JPH10231160A - Hard wood chip cement board and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To specify a wood amount of a hard wood chip cement board in the surface part and improve the surface property and nailing property of the board, by dropping a mixture consisting essentially of cement and wood chips into a forming chamber while blowing air thereto to classify the mixture and spraying and depositing the mixture onto a lower template. SOLUTION: A mixture consisting essentially of cement and wood chips is dropped onto a slant sieve 22. At the time, air is blown from an air discharge port 24 of a blowing duct 23 thereto to classify the mixture. Fine and light raw material is deposited on a lower template 11 on the upstream side and a coarse and heavy raw material is deposited on the middle stream side to provide deposites 13. Further, a mixture 14 having the same composition is carried to the downstream end part and dropped to a slant sieve 32. Air is blown to the mixture to classify the mixture and the coarse and heavy raw material is deposited on the lower template 11 on the middle stream side and fine and light raw material is deposited on the downstream side. As a result, the finest and lightest raw material is deposited on the uppermost face of the deposites 13 and dense surface part is obtained on the rear face. The air velocity is set to about 10-20m/sec so that wood amount of the surface part becomes 8-14wt.%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hard wood chip cement board excellent in nailing properties and smoothness and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, a hard wood chip cement board, which has been widely used as an exterior material and a base material, is obtained by pressing a mixture mainly composed of cement and wood chips and curing the mixture. Things. That is, cement,
The mixture obtained by mixing the raw materials such as wood chips and aggregates is dropped in a forming chamber, and the mixture is sprayed and deposited on a lower mold plate conveyed by a conveyor belt to obtain a sediment. The hard wood chip cement board was manufactured by placing and pressing the upper mold board and curing and curing.

In particular, when the mixture is dropped and sprayed,
When the mixture is blown and classified, fine and light raw materials are blown away and fall, while coarse and heavy raw materials fall nearby. For this reason, when wind is blown in the direction opposite to the transport direction, fine and light raw materials are first deposited on the upper surface of the lower die plate on the upstream side, and deposits in which coarse and heavy raw materials are sequentially deposited are obtained. As a result, a small piece of wood,
Aggregate and the like are deposited, and a hard wood chip cement board having excellent surface properties can be obtained.

[0004] However, according to the above-mentioned hard wood cement board, when the wind is blown strongly, the surface portion becomes too dense and becomes too hard, so that nailing work becomes difficult and cracks are easily generated. There is.

Conversely, if the wind is stopped or blown along the transport direction, coarse and heavy raw materials will be deposited on the upper surface of the lower mold plate, and the lowermost surface of the deposit, that is, the surface side, will be rough. Heavy wood chips and aggregates accumulate and become sparse. For this reason,
While the nailing operation is facilitated, there is a problem that the surface property is reduced and the surface strength is also weakened, so that it cannot be put to practical use.

SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide a hard wood chip cement board having nailing properties while maintaining surface properties suitable for an exterior material and a base material, and an object of the present invention. I do.

[0007]

In order to achieve the above-mentioned object, a hard wood chip cement board according to the present invention has a hard wood chip cement board mainly composed of cement and wood chips, and has a surface portion having a wood mass of 8 to 14 weight. %.

[0008] In a hard wood chip cement board having at least two layers consisting of a surface portion and an inner portion mainly composed of cement and wood chips, the mass of the wood of the surface portion is 8 to 10%.
14% by weight, the overall density is 0.7 to 1.3 g / cm ^3, and the density of the surface portion is + 0.0% higher than the density of the internal portion.
The configuration may be 5 to −0.1 g / cm ^{3 or} less.

Further, in order to achieve the above object, the method for producing a hard wood chip cement board according to the present invention drops a mixture mainly composed of cement and wood chips in a forming chamber, and simultaneously classifies the mixture by blowing air. A method of manufacturing a hard wood chip cement board which is scattered and deposited on a lower mold board conveyed by a conveying means to obtain a deposit, and then the upper mold board is placed on the deposit and pressed to cure and harden. The wood mass of the surface portion of the board is 8-14% by weight, the overall density is 0.7-1.3 g / cm ^3, and the density of the surface portion is + 0.05--0.
The process may be such that the speed of the air blown in the forming chamber is set to 10 to 20 m / sec so as to be within 1 g / cm ³ .

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. The cement is not particularly limited, and examples thereof include Portland cement, blast furnace cement, silica cement, fly ash cement, and alumina cement. Further, a siliceous material may be added to improve the reactivity. This includes, for example, quartz sand, quartzite powder, diatomaceous earth, silica fume, fly ash and the like.

In the hard wood chip cement board of the present invention, the cement is added in a range of 50% by weight to 92% by weight.

The type of the wood chip is not particularly limited, and for example, chips of cedar, pine and the like and crushed waste wood can be used alone or in combination.

[0013] The wood piece is preferably of a size that passes through a sieve having a mesh size of 4 mm. This is because if a piece of wood that cannot pass through a sieve having an opening of 4 mm is mixed, the portion becomes a weak point and the peel strength decreases. Preferably, the wood piece is a flat piece having an average thickness of 0.5 mm.

The wood chips are added in the range of 8 to 30% by weight,
In particular, the amount of wood chips added to the surface is 8 to 14% by weight.
It is preferred that If the amount of the wood chips is less than 8% by weight, the surface becomes too dense and becomes too hard, which makes nailing difficult, and becomes brittle, so that chipping or cracking is likely to occur at the time of nailing. On the other hand, when the content exceeds 14% by weight, the amount of wood chips becomes too large, the surface properties deteriorate, and the proportion of cement decreases. For this reason, the bonding force between the pieces of wood is weakened, the strength is reduced, and the nail holding force is reduced, so that chipping or cracking is likely to occur when nailing.

The surface portion is a surface layer having a thickness of 1/4 to 1/40 from the surface of a hard wood chip cement board having an overall thickness of 10 to 30 mm and a density of approximately the same. Part. The thickness dimension of 1/4 is usually 4
When it is formed in a forming chamber of the machine, it is the maximum thickness dimension capable of forming the entire surface of one layer to a wood mass of 8 to 14% by weight, specifically, about 2.5 to 7.5 mm. On the other hand, the thickness dimension of 1/40 is the minimum thickness dimension that can form the entire surface portion to a wood mass of 8 to 14% by weight when a thin layer is formed as a surface portion in a forming chamber. Is about 0.3 to 0.8 mm.

A lightweight aggregate may be added to reduce the specific gravity of the hard wood chip cement board. For example, perlite, shirasu balloon, glass balloon and the like can be mentioned, and these can be used alone or in combination. And it is added in the range of 0% by weight to 25% by weight.

Further, as an additive to be added to the hard wood chip cement board, for example, a hardening accelerator such as magnesium chloride, magnesium sulfate, calcium chloride, sodium aluminate, potassium aluminate, aluminum sulfate, water glass, vermiculite, Mineral powders such as bentonite, water repellents such as wax, paraffin and silicone, reinforcing materials such as synthetic resin emulsions, foamable thermoplastic plastic beads, plastic foams, and the like can be used as necessary.

As a method of obtaining the mixture by mixing the above-mentioned cement, wood chips, aggregate, additive and water, mixing may be performed using an existing machine, and the mixing method is not particularly limited.

The hard wood chip cement board of the present application preferably has an overall density in the range of 0.7 to 1.3 g / cm ³ . When the density is less than 0.7 g / cm ³ , sufficient strength as an outer wall material cannot be obtained, and the density is 1.3 g.
If it exceeds / cm ³ , it is too heavy and the workability deteriorates.

The density difference between the adjacent surface portion and the inner portion is that the density of the surface portion is +0.
It is preferable that the amount be in the range of 0.5 to -0.1 g / cm ³ . When the surface part becomes dense beyond + 0.05 / cm ³ ,
This is because, when the surface portion is easily peeled off and the internal portion is more dense than -0.1 g / cm ³ , the surface strength is weakened, the nailing property is deteriorated, and the surface property is also deteriorated.

Next, as a method of manufacturing the hard wood chip cement board of the present invention, for example, as shown in FIG. 1, there is a method of manufacturing using two first and second forming chambers 20 and 30. . That is, the conveyor belt 1
Two forming chambers 20, 30 are arranged above the lower mold plate 11 conveyed in the direction of arrow A by 0 so as to be line-symmetric along the conveyance direction.

The first forming chamber 20 comprises:
Below the downstream end of the supply conveyor belt 21, a sieve 22 is arranged at an angle. This sieve 22 is provided with an air discharge port 24 of a blowing duct 23 for blowing air in a direction opposite to the conveying direction.
And the air outlet 25.

On the other hand, the second forming chamber 30
Similarly to the first forming chamber 20, a sieve 32 is arranged to be inclined below the downstream end of the supply conveyor belt 31. The sieve 32 is disposed between an air discharge port 34 of an air duct 33 that blows air in the transport direction and an air discharge port 35.

Then, the conveyor belt 10 is moved in the direction indicated by the arrow A.
The lower mold plate 11 is conveyed in the direction of FIG. On the other hand, the supply conveyor belt 21 is driven, the mixture 12 described above is dropped, transported to the downstream end, and dropped on the inclined sieve 22. At this time, air is blown from the air discharge port 24 of the air blow duct 23, and the mixture 12 is sieved. For this reason, in the sieved mixture, the fine and light raw material is
1 and the coarse and heavy raw material is deposited on the lower mold plate 11 on the middle stream side, and a deposit 13 is obtained. As a result, the finest and lighter raw material is first deposited on the lowermost surface of the deposit 13 to form a dense surface portion.

Further, the second forming chamber 30
The mixture having the same composition as described above is dropped on the supply conveyor belt 31, and is conveyed to the downstream end, and is dropped on the inclined sieve 32. At this time, air is blown out from the air discharge port 34 of the air duct 33, and the mixture 12 is sieved. For this reason, the coarse and heavy raw material of the sieved mixture is the lower mold plate 1 on the middle stream side.
1 and fine and light raw material is deposited on the lower mold plate 11 on the downstream side. As a result, the finest and lightest raw material is deposited on the uppermost surface of the deposit 13, and the deposit 13 having a dense surface portion on the front and back surfaces is obtained.

The wood mass of the surface part is 8 to 14% by weight, and the density of the surface part is +0.05 more than the density of the inner part.
The speed at the air discharge port of the wind blown for sieving the mixture so as to be −0.1 g / cm ³ is:
The range is 10 to 20 m / sec. If the wind speed is less than 10 m / sec, coarse and heavy wood chips are distributed on the surface and the surface property is deteriorated. If the wind speed exceeds 20 m / sec, the surface becomes too dense and hard, and This is because it becomes difficult and easily peels off.

Next, an upper mold plate (not shown) provided with a surface pattern is placed on the upper surface of the deposit 13, and the deposit 13 is pressed and clamped by the upper mold plate and the lower mold plate 11, and then cured and cured. Thereby, a hard wood chip cement board is obtained.

Curing and curing is a process of curing cement to bond and integrate the wood pieces. Conventional methods such as steam curing and autoclave curing can be used.

The spraying and deposition of the mixture is not limited to the case where the wind is blown. For example, in the above-described manufacturing method, the wind is not blown between the first and second forming chambers, and the mixture is simply dropped. By forming at least one forming chamber that only scatters and deposits, thereby forming an inner part, a thick hard wood chip cement board may be formed. In addition, two types of mixtures each containing two types of wood chips having different sizes may be sequentially sprayed and deposited without blowing the wind to form a deposit having a surface portion and an internal portion having different densities. .

[0030]

【Example】

(Example 1) 92 parts by weight of commercially available Portland cement as cement, 8 parts by weight of a piece of wood passing through a 4 mm sieve as a piece of wood, 3 parts by weight of calcium chloride as a hardener,
40 parts by weight of water were mixed to obtain a mixture. Then, the mixture is sprayed and deposited on a lower mold plate to obtain a deposit, and the upper mold plate is placed thereon, pressed, cured and cured to obtain a specific gravity of only a surface portion having a thickness of 3 mm. 1 hard wood chip cement board was obtained.

(Example 2) Except that 86 parts by weight of the same cement as in Example 1 and 14 parts by weight of the same wood chip as in Example 1 were added, the same treatment was carried out as in Example 1 except for the above. The sample obtained was used as a sample.

(Comparative Example 1) Except that 94 parts by weight of the same cement as in Example 1 and 6 parts by weight of the same wood chip as in Example 1 were added, the same treatment was carried out as in Example 1 except that The sample obtained was used as a sample.

Comparative Example 2 The same treatment as in Example 1 was performed except that 80 parts by weight of the same cement as in Example 1 and 20 parts by weight of the same wood chip as in Example 1 were added. The sample obtained was used as a sample. For convenience of explanation, the composition and the like of the above samples are summarized in FIG.
Shown in

The surface properties and nailing properties of the sample obtained as described above were observed. The observation results are shown in FIG. However, the surface property was determined by visually observing the surface of the sample, based on whether or not the sample could be put to practical use as a commercial product. The nailing property was evaluated as “、” when the surface of the sample was not changed at all when the nail was driven into the surface of the sample at an angle of 60 °, and “○” when a small swelling occurred. age,
When a large swelling and small chipping occurred in the sample, the sample was marked with “△”, and when a large and deep chipping or cracking occurred in the sample, it was marked with “x”.

As is clear from the observation results of the surface properties, Examples 1 and 2 were inferior to Comparative Example 1, but were superior to Comparative Example 2, and it was found that there was no practical problem as a commercial product.

As is clear from the observation results of the nailing property,
It was found that both Examples 1 and 2 were superior to Comparative Examples 1 and 2 in nailing properties. As a result, it was found that Examples 1 and 2 were overall superior to Comparative Examples 1 and 2 as the exterior material and the base material. This proved that the amounts of wood chips and cement added in Examples 1 and 2 were appropriate for a hard wood chip cement board.

Example 3 As shown in FIG. 3 (a), 100 parts by weight of commercially available Portland cement as cement, 35 parts by weight of a piece of wood passing through a 4 mm sieve as a piece of wood, and 5 parts by weight of calcium chloride as a hardening agent And 60 parts by weight of water to obtain a mixture. A 30 mm thick deposit obtained by spraying and depositing this mixture on a lower mold plate was pressed with an upper mold plate, and then cured and cured to obtain a 13 mm thick hard wood chip cement plate, which was used as a sample.

In the apparatus for dispersing and depositing the mixture, third and fourth forming chambers for dispersing and depositing the mixture by simply dropping the mixture are disposed between the first and second forming chambers shown in FIG. It is. Then, in the first forming chamber, the wind speed is 19 m in the direction opposite to the transport direction.
/ Second wind, while classifying by blowing a wind of 19 m / sec along the transport direction in the second forming chamber along the transport direction, using the first, third, fourth, and second forming chambers sequentially. The mixture was sprinkled and deposited to obtain a deposit.

The sediment was pressed at a pressure of 20 kg / cm ² , cured at a temperature of 80 ° C. for 8 hours, and then indoors at 40 ° C. for 3 hours.
By leaving it to stand for a day, a hard wood chip cement board was obtained and used as a sample.

(Embodiment 4) The speed of the wind blown in the first and second forming chambers was 14 m /
A hard wood chip cement board was obtained and treated as a sample by treating in the same manner as in Example 3 except that the time was changed to seconds.

(Embodiment 5) The speed of the wind blown in the first and second forming chambers was 10 m /
A hard wood chip cement board was obtained and treated as a sample by treating in the same manner as in Example 3 except that the time was changed to seconds.

(Comparative Example 3) The speed of the wind blown in the first and second forming chambers was 21 m /
A hard wood chip cement board was obtained and treated as a sample by treating in the same manner as in Example 3 except that the time was changed to seconds.

(Comparative Example 4) A hard wood chip cement board was obtained and treated as a sample by treating it in the same manner as in Example 3 except that air was not blown in all the forming chambers. .

Then, for each of the samples of Examples 3, 4, 5 and Comparative Examples 3 and 4, the ratio of wood chips to cement at the surface portion, the density difference between the surface portion and the internal portion, the peel strength, the surface properties, and And nailing properties were measured and observed, respectively. Fig. 3 (b) shows the measurement and observation results.
Shown in

The ratio of wood chips to cement at the surface portion was determined by shaving a portion up to 0.5 mm from the surface,
It was determined by the weight loss rate at ° C. This was determined by calculation on the assumption that the weight loss rate of each mixed system at a predetermined temperature was constant, and the weight loss rate of the mixed system was linearly approximated.

The density difference between the surface portion and the inner portion is determined based on a density measurement graph obtained by measuring according to the depth, based on the difference between the density near 0.5 mm from the surface and the density near 3 mm from the surface. I asked.

The peel strength was measured according to a test method performed on JIS-A5905 fiberboard.

The surface properties and nailing properties were determined in Example 1 described above.
2 and Comparative Examples 1 and 2, experiments and observations were performed by the same method as that performed for Comparative Examples 1 and 2.

As is clear from FIG. 3B, all of Examples 3, 4 and 5 can be put to practical use in all of peel strength, surface properties and nailing properties, while Comparative Examples Sample No. 3 was found to have a low peel strength and could not be used practically. Further, it was found that all of Examples 3, 4, and 5 were superior to Comparative Example 4 in surface properties and nailing properties. Thereby, even in Examples 3, 4, and 5 where the surface portion is sparser than the inner portion,
It has been found that a desired hard wood chip cement board can be obtained if the amounts of cement and wood chips added to the surface portion are proper.

From Comparative Example 3, it was found that the peel strength was low even when the density difference between the surface portion and the inner portion was about 0.07 g / cm ³ .

In order to obtain desired surface properties and nailing properties, it is necessary that the weight ratio to cement is 8% by weight or more, and even if it is 11% by weight, the desired surface properties and nailing properties are obtained. It turned out that hitting property could be secured.

[0052]

As is clear from the above description, according to the hard wood chip cement board of the first aspect of the present invention, a hard wood cement board excellent in surface properties and nailing properties can be obtained. According to the second aspect, in addition to the above effects, a hard wood chip cement board in which delamination hardly occurs is obtained. According to claim 3, there is an effect that a hard wood chip cement board having the above-mentioned characteristics can be manufactured continuously and with high productivity.

[Brief description of the drawings]

FIG. 1 is a schematic front view showing a production process according to an embodiment of the present invention.

FIGS. 2A and 2B show Examples 1 and 2 and Comparative Examples 1 and 2, wherein FIG. 2A is a table showing component compositions, and FIG.
It is a chart showing an observation result.

FIGS. 3A and 3B show Examples 3, 4, and 5 and Comparative Examples 3 and 4, wherein FIG. 3A is a table showing component compositions, and FIG. 3B is a table showing manufacturing conditions and observation results.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Conveyor belt, 11 ... Lower mold plate, 12 ... Mixture, 13 ... Sediment, 20, 30 ... 1st, 2nd forming chamber, 21, 31 ... Supply conveyor belt, 2
2, 32 ... sieve, 23, 33 ... air duct, 24, 34 ...
Air outlets, 25, 35 ... air outlets.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI C04B 103: 14 111: 30 (72) Inventor Motoi Hikasa 1 Dai-Ichi Kogyo Co., Ltd.

Claims (3)

[Claims] 1. A hard wood chip cement board mainly composed of cement and wood chips, wherein the wood mass of the surface portion is 8 to 14% by weight. 2. A hard wood chip cement board comprising at least two layers consisting of a surface portion and an inner portion mainly composed of cement and wood chips, wherein said surface portion has a wood mass of 8 to 14% by weight and an overall density of 0.7. and ~1.3g / cm ^3, hard cemented chip board, characterized in that the density of the surface portion than said density of the inner part is within + 0.05~-0.1g / cm ^3. 3. A mixture mainly composed of cement and wood chips is dropped in a forming chamber, and at the same time, air is blown to classify the mixture, and the mixture is dispersed and deposited on a lower mold plate conveyed by a conveying means to obtain a sediment. A method of manufacturing a hard wood chip cement board which puts an upper mold plate on this sediment, presses and cures and hardens the hard wood chip board. 1.3 g / cm ³ and the density of the surface portion is +0.05 more than the density of the inner portion.
So that ~-0.1g / cm ³ less, method for producing a rigid cemented chip board, characterized in that the speed of the wind blowing in the forming chamber and 10 to 20 m / sec.