KR102024347B1 - Method for producing flame―retardant board - Google Patents

Abstract

The present invention relates to a method for manufacturing a flame-retardant board, which comprises: a foaming step of foaming a foamed styrene raw material to produce foam particles; a drying step of drying the foamed particles after the foaming step; an adhesive applying step of applying a foaming first adhesive to an outer surface of the foam particles to provide an adhesive layer after the drying step; a flame retardant applying step of applying a flame retardant to provide a flame-retardant layer after the adhesive applying step; an aging step of aging a flame-retardant bead applied with the flame retardant; a molding step of forming a board by molding the flame-retardant bead after the aging step; and a board drying step of drying the board molded in the molding step. In the flame retardant applying step, temperatures of an external space where apparatuses for manufacturing a flame-retardant bead are installed, are controlled to reduce an internal temperature gradient thereof.

Description

Method for producing flame retardant board {Method for producing flame―retardant board}

The present invention relates to a method of manufacturing a flame retardant board, and more particularly, to a method of manufacturing a board having a semi-combustible performance by preventing peeling of a flame retardant layer, which has been peeled off due to lack of conventional bonding strength, with securing adhesion.

Flame retardant board is divided into non-combustible (class 1 flame retardant), quasi-non-flammable (class 2 flame retardant), flame retardant (class 3 flame retardant). Flame retardant board is usually manufactured by coating flame retardant on foam particles and forming coated flame retardant bead It is becoming.

The flame retardancy of the flame retardant board is determined by the amount of flame retardant. When a large amount of flame retardant is used to increase the flame retardancy, problems of weakening of the fusion force between the flame retardant particles and weakening of the flame retardant, and a problem of deterioration of thermal insulation due to high thermal conductivity do. As a result, when the sandwich panel is manufactured from the flame retardant board, the metal plate and the flame retardant board may be separated from each other.

In fact, many of the flame retardant boards on the market do not pass the standard test, so there is a demand for the development of technology related to the flame retardant board that can actually protect people and property.

Republic of Korea Patent Publication No. 2016-0071080

One aspect of the present invention is to specify the structure and composition of the adhesive layer and the flame retardant layer to prevent the peeling of the flame retardant layer and to provide a flame retardant bead is enhanced adhesion.

In addition, one aspect of the present invention is to provide a flame retardant bead that can increase the foam size of the foam particles to increase the particle size when forming the heat insulating material to improve the adhesion and provide a high density.

In addition, one aspect of the present invention is to provide a board having improved compressive strength and flexural fatigue strength by including the flame retardant bead with enhanced fusion.

One aspect of the present invention is to provide an apparatus for producing a flame retardant bead that can provide a flame retardant layer suitable for interlayer fusion with improved flame retardant performance.

One aspect of the present invention is to provide a device for strengthening the welding force of the flame retardant beads that are improved in flame retardance to the extent that no perforation occurs to produce a board.

One aspect of the present invention is to provide a method for efficiently manufacturing a board with enhanced bead between beads.

One aspect of the present invention is to provide a method of manufacturing a board having a semi-combustible performance by preventing the peeling of the flame-retardant layer that was peeled off due to lack of fusion strength with securing fusion.

One aspect of the present invention relates to a manufacturing apparatus and a manufacturing method of a sandwich panel, and more particularly, to a sandwich panel manufacturing apparatus and manufacturing using a board or a semi-combustible board molded into a panel with improved adhesion, flame retardancy and flame retardancy It is an object to provide a method.

The above and other objects of the present invention can be achieved by the present invention described below.

Method for manufacturing a flame retardant board according to an aspect of the present invention,

Foaming step of producing foamed particles by foaming the foamed styrene raw material;

A drying step of drying the foamed particles after the foaming step;

An adhesive coating step of applying an expandable first adhesive to an outer surface of the foam particles after the drying step to provide an adhesive layer;

A flame retardant coating step of providing a flame retardant layer by applying a flame retardant after the adhesive coating step;

A maturation step of maturing the flame retardant beads to which the flame retardant is applied;

A molding step of forming the board by molding the flame retardant beads after the aging step; And

And a board drying step of drying the molded board in the forming step,

In order to reduce the internal temperature gradient of the devices in which the flame retardant beads are manufactured in the flame retardant coating step, it is characterized in that to control the temperature of the external space in which the device is installed.

In addition, the adhesive coating step may be applied to the outer surface of the foam particles after the drying step 1 to 10 parts by weight based on 100 parts by weight of the foam particles.

In addition, the flame retardant coating step, it is preferable to apply a mixed liquid of the flame retardant and the second adhesive agent.

At this time, the flame retardant coating step may be applied to the mixture of the second adhesive and the flame retardant 100 to 250 parts by weight based on 100 parts by weight of the foam particles.

In addition, the expanded styrene raw material may be a foaming ratio of 70 to 150 times.

At this time, it is preferable that the said 1st adhesive agent and the 2nd adhesive agent are foam adhesives.

In addition, the first adhesive and the second adhesive may be to foam in the flame retardant coating step, the aging step, the molding step and the board drying step.

In addition, the drying step may be performed by adjusting the temperature gradient between the central temperature and the upper temperature inside the main body by blocking the upper outside air of the main body to be dried.

At this time, the drying step is preferably carried out while blowing hot air from the lower part of the main body to be dried and heating the bottom of the main body.

In addition, the flame retardant coating step

Mixing the flame retardant raw materials;

A coating step of coating the flame retardant mixed in the mixing step by stirring for 100 to 300 seconds at a temperature exceeding 40 ° C. or less than 60 ° C .;

A post-coating drying step of drying by stirring for 100 to 500 seconds at a temperature below 50 ° C. after the coating step; And a transfer step of transferring while drying over 100 to 300 seconds at a temperature of less than 50 ℃ after the drying step after the coating.

In addition, the aging step may be to mature for 2 to 5 hours at 40 ℃.

In addition, the molding step may be carried out by vacuum cooling for 40 to 50 seconds after the first step of 10 to 20 seconds and the two-step steam treatment of 1 to 5 seconds under the steam pressure of 1 ~ 5kg / cm.

At this time, the molded board is preferably aged for at least 24 hours at 20 ℃ or more after drying for 1 to 3 hours at 40 ~ 50 ℃.

In addition, when the average diameter after the coating step of the flame retardant bead is s1, and the average diameter after the board drying step of the flame retardant bead is s2, s2 ≥ s1 + s1 × 0.005.

According to another aspect of the present invention, there is provided a flame retardant board manufactured by the method described above.

According to still another aspect of the present invention, there is provided a sandwich panel in which metal plates are adhered to both surfaces of a flame retardant board manufactured by the above-described method.

As described above, the flame retardant bead according to one aspect of the present invention can prevent the flame retardant layer from being peeled off by improving the bonding force between the foamed particles and the flame retardant layer. In addition, there is an effect to strengthen the adhesion between the foam particles.

In addition, by increasing the degree of foaming of the foam particles, the particle size is increased according to the strengthening of the foam, and as a result, the force that the foam particles collide with each other may be increased to provide a high density.

In addition, the apparatus for producing a flame retardant bead according to an aspect of the present invention may improve the change in the foaming state of the foamed particles according to the temperature of the outside air, thereby manufacturing a flame retardant board having improved flame retardancy and fusion. At this time, the flame resistance is improved to the extent that no perforation occurs during the fire test.

In addition, the method for manufacturing a flame retardant board according to an aspect of the present invention may improve the change in the foaming state of the foamed particles according to the temperature of the outside air, thereby manufacturing a flame retardant board having improved flame retardancy and fusion.

 The method for manufacturing a flame retardant board according to an aspect of the present invention has an effect of enhancing adhesion between the flame retardant beads and adhesion between the foam particles and the flame retardant layer.

The apparatus for manufacturing a flame retardant board according to an aspect of the present invention is provided with a temperature gradient control means in a space in which a coating machine is additionally required for foaming so that coating and foaming can be efficiently realized in the coating machine.

According to one aspect of the invention the manufacturing apparatus of the sandwich panel has the effect of improving the bonding force between the metal plate and the board. In particular, it is possible to prevent the separation between the metal plate and the board caused by the change in the thermal expansion coefficient of the metal plate.

Even if the effects are not expressly stated herein, the effects described in the following specification and the tentative effects expected by the technical features of the present invention are treated as described in the specification of the present invention.

1 is a schematic cross-sectional view of a flame retardant bead according to an embodiment of the present invention.
2 is a view schematically showing an apparatus for manufacturing a flame retardant bead according to an embodiment of the present invention.
3 is a conceptual diagram of a coating machine according to an embodiment of the present invention.
Figure 4 is a photo (a) showing that the beads are broken when broken as a result of strong fusion of the flame retardant beads in the board formed in accordance with the second embodiment of the present invention is broken as a result of weak fusion of the flame retardant beads in the market on the market The photograph (b) shows that the beads are located on either side of the cut surface while maintaining the spherical shape.
Figure 5 is a photograph showing the results of the bending fatigue strength in the board formed in accordance with the second embodiment of the present invention as a result of being bent but not cut even when folded to 180 °.
Figure 6 is a photograph (a) showing the results of the quasi-non-flammable experiment in the board molded in accordance with Example 2 of the present invention and a photograph (b) showing the results of the quasi-non-flammable experiment in the quasi-non-flame board on the market.
FIG. 7 is a photograph of a flame retardant bead remaining on a metal plate when a sandwich panel is molded according to an embodiment of the present invention, and a picture of a flame retardant bead remaining on a metal plate when a sandwich panel is commercially available. to be.
8 is a schematic view of an apparatus for manufacturing a sandwich panel according to Embodiment 4 of the present invention.

Hereinafter, with reference to the accompanying drawings, a flame retardant bead and a semi-non-combustible insulation according to an embodiment of the present invention, a manufacturing method and a manufacturing apparatus thereof will be described in detail. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.

Prior to describing the present invention in detail below, it is understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the invention, which is limited only by the scope of the appended claims. shall. All technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art unless otherwise indicated.

Throughout this specification and claims, unless otherwise indicated, the termcomprise, constitutes, and configure means to include the referenced article, step, or group of articles, and step, and any other article It is not intended to exclude a stage or group of things or groups of stages.

On the other hand, various embodiments of the present invention can be combined with any other embodiment unless clearly indicated to the contrary. Any feature indicated as particularly preferred or advantageous may be combined with any other feature and features indicated as preferred or advantageous.

In the drawings, the width, length, thickness, etc. of the components may be exaggerated for convenience. When described in the drawing as a whole, at the point of view of an observer, when one component is said to be "on / below" or "on / under" another component, this is not only when other components are "on or directly below". This includes the case where there is another component in the middle.

The present inventors have completed the present invention by identifying a technique for enhancing the adhesion and flame retardancy of the beads constituting the board.

Specifically, the adhesion of the beads constituting the board in the present invention is enhanced for the following reasons.

First, the structure and composition of the adhesive layer and the flame retardant layer may be mentioned. In the present invention, the adhesive layer serves to bond the foam particles and the flame retardant layer. The reason for providing the adhesive layer as described above is to improve the bonding strength when bonding the foam particles and the flame retardant layer by forming the adhesive layer evenly over the entire surface of the foam particles. Therefore, it is important that the adhesive layer is coated at least 95%, preferably at least 98% of the entire surface of the foam particles. In this case, since the flame retardant layer has a relatively low adhesive strength compared to the adhesive layer, when the adhesive layer is not provided, the flame retardant layer may be peeled off and the flame retardant effect may be reduced, thereby preventing such peeling from the flame retardant bead manufacturing step.

In addition, to help prevent such peeling, the flame retardant layer preferably has a function of the flame retardant and at the same time preferably further includes a urethane foam adhesive. By the adhesive included additionally, it is possible to reinforce the effect of strengthening the adhesion between the beads and the flame retardancy as well as peeling the flame retardant layer.

When the flame-retardant board of the present invention is broken (in case of breaking the board rather than cutting with a tool), it can be seen that the flame-retardant beads are joined by the enhanced welding force. On the other hand, conventionally, since the fusion strength between the flame retardant beads is weak, it can be confirmed that the flame retardant beads are not broken and are pulled while maintaining the bead shape on either of the fracture surfaces.

Second, it is due to increasing the degree of foaming of the foam particles. As foaming of the foam particles is enhanced, the particle size is increased, and the force that the foam particles collide with each other increases to achieve a high density to form a board tightly with each other.

Thus, in the embodiment of the present invention, the foaming, aging, coating, molding, drying process of the foam particles to enhance the overall foamability. At this time, in order to maximize the adhesion and flame retardancy, the size of the foam particles should be uniformly made. To this end, various aspects of the present invention include various means for preventing the size of the expanded particles from changing in accordance with the temperature gradient during the process in order to maintain a constant size of the expanded particles.

In addition, the foaming may be further increased due to the effect of the foamed adhesive contained in the adhesive layer and the flame retardant layer as well as the degree of foaming of the foam particles themselves. That is, after coating, the particle size before molding (also referred to as s1 hereinafter) increases to the grain size after board manufacturing (hereinafter referred to as s2). At this time, it is preferable that s1 and s2 have a relationship of s2 ≧ s1 + s1 × 0.005.

<First side>

A first aspect of the invention relates to a flame retardant bead and a board on which a flame retardant bead is molded. The flame retardant bead relates to a flame retardant bead having a structure formed by coating a flame retardant through an adhesive layer on the outer surface of the foam particles formed by foaming the foamed styrene raw material.

The flame-retardant beads are made to foam the foamed styrene raw material is dried under an appropriate temperature gradient to expand the expanded particles of less flat form to make a more tangled form. The method of drying under this temperature gradient will be described in detail in the section of the manufacturing apparatus of the second aspect described later.

The expanded styrene raw material has an average diameter of 0.5 to 1.5mm, and having a maximum foaming ratio of 70 to 150 times, or 75 to 110 times, is preferably used in the present invention, but is not limited thereto.

Such foam particles correspond to the innermost core indicated by reference numeral 11 with reference to FIG. 1 schematically showing a cross-sectional view of a spherical flame retardant bead as an embodiment of the flame retardant bead.

At this time, the foam particles 11 may be various, such as spherical shape, pillar shape or rugby ball shape, but preferably having a spherical shape is preferable when considering the processability of the molding to be described later.

Since the foaming particle 11 expands and expands the foaming agent to the softened raw material by applying heat, the one-time foaming furnace cannot obtain foamed particles in a sufficiently tangled state, and is dried by adjusting the temperature gradient after foaming. The unrolled foam particles may be unwrapped to form a tangle-like shape as shown in FIG. 1.

Flame retardant beads according to an embodiment of the present invention can be provided using the above-described foam particles. That is, an adhesive layer (corresponding to reference numeral 12 in FIG. 1) having a thin film thickness t2 by coating a first adhesive on an outer surface of the foam particles; And a flame retardant layer (corresponding to reference numeral 13 of FIG. 1) including the second adhesive and a flame retardant on the adhesive layer 12 and coated with a thickness t3 thicker than t2.

Herein, when the radius of the expanded particles is t1, the thickness ratios of the layers correspond to a ratio of t1 and t2 + t3, for example, 1: 0.0001 to 1: 0.2, 1: 0.001 to 1: 0.2, 1: 0.01 to 1: 0.2, 1: 0.0001 and 1: 0.02, or 1: 0.0001 and 1: 0.002. Within this range, it is possible to provide enhanced adhesion and flame retardancy and prevention of peeling of the flame retardant layer.

The first adhesive and the second adhesive may use the same or different urethane-based adhesives, and in particular, it is more preferable to use a urethane foam adhesive to provide additional foaming of the foam particles when sufficient heat is given. Examples of such urethane foam adhesives may include monomeric diisocyanates, and specific examples include methylene diphenyl diisocyanate (MDI) materials.

The methylenediphenyl diisocyanate is a material obtained by treating phosgene (COCl 2) with diphenylmethanediamine produced by condensation of aniline and formaldehyde, and considering the storage properties and ease of use, the polymeric MDI (MDI) and the modi MDI ( Various types of MDIs, such as modified MDI), monomeric MDI, and pure MDI (prepolymer), are prepared. In the present invention, all of these various types of MDI may be used, and the form is not particularly limited.

The methylene diphenyl diisocyanate is relatively small and easily dispersed compared to other hydrophobic resin components, and isocyanate group (-NCO) included in the molecular structure reacts with a compound having active hydrogen to generate a urethane bond and urea bond. It is possible to remove moisture in the steam and increase the crosslinking density of the hydrophobic resin to improve the adhesiveness, thereby improving the mechanical properties of the flame-retardant expanded styrene particles.

Thermally expandable microspheres may be included in the urethane foam adhesive in an amount of 10 wt% or less based on the adhesive content. The thermally expandable microspheres are compatible with the urethane foam adhesive and correspond to materials suitable for carrying out further foaming in the coating step described below, in particular the molding step.

These thermally expandable microspheres have the form of a capsule having a hollow and a shell and contain a liquid in the hollow having a boiling point below the softening temperature of the shell for foaming. Such liquid may be a hydrocarbon, and more preferably a hydrocarbon having a boiling point of less than 60 ° C. at atmospheric pressure. In one example, the preferred foam liquid therein is isobutane.

On the other hand, the acryl-based copolymer constitutes a shell, which is powdery at room temperature, but expands the capsule by vaporization of the liquefied hydrocarbon in the hollow at high temperature and may be applied as a blowing agent. On the other hand, unlike conventional chemical blowing agents have the advantage that the gas is not exposed to the surface.

Such thermally expandable microspheres are commercially available from Akzo Nobel under the trade name Expancel 980 DU 120.

That is, the adhesive layer in the present invention serves to bond the foam particles and the flame retardant layer. Thus, by providing the adhesive layer separately, the adhesive layer is formed evenly over the entire surface of the foam particles, thereby improving the bonding strength when the foam particles and the flame retardant layer are bonded. In this case, since the flame retardant layer has a relatively low adhesive strength compared to the adhesive layer, when the adhesive layer is not provided, the flame retardant layer may be peeled off and the flame retardant effect may be reduced, thereby preventing such peeling from the flame retardant bead manufacturing step.

The flame retardant includes, for example, a flame retardant filler including at least one selected from the group consisting of expanded graphite, aluminum powder, Al (OH) 3, Mg (OH), Al 2 O 3, iron, zinc, copper, and alloys thereof.

The flame retardant is preferably used in the liquid form using water or an organic solvent when considering aspects such as workability, uniformity of the coating film.

In addition, the flame retardant preferably includes a thermoplastic resin such as a vinyl acetate resin, a polyvinyl acetate resin (PVA), an acrylic resin, and an ethylene vinyl acetate resin (EVA) serving as a binder.

The expanded graphite is preferably included in the range of 20 to 40 parts by weight with respect to 100 parts by weight of the thermoplastic resin, and can suppress cracking and the like, with a sufficient flame retardant effect.

The expanded graphite used in the present invention is a material that imparts flame retardancy, and water and oxidized compounds generated by heat generate gas, and as a result, scaly graphite expands to form a stable layer in heat or chemicals. Therefore, the flame retardant effect is exhibited by the solid phase char method.

Since the expanded graphite is a flame-retardant forming a halogen-free solid state, it is possible to suppress the low smokeability is environmentally preferable, and it is also possible to simultaneously solve the separation problem and the flame retardancy problem by the main problem of the inorganic material.

Expanded graphite used in the present invention is an epoxy-containing silane having a weight average molecular weight of 100 ~ 400 g / mol to suppress aggregation between each other; Phenyl group-containing silanes; Vinyl group-containing silanes such as vinyltrichlorosilane and vinyltrimethoxysilane; N-2 (aminoethyl) -3-aminopropylmethyldimethoxysilane, N-2 (aminoethyl) 3-aminopropyltrimethoxysilane, N-2 (aminoethyl) 3-aminopropyltriethoxysilane, 3 -Aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilane-N- (1,3-dimethylbutylidene) propylamine, N-phenyl-3-aminopropyltrimethoxy Amine group-containing silanes such as silanes; And expanded graphite coated with a silane compound selected from the group consisting of a mixture thereof. The amount of the silane compound may be included in the range of 0.01 to 20 parts by weight based on 100 parts by weight of expanded graphite, but is not limited thereto.

The expanded graphite is preferably used from 80 to 240 mesh of fine particles in terms of dispersibility.

On the other hand, Al (OH) 3, Mg (OH), Al 2 O 3 improves flame retardancy as a flow improver, in particular, the reaction is started at around 180 ℃ compound is decomposed to produce water, thereby acting to turn off the fire. In particular, Al (OH) 3 is rich in the number of structures in the inorganic flame retardant not only excellent flame retardant effect, but also excellent in acid resistance and alkali resistance and cost advantages. It is preferable in terms of workability, dispersibility, etc. that the average particle diameter of said Al (OH) 3 is 1-10um, or 2-4um.

In addition, aluminum powder, iron, zinc, copper, etc. may perform a function of increasing the softening point of the low softening styrofoam particles and suppressing the generation of smoke during combustion.

Of these, flame retardant fillers such as expanded graphite, Al (OH) 3, aluminum powder and the like can provide the effect of increasing the thermal insulation as well. Therefore, the flame retardant filler may be included in an amount of 25 to 100 parts by weight, and the solvent may be included in an amount of 20 to 200 parts by weight based on 100 parts by weight of the thermoplastic resin.

It may further include components usable as flame retardants such as boric acid and sodium silicate within the scope of not inhibiting the effects of the present invention. If necessary, the foamed particles may further include a material capable of promoting fusion between the foamed particles during molding, and may include stearic acid, stearic acid triglyceride, hydroxystearic acid triglyceride, stearic acid sorbitan ester, and the like. Can be mentioned. These fusion promoters can be used within a content range that does not adversely affect the effects disclosed in the present invention.

The second adhesive included in the flame retardant layer may be, for example, 10 wt% or less, or 0.1 to 5 wt%, based on the amount of flame retardant used.

That is, in the present invention, the flame retardant layer basically includes the function of the flame retardant and additionally includes a foam adhesive. Thus further included adhesives can reinforce the effect of strengthening the adhesion between the beads as well as peeling the flame retardant layer.

If the boards made of the beads are broken, it can be seen that the flame-retardant beads that are joined by the enhanced welding force are broken and broken. On the other hand, conventionally, since the fusion strength between the flame retardant beads is weak, it can be confirmed that the flame retardant beads are not broken and are pulled while maintaining the bead shape on either of the two cutting surfaces.

The flame retardant beads may have a density of 0.5 g / cm 3 or less, 0.01 to 0.5 g / cm 3 or 0.05 to 0.2 g / cm 3. The density may vary depending on the amount of blowing agent or the ease of foaming, and the apparent density may vary due to the internal pore structure depending on the foamed shape.

The flame retardant bead may have an average diameter (width of the cross section) of 1 to 10 mm, or 2 to 5 mm, and in the case of the standard, may provide appropriate insulation.

EPS (Expanded Poly Stylene) flame retardant board according to an embodiment of the present invention may be a flame retardant board fused flame retardant beads formed by coating a flame retardant layer on the foam particles. At this time, the flame retardant beads are foam particles; An adhesive layer having a thin film thickness t2 by coating a first urethane foam adhesive on an outer surface of the foam particles; And a flame retardant layer including the second urethane foam adhesive and a flame retardant on the adhesive layer and coated with a thickness t3 thicker than t2, wherein when the radius of the foam particles is t1, t1 and t2 + t3 The ratio may be from 1: 0.0001 to 1: 0.2.

Thus, in the embodiment of the present invention, the foaming as a whole during the aging, coating, molding, drying process, but the particle size (hereinafter referred to as s1) before molding after coating increases to the particle size (hereinafter referred to as s2) after board production. At this time, it is preferable that s1 and s2 have a relationship of s2 ≧ s1 + s1 × 0.005.

In addition, the foaming may be further increased due to the effect of the foamed adhesive contained in the adhesive layer and the flame retardant layer as well as the degree of foaming of the foam particles themselves.

The board may have a flexural failure load measured according to KS M 3808: 2011 standard of 20N or more, and the compressive strength measured according to KS M 3808: 2011 standard may be 6N / cm2 or more.

Second aspect

A second aspect of the present invention relates to an apparatus for producing flame retardant beads and an apparatus for producing a board molded by fusing these flame retardant beads.

Dryer applied to the drying of the foam particles in the present invention can be carried out using the dryer 120 in FIG. 2 is a view schematically showing an apparatus for forming a flame retardant board using flame retardant beads according to an embodiment of the present invention.

Referring to Figure 2 below, Figure 2 is a foamer 110 for foaming the foamed styrene raw material, a dryer 120 for drying the foam particles delivered from the foamer 110 and in the dryer 120 In the apparatus for producing a flame retardant bead comprising a coating machine 130 for coating the transferred foam particles, the EPS raw material is put into the hopper of the extrusion cylinder, and is introduced into the foamer (110). The foamer 110 may use a variety of foaming type foaming machine, for example, may use a foamer of the pre-expander type.

The foamed particles delivered from the foamer 110 are dried in the dryer 120. The dryer 120 is dried by flowing the foam particles 11 by hot air in the drying body 121, when considering the drying efficiency, the drying body 121 is a fluidized bed reactor (Fluidized-bed dryer) Preference is given to using.

In consideration of the effect of the foam particles during rotational drying due to the temperature gradient difference in the upper surface and the bottom surface of the drying body 121, the drying body 121 is provided with a blower on the bottom surface of the drying body 121 and blows hot air It is preferable to provide the heating means 122 for heating the bottom of the.

At this time, the upper surface of the drying body 121 is provided with an external air blocking means to adjust the temperature gradient of the interior of the drying body 121, in particular the temperature gradient between the upper and lower inside.

If there is no air blocking means, especially in winter, when the cool air directly touches the upper surface of the dry body, the upper surface of the dry body has a severe temperature gradient and a lower temperature uniformity when the dry air is supplied.

Such external air blocking means may be provided in various ways such that the outdoor air does not affect the interior of the dry body.

As shown in FIG. 2, in one embodiment, the external air blocking means may include a housing 123 and an air stack 124. The housing 123 is provided on the upper surface of the dry body to provide a space for receiving air therein, the air stack 124 is provided on the housing,

The air stack exhausts air to the outside when the temperature inside the housing is high, but prevents the outside cold air from entering the interior. The external air blocking means may further include an air control unit 125 on the side surface. The air control unit 125 may appropriately adjust the amount of air inflow. The air conditioner may be provided by installing a bellows entrance on the side of the housing.

Although not shown in FIG. 2 for the sake of brevity, the above-described foamer 110 and the dryer 120 are preferably repeatedly provided to maximize foaming and drying effects. For example, the manufacturing apparatus of the present invention may be provided with a foamer and a dryer alternately in the order of the foamer 110, dryer 120, foamer (not shown), dryer (not shown). As a specific example, the manufacturing apparatus of the present invention is foamed in the order of the foamer 110, dryer 120, aging machine 130, foaming machine (not shown), dryer (not shown), aging machine (not shown) The tile, dryer, and aging machine may be alternately provided.

Delivery of the foam particles from the dryer 120 to the foamer (corresponding to the additional foamer not shown) may use a variety of methods known in the art, for example, a screw method may be used.

The foamed particles delivered from the dryer (not shown) are sprayed under high pressure while aging in the aging machine 130 to control humidity and prevent static electricity. The foamed particles delivered from the aging machine are coated with the adhesive and the flame retardant through the coater 140.

In one embodiment of the present invention, the coating machine 140 includes a stirring tank 141, a drying tank 143, a transfer tank 145, and a temperature gradient control means 150. 3 shows a conceptual diagram of a coating machine.

The stirring tank injects the first adhesive and the flame retardant into the foam particles to coat the foam particles to produce flame retardant beads. The stirring vessel is provided with an inlet for injecting the adhesive and the flame retardant which are simultaneously or sequentially supplied through the adhesive precedence tank 142 or the flame retardant trailing tank 144.

The flame retardant trailing tank 144 may include an adhesive supply tank 146 separate from the mixing tank for supplying them to the stirring tank 140 in a well-mixed state before use.

The drying tank 143 receives the flame-retardant beads coated in the stirring tank to dry. In the drying tank, the flame retardant beads are reduced to less than 50 ° C. and stirred for 100 to 500 seconds.

The transfer tank 145 is dried while transferring the flame retardant beads dried in the drying tank 143. At this time, it is dried while transferring over 100 to 300 seconds while maintaining below 50 ° C.

Temperature gradient control means 150 is adjusted so that there is no temperature gradient in the outer space where the coating machine is installed. In order to uniformly coat the flame retardant beads, it is necessary to control the temperature inside the coater.

In other words, it is necessary to eliminate the temperature gradient inside the coating machine in order to realize higher flame retardancy and fusion, and for this purpose, it is necessary to control the temperature around the coating machine, not inside the coating machine.

In the present invention, since the foaming of the flame retardant beads proceeds through the coating machine 140, when the temperature gradient inside the coating machine occurs, the foaming of the beads becomes uneven. To this end, a fine temperature gradient control means 150 is required in order to maintain the area where the wall surface of the coater contacts the outside air at a temperature similar to that inside the coater.

The temperature gradient adjusting means 150 includes a measuring unit 151, a control unit 153, and a heating device 155. That is, by installing a sensing unit that can measure the outside air temperature in the space around the coating machine, and sensing, if the constant temperature is not maintained, the control unit maintains the temperature by operating the heating device.

On the other hand, the stirring tank 140 may be a method of rotating up and down based on the central axis in the horizontal direction, but not limited to this may use a variety of coating methods for coating while stirring.

The flame retardant beads delivered from the coater 140 are dried in a dryer 150. The dryer 150 used here may include only the drying body 121 of the above-mentioned dryer 120, and if necessary, the air blocking means 123, 124, 125 or the bottom of the drying body 121, like the dryer 120, May include a heating means 122.

The foamed particles delivered from the dryer 150 provide aging and humidity control, antistatic performance, etc. using the aging machine 160. In this case, the usable aging machine 160 may use, for example, a multistage aging silo.

The flame retardant beads delivered from the aging machine 160 may be introduced into the board molding machine 170 and discharged by vacuum cooling after steaming under steam pressure. Such a board molding machine 170 may be a block molding machine or a mold molding machine, and these molding machines are preferably performed under a heating chamber because it can efficiently provide further foaming by an adhesive or the like.

<Third aspect>

A third aspect of the invention relates to a method of making flame retardant beads. These flame retardant beads are prepared by foaming a foamed styrene raw material, coating an adhesive on the outer surface thereof to make a flame retardant binding site, and then attaching a flame retardant.

Specifically, the manufacturing method includes steps 1-1, 1-2, 1-3, 1-4, 1-5, and 1-8. The name of each step is a name given to distinguish each step from other steps and does not include all technical meanings of each step.

Step 1-1 is a step of foaming the foamed styrene raw material in the foaming machine.

As the foamed styrene raw material used in the present invention, for example, an average diameter of 0.5 to 1.5mm can be used.

For example, the foaming may be performed at 80 ° C. or more, steam pressure of 0.5 kg / cm or less, or 0.1 to 0.2 kg / cm, steam of 120 seconds or less, or 100 to 120 seconds.

Step 1-2 controls the temperature gradient between the center temperature inside the drying body and the upper temperature inside the drying body by blocking the upper outside air of the drying body while drying the foam particles delivered in the foaming step in the drying body. At the same time, by blowing hot air from the bottom of the drying body to heat the bottom of the drying body.

At this time, the temperature of the drying body is preferably hot air dried at 30 degrees or more, and by foaming and drying in this way it can be foamed to about 70 ~ 90 times the expansion ratio based on the foamed styrene raw material.

In step 1-3, the foamed particles passed through the dry body are aged at a temperature of 40 ° C. or lower for 3 to 12 hours. It is preferable to proceed with a multi-stage silo method in consideration of the aging efficiency, and more preferably to control the humidity by intermittently high pressure injection of water.

In steps 1-4, the mature raw material is added to a secondary foamer (using the foamer described above or a separate foamer can be used) in a screw manner to perform further foaming, and then dried. At this time, the additional foaming conditions can be carried out at 80 ~ 90 ℃ to further advance the foaming less carried out in the previous foaming, and then using a dry body as described above (with the method of blowing the hot air from the upper air block and the bottom). Alternatively, hot air drying is preferably performed while maintaining a drying chamber temperature of 30 ° C. or higher using a separate drying body.

By repeating the foaming and drying in this way it is possible to foam up to about 100 ~ 130 times the expansion ratio based on the first used styrene foam.

In steps 1-5, the foamed particles passed through the additional drying body are aged at 0 to 40 ° C. for 3 to 12 hours. It is preferable to proceed with a multi-stage silo method in consideration of the aging efficiency, and it is more preferable to control the humidity at the same time by spraying water at high pressure intermittently to prevent correction.

Steps 1-6 are steps of applying a urethane foam adhesive to the outer surface of the obtained foam particles.

The use of the urethane foam adhesive in the range of 3 to 20 parts by weight, 3 to 10 parts by weight, or 4 to 8 parts by weight based on 100 parts by weight of the foamed particles makes the flame retardant bind to the coating described below. It is preferable to be able to cause further foaming in the step or forming step.

If necessary, thermally expandable microspheres may be included in the urethane foam adhesive in an amount of 10 wt% or less based on the adhesive. The thermally expandable microspheres are compatible with the urethane foam adhesive and correspond to materials suitable for carrying out further foaming in the coating step described below, in particular the molding step.

These thermally expandable microspheres have the form of a capsule having a hollow and a shell and contain a liquid in the hollow having a boiling point below the softening temperature of the shell for foaming. Such liquid may be a hydrocarbon, and more preferably a hydrocarbon having a boiling point of less than 60 ° C. at atmospheric pressure. In one example, the preferred foam liquid therein is isobutane.

On the other hand, the acryl-based copolymer constitutes a shell, which is powdery at room temperature, but expands the capsule by vaporization of the liquefied hydrocarbon in the hollow at high temperature and may be applied as a blowing agent. On the other hand, unlike conventional chemical blowing agents have the advantage that the gas is not exposed to the surface. Such thermally expandable microspheres are commercially available from Akzo Nobel under the trade name Expancel 980 DU 120.

Steps 1-7 are steps of applying a flame retardant containing expanded graphite after the adhesive application step.

The flame retardant containing the expanded graphite may include various materials disclosed in the above-described <first aspect>, and for example, may include an acrylic adhesive resin such as a flame retardant filler including expanded graphite, a polysol, and a PVA-based resin. Do.

The flame retardant is stored in a separate storage tank until spraying, mixed before use, mixed well using a homogenizer, or evenly mixed with agitation, and sprayed so that the foam particles 11 are not in direct contact with the external gas. At the same time, the flame retardant layer 13 can be formed with a uniform thickness, which is more preferable.

In addition, from the viewpoint of forming the flame retardant layer 13 to a uniform thickness, it is preferable to perform the spraying in such a way that it is possible to apply evenly evenly, such as a nozzle or a syringe.

The flame retardant may be used within the range of 50 to 250 parts by weight, 100 to 200 parts by weight, or 100 to 150 parts by weight based on 100 parts by weight of the foamed particles, in which the foamed particles 11 do not directly contact external gas. It is preferable because the flame retardant layer 13 can be formed to the thickness which is not enough.

In addition, the second adhesive may be included in an amount of 10 wt% or less, or 0.1 to 5 wt%, based on the amount of the flame retardant, thereby improving bonding strength when the foam particles and the flame retardant layer are bonded. The 2nd adhesive agent used at this time can use the urethane type foam adhesive mentioned above, and may contain thermally expansible microsphere as needed.

Steps 1-6 and 1-7 may be performed simultaneously or sequentially as necessary.

Application in these steps is carried out with stirring for 100 to 300 seconds, 150 to 250 seconds, or 150 to 200 seconds at 40 to 60 ° C, or 45 to 55 ° C, followed by 200 seconds at 30 to 50 ° C, or 35 to 45 ° C. Above, preferably 200-300 seconds, or 200-250 seconds while stirring the coated material is dried and then transported for additional 100-300 seconds, preferably 150-250 seconds at 30 ~ 50 ℃, or 35 ~ 45 ℃ Further drying is preferred.

If necessary, as the first step 1-8, the step of aging for 2 to 5 hours at 40 ° C. or less may be added.

Fourth aspect

A fourth aspect of the present invention relates to a method of manufacturing a flame retardant board using the manufactured flame retardant beads. In this case, as well as the flame retardant beads can be prepared using the foamed particles prior to forming the adhesive layer and the flame retardant layer, in this case it is possible to manufacture a general board rather than a flame retardant board.

Specifically, the method for manufacturing a flame retardant board includes steps 2-1, 2-2, 2-3, 2-4, 2-5, and 2-10. The name of each step is a name given to distinguish each step from other steps and does not include all technical meanings of each step.

Step 2-1 is a step of foaming the expanded styrene raw material.

In the present invention, the foaming may be performed under, for example, a foaming temperature of 90 ° C. or higher, a vapor pressure of 0.5 kg / cm or less, or 0.1 to 0.2 kg / cm, steam of 120 seconds or less, or 100 to 120 seconds.

Step 2-2 controls the temperature gradient between the central temperature inside the drying body and the upper temperature inside the drying body by blocking the upper outside air of the drying body while drying the foam particles delivered in the foaming step in the drying body. At the same time, by blowing hot air from the bottom of the drying body to heat the bottom of the drying body.

At this time, the temperature of the drying body is preferably hot air dried at 30 ℃ or more, and by foaming and drying in this way it is possible to foam the foamed styrene raw material to a foaming ratio of 70 to 90 times.

In step 2-3, the foamed particles having passed through the dry body are aged at a temperature of 40 ° C. or lower for 3 to 12 hours. It is preferable to proceed with a multi-stage silo method in consideration of the aging efficiency, and more preferably to control the humidity by intermittently high pressure injection of water.

In step 2-4, the mature raw materials are added to the secondary foaming machine (using the foaming machine described above or using a separate foaming machine) by screwing to perform additional foaming and then drying. At this time, the additional foaming conditions can be carried out at 80 ~ 90 ℃ to further advance the foaming less carried out in the previous foaming, and then using a dry body as described above (with the method of blowing the hot air from the upper air block and the bottom). It is preferable that the hot air is dried while maintaining a drying chamber temperature of 30 ° C. or higher using a separate drying body.

As the foaming and drying are repeated in this manner, the foamed styrene raw material may be foamed at a foaming ratio of 100 to 130 times.

In step 2-5, the foamed particles passed through the additional drying body are aged for 3 to 12 hours at 0 to 40 ° C. It is preferable to proceed with a multi-stage silo method in consideration of the aging efficiency, and it is more preferable to control the humidity at the same time by spraying water at high pressure intermittently to prevent correction.

Step 2-6 is a step of applying a urethane foam adhesive to the outer surface of the obtained foam particles.

The use of the urethane foam adhesive in the range of 3 to 20 parts by weight, 3 to 10 parts by weight, or 4 to 8 parts by weight based on 100 parts by weight of the foamed particles makes the flame retardant bind to the coating described below. It is preferable to be able to cause further foaming in the step or forming step.

If necessary, thermally expandable microspheres may be included in the urethane foam adhesive in an amount of 10 wt% or less based on the adhesive. The thermally expandable microspheres are compatible with the urethane foam adhesive and correspond to materials suitable for carrying out further foaming in the coating step described below, in particular the molding step.

These thermally expandable microspheres have the form of a capsule having a hollow and a shell and contain a liquid in the hollow having a boiling point below the softening temperature of the shell for foaming. Such liquid may be a hydrocarbon, and more preferably a hydrocarbon having a boiling point of less than 60 ° C. at atmospheric pressure. In one example, the preferred foam liquid therein is isobutane.

On the other hand, the acryl-based copolymer constitutes a shell, which is powdery at room temperature, but expands the capsule by vaporization of the liquefied hydrocarbon in the hollow at high temperature and may be applied as a blowing agent. On the other hand, unlike conventional chemical blowing agents have the advantage that the gas is not exposed to the surface. Such thermally expandable microspheres are commercially available from Akzo Nobel under the trade name Expancel 980 DU 120.

Step 2-7 is a step of spraying the flame retardant by mixing the flame retardant containing expanded graphite evenly after the adhesive coating step.

The flame retardant containing the expanded graphite may include various related materials described in the first aspect described above, and for example, it is preferable to include an acrylic adhesive resin such as a flame retardant filler including polylated graphite, a polysol, and a PVA-based resin. .

These materials are stored in a separate storage tank until the flame retardant is sprayed, mixed before use, mixed well using a homogenizer, or evenly mixed and sprayed, so that the foam particles 11 do not directly contact external gases. It is preferable because the flame-retardant layer 13 can be formed uniformly on the whole surface in thickness.

In addition, from the viewpoint of forming the flame retardant layer 13 to a uniform thickness, it is preferable to perform the spraying in such a way that it is possible to apply evenly evenly, such as a nozzle or a syringe.

The flame retardant may be used within the range of 50 to 250 parts by weight, 100 to 200 parts by weight, or 100 to 150 parts by weight based on 100 parts by weight of the foamed particles, in which the foamed particles 11 do not directly contact external gas. It is preferable because the flame retardant layer 13 can be formed to the thickness which is not enough.

In addition, the adhesive may be included in the range of 10% by weight or less, or 0.1 to 5% by weight, based on the amount of the flame retardant used to improve the bonding strength of the foamed particles and the flame retardant layer. The adhesive used at this time can use the urethane type foam adhesive mentioned above, and may contain thermally expansible microsphere as needed.

Steps 2-6 and 2-7 may be performed simultaneously or sequentially as necessary.

Application in these steps is carried out with stirring for 100 to 300 seconds, 150 to 250 seconds, or 150 to 200 seconds at 40 to 60 ° C, or 45 to 55 ° C, followed by 200 seconds at 30 to 50 ° C, or 35 to 45 ° C. Above, preferably 200-300 seconds, or 200-250 seconds while stirring the coated material is dried and then transported for additional 100-300 seconds, preferably 150-250 seconds at 30 ~ 50 ℃, or 35 ~ 45 ℃ Further drying is preferred.

If necessary, the step of aging for 2 to 5 hours at 40 ° C. or less may be added as steps 2-8.

In the second and second steps, the flame retardant beads are immediately added to the board forming after the flame retarding ripening step or are stored and stored until forming. As the board forming used here, for example, the raw material is vacuum-filled, and then, for example, steam pressure of 1 to 5 kg / cm, or 1 to 3 kg / cm, primary steam 10 to 20 seconds or 10 to 15 seconds, secondary steam 1 to 10 seconds, or 1 to 5 seconds, vacuum cooling 40 to 50 seconds after the process can be carried out, may be block molding or mold molding as needed.

As described above, the present invention provides a technique for enhancing the bonding strength of the beads constituting the board, specifically, the adhesion of the beads constituting the board in the present invention by the structure and composition of the adhesive layer and the flame retardant layer Is strengthened. That is, the adhesive layer in the present invention serves to bond the foam particles and the flame retardant layer. The reason for providing the adhesive layer as described above is to improve the bonding strength when bonding the foam particles and the flame retardant layer by forming the adhesive layer evenly over the entire surface of the foam particles. In this case, since the flame retardant layer has a relatively low adhesive strength compared to the adhesive layer, when the adhesive layer is not provided, the flame retardant layer may be peeled off and the flame retardant effect may be reduced, thereby preventing such peeling from the flame retardant bead manufacturing step.

In addition, to help prevent such peeling, the flame retardant layer basically includes the function of the flame retardant and additionally includes an adhesive. Thus further included adhesives can reinforce the effect of strengthening the adhesion between the beads as well as peeling the flame retardant layer. For reference, when cutting the board by hand, it can be seen that the flame-retardant beads joined by the enhanced welding force are split and cut. On the other hand, conventionally, since the fusion strength between the flame retardant beads is weak, it can be seen that the flame retardant beads are not broken and are pulled while maintaining the bead shape on either of the two cutting surfaces.

In addition, by increasing the degree of foaming of the foam particles, the adhesion is enhanced. The higher the foaming of the foamed particles, the larger the particle size, and the greater the force that the foamed particles collide with each other to achieve high density.

Thus, in the embodiment of the present invention, the foaming as a whole during the aging, coating, molding, drying process, but after the coating, the particle size (hereinafter referred to as s1) is increased to the particle size after the board manufacturing (hereinafter referred to as s2). At this time, it is preferable that s1 and s2 have a relationship of s2 ≧ s1 + s1 × 0.005.

In addition, the foaming may be further increased due to the effect of the foamed adhesive contained in the adhesive layer and the flame retardant layer as well as the degree of foaming of the foam particles themselves.

In fact, as a result of testing the flexural fatigue strength of the molded board according to the embodiment of the present invention through Figure 5 it can be seen that the bending is not cut only 180 °. In addition, it can be seen from FIG. 6 that the quasi-non-flammable test result in the molded board according to the embodiment of the present invention is superior to the quasi-non-flammable test result in the commercially available board.

<Fifth aspect>

A fifth aspect of the present invention is to provide a sandwich panel by bonding the upper and lower metal plates to the board formed of the above-described flame retardant beads.

Specific manufacturing methods include steps 3-1, 3-2, 3-3, 3-4, 3-5 to 3-10. The name of each step is a name given to distinguish each step from other steps and does not include all technical meanings of each step.

Step 3-1 is a step of foaming the expanded styrene raw material.

In the present invention, the foaming may be performed under, for example, a foaming temperature of 90 ° C. or higher, a vapor pressure of 0.5 kg / cm or less, or 0.1 to 0.2 kg / cm, steam of 120 seconds or less, or 100 to 120 seconds.

Step 3-2 controls the temperature gradient between the central temperature inside the drying body and the upper temperature inside the drying body by blocking the upper outside air of the drying body while drying the foam particles delivered in the foaming step in the drying body. At the same time, by blowing hot air from the bottom of the drying body to heat the bottom of the drying body.

At this time, the temperature of the drying body is preferably hot air dried at 30 ℃ or more, and by foaming and drying in this way it is possible to foam the foamed styrene raw material to a foaming ratio of 70 to 90 times.

In step 3-3, the foamed particles having passed through the drying body are aged for 3 to 12 hours at a temperature of 40 degrees or less. It is preferable to proceed with a multi-stage silo method in consideration of the aging efficiency, and more preferably to control the humidity by intermittently high pressure injection of water.

In step 3-4, the mature raw materials are added to the secondary foaming machine (using the foaming machine described above or using a separate foaming machine) in a screw manner to perform additional foaming and then drying. At this time, the additional foaming conditions can be carried out at 80 ~ 90 ℃ to further advance the foaming less carried out in the previous foaming, and then using a dry body as described above (with the method of blowing the hot air from the upper air block and the bottom). It is preferable that the hot air is dried while maintaining a drying chamber temperature of 30 ° C. or higher using a separate drying body.

As the foaming and drying are repeated in this manner, the foamed styrene raw material may be foamed at a foaming ratio of 100 to 130 times.

In step 3-5, the foamed particles passed through the additional drying body are aged at 0 to 40 ° C. for 3 to 12 hours. It is preferable to proceed with a multi-stage silo method in consideration of the aging efficiency, and it is more preferable to control the humidity at the same time by spraying water at high pressure intermittently to prevent correction.

Step 3-6 is a step of applying a urethane foam adhesive to the outer surface of the obtained foam particles.

The use of the urethane foam adhesive in the range of 3 to 20 parts by weight, 3 to 10 parts by weight, or 4 to 8 parts by weight based on 100 parts by weight of the foamed particles makes the flame retardant bind to the coating described below. It is preferable to be able to cause further foaming in the step or forming step.

If necessary, thermally expandable microspheres may be included in the urethane foam adhesive in an amount of 10 wt% or less based on the adhesive. The thermally expandable microspheres are compatible with the urethane foam adhesive and correspond to materials suitable for carrying out further foaming in the coating step described below, in particular the molding step.

These thermally expandable microspheres have the form of a capsule having a hollow and a shell and contain a liquid in the hollow having a boiling point below the softening temperature of the shell for foaming. Such liquid may be a hydrocarbon, and more preferably a hydrocarbon having a boiling point of less than 60 ° C. at atmospheric pressure. In one example, the preferred foam liquid therein is isobutane.

On the other hand, the acryl-based copolymer constitutes a shell, which is powdery at room temperature, but expands the capsule by vaporization of the liquefied hydrocarbon in the hollow at high temperature and may be applied as a blowing agent. On the other hand, unlike conventional chemical blowing agents have the advantage that the gas is not exposed to the surface.

Such thermally expandable microspheres are commercially available from Akzo Nobel under the trade name Expancel 980 DU 120.

Step 3-7 is a step of spraying the flame retardant by mixing the flame retardant containing expanded graphite evenly after the adhesive coating step.

The flame retardant containing the expanded graphite may include various related materials described in the first aspect described above, and for example, it is preferable to include an acrylic adhesive resin such as a flame retardant filler including polylated graphite, a polysol, and a PVA-based resin. .

These three materials are stored in a separate storage tank until the flame retardant is sprayed, mixed before use, mixed well using a homogenizer, or evenly mixed and sprayed, so that the foamed particles 11 do not come into direct contact with the external gas. The flame retardant layer 13 can be formed with a thickness of and substantially uniform thickness, which is preferable.

In addition, from the viewpoint of forming the flame retardant layer 13 to a uniform thickness, it is preferable to perform the spraying in such a way that it is possible to apply evenly evenly, such as a nozzle or a syringe.

The flame retardant may be used within the range of 50 to 250 parts by weight, 100 to 200 parts by weight, or 100 to 150 parts by weight based on 100 parts by weight of the foamed particles, in which the foamed particles 11 do not directly contact external gas. It is preferable because the flame retardant layer 13 can be formed to the thickness which is not enough.

In addition, the adhesive may be included in the range of 10% by weight or less, or 0.1 to 5% by weight, based on the amount of the flame retardant used to improve the bonding strength of the foamed particles and the flame retardant layer. The adhesive used at this time can use the urethane type foam adhesive mentioned above, and may contain thermally expansible microsphere as needed.

Steps 3-6 and 3-7 may be simultaneously or sequentially performed as necessary, and more preferably, sequentially.

Application in these steps is carried out with stirring for 100 to 300 seconds, 150 to 250 seconds, or 150 to 200 seconds at 40 to 60 ° C, or 45 to 55 ° C, followed by 200 seconds at 30 to 50 ° C, or 35 to 45 ° C. Above, preferably 200-300 seconds, or 200-250 seconds while stirring the coated material is dried and then transported for additional 100-300 seconds, preferably 150-250 seconds at 30 ~ 50 ℃, or 35 ~ 45 ℃ Further drying is preferred.

If necessary, as a third step 3-8 may be added to the step of aging for 2-5 hours at 40 ℃ or less.

In the third to third stages, the flame retardant beads are immediately added to the board forming after the flame retarding ripening step or stored and stored until forming. As the board forming used here, for example, the raw material is vacuum-filled, and then, for example, steam pressure of 1 to 5 kg / cm, or 1 to 3 kg / cm, primary steam 10 to 20 seconds or 10 to 15 seconds, secondary steam 1 to 10 seconds, or 1 to 5 seconds, vacuum cooling 40 to 50 seconds after the process can be carried out, may be block molding or mold molding as needed.

In step 3-10, the molded board is bonded to a metal plate to form a sandwich panel.

As the manufacturing apparatus used in the manufacturing method, a sandwich panel manufacturing apparatus (not shown) may be additionally added to the apparatus for manufacturing a flame retardant board disclosed in the above-described third aspect. For example, a pre-foaming device for pre-expanding the foamed styrene raw material, a first dryer for drying the pre-expanded particles delivered from the pre-expander, a foamer for foaming the pre-expanded particles delivered from the dryer, in the foaming machine A second dryer for drying the transferred foam particles, a coating machine for coating the foam particles delivered from the second dryer with a flame retardant, a board molding machine for board molding the coated foam particles delivered from the coating machine, a board transferred from the board molding machine An apparatus for manufacturing a sandwich panel may include a third dryer for drying the panel, and a panel molding machine for sandwiching the board transferred from the third dryer.

An apparatus for producing a sandwich panel including a panel molding machine for sandwiching the board may include, for example, a foamer for foaming foamed styrene raw material, a dryer for drying the foamed particles delivered from the foamer, and foaming delivered from the dryer. Coating machine for forming flame retardant beads by coating the particles, and a molding machine for forming the flame retardant beads to manufacture a flame retardant board, a board dryer for drying the molded board and a sandwich panel maker formed by bonding a metal plate to the board transferred from the board dryer It may be configured as an apparatus for manufacturing a sandwich panel comprising a.

At this time, the dryer, the stirring tank for preparing a flame retardant bead by injecting a first adhesive and a flame retardant to the foam particles to coat the foam particles; A drying tank drying the flame retardant beads coated in the stirring tank; And a transfer tank for drying while transferring the flame retardant beads dried in the drying tank, and a measuring unit for measuring the outside air temperature of the surrounding area of the coater such that the internal space of the coater does not generate a temperature gradient due to an external environment. It has a temperature gradient control means including a control unit for controlling the temperature by receiving the temperature signal of the measuring unit, and a heating device for heating by the control unit to provide enhanced fusion between the flame retardant beads in the board and at the same time improved It can provide flame retardant.

As described above, the coater may include an adhesive precedent tank for supplying a first adhesive, and a flame retardant aftertank tank for supplying a flame retardant to the coater.

The flame retardant may be used by mixing expanded graphite, polysol and an acrylic binder, the flame retardant mixing tank may include an adhesive supply tank for supplying a second adhesive. Here, the second adhesive may further foam the flame retardant beads through the drying tank, the transfer tank, and the board dryer after the stirring tank, for example, using a urethane foam adhesive such as methylene diphenyl diisocyanate (MDI) material. It is preferable.

At this time, it is preferable that the stirring tank sequentially injects the adhesive and the flame retardant from the top to help even mixing of the flame retardant.

FIG. 7 is a photograph of a flame retardant bead remaining on a metal plate when a sandwich panel is molded according to an embodiment of the present invention, and a picture of a flame retardant bead remaining on a metal plate when a sandwich panel is commercially available. to be.

Referring to (a) of FIG. 7, it was confirmed that almost no flame retardant beads remained on the metal plate, while (b) it was confirmed that the flame retardant beads adhered to almost the entire surface of the metal plate.

Sixth aspect

A sixth aspect of the present invention relates to a sandwich panel formed by bonding a metal plate and a board with an adhesive material and forming a panel.

The sandwich panel corresponds to an insulating material formed by bonding a flame retardant board formed by molding a flame retardant bead formed by coating a flame retardant through an adhesive layer on an outer surface of foam particles formed by foaming a foamed styrene raw material and a metal plate.

8 is a view schematically showing an apparatus for manufacturing a sandwich panel according to an embodiment of the present invention. Here, the metal plate, the board, and the adhesive layer of the metal plate and the board can be continuously transferred using a rubber roller to provide convenient workability.

In addition, the metal plate can be prepared in various kinds as necessary, such as iron plate, SUS.

Referring to FIG. 8, first heating parts 184a and 184b for preheating the metal plates 182a and 182b are included. The first heating unit 184a, 184b is for expressing sufficient adhesive ability to the adhesive sprayed on the surface of the metal plate 182a, 182b, for example, various heating means capable of directly heating the surface of the metal plate (182a, 182b) Can be. For example, it is preferable to use a heating wire because it can easily provide heating performance.

Adhesive preforms 183a and 183b are provided between the preheated metal plates 182a and 182b and the board 181 to spray urethane foam adhesive.

The injection may use a nozzle or the like in consideration of injection performance.

The adhesive layers of the metal plates 182a and 182b and the board 181 are heated through the second heating units 185a and 185b.

The second heating unit 185a, 185b is preferably capable of providing the effect of additional foaming due to heating without causing deformation of the rubber roller for transportation, for example, to blow hot air through the air blower Can be.

On the other hand, in consideration of the convection difference between the upper and lower adhesive layers, the number of the lower second heating parts 185b is preferably provided twice or more than the number of the upper second heating parts 185a. For example, when six lower side second heating parts 185b are provided between the lower side rubber rollers for conveyance, three upper side second heating parts 185a are provided between the upper side rubber rollers for conveyance. Can be.

A method of manufacturing a sandwich panel using the manufacturing apparatus is one example as follows:

A concrete sandwich panel manufacturing method includes steps 4-1, 4-2, and 4-3. The name of each step is a name given to distinguish each step from other steps and does not include all technical meanings of each step. Here, the metal plate, the board, and the adhesive layer of the metal plate and the board can be continuously transferred using a rubber roller to provide convenient workability. In addition, the metal plate may include an iron plate, SUS, and the like.

Step 4-1 is a step of preheating the metal plate continuously supplied.

Metal plates used in the present invention are supplied from the top and bottom of the board, respectively. Among them, the metal plate supplied from the upper part of the board may be supplied through a conveying roll mounted at the upper end of the board, and the metal plate supplied from the lower part of the board may be supplied through a supply roll mounted at the lower end of the board.

Here, the pre-heating is to directly heat the surface by using a hot wire or the like, where the heating temperature is sufficient to warm enough to spray the urethane foam adhesive to be exerted on the surface.

As a specific example, the metal plate supplied from the upper portion of the board through the conveying roll preheats the surface of the metal plate using an upper heating wire, and the metal plate supplied from the lower portion of the board through the supply roll uses the lower heating wire. The surface of can also be preheated.

Step 4-2 is a step of spraying a urethane foam adhesive between the pre-heated metal plate and the board.

At this time, the adhesive spraying portion is preferably provided on each of the upper and lower sides of the preheated metal plate.

In addition, the urethane foam adhesive to be used may include monomeric diisocyanate, for example, such a urethane foam adhesive, and specific examples thereof include methylene diphenyl diisocyanate (MDI) material.

The methylenediphenyl diisocyanate is a material obtained by treating phosgene (COCl 2) with diphenylmethanediamine produced by condensation of aniline and formaldehyde, and considering the storage properties and ease of use, the polymeric MDI (MDI) and the modi MDI ( Various types of MDIs, such as modified MDI), monomeric MDI, and pure MDI (prepolymer), are prepared. In the present invention, all of these various types of MDI may be used, and the form is not particularly limited.

The methylene diphenyl diisocyanate is relatively small and easily dispersed compared to other hydrophobic resin components, and isocyanate group (-NCO) included in the molecular structure reacts with a compound having active hydrogen to generate a urethane bond and urea bond. It is possible to remove the moisture in the steam and increase the crosslinking density of the hydrophobic resin to improve the adhesiveness, it is also possible to improve the mechanical properties of the flame retardant beads.

Thermally expandable microspheres may be used in the urethane foam adhesive in an amount of 10 wt% or less based on the adhesive. The thermally expandable microspheres are compatible with the urethane foam adhesive and correspond to materials suitable for carrying out further foaming in the coating step described below, in particular the molding step.

These thermally expandable microspheres have the form of a capsule having a hollow and a shell and contain a liquid in the hollow having a boiling point below the softening temperature of the shell for foaming. Such liquid may be a hydrocarbon, and more preferably a hydrocarbon having a boiling point of less than 60 ° C. at atmospheric pressure. In one example, the preferred foam liquid therein is isobutane.

On the other hand, the acryl-based copolymer constitutes a shell, which is powdery at room temperature, but expands the capsule by vaporization of the liquefied hydrocarbon in the hollow at high temperature and may be applied as a blowing agent. On the other hand, unlike conventional chemical blowing agents have the advantage that the gas is not exposed to the surface.

Such thermally expandable microspheres are commercially available from Akzo Nobel under the trade name Expancel 980 DU 120.

Step 4-3 is a step of further heating the adhesive layer of the metal plate and the board to provide additional foaming.

Under the adhesive layer between the metal plate and the board, it is preferable to provide a method of indirectly heating the adhesive layer without deformation of a rubber roller by blowing hot air into a tuyere provided on the bottom surface of the metal plate. Foaming can be performed, resulting in the effect of further improving the fusion rate of the foamed particles fused in the board.

Hereinafter, the Example of this invention is described in detail. The following examples are intended to illustrate the invention, but are not intended to limit the invention thereto.

<Example>

The following materials were prepared for the preparation of flame retardant beads of the examples.

EPS: 50kg of expanded polystyrene with an average diameter of 0.5 ~ 1.5mm

Adhesive 1: 3 kg MDI

Adhesive 2: Akzo Nobel company name Expancel 980 DU 120 0.3 kg

Flame retardant: 55 kg homogenizer mixture of expanded graphite, polysol, PVA resin

<Example 1>

Preparation of flame retardant beads

Referring to the apparatus of FIG. 2, the EPS raw material was filled into the foaming machine 110, and the EPS raw material was preexpanded and foamed under conditions of a temperature of 90 ° C or higher, a steam pressure of 0.1 to 0.2 kg / cm, and steam for 100 seconds.

Then, the particles pre-foamed in the foaming machine 110 was delivered into the drying body 121 of the dryer 120. At this time, the dryer 120, as shown in Figure 2, the temperature control box (123, 124, 125) is attached to the top of the drying body 121 as the outside air blocking means, the heating means 122 for blowing hot air through the air blower on the bottom surface It was used as a structure provided.

Through the structure of the dryer 120 was hot air dried while uniformly adjusting the internal temperature of the drying body 121 to 30 ℃ or more.

The expansion ratio of the foam particles thus obtained was 75 times.

Then, the foam particles delivered from the dryer 120 were aged at 40 ° C. or lower for 3 to 12 hours in a multi-stage silo aging machine 130 to control the humidity by high pressure injection of water.

The raw material transferred from the aging machine 130 was introduced into a secondary foaming machine (not shown) by a screw method and foamed while maintaining 80 to 90 ° C.

Then in the secondary foamer (not shown) the foam particles were delivered into the drying body (not shown) of the additional dryer. At this time, the dryer used also has a temperature control box attached to the top of the drying body (not shown) as an external air blocking space (not shown), and the heating means for blowing hot air through the air blower at the bottom thereof. Used.

In the dryer, hot air drying was performed while uniformly adjusting the internal temperature of the drying body to 30 ° C. or higher. The expansion ratio of the foam particles thus obtained was 110 times.

Subsequently, the foamed particles delivered from the additional dryer were aged at a temperature of 0 to 40 ° C. for 3 to 12 hours in a multi-stage silo aging machine (not shown) to control the humidity by high-pressure spraying water to prevent static electricity.

Next, the aged foamed particles (corresponding to reference numeral 11 of FIG. 1) were sequentially coated by stirring the adhesive and the flame retardant at 50 ° C. for 180 seconds using the coater 140.

That is, the adhesive 1 was pre-added from the leading tank 142 through the inlet provided as the upper side inlet of the coating machine 140 to form the adhesive layer 12, and then mixed the material from the raw material storage tank 144 including expanded graphite. Then, a mixed solution of the adhesive 2 supplied from the adhesive 2 storage tank 146 was added to the coating machine 140 by adding the mixed flame retardant to which the mixture was evenly mixed to form the flame retardant layer 13.

The coated particles were dried by stirring at 40 ° C. for 230 seconds and then further dried while transferring at 40 ° C. for 200 seconds to form a thin adhesive layer 12 surrounding the foam particles 11 as shown in FIG. 1. In addition, a flame retardant bead 10 having a structure in which a flame retardant layer 13 surrounding the foam particles 11 and the adhesive layer 12 was formed as a whole was obtained.

At this time, the temperature gradient control means was used to adjust the temperature of the external space in which the device is installed in order to reduce the internal temperature gradient of the devices in which the flame retardant beads are manufactured. That is, by installing the sensing unit 151 that can measure the outside air temperature in the space around the coating machine, and if it does not maintain a constant temperature, the control unit 153 maintains the temperature by operating the heating device 155.

Subsequently, while further passing through the multi-stage SilO aging machine 150, further aged for 2-5 hours at 40 ℃ or less to obtain a flame retardant bead (10).

At this time, the radius t1 of the foam particles 11, the thickness t2 of the adhesive layer 12, and the thickness t3 of the flame retardant layer 13 were found to be t1: t2 + t3 = 1: 0.2.

<Example 2>

Manufacture of flame retardant boards

2 and 3, the flame retardant beads 10 prepared in Example 2 were vacuum-filled into the mold molding machine 170, and the steam pressure 2kg / cm, the first steam 12 seconds, the secondary steam 2.5 seconds, After vacuum cooling 40 ~ 50 seconds process was discharged to produce a board of thickness 50mm and 120mm, respectively.

The produced boards were dried for 2 hours at 40-50 ° C. in the primary drying room, then transferred to the secondary drying room, aged at 20 ° C. or more for 24 hours, and then cut and stored.

It was also confirmed that the relationship between s2 ≥ s1 + s1 × 0.005 was also satisfied when the average diameter before forming the flame retardant beads was s1 and the average diameter after board production of the flame retardant beads was s2.

<Example 3>

Manufacture of sandwich panels

With reference to the apparatus of FIG. 8, the iron plates 182a and 182b were joined to the upper and lower parts of the board 181 by urethane foam adhesives 183a and 183b, and the sandwich panel was produced.

First, iron plates 182a and 182b continuously supplied through a rubber feed roller (not shown) were heated through upper and lower heating wires 184a and 184b as direct heating units. At this time, the upper iron plate 182a is supplied through the upper conveying roll of the board 181, the lower iron plate 182b is supplied through the lower or side supply roll of the board (181).

Urethane foam adhesive was sprayed on the upper and lower parts of the heated iron plates 182a and 182b, and the upper and lower parts of the board were joined.

The adhesive layer of the iron plate and the board 181 as an indirect heating unit by blowing hot air through upper and lower air passages (185a, 186b) provided between the rubber feed rollers to maximize the adhesive performance. Here, the upper blower 185a is provided with three, and the lower blower 185b is provided with six to overcome the difference between upper and lower convection.

Experimental Example 1

The board of Example 2 and a commercially available flame retardant board was produced, the cross section was cut by hand to check the adhesion between the beads in the board, and the results are shown in FIG. 4.

Figure 4 is a photo (a) showing that the beads are broken when broken as a result of strong fusion of the flame retardant beads in the board formed in accordance with the second embodiment of the present invention is broken as a result of weak fusion of the flame retardant beads in the market on the market The photograph (b) shows that the beads are located on either side of the cut surface while maintaining the spherical shape.

In the case of the present invention through Figure 4 it was confirmed that the flame retardant beads were more strongly fused.

In other words, even when the board is broken, the fusion between the beads is strong, so that the fracture is not made between the beads, but the beads themselves are broken and the ratio of the beads reaches 70% to 95% and 80% to 90%.

Experimental Example 2

The board of Example 2 and the commercially available to manufacture a semi-non-combustible board to measure the bending fatigue strength and the results are shown in FIG.

Figure 5 is a photograph showing the flexural fatigue strength characteristics results for the board formed in accordance with Example 2 of the present invention, the board sold on the market is broken and the result is not only bent even if folded at 180 ° I could confirm it. It is inferred that this is the result of improved density and fusion in accordance with the techniques of the present invention.

Experimental Example 3

The quasi-non-flammable performance of the board of Example 2 and the quasi-non-combustible board sold in the market was confirmed and the results are shown in FIG. Specifically, heating was performed at 750 ° C. for 10 minutes, and it was checked whether or not it was punched.

Figure 6 is a photograph (a) showing the results of the quasi-non-flammable experiment in the board molded in accordance with Example 2 of the present invention and a photograph (b) showing the results of the quasi-non-flammable experiment in the quasi-non-flammable board on the market. As a result, it was confirmed that the board of Example 2 of (a) the drawing showed improved semi-non-flammable performance compared to the quasi-non-flaming board sold in the market of (b). It is inferred that this is the result that the density and the adhesion are improved according to the technique of the present invention, and that the flame retardant layer is well formed so that the foam particles do not come into contact with the external gas.

In particular, the board molded according to Example 3 of the present invention is below the reference value in the combustion performance test-heat release rate (cone calorimeter method), smoke generation rate (dynamic measurement), mass reduction rate measured under KS F ISO 5660-1: 2015. Satisfactory result was confirmed.

For reference, although commercially available semi-non-combustible boards are products that have been certified for performance, combustion performance tests measured under KS F ISO 5660-1: 2015-thermal emission rate (cone calorimeter method), smoke generation rate (dynamic measurement), mass reduction rate In all, it was confirmed that all of the criteria were not satisfied.

Experimental Example 4

The compressive strength of the board of Example 2 was measured by requesting the Korea Institute of Construction Living Environment. As a result of the measurement according to KS M 3808: 2011, it was confirmed that the board formed according to Example 2 had a compressive strength of 6N / cm 3 and a flexural fatigue strength of 20N.

Experimental Example 5

After applying the board manufactured in Example 2 as a heat insulating material on the outer wall of the building, and after 6 months, after peeling off and measuring the welding strength and quasi-incombustibility, it was confirmed that the same welding strength and quasi-non-combustibility results as in the first production It was.

Experimental Example 6

Peel strength was measured with the sandwich panel of Example 4 and the sandwich panel marketed commercially. Specifically, in the sandwich panel manufactured, the board, the upper iron plate, and the lower iron plate were peeled by hand, and the cross section of the separated iron plate was visually confirmed.

FIG. 7 is a photograph of a flame retardant bead remaining on a metal plate when a sandwich panel is molded according to an embodiment of the present invention, and a picture of a flame retardant bead remaining on a metal plate when a sandwich panel is commercially available. to be.

Referring to (a) of FIG. 7, it was confirmed that almost no flame retardant beads remained on the metal plate, while (b) it was confirmed that the flame retardant beads adhered to almost the entire surface of the metal plate. It is inferred that this is the result of improved density and fusion in accordance with the techniques of the present invention.

Reference Example 1

Except for forming the flame retardant layer 13 as the raw material of the flame retardant bead in <Example 1>, the same procedure as in Example 1 was repeated to produce foamed particles 11.

As a result, the flame retardant layer 13 was not formed in the outermost portion of the flame retardant beads with a sufficiently even thickness, and the part where the foamed particles 11 were exposed as it could be observed with the naked eye.

Through the above embodiment, it was confirmed that the fusion force of the board of the present invention is strengthened based on the above-mentioned reasons, that is, the composition and structure of the adhesive layer and the flame retardant layer, and the foaming degree of the foam particles is increased.

Features, structures, effects, and the like illustrated in the above-described embodiments may be combined or modified with respect to other embodiments by those skilled in the art to which the embodiments belong. Therefore, contents related to such combinations and modifications should be construed as being included in the scope of the present invention.

10 flame retardant beads
11 foam particles
12 adhesive layer
13 flame retardant layers
100 Manufacturing Equipment
110 foamer
120 dryer
121 Dry Body
122 Heating means for bottom of dry body
123 housing
124 air stack
125 air conditioner
130, 160 ripening machine
140 coating machine
141 Stirring Tank
142 glue first tank
143 drying tank
144 Flame Retardant Post Tank
145 transfer tank
146 separate glue supply tank
150 Temperature Gradient Control Means
151 Measuring section
153 control unit
155 heater
170 board molding machine
180 Sandwich Panel Forming Machine
181 boards
182a upper metal plate
182b bottom metal plate
183a Adhesive Top Nozzle
183b Glue Bottom Nozzle
184a upper heating wire
184b bottom heating wire
185a heating means
185b bottom heating means

Claims (16)

Foaming step of producing foamed particles by foaming the foamed styrene raw material;
A drying step of drying the foamed particles after the foaming step;
An adhesive coating step of applying an expandable first adhesive to an outer surface of the foam particles after the drying step to provide an adhesive layer;
A flame retardant coating step of preparing a flame retardant bead having a flame retardant layer formed by applying a flame retardant on the adhesive layer of the foam particles after the adhesive coating step;
A maturation step of aging the flame retardant beads to which the flame retardant is applied;
A molding step of forming the board by molding the flame retardant beads after the aging step; And
And a board drying step of drying the molded board in the forming step,
The method of manufacturing a flame retardant board to control the temperature of the external space in which the device is installed in order to reduce the internal temperature gradient of the devices in which the flame retardant beads are manufactured in the flame retardant coating step. The method of claim 1,
The adhesive coating step is a method of manufacturing a flame-retardant board after the drying step to apply the first adhesive to 1 to 10 parts by weight based on 100 parts by weight of the foam particles on the outer surface of the foam particles. The method of claim 2,
The flame retardant coating step,
A method of manufacturing a flame retardant board for applying a mixed solution of the flame retardant and the second adhesive is mixed. The method of claim 3,
The flame retardant coating step is a method of manufacturing a flame retardant board to apply a mixture of the second adhesive and the flame retardant 100 to 250 parts by weight based on 100 parts by weight of the foam particles. The method of claim 4, wherein
The foamed styrene raw material is a foaming ratio of 70 to 150 times the manufacturing method of the flame retardant board. The method of claim 5,
The first adhesive and the second adhesive is a foamed adhesive manufacturing method of the flame-retardant board. The method of claim 6,
The first adhesive and the second adhesive is a flame-retardant board manufacturing method of foaming in the flame retardant coating step, the aging step, the molding step and the board drying step. The method of claim 7, wherein
The drying step is a method of manufacturing a flame retardant board that is performed while controlling the temperature gradient between the central temperature and the upper temperature inside the main body by blocking the upper outside air of the main body is drying. The method of claim 8,
The drying step is a method of manufacturing a flame-retardant board that is performed while blowing the hot air from the lower portion of the main body is drying is performed while heating the bottom of the main body. The method of claim 9,
The flame retardant coating step
Mixing the flame retardant raw materials;
A coating step of coating the flame retardant mixed in the mixing step by stirring for 100 to 300 seconds at a temperature exceeding 40 ° C. or less than 60 ° C .;
A post-coating drying step of drying by stirring for 100 to 500 seconds at a temperature below 50 ° C. after the coating step; And a transfer step of transporting while drying over 100 to 300 seconds at a temperature of less than 50 ° C. after the drying step after the coating. The method of claim 10,
The aging step is a method of producing a flame-retardant board for aging for 2-5 hours at 40 ℃. The method of claim 11,
The molding step is a method of manufacturing a flame retardant board to be carried out by vacuum cooling for 40 to 50 seconds after the first step of 10 to 20 seconds and the two-step steam treatment of 1 to 5 seconds under the steam pressure of 1 ~ 5kg / cm. The method of claim 11,
The molded board is a method of producing a flame-retardant board to be aged for at least 24 hours at 20 ℃ or more after drying for 1 to 3 hours at 40 ~ 50 ℃. The method of claim 7, wherein
When the average diameter after the flame retardant coating step of the flame retardant bead is s1, and the average diameter after the board drying step of the flame retardant bead is s2, s2 ≥ s1 + s1 × 0.005 manufacturing method of a flame retardant board. A flame retardant board made by the method of claim 1. The sandwich panel which adhere | attached the metal plate on both surfaces of the flame-retardant board manufactured by the method of any one of Claims 1-14.

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