JPS5855100B2 - Manufacturing method for glass fiber reinforced cement products - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing glass fiber reinforced cement products having extremely high strength and excellent durability.

Glass fiber is used as FRP (Fiber-Reinforced) because of its excellent tensile strength and high elastic modulus.
It is currently widely used as a reinforcing material suitable for fiber-reinforced composite materials such as plastics.

Particularly in recent years, there has been a strong demand for higher strength cement products, and research on glass fiber reinforced cement has been considered in various fields.
Asbestos, which is a reinforcement material for J-lux, is in a state of depletion, which not only increases the price, but also makes it difficult to obtain, and also causes pollution problems due to a decline in quality, so there is a strong need for asbestos substitutes. It is requested.

Against this background, research has been conducted in various places on alkali-resistant glass fibers that are less likely to be corroded by the alkali components in cement.

For example, British Patent No. 1,290,528 describes that glass fibers with excellent alkali resistance can be produced by using 7 to 11 mol % of ZrO2 as a constituent of the glass.

These fibers are then usually cut to the appropriate length,
It is believed that by using it as a reinforcing material in a cement matrix, thin, high-strength glass fiber-reinforced cement products can be manufactured.

In this way, efforts have been made to improve the durability of glass fibers in cement by imparting alkali resistance to the glass fibers themselves.

Furthermore, attempts have been made to improve the deterioration of glass fibers in cement by attaching additives such as pyrogallol to the fiber surface.

(Japanese Unexamined Patent Publication No. 5C-31191) Furthermore, the durability of glass fibers can be improved by adding and mixing other inorganic compounds (for example, pozzolan such as activated silica, activated alumina, etc.) to the cement matrix to modify the matrix. Attempts have also been made to do so.

However, even with these various improvements, glass fiber reinforced cement products still have many problems in practical use.

For example, the physical properties of glass fiber-reinforced cement products obtained by making full use of these methods, such as strength (flexural strength, impact strength, etc.), are still insufficient for practical use. However, the durability of the obtained cement products is not necessarily satisfactory, and due to the deterioration of the glass fibers after many years of use, the bending strength, impact strength, etc. of the cement products decrease, and they are currently not practical. It is considered difficult.

The present inventors conducted research on these two problems from the viewpoint of modifying the cement matrix and completed the present invention.

An object of the present invention is to provide a glass fiber-reinforced cement product that has excellent bending strength, impact strength, etc., and good durability.

Another object is to provide a method for manufacturing such glass fiber reinforced cement products industrially easily and inexpensively.

That is, the method of the present invention uses Z having an alkali solubility of 4% or less.
When adding rO2-containing alkali-resistant glass fiber to cement to produce glass fiber-reinforced cement products, glass fiber, vinyl polymer, and water are added to 100 parts by weight of cement using the following formulas (1) and (2) at the same time. After mixing in a satisfactory range of composition, 1-
After curing for 100 days and the moisture content of the obtained cured product reaching 15% by weight or less, the cured product was
It is characterized by dry heat treatment at a temperature of C.

1 <, x <30 (1) o, iy≦w+x’ 0.02x2≦37-0.1y (2) (However, X : Vinyl per 100 parts by weight of cement parts by weight of polymer, :Water per 100 parts by weight of cement weight part, : Gala per 100 parts by weight of cement Parts by weight of fibers are shown.

) Since the glass fibers produced by the method of the present invention are used in combination with cement in the form of Mah IJ socks, they must have alkali resistance.

In this sense, ZrO whose alkali solubility is 4% or less
2-containing alkali-resistant glass fiber is a suitable material.

Here, the alkali solubility means that 2 g of glass fiber with a fiber diameter of 13 ± 02 μ is mixed with 100 g of 10% NaOH aqueous solution at 95°C.
The figure shows the degree of weight loss of the glass fibers as a percentage when immersed in the water for 1 hour.

The glass that can be used in the method of the present invention includes at least Zr.
Although it is necessary to contain 5 mol% of O2, the alkali resistance generally shows a tendency to increase with the ZrO2 content, so the glass fiber in the present invention contains ZrO2 of 10 mol% or more, preferably 11 mol% or more, and most preferably 11.
The ground content is 5 mol%.

Examples of glass compositions satisfying the above conditions include SiO2: 50 to 76%, ZrO2: 8 to 16%, and R2 in terms of mol%.
0: l0-25%, l? 0:o~10%, CaF2:0
~2%, B2O3: 0-7%, P2O5: 0-5%, S
nO2: 0-7.5% and other metal oxides: 0-1
A glass fiber consisting of 0%, in the above composition R is Li
, Na or K; R' represents Ca, Mg, Ba, Zn, Mn or pb; other metal oxides include Al2O;
3, Fe2O3, TiO2°CeO2, etc.

Among the above compositions, a more preferable composition is, for example, a composition (mol %) excellent in vitrification and spinning operability:
SiO2: 55-69%, ZrO2: 10-14%, R
20: 12-23%, B2O3: 1-6%, F20. :
A glass fiber with excellent alkali resistance, characterized in that the content of R'0 is 1 to 5% and does not exceed 0.5%, and the content of other metal oxides introduced as impurities does not exceed 1%. be.

In addition, glass compositions (mol%) that are particularly durable in cement include 5in2: 50-69%, ZrO2:
l O-13%, R20: 10-22%, R20: 1-
7%, B2O3: 1-7%, Al2O3: 0-5%, P
2O5: 0 to less than 1%, provided that R20 in the above
represents Na2O, up to 3% of which can be replaced by Li2O, and the total amount of R20 and R20 is 14~
It is 25%.

In addition, the content of R'0 is less than 1% (however, R' represents an alkaline earth metal), and the fluoride is converted to F2.
It is an alkali-resistant glass fiber characterized by having a content of 1% or less.

In addition, although it has a slight disadvantage of high spinning temperature in spinning operation, it is advantageous in terms of alkali resistance and cost of glass forming raw materials as a glass composition (mol%) of 5102.
:50-69%, ZrO2:1O13.5%, R20:
1-7%, R, 0: 10-25%, R'O: 1-10
%, B2031-7%, P2O5:O to less than 1%, A
l2O3: 0-2%, CaF2: 0-2%, however, in the above R20 is Na2O or/and L l20
The total amount of R20 and 20 is 14 to 26%, R' represents an alkaline earth metal, Zn, Mn, and the content of F2 is 2.5% when fluoride is converted to F2. It is an alkali-resistant glass fiber that is underground.

These glass fibers are produced by placing glass raw materials in a crucible made of mullite, for example, and heating them at 1,300 to 15
It can be produced by heating at a melting temperature of 00° C. for 3 to 60 hours to form a homogeneous glass into a rond or marble shape, and then subjecting it to a melt-spinning process.

In the melt spinning process, 200 to 2000 holes (
The glass is made into fibers by drawing out the molten glass from the glass chip and winding it up at a spinning speed of 1,000 to 4,000 m/min while applying a sizing agent.

The sizing agent used when winding the melt-spun glass fibers is added to improve operability during winding the glass fibers and in subsequent processing steps, but the sizing agent used in the method of the present invention Generally, the main ingredients are a sizing agent and a smoothing/softening agent.

In some cases, additives that are thought to slightly modify the alkaline atmosphere around the glass fibers when the glass fibers are mixed into the cement may be mixed.

Furthermore, an aminosilane coupling agent can also be used for the purpose of further improving the cohesiveness of the glass fibers.

As the sizing agent, commonly used sizing agents for glass fibers can be used, such as vinyl acetate polymers, copolymers of ethylene and vinyl acetate, and copolymers of vinyl acetate and acrylic acid and their esters. Polymers such as acrylic acid polymers, acrylic ester polymers, epoxy resins, phenolic resins, various starches, polyvinyl alcohol, etc. are suitable.

In addition, various nonionic or cationic activators such as polyethylene glycol are suitable as smoothing and softening agents.

As additives, cement hardening retarders such as gluconic acid and lignin sulfonate, or aromatic compounds having multiple hydroxyl groups such as pyrocatechin, resorcinol, and pyrogallol can be used, but in particular, glucose or sucrose may be used. is preferred.

The amount of the sizing agent obtained here attached to the glass fiber is 0.3 to 5% by weight, preferably 0.8 to 3% by weight.

High-strength, high-impact cement products can be created by incorporating the obtained glass fibers into a cement matrix, but the method of the present invention improves the properties of cement products by simultaneously using a vinyl polymer. The purpose is to further improve the durability of the cement product over many years.

The amount of alkali-resistant glass fiber to be mixed is within a range that satisfies equation (2), but it is usually 1 part by weight of cement loO.
~20 parts by weight, preferably 3 to 16 parts by weight.

Vinyl polymers that can be applied to the method of the present invention include homopolymers such as vinyl acetate polymer, polyethylene, polypropylene, polystyrene, polybutadiene, polyacrylic acid, polymethacrylic acid, and polyacrylic ester;
Ethylene-vinyl acetate copolymer, vinyl acetate-acrylic acid copolymer,
These include bee-acetate acrylic ester copolymer, styrene-acrylic acid copolymer, styrene-acrylic ester copolymer, and styrene-bucdiene copolymer, among which acrylic Acid ester containing polymers are preferred.

These polymers may be used alone or in combination.

The amount of the vinyl polymer added to cement is 1 to 30 parts by weight, preferably 3 to 25 parts by weight, particularly 7 to 22 parts by weight, based on 100 parts by weight of cement.

If the amount added is less than 1 part by weight, it is not preferable because the properties such as strength and impact of the final product cannot be greatly improved, nor can the durability be greatly improved.

If the amount added exceeds 30 parts by weight, the physical properties of the final product can be significantly improved, but the resin and cement matrix will phase separate during manufacturing, making it impossible to obtain a homogeneous product and reducing the nonflammability of the product. This is not desirable as it significantly worsens the condition.

In the method of the present invention, the vinyl polymer can generally be added to the cement mortar in the form of an aqueous emulsion, but what is important here is the pH of the emulsion at the time of addition.

The pH must be between 3 and 8, preferably between 4 and 7.

When the pH is less than 3, it has an adverse effect on cement mortar I-IJ lux hardening, and when the pH exceeds 8, deterioration of glass fibers is promoted in the early stage of cement hardening, which is undesirable. The most important issue when mixing and molding glass fibers is the amount of water.

Generally, when preparing a cement slurry, it is known that a water:cemen ratio of 35:100 parts by weight is optimal in terms of fluidity, and that this provides the best physical properties after hardening.

Furthermore, it is generally known that when mixing glass fiber to produce a composite material, it is necessary to slightly increase the water ratio.

In the system using the cement mortar mixed with the vinyl polymer in the present invention, the mixing composition of cement, water, the vinyl polymer, and glass fiber is determined by the following formula, judging from the fluidity and physical properties of the final product after hardening. I learned that I needed to satisfy myself.

That is, o, ty≦w+x 0.02 x 2≦37−o, iy (2) (where X
: Part by weight of vinyl polymer per 100 parts by weight of cement W: Part by weight of water per 100 parts by weight of cement y: Part by weight of glass fiber per 100 parts by weight of cement.

) and particularly preferably 31-o, ty≦w+x-0,02x2≦35-o, t
y (a range that satisfies 2r).

Commonly used antifoaming agents such as sand, water reducing agents, and polyorganosiloxanes can also be used in combination with the mixed composition system.

When using Tazo sand, it is necessary to slightly increase the amount of water within the range of formula (2).

Also, when using a water reducing agent, it is necessary to adjust the amount of water within the range of formula (2), and in the method of the present invention, the water reducing agent is effective in adjusting the fluidity of the slurry during molding. Can be used.

The vinyl polymer used in the method of the present invention is generally mixed into cement mortar in the form of an aqueous emulsion, but it may also be in the form of an aqueous solution.

Further, the time of mixing may be before, at the same time, or after the glass fiber is mixed into the cement mortar.

Cement in which the vinyl polymer is mixed in advance can be used in a spray method or a premix method.

Particularly in the case of the spray method, by spraying glass fibers onto cement mortar and adding the vinyl polymer at the same time, it is possible to modify the cement matrix, especially in the vicinity of the fibers.

This method is particularly preferred when the maximum glass fiber protection effect is expected with a small amount of vinyl polymer.

In addition, when applying the method of the present invention to a papermaking method, cement, glass fiber, and the vinyl polymer are mixed in a large amount of water,
By papermaking, it is possible to create cement products made of cement, vinyl polymer, and glass fiber.

In this case, by means such as pressing after papermaking (2)
It is necessary to satisfy the formula.

The composite thus obtained can be converted into a cement product having excellent physical properties only after undergoing appropriate curing conditions as described below.

Curing in the method of the present invention is divided into two stages.

That is, in the first stage, it is important to gradually advance the water utilization reaction of the cement, reduce the moisture contained in the vinyl polymer appropriately, and slowly form a film.

In this sense, it is necessary to cure the cement in a humid environment for 1 to 100 days at a low temperature, that is, 1 to 50°C.

Here time is correlated with temperature, usually 0-1
15-100 days at 0℃, 3-70 days at 10-20℃
2 to 50 days at 20 to 30°C, 1.5 to 40 days at 30 to 40°C, and 1 to 30 days at 40 to 50°C.

If the curing temperature is less than 0°C, water will coagulate, which is undesirable, and if it exceeds 50°C, defects will occur during film formation of the vinyl polymer, resulting in poor properties of the final product.

Furthermore, the term "wet state" as used herein means that the humidity is 80% RH or more, preferably 90% RH or more, and curing in water is also possible.

If the cement is cured in an atmosphere with a humidity of less than 80%, the final product will not have sufficient strength because the curing speed of the cement will be delayed compared to the film formation of the vinyl polymer.

In addition, when considering the formation of a vinyl polymer film, underwater curing may not be preferable, so the optimum membrane treatment is particularly performed at a humidity of 90-100% RH.

By subjecting the composite obtained by the one-stage treatment to the two-stage dry heat treatment according to the present invention to integrate the cement matrix, the vinyl polymer film, and the glass fiber, various advantages can be achieved. What is important here is that the moisture content of the hardened product before the second stage treatment is 15% by weight or less, preferably 13% by weight or less.
．． The dry heat treatment must be performed after reducing the U content to 5% by weight or less, most preferably 12% by weight or less.

Dry heat treatment is carried out at a temperature of 60 to 150°C, usually at a temperature of 2.
Achieved by performing ~200 hours.

If the dry heat treatment is performed with the moisture content exceeding 15% by weight, the vinyl polymer of the present invention, the cement matrix, and the glass fibers cannot be integrated, and as a result, a cement product with excellent properties cannot be created. do not have.

Further, the term "dry heat treatment" as used herein means heat treatment in air or under an inert gas, and treatment under a N stream is particularly preferred.

The relationship between treatment time and temperature is generally 20 to 200 hours at 60 to 80°C, and 15 to 10 hours at 80 to 100°C.
0 hours, 100-130℃ l0-70 hours, 130
At -150°C, the time is 2 to 50 hours.

If the heat treatment temperature is less than 60℃, it may be because the film formation of the vinyl polymer is weak, or the integration of the vinyl polymer cement and glass fiber is insufficient, and if the heat treatment temperature exceeds 150℃, the heat treatment of the vinyl polymer This is not desirable because it causes decomposition.

Of course, if the temperature is too high, the glass fibers will be degraded by the cement mortar in the early stages of heat treatment, which is not preferable.

Thus, by applying the appropriate two-stage treatment according to the present invention, the deterioration of the glass fibers is minimized and a tough film of the vinyl polymer is formed, so that the cement mortar, the vinyl polymer and the glass fibers are It can be said that by integrating them, it becomes possible to create cement products with extremely excellent physical properties (high bending strength, high impact strength, excellent wear resistance, etc.).

Furthermore, it can be said that it is a safe material with almost no deterioration in physical properties in terms of durability over many years.

The resulting reinforced cement product is a particularly effective material not only as a replacement for conventional cement products but also for FRP.

This will be explained in detail in Examples below.

Example 1 A glass having the following composition 1O2 Z r 02 a20 to 20 203 1203 64.7 mol% 2 8 ■ 0.3 was heated in a crucible with mullite content 2001 at a temperature of 1380°C for 48 hours. It was made by melting it uniformly.

Next, it was molded into a rod shape with a diameter of 0.8 mm and a length of 25 mm.

Next, the content is approximately 1100, which has 204 chips with a diameter of 2 mmφ.
Melt-extruded into a fiber shape at 1300℃ using a platinum-rhodium (80/20%) alloy bushing, 1500m
The sample was wound onto a bobbin at a winding speed of /min.

(Fiber diameter 13.5μ, alkali solubility 1.2%) Here, as a sizing agent, vinyl acetate polymer (by weight%)
VQ-553: Kanebo-NC Co., Ltd.) 14%, dimethyl terephthalate 0.7%, polyethylene glycol (molecular weight 2,000) 1.0%, coupling agent (
An aqueous emulsion solution containing 0.3% (gamma-aminopropyltriethoxysilane) and 0.7% glucose was applied to the fiber bundle using an apron type oiling device.

The obtained bobbin was dried at 125° C. for 8 hours in a hot air circulation dryer.

Further, the sample of the fiber bundle was fired at 700° C. for 3 hours to burn off the organic matter, and the amount of sizing agent adhered was determined from the amount of remaining glass, and it was found to be 1.7%.

Next, Portland cement (manufactured by Onoda Cement ■) 10
An aqueous emulsion consisting of a copolymer of methacrylic acid methyl ester and styrene (l:1 molar ratio) as a vinyl polymer was prepared and mixed in various weight ratios.

Here, the amount of water was adjusted appropriately as shown in Table 1.

The obtained resin-containing mortar and the glass fibers (cut length 25 m0) were molded into a plate shape with a thickness of 10 mm by a conventional spray method.

However, the amount of fiber mixed in is 5.5 parts per 100 parts by weight of cement.
Parts by weight.

After leaving it at room temperature for 1 day, it was demolded and molded at 40℃ and 100% RH.
It was cured for 4 days.

After curing, the moisture content of the hard bodies was measured.

Here, the moisture content was determined by drying under vacuum in a vacuum dryer adjusted to 80'C.

Next, the cured product that had undergone the first stage treatment was placed in a hot air circulation type dryer whose temperature was controlled at 80° C., and heat treated for 48 hours to produce a cement product.

Obtained product sample (thickness: 10 mounds, size: 40 cm x 100 cm)
mm) bending strength (using Instron kg/ff1) and impact strength (using Charpy impact tester: kg/crr)
L/crit) was measured.

In addition, in order to evaluate the durability of the cement product, 60℃×1O
Various resin-containing cement products were left under conditions of 0% RH for 14 days and their bending and impact strengths were measured.

The results are shown in Table 1. It can be seen from Table 1 that the bending strength and impact strength of cement products increase significantly in proportion to the resin content (x).

It is also clear that the durability is significantly improved.

On the contrary, a decrease in performance was observed when the amount exceeded 30% of the 25%.

If the amount is too large, the moldability is generally poor and the final product becomes flammable, which impairs the non-combustibility properties of the cement product, which is undesirable.

That is, the remaining amount of resin is 1 to 30 parts for 1100 parts of Sepha,
Preferably it is 7 to 22 parts out of 3 to 25 parts.

Example 2 A mixture of Portland cement and river sand with a particle size of 1 mm or less in a volume ratio of 1:1 was mixed with 1,100 parts of Sepha (hereinafter referred to as 1100 parts of Sepha) and a vinyl resin obtained by emulsion polymerization of methyl methacrylate and butyl methacrylate in a 7:3 molar ratio. (all parts by weight), mix 20 parts of cement, and add water to 100 parts of cement.
23.5 parts were added and mixed uniformly to prepare a mortar paste.

Next, the glass fibers used in Example 1 were cut into 25 lengths and uniformly mixed into the mortar.

Next, it was molded into a 6-inch thick flat plate, cured for one day at room temperature, and then removed from the mold.

The product was cured at various temperatures for a predetermined period of time, and after measuring the moisture content, it was heat-treated at 85° C. for 50 hours in a hot air circulation dryer to produce a glass fiber reinforced cement product.

After the characteristic evaluation, it was treated in hot water at 80° C. for 7 days, and the durability was also evaluated.

The results are shown in Table 2. It can be seen from Table 2 that the performance and durability of the final product vary greatly depending on the primary curing conditions.

First, when the temperature is low, it is necessary to make the curing time extremely long, and the water content is generally high, which is very disadvantageous in practice.

In particular, when the temperature was -5°C, an excellent product could not be obtained even if curing was continued for 100 days.

In addition, as the curing temperature increases, the moisture content decreases and the bending strength and impact strength of the product increase, which is preferable.
On the other hand, if it exceeds this value, the performance deteriorates, which is undesirable.

Further, from Table 2, it is clear that there is a correlation between water content and bending impact strength, and it is also clear that it is particularly necessary that the water content does not exceed 15% by weight.

A glass fiber having the following composition was prepared according to Example 1.

Next, it was cut into a length of 13 mm. ** On the other hand, perlite (specific gravity 0.3
), and after homogeneous mixing, 15 parts of a copolymer obtained by emulsion polymerization of methyl acrylate, butyl acrylate, and styrene in a 1:1:1 molar ratio were added, and then some water was added. to prepare a homogeneous cement mortar slurry.

Here, the amount of water was 24 parts per 100 parts of cement.

Next, 7.5 parts of the glass fibers were added to 100 parts of cement to form a uniform slurry, and a flat plate with a thickness of 8 mm was prepared.

After curing at room temperature for 2 days, remove the mold and store at 40℃ and 100%RH for 7 days.
I cured it for a day.

The moisture content after curing was 13.9%.

Next, dry heat treatment was performed at a predetermined temperature for a predetermined time to create a cement product.

After performance evaluation, it was treated in hot water at 60'C for 2 weeks to evaluate durability.

The results are shown in Table 3. From Table 3, it can be seen that the properties of cement products change drastically depending on the dry heat temperature.

Low temperatures are generally unfavorable because the bending strength is low.

Furthermore, when the temperature increases, the impact value generally decreases and the bending strength also tends to decrease.

The temperature is 60-150℃, It can be said that it is preferable.

Therefore, the dry heat treatment according to the present invention Especially the temperature of 8O-1200C

Claims (1)

[Claims] 1 Alkali solubility (2 g of glass fibers with a fiber diameter of 13 ± 0.2 μm are dissolved in 100 g of a 10% by weight NaOH aqueous solution at 95°C)
Percentage loss in weight of glass fibers when immersed in water for 1 hour)
When manufacturing glass fiber reinforced cement products by adding ZrO2-containing alkali-resistant glass fibers with a ZrO2 content of 4% or less to cement, glass fibers, vinyl polymers, and water are added to 100 parts by weight of cement using the following formula (1) and ( After mixing with a composition within a range that satisfies 2) at the same time, under moist conditions,
After curing and curing for t-10 days at 0 to 50°C, and after the moisture content of the obtained cured product reaches 15% by weight or less, the cured product is subjected to dry heat treatment at a temperature of 60 to 150°C. Manufacturing method for glass fiber reinforced cement products. 2. The manufacturing method according to claim 1, wherein the alkali-resistant glass fiber containing at least 5 mol% of ZrO2 is used. 3. The manufacturing method according to claim 1, wherein the alkali-resistant glass fiber containing at least 11.5 mol % of ZrO2 is used. 4. The manufacturing method according to claim 1, wherein the vinyl polymer is an acrylic acid ester-containing vinyl polymer. 5. The manufacturing method according to claims 1 to 4, wherein 1 to 20 parts by weight of alkali-resistant glass fiber is mixed with 100 parts by weight of cement. 6 Add 3 to 2 parts of vinyl polymer to 100 parts by weight of cement.
The manufacturing method according to claims 1 to 5, wherein 5 parts by weight are mixed. 7. The manufacturing method according to claim 1, wherein curing is carried out at a temperature of 20 to 40°C. 8. The manufacturing method according to claim 1, wherein the dry heat treatment is performed at a temperature of 80 to 120°C.