JPS62182141A - Hydraulic composition - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention provides a hydraulic fiber which is made by blending fibrillated fibers with excellent heat resistance, chemical resistance and mechanical strength and non-fibrillated reinforcing fibers. Regarding the composition.

(Conventional technology) Conventionally, reinforcing materials for hydraulic materials such as cement and gypsum were
Asbestos is widely used.

However, the price of asbestos fluctuates widely,
Not only does the product cost vary depending on the price of asbestos, but it has also become clear that asbestos dust impairs the health of workers.Therefore, there has been a growing demand for fibers that can replace asbestos, and so far glass fibers, Carbon fiber, steel fiber, olefin fiber, “vinylon′”,
Many fibers have been proposed as asbestos substitutes, including acrylic fibers and aramid fibers. Among these fibers, acrylic fibers are attracting attention because of their low price, high strength, and excellent alkali resistance, and are being used in place of asbestos for cement reinforcement, especially in the field of slate.

However, this acrylic fiber has a significantly larger fiber diameter than asbestos, so it cannot effectively capture cement particles during the manufacturing process of slate manufactured by the papermaking method, and it passes through the wire mesh of the circular mesh cylinder. Cement particles end up flowing out into the wastewater. Therefore, the acrylic fiber is not used alone, but is usually used in combination with fibrillar fibers such as waste paper pulp and wood pulp (ff), but when used in combination with these pulps, organic matter in the slate is However, there have been problems in that the flame retardance is decreased due to an increase in the flame retardance, and the dimensional stability of the slate is decreased due to the hygroscopicity of the pulp.

In order to improve the drawbacks of this acrylic llff as an asbestos substitute, for example, Japanese Patent Publication No. 53-46923 discloses that 60 mol% or more of acrylonitrile (hereinafter referred to as AN
It has been proposed that an acrylic fiber made of a copolymer of 40 mol% or less of vinylcarboxylic acid and treated with an alkaline aqueous solution and then beaten has been proposed, but it has a high degree of fibrillation and a low water content. In order to obtain acrylic fibers, it is necessary to mix and spin a large amount of AN-based polymer with a large amount of copolymerized components, which deteriorates chemical resistance such as alkali resistance and heat resistance, and also causes mechanical problems. Because of its reduced strength, it was unsatisfactory as an asbestos substitute for cement reinforcement.

Furthermore, JP-A-56-100163 discloses that a film or tape made of an AN-based polymer having a molar concentration of AN of 33% or more and preferably 93% or less is fibrillated and is used as a reinforcing fiber. A hard material has been proposed, but this acrylic fibrillated fiber has a limited degree of fibrillation and requires the use of waste paper pulp in the slate making process, resulting in unstable dimensional stability of the slate. It was enough. In addition, because of the large amount of copolymerized components, the alkali resistance was poor, the durability of the slate was low, and there were problems in practical performance.

(Problems to be Solved by the Invention) The object of the present invention is to have a high degree of fibrillation, that is, a low water content, and to have chemical resistance such as alkali resistance, heat resistance, and mechanical properties. By blending fibrillated acrylic fibers with excellent strength and non-fibrillated reinforcing fibers into a hydraulic material, a hydraulic composition with excellent paper formability in the manufacturing process of slate etc., especially mechanical strength such as bending strength. An object of the present invention is to provide a hydraulic composition that provides molded products such as slate with excellent strength and high dimensional stability.

(Means for Solving the Problems) As described in the claims, the object of the present invention is to provide a 1-l hydraulic material containing at least 95% acrylonitrile and having an intrinsic viscosity of 2.5 or more, the tensile strength before fibrillation is at least 10 g/d or more, and the P water content is 600 cc or less and 0.1 to 10 mm is blended at 5% or less. This can be achieved by a hydraulic composition.

One of the features of the present invention is that it is made of a fibrillated polymer with a high polymerization degree of A or higher, and by constructing the fiber from such an AN-based polymer, its mechanical strength, especially Tensile strength before fibrillation is 10g
A fibrillated fiber with high strength of /d or more and excellent chemical resistance can be obtained. Another important feature is that the fibrillated acrylic fiber has a P water content of 600 cc or less. This has an excellent effect on the paper-making properties of slate in the paper-making method.

In order to obtain a highly fibrillated fiber with a high tensile strength and a water resistance of 600 CC or less using an AN-based polymer having such a polymer composition and degree of polymerization, the details are described below. It is necessary to employ specific manufacturing means.

That is, first, as a spinning method, a spinning stock solution of an AN-based polymer having the above composition and degree of polymerization is once discharged from a spinneret hole into an inert atmosphere such as air, nitrogen, argon, helium, etc., and this discharged polymer is inactivated. Fiber threads are formed by the so-called dry/wet spinning method, in which the fibers are passed through a microscopic space in the atmosphere and introduced into a coagulant in the spinning dope to coagulate.

In order to make a high-strength fiber from an N-based polymer in which the polymer chains of the polymer are highly oriented in the fiber axis direction and have a tensile strength of 10q/d or more, it cannot be produced by normal wet spinning or dry spinning. , can only be produced by applying the above-mentioned dry/wet spinning.

The obtained fibers have a fiber length of 0.1 to 10
Cut into pieces of mm and punch 1. It is desirable that the fibrillation temperature is m"t, but in this case, the degree of fibrillation of the fibers by beating should be such that the degree of fibrillation of the fibers is 6000C or less, preferably 200C or less.
It is necessary to beat the material to within a range of 5000C. In other words, the requirement of P suiseki 600cc or less is,
When producing slate by the papermaking method, the filtration rate of the cement slurry in the round cylinder is reduced, thereby; the filtration area is increased and more solids are scooped onto the cylinder and discharged from the cylinder. This is extremely important in terms of paperability, such as preventing cement particles from flowing out.

Polymerizable monomers, such as dicarboxylic acids such as acrylic acid, methacrylic acid, and itaconic acid, and their lower alkyl esters, and hydroxyalkyl containing a hydroxyl group of carboxylic acids such as hydroxymethyl acrylate, hydroxyethyl acrylate, and hydroxymethyl methacrylate. There are copolymers with acrylate, acrylamide, methacrylamide, α-chloroacrylonitrile, hydroxyethyl acrylic acid, allylsulfonic acid, methacrylsulfonic acid, etc.

The conditions for dry/wet spinning are as follows: A spinning stock solution having a solution viscosity of 2,000 voids or more, preferably 3,000 to 10,000 voids, and a polymer concentration of 5 to 20% is prepared by dissolving it in an inorganic solvent such as a concentrated aqueous solution of an inorganic salt or nitric acid. The distance between the spinneret surface and the coagulation bath liquid level is set within the range of 1 to 20 mm, preferably 3 to 10 mm, and the spinning dope is formed by the spinneret surface and the coagulation bath liquid surface from the spinneret hole. After discharging it into a microspace, it is introduced into a coagulation bath and coagulated, and then the obtained coagulated fiber thread is washed with water, desolventized, primary stretching, drying/densification, secondary stretching, heat treatment, etc. The fibers are passed through a processing step to form drawn fiber threads.The fiber threads obtained by this dry/wet spinning have extremely excellent drawability.
Preferably, as a secondary stretching method, stretching is carried out by 1.1 times, preferably 1.5 times or more, under dry heat at 150 to 270°C, so that the total effective stretching ratio is at least 10 times, preferably 12 times or more. It is preferred that the fineness is within the range of 0.1 to 10 denier (d), preferably 0.5 to 5 d.

The fibers thus obtained usually have a tensile strength of 10 q/d or more, a tensile modulus of 1800/d or more, and a knot strength of 2.2.
It has mechanical properties of q/d or more, and has an X-ray crystal orientation of 93
% or more.

The obtained fibers have a length of 0.1 to iQr, as described above.
After being cut to T1m, a beating means such as a beater, refiner, Victory mill, Pulvera, Iser, ball mill, PEI mill, jet air flow, etc. is applied to obtain a water degree of 600 CC or less, preferably 200 to 200 CC, as described above.
It is fibrillated to a range of 500 cc.

The amount of this fibrillated acrylic fiber in the hydraulic composition is 0.5 to 10 mm%, preferably 2
The range of 6% to 6% is preferable. If this amount is less than 0.5%, it will not be possible to provide sufficient paper formability to the hydraulic composition, and it will not be possible to provide a sufficient reinforcing effect to the resulting molded product, and if it exceeds 10%. This is not preferable because the dispersibility of the fibrillated fibers in the hydraulic composition deteriorates.

In addition to the above-mentioned fibrillated acrylic fibers, the hydraulic composition of the present invention includes non-fibrillated acrylic fibers.
That is, it is necessary to incorporate non-fibrillated fibers as reinforcing fibers.

Examples of such non-fibrillated fibers include alkali-resistant glass fibers, inorganic fibers such as carbon fibers, "vinylon", high-strength acrylic fibers, and aramid fiber ML known under the trade name "Kebrapa". However, non-fibrillated fibers, which are the raw materials for the fibrillated acrylic fibers, are preferable.
Considering adhesion to hydraulic substances such as cement, alkali resistance, water absorption, and dimensional stability of the product,
The high-strength acrylic fiber, more preferably, has a knot strength of 2.2 q/d or more, an X-ray crystal orientation of 93% or more, and a fineness of 0.1 to 10 denier (d), preferably 0.2 q/d or more.
Those with a fiber length of 5 to 5 d and a fiber length of 0.5 to 15 mm are right-handed.

The blending amount of this reinforced lli navy blue is 5% by weight or less,
Preferably, it is within the range of 0.1 to 3%, and if it is outside this range, the dispersibility in the hydraulic composition will decrease and no reinforcing effect can be expected, so it is not preferable.

Roughly, the fibrillated fibers and non-fibrillated fibers of the present invention may contain surfactants, resin emulsions, and polymers in order to improve the adhesion and dispersibility of the fibrillated fibers and non-fibrillated fibers to hydraulic substances. A flocculant may also be attached.

In particular, the addition of nonionic or cationic polymer flocculants is
For example, it has an excellent effect on improving the formability and bending strength of cement boards and the like.

Further, as the hydraulic substance constituting the hydraulic composition of the present invention, inorganic substances that harden by hydration, such as portland cement, alumina cement, slag cement,
Examples include silica cement, gypsum, and calcium silicate.

In order to give these hydraulic materials a porous structure or a lightweight structure, pearlite, shirasu balloons, glass balloons, etc. can be blended.

Various known methods can be used to produce molded products such as cement boards from the hydraulic composition of the present invention. For example, there are methods such as the Hachinic method, in which a slurry of a hydraulic material is made into a cement board, a method in which a hydraulic composition such as cement is sprayed, and a method in which a hydraulic composition is injected into a mold. Preferably, the Hachinik method is used.

In the hydraulic composition of the present invention, the fibrillated acrylic fibers and reinforcing fibers blended therein have good stability,
The molded products obtained from this hydraulic composition, which are dispersed and blended and exhibit excellent paper formability, are 1q superior to hydraulic compositions containing asbestos in terms of chemical resistance, dimensional stability, and mechanical strength. It has performance that surpasses that of other products. In particular, slate products manufactured using the papermaking method show good papermaking properties even without incorporating natural pulp with high water absorption, and are extremely superior not only in bending strength but also in dimensional stability and impact resistance. It has excellent performance,
This provides a slate product useful in many applications, including building and civil engineering materials.

Hereinafter, the effects of the present invention will be explained in more detail with reference to Examples.

In the present invention, the intrinsic viscosity, water level, cement slurry filtration rate, cement permeability, and properties of the cement board are values measured by the following measuring method.

A dry AN-based polymer with an intrinsic viscosity of near 5 mq was placed in a flask, and DMF2 containing 0.1N sodium diocyanate was added.
Add 5 ml and dissolve completely.

The obtained polymer solution is 2 using Ostwald viscosity h1.
The specific viscosity is measured at 0°C, and the intrinsic viscosity is calculated according to the following formula.

Intrinsic viscosity = Tomizu stone: Canadian standard; Tomizu degree, JIS-P-
The measurement was performed according to the measurement method specified in 8121.

Cement slurry filtration rate and cement permeability: fibrillated acrylic fibers 0.6CI, Ca(O
H) 20.6g, Al1 (SO4) 30°60, Portland cement 28.2CI were added to water 11, stirred and mixed, then 1100pp of anionic polyacrylamide polymer flocculant was added and slowly stirred to form the cement. Got slurry. Next, 50% of the above cement slurry
The cement was passed through a wire mesh having an area of 82 cm2, and the filtration rate (cc/min>) and the percentage of cement passing through the wire mesh (weight %) were measured to determine the transmittance.

Bending strength: A test piece was cut out from a cement board and measured according to the measuring method specified in JIS-6911.

Water absorption rate and water absorption length change rate: A test piece was cut out from a cement board and tested according to JIS-A-541.
The measurement was performed according to the measurement method specified in Section 8.

Specific Gravity: For a test piece cut out from a cement board, bone dry, saturated, and submerged particles were measured, and the specific gravity was calculated based on the following formula.

Specific gravity = Absolute dry weight / (saturated limbs - weight in water) Examples 1 to 4
, Comparative Examples 1 to 3 100% AN was solution polymerized in DMSO to create AN-based polymers having different intrinsic viscosities shown in Table 1. The resulting polymer solution was heated to a viscosity of 3000 poise (45°C).
The polymer concentration was adjusted so that the spinning dope was prepared.

Wet spinning and dry/wet spinning were performed using these spinning stock solutions, respectively. As the coagulation bath, a 20'C155% DMSO aqueous solution was used in all methods. Also,
In the case of dry/wet spinning, the distance between the spinneret and the coagulation bath liquid level was set to 5 mm, and the distance from the coagulation liquid level to the focusing guide was 400 mm.

The obtained undrawn 11m yarn was stretched 5 times in hot water, washed with water, applied with an oil agent, and subjected to secondary stretching at 90% of the maximum stretching ratio in a dry heat tube at 180 to 200°C. , 1st
The acrylic fibrillated fibers shown in the table were obtained.

The acrylic optical fibrillated fibers shown in Table 1 were cut to a fiber length of 5 mm, and the cut fibers 20C1 were approximately 10 cm long.
of water, and then fibrillated through a single disc refiner set at clearance Q, imm.

The fiber lengths of the obtained acrylic fibrillated fibers ranged from about 0.1 to 5 mm, depending on the length of the acrylic fibers before fibrillation. In addition, the results shown in Table 1 were obtained for P-suiseki. Next, the tomizu stone and cement permeability of the cement slurry containing the acrylic fibrillated fibers were measured to evaluate the paper formability of the acrylic fibrillated fibers. Table 1 shows the measurement results of the transit velocity and cement permeability of cement slurry using these acrylic fibrillated fibers.

Next, 10Cl, Ca(
OH) 210g, Al1 (SO4) 310CI in water 1
After adding to 01 and stirring, Portland cement 46
0Cl was added and stirred again. Subsequently, anionic polyacrylamide polymer flocculant 2oopp was added under low speed stirring.
m was added. The obtained cement slurry was transferred into a 20 cm x 25 cm mold lined with a 50 mesh wire mesh, filtered, and then pressed at a pressure of 100 KQ/cm2 for 1 minute to form a cement board with a thickness of about 5 mm. Next, 2
After curing for 1 day at 0°C and 1100% RH, and then for 6 days as shown in Table 1 in water at 20°C, test pieces were cut from the cement board and the bending strength was measured in a wet state. The results are shown in Table 1.

The fibrillated fibers obtained from high-strength acrylic fibers made from the highly polymerized acrylic polymer of the present invention by dry/wet spinning have: small tomizu stones, good fibrillation, and a high filtration rate of cement slurry. It also had low cement permeability and excellent paper formability. Furthermore, the cement board of the present invention had high bending strength and excellent performance.

Example 5 and Comparative Example 4 Obtained in Example 3; acrylic fibrillated fibers of 390 cc of Shito Mizuseki (Example 5), waste paper valve of 350 cc of Shito Mizuseki (Comparative Example 4), and reinforcing fibers of Example 2. A cement slurry was prepared using the acrylic fibrillated fibers in the same manner as in Example 1, its filtration rate and cement permeability were measured, and then a cement board was formed. In addition, the water absorption rate and length change rate after drying the cement board immersed in water at 60'C and 105C in Table 2 were measured.

The results are shown in Table 2.

From Table 2, it can be seen that the cement board using the acrylic fibrillated fibers of the present invention has greater bending strength and superior dimensional stability when wetted compared to the cement board using natural bulbs.

Claims (2)

[Claims] (1) The hydraulic material is made of an acrylonitrile polymer containing at least 95 mol% of acrylonitrile and has an intrinsic viscosity of 2.5 or more, has a tensile strength before fibrillation of 10 g/d or more, and has a capacity of 600 cc or less. A hydraulic composition comprising 0.5 to 10% by weight of fibrillated acrylic fibers having freeness and an average fiber length of 0.1 to 10 mm and 5% by weight or less of non-fibrillated reinforcing fibers. (2) In claim 1, the non-fibrillated reinforcing fibers are made of an acrylonitrile polymer containing at least 95 mol% of acrylonitrile and have an intrinsic viscosity of 2.5 or more, and have a tensile strength of 10 g/d or more. Strength and 1
A hydraulic composition that is an acrylic fiber having a tensile modulus of 80 g/d or more.