JP2001090318A - Building plate, and its manufacturing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a building plate having a structure in which a back sealer application process and a drying process are dispensed with, and the waterproof function of a sealer layer which have been formed on a reverse side of the building plate can be effectively demonstrated, and capable of excellently protecting the reverse side of the building plate even when a nail is driven therein. SOLUTION: In a building plate 1, a PET foamed layer 4 and a recycled PET sheet layer 5 are lined on a cement substrate 2 so that the recycled PET sheet layer 5 is disposed on the outer side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a building board suitable for use as an outer wall of a building, and more particularly to a building board having a rear surface having an improved waterproof function and a manufacturing apparatus therefor.

[0002]

2. Description of the Related Art Conventionally, at the beginning of a building board coating process, back sealer coating is performed to impart a certain degree of waterproofness to the back surface of a board of a building board. The coating amount in that case is about 45 to 55 g / m ² in a wet state, and the thickness of the dried sealer coating is about 10 to 20 μm. Since the sealer is adhered to the back surface of the plate, the film thickness is reduced by the amount of the sealer impregnated inside the porous plate. Here, the sealer refers to a paint used to fill the pores of the surface to be coated which is porous and large in absorbency, and a colorless and transparent acrylic urethane-based paint is often used in general. .

[0003]

By the way, the back surface of a cement substrate (which is a plate before painting) manufactured on a substrate manufacturing line is formed almost flat, There are fine irregularities and a large number of voids, and the density in the thickness direction of the plate is not always uniform. Therefore, in terms of sealer permeability in the back sealer coating step in the continuous coating step of the building board,
It is unavoidable that a problem of partial application unevenness is inevitable. In such a case, the desired waterproof effect cannot be sufficiently exhibited.

On the other hand, increasing the amount of sealer applied to the back of a building board, which is not directly visible in normal use, greatly increases the cost of the product. Absent. Originally, the function that the sealer layer should exhibit is that, unlike the surface coating layer, it is not the part that is directly exposed to rainwater. At present it is being painted. For this reason, little attention has been paid to other physical properties such as scratching strength, and the strength has never been a strong film.

[0005] Due to this, there is a sufficient risk that a scratch or the like will occur during distribution or on the construction site. If a scratch or the like occurs once,
Infiltration of water from that part is inevitable anymore. In addition, there is no need to occasionally cause a catastrophic failure such as a real part being chipped due to a certain impact.

In view of this situation, the present applicant has previously filed an application for a “building board, a manufacturing apparatus thereof, and a pre-foamed plastic” in which a foamed plastic sheet is lined with a cement substrate cloth (Japanese Patent Application No. 11-110). 242022).
In order to line this building board with foamed plastic on the cement substrate fabric, first, while foaming polyethylene on the recycled PET nonwoven fabric, the foamed polyethylene is laminated on the cement substrate fabric together with the recycled PET nonwoven fabric,
Thereafter, the recycled PET non-woven fabric is manufactured through a step of separating the non-woven fabric. For this reason, an extra step of detaching the recycled PET non-woven fabric is required. Further, if this step fails, the surface of the backed foamed plastic is destroyed, or in the worst case, the backed foamed plastic is peeled off. I was afraid.

[0007] In view of the above problems, the present invention eliminates the back sealer application and the subsequent drying step, and effectively exerts the waterproof function of the sealer layer conventionally formed on the back of the building board. It is an object of the present invention to provide a building board and a manufacturing apparatus thereof that can be manufactured easily and reliably.

[0008]

According to the construction board of the present invention, a foamed plastic and a non-foamed plastic are lined on a cement substrate cloth so that the non-foamed plastic is on the outside. In addition, since the foamed plastic contains polyethylene as a main component, a building board having particularly excellent low-temperature properties, flexibility, and toughness can be provided.

Further, the thickness of the foamed plastic is
When the thickness is 0.5 to 3.0 mm, it is preferable in terms of strength and shape scale. Further, the non-foamed plastic is
By using PET (polyethylene terephthalate) as a main component, it is possible to provide a low-cost, harmless building board particularly excellent in low-temperature properties, flexibility, and toughness.

[0010] Further, the building board manufacturing apparatus of the present invention allows the foamed plastic and the non-foamed plastic to be on the outside during the process of foam-forming the foamed plastic sheet on the non-foamed plastic sheet. And a backing means for backing the cement substrate cloth. In addition, the backing means can use the plate temperature of the carry-out building board for foaming the foamed plastic by backing the building board after the clear coating, and there is no step of heating to a high temperature thereafter. Therefore, the backing plastic sheet is not damaged.

[0011]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG.
1 is a diagram showing a partial cross-sectional structure of a building board according to an embodiment of the present invention. The building board 1 has a surface coating layer 3 on the surface of a cement base material 2, and a foamed plastic, preferably a PE (polyethylene) foamed layer 4, on the back side, facing outward from the back side of the board. , Non-foamed plastic, preferably
Recycled PET (polyethylene terephthalate) sheet layer 5
It has a structure backed by. It should be noted that when viewed in detail, the layers are not clearly distinguished from each other, but are in a state in which adjacent layer components are fused, and the PE impregnated layer 6 in which the foamed PE is impregnated in the cement base material 2, And foam P
A mixed layer 7 in which E and recycled PET are mixed may exist.

The cement base 2 is prepared by pressing and curing a raw material mat formed by forming or extruding a raw slurry on a porous support. Raw material slurries include, for example, Portland cement, blast furnace cement in which blast furnace slag is mixed with Portland cement, fly ash cement in which fly ash is mixed, silica cement in which silica materials such as volcanic ash, silica fume, and clay are mixed, alumina cement, blast furnace slag And cement-based inorganic hydraulic materials such as wood flour, wood wool, wood chips, wood fiber, wood pulp, softwood pulp, hardwood pulp, wood fiber bundles, waste paper pulp, hemp fiber, bacas, fir, rice straw, bamboo fiber, etc. Wood reinforcement and, if desired, acceleration of hardening of aggregates such as pearlite, shirasu balloon, expanded shale, expanded clay, calcined diatomaceous earth, fly ash, coal ash, crushed foam concrete and alkali metal silicate Agents, waxes, waxes, paraffins, surfactants, waterproofing agents such as silicone, and water repellents The dispersed in water usually 5 solids
It is adjusted to about 20% by weight.

The PE foamed layer 4 preferably uses a resin foamed by a normal pressure foaming method. Linear polyethylene is preferred because of its excellent chemical resistance. Non-crosslinked ones are preferred because they can be regenerated. By adjusting the material density, a wide variety of PE foam layers 4 from a soft type to a semi-hard type can be manufactured. Further, by adjusting the amount of the foaming agent kneaded, the P of any thickness can be adjusted.
The E foam layer 4 can be formed. The thickness of the PE foam layer 4 is
0.5 to 3.0 mm is preferred. If the thickness is less than 0.5 mm, a problem occurs in terms of strength, and the function of waterproofness cannot be sufficiently exhibited. Conversely, 3.
When the thickness exceeds 0 mm, the building board as a whole becomes unnecessarily bulky and its commercial value is reduced.

In the normal pressure foaming method, for example, an extruder is prepared by mixing a thermally decomposable foaming agent such as azodicarbonamide with a foaming olefin resin composition such as polyethylene or polypropylene at a temperature at which the foaming agent is not decomposed. The mixture is melt-kneaded with a roll or the like, and the kneaded material is preformed into a sheet or other appropriate shape by extrusion molding, press molding, or other appropriate means, and the preformed product is introduced into a heating chamber, and the decomposition temperature of the foaming agent is increased. This is a method of foaming the resin at normal pressure by heating. In addition, known foaming methods such as an extrusion foaming method and a pressure foaming method can be applied.

In the extrusion foaming method, for example, a resin composition for foaming is melt-kneaded by an extruder, and an inflatable liquid such as dichlorotetrafluoroethane is injected from a foaming agent injection port provided in the kneading section of the extruder. A foaming agent or an inert gas-type foaming agent such as carbon dioxide is pressed into a molten resin, or a mixture obtained by previously mixing a thermally decomposable foaming agent such as azodicarbonamide with the above resin composition for foaming is used as an extruder. Melt-kneaded at
This is a method of extruding this while foaming it into an appropriate shape from an extrusion die.

In the pressure foaming method, for example, a resin composition for foaming is melt-kneaded with an extruder or a roll, and the kneaded material is preliminarily formed into a sheet or other appropriate shape by extrusion molding, press molding or other appropriate means. The preform is placed in a pressure chamber such as an autoclave and heated under pressure, and an inflatable liquid foaming agent such as dichlorotetrafluoroethane or an inert gas foaming agent such as carbon dioxide is charged into the preform. It is a method of impregnating from the surface and then foaming by releasing the pressure in the pressure chamber.

The foaming agent used in each of the above foaming methods is also not particularly limited, and may be a low-boiling organic solvent, an inflatable liquid foaming agent such as a swelling agent, an inert gas foaming agent, or a thermal decomposition type foaming agent. Any blowing agent, such as a blowing agent, can be used. As the recycled PET sheet layer 5, a plastic sheet that does not deform as a whole even when the temperature becomes higher than the temperature at which the PE foam layer 4 foams is used. There is no problem if the mixture layer 7 is slightly softened to form the mixed layer 7 in which the foamed PE and the recycled PET are mixed.

FIG. 2 is a top view for explaining the laminate sheet 11. The laminated sheet 11 is for backing the cement base material 2, and is formed, for example, on the surface of a long heat-resistant recycled PET sheet (nonwoven fabric or woven fabric) 12 to be narrower than the recycled PET sheet 12. The unfoamed PE laminate layer 13 is coated wider than the cement base material 2.

FIG. 3 is a flowchart for explaining a laminate sheet backing process of the building board manufacturing apparatus according to the present embodiment. The process within the broken line is the process according to the present invention and is inserted into the conventional process. Except that the sealer is not lined, from the drying process after clear coating of a normal building board manufacturing apparatus (step S101), the work plate a that comes out with the surface (pattern surface) facing up is inverted. From (Step S102), the supplied plate a is supplied and subjected to laminating (Step S103). On the other hand, a laminate sheet 11 coated with an unfoamed PE laminate layer 13 is supplied (step S104), and the laminate sheet 11 is subjected to a first-stage heat treatment so that the PE laminate layer 13 is heated, melted, and foamed. (Step S105), the laminate sheet 11 and the work plate a are laminated (Step S106), rapidly cooled (Step S107), and the work plate a is carried out and inverted again (Step S108). Cooling (step S109), which is a process of the ordinary building board manufacturing apparatus, cuts out or trims the excess laminate sheet 11 that protrudes from the contour boundary of the work board a (step S110), and inspects the board (step S11).
1), and proceed to shipping (step S112).

FIG. 4 is a diagram for explaining the processing principle of the building board manufacturing apparatus according to the present embodiment. FIG. 5 is a diagram illustrating a configuration of a corresponding concrete building board manufacturing apparatus. The inverted plate a is placed on the carry-in conveyor 31 with its longitudinal direction as the traveling direction A, and is conveyed to the laminating unit.

FIG. 6 is a view for explaining the building board 1, the carry-in conveyor 31, and the belt conveyor serving as the carry-out conveyor according to the present embodiment. FIG. 6A is a plan view and a side view as viewed from the back side of the building board 1. Building board 1 is male part 5
1 and the female part 52, and the plate surface pattern part 53 has a large irregularity in recent years in terms of design. Therefore, in place of a normal transport roller, a belt conveyor is used here. Shall be used. The plate a to be processed is shown in FIG.
(b) and FIG. 6 (c), the side view and the plan view of which are sandwiched between a number of guide blocks 56 on both sides provided by fixing pins 55 on a belt 54 of a belt conveyor, and
Is loaded into the laminating unit with the back side of the unit facing upward.

On the other hand, the laminate sheet 11 wound into a roll is fed out of a sheet roll 21 and then, with the recycled PET sheet 12 on the upper side and the PE laminate layer 13 on the lower side, the surface of the PE laminate layer 13 Is heated from the lower side by the far-infrared heater 22 in the first stage, and the PE laminate layer 13 starts melting. When reaching the position immediately before the laminating part, the PE laminate layer 13 starts foaming. The sheet surface temperature at this time is
For example, it is 175 ° C. The carry-in of the laminate sheet 11 into the laminating section is performed by a feed roll 32, and the carry-in angle is adjusted by a guide roll with an adjuster (preferably made of a silicone rubber roll) 33.

In the laminating section, first, the work-to-be-processed a that has been carried in is subjected to a feed heating press working. In this method, the plate a to be processed is heated while being transported by the heating press roll 34 and the lower backup sponge roll 35 disposed opposite to the heating press roll 34. The backup sponge roll 35 is made of a heat-insulating sponge roll (having elasticity) and absorbs the uneven shape of the surface of the plate a to be processed so that the pattern is not crushed. Do not let out the heat. The sheet is further heated to, for example, 200 ° C. by this heating.

During the feed heat press working, the laminate sheet 11 partially impregnates the face layer on the back surface of the work piece a to form the PE impregnated layer 6 (see FIG. 1). This impregnation greatly improves the adhesive strength of the sheet. During this time, the foaming is progressing microscopically, but is macroscopically suppressed due to the pressing pressure. That is, the PE foam layer 4 does not become unnecessarily thick.

After finishing the press working, continue with PE
The foam sheet is guided forward by the auxiliary heating Teflon-coated endless belt 36 disposed above the work plate a with a clearance corresponding to the design thickness of the foam layer 4. Teflon coated endless belt for auxiliary heating 3
In No. 6, auxiliary heating is performed by abutting the heat roll 37 from the back surface of the belt so that the sheet surface temperature is maintained at, for example, about 185 ° C., during which PE foaming is completed.

Further, after the feed heating press working is completed, the work plate a is immediately taken out of the unloading conveyor 38 running thereunder.
It is movably mounted on the upper side and transported forward. The feeding roll 32, the heating press roll 34, the Teflon-coated endless belt 36 for auxiliary heating, the unloading conveyor 38
And are operated synchronously.

A heater retreat mechanism 39 is provided so that when the rear end of the plate a passes the feed roll 32, the far-infrared heater 22 is turned off and retracted to a predetermined position. The feed roll 32
The sheet gripping roll (for example, a silicone rubber roll) 40 retracted to a lower position opposite to the upper side rises and comes into contact with the feed roll 32, so that the laminated sheet 11
Is gripped by these two rolls 32, 40,
A sheet gripping roll retracting mechanism 41 is provided.

At the stage when the laminate sheet 11 is gripped, the sheet is cut at a high speed by the laser knife 42 at the laser receiving stage 43 slightly in front of the sheet (by the operation of reciprocating across the sheet portion). The laminate sheet 11 is cut slightly obliquely. Here, the processed plate a after the lamination is completely independent.

The processed plate a, which has become an independent body, has been conveyed to the next cooling zone by the unloading conveyor 38. In the cooling zone, a cooling process is performed in which cold air is blown to the back surface of the sheet and duct suction is performed from both sides. Thereafter, the plate a to be processed is turned over again, and is placed on a normal transport roller or a chain conveyor with the plate surface pattern portion 53 facing upward, carried out of the laminating system, and subjected to the next processing. Move to the process.

FIG. 7 is a diagram showing an entire configuration of a building board manufacturing apparatus according to an embodiment of the present invention. The main controller 100 controls the following units. First, a sheet for measuring the surface temperature of the laminated sheet 11 heated by the far-infrared heater 22 by controlling the heater retreat mechanism 39 by detecting the passage of the plate a to be processed by the passage detection switches S1 and S2 at the front end of the plate. A far-infrared heater controller 62 that controls heating of the far-infrared heater 22 by the surface thermometer 61 is controlled. The heating of the heating press roll 34 is controlled by a roll surface thermometer 63 for measuring the surface temperature of the heating press roll 34 and a sheet surface thermometer 64 for measuring the surface temperature of the laminate sheet 11 heated by the heating press roll 34. The heating press roll temperature controller 65 is controlled. Heat roll 3
The heat roll controller 67 for heating the back of the Teflon-coated endless belt, which controls the heating of the heat roll 37, is controlled by a sheet surface thermometer 66 for measuring the surface temperature of the laminated sheet 11 heated by 7.
The above is the heating control system. The transport controller 68 controls the rotation of the carry-in conveyor 31, the carry-out conveyor 38, the heating press roll 34, the backup sponge roll 35, and the auxiliary heating Teflon-coated endless belt 36 in synchronization. This is a plate transport control system. It controls a press roll pressure adjustment 69 for adjusting the press pressure of the heating press roll 34, a sheet gripping roll retreat mechanism 41, a sheet feed motor 70 for rotating the sheet roll 21, and a sheet supply controller 71 for controlling the feed roll 32. Passage detection switch S3 at the rear end of the plate
The laser knife controller controls the laser knife reciprocating drive motor 72 for reciprocating the laser knife 42 and the laser generator 73 for generating the laser by detecting that the plate a to be processed has been completely carried into the laminating portion. 74 is controlled. These are sheet supply systems.

FIG. 8 is a flowchart illustrating the operation of the building board manufacturing apparatus according to the present embodiment. First, the laminate sheet 11 is pulled out from the sheet roll 21 by an operator, and with the front end thereof placed on the laser receiving stage 43, the feed roll 32 and the sheet gripping roll 40 abutting on the feed roll 32 are used. It is in a gripped state. The penetration angle of the laminate sheet 11 is adjusted by moving the guide roll 33 with an adjuster forward and backward.

Further, the far-infrared heater 22 is provided by:
The installation angle is adjusted according to the adjustment of the penetration angle of the laminate sheet 11, and the standby state is established in a state in which the laminate sheet 11 faces the front side of the laminate sheet 11 and approaches a predetermined distance. (Angle adjustment and distance adjustment mechanisms are not shown). Further, rotation of the heating press roll 34 and the Teflon-coated endless belt 36 for auxiliary heating and control of heating are started.

Then, the operation of the carry-in conveyor 31 and the carry-out conveyor 38 in the plate transfer control system is started. Thus,
From the standby state in which the laminate sheet 11 can be supplied and is stopped (step S1), the carry-in conveyor 31
When the detection switch S1 detects that the front end of the plate a has passed the upper predetermined position (step S2), the far infrared heater 22 is turned on (step S3).

At the same time or slightly later, the rotation of the sheet feed motor 70 and the feed roll 32 is started (step S4). The tip of the laminate sheet 11 is a curved guide 44 provided slightly in front of the laser receiving stage 43.
Is guided to the collection basket 45 below, and the unnecessary laminate sheet 11 at the start of processing is collected. When the detection switch S2 detects that the front end of the plate a has passed the predetermined front position near the front end of the carry-in conveyor 31 (step S5), the sheet gripping roll 40 is retracted to a predetermined lower position. (Step S6).

At the same time, the laser knife 42 is driven to the opposing position to cut the sheet (step S7). (First Front End Cut) The plate a to be processed is further pushed forward by the carry-in conveyor 31, and then is sent forward by being held by the heating press roll 34 and the backup sponge roll 35. . During this time, foam lamination is performed.

When the detection switch S2 detects that the rear end of the work plate a has passed the same predetermined position near the front end of the carry-in conveyor 31 (step S8), the far infrared heater 22 is turned off. At the same time (step S
9), the far-infrared heater 22 is retracted to a predetermined retract position (step S10). When the detection switch S3 detects that the rear end of the workpiece a has passed a predetermined position just before the heating press roll 34 (step S3).
11) Run the laser knife 42 to the original position and cut the laminate sheet 11 (step S12). (1
Cut the rear end of the sheet)

The rotation of the sheet feed motor 70 and the feed roll 32 is stopped (step S13). At the same time, the sheet gripping roll 40 at the evacuation position is raised and brought into contact with the feed roll 32 to grip the laminate sheet 11 (Step S14).

During this time, if there is no abnormality (step S1)
5), the processed plate a after the lamination process is moved forward by the unloading conveyor 38, and proceeds to the next processing step. If there is an abnormality, the main controller 10
0 is notified of this (step S16), a stop process is executed, and the flow ends (step S17). Note that the present invention is not limited to the above embodiment.

[0039]

As described above, according to the present invention, (1) because water absorption from the back of the building board is effectively prevented,
The dimensional change of the entire plate is reduced. (2). Since the intrusion of CO ₂ from the back of the building board is considerably prevented, carbonation and neutralization of the cement board are prevented. (3). Since the absorption of chlorine ions from the inside is prevented by preventing water absorption from the back of the building board, oxidation (rust generation) of iron is prevented when fastening to the steel frame base etc. .

(4) Since the film strength (tear strength, rupture strength, etc.) is higher than in the case of sealer coating, the occurrence of scratches, cracks and chips (particularly, real parts) is suppressed. (5) Since the application step of the back sealer and the subsequent drying operation are eliminated, the energy cost is greatly reduced, and the total coating cost can be significantly reduced. (6). The construction method in which the building board is fastened to the steel frame base set prevents the squeaking noise of the building board.

(7) In the construction method in which a nail (or a screw) is driven in from the surface of the building board and fastened, the vicinity of the protruding portion of the nail is protected by the foamed plastic having a high elasticity of closed cells. It is possible to block to some extent. As a result, it is possible to much more effectively prevent rainwater from flowing to the back surface of the board. (8) .Because foam plastic is formed on the back,
A certain degree of shock absorption is exhibited, and the phenomenon of fine cracking even when an external force is applied is considerably reduced. (9) Since the foamed plastic is lined with the foamed plastic, a product having considerably improved strength can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing a partial cross-sectional structure of a building board according to an embodiment of the present invention.

FIG. 2 is a top view illustrating a laminate sheet used in the present embodiment.

FIG. 3 is a flowchart illustrating a laminate sheet backing process of the building board manufacturing apparatus according to the present embodiment.

FIG. 4 is a diagram illustrating a processing principle of the building board manufacturing apparatus according to the present embodiment.

FIG. 5 is a diagram showing a configuration of a building board manufacturing apparatus according to the present embodiment.

FIG. 6 is a diagram illustrating a building board and a belt conveyor according to the present embodiment.

FIG. 7 is a diagram illustrating an overall configuration of a building board manufacturing apparatus according to the present embodiment.

FIG. 8 is a flowchart illustrating the operation of the building board manufacturing apparatus according to the present embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Building board 2 Cement base material 3 Surface coating layer 4 PE foam layer 5 Recycled PET sheet layer 6 PE impregnated layer 7 Mixed layer 11 Laminated sheet 12 Recycled PET sheet 13 PE laminated layer 21 Sheet roll 22 Far infrared heater 31 Carry in conveyor 32 Feeding roll 33 Guide roll with adjuster 34 Heating press roll 35 Backup sponge roll 36 Teflon coated endless belt for auxiliary heating 37 Heat roll 38 Carry-out conveyor 39 Heater retreat mechanism 40 Sheet gripping roll 41 Sheet gripping roll retracting mechanism 42 Laser knife 43 Laser receiving stage 44 Curved guide 45 Collection basket 51 Male part 52 Female part 53 Plate surface pattern 54 Belt 55 Fixing pin 56 Guide block 61 Sheet surface thermometer 62 Far infrared heating Controller 63 Roll surface thermometer 64 Sheet surface thermometer 65 Heating press roll temperature controller 66 Sheet surface thermometer 67 Teflon coated endless belt Backside heating heat roll controller 68 Transfer controller 69 Press roll pressure adjustment 70 Sheet feed motor 71 Sheet supply controller 72 Laser knife reciprocating drive motor 73 Laser generator 74 Laser knife controller 100 Main controller a Work plate S1, S2, S3 Detection switch

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C04B 41/71 C04B 41/71 E04C 2/04 E04C 2/04 EF term (Reference) 2E110 AA14 AB04 AB22 BA03 BA13 BB03 BB04 BC02 CB02 DA02 DB22 DC17 EA06 GA03Z GA23W GA23X GA23Z GA24Z GA32X GB43X GB43Z 2E162 CA01 CA05 CA06 CA07 CD01 CD13 FA01 FA05 FA09 FC01 FC02 FC03 FC06 FC08 4F100 AE01A AK01B AK01E01 AK01B AK01B AK01B AK01B EH462 EJ17 EJ172 GB07 JD05 YY00B 4G028 FA01

Claims (6)

[Claims] 1. A building board characterized in that a foamed plastic and a non-foamed plastic are lined on a cement substrate cloth so that the non-foamed plastic is on the outside. 2. The building board according to claim 1, wherein the foamed plastic contains polyethylene as a main component. 3. The thickness of the foamed plastic is 0.5
The building board according to claim 1, wherein the thickness is from 3.0 mm to 3.0 mm. 4. The building board according to claim 1, wherein the non-foamed plastic contains PET (polyethylene terephthalate) as a main component. 5. The process of foam-forming a sheet of foamed plastic on a sheet of non-foamed plastic,
An apparatus for manufacturing a building board, comprising a backing means for backing a foamed plastic and a non-foamed plastic to a cement substrate cloth so that the non-foamed plastic is on the outside. 6. The building board manufacturing apparatus according to claim 5, wherein the backing means backs the building board after the clear coating.