JP3355588B2 - Cellulose fiber-containing cement composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cement composition which is a raw material of building materials containing reinforcing fibers.

[0002]

2. Description of the Related Art Cement compositions obtained by mixing cement with aggregates such as sand and silica stone, further adding reinforcing fibers to the mixture, and mixing with water are widely used as building materials. Addition of the reinforcing fiber can alleviate local drying shrinkage of the composition after curing, not only suppress generation of cracks and the like, but also improve the strength of the cured product, particularly impact strength.

[0003] As one of the reinforcing fibers, there is an inorganic mineral asbestos which has a good compatibility with a cement material and a good fire resistance performance. The mortar containing asbestos has been applied with a trowel or sprayed with a specific device. Alternatively, a cement material containing asbestos is put into a mold and cured to form a plate-like substance or a substance of a specific shape, and then the construction is performed. In order to further improve the moldability of the cement material, water is added to a mixture of several tens of% of asbestos and aggregate to form a slurry, and the slurry is formed by a long round rope wire cylinder. There is a method in which a slight amount of water and a binder such as methylcellulose are added to the contained mixture of cement and aggregate, and the composition is extruded by a vacuum extruder.

In recent years, the effects of asbestos on carcinogenicity have been reported, and carbon fibers, synthetic organic fibers, inorganic fibers such as rock wool, and the like have been used as fibers instead of asbestos. However, none of the fibers are as familiar with cement as asbestos and have low heat resistance. For this reason, natural cellulose fiber is used as the fiber instead of asbestos. This is because natural cellulose fibers have no problem in hygiene, can maintain the necessary reinforcing effect up to the thermal decomposition temperature, and are biodegradable.

[0005] Natural cellulose fibers are broadly classified into wood pulp obtained from wood and linter pulp obtained from cotton seeds. Wood pulp fiber length is at most 2m
m, and the length distribution is not uniform. Since the elongated fibers are uniformly dispersed and the molded body is reinforced, fibers having a length of about 2 mm are not sufficient reinforcing fibers.

[0006] Although linter pulp has fibers of 10 mm or more, too long fibers may be entangled in a thread form and not dispersed when mixed with cement as a reinforcing material. The fiber length is cut to 5 to 10 mm so that the linter pulp can be dispersed well. At this time, the fiber length may be shortened more than necessary. Molded articles containing fibers that are too short cannot achieve the required strength. In order for the molded body to obtain a predetermined strength, it is necessary to reinforce the molded body with a fiber having an appropriate length.

In order to make the fiber length uniform, there is a method of producing regenerated cellulose fibers by spinning. Viscose rayon is one of the regenerated cellulose fibers. Viscose rayon is made from natural cellulose and NaOH solution.
This is a fiber spun by producing cellulose sodium xanthate by treating with S ₂ and blowing the sodium cellulose xanthogenate into dilute sulfuric acid. If the fiber is spun in this way, the diameter and length of the fiber can be easily adjusted in the spinning operation, and a reinforcing fiber having a suitable length and diameter can be efficiently produced. However, since viscose rayon is obtained by spinning cellulose into sodium xanthate, the crystallinity of the original cellulose is lost, the fiber density is reduced, and the strength as a reinforcing fiber is reduced.

[0008] The copper ammonia method is a method of spinning cellulose fibers by directly dissolving cellulose in a solvent without converting cellulose into a substance such as sodium xanthate. The copper ammonia method is a method in which linter pulp is dissolved in a Schweitzer reagent in which Cu (OH) ₂ is dissolved in NH ₃ water, and then spinning is performed in dilute sulfuric acid. However, the fiber obtained by the copper ammonia method has a problem that it is difficult to dispose of the fiber due to the toxicity of the Cu component contained in the Schweitzer reagent.

[0009]

DISCLOSURE OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and contains cellulose fiber which has sufficient strength as a reinforcing fiber, has good compatibility with cement, and is easy to dispose of. It is intended to provide a cement composition.

[0010]

Means for Solving the Problems The cement composition of the present invention made to achieve the above object is to prepare a polymer solution by dissolving cellulose in an amine oxide solvent.
This polymer solution is filtered, and the filtrate is spun in an aqueous solution, and contains cellulose fibers obtained as reinforcing fibers.

[0011] Examples of the cellulose include wood pulp and linter pulp. Amine oxide solvent is N
-Methylmorpholine-N-oxide or N-ethylmorpholine-N-oxide. These may be used alone or as a mixture.

The spinning is a solvent spinning, and is specifically performed as follows. Wood pulp or linter pulp that can be dissolved at a temperature of 50 ° C. or more
A polymer solution is prepared by dissolving at 0 to 150 ° C., and the polymer solution is filtered. The filtrate is injected into an aqueous solution by a nozzle or the like to regenerate the cellulose fibers. This cellulose fiber is washed and dried, and used as a reinforcing fiber.

Cellulose fibers obtained by solvent spinning have high crystallinity and excellent strength as reinforcing fibers.
A specific example is Tencel, a product manufactured and sold by Coatles. The diameter of the cellulose fiber is preferably 10 μm or less. In order to produce cellulose fibers of 10 μm or more, it is difficult to spin cellulose in an amine oxide solvent. The length of the fiber is preferably 3 to 10 mm. When it is 3 mm or less, the effect as a reinforcing fiber cannot be exhibited, and when it is 10 mm or more, it becomes difficult to mix with a cement material.
In order to obtain a fiber having a length of 3 to 10 mm, a fiber spun to an appropriate length may be cut.
It is operationally easier to cut to 10 mm, and then wash and dry.

The amount of the fiber added is 0.3 to the total composition.
~ 5% by weight is preferred. If the amount is less than 0.3% by weight, the strength of the molded article will be insufficient. If the content is 5% by weight or more, the fire resistance of the molded body decreases. The fibers are uniformly mixed with aggregate such as cement by a Henschel mixer or a high-speed mixer manufactured by Erich.

The cementitious molding composition containing cellulose fiber as a reinforcing fiber can be used in any of mold casting, papermaking and extrusion. Mold casting is a method in which a mortar to which reinforcing fibers are added is poured into a mold and molded. Papermaking is a method in which water is added to a mixture of reinforcing fibers and mortar, and the resulting slurry is formed by a wire cylinder and formed. Extrusion molding is a method in which water is added to a mixture of reinforcing fibers and mortar, dispersed and pressed in an extruder, and the mixture is continuously extruded to obtain a molded product. When steam curing is performed in an autoclave at a temperature of about 150 to 170 ° C. in order to obtain a high-strength molded body, the cellulose fiber becomes a reinforcing agent having sufficient strength without melting in any of the above methods. . Further, the mixture of fiber and cement may be applied with a trowel or sprayed with a machine.

Examples of the cement include ordinary portland cement, blast furnace cement, alumina cement, early-strength cement, and hydraulic cement. The content of cement in the composition is preferably 40% by weight or more. If it is less than 40% by weight, the strength required for the molded product cannot be obtained. As an aggregate other than cement, silica stone, silica stone powder, or silica fume may be added and used.

[0017]

Industrial Applicability The cement composition of the present invention is non-asbestos and is excellent in hygiene. When the cellulose fiber is mixed with a cement material and molded, the strength of the cellulose fiber is superior to that of viscose rayon, so that the molded article is suppressed from cracking. Since the toxic Cu component contained in the copper ammonia rayon does not exist in the cellulose fiber, disposal of the molded body is easy.

[0018]

Embodiments of the present invention will be described below in detail.

Example 1 Cellulose was dissolved in N-methylmorpholine-N-oxide (N-methylmorpholine-N-oxide hydrate manufactured by Nippon Emulsifier Co., Ltd.), and the solution was spun with a solvent to give a diameter of 10%.
A cellulose fiber having a size of not more than μm is produced. This cellulose fiber was cut into a length of 6 mm, and 70 parts by weight of cement (ordinary Portland cement) and 30 parts by weight of silica stone (manufactured by Tori Roof Co.) were added with the fiber parts shown in Table 1 by weight. Five types of samples (1) to (5) were prepared.

These samples were mixed with a Henschel mixer at 500 rpm for 3 minutes. Table 1 for each sample
Was added, and the mixture was stirred with an Erich mixer for 5 minutes to produce five types of slurries. The slurry was transferred to a 79 × 90 × 60 cm papermaking tank with agitate, and the parts by weight of coagulant shown in Table 1 were added. The coagulant to be added to (1) is a polyacrylamide coagulant KL-11B (manufactured by Hymo Co., Ltd.), (2),
The flocculant to be added to (3) is a polyacrylamide flocculant NR-101H (manufactured by Hymo Corporation), and the flocculant to be added to (4) is a polyacrylamide flocculant NR-11LH
(Manufactured by Haimo Co., Ltd.).

Next, the slurry was rotated at 10 m / min by a wire cylinder having a diameter of 500 and a length of 480 mm, and pressure was applied with a press roll of 50 kg / cm ^{2 to form} a paper having a thickness of 10 mm. The obtained molded body was cured at 45 ° C. and 100% humidity for 24 hours.
Autoclave curing was performed at 0 ° C. and 9 kg / cm ² for 8 hours. The mechanical strength and nail punching property were evaluated, and the results are shown in Table 1. Evaluation of mechanical strength was performed by measuring impact strength, curing time, bending strength, and compression strength.

The impact strength was measured by a Charpy impact test according to JIS K6911. The Charpy impact test is a test in which an impact is applied only once to the back surface of the cut portion of the molded body to break the molded body and measure the impact strength.

The curing time was set at 45 ° C. and a relative humidity of 1
After curing at 00%, the time is such that even if the surface of the molded body is rubbed with a B pencil, it will not be damaged.

The bending strength is determined by applying a load to the test piece,
It is calculated from the relationship between the deflection of the test piece caused by the load and the load.

The compressive strength is the maximum load per unit area that the specimen can withstand before being compressed and crushed.

The nailing performance was measured at 45 ° C. and a relative humidity of 1
After curing at 00% for 24 hours, 170 ° C, 9kg
/ Cm ² for 8 hours, and a nail of 2 mm in diameter was punched with a cannula to evaluate whether or not the molded article was cracked or not.

Comparative Example 1 70 parts by weight of asbestos 6D-3 cement and 30 parts of silica stone
The composition shown in Table 1 was added to the parts by weight, and the paper was formed in the same manner as in Example 1. Table 1 shows the evaluation results of the obtained molded bodies.

[0028]

[Table 1]

Comparative Example 2 A waste paper sheet, an unbleached hardwood sheet and a softwood pulp sheet were cut into the lengths shown in Table 2. In order to prevent the fiber length from becoming too short, the sheet must be
Dispersed in water in twice the amount of water. Six types of samples (1) to (6) were prepared by adding 70 parts by weight of cement and 30 parts by weight of silica stone to the fibers shown in Table 2 by weight. Add hydroxypropyl methylcellulose 90SH-100000 (Shin-Etsu Chemical Co., Ltd.) as coagulant,
Each sample was subjected to sheet molding in the same manner as in Example 1,
Table 2 shows the evaluation results.

Separately, the crude linter fiber was made into sodium xanthate, and the sodium xanthate was spun to produce viscose rayon fiber. To 70 parts by weight of cement and 30 parts by weight of silica stone, the fibers of the parts by weight shown in Table 2 were added to prepare two types of samples (7) to (8). Polyacrylamide coagulant KL-1 as coagulant
1B (manufactured by Hymo Co., Ltd.) was added, and the paper was formed in the same manner as in Example 1. The evaluation results are shown in Table 2.

[0031]

[Table 2]

Example 2 Cellulose was dissolved in N-methylmorpholine-N-oxide (N-methylmorpholine-N-oxide hydrate manufactured by Nippon Emulsifier Co., Ltd.), and the solution was spun by a solvent to give a diameter of 10%.
Cellulose fibers having a size of μm or less were produced. This cellulose fiber was cut into a length of 6 mm, and 70 parts by weight of cement and 30 parts by weight of quartzite were added with the fiber of the weight shown in Table 3 to obtain four types of (1) to (4). Make a sample. These samples were mixed for 500 r using a Henschel mixer.
Mix for 3 minutes at pm. Binders were added in each case based on the parts by weight indicated in Table 3. (1) and (4)
The binder to be added is hydroxypropyl methylcellulose 90SH-100000 (manufactured by Shin-Etsu Chemical Co., Ltd.), (2)
The binder added to (3) is hydroxyethyl methylcellulose SNB-30T (manufactured by Shin-Etsu Chemical Co., Ltd.), and the binder added to (3) is methyl cellulose SM-8000 (manufactured by Shin-Etsu Chemical Co., Ltd.).

Then, the mixture was kneaded with a 10-liter double-arm kneader for 5 minutes and extrusion molding was performed, and the molding state of the molded body was observed. After the molded body was cured at 45 ° C. and 100% humidity for 24 hours, it was further autoclaved at 170 ° C. and 9 kg / cm ² for 8 hours. The mechanical strength, nailing property, and molded state were evaluated, and the results are shown in Table 3. Evaluation of mechanical strength was performed by measuring impact strength, curing time, bending strength, and compression strength.

The impact strength is measured in the same manner as in Example 1.

The curing time is as follows: 30 g of the molded product immediately after being discharged from the extrusion molding machine is rolled, put in a plastic bag, cured in a 45 ° C. constant temperature bath, and then the molded product is obtained by placing 20 kg of stone on the rounded molded product. It is the time when it does not deform.

The flexural strength and compressive strength are measured in the same manner as in Example 1.

Nailability The molded body was cured for 24 hours at 45 ° C. and 100% relative humidity, and then autoclaved for 8 hours at 170 ° C. and 9 kg / cm ² , and a 5 mm-diameter nail was formed on a 6 mm thick molded body. It was evaluated whether the molded body was broken or not broken by punching.

Comparative Example 3 Viscose rayon was mixed with 70 parts by weight of cement and 30 parts of silica stone.
Four types of samples (1) to (4) were prepared by adding fiber parts by weight shown in Table 3 to parts by weight. Hydroxypropyl methylcellulose 90SH as binder
-100000 (manufactured by Shin-Etsu Chemical Co., Ltd.) was added, and extrusion molding and curing of the molded body were performed in the same manner as in Example 2. The mechanical strength and nail punching property were evaluated, and the results are shown in Table 3.

[0039]

[Table 3]

Comparative Example 4 A waste paper sheet, an unbleached hardwood sheet, a softwood pulp sheet, and a linter pulp sheet were cut into the lengths shown in Tables 4 and 5. The sheet is previously dispersed in water in an amount of water 16 times the sheet weight so that the fiber length is not too short. Sixteen types of samples (1) to (16) were prepared by adding 70 parts by weight of cement and 30 parts by weight of silica to the parts by weight shown in Tables 4 and 5.
Hydroxypropyl methylcellulose as binder
Example 2 with the addition of 90SH-100000 (Shin-Etsu Chemical Co., Ltd.)
Extrusion molding and curing of the molded body were performed in the same manner as described above. The mechanical strength and the nail punching property were evaluated, and the results are shown in Tables 4 and 5.

[0041]

[Table 4]

[0042]

[Table 5]

Example 3 50 parts by weight of cement, 50 parts by weight of No. 5 quartzite, Example 1
2 parts by weight of cellulose fiber used in the above and hydroxypropyl methylcellulose (90-SH4000 manufactured by Shin-Etsu Chemical Co., Ltd.)
) 0.5 part by weight was mixed with a Henschel mixer for 3 minutes. Thereafter, 50 parts by weight of water was added to the mixture, and the mixture was kneaded with a mortar mixer to prepare a mortar. Mortar width 4
cm, thickness 2 cm, length 10 cm, and width, thickness 15 mm, length 5 cm in a metal frame, cured for 1 week at 20 ° C. and 100% relative humidity. , And compressive strength were measured in the same manner as in Example 1. The impact strength was 3.5 kg · cm / cm ² , the bending strength was 70 kg / cm ² , and the compressive strength was 150 kg / cm ² , and it could be sufficiently used as a building material.

Comparative Example 5 Mortar was molded, cured and measured in the same manner as in Example 3 except that no fiber was added. The molded body has cracks and the impact strength is 2.1 kg · cm /
With cm ² , the material was more easily broken than in Example 3.

Example 4 The mortar produced in Example 3 was sprayed on a concrete wall with a thickness of 5 mm using a spraying apparatus DM (manufactured by Zenki Kogyo).
The peel strength of the mortar hardened by standing for 4 weeks was measured. Peel strength is the strength at which the mortar peels from the concrete wall. The mortar has a peel strength of 7 kg / cm ² ,
There was no crack and it could be used as a building material.

Comparative Example 6 The mortar of Comparative Example 5 containing no fiber was sprayed on a concrete wall in the same manner as in Example 4. When the surface was observed four weeks later, many cracks were found on the surface. The peel strength was also 4 kg / cm ² , which was lower than that of Example 4.

Example 5 The mortar used in Example 4 was applied to a concrete wall with a plastering iron, applied to a thickness of 5 mm, and cured for 4 weeks. After that, the surface was observed, but there was no crack and the peel strength was 6 kg.
/ Cm ² , which was sufficient for use as a building material.

Comparative Example 7 The mortar of Comparative Example 6 containing no fiber was applied to a concrete wall with a plastering iron in the same manner as in Example 5, and the thickness was 5 mm.
And cured for 4 weeks. After that, when the surface was observed, a crack was generated on the surface, and the peel strength was 2 kg / cm.
^2, which is lower than that of Example 5.

[0049]

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-5-186253 (JP, A) JP-A-6-40755 (JP, A) JP-A-6-163324 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) C04B 16/02 C04B 16/06 D01F 2/00-2/30

Claims (6)

(57) [Claims] 1. A method of preparing a polymer solution by dissolving cellulose in an amine oxide solvent, filtering the polymer solution, and spinning the filtrate in an aqueous solution to contain cellulose fibers as reinforcing fibers. Cement composition. 2. The cement composition according to claim 1, wherein the cellulose fibers have a diameter of 10 μm or less and a fiber length of 3 to 10 mm. 3. The cement composition according to claim 1, wherein the amine oxide solvent is N-methylmorpholine-N-oxide and / or N-ethylmorpholine-N-oxide. 4. A cementitious extrusion molding composition comprising the cellulose fiber as a reinforcing fiber. 5. A cementitious papermaking / molding composition comprising the cellulose fiber as a reinforcing fiber. 6. A composition for cast molding of a cementitious form, comprising the cellulose fiber as a reinforcing fiber.