Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
  • C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
  • C08L23/04—Homopolymers or copolymers of ethene
  • C08L23/08—Copolymers of ethene
  • C08L23/0846—Copolymers of ethene with unsaturated hydrocarbons containing other atoms than carbon or hydrogen atoms
  • C08L23/0869—Acids or derivatives thereof
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B16/00—Use of organic materials as fillers, e.g. pigments, for mortars, concrete or artificial stone; Treatment of organic materials specially adapted to enhance their filling properties in mortars, concrete or artificial stone
  • C04B16/04—Macromolecular compounds
  • C04B16/06—Macromolecular compounds fibrous
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B16/00—Use of organic materials as fillers, e.g. pigments, for mortars, concrete or artificial stone; Treatment of organic materials specially adapted to enhance their filling properties in mortars, concrete or artificial stone
  • C04B16/04—Macromolecular compounds
  • C04B16/06—Macromolecular compounds fibrous
  • C04B16/0616—Macromolecular compounds fibrous from polymers obtained by reactions only involving carbon-to-carbon unsaturated bonds
  • C04B16/0625—Polyalkenes, e.g. polyethylene
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
  • C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
  • C08L23/10—Homopolymers or copolymers of propene
  • C08L23/12—Polypropene
• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
  • D01F6/00—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof
  • D01F6/28—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from copolymers obtained by reactions only involving carbon-to-carbon unsaturated bonds
  • D01F6/30—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from copolymers obtained by reactions only involving carbon-to-carbon unsaturated bonds comprising olefins as the major constituent
• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
  • D01F6/00—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof
  • D01F6/44—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from mixtures of polymers obtained by reactions only involving carbon-to-carbon unsaturated bonds as major constituent with other polymers or low-molecular-weight compounds
  • D01F6/46—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from mixtures of polymers obtained by reactions only involving carbon-to-carbon unsaturated bonds as major constituent with other polymers or low-molecular-weight compounds of polyolefins
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L2203/00—Applications
  • C08L2203/12—Applications used for fibers

Definitions

• the invention relates to a polyolefin-based material for fiber, the fibers made thereof being usable for the manufacture of durable and tough concrete products.
• fibers made of materials of different types for modifying the properties of concrete and cement. Such fibers are used, for example, for improving the toughness properties and durability of concrete, for preventing the formation of cracks, and also as a so-called reinforcement material. It is known to use, for example, steel and iron rods for reinforcing concrete structures. In addition, setting accelerators, compressive-strength promoters, etc. , are used in concrete materials.
• the present invention relates specifically to those materials used for modifying concrete the use of which decreases the formation of deleterious cracks in concrete, and owing to this lower number of cracks the effects of water, salt and other materials which disintegra ⁇ te concrete remain less, and thus a more durable and tougher concrete material is ob ⁇ tained.
• Concrete material is in itself a moisture-containing and also alkaline material.
• Many fibers which under normal conditions have good and desirable properties for modifying concrete cannot, however, be used as such in moisture-containing and alkaline concrete material. This is due not only to the absent or slight hydrophilic quality of the fibers, i.e. they do not sufficiently well adhere to or become dispersed into concrete, but also to the fact that alkaline and moist conditions weaken the mechanical properties of the fibers.
• the fibers used for the modification of concrete thus should be hydrophilic in character in order to be capable of adhering to and becoming dispersed into the concrete matrix as well as pos ⁇ sible.
• the fibers should have mechanical properties which are good for the intended use and remain good despite the moisture content and alkalinity of the concrete.
• the disadvantage of known fibers previously used for the modification of concrete has been either the absence of hydrophilic quality in fibers having good mechanical properties or the absence of the desired mechanical properties in hydrophilic fibers, or the deteriora ⁇ tion of these qualities in moist and alkaline conditions.
• Fibers hydrophobic in character, such as polypropylene fibers have properties good for the modification of concrete, such as alkali resistance, tensile strength and rigidity properties which are almost independent of the moisture content, i.e. stable, and an economical price.
• the volume/weight ratio of polypropylene fibers is excellent.
• EP patent publication 0 026 581 discloses a method for improving hydrophilic quality by adding inorganic particles to a molten polymer, such as polypropylene.
• carboxylic acid groups or anhydride groups are added to an organic polymer material from which fibers are to be produced, such as polyolefins, for example polypropylene, by modifying the polyolefin.
• polyolefin is modified with silane compounds in order to achieve better adhesion to a concrete material.
• US patent publication 4,801,630 proposes as a concrete reinforcement material a modified polyolefin resin composition from which fibers can be prepared and which comprises 90- 99 % by weight of an olefin polymer, such as polypropylene, and 10-1 % by weight of a modifier mixed with polyolefin.
• the modifier for its part is a reaction product of a vinyl alcohol copolymer, e.g. vinyl alcohol ethylene copolymer, and an acid-modified, e.g. maleic acid anhydride modified, polypropylene.
• the method according to PCT application publication 90/06902 proposes the dispersing of fibers into a cement material in the form of fiber bundles comprising 10-10000 strands having a length of approx. 1-30 mm and a diameter of approx. 5-50 ⁇ m.
• the fiber material is, for example, polyolefin, such as polypropylene.
• the strands in the fiber bundles have on their surface a wetting agent which promotes their dispersion into the cement material.
• the methods described above have the disadvantage that the fibrillation process is difficult to control owing to the required filler particles or to bridging and melt index changes as a secondary reaction of the functionalization process.
• the wetting agent on the surface of the strands is not covalently bound to the fibers, and so it is possible that the hydrophilic quality of the material disappears.
• the invention relates to a polyolefin-based fiber material which is characterized in that it contains co- or terpolymers which contain hydrophilic groups.
• the fibers made of a polyolefin-based fiber material according to the invention are hydrophilic fibers, easily dispersible into a concrete material, and additionally they have good mechanical properties and good adhesion to a concrete matrix.
• fibers made from the fiber material according to the invention retain well their properties in the moist and alkaline conditions of concrete.
• cement-based materials fibers which have been made of a polyolefin-based fiber material according to the invention, concrete products are obtained which are durable and tough and in which significantly fewer detrimental cracks are formed as compared with prior-known methods for the modification of cement-based products.
• the present invention thus relates to a polyolefin-based fiber material in the main made up of olefin polymers among which at least one polymer contains hydrophilic groups.
• hydrophilic groups may be, for example, hydroxy groups and epoxy groups.
• active nitrogen groups can serve as hydrophilic groups.
• preferred monomers which contain hydrophilic groups and form co- or terpolymers with olefins are (meth)acrylates, (meth)acrylamides, and their derivatives.
• the (meth)acrylates which contain hydrophilic groups are, for example, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, 2,3-epoxypropyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, and tert-butylaminoethyl (meth)acryla- te.
• the third monomer type may preferably be, for example, vinyl acetate or alkyl (meth)acrylate.
• hydrophilic polymer may be compounded with other polymers.
• polymers which have good mechanical properties (such as good tensile strength properties) and stable properties.
• Such polymers are often hydrophobic in character.
• hydrophilic polymer with a hydropho- bic polyethylene, in particular a high-density polyethylene (HDPE), polypropylene, poly- 1-butene, poly-4-methyl-l-pentene, or a polyolefin/polyamide or polyolefin/polyalkene terephthalate mixture.
• the compounding can be carried out by a melt-spinning, melt- mixing or coextrusion method. In this manner the good adhesion and dispersion properties of a hydrophilic polymer can be combined with the good and stable mechanical properties of a hydrophobic polymer.
• the fibers can thus be made, for example, from a multi-layer film produced by coextrusi- on or from a single-layer film produced by the melt-mixing method.
• processing methods and conditions are used by means of which as good a hydrophilic quality, i.e. a high concentration of hydrophilic olefin polymer, is obtained for the surface layers of the fiber.
• a hydrophilic quality i.e. a high concentration of hydrophilic olefin polymer
• the multi-layer films have been extruded in such a manner that the surface layers consist of a hydrophilic polymer and the core layer of a hydrophobic polymer.
• a hydrophobic polymer can be selected for the core layer and a hydrophilic polymer for the surface.
• a one-component melt-spinning technique is used, a lower viscosity is selected for the desired surface polymer than for the polymer remaining in the inner parts.
• a lower-viscosity polymer migrates by itself to the surface of a fiber material, whereby the desired polymer type is also obtained for the surface of the completed fiber.
• the size of the cracks decreases even to one- eighth when fibers made from a fiber material according to the invention are used as compared with the use of commercial fibers (cf. Example 3). Furthermore, fibers made from a material according to the invention have good miscibility with a concrete matrix. This can be measured and demonstrated, for example, by measuring the variation of the power requirement of the mixer (cf. Example 4).
• fibers made from an olefin-based fiber material according to the invention containing hydrophilic groups, are highly dispersible into and adherent to a concrete matrix and give concrete good toughness and durability properties.
• the core layer used was a polypropylene by trade name NESTE POLYPROPYLENE VB19 50K having a melt index of 1.9 (230 °C/- 21.6 N).
• Ethylene co- and terpolymers containing hydroxyl groups, or mixtures of these with polypropylene, were used as the surface layers.
• the material of the surface layers was the same on both sides of the film. The materials of the surface layers are shown in Table 1.
• the comonomer of the hydroxyfunctional ethylene copolymer in the table is 2-hydroxyethyl methacrylate, and its concentration in the copolymer is 8 % by weight.
• the melt index of the ethylene copolymer is 1.5 (190 °C/21.6 N).
• the ter- monomers of the hydroxyfunctional ethylene terpolymer are 2-hydroxyethyl methacrylate, concentration 9 % by weight, and vinyl acetate, concentration also 9 % by weight.
• the melt index of the ethylene terpolymer is 1 (190 °C/21.6 N). Table 1. Materials of the surface layers of the films
• VB19 50K Neste Polypropylene VB19 50K
• F6 is, deviating from films F1-F5, a single-layer film, i.e. the materials of the film have been melt mixed in a twin-screw extruder, whereafter the obtained compound has been run into a single-layer film.
• the films were heated with hot air and stretched at a stretching ratio 1:14, whereafter the films were shredded in the longitudinal direction and cut into fibers 12 mm long.
• Fibers made in Example 1 were mixed with concrete in a Hobart mixer.
• the concrete had been prepared by using water, Portland Rapid cement manufactured by Lohja Oy, and aggregate (DIN 1164) at the ratio of 1:2:6.
• the proportion of fibers in the concrete was 0.9 % by weight.
• the toughness index I 30 of the obtained fiber-reinforced concrete was measured 7 days after the casting, in accordance with the ASTM C1018 standard (relative humidity 100 %, temperature 20 °C).
• Table 2 shows the concrete toughness indices I 30 achieved with the use of fibers F1-F6 made from materials according to the invention and, for comparison, the corresponding values achieved with the use of the commercial fibers Hoechst's Dolanit, Danaklon's Crackstop and Krenit Special.
• Example 3 Measuring of cracks formed in the concrete.
• the susceptibility of concrete prepared according to Example 2 and containing 0.025 % by weight of fibers to crack under constraint action was investigated by casting a sample in a circular mold, a diagram of which is shown in Figure 1.
• Reference numeral 1 indicates the concrete layer in the mold, the thickness of the layer being 30 mm;
• numeral 2 indicates the steel ring, thickness 20 mm.
• the total diameter of the circular mold is 270 mm and its width 40 mm.
• the concrete samples contained the following fibers: a) reference, no fibers, b) Dolanit 10, c) Krenit Special, d) Crackstop, e) FI (cf. Example 1), and f) F4 (cf. Example 1).
• the molds were stored at a relative humidity of 40 % and a temperature of 20 °C for 35 days, whereafter the mean size of the cracks formed in the concrete layer was measured. Furthermore, the sizes of cracks in each sample were added together, and thus the total size of the cracks was obtained. The results are shown in Table 3. Table 3. Mean size of single cracks in the concrete samples and the total size of cracks.
• Example 4 Dispersibility of the fibers into a concrete matrix.
• the dispersibility of the fibers into a concrete matrix was investigated by measuring the variation of the power intake of the mixer during the mixing.
• the composition of the concrete was the same as in Example 1, and the mixer used was the same as in Example 2.
• the measurements were performed on commercial fibers Krenit Special, Crackstop and Dolanit 10, and on fiber F3 made from a fiber material according to the invention.
• the fiber concentrations used in the concrete samples were 0.05 % by weight, 0.15 % by weight, and 0.5 % by weight.
• the concrete was mixed first before the adding of the fibers, at which time there is no variation (noise) in the power requirement of mixing, but after the adding of the fiber there are differences in the variation of the power requirement of the mixer.
• Figures 2a-2d depict various variations in the power intake of the mixer.
• Figure 2a depicts a sample which contains fiber F3 made of a fiber material according to the invention
• Figure 2b depicts a sample containing Krenit Special fiber
• Figure 2c a sample containing Crackstop fiber
• Figure 2d a sample containing Dolanit 10 fiber.
• the amount of noise is thus proportional to the power requirement variation, which for its part correlates inversely with the dispersibility of fiber into concrete.
• a low variation (noise) in the mixing power requirement indicates a good dispersibility of the fiber into concrete.
• Figures 2a-2d show clearly that the lowest noise, i.e. the best dispersibility, is achieved with fiber F3 made of a fiber material according to the invention, at all the concentrations.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Ceramic Engineering (AREA)
• Organic Chemistry (AREA)
• Textile Engineering (AREA)
• Health & Medical Sciences (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• General Chemical & Material Sciences (AREA)
• Materials Engineering (AREA)
• Structural Engineering (AREA)
• Curing Cements, Concrete, And Artificial Stone (AREA)
• Artificial Filaments (AREA)
• Treatments For Attaching Organic Compounds To Fibrous Goods (AREA)

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Cited By (6)

Citations (6)

• 1993
  • 1993-03-12 FI FI931099A patent/FI92337C/fi not_active IP Right Cessation
• 1994
  • 1994-03-08 WO PCT/FI1994/000082 patent/WO1994020654A1/en active Application Filing

Patent Citations (6)

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