulfonyl human razide, p, Examples thereof include p-oxybis (benzenesulfonylhydrazide) and the like, and sodium bicarbonate, ammonium chloride, which are inorganic foaming agents. These foaming agents can be used alone or in combination of two or more. The foaming agent to be used is not particularly limited as long as it is selected from the above, but azodicarbonamide and azobisisobutyronitrile are preferably used because a desired foaming ratio can be easily obtained. The above foaming agent may be used in combination with a urea-based foaming aid, if necessary.

  The amount of the foaming agent added varies depending on the desired foaming ratio, the type of foaming agent used, the type of organic solvent and the amount thereof, but is usually 5 to 100 parts by weight with respect to 100 parts by weight of the vinyl chloride resin The amount is preferably 10 to 50 parts by weight, particularly preferably 20 to 50 parts by weight. If the amount of the foaming agent added is too small, only a product having a low expansion ratio can be obtained. If the amount of the foaming agent added is too large, the cell membrane may be destroyed at the time of foaming to cause continuous foaming.

  The organic solvent used in the present invention is generally used for the production of this kind of inorganic foams such as aliphatic hydrocarbons, aromatic hydrocarbons, alcohols, esters, ketones, cellosolves and the like. Things can be widely used. Examples of the aliphatic hydrocarbon include hexane and cyclohexane, examples of the aromatic hydrocarbon include toluene and xylene, and examples of the alcohol include methyl alcohol, ethyl alcohol, propyl alcohol, Examples include isopropyl alcohol, butyl alcohol, isobutyl alcohol, hexanol, 2-ethylhexanol, and examples of esters include methyl acetate, ethyl acetate, propyl acetate, butyl acetate, ethyl propionate, and butyl propionate. Examples of ketones include acetone, cyclohexanone, methyl ethyl ketone, diisobutyl ketone, methyl isobutyl ketone, and cyclopentanone. Examples of cellosolves include methyl cellosolve, ethyl Cellosolve and the like. These organic solvents can be used alone or in admixture of two or more.

Among the above organic solvents, toluene, ketones such as acetone, cyclohexanone, methyl ethyl ketone, or a mixed solvent thereof are preferably used in view of temperature conditions and kneading performance during kneader kneading.
The boiling point of the organic solvent is 0 to 250 ° C., preferably 10 to 210 ° C., more preferably 20 to 190 ° C. If the boiling point of the organic solvent is too low, the organic solvent may be volatilized during kneading in the kneader and sufficient kneading may not be obtained. On the other hand, if the boiling point is too high, it is difficult to volatilize and remove the organic solvent from the foam after foaming, which may lead to a decrease in mechanical properties of the foam.

In the present invention, other inorganic fillers can be added. This type of inorganic filler includes calcium, magnesium, aluminum, titanium, iron, zinc and other carbonates, sulfates, silicates, phosphates, borates, oxides, or powders of these hydrates. For example, calcium carbonate, magnesium carbonate, zinc oxide, gypsum, barium sulfate, aluminum silicate, magnesium silicate, calcium silicate, aluminum sulfate, magnesium sulfate, calcium sulfate, magnesium phosphate, glass flakes Hydrated aluminum, hydrated gypsum, silica, talc, clay, bentonite and the like.
These inorganic fillers are added in addition to the vinyl chloride resin, metal oxide, inorganic fiber whisker, and flame retardant, which are blending components in the present invention, and the amount added is 100 parts by weight with the addition of the inorganic filler. This is the amount.

  The particle size of the inorganic filler is an important factor in determining the absorption amount of the organic solvent, but has a preferable value depending on the type of the material. For example, in the case of talc, in order to improve the dispersibility, talc is preferably fine enough to pass 90% or more through a 150 mesh screen. In addition, calcium carbonate reacts with chlorine generated by the combustion of vinyl chloride resin to make it non-toxic, and improves the adhesion between the vinyl chloride resin and the organic solvent, so that it is fine enough to pass through a 70 mesh sieve. Among them, 20 to 80% by weight is preferably fine enough to pass through a 200 mesh screen.

  Other stabilizers such as dibasic phosphite, dibasic lead stearate, tribasic lead sulfate, zinc stearate, calcium stearate and titanium oxide for the purpose of preventing degradation of vinyl chloride resin A pigment such as an antistatic agent such as an alkyl sulfonate can be appropriately used as necessary.

Next, an example of the manufacturing method of the inorganic foam of this invention is demonstrated.
First, in the kneader, the above-mentioned vinyl chloride resin, metal oxide, inorganic fiber whisker, flame retardant and inorganic filler, foaming agent, if necessary, additives such as stabilizers are mixed in the above proportions, and the required amount Kneading while adding the organic solvent in several portions.
At this time, the temperature of the kneaded material in the kneader is preferably in the range of 0 to 50 ° C. so that the vinyl chloride resin does not gel and the foaming agent does not decompose and efficient kneading proceeds. .

Next, the obtained kneaded material is filled in the mold without any gap, and is pressurized and sealed with a hydraulically driven superheat press. The press pressure at this time is selected to be 130 kgf / cm ² or more. Next, the mold is heated to 100 to 170 ° C. under a press and held in that state for 5 to 40 minutes to promote gelation of the vinyl chloride resin and decomposition of the foaming agent.
As a result, the vinyl chloride resin is dissolved in the organic solvent, and fine particles such as inorganic fiber whiskers, metal hydroxides, and inorganic fillers are surrounded. At the same time, because the inside of the mold is in a high temperature and high pressure state, the decomposition gas of the foaming agent is uniformly diffused into the gelatinized vinyl chloride resin and inorganic fiber whiskers, metal hydroxides, inorganic fillers, etc. It becomes a state.

After the reaction is sufficiently performed, the mold is cooled to 0 to 80 ° C. using a cooling medium such as water, and then the pressure of the press is released to remove the product from the mold.
At this point, the product is 60-70% of the desired expansion ratio (primary expansion).
Next, the product is heated again to 90 to 120 ° C. in a warm air circulating apparatus such as an oven under normal pressure, and expanded to a target foaming ratio (secondary foaming).
Then, after expanding to the target expansion ratio, the temperature is lowered again to room temperature, and curing is performed to stabilize the shape.
Thereafter, the product is gradually heated to remove the organic solvent, and a product as an inorganic foam is obtained.

Since the inorganic foam obtained by the production method according to the present invention is formed by closed cells mainly composed of an inorganic filler, it has lightness, heat insulation, sound absorption, and mechanical strength. It also has dimensional stability and nonflammability.
Further, in the inorganic foam obtained by the production method according to the present invention, a predetermined amount of inorganic fiber whiskers are added and dispersed, so that a three-dimensional network structure of inorganic fiber whiskers is formed in the foam. Even during combustion, the shape of the foam is maintained, and the occurrence of cracks on the surface can be prevented.
In addition, the inorganic foam obtained by the production method according to the present invention using metal hydroxide, particularly aluminum hydroxide or magnesium hydroxide, can be obtained when the foam is heated to 200 to 400 ° C. The hydroxide is dehydrated and decomposed, and the heat generated at that time can reduce the amount of heat generated during the combustion of the foam, thereby suppressing an increase in the temperature of the foam, and is further excellent in incombustibility.

Further, in the present invention, it contains a flame retardant and forms a strong carbonized film on the surface of the foam during combustion, thereby exhibiting the effect of suppressing the ignition of the foam and the continuation of combustion, but with higher flame retardancy in terms of the things, it is preferable that the apparent density of the foam is ^{60kg / m 3 ~150kg / m 3} , in addition, as the content of the vinyl chloride resin per foam 1 cm ³ not exceeding 0.05g It is preferable to mix a vinyl chloride resin, and the thickness of the foam is preferably at least 10 mm, and more preferably 12 mm to 100 mm.

  The inorganic foam obtained by the production method according to the present invention will pass the exothermic test by a cone calorimeter which is a performance evaluation test as a non-combustible material shown in Building Standard Law Article 2 No. 9. Of course, it can be suitably used as a building heat insulating material, a member such as a wall, floor, roof, or duct of a building, a vehicle interior material, and a component of various devices.

  Hereinafter, although described with the Example of the manufacturing method of the inorganic type foam of this invention, and a comparative example, this invention is not limited to the following Example at all.

Examples 1-22

[material]
・ Vinyl chloride resin:
Vinyl chloride resin A (manufactured by Vitec Co., Ltd., product name: P470, polymerization degree: 3700)
Vinyl chloride resin B (manufactured by Vitec Co., Ltd., product name: P480, polymerization degree: 2700)
Vinyl chloride resin C (manufactured by Kaneka Corporation, product name: PSH-31, degree of polymerization: 1700)
Vinyl chloride resin D (manufactured by Tosoh Corporation, product name: R960, polymerization degree: 4500)
・ Metal hydroxide:
Aluminum hydroxide A (manufactured by Arco Chemicals, product name: UFH-20,
(Average particle size: 2 μm)
Aluminum hydroxide B (manufactured by Arco Chemicals, product name: B-325,
(Average particle size: 27 μm)
Magnesium hydroxide (Kyowa Chemical Industry Co., Ltd., product name: Kisuma 5A, average particle size:
1μm)
・ Inorganic fiber whiskers:
Potassium titanate (Otsuka Chemical Co., Ltd., product name: TISMO-D, average fiber diameter:
0.5μm, average fiber length: 15μm)
Basic magnesium sulfate (manufactured by Ube Materials Co., Ltd., product name: Moss Heidi, average fiber diameter: 0.5 μm, average fiber length: 20 μm)
·Flame retardants:
Antimony trioxide (Suzuhiro Chemical Co., Ltd., product name: AT3)
・ Calcium carbonate:
70 mesh pass: 200 mesh pass weight ratio 3: 2 mix / talc:
600 mesh pass foaming agent:
Azobisisobutyronitrile (Otsuka Chemical Co., Ltd., product name: AIBN)
Azodicarbonamide (Product name: Uniform AZM-3, manufactured by Otsuka Chemical Co., Ltd.)
·Organic solvent:
toluene

[Production of foam]
First, the above raw materials were blended so as to have the blending amounts shown in Tables 1 to 3, and kneaded to obtain a kneaded product.
For kneading, all the raw materials except for toluene are put into a kneader, kneaded for 15 minutes, then toluene is added in four portions, and kneaded for 15 minutes every time one toluene is added, for a total of 60 minutes. Went. Further, during kneading, the temperature of the kneaded product was adjusted to 50 ° C.
Next, the obtained kneaded material was filled in a 120 mm × 120 mm, 25 mm deep mold without any gap, covered with a top, and pressurized with a pressure press at a pressure of 150 kgf / cm ² . Thereafter, the mold is heated to 150 ° C. and held for 20 minutes to gel the vinyl chloride resin in the kneaded product and decompose the foaming agent, then immediately cooled to 50 ° C. and held for 30 minutes, Opened to obtain a plate-like foam.
Subsequently, the obtained foam was subjected to secondary foaming by storing in an oven at 80 ° C. for 2 hours. Then, after leaving it to stand in a room at 20 ° C. for 12 hours and cooling (curing), it was left again in an oven at 80 ° C. for 24 hours to volatilize the remaining toluene. Thereafter, the foam was allowed to stand for 12 hours in a room at 20 ° C. and cooled (cured), and then the performance of the foam described later was measured.

[Performance of foam]
With respect to the produced foam, its apparent density, closed cell ratio, thermal conductivity, total calorific value, maximum heat generation rate, shrinkage / crack were measured according to the following methods.

・ Apparent density:
A sample having a size of 200 mm × 200 mm × 25 mm was cut out from the foam, and its volume and weight were measured and calculated.

・ Closed cell ratio:
A cut sample without a molded skin cut to a size of 25 mm × 25 mm × 20 mm from the foam is accommodated in a cup, and an air comparison type hydrometer made by Toshiba Beckman Co., Ltd. according to the procedure C of ASTM-D2856-70 Using the true volume Vx of the foam (cut sample) measured using type 930, the closed cell ratio S (%) was calculated by the following formula, and the average value of the three was obtained.

(Equation 1)
S (%) = (Vx−W / ρ) × 100 / (VA−W / ρ)
Vx: The true volume (cm ³ ) of the cut sample measured by the above method, which corresponds to the sum of the volume of the resin constituting the foam cut sample and the total volume of bubbles in the closed cell portion in the cut sample To do.
VA: apparent volume (cm ³ ) of the cut sample calculated from the outer dimensions of the cut sample used for the measurement.
W: Total weight (g) of cut sample used for measurement.
ρ: Density (g / cm ³ ) of the filler-containing resin composition constituting the foam.

·Thermal conductivity:
A test piece having a length of 200 mm, a width of 2000 mm, and a thickness of 25 mm cut out from the foam after 4 weeks from the manufacture was described in accordance with JIS A9511-4.7 (1995). Measurement was performed based on a flat plate heat flow meter method (two heat flow meter method, average temperature 20 ° C.) described in JIS A1412 (1994) using “Auto Λ HC-73”.

・ Total heat generation and maximum heat generation rate:
The exothermic test was conducted with a cone calorimeter based on ISO 5660 part 1, and the total calorific value 10 minutes and 20 minutes after the start of ignition and the maximum heat generation rate therebetween were measured.
In addition, the test body in this test used what was cut out to the size of 99 mm x 99 mm square from the foam (The thickness of the test body was made into the thickness of the obtained foam).
The standard of non-combustibility in the corn calorimeter is as follows (the quasi-incombustible standard is in parentheses).
(1) The total calorific value for 20 minutes (10 minutes) after the start of heating is 8 MJ / m ² or less.
(2) The maximum heat generation rate should not exceed 200 kW / m ² for 20 minutes (10 minutes) after the start of heating for 10 seconds or more.
(3) There should be no cracks or holes reaching the back side, which is harmful to fire prevention, for 20 minutes (10 minutes) after the start of heating.
The maximum heat generation rate was evaluated according to the following criteria in the exothermic test using the corn calorimeter (the quasi-incombustibility standard in parentheses).
○: 20 minutes (10 minutes) after the start of heating, the maximum heat generation rate continued for 10 seconds or more and did not exceed 200 kW / m ² .
X: 20 minutes (10 minutes) after the start of heating, the maximum heat generation rate continued for 10 seconds or more and exceeded 200 kW / m ² .

·crack:
The specimens after the exothermic test by the corn calorimeter (10 minutes after the start of heating for the evaluation of quasi-incombustibility and 20 minutes after the start of heating for the evaluation of nonflammability) were observed and evaluated according to the following criteria.
○: No crack or hole reaching from the front surface to the back surface of the specimen.
X: Cracks or holes reaching from the front surface to the back surface of the specimen are observed.

・ Shrinkage:
In the exothermicity test using the cone calorimeter, the test specimen is wrapped with aluminum foil on the side and back and placed in a holding frame, and the back is filled with inorganic fibers before being pushed into the specimen holder. . In the holding frame, a part of the end portion of the upper surface of the test piece (the surface facing the inside of the 99 mm × 99 mm surface (radiation heat exposure surface)) is covered with the frame body. Specifically, the frame body covers from each side of a 99 mm square that forms the upper surface of the test body to a portion that enters 2.5 mm inside. As a result, in the test, a 94 mm square portion on the upper surface of the test body becomes a radiant heat exposed portion. The shrinkage referred to here is the frame body after the exothermic test by the cone calorimeter (10 minutes after the start of heating for the evaluation of semi-incombustibility and 20 minutes after the start of heating for the evaluation of nonflammability) with the frame installed. The test specimens were observed from directly above at the respective positions around the entire circumference of the specimen and evaluated according to the following criteria.
(Double-circle): The aluminum foil located in the test body back surface is not recognized.
○: As a result of the shrinkage of the specimen, a gap is formed between the frame body and the specimen, and the aluminum foil located on the back of the specimen is observed through the gap, but the area of the largest aluminum foil to be observed is Less than 5 mm ² .
Δ: As a result of the shrinkage of the test body, a gap is formed between the frame body and the test body, and an aluminum foil located on the back surface of the test body is observed through the gap, but the area of the largest aluminum foil to be observed is It is 5 mm ² or more and less than 50 mm ² .
×: As a result of the shrinkage of the test body, a gap is formed between the frame body and the test body, and the aluminum foil located on the back surface of the test body is observed through the gap, but the area of the largest aluminum foil to be observed is It is 50 mm ² or more.

  Tables 1 to 3 show the measurement results of the performance tests described above.

Comparative Example 1-11
Except that the raw materials shown in Table 4 were blended, a foam was produced in the same manner as in the above examples, and the obtained foam was subjected to the same performance test as above. The measurement results are shown in Table 4.

  Examples 1 to 18 are examples in which potassium titanate whiskers were used, but the obtained foams had a small total calorific value and maximum exothermic rate at the time of the exothermic test, and the shrinkage of the test specimen was extremely low. In addition, the generation of cracks or holes penetrating on the opposite surface side was not observed, and the dimensional stability was excellent.

Comparative Example 11 is an example using a metal hydroxide (aluminum hydroxide) having a slightly larger average particle diameter than Examples 1-9 and Examples 11-14, but the total calorific value during the exothermic test and The maximum heat generation rate was small, and no cracks or holes penetrating the opposite surface side were observed in the specimen, but the shrinkage was somewhat large due to the use of aluminum hydroxide having a large average particle diameter . From this result, it is preferable that the average particle diameter of the metal hydroxide is not too large.

  Example 11 shows an example using a vinyl chloride resin having a polymerization degree smaller than that of Example 5 (below 2000). Example 12 shows an example in which a vinyl chloride resin having a degree of polymerization larger than that of Example 5 (exceeding 4000) is used. In any of the examples, it can be seen that the foaming efficiency is slightly lower than in Example 5, and the density is higher than that of the foam obtained in Example 5. From this result, it can be said that the degree of polymerization of the vinyl chloride resin used is particularly preferably 2000 to 4000 in order to improve the foaming efficiency.

  In addition, Examples 19 to 21 are examples using basic magnesium sulfate whiskers, but the obtained foam has a small total calorific value and maximum exothermic rate during the exothermic test. The shrinkage was very small, and cracks or holes penetrating on the opposite surface side were not observed, and the dimensional stability was excellent.

Examples 16 to 18 are examples in which the thickness of the exothermic test specimen was 50 mm. Since the absolute amount of vinyl chloride resin in the specimen is large due to the thick thickness, the total calorific value after 20 minutes exceeded 8 MJ / m ² and did not satisfy the nonflammability standard, but the total after 10 minutes The calorific value is within 8 MJ / m ² and satisfies the quasi-incombustibility standard. The shrinkage after the test is very small, and there are no cracks or holes penetrating on the opposite side, and the dimensional stability is excellent. It was a thing. Moreover, also in Example 22 using a basic magnesium sulfate whisker, since the thickness of the exothermic test specimen was 50 mm, the same tendency as in Examples 16 to 18 was exhibited.

  On the other hand, Comparative Example 1 is contrasted with Example 1, but since the blending amount of the vinyl chloride resin was too small, it could not withstand the foaming pressure, and bubble formation was observed at all. There wasn't. Therefore, the exothermic test of the foam was not performed.

Comparative Example 2 is in contrast to Example 1, but because the amount of vinyl chloride resin was too large, the total calorific value measured by the exothermic test was 8 MJ / m ² or more. Further, no cracks were observed after the test, but the degree of shrinkage was large. In any case, neither the incombustibility standard nor the quasi-incombustibility standard was satisfied.

Although the comparative example 3 is contrasted with Example 5, since there were few compounding quantities of a metal hydroxide (aluminum hydroxide), the measurement result of the total calorific value by an exothermic test became 8 MJ / m < ² > or more, In any case, neither the incombustibility standard nor the quasi-incombustibility standard was satisfied.

Comparative Example 4 is contrasted with Example 17, but because the amount of metal hydroxide (aluminum hydroxide) was small, the total calorific value measured by the exothermic test was 8 MJ / m ² or more. However, neither the incombustibility nor the quasi-incombustibility standards were satisfied.

Comparative Example 5 is contrasted with Example 17, but since no flame retardant (antimony trioxide) was added, the total calorific value measured by the exothermic test was 8 MJ / m ² or more. However, neither the incombustible standard nor the quasi-incombustible standard was satisfied.

Comparative Example 6 is contrasted with Example 5, but because the amount of metal hydroxide (aluminum hydroxide) was large, the total calorific value was 8 MJ / m ² or less. The degree of shrinkage was large, and in any case, neither the incombustibility nor the quasi-incombustibility standards were satisfied.

  Comparative Example 7 is contrasted with Example 5, but since inorganic fiber whiskers (potassium titanate) were not blended, the degree of cracking and shrinkage after the exothermic test was large, and in any case, a nonflammable standard The quasi-incombustible standard was not satisfied.

  Comparative Example 8 is contrasted with Example 5, but because the amount of inorganic fiber whiskers (potassium titanate) was large, the foaming efficiency with respect to the added foaming agent was reduced, and a low-density foam was obtained. I could not. No further evaluation was performed.

  Comparative Example 9 is contrasted with Example 5, but because the blending amount of the flame retardant (antimony trioxide) was large, the foaming efficiency with respect to the added foaming agent was reduced, and the resulting foam had a high density. Turned into. In addition, the shrinkage after the exothermic test was large, and in any case, neither the incombustibility nor the quasi-incombustibility was satisfied.

  Comparative Example 10 is contrasted with Example 5, but since no flame retardant (antimony trioxide) was blended, the effect of reducing the total calorific value by the flame retardant disappeared. The quasi-incombustible standard was not satisfied.

Claims (1)

(A) 5 to 30 parts by weight of vinyl chloride resin, (b) 10 to 30 parts by weight of aluminum hydroxide or magnesium hydroxide having an average particle size of 0.5 to 20 μm , (c) fiber length of 1 to 40 μm 1 to 25 parts by weight of potassium titanate whisker and / or basic magnesium sulfate whisker having a fiber diameter of 0.1 μm to 5 μm , (d) 0.5 to 3 parts by weight of antimony trioxide as a flame retardant , ( e) Other inorganic fillers (total of (a) to (e) is 100 parts by weight), a foaming agent, and an organic solvent are kneaded, and the kneaded product is heated and cooled in a pressurized mold. Then, the manufacturing method of the inorganic type foam obtained by decompressing.