Sizing agent for glass fiber, glass strand, and cement composite material

Abstract

To provide a sizing agent for a glass fiber which can improve binding property of a glass strand used in a cement composite material when being mixed with mortar, and can reduce bulkiness, a glass strand using the same, and a cement composite material using the glass strand.SOLUTION: A sizing agent for a glass fiber is a sizing agent for surface film formation of a glass fiber for a cement composite material, contains a solvent containing water, and a solid component as the film, and contains, based on 100 mass% of the solid component, 93 mass% or less of an epoxy resin, and 0.5 mass% or more and 14 mas% or less of an olefin resin.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a sizing agent for glass fibers applied to the surface of glass fibers, a glass strand having a film formed by applying the sizing agent for glass fibers, and a cement composite material using the glass strand.

Background Art

[0002] Glass fiber reinforced concrete (GRC) obtained by mixing glass fibers into mortar is known as a building material that improves the seismic resistance and durability of buildings. As a manufacturing method of GRC, for example, there is known a method (direct method) of spraying glass strands (chopped strands) cut to a predetermined length onto mortar composed of pre-mixed cement, aggregates, water, admixtures, etc. Glass strands are produced by applying a sizing agent for glass fibers to glass fibers (monofilaments) obtained by drawing molten glass from a bushing having a plurality of nozzles and then bundling them.

[0003] There are a direct method and an indirect method for cutting glass strands to obtain chopped strands. The direct method is a method of directly cutting a glass strand in which a plurality of glass fibers are bundled using a sizing agent for glass fibers and drying it to obtain chopped strands. On the other hand, the indirect method is a method of winding a glass strand in which a plurality of glass fibers coated with a sizing agent for glass fibers are bundled and aligned around a collet to form a glass fiber cake as a wound body, drying the glass fiber cake, and then cutting it while unwinding the glass strand from the wound body to obtain chopped strands.

[0004] The film formed on the surface of the glass fiber by applying the sizing agent for glass fibers has functions of preventing the glass fiber from being damaged, preventing the generation of fluff and yarn breakage of the glass fiber, and imparting bundling properties to the glass fiber to improve the workability and strength characteristics during the molding of GRC.

[0005] As a sizing agent for forming a film on the surface of such glass fibers, for example, a sizing agent for glass fibers containing a polyurethane resin having a blocked isocyanate as a raw material component as a solid component has been disclosed (see, for example, Patent Document 1). According to Patent Document 1, since glass fibers exhibit good bundling properties by containing a polyurethane resin having a blocked isocyanate as a raw material component as a solid component, in the mixing step of glass fibers and mortar, it is difficult for the glass strands to be defibrated or cracked. As a result, a decrease in the fluidity of the mortar can be suppressed, and good workability can be obtained.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] However, in the sizing agent for glass fibers described in Patent Document 1, the bundling property of the chopped strands during the mixing of glass fibers and mortar was not yet sufficient. In addition, there were problems such that the obtained chopped strands tended to be bulky and the transportation efficiency decreased.

[0008] In addition, particularly when producing chopped strands by the direct method, the glass fibers tend to be bulkier than in the case of the indirect method. More specifically, in the direct method, the glass strands are cut before a film is formed on the surface of the glass fibers. Therefore, unlike the indirect method, the film is less likely to be damaged by cutting or the like, and the film tends to be rigid. As a result, the obtained glass strands also tend to be rigid and bulky.

[0009] In view of the above, an object of the present invention is to provide a sizing agent for glass fibers that can improve the bundling property of glass strands (chopped strands) used in cement composites when mixed with mortar and reduce the bulkiness, and a glass strand using the same, and a cement composite using the glass strand.

Means for Solving the Problems

[0010] The inventor has found that by adjusting the solid content in the sizing agent for glass fibers so that the content of the epoxy resin is 93% by mass or less and the content of the olefin resin is 0.5% by mass or more and 14% by mass or less per 100% by mass of the solid content, the bundling property of the glass strand when mixed with mortar can be improved and the bulkiness can also be reduced.

[0011] The sizing agent for glass fibers according to Aspect 1 of the present invention is a sizing agent for forming a surface coating of glass fibers for cement composites, and includes a solvent containing water and a solid content that forms the coating. Per 100% by mass of the solid content, it is characterized by containing 93% by mass or less of an epoxy resin and 0.5% by mass or more and 14% by mass or less of an olefin resin.

[0012] In the sizing agent for glass fibers according to Aspect 2 of the present invention, in Aspect 1, it is preferable that the weight average molecular weight of the epoxy resin is 350 or more and 6000 or less.

[0013] In the sizing agent for glass fibers according to Aspect 3 of the present invention, in Aspect 1 or 2, it is preferable that the weight average molecular weight of the olefin resin is 500 or more and 5000 or less.

[0014] In the sizing agent for glass fibers according to Aspect 4 of the present invention, in any one of Aspects 1 to 3, the solid content contains an isocyanate compound, and per 100% by mass of the solid content, it is preferable to contain 5% by mass or more and 50% by mass or less of the isocyanate compound.

[0015] In the sizing agent for glass fibers according to Embodiment 5 of the present invention, in any one of Embodiments 1 to 4, it is preferable that the isocyanate compound is a blocked isocyanate.

[0016] The glass strand according to Embodiment 6 of the present invention is characterized in that it is an aggregate of glass fibers on the surface of which a film composed of the solid component in any one of the sizing agents for glass fibers of Embodiments 1 to 5 is formed.

[0017] In the glass strand according to Embodiment 7 of the present invention, in Embodiment 6, it is preferable that the glass fiber contains 12% by mass or more of ZrO2.

[0018] The cement composite material according to Embodiment 8 of the present invention is characterized by including the glass strand of Embodiment 6 or 7.

Advantages of the Invention

[0019] According to the present invention, it is possible to provide a sizing agent for glass fibers that improves the bundling property of glass strands during mixing with mortar and reduces the bulkiness of glass fibers, a glass strand using the same, and a cement composite material using the glass strand.

Brief Description of the Drawings

[0020]

Figure 1

Embodiments for Carrying Out the Invention

[0021] Hereinafter, embodiments of the sizing agent for glass fibers, glass strand, and cement composite material of the present invention will be described. However, the following embodiments are merely examples, and the present invention is not limited to the following embodiments. Also, in each drawing, members having substantially the same function may be referred to by the same reference numerals.

[0022] <Sizing Agent for Glass Fibers> The sizing agent for glass fibers of the present invention is applied to glass fibers, and in particular, it is used by coating the surface of glass fibers for cement composite materials.

[0023] The sizing agent for glass fibers of the present invention is a sizing agent for forming a surface film of glass fibers for cement composite materials, and includes a solvent containing water and a solid component that forms the film. Per 100% by mass of the solid component, the content of the epoxy resin is 93% by mass or less, and the content of the olefin resin is 0.5% by mass or more and 14% by mass or less.

[0024] Since the sizing agent for glass fibers of the present invention contains 94% by mass or less of an epoxy resin and 0.5% by mass or more and 14% by mass or less of an olefin resin per 100% by mass of the solid component, it is possible to reduce the bulkiness of chopped strands obtained by cutting and packing glass strands. As a result, the transport efficiency and the like can be improved. In addition, since the bundling property of the chopped strands can be improved, when mixed with mortar, the chopped strands are less likely to fibrillate or crack. As a result, even when the chopped strands are mixed with mortar, it is difficult to reduce the fluidity of the mortar, and good workability can be obtained.

[0025] Hereinafter, each component of the sizing agent for glass fibers will be described in detail.

[0026] The olefin resin is a component that can enhance the flexibility and slidability of the coating on the glass fiber surface. Therefore, it is possible to reduce the bulkiness of the chopped strands obtained by cutting and packing the glass strands, thereby improving the transportation efficiency and the like. In particular, as described above, when obtaining chopped strands by the direct method, the coating tends to become rigid and bulky, but by containing the olefin resin, the bulkiness can be reduced. On the other hand, if the content of the olefin resin in the coating on the glass fiber surface is too high, the strength of the coating on the glass fiber surface tends to decrease, and the bundling property tends to decrease. Also, if the content of the olefin resin is too low, it is difficult to obtain the effect of softening the rigidity of the coating, and it becomes difficult to reduce the bulkiness. Therefore, the content of the olefin resin in 100% by mass of the solid component of the glass fiber sizing agent is 0.5% by mass or more and 14% by mass or less. In particular, 1% by mass or more, 2% by mass or more, 2.5% by mass or more are preferable, and 12% by mass or less, 11% by mass or less, 10% by mass or less, 9.5% by mass or less are preferable.

[0027] The weight average molecular weight of the olefin resin is preferably 500 or more and 5000 or less, more preferably 1000 or more, and more preferably 4000 or less. If the weight average molecular weight of the olefin resin is less than the above lower limit, it becomes difficult to improve the flexibility and slidability of the glass fiber surface, and it becomes difficult to reduce the bulkiness of the glass fiber. On the other hand, if it exceeds the above upper limit, when mixing the raw materials during the production of the sizing agent for glass fibers, the raw materials are likely to separate and the workability tends to decrease.

[0028] Examples of the olefin resin include polyethylene resin, polypropylene resin, polyethylene copolymer, etc. Among them, from the viewpoint of enjoying the effects of the present invention at low cost, it is preferable to contain polypropylene resin. These may be used alone or in combination of two or more.

[0029] Epoxy resin is a component that imparts rigidity to the coating on the glass fiber surface and enhances the mechanical strength of the resulting cement composite. On the other hand, if the content of epoxy resin in the coating on the glass fiber surface is too high, the rigidity of the resulting glass strand becomes too high. Therefore, when processing into chopped strands and packing, the gap between each strand becomes large, and it tends to be bulky. As a result, it is likely to cause a decrease in transportation efficiency and the like. In addition, since the coating on the glass fiber surface tends to become hard and brittle, the bundling property is likely to decrease, and the fluidity of the mortar is likely to decrease when mixing with the mortar. Therefore, the content of epoxy resin in 100% by mass of the solid component of the glass fiber sizing agent is 94% by mass or less. In particular, 90% by mass or less, 85% by mass or less, and 80% by mass or less are preferable, and 5% by mass or more, 10% by mass or more, and 20% by mass or more are preferable.

[0030] The weight average molecular weight of the epoxy resin is preferably 350 or more and 6000 or less. In particular, 500 or more is more preferable, and 4000 or less is more preferable. If the weight average molecular weight of the epoxy resin exceeds the above upper limit, aggregates and the like are likely to occur in the sizing agent for glass fibers, and the productivity is likely to decrease. On the other hand, if it is less than the above lower limit, it becomes difficult to improve the bundling property, and the fluidity of the mortar is likely to decrease when mixing with the mortar.

[0031] Examples of the epoxy resin include bisphenol A novolak type epoxy resin, bisphenol F novolak type epoxy resin, biphenyl type difunctional epoxy resin, biphenyl-modified novolak type epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, naphthol-cresol co-condensed novolak type epoxy resin, naphthol-phenol co-condensed novolak type epoxy resin, dicyclopentadiene-phenol addition reaction type epoxy resin, triphenylmethane type epoxy resin, phenol novolak type epoxy resin, cresol novolak type epoxy resin, tetraphenylethane type epoxy resin, naphthol novolak type epoxy resin, and the like. Among them, it is preferable to use bisphenol A novolak type epoxy resin. By doing so, the binding property during mixing with mortar can be improved. These may be used alone or in combination of two or more kinds.

[0032] In addition to the olefin resin and the epoxy resin, the sizing agent for glass fibers of the present invention preferably contains an isocyanate compound and a silane coupling agent as main components.

[0033] The isocyanate compound is a component that can improve the binding property of glass strands. In terms of 100 mass of the solid content of the sizing agent for glass fibers, the content of the isocyanate compound is preferably 1 mass% or more and 60 mass% or less, more preferably 50 mass% or less, 40 mass% or less, and more preferably 5 mass% or more, 10 mass% or more. If it exceeds the above upper limit, the mechanical strength of the cement composite material tends to decrease. On the other hand, if it is less than the above lower limit, it becomes difficult to improve the binding property, and the fluidity of the mortar tends to decrease during mixing with the mortar.

[0034] Examples of the isocyanate compound include diphenylmethane diisocyanate (MDI), dicyclohexane diisocyanate (HMDI), hexamethylene diisocyanate (HDI), tolylene diisocyanate (TDI), isophorone diisocyanate (IPDI), or a polyurethane resin obtained by reacting an isocyanate compound with a compound having a hydroxyl group. From the viewpoint of improving the mechanical strength of the cement composite material, it is preferable that all or part of the isocyanate groups of the isocyanate compound are blocked isocyanates blocked by a blocking agent. When the isocyanate compound contains a polyurethane resin, it is preferably a polyurethane resin obtained by reacting a blocked isocyanate. The blocking agent is not particularly limited, but alcohols, phenols, active methylene, oximes, lactams, amines, and mixtures containing two or more of these components can be used. Examples of the compound having a hydroxyl group used as a raw material for the polyurethane resin include polyether polyol, polyester polyol, and polymer polyol.

[0035] Examples of the silane coupling agent include aminosilane, epoxysilane, vinylsilane, acrylsilane, chlorosilane, mercaptosilane, ureidosilane, and the like. By adding a silane coupling agent, the reactivity between the glass strand and the sizing agent can be improved, and the mechanical strength such as tensile strength can be further improved. In addition to the above silane coupling agent, the sizing agent for glass fiber may contain components such as a lubricant, a nonionic surfactant, and an antistatic agent, and the blending ratio of each component may be determined as needed.

[0036] The sizing agent for glass fiber of the present invention is adjusted as an aqueous solution or an aqueous dispersion having a solid content concentration of 2 to 50% by mass and is applied to the glass fiber. If the solid content concentration is less than 2% by mass, the bundling property of the glass strand may be insufficient. On the other hand, if the solid content concentration exceeds 50% by mass, the components of the sizing agent may not adhere uniformly to the surface of the glass fiber.

[0037] <Glass strand> The glass strand of the present invention is an aggregate of a plurality of glass filaments. The number of glass filaments constituting the glass strand is not particularly limited, but can be, for example, about several tens to several hundreds. The glass filaments are aggregated by applying a sizing agent for glass fibers to the surface.

[0038] The specific composition of the glass filaments is, for example, in mass%, SiO2 54 to 65%, ZrO2 12 to 25%, Li2O 0 to 5%, Na2O 10 to 17%, K2O 0 to 8%, R’O (where R’ represents Mg, Ca, Sr, Ba, Zn) 0 to 10%, TiO2 0 to 10%, Al2O3 0 to 3%, and preferably, in mass%, SiO2 57 to 63%, ZrO2 14 to 21%, Li2O 0 to 3%, Na2O 11 to 16%, K2O 1 to 5%, R’O (where R’ represents Mg, Ca, Sr, Ba, Zn) 0.2 to 8%, TiO2 0.5 to 8%, Al2O3 0 to 1%. When the glass composition is within the above range, glass filaments excellent in alkali resistance can be realized, and it becomes easier to further enhance the mechanical strength of the obtained cement composite material.

[0039] The count of the glass strand is not particularly limited, but is preferably 20 tex or more and 200 tex or less. When the count of the glass strand is within the above range, the fluidity of the mortar and the mechanical strength of the cement composite material can be further enhanced.

[0040] In addition, when the count of the glass strand is less than 20 tex, the surface area of the glass strand becomes large, and the fluidity of the mortar may decrease due to the friction with the mortar.

[0041] On the other hand, when the count of the glass strand is greater than 200 tex, the surface area of the glass strand becomes small, the adhesion area with the mortar decreases, and the mechanical strength of the obtained cement composite material may decrease.

[0042] The glass strands of the present invention are preferably used as chopped strands by being cut. The cut length of the glass strands is not particularly limited, but is preferably 3 mm or more and 40 mm or less. When the cut length is less than 3 mm, while the fluidity of the mortar is improved, the mechanical strength of the cement composite material may not be exhibited. On the other hand, when the cut length is greater than 40 mm, it may become bulky, and thus the fluidity of the mortar may decrease.

[0043] As described above, the surface of the glass filaments of the present invention is covered with a coating. The above coating is formed by applying a sizing agent to the surface of the glass filaments and drying.

[0044] The glass strands of the present invention preferably have a loss on ignition of 0.5 to 2.0% by mass. When the loss on ignition is less than 0.5% by mass, the glass strands may become monofilamented due to physical friction during kneading with the mortar. Therefore, the fluidity of the mortar may be significantly reduced. Further, when it exceeds 2.0% by mass, the cuttability during cutting the glass strands deteriorates, and filament breakage occurs, resulting in a decrease in workability, which is not preferable. The loss on ignition is a value measured by a method according to JIS R 3420 (2023).

[0045] The glass strands of the present invention are manufactured, for example, by the following method. First, glass raw materials are charged into a glass melting furnace and heated to a temperature above the melting point of the glass to obtain molten glass. This molten glass is clarified and homogenized in a fining tank and formed (spun) into fibrous glass filaments using a bushing. The glass filaments are coated with a sizing agent for glass fibers on the surface, and a film derived from the solid components contained in the sizing agent for glass fibers is formed. A plurality of these are bundled and gathered to form glass strands. The glass strands are cut to a predetermined cut length and processed into chopped strands. The cutting of the glass strands may be an indirect method in which the glass strands are once wound around a collet to form a cake and then cut while unwinding the glass strands from the cake. However, in this embodiment, the following direct method is used.

[0046] Figure 1 is a schematic perspective view showing a method for manufacturing chopped strands by the direct method. In the manufacturing method by the direct method, first, a sizing agent for glass fibers is applied to the glass filaments GF drawn from the bushing 1 using an applicator 2. Subsequently, the glass filaments GF are divided into a predetermined number and gathered into a bundle by a gathering shoe 3 to form glass strands GS. Then, the glass strands GS are passed between a rotating cot 4 and a chopper 5, cut to a predetermined cut length, and the cut glass strands GS are conveyed by a conveyor 6 and dried in a drying furnace (not shown) to form a film on the surface of the glass fibers, thereby obtaining chopped strands. As the drying conditions at this time, for example, 140°C or higher and 200°C or lower are preferable, and 5 minutes to 15 minutes are preferable.

Example

[0047] Hereinafter, the present invention will be described in more detail based on examples. However, the following examples are merely illustrative. The present invention is not limited to the following examples at all.

[0048] [Example 1] (Preparation of Sizing Agent for Glass Fibers) 3% by mass of an aminosilane coupling agent, 64% by mass of an epoxy resin (weight average molecular weight 1000), 30% by mass of an isocyanate compound, and 3% by mass of an olefin resin (weight average molecular weight 3000) were mixed with water to prepare a sizing agent. As the aminosilane coupling agent, γ-aminopropyltrimethoxysilane was used. As the isocyanate compound, hexamethylene diisocyanate blocked with caprolactam (blocked isocyanate) was used. As the olefin resin, a polypropylene resin was used. (Production of glass fiber) Melted glass (composition: 62% by mass of SiO2, 17% by mass of ZrO2, 14% by mass of Na2O, 6% by mass of CaO, 1% by mass of TiO2) was drawn out from a bushing to obtain glass fiber. Next, the sizing agent was applied to the surface of the obtained glass fiber using an applicator, and dozens to hundreds of these glass fibers were gathered using a gathering shoe to form a glass strand with a count of 110 tex. Further, this glass strand was cut to a cut length of 12 mm using a chopper and a cott, and heat-dried in a hot air drying furnace to form a film on the glass fiber surface, thereby obtaining chopped strands. The loss on ignition of the obtained chopped strands was 1.6% by mass.

[0049] [Examples 2 - 3, Comparative Examples 1 - 3] Chopped strands were produced under the same operations and conditions except that the concentrations of the solid components of the aminosilane coupling agent, epoxy resin, isocyanate compound, and olefin resin were changed as shown in Table 1.

[0050] [Evaluation] (1) Density The density of the obtained chopped strands was measured using a graduated cylinder. (2) Binding property The bundling property of the obtained chopped strands was measured as follows. For a mortar composed of 10 kg of cement, 510 kg of silica sand, and 4.0 kg of water prepared with an omnimixer, GRC mortar mixed with 3% by mass of the chopped strands obtained in Examples 1 to 3 and Comparative Examples 1 to 3 was used, and a flow test of JIS R 5201 was carried out. Subsequently, the GRC mortar after the flow test was washed away with water, and only the chopped strands were taken out. The taken-out chopped strands were visually observed, and the bundling property was evaluated according to the following criteria. <Bundling property> A: The strands were not loosened at all (the shape was the same as before the test). B: Some of the strands were fibrillated. C: Most or all of the strands were fibrillated.

[0051]

Table 1

[0052] As is clear from Table 1, in Examples 1 to 3, where the content of the epoxy resin among the solid components in the sizing agent for glass fibers was 93% by mass or less and the content of the olefin resin was 0.5% by mass or more and 14% by mass or less, the density was as high as 0.25 g / cm 3 or more, the bulkiness was reduced, and it was also excellent in bundling property even after mixing with mortar. On the other hand, in Comparative Example 1 that does not contain a polyolefin resin, the density was as low as 0.2 g / cm 3 and it was bulky. Also, in Comparative Example 2 where the content of the polyolefin resin was more than 14% by mass, the bundling property was low, and in Comparative Example 3 where the content of the epoxy resin was more than 93% by mass, the density was as low as 0.22 g / cm 3 and the evaluation of the bundling property was also low.

Explanation of symbols

[0053] 1 Bushing 2 Applicator 3 Gathering shoe 4 Cot 5 Chopper 6 Conveyor GF glass filament GS glass strand

Claims

Claim 1 A sizing agent for forming a coating on the surface of glass fibers for a cement composite material, comprising: a solvent containing water and a solid component to form the coating, a sizing agent for glass fibers containing, per 100% by mass of the solid component, 93% by mass or less of an epoxy resin and 0.5% by mass or more and 14% by mass or less of an olefin resin. Claim 2 The sizing agent for glass fibers according to Claim 1, wherein the epoxy resin has a weight average molecular weight of 350 or more and 6000 or less. Claim 3 The sizing agent for glass fibers according to Claim 1 or 2, wherein the olefin resin has a weight average molecular weight of 500 or more and 5000 or less. Claim 4 The sizing agent for glass fibers according to Claim 1 or 2, wherein the solid component contains 5% by mass or more and 50% by mass or less of an isocyanate compound. Claim 5 The sizing agent for glass fibers according to Claim 1 or 2, wherein the isocyanate compound is a blocked isocyanate. Claim 6 A glass strand which is an aggregate of a plurality of glass fibers having a coating formed on the surface thereof, the coating being composed of the solid component in the sizing agent for glass fibers according to Claim 1 or 2. Claim 7 The glass fiber contains 12% by mass or more of ZrO ２ The glass strand according to claim 6, which contains 12% by mass or more of ZrO Claim 8 A cement composite material comprising the glass strand according to Claim 6.

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