Claims:CLAIMS
We claim:
A high adhesion layer coated glass fiber reinforced plastic (FRP) rod as strength member (105) for optical fiber cable (101), wherein the high adhesion layer coated glass FRP rod (105) comprises:
reinforcing fiber bundle(s) impinged with uncured acrylate based thermosetting resins to form a cured FRP rod (107), wherein the reinforcing fiber bundle(s) impregnated with resins cured by UV radiations; and
a high adhesion coating layer (104) composed of acid co-polymers, formed on an outer peripheral surface of the cured FRP rod (107).
The high adhesion layer coated glass FRP rod (105) as claimed in claim 1, wherein the high adhesion coating layer (104) composed of acid co-polymers comprises a minimum bending diameter of 10.0mm to 18.0mm based on the diameter of the FRP rod (107), a tensile strength greater than 140 kg/sq.mm, a flexural modulus greater than 5000 and an elongation at break in a range of 2.5%-4.0% with a minimum bending diameter reduced by 25% with a coating tolerance less than 40 µm.
The high adhesion layer coated glass FRP rod (105) as claimed in claim 1, wherein the high adhesion layer coated glass FRP rod (105) provides a diameter upto 1.5mm or less.
The high adhesion layer coated glass FRP rod (105) as claimed in claim 1, wherein the high adhesion coating layer (104) comprises a thickness of 10 µm- 50 µm.
The high adhesion layer coated glass FRP rod (105) as claimed in claim 1, wherein the reinforcing fiber bundle(s) comprises inorganic glass rovings wherein the inorganic glass rovings is one of E glass roving and H glass roving and wherein the reinforcing fiber bundle(s) provides an elastic modulus greater than 50Gpa and diameter of each fiber of the reinforcing fiber bundle(s) is in a range of 16.0 µm -18.0 µm.
The high adhesion layer coated glass FRP rod (105) as claimed in claim 1, wherein the acid co-polymers of the high adhesion coating layer (104) is one of acrylic acid and metha acrylic acid co-polymer with polyethylene, wherein the acid co-polymers comprises an acid content varying from 4.0%-15.0% and melt flow index (MFI) 5.0 g/min- 10.0 g/min.
A method of manufacturing high adhesion layer coated glass fiber reinforced plastic (FRP) rod (105) for optical cable (101), wherein the method comprises:
receiving reinforcing fibers (9) comprising inorganic glass rovings based on a diameter of the glass fiber reinforced rod,
obtaining a cured rod by drawing the reinforcing glass fibers (9) through an uncured acrylate based thermosetting resin bath comprising tension adjustment;
forming a high adhesion coating layer (104) composed of acid co-polymers on an outer peripheral surface of the cured rod;
obtaining the high adhesion layer coated glass FRP rod (105) by cooling the cured rod coated with the high adhesion coating layer (104) where the coating material is extruded and contacted with cured rod in a crosshead.
The method as claimed in claim 7, wherein the high adhesion coated layer (104) is provided by extruding a coating material in the melt state at a temperature in a range of 200? to 300 ? and wherein the cured rod (107) is brought in contact with the coating melt in a crosshead die.
The method as claimed in claim 7, wherein the resin bath comprises 1:1 to 1:5 ratio of resin to hardener along with at least 2.0%, photoinitator.
The method as claimed in claim 7, wherein the reinforcing glass fibers (9) is drawn through the resin bath at a processing speed of at least 70 mpm
The method as claimed in claim 7, wherein obtaining the cured rod by pultruding the reinforcing glass fibers (9) through the uncured acrylate based thermosetting resin bath comprising tension adjustment comprises:
passing the reinforcing glass fibers (9) through a die trough (12) comprising dies;
squeezing the reinforcing glass fibers (9) along with a resin to the specific diameter, wherein the die trough (12) is maintained at a temperature of 90 ?; and
imparting the specific diameter to each of the reinforcing glass fibers (9) to achieve an outer diameter of the glass fiber reinforced rod; and
obtaining the cured rod comprising the required outer diameter of the glass fiber reinforced rod.
The method as claimed in claim 7, wherein a diameter of the high adhesion coating layer coated glass FRP rod (105) is controlled by adjusting a die on an outer exist of the crosshead to vary a thickness of the resin between 10 µm-50 µm.
The method as claimed in claim 8, wherein the resin mixture tank to reinforce the reinforcing fibers (9) with thermosetting resins by UV curing comprises resin with a viscosity of 130 cp-2000 cp at temperature of 90 ? , and not less than2% photoinitator .
A high adhesion coating layer (104) for glass fiber reinforced plastic (FRP) rod (105) for optical fiber cable (101), wherein the high adhesion coating layer (104) comprises acid co-polymers, wherein the high adhesion coating layer (104) is formed on an outer peripheral surface of the cured FRP rod (105) and wherein the high adhesion coating layer (104) provides a minimum bending diameter of 10.0mm to 18.0mm based on a diameter of the FRP rod (105), a tensile strength greater than 140 kg/sq.mm, a flexural modulus greater than 5000 and an elongation at break in a range of 2.5%-4.0% with a minimum bending diameter reduced by 25% with a coating thickness less than 50 µm.
The high adhesion coating layer (104) as claimed in claim 14, wherein the diameter of the FRP rod (105) is upto 1.5mm and a thickness of the high adhesion coating layer (104) is in a range of 10 µm- 50 µm.
The high adhesion coating layer (104) as claimed in claim 14, wherein the acid co-polymers is one of acrylic acid and metha acrylic acid co-polymer with polyethylene, wherein the acid co-polymers comprises an acid content varying from 4.0%-15.0% and melt flow index (MFI) 5.0 g/10 min -15.0 g/10min.
An optical fiber cable (101) comprising a high adhesion layer coated glass fiber reinforced plastic (FRP) rod (105), wherein the high adhesion layer coated glass FRP rod (105) comprises:
reinforcing fiber bundle(s) impregnated with uncured acrylate based thermosetting resins to form a cured FRP rod (107), wherein the reinforcing fiber bundle(s) are cured by UV radiations; and
a high adhesion coating layer (104) composed of acid co-polymers, formed on an outer peripheral surface of the cured FRP rod (107).

, Description:
FORM 2
The Patent Act 1970
(39 of 1970)
&
The Patent Rules, 2005

COMPLETE SPECIFICATION
(SEE SECTION 10 AND RULE 13)

TITLE OF THE INVENTION

“High adhesion layer coated FRP rod for optical cable and method of manufacture thereof”

APPLICANTS:

Name : Runaya Private Limited

Nation : India

Address : Unit No. 412, 4th floor, The Capital, Plot No.
C70, G-block, Bandra Kurla Complex, Mumbai 400051.

The following specification particularly describes and ascertains the nature of this invention and the manner in which it is to be performed:-
FIELD OF INVENTION
The embodiments herein relate to fiber optical cable communication. More particularly relates to a high adhesion layer coated glass FRP rod as strength member for fiber optical cable and method of manufacture thereof.

BACKGROUND OF THE INVENTION
Generally, with advancement in information technology and increase in transmission information capacity such as internet, Fiber to the Home (FTTH) has rapidly progressed to install optical fiber cables to subscribers such as high-rise buildings and housing societies. Digital adoption is one of the primary tools by which nation can accelerate pace of development by better connectivity among citizens through e-government tools. Therefore, laying kilometers of optical fiber cable across different terrain is really challenging. Optical fibers have secured an important position in building network of modern telecommunication systems across world. The optical fiber cables are sensitive to conditions like crushes, bends, grooves and animal wiping’s. The optical fiber cables with high fiber optical count are more sensitive to bends, furthermore installation of optical fiber cables at sharp grooves requires large amount of bending. Due to the large amount of bending, compressive strains are generated inside the optical fiber cables which further create signal transmission losses. Further, the optical fiber cable with high fiber count has large diameter, and should have sufficient mechanical strength for protection of optical fiber which is embedded within from outside environmental factors. Embedding high adhesion glass fiber reinforced plastic (FRP) composite rod helps to achieve desired mechanical strength and also provides added advantage of the bending.
Fiber reinforced plastic rod is a common reinforcement to provide strength and durability in the fiber optic cable. However, compared to steel the glass FRP rods has various advantages such as lower installation costs, less maintenance, good insulator with low thermal conductivity, high dielectric capacity, weighs 75% less than steel and 30% less than aluminum and has lower lifecycle cost. The glass fiber reinforced FRP rods does not deform under impact, as the reinforced glass fibers in the composite distribute impact load to prevent damage even in subzero temperature, has better tensile properties along the transverse direction and resistance to a broad range of chemicals and unaffected by moisture. However, a stable and highly efficient, high adhesion coating for the glass FRP rods is required to enhance the performance of the reinforced glass FRP rod which are used as strength member in fiber optic cable. Thus, there is a need for bendable optical fiber cable that overcomes the above mentioned disadvantage which has high adhesion FRP embedded within it.

OBJECT OF INVENTION
The principal object of the embodiments herein is to provide a high adhesion layer coated glass FRP rod for optical fiber cable and method of manufacture thereof. The high adhesion layer coated glass FRP rod includes reinforcing fiber bundle(s) impinged with uncured acrylate based thermosetting resins to form a cured FRP with a high adhesion coating layer formed on an outer peripheral surface of the cured FRP. The high adhesion layer coated glass FRP rod can be used as strength member for the optical fiber cable and the high adhesion coating based glass fiber reinforced FRP rod can be manufactured with specified thickness by controlling thickness of high adhesion coating material and a final diameter of the high adhesion coating based glass FRP rod.
Another object of the embodiments herein is to provide a high adhesion coating using acid co-polymers. The high adhesion coating provides a minimum bending diameter of 10.0mm to 18.0mm based on a diameter of the FRP rod, a tensile strength greater than 140 kg/sq.mm, a flexural modulus greater than 5000 and an elongation at break in a range of 2.5%-4.0% with a minimum bending diameter reduced by 25% with a coating thickness less than 50 µm.

SUMMARY
Accordingly, the embodiments herein provide a high adhesion layer coated glass fiber reinforced plastic (FRP) rod as strength member for fiber optical cable. The high adhesion layer coated glass FRP rod includes reinforcing fiber bundle(s) impinged with uncured acrylate based thermosetting resins to form a cured FRP and a high adhesion coating layer composed of acid co-polymers, formed on an outer peripheral surface of the cured FRP. The reinforcing fiber bundle(s) impregnated with resins are cured by UV radiations.
In an embodiment, the high adhesion coating layer composed of acid co-polymers comprises a minimum bending diameter of 10.0mm to 18.0mm based on the diameter of the FRP rod, a tensile strength greater than 140 kg/sq.mm, a flexural modulus greater than 5000 and an elongation at break in a range of 2.5%-4.0% with a minimum bending diameter reduced by 25% with a coating thickness less than 50 µm.
In an embodiment, the high adhesion layer coated glass FRP rod provides a diameter upto 1.5mm.
In an embodiment, the high adhesion coating layer comprises a thickness of 10 µm- 50 µm.
In an embodiment, the reinforcing fiber bundle(s) comprises inorganic glass rovings wherein the inorganic glass rovings is of E glass roving and H glass roving available in varying TEX, and wherein the reinforcing fiber bundle (s) provides an elastic modulus greater than 50Gpa and diameter of each individual fiber of the reinforcing fiber bundle(s) is in a range of 16.0 µm -18.0 µm.
In an embodiment, the acid co-polymers of the high adhesion coating layer is one of acrylic acid or metha acrylic acid co-polymer with polyethylene, wherein the acid co-polymers comprises an acid content varying from 4.0%-15.0% and melt flow index (MFI) 5.0g/ 10 min -15.0 g/10 min.
Accordingly, the embodiments herein provide a method of manufacturing high adhesion layer coated glass fiber reinforced plastic (FRP) rod as strength member for fiber optical cable. The method includes receiving reinforcing fibers comprising inorganic glass roving’s tex based on diameter of the glass fiber reinforced rod and obtaining a cured FRP rod by drawing the reinforcing fibers through an uncured acrylate based thermosetting resin bath comprising tension adjustment. The method also includes forming a high adhesion coating layer composed of acid co-polymers on an outer peripheral surface of the cured FRP and obtaining the high adhesion coated glass reinforced FRP rod by coating the cured FRP with the high adhesion coating layer where the coating material is coextruded on the FRP rod through cross head die apparatus.
Accordingly, the embodiments herein provide a high adhesion coating for glass fiber reinforced plastic (FRP) rod for fiber optical cable, wherein the high adhesion coating comprises acid co-polymers, wherein the high adhesion coating is formed on an outer peripheral surface of the cured FRP and wherein the high adhesion coating provides a minimum bending diameter of 10.0mm to 18.0mm based on a diameter of the FRP rod, a tensile strength greater than 140 kg/sq.mm, a flexural modulus greater than 5000 and an elongation at break in a range of 2.5%-4.0% with a minimum bending diameter reduced by 25% with a coating thickness less than 50 µm.
Accordingly, the embodiments herein provide a fiber optic cable comprising a high adhesion coating based glass fiber reinforced plastic (FRP) rod used as strength member. The high adhesion coated glass FRP rod includes reinforcing fiber bundle(s) impregnated with uncured acrylate based thermosetting resins to form a cured FRP rod, wherein the reinforcing fiber bundle(s) along with resins are cured by UV radiations; and a high adhesion coating layer composed of acid co-polymers, formed on an outer peripheral surface of the cured FRP rod.
These and other aspects of the embodiments herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following descriptions, while indicating preferred embodiments and numerous specific details thereof, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the embodiments herein without departing from the scope thereof, and the embodiments herein include all such modifications.

BRIEF DESCRIPTION OF FIGURES
This invention is illustrated in the accompanying drawings, throughout which like reference letters indicate corresponding parts in the various figures. The embodiments herein will be better understood from the following description with reference to the drawings, in which:
FIG. 1A illustrates a high adhesion layer coated FRP rod used as strength member embedded in an fiber optical cable, according to the embodiments as disclosed herein;
FIG. 1B illustrates various layers of the high adhesion layer coated FRP rod, according to the embodiments as disclosed herein;
FIG. 2 is a schematic illustrating a UV pultrusion line for manufacturing the high adhesion layer coated based FRP rod used as strength member, according to the embodiments as disclosed herein;
FIG. 3 is a schematic illustrating a crosshead die and extruder comprising transducer to control pressure, die plate, and top and bottom base of crosshead, according to the embodiments as disclosed herein;
FIG. 4 is a schematic illustrating a pipe through which coating material flow above FRP, according to the embodiments as disclosed herein disclosed herein;
FIG. 5 illustrates an assembly of a crosshead die, according to the embodiments as disclosed herein;
FIG. 6 illustrates a direction of travel of the cured FRP through the crosshead die, according to the embodiments as disclosed herein; and
FIG. 7 is a flow chart illustrating a method of manufacturing the high adhesion coating based FRP rod as strength member for the fiber optical cable, according to the embodiments as disclosed herein.
DETAILED DESCRIPTION OF INVENTION
The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. Also, the various embodiments described herein are not necessarily mutually exclusive, as some embodiments can be combined with one or more other embodiments to form new embodiments. The term “or” as used herein, refers to a non-exclusive or, unless otherwise indicated. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein can be practiced and to further enable those skilled in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
As is traditional in the field, embodiments may be described and illustrated in terms of blocks which carry out a described function or functions. These blocks, which may be referred to herein as units or modules or the like, are physically implemented by analog or digital circuits such as logic gates, integrated circuits, microprocessors, microcontrollers, memory circuits, passive electronic components, active electronic components, optical components, hardwired circuits, or the like, and may optionally be driven by firmware. The circuits may, for example, be embodied in one or more semiconductor chips, or on substrate supports such as printed circuit boards and the like. The circuits constituting a block may be implemented by dedicated hardware, or by a processor (e.g., one or more programmed microprocessors and associated circuitry), or by a combination of dedicated hardware to perform some functions of the block and a processor to perform other functions of the block. Each block of the embodiments may be physically separated into two or more interacting and discrete blocks without departing from the scope of the invention. Likewise, the blocks of the embodiments may be physically combined into more complex blocks without departing from the scope of the invention
The accompanying drawings are used to help easily understand various technical features and it should be understood that the embodiments presented herein are not limited by the accompanying drawings. As such, the present disclosure should be construed to extend to any alterations, equivalents and substitutes in addition to those which are particularly set out in the accompanying drawings. Although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are generally only used to distinguish one element from another.
Accordingly, the embodiments herein provide a high adhesion layer coated glass fiber reinforced plastic (FRP) rod as strength member for fiber optical cable. The high adhesion layer coated glass FRP rod includes reinforcing fiber bundle(s) impregnated with uncured acrylate based thermosetting resins to form a cured FRP and a high adhesion coating layer composed of acid co-polymers, formed on an outer peripheral surface of the cured FRP. The reinforcing fiber bundle(s) and resins are cured by UV radiations.
Accordingly, the embodiments herein provide a method of manufacturing high adhesion layer coated glass fiber reinforced plastic (FRP) rod for fiber optical cable. The method includes receiving reinforcing fibers comprising inorganic glass rovings based on a diameter of the glass fiber reinforced rod and obtaining a cured FRP by pultruding the reinforcing fibers through an uncured acrylate based thermosetting resin bath comprising tension adjustment. The method also includes forming a high adhesion coating layer composed of acid co-polymers on an outer peripheral surface of the cured FRP and obtaining the high adhesion layer coated glass FRP rod by cooling the cured FRP coated with the high adhesion coating layer where the coating material is extruded and contacted with FRP in a crosshead die machine.
Accordingly, the embodiments herein provide a high adhesion coating for glass fiber reinforced plastic (FRP) rod as strength member for optical fiber cable, wherein the high adhesion coating comprises acid co-polymers, wherein the high adhesion coating is formed on an outer peripheral surface of the cured FRP and wherein the high adhesion coating provides a minimum bending diameter of 10.0mm to 18.0mm based on a diameter of the FRP rod, a tensile strength greater than 140 kg/sq.mm, a flexural modulus greater than 5000 and an elongation at break in a range of 2.5%-4.0% with a minimum bending diameter reduced by 25% with a coating thickness less than 50 µm.
Accordingly, the embodiments herein provide an fiber optical cable comprising a high adhesion layer coated glass fiber reinforced plastic (FRP) rod. The high adhesion layer coated glass FRP rod includes reinforcing fiber bundle(s) impregnated with uncured acrylate based thermosetting resins to form a cured FRP rod, wherein the reinforcing fiber bundle(s) and resins are cured by UV radiations; and a high adhesion coating layer composed of acid co-polymers, formed on an outer peripheral surface of the cured FRP rod.
In conventional fiber optical cables, FRP strength members generally have a round cross section. However, if the tension members are FRP there is a disadvantage that it is easy to break with a large bending diameter as compared to metal wire. Therefore to overcome the disadvantage, the proposed method includes using the acid co-polymer based coating having different composition for achieving high adhesion FRP rod. The percentage of the acid component mainly acrylic acid or metha acrylic acid modified polyethylene as the coating material having the acid composition varying form at least 5.0% but not more than 15.0% is used. Further, the method of manufacturing high adhesion glass fiber reinforced plastic rod with acid co-polymer coating, in which outer coating layer has a of thickness varying form 10 µm- 50 µm are formed on the cured FRP. The FRP rod formed can be used as strength member that are embedded in the jacketing material of the optical fiber cable helping in bending to smaller diameter and has excellent anti-shrinkage properties caused by better adhesion of FRP rod with the jacketing materials. Because of higher bending diameter on using larger TEX of glass fibers and products manufactured with those high TEX glass fibers, the proposed method uses bundle if low TEX glass fibers. When plurality of glass fibers are used, a bundle of glass fibers that are inherently low in TEX is expensive due to increase in the manufacturing cost, resulting in the increase in the cost of FRP rods. When multiple bundles of low tex reinforcing glass fiber bundles are used, there are problems of such as an increase in man-hours for uniform untwisting of glass fibers from the creel table, and difficulty in impregnations of the glass roving with the resin. In order to overcome these and specific application of development of smaller diameter strength members in the fiber optical cable, there was a need for invention of high adhesion, smaller diameter FRP since the surface area in contact with the jacketing material is less.
In the conventional manufacturing method related to coated glass fiber reinforced plastic rod, the coating material on the outer periphery of the FRP rod act as a “mold” until the uncured FRP is cured along with the coating material in the pressurized tank. Ovality (roundness) of the cured FRP rod needs to be maintained. When passing through the curing tank, the cured thin FRP may break as it hits the inner surface of the tank. Since the discharge amount of the coating layer decreases, at a higher production speed the cured FRP rod can break easily the coating and the cured FRP is easily affected by foreign matter and impurities in the cooling tank.
In the conventional methods of manufacturing of resin coated FRP rods, the surface of the coating layer is sized, but the accuracy of the outer diameter is determined by the surface roughness by a laser outer diameter measuring instrument. Further, to obtain such regular outer surface, a method of cutting the outer skin by passing a coated FRP strength member through a preheating die and shaping die is used. This setup requires long high-temperature steam curing tank where temperature has to be maintained at 150 ? , but due to severity in the process there are chances that coated material accumulates in the guide through which rod travels. This leads to coating breakage and decreases the yield of long products.
Unlike the conventional methods and systems, in the proposed method the high adhesion coating comprising of acid co-polymers is used. The reinforcing fiber bundle(s) are impregnated with an uncured acrylate based thermosetting resins and a coating layer composed of acid co-polymer is formed on an outer peripheral surface of the cured fiber reinforced plastic. The adhesion is quantitatively measured by bond strength between high adhesion FRP rod with the jacketing material used in fiber optical cable. The high adhesion layer coated glass FRP rod has a diameter 1.5mm or less and the coating layer has a thickness of less than 50 microns. The reinforcing fibers are inorganic E glass roving and H glass roving having elastic modulus more than 50Gpa and diameter of individual fiber varying from 16.0 µm -18.0 µm. The coating material used is acrylic acid or metha acrylic acid co-polymer with polyethylene having an acid content varying from 4.0%-15.0% and melt flow index (MFI) 5.0 g/min- 10.0 g/min.
In the conventional methods and systems, an approximately rectangular FRP string-like object coated with thermoplastic resin is provided. However, the bending capability of the rectangular FRP is very low and may break easily.
Referring now to the drawings, and more particularly to FIGS. 1 through 7, where similar reference characters denote corresponding features consistently throughout the figures, there are shown preferred embodiments.
FIG. 1A illustrates a high adhesion layer coated FRP rod used as strength member embedded in an fiber optical cable, according to the embodiments as disclosed herein and FIG. 1B illustrates various layers of the high adhesion layer coated FRP rod (105), according to the embodiments as disclosed herein. Referring to the FIG. 1A, the high adhesion coating based FRP rod (105) embedded in an optical cable (101) is provided. The high adhesion layer coated FRP rod (105) is used as a strength member. The optical fiber cable (101) includes buffer tubes (102) with the optical fiber (103) placed inside the buffer tubes (102). An outer periphery of the FRP rod (105) in which acid copolymer layer (104) is coated, interface with the polymer based jacketing material (106).
The high adhesion FRP rod (105) is formed in a circular cross-section with diameter not more than 1.5 mm is the FRP rod (105) is a composite made with thermosetting resin and having a coating material on the circumference. The coated FRP rod (105) is obtained by applying coating layer (104) on to the FRP, and the outer periphery of the FRP tensile body and the inner periphery of the coating layer are anchor-bonded to each other. The acid co-polymer coating on the outer periphery of the cured glass FRP rod (105) with thickness of coating layer not more than 50µm is manufactured at optimum line speed, better tolerance in the outside diameter of the cured fiber reinforced plastic rod, and a method of producing the same using a crosshead die installed in the production line. The method is as follows:
After impregnating a reinforcing fiber glass bundle with an uncured resin mixture and by UV curing method, coating material composed of acid co-polymer is formed on the outer periphery of the cured FRP rod. The coating is performed by the use of a crosshead die such that the coating uniformly wets the circumference of the cured FRP rod.
The acid co-polymer coated high adhesion FRP rod according to (1), has diameter 1.5 mm or less.
The acid co-polymer coated high adhesion FRP rod according to (1) or (2), wherein the thickness of the coating layer is 50 µm or less.
The acid co-polymer coated high adhesion FRP rod according to claim form (1) to (3), where in the acrylate based thermosetting resin diluted with UV curable acrylate, or diacrylate reactive diluent with photoinitator.
The acid co-polymer coated high adhesion FRP rod according to any one (1) to (4), wherein inorganic based E glass fiber having an elongation at break 0.6%-1.0% or more and elastic modulus more than 50 Gpa.
The acid co-polymer coated high adhesion FRP rod according to claim (1) to (5), where in the acid copolymer having acid content at least 5.0% but not more than 15.0% or a blend of different copolymers .
A reinforcing inorganic fiber bundle and mixture of resins are pultruded in to a predetermined shape to form a cured FRP rods, and is then coated. Finally, the coating resin incorporated high adhesion FRP rod is cooled and solidified. This invention eliminates the need for the pressurized steam curing tank to cure the coating material and final adjustment of the outer diameter of the coating layer.
The high adhesion FRP rod of the present invention can be effectively used as a strength member of optical fiber cable for countermeasures against animal attack, and provides sufficient mechanical strength. Further, the present invention reduces the thickness of the coating material, it is possible to reduce raw material costs, improve handling by reducing unit weight, reduce packing material costs, transportation costs, and storage costs. Furthermore, the production method of the present invention can manufacture long kilometer of high adhesion coated FRP rod having the above described characteristics, and can improve productivity and yield.
The acid copolymer includes acid content more than 4.0%, but not less than 15.0 % and includes the MFI less than 15 g/min. Application of a thin layer of the high adhesion coating layer (104) of thickness less than 50µm instead of a minimum thickness of several tens microns by allowing the interaction between the high adhesion coating material and the cured FRP rod in the crosshead die. Low MFI and/or low acid content are desirable in many dispersion applications. This is due to the fact that low MFI provides for properties such as improved scratch and abrasion resistance, and hot tack (seal strength), while low acid content provides for better adhesion to polymer substrates such as low density polyethylene (LDPE). Both the properties of the low MFI and the low acid content provides better chemical resistance to the high adhesion coating.
FIG. 2 is a schematic illustrating a UV pultrusion line for manufacturing the high adhesion layer coated FRP rod (105) used as strength member, according to the embodiments as disclosed herein. Referring to the FIG. 2, the method for producing the acrylic acid coated over the cured FRP is described. The glass roving’s as received are placed in a creel table (7,8). A required number of the reinforcing (9) inorganic glass roving’s selected according to diameter of the final cured glass fiber reinforced plastic rod, are impregnated in the thermosetting resin bath (10) having tension adjustment device (11) and pultruded through the die trough (12) which contains the dies by which the plurality of the glass fibers along with the resin is squeezed to specific diameter maintained at a temperature of 90 ?. Therefore, the outer diameter of the FRP portion is controlled.
The plurality of fibers is impregnated through the resin mixture tank (10) having viscosity 130cp-2000 cp, and photoinitator to reinforce the glass fibers with the thermosetting resins by UV curing. The mixture of reinforced fiber impregnated with thermosetting resin is pultrued through resin bath having 1:1 to 1:5 ratio of resin to hardener along with at least 2.0% of photoinitator and drawn at a higher processing speed of at least 70 mpm. The outer periphery of the uncured rod undergoes first dipping with the resin mixture in a bath (13), and the rod (14) is cured in a UV curing camber (15) which provides better surface and glossiness of the FRP outer periphery. The cured rod (14’) passes through a cooling bath tank (16) and an air stripper (17). The rod (14’) undergoes a second dipping through a resin bath (18) and cured in a UV chamber (19). The cured rod (14’’) is passed through the crosshead apparatus (20) which is passed through the UV chamber (22) and solidified in cooling tank (23) and the high adhesion rod (14’’’) is guided through dancer units (24) and collected in the spools (25). The outer periphery of the cured FRP filament (14’’) pultruded at a predetermined diameter is passed on through the crosshead (20) where the extruder coated material is made on to contact on the whole area of the cured FRP rods.
The coating material is extruded in the melt state at a temperature from 200?, but less than 300 ? . The cured FRP comes in to contact with the coating melt in the crosshead die. The high adhesion GFRP rod has excellent tensile strength > 140 kg/sq.mm, better flexural modulus > 5000 and has elongation at break 2.5%-4.0% with a minimum bending diameter reduced by 25% and the coating thickness less than 50 µm, and has high adhesion with jacketing material.
The diameter of the final coated material is controlled by adjusting the die on the outer exist of the crosshead (20) so that thickness of the coated resin varies from 10 um-50um. Furthermore, the coating material is preferably in a molten or in the melt state while the high adhesion coating material is in the crosshead in order to obtain an anchor adhesion with the FRP strength member. A high adhesion coating material having a melting point or softening point in the temperature of less than 100 ? more preferable.
FIG. 3 is a schematic illustrating a crosshead die and extruder comprising transducer to control pressure, die plate, and top and bottom base of crosshead,, according to the embodiments as disclosed herein. Referring to the FIG. 3, manufacturing apparatus of an extrusion of the high adhesion coating material and application of the high adhesion coating material via a crosshead is provided. Manufacturing apparatus (26) used for coating the high adhesion coating material is an adopter for the extruder with the crosshead, connected to the extruded body by half treaded blot (36). The high adhesion coating material is pumped through a pipe (29) and a pressure transducer (30) is provided for monitoring a flow rate of the high adhesion coating material. The pipe (29) is connected to crosshead body by dowel pins (35). The crosshead includes a base (31) and a cap (28). The base (31) and the cap (28) are bolted together by half treaded blots (27). The crosshead also includes a die plat (32) which are locked in to the crosshead body by locking plate (34) and half treaded blots (33) which are installed in the process line. The high adhesion coating material is applied on the outer periphery surface of the cured FRP through the die plat (32).
FIG. 4 is a schematic illustrating the pipe through which coating material flow above the FRP, according to the embodiments as disclosed herein. The assembly of the pipe with the lower base (31) of the crosshead. The high adhesion coating material flows into the crosshead through the groves, vertical section (38), and horizontal section (39) of the pipe.
Further, the FRP coated with the high adhesion coating material is passed through the cooling bath immediately and the high adhesion coating layer on the FRP is cured (14’’’) and the high adhesion coating layer solidifies. However, the reinforcing core position and the interface position of the high adhesion coating layer are softened upon coming in contact with the cooling bath.
The high adhesion FRP rod comprises a diameter of less than 1.5 mm and a minimum bend diameter of less than 20mm, which accounts for 25% less as per the specification of the minimum bend diameter. In addition, if the thermoplastic resin coating layer has a higher thickness, it becomes an impediment to flame retardance. Therefore, the coating layer preferably has a coating thickness of 10 µm to 50 µm.
FIG. 5 illustrates an assembly of the crosshead die, according to the embodiments as disclosed herein. The assembly of crosshead attached with the pipe extended from extruder which has holes beneath the pipes for coating material to flow above the incoming FRP rods as well as die plate attached outer surface for positioning dies to obtain the required coating thickness.
FIG. 6 illustrates a direction of travel of the cured FRP (14’’) through the crosshead die, according to the embodiments as disclosed herein. The figure shows the base attached with die plate where cured FRP rods enter into the crosshead for coating.
FIG. 7 is a flow chart (700) illustrating a method of manufacturing high adhesion layer coated glass fiber reinforced plastic (FRP) rod as the strength member (105) for the fiber optical cable (101), according to the embodiments as disclosed herein.
Referring to the FIG. 7, at step 702, the method includes receiving reinforcing fibers which includes inorganic glass rovings based on a diameter of the glass fiber reinforced rod.
At step 704, the method includes obtaining the cured FRP by pultruding the reinforcing glass fibers through an uncured acrylate based thermosetting resin bath comprising tension adjustment.
At step 706, the method includes forming a high adhesion coating layer (104) composed of the acid co-polymers on the outer peripheral surface of the cured FRP (105).
At step 708, the method includes obtaining the high adhesion layer coated glass FRP rod (105) by cooling the cured FRP rod coated with the high adhesion coating layer where the coating material is extruded and contacted with FRP in a crosshead.
The various actions, acts, blocks, steps, or the like in the method may be performed in the order presented, in a different order or simultaneously. Further, in some embodiments, some of the actions, acts, blocks, steps, or the like may be omitted, added, modified, skipped, or the like without departing from the scope of the invention.
Therefore, in the proposed method the high adhesion coating material composed of acid copolymer with different composition of both the acid content varying from 4.0% but less than 15.0% is used on the outer peripheral surface of the FRP rod (105) in a crosshead die which is followed with cooling and solidifying the high adhesion coating layer, impregnating a reinforced inorganic glass fiber with an uncured thermosetting resin by the UV pultrusion method, finally drawn in a specified diameter and collected in spools. The cured FRP rod is manufactured at a higher productivity rate and eliminates the need of complicated process setup for simultaneous coating and curing of FRP rods, with better control of the diameter of the FRP rods and has at least 70.0% fiber fraction but not more than 80.0% fiber volume fraction.
The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the scope of the embodiments as described herein.