CS224314B1 - Aqueous dispersion for preparing polymeric film for lubricating glass filaments or glass woven fabrics to be used in glass-cement compositions - Google Patents

Description

The present invention relates to an aqueous dispersion for the preparation of a polymer film for the lubrication of glass fibers and structures thereof, for use in glass-fiber composites. The water dispersion upon drying on the surface of the glass fibers forms a coating which optimizes the adhesion of the glass fibers to the cementitious binder and furthermore protects the fiber from alkaline corrosion of the cementitious compound.

The glass fibers themselves have insufficient initial adhesion to the cement, which increases over time but often at the expense of the strength of the fibers due to corrosion. Abroad, special glass fibers are used, resistant to alkaline corrosion, optionally lubricated from silane or polymeric materials. These lubricants protect the brittle fiber during handling against mechanical damage, keep the fiber strand together and increase the initial adhesion to the cement, eventually protecting the fiber from corrosion. Conventional vitreous fibers are not used for this purpose because they do not resist the alkaline environment of the cement and lose their reinforcing capacity completely in a very short time, for example in Portland cement within 120 to 200 days. The strength and durability of glass fiber cement composites are determined by the state at the interface between the glass surface and the matrix surface.

The aforementioned drawbacks are solved by a water dispersion for the preparation of a polymeric film for the lubrication of glass fibers or glass fabric for use in glass-cement composites, which comprises 1 to 10 wt. % copolymer of vinyl acetate with polyvinyl alcohol or vinyl acetate with alkyl esters having a carbon number of 2 to 10, or alkyl esters with styrene, 0.1 to 1.0 wt. % organofunctional silane and 0.1 to 1.0 wt. lubricants. The aqueous dispersion as vinyl acetate-alkyl ester copolymer preferably comprises vinyl acetate copolymer with butyl acrylate, octylacrylate

- 2,224,314 or diethylhexyl acrylate. As organofunctional silane it contains gamma-aminopropyltriethoxysilane, gamma-methacryloxypropyltrimethoxysilane, vinyl-tris / beta-methoxyethoxysilane. It contains oleic acid amide or paraffin or transformer oil as a lubricant. It is desirable to protect the glass strand with 0.8 to 2.0 wt% solids of polymer film based on the mass of glass and a glass cloth with 2.0 to 6.0 wt% solids based on the mass of glass.

The process of surface treatment of glass fibers by water dispersion according to the invention shows a greater initial, intermediate and final strength of the glass-fiber composite by interphase treatment and allows the use of less resistant glass fibers in combination with Portland cement or using less alkaline cement matrix such as high aluminate cement. This is achieved by using aqueous polymer dispersions such as

glass fiber lubricants based on polyvinyl acetate-polyvinyl alcohol copolymers, polyvinyl acetate with acrylates, for example butyl acrylate, ethylhexyl acrylate, acrylic acid, methacrylic acid, or these styrene acrylates. The aqueous dispersions are used in diluted form at a concentration of 1-10% by weight. To increase the adhesion of the polymer layer to the glass, hydrodizable organosilicon functional compounds such as gamma-aminopropyltriethoxysilane, gamma-methacryloxypropyltrimethoxysilane, vinyl tris / beta-methoxyethoxysilane and the like which, moreover, strengthen the fiber strand, which is stiffer and more flexible, which is advantageous when processing fibers with cement.

To prevent strands sticking during further processing of the fibers, a lubricant such as oleic acid amide, paraffin, transformer oil and the like is added to the aqueous dispersion in an amount of 0.1 to 1.0% by weight of the aqueous dispersion. This aqueous dispersion is applied to the fiber immediately after being pulled from the furnace. The surface treatment of the glass fibers by this aqueous dispersion significantly increases the strength of the glass-cement composites made therefrom. It has been found that this surface treatment also protects conventional glass fibers against the alkaline corrosion of cement.

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The subject matter of the invention is further described in some cases for guidance.

Example 1

Vodná? the dispersion for the preparation of the protective layer contained a / 500 ml and in an alternative example b / 600 ml of an aqueous dispersion of polyvinyl alcohol and butyl acrylate having a dry weight concentration of 50% and a pH of 4.8-6.0, 18 ml of gamma-aminopropyltriethoxysilane, ml 12.5% aqueous oleic acid amide solution was added to 5,000 ml with water. , '

Example 2 '·

The dispersion for the protective layer contained a / 500 ml b / 600 ml of an aqueous dispersion of polyvinyl alcohol and ethylhexyl acrylate at a weight concentration of 55% and a pH of 6.0. The other components were the same as in Example 1.

Example 5

The dispersion for the protective layer contained a / 500 ml b / 600 ml of an aqueous dispersion of polyvinyl acetate and polyvinyl alcohol at a concentration of 48% by weight and pH. 1.0 to 4.5. The other ingredients are the same as in Example 1.

Example 4

The dispersion for the protective layer contained a / 500 ml b / 600 ml of an aqueous dispersion of styrene and diethylhexyl acrylate at a weight concentration of 55% and a pH of 6.0. The other ingredients are the same as in Example 1.

The mixture of Examples 1-4 were prepared such that to the vessel to prepare a mixture with stirrer speed of 5,000 min ^"1 gradually metered -jednotlivé components as listed in a row. The dispersion is then stirred for 5 minutes and then used to lubricate the fibers, either directly in the fiber drawing process

For example, fabrics, mats, rovings and the like, or both, application techniques may be used.

-4 224 314

The glass fibers / fabrics / after application of the lubricant are heat treated at a temperature of 90 to 150 ° C, the dry state of the polymer film when applied to the sliver is 0.5 to 2.0% and when applied to the fabrics 2.0 to 6, 0%, based on the weight of the glass.

The lubrication according to Examples 1-4 was applied to mechanically drawn glass fibers from a 400 single-stage jet furnace under operating conditions. The fiber diameter was about 11 µm.

Each blend was agitated for 5 minutes with a 5000 rpm stirrer, the dispersion was poured into a flask with a bottom at the bottom, and the hose was fed into a bowl under a roller through which freshly drawn glass fibers were routed to the winding device. Wound glass fiber disks were stored for 6 hours in an oven at 12 ° C to evaporate solvents and dry the lubrication. Thanks to the oleic acid lubricant, the fiber strand was easily unwound and the individual strands did not stick together. Due to the action of gamma-aminopropyltriethoxysilane, adequate stiffness and elasticity of the strand were obtained, which is advantageous in the treatment of fibers with a cementitious mixture.

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The fiber strand was chopped to lengths of 55 mm and 80 mm and composite beams were formed with conventional Portland cement, 20x20x100 mm, with a 3% volume of 80 mm unidirectionally oriented beam length, and a thin plate with bi-directional random arrangement of fibers making up 3.6% volume. For freshly manufactured composite samples, external vibrations were used to vibrate the air bubbles and obtain greater compactness. The samples were stored for 24 hours in saturated water vapor and then in water at room temperature. Resistant enamel and drastic water storage conditions were deliberately used to show the effect of fiber surface treatments as soon as possible. These specimens were tested for flexural tensile strength after 28, 90, 120, 210, 360 days of deposit, and compressive strength on the remainder of the beams at these time intervals. These strengths were compared with those of unreinforced cement prepared under the same conditions and with strengths of

224,314 samples with a fiber lubricated by the commonly used .026 lubrication containing, inter alia, components that should to some extent protect the glass surface from corrosion by alkali. The glass composition is given in Table 1, the properties of Portland cement in Table 2 and the results of the strengths in Tables 3, 4, 5. It should be noted that the loss in flexural strength of wet laid comppoeite beams made of alkaline fibers or even less corrosive high aluminous cement in the period of 4 weeks and 6 months the deposit is about 50% due to microstructural changes at the glass-cement interface, when the fiber is not yet corroded and has no noticeable decrease in strength.

The comparison shows that the lubrication of Example 1 a, b, a, b, 3 a, b protect the fibers from corrosion and contribute to increasing the initial, continuous and final strengths of the composites, according to Example 4 a, b, the lubrication achieves lower strengths but protects the fiber from corrosion.

TABLE 1

Weight composition of glass:

SiO ₂ 52%, CaO 17%, Na ₂ 0 1.0%, K ₂ 0 1.0%, BgO 3 9.0%, Al ₂ 0 ₅ 16.0%, MgO 4.0%.

TABLE 2

The properties of portland cement composition by weight: _SiO2 20.36%, A1 ₂ 0j 5.00 Fe ₂ O-2.50%;

CaO 63.35%, MgO 2.01%, SO ₅ 3.18% loss on ignition 0.97% insoluble residue 1.43% fineness of grinding: residue on sieve 0.2 in% i 0.4 residue on sieve 0, 09%: 6.8

Blein specific surface area cm @ 3 / g 3177

Solidification: start 2.5 h end 4.10 h

TABLE 3

Bending tensile strength, wet fit, 3% fiber volume, mm long beam dimensions 20x2-0x100 mm, three-point load,

- 6224 314 support distance 80 mm, crosshead travel speed 21 mm / min.

end- marking days of storage clade trace lubrication 28 50 1Σ0 210 3é0

1 and/ polyvinyl alcohol, 44.4 43.4 40.6 27.2 20.4 butyl acrylate MPa MPa MPa MPa MPa b / H 39.8 46.7 36.3 28.5 22.9 2 and/ polyvinyl alcohol, ethylhexyl acrylate 41.4 31.3 35.2 28.2 25.0 b / « 39.2 39.3 35.1 27.8 23.9 3 and/ polyvinyl acetate, polyvinyl alcohol 42.0 42.6 54.1 26.2 21.0 b / H 4 and/ styrene, diethylhexyl acrylate 43.3 36.8 31 20.4 16.8 b / H 36.7 33.2 27.4 25.9 19.5 026 35.4 27.2 20.4 24.8 16.05 without fibers 11.3 12.8 12.5 12.4 12.0

TABLE 4

Compressive strength, load shifting speed 2 mm / min

klad trace lubrikace 28 90 120 210 360 1 and/ polyvinyl alcohol, 68.8 79.3 88.7 90.5 100.6 butyl acrylate MPa MPa MPa MPa MPa b / M 85.5 83.7 95.5 92.3 99.4 2 and/ polyvinyl alcohol, ethylhexyl acrylate 66.5 86, 84.3 85.3 90.6 b / 67.5 72.8 88.8 87.1 95.0 3 and/ polyvinyl acetate, polyvinyl alcohol 57.3 82.9 78.8 90.4 91.2 b / »1 4 and/ styrene, diethylhexyl acrylate 48.5 57.5 55.8 71.3 65.6 b / 47.8 51.6 62.5 65.4 62.2 026 58.2 48.5 47.7 67.9 65.9 without fibers 60.5 66.3 77.5 89.2 96.1

- 7 TABLE 5

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Flexural tensile strength, 5,4% vol. mm, beam dimensions 20x20x100 mm, three-point load, support distance 80 mm, crosshead travel speed 21 mm / min finished - marking _ days of storage

klad trace and lubrication 28 90 120 210 560 1 and/ polyvinyl alcohol, 21.0 22.0 15.8 15.8 butyl acrylate MPa MPa MPa · MPa ' b / 19.5 19.4 17.02 11.5 3 and/ polyvinyl acetate polyvinyl alcohol 16.1 21.5 17.9 11.7 2 b / polyvinyl alcohol, 20.6 20.9 20.4 18.8

Fiber-free ethylhexyl acrylate _t

Claims (4)

1. Water? Dispersion for the preparation of a polymer film for the lubrication of glass fibers or glass fabrics, for use in glass-cement composites, characterized in that it comprises 1 to 10% wt. % copolymer of vinyl acetate with polyvinyl alcohol or vinyl acetate with alkyl esters having a carbon number of 2 to 10, or alkyl esters with styrene, 0.1 to 1.0 wt. % organofunctional silane and Oj up to 1.0 wt. lubricants. 2. Water? The dispersion of claim 1, wherein the vinyl acetate / alkyl ester copolymer is a vinyl acetate copolymer with butyl acrylate, octyl acrylate or diethylhexyl acrylate. Aqueous / dispersion according to Claims 1 and 2, characterized in that the organofunctional silane is gamma-aminopropyltriethoxysilane, gamma-methacryloxypropyltrimethoxysilane, vinyl-tris / beta-methoxyethoxysilane. S 8 » 4. An aqueous dispersion according to claim 1, wherein the lubricant is oleic acid amide or paraffin or trafoil. '