DESC:FIELD OF INVENTION:
The present invention is an improvement over the composite product claimed in Patent Application No. 201621020446 filed on June 15th, 2016.
The present invention relates to a honeycomb closed cellular composite product having a robust impact resistance. The product consists of essen¬tially multiple layers of a synthetic polyester felt impregnated with a resin system and multiple layers of a bi-directionally and a uni-directionally oriented synthetic fabric, particularly synthetic glass fabric impregnated with a resin system arranged to form a core and an encapsulated layer; the core comprising non-spaced-apart closed cellular polygonal columnar units, particularly hexagonal columnar units stacked alongside one another to fill the void of the core; thereby the product is having at least 50 % void vol./vol. and also is having robust impact resistance yet being a low cost and a light weight product.
It also relates to a pultrusion method for the production of the honeycomb closed cellular composite product; wherein said method reduces manufacturing cost as it uses waste plastic, reduces environmental impact and improves the impact resistance of the composite product with high endurance in adverse environmental conditions.
It also relates to the honeycomb closed cellular composite product having properties namely, robust impact resistance, low stress, shock-proof, and can be utilised in the applications such as aerospace, automotive, construction, and to impede impactor or projectiles travelling at high speed, etc.

BACKGROUND OF THE INVENTION:
The present Indian Patent Application relates to Indian Patent Application No. 3985/MUM/2015 filed on 21st Oct 2015 and Indian Patent Application No. 201621020446 filed on 15th Jun 2016. The prior art references mentioned therein, the composite product and the system, and the pultrusion process for continuous production of the composite pultruded prod¬uct from the said Patent Applications are incorporated herein entirety as reference.
The honeycomb structural material is commonly made by layering honeycomb cells between two thin layers forming a plate-like assembly. These materials are well known for their high specific strength and they are widely used in the aerospace industry for this reason. They are commonly made from materials like aluminum, fiberglass and advanced composite materials have been featured in aircraft and rockets since the 1950's.
The basic advantage of geometry of honeycomb is the use of minimum material for the construction leading to light weight product and reducing the cost substantially. A honeycomb shaped structure provides a material with minimal density and relatively high out-of-plane compression properties and out-of-plane shear properties.
Expansion, Corrugation, and Molding are the three traditional honeycomb production techniques for non-sandwich applications since 1901. Today honeycomb cores are manufactured via the expansion process and the corrugation process from composite materials such as glass-reinforced plastic (also known as fiberglass), carbon fiber reinforced plastic, Nomex aramide paper reinforced plastic, or from a metal (usually aluminum).
Honeycombs from metals (like aluminum) are today produced by the expansion process. Continuous processes of folding honeycombs from a single aluminum sheet after cutting slits had been developed already around 1920 (US1389294). Continuous in-line production of metal honeycomb can be done from metal rolls by cutting and bending. However, the aluminum honeycomb is heavy or bulky and is having poor impact resistance to high speed impactor or projectile. Thus, may not be sufficient to be used in aerospace, automotive, construction, etc.
Thermoplastic honeycomb cores (usually from polypropylene) are usually made by extrusion process via a block of extruded profiles or extruded tubes from which the honeycomb sheets are sliced.
The composite product disclosed in Indian Patent Application No. 201621020446 filed on June 15th, 2016 has impact strength in the range of 50 to 79 Mpa. This is not sufficient for certain applications which needs to impede impactor or projectile travelling at high speed or in aerospace, automotive, construction, etc.
Accordingly, there is a long felt need to develop the honeycomb closed cellular product having the robust impact resistance yet being light weight and lower in cost. There is also a long felt need to develop a fast and simple, yet technically improved and economically significant method of producing the honeycomb closed cellular composites with improved products having uniform mechanical property, light weight with enhanced tensile and bending strength and robust impact resistance subject to dynamic application including impeding impactor or projectile travelling at high speed or aerospace, or automotive or construction, etc.
According to our knowledge, there is no composite product similar to the honeycomb closed cellular composite product having the robust impact resistance, which consists of essen¬tially multiple layers of the synthetic polyester felt impregnated with the resin system and multiple layers of the bi-directionally and the uni-directionally oriented synthetic fabric, particularly the synthetic glass fabric impregnated with the resin system arranged to form the core and the encapsulated layer; the core consisting of non-spaced-apart closed cellular polygonal columnar units, hexagonal columnar units stacked alongside one another to fill the void of the core; thereby the product is having at least 50 % void vol. per vol. and also having robust impact resistance yet being low cost and light weight. According to our knowledge, there is no existence of a continuous or a batch pultrusion method for a production of the honeycomb closed cellular composite product of the present invention.

OBJECTS OF THE INVENTION:
An object of the invention is to provide a honeycomb closed cellular composite product having a robust impact resistance yet being light weight and low cost.
Another object of the invention is to provide the honeycomb closed cellular composite product which utilizes waste plastics or polyester.
Another object of the invention is to provide the honeycomb closed cellular composite product consisting of essen¬tially multiple layers of a synthetic polyester felt impregnated with a resin system and multiple layers of a bi-directionally and a uni-directionally oriented synthetic fabric impregnated with a resin system arranged to form a core and an encapsulated layer; particularly the core comprising non-spaced-apart closed cellular polygonal columnar units, hexagonal columnar units stacked alongside one another to fill the void of the core; thereby the product is having at least 50 % void vol. /vol. and having robust impact resistance yet being low cost and light weight.
Another object of the invention is to provide the honeycomb closed cellular composite product comprising the hexagonal columnar units stacked alongside one another as well as stacked height-wise, to form a plurality of layers, such that they pack the core in its entirety.
Yet another object of the invention is to provide the honeycomb closed cellular composite product that reduces environmental impact.
Still another object of the invention is to provide the honeycomb closed cellular composite prod¬uct with improved low ratio of weight to strength.
Yet still another object of the invention is to provide the honeycomb closed cellular composite prod¬uct eliminating use of conventional glass roving and overcoming the limitation of jamming of glass roving in resin bath.
Yet still another object of the invention is to provide the honeycomb closed cellular composite prod¬uct with robust impact resistance and its use in dynamic applications including impeding impactor or projectile travelling at high speed or in aerospace, automotive or construction, etc.
Additional object of the invention is to provide a continuous or a batch pultrusion method for production of the honeycomb closed cellular composite prod¬uct with robust impact resistance; said process is reducing manufacturing cost, reducing environmental impact and improving composite product, which can be used in dynamic applications including impeding impactor or projectile travelling at high speed or in aerospace, automotive or construction, etc.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS:
Figure 1 illustrates a profile of the honeycomb closed cellular composite prod¬uct.
Figure 2 illustrates a cross-section view of the profile of the honeycomb closed cellular composite prod¬uct.
Figure 3 illustrates a pultrusion apparatus for a continuous or a batch production of the honeycomb closed cellular composite product; particularly profiles as shown in Fig.1 and Fig. 2.
Figure 4 illustrates an exploded view of the pultrusion die having floating mandrel.

DETAILED DESCRIPTION OF THE INVENTION:
The present invention as described below, it is to be understood that this invention is not limited to particular embodiments, drawings, methodologies and materials described, as these may vary as per the person skilled in the art. It is also to be understood that the terminology used in the description is for the purpose of describing the particular embodiments only and is not intended to limit the scope of the present invention.
Before the present invention is described, it is to be understood that unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Further, it is to be understood that the present invention is not limited to the methodologies and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, the preferred methods and materials are described, as these may vary within the specification indicated. Unless stated to the contrary, any use of the words such as "including," "containing," "comprising," "having" and the like, means "including without limitation" shall not be construed to limit any general statement that it follows to the specific or similar items or matters immediately following it. Embodiments of the invention are not mutually exclusive, but may be implemented in various combinations. The described embodiments of the invention and the disclosed examples are given for the purpose of illustration rather than limitation of the invention as set forth the appended claims. Further the terms disclosed embodiments are merely exemplary methods of the invention, which may be embodied in various forms.
It is also to be understood that the terms “a”, “an”, “the” and like are words for the sake of convenience and are not to be construed as limiting terms. Moreover, it will be understood that the illustrations are for the purpose of describing a particular exemplary embodiment of the invention and are not limited to the invention thereto.
The term "fibers" or "fiber" or "fabric" or "fabrics" are interchangeable and intend to cover single as well as plural fiber or fabric.
The unit "%" of the void volume or component means to interpret % volume of void or component by volume of the composite product.
According to one of the embodiments of the invention, there is provided a honeycomb closed cellular composite product consisting of essen¬tially multiple layers of a synthetic polyester felt impregnated with a resin system and / or multiple layers of a bi-directionally and a uni-directionally oriented synthetic glass fabric impregnated with a resin system to form a core and an encapsulated layer;
the core comprising non-spaced-apart closed cellular polygonal columnar units, particularly hexagonal columnar units stacked alongside one another to fill the void of the core; the product is having at least 50 % void vol./vol. and it is having robust impact resistance yet being low cost and light weight product.
Typically, the core comprises non-spaced-apart closed cellular hexagonal columnar units stacked alongside one another with its operative height equal to the operative height of the core. The centre of the core is made of hexagonally aligned units while the edges comprise polygonal units with suitable number of sides to pack the core. These hexagonal columnar units are stacked alongside one another as well as stacked height-wise, to form plurality of layers, such that they pack the core in its entirety.
In at least an embodiment, the centre of the core is made of hexagonally aligned units while the edges comprise polygonal units with suitable number of sides to pack the core. These polygonal units may be hexagonal units for the most part and portions thereof to form the non-spaced-apart fill in the core. These hexagonal columnar units may or may not be interconnected with each other.
Particularly, the composite product of the invention reduces environmental impact as the present invention utilizes the waste plastic/ polyester felt.
Particularly, the composite prod¬uct with robust impact resistance of the invention is used in dynamic applications including impeding impactor or projectile travelling at high speed or in aerospace, automotive or construction, etc.
Particularly, the mats, felts, fibers or fabrics of the synthetic polyester felt or the bi-directionally and uni-directionally oriented synthetic glass fabric are impregnated with at least 48 % wt./wt. with the resin system of the total weight of the product.
Particularly, the core comprises the multiple layers of the bi-directionally and uni-directionally oriented synthetic glass fabric impregnated with the resin system and / or the synthetic polyester felt impregnated with the resin system.
More particularly, the core comprises the multiple alternate layers of the bi-directionally and the uni-directionally oriented synthetic glass fabric impregnated with the resin system and the synthetic polyester felt impregnated with the resin system.
Particularly, the encapsulated layer comprises either
• multiple layers of the bi-directionally and the uni-directionally oriented synthetic glass fabric impregnated with the resin system and / or the synthetic polyester felt impregnated with the resin system;
OR
• a first and a last layer of the bi-directionally and the uni-directionally oriented synthetic glass fabric impregnated with the resin system and in-between them are multiple layers of the synthetic polyester felt impregnated with the resin system;
OR
• a first and a last layer of the synthetic polyester felt impregnated with the resin system and in-between them are multiple layers of the bi-directionally and the uni-directionally oriented synthetic glass fabric impregnated with the resin system.
OR
• a first multiple layers of the bi-directionally and the uni-directionally oriented synthetic glass fabric impregnated with the resin system to form an outer peripheral thickness of the encapsulated layer and a last multiple layers of the synthetic polyester felt impregnated with the resin system to form an inner peripheral thickness of the encapsulated layer;
OR
• a first multiple layers of the synthetic polyester felt impregnated with the resin system to form the outer peripheral thickness of the encapsulated layer and a last multiple layers of the bi-directionally and the uni- directionally oriented synthetic glass fabric impregnated with the resin system to form the inner peripheral thickness of the encapsulated layer;
OR
• multiple layers of the bi-directionally and the uni-directionally oriented synthetic glass fabric impregnated with the resin system and / or the synthetic polyester felt impregnated with the resin system having the bi- directionally and the uni-directionally oriented synthetic glass fabric impregnated with the resin system as outermost encapsulated layer;
OR
• multiple layers of the bi-directionally and the uni-directionally oriented synthetic glass fabric impregnated with the resin system and / or the synthetic polyester felt impregnated with the resin system having the synthetic polyester felt impregnated with the resin system as outermost encapsulated layer.
More particularly, the encapsulated layer comprises either
• a first multiple layers of the synthetic polyester felt impregnated with the resin system to form the outer core layer and a last multiple layers of the bi-directionally and the uni- directionally oriented synthetic glass fabric impregnated with the resin system to form the inner core layer;
OR
• a first multiple layers of the bi-directionally and the uni-directionally oriented synthetic glass fabric impregnated with the resin system to form the outer core layer and a last multiple layers of the synthetic polyester felt impregnated with the resin system to form the inner core layer;
OR
• multiple layers of the bi-directionally and the uni-directionally oriented synthetic glass fabric impregnated with the resin system and / or the synthetic polyester felt impregnated with the resin system having the synthetic polyester felt impregnated with the resin system as outermost core layer;
OR
• multiple layers of the bi-directionally and the uni-directionally oriented synthetic glass fabric impregnated with the resin system and / or the synthetic polyester felt impregnated with the resin system having the bi- directionally and the uni-directionally oriented synthetic glass fabric impregnated with the resin system as outermost core layer.
The product of the invention has characteristic features of
1. a peripheral thickness of the encapsulated layer is at least of 1.0 mm;
2. an inner vertical wall thickness of the hexagonal units of the core is at least of 1.0 mm; and
3. an inner slant wall thickness of the hexagonal units of the core is at least of 1.0 mm.
The peripheral thickness of the encapsulated layer is divided into outer peripheral thickness and inner peripheral thickness. The outer peripheral thickness and the inner peripheral thickness are of at least 0.5 mm each.
These characteristic features may be tailored or engineered regarding its thickness and the sequence in which the synthetic polyester felt and the synthetic glass fabric used therein, to control or tailor impact resistance of the product of the invention, stress, deflection, etc as per the requirement of end applications.
The bi-directionally and the uni-directionally synthetic glass fabric can be replaced by polyester, carbon, aramid, basalt and mixtures thereof.
Preferably, said synthetic glass fabric is oriented either uni-directionally or bi-directionally and is having a moisture content of 5 % or less, weight of 200 to 1000 gm/m2, 200 to 500 gm/ m2 and tensile strength of 400 to 500 MPa.
The resin system used for impregnation of the synthetic polyester felt and the bi-directionally and the uni-directionally oriented synthetic glass fabric; comprise of at least a resin; a curing system comprising curing agent and accelerator; filler; thinner; pigment or any other suitable additives.
Particularly, the resin used in the resin system is either a thermosetting resin selected from unsaturated polyester, epoxy, polyurethane, phenolic resins and mixture thereof or a thermoplastic resin selected from polyethylene, polypropylene, acrylonitrile-butadiene-styrene, polyacetal, polyamide, polyimide, saturated polyester resins and mixtures thereof.
Particularly, the curing agent used in the resin system is selected from methyl ethyl ketone peroxide, cumene hydroperoxide, t-butyl hydroperoxide, benzoyl peroxide, and / or hydrogen peroxide.
Particularly, the accelerator used in the resin system is selected from cobalt naphthenate and/or cobalt octoate.
Particularly, the filler used in the resin system is calcium carbonate.
Particularly, thinner is methanol.
Particularly, the resin systems used in the present invention are:
a) the resin system comprises epoxy resin and hardner or curing agent in the ratio of 1:1 and 3:1; and
b) the resin system comprises at least 100 pph of polyester resin, at least 1.7 pph of curing
system, at least 2 pph of filler, and at least 10 pph of thinner.
Particularly, the resin system comprises 100 pph of polyester, 1.7 pph of curing system comprising 0.2 pph of cobalt octoate and 1.5 pph of benzoyl peroxide, 2 pph of calcium carbonate and 10 pph of methanol.
The synthetic polyester felt used in the composite products of the invention may be in any form made from plastic waste or polyester waste. More particularly, it is in the form of needle punched mat having weight in the range of 400 to 1000 gm / m2. The needle punched mat of synthetic polyester felt is prepared from waste polyester felt to reduce the cost of production.
In an exemplary embodiment, the synthetic polyester felt or the polyester felt mat have weight of 400 to about 1000 GSM and have following properties namely; Mass (ASTM D 5261) 1000 GSM; Tensile Strength (Wide Width) (ASTM D 4595) 40 KN/m; Elongation (ASTM D 4595) 55%; Grab Tensile Strength (ASTM D 4632) 1850 N; Grab Tensile Elongation (ASTM D 4632) >55 %; CBR (ASTM D 6241) 4500 N; Opening Size (O90) (ASTM D 4751) 60 Microns; Thickness 4 mm; and Trap Tear (ASTM D 4533) 950 N.

DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Figure 1 illustrates a profile of a honeycomb closed cellular composite product (100), where the core (101) comprises non-spaced-apart closed cellular polygonal units (101A) stacked alongside one another to fill the void of the core (101), which is enclosed in encapsulated layer (102).
In at least an embodiment, these polygonal units (101) are units stacked alongside one another with its operative height equal to the operative height of the core (101).
In at least an embodiment, these polygonal units (101) are stacked alongside one another as well as stacked height-wise, to form a plurality of layers, such that they pack the core (101) in its entirety.
In at least an embodiment, the centre of the core is made of hexagonal units while the edges comprise polygonal units with suitable number of sides to pack the core in its entirety.
Typically, these polygonal units may be hexagonal units (101A) for the most part and portions thereof to form the non-spaced-apart fill in the core (101).
These polygonal units (101A) may or may not be interconnected with each other.
Figure 2 illustrates a cross-sectional view of the profile of the honeycomb closed cellular composite product (100), where
1. a peripheral thickness (D) of the encapsulated layer (102) is of at least 1.0 mm;
2. an inner vertical wall thickness (E) of the hexagonal units (101A) of the core (101) is of at least 1.0 mm; and
3. an inner slant wall thickness (F) of the hexagonal units (101A) of the core (101) is of at least of 1 mm.
Particularly, the peripheral thickness (D) of the encapsulated layer (102) is in the range of 1.0 mm to 100 mm.
Particularly, the inner vertical wall thickness (E) of the hexagonal units (101A) of the core (101) is in the range of 1.0 mm to 100 mm; and
Particularly, the inner slant wall thickness (F) of the hexagonal units (101A) of the core (101) is in the range of 1.0 mm to 100 mm.

Particularly, the peripheral thickness (D) of the encapsulated layer may further be divided into outer peripheral thickness (D1) of at least 0.5 mm; the inner peripheral thickness (D2) of at least 0.5 mm.
The peripheral thickness (D) of the encapsulated layer including (D1) and (D2), the inner vertical wall thickness (E) and the inner slant wall thickness (F) of the polygonal including hexagonal units (101A) of the core (101) and the preferences in which the bi-directionally and the uni-directionally oriented synthetic glass fabric impregnated with the resin system and the synthetic polyester felt impregnated with the resin system used to form the core (101) and the encapsulated layer (102) are essential parameters to produce the composite product of the invention to have robust impact resistance and deflection with reduced stress. The essential parameters may be varied to control the impact resistance, stress and deflection.
The peripheral thickness (D) of the encapsulated layer including (D1) and (D2), the inner vertical wall thickness (E) and the inner slant wall thickness (F) of the polygonal including hexagonal units (101A) may alter to any desired thickness depending upon the end applications.
Particularly, the core (101) comprises of the multiple layers of the bi-directionally and the uni-directionally oriented synthetic glass fabric impregnated with the resin system and / or the synthetic polyester felt impregnated with the resin system. More particularly, the core (101) comprises of the multiple alternate layers of the bi-directionally and the uni-directionally oriented synthetic glass fabric impregnated with the resin system and the synthetic polyester felt impregnated with the resin system.
Particularly, the encapsulated layer (102) comprises of either multiple layers of the bi-directionally and the uni-directionally oriented synthetic glass fabric impregnated with the resin system and / or the synthetic polyester felt impregnated with the resin system; OR a first and a last layer of the bi-directionally and the uni-directionally oriented synthetic glass fabric impregnated with the resin system and in-between them are multiple layers of the synthetic polyester felt impregnated with the resin system; OR a first and a last layer of the synthetic polyester felt impregnated with the resin system and in-between them are multiple layers of the bi-directionally and the uni-directionally oriented synthetic glass fabric impregnated with the resin system; OR a first multiple layers of the synthetic polyester felt impregnated with the resin system to form the outer peripheral thickness (D1) of the encapsulated layer and a last multiple layers of the bi-directionally and the uni-directionally oriented synthetic glass fabric impregnated with the resin system to form the inner peripheral thickness (D2) of the encapsulated layer; OR a first multiple layers of the bi-directionally and the uni-directionally oriented synthetic glass fabric impregnated with the resin system to form the outer peripheral thickness (D1) of the encapsulated layer and a last multiple layers of the synthetic polyester felt impregnated with the resin system to form the inner peripheral thickness (D2) of the encapsulated layer; OR multiple layers of the bi-directionally and the uni-directionally oriented synthetic glass fabric impregnated with the resin system and / or the synthetic polyester felt impregnated with the resin system having the bi-directionally and the uni-directionally oriented synthetic glass fabric impregnated with the resin system as outermost encapsulated layer; OR multiple layers of the bi-directionally and the uni-directionally oriented synthetic glass fabric impregnated with the resin system and / or the synthetic polyester felt impregnated with the resin system having the synthetic polyester felt impregnated with the resin system as outermost encapsulated layer.
Preferably, the encapsulated layer (102) comprises: the first and the last layer of the bi-directionally and the uni-directionally oriented synthetic glass fabric impregnated with the resin system and in-between them are multiple layers of the synthetic polyester felt impregnated with the resin system; OR the first multiple layers of the bi-directionally and the uni-directionally oriented synthetic glass fabric impregnated with the resin system to form the outer peripheral thickness (D1) of the encapsulated layer and the last multiple layers of the synthetic polyester felt impregnated with the resin system to form the inner peripheral thickness (D2) of the encapsulated layer; OR multiple layers of the bi-directionally and the uni-directionally oriented synthetic glass fabric impregnated with the resin system and / or the synthetic polyester felt impregnated with the resin system having the bi-directionally and the uni-directionally oriented synthetic glass fabric impregnated with the resin system as outermost encapsulated layer.
According to one of the embodiments of the invention, there is provided a pultrusion apparatus for a continuous or a batch production of the honeycomb closed cellular composite product; particularly the product having the profile as shown in figure (1).
Figure 3 illustrates the pultrusion apparatus (200) for the continuous or the batch production of the honeycomb closed cellular composite product; particularly the product having profile as shown in Figure (1).
In Figure 3, at least one roller stand (106) is used in place of conventionally used creel stand. The roller stand occupies less space as compared to creel stand.
The pultrusion apparatus (200) for the continuous or the batch production of the honeycomb closed cellular composite product of the invention comprises:
at least one roller stand (106) provided with at least two roller means (107 and 108) to feed at least one synthetic polyester felt and at least one bi-directionally and uni-directionally oriented synthetic glass fabric;
a resin bath (109) comprising a resin system for impregnation of the fibers/ felt / fabric; the resin bath (109) is in a close proximity to the roller stand (106) so as to pass the polyester felt and the synthetic glass fabric through it to impregnate the same with the resin system;
a pultrusion die (110) comprises plurality of guides (114), plurality of floating mandrels (115) and a passage (116a) available between an inner surface of the die (110) and the mandrels (115) and plurality of passages (116b) between the mandrels (115); the pultrusion die (110) provided in a close proximity to the resin bath (109) to pass the resin impregnated fibers/ felts / fabrics through the guides (116) into the passages (116 - 116a and 116b) so as to simultaneously form a core (101) and an encapsulated layer (102) while arranging the encapsulated layer (102) to enclose over the core (101) and;
at least one heating mean (111), preferably heating plates provided to encapsulate the pultrusion die (110) to fuse closed cellular hexagonal columnar units to form the core (101) and also to fuse the encapsulated layer (102) to enclose the core (101); the pultrusion die (110) being activated by heating to transfer the honeycomb closed cellular composite product to further location;
at least one external pultrusion puller (112) provided in close proximity to the pultrusion die (110) to expel the honeycomb closed cellular composite product from the die (112); and
a cutter (113) provided at the end of the apparatus to cut the honeycomb closed cellular composite product of a desired length;
the product comprises essen¬tially multiple layers of the synthetic polyester felt impregnated with the resin system and multiple layers of the bi-directionally and the uni-directionally oriented synthetic glass fabric impregnated with the resin system arranged to form the core (101) and the encapsulated layer (102);
particularly the core (101) is formed by stacking non-spaced-apart closed cellular polygonal units (101A) alongside one another to fill the void of the core (101), and the core is enclosed in the encapsulated layer (102);
the product having at least 50 % void vol./vol. and robust impact resistance at low cost and light weight.
Particularly, the product having 50 to 70 % void vol./vol.
Typically, the impregnated mats, felts, fibers or fabrics are at least 48 % wt./wt. impregnated with the resin system of the total weight of the product.
Figure 4 illustrates the exploded view of the pultrusion die (110).
The pultrusion die (110) having plurality of guides (114), plurality of floating mandrels (115), a passage (116a) available between an inner surface of the die (110) and the mandrels (115) and plurality of passages (116b) available between the mandrels (115) along their length. The floating mandrels (115) have elongated floating hexagonal shaped hollow mandrels. The guides (114) and floated mandrels (115) using the passages (116b) between the mandrels (115) along their length and the passage (116a) available between an inner surface of the die (110) and the mandrels (115) channelize to pass the felt and the synthetic fabric, both impregnated with the resin system, through the passages (116b) and the passage (116a) in a desired sequence so as to form simultaneously the core (101) and the encapsulated layer (102) respectively, and arranging the encapsulated layer (102) over the core (101) to enclose the core (101) with the encapsulated layer (102). The die (110) is encapsulated with heating plates (111) so as to maintain the die (110) at a temperature in the range of 110 to 130° C. The heating initiate curing so as to fuse polygonal columnar units, predominantly hexagonal units to form the core and also to fuse the encapsulated layer over the core.
The floating mandrel (115) has elongated floating hexagonal shaped hollow floating mandrel.
Typically, the resin bath (111) is operated at speed of 2 to 6 meter per hour to impregnate the synthetic polyester felt and the oriented synthetic fabric with the resin system.
Typically, the pultrusion die (110) is operated at speed of 2 to 6 meter per hour to process the impregnated felt and fabric with the resin system through it to obtain the honeycomb closed cellular composite product.
According to still another embodiment of the invention, there is provided a pultrusion method for production of the honeycomb closed cellular composite prod¬uct of the invention by using the pultrusion apparatus (200) of the invention as illustrated in Figure 3.
In this method, the synthetic polyester felt and the bi-directionally or the uni-directionally oriented synthetic glass fabric are provided by roller means (107, 108). These felts / fibers /fabrics are passed through the resin bath (109) comprising the resin system at speed of 2 to 6 meter per hour to impregnate them with the resin system followed by passing them at speed of 2 to 6 meter per hour through the pultrusion die (110) maintaining the temperature of 110 to 130° C by using the heating means (111). In the pultrusion die (110), the impregnated felt and oriented glass fabric with the resin system in a desired sequence are passed though the guides (114) followed through the passage (116a) available between the inner surface of the die (110) and the mandrels (115) and the passages (116b) between the mandrels (115) along the length of the die (110) to simultaneously form the encapsulated layer (102) and the core (101), particularly arranging the encapsulated layer (102) over the core (101) to enclose it. The core so obtained predominantly comprises non-spaced-apart closed cellular hexagonal columnar units (101A) stacked alongside one another to fill the void of the core (101) while the edges comprise polygonal units with suitable number of sides to pack the core. The heating allows a curing leading to fusion of the closed columnar hexagonal units to form the core (101) and fusion of the encapsulated layer (102) over the core (101). The die (110) is activated by heating using the heating means (111) to transfer a cured pultruded honeycomb closed cellular composite product to expel out by using the external pultrusion puller (112). The product of the desired length is cut with the help of cutter (113).
According to the method of the present invention, the non-spaced-apart closed cellular polygonal units (101A) stacked alongside one another to form the core (101), which is enclosed in the encapsulated layer (102). The centre of the core is made of hexagonal columnar units while the edges comprise polygonal units with suitable number of sides to pack the core. Particularly, these polygonal columnar units (101) are stacked alongside one another as well as stacked height-wise, to form a plurality of layers, such that they pack the core (101) in its entirety. These polygonal columnar units (101) may or may not be interconnected with each other. The polygonal columnar units including hexagonal units (101) obtained according to the method of the invention has the inner vertical wall thickness (E) of at least 1 mm, typically in the range of 1 mm to 100 mm and the inner slant wall thickness (F) of at least 1 mm, typically 1 to 100 mm. The peripheral thickness (D) of the encapsulated layer is of at least 1 mm, typically 1 to 100 mm. Typically, the peripheral thickness (D) of the encapsulated layer may be further divided into outer peripheral thickness (D1) of at least 0.5 mm; and the inner peripheral thickness (D2) of at least 0.5 mm.
The inner vertical wall thickness (E) and the inner slant wall thickness (F) of the core (101) and the peripheral thickness (D) including (D1) and (D2) of the encapsulated layer (102) of the honeycomb closed cellular composite product can be varied regarding thickness and the preferences in which the bi-directionally and the uni-directionally oriented synthetic glass fabric impregnated with the resin system and the synthetic polyester felt impregnated with the resin system used to form the core (101) and the encapsulated layer (102) to tailor or control the properties namely, impact resistance, deflection and stress of the product of the invention in accordance to the requirement of the end applications, where it will be used.
According to the invention, there is provided the honeycomb closed cellular composite product comprising the synthetic polyester felt.; the bi-directionally and uni-directionally oriented synthetic glass fabric; and the resin system;
where the product has the core (101) comprising non-spaced-apart closed cellular polygonal units (101A), predominantly hexagonal columnar units stacked alongside one another to fill the void of the core (101) while the edges of the core (101) comprise polygonal units with suitable number of sides to pack the core (101);
where the core (101) and the encapsulated layer (102) made up of the multiple layers of the bi-directionally and the uni-directionally oriented synthetic glass fabric impregnated with the resin system and the synthetic polyester felt impregnated with the resin system,
where the product has 50 to 80 % void vol./vol.; and
where the product has robust impact resistance in terms of reduced stress as minimum as 601 MPa and reduced deflection as minimum as 519.69 mm.
Particularly, the product has 60 to 80 % void vol. / vol..
The resistance, stress and deflection of the product is carried out at a speed of 500 to 900 m/sec in air and applying the condition of base support or edge support by using "ANSYS" software by using parameters namely, Gruneisen Coefficient of 0.84, C1 of 3230, C2 of 0.9 and impactor speed of 900 m/s. It was found that the stress was as minimum as 601 MPa and the reduced stress was as minimum as 519.69 mm thus having robust impact resistance.
The technical advancement of the present invention over the existing product including composite product protected in Patent Application No. 201621020446 is that the honeycomb closed cellular composite product of the invention has the robust impact resistance with low stress even at a speed of 900 m/sec yet being light weight and low cost product.The product as well as the method of the invention utilizes minimum raw material, eliminates the wastage of material due to spilling thus making it clean, cost effective and efficient. The present invention enable to vary the inner vertical wall thickness (E) and the inner slant wall thickness (F) of the core (101) and the peripheral thickness (D) of the encapsulated layer (102) of the honeycomb closed cellular composite product to tailor or engineer the end properties namely, impact resistance, deflection and stress of the product of the invention in accordance to the requirement of the end applications namely impeding impactor or projectile travelling at high speed or in aerospace, automotive or construction, etc, where it will be used. The present apparatus has a roller stand instead of creel stand for feeding felts / fibers / fabrics which uses less space as compared to conventional creel stand. Thus, the current method reduces manufacturing cost, reduces environmental impact and improves composite products. The composite product of the invention overcome limitation of conventionally over designed, heavy weight and costly composites products. Also, said product is with improved low ratio of weight to strength. The method of the invention eliminates use of conventional glass roving and overcomes the limitation of high pulling forces during pulling of glass roving in resin bath. The present closed cellular composite product sustains high speed impact in X-Y and Z-Y plane. The presently invented method is a continuous or batch production method. The present method reduces manufacturing cost as it uses waste plastic, reduces environmental impact and improves the impact resistance with high endurance in adverse environmental conditions.

BEST MODE OR EXAMPLES FOR WORKING OF THE INVENTION
The present invention is described in the examples given below; further these are provided only to illustrate the invention and therefore should not be construed to limit the scope of the invention.

Example 1
The honeycomb closed cellular composite product with the width of 110 mm, length of 100 mm and height of 70 mm and having 10 number of honeycomb units or cells. The total volume of the product is 7,70,000 mm3. It was made-up of bidirectional (0/90°) oriented glass fabric, synthetic polyester felt, and the polyester resin system. The polyester resin system used in the current example consisted of 100 pph of polyester, 1.7 pph of curing system comprising 0.2 pph of cobalt octoate and 1.5 pph of benzoyl peroxide, 2 pph of calcium carbonate and 10 pph of methanol.
The bidirectional (0/90°) oriented glass fabric has weight of 200 to 1000 gm/m2 and tensile strength of 400 to 500 MPa.
The polyester felt in the form of needle punched mat is prepared from polyester waste. This mat has mass of 1000 GSM (ASTM D 5261); Tensile Strength of 40 KN/m (ASTM D 4595); Elongation of 55% (ASTM D 4595); Grab Tensile Strength of 1850 N (ASTM D 4632); Grab Tensile Elongation of >55 % (ASTM D 4632); CBR of 4500 N (ASTM D 6241); Opening Size (O90) of 60 Microns (ASTM D 4751); Thickness of 4 mm; and Trap Tear of 950 N (ASTM D 4533).
The sequence of the core comprises of the multiple alternate layers of the bi-directionally (0/90°) oriented synthetic glass fabric impregnated with the polyester resin system and the synthetic polyester felt impregnated with the polyester resin system.
The sequence of the encapsulated layer comprise the first and the last layer of the bi-directionally (0/90°) oriented synthetic glass fabric impregnated with the polyester resin system, and in-between, multiple layers of the synthetic polyester felt impregnated with the polyester resin system.
The polyester felts and the bi-directionally (0/90°) oriented glass fabrics of 200 gm /m2 were provided by roller means (107 and 108). These felts / fabrics were impregnated by passing them at speed 4 meter per hour through the resin bath (109) comprising the polyester resin system. The impregnated fabrics and felts were passed through a floated pultrusion mandrel (110) at speed 4 meter per hour and at temperature 110° C using heating means (111) to obtain a cured pultruded honeycomb closed cellular composite product. The cured product was expelled from the mandrel (110) with the help of an external pultrusion puller (112) and cut at the length of 100 mm with the help of cutter (113).
The product has a peripheral thickness (D) of 5 mm; the inner vertical wall thickness (E) of 5 mm; and the inner slant wall thickness (F) of 2.5 mm.
The void volume of the product is 64.61 % by vol./vol.
The product was tested for equivalent stress and total deformation by "ANSYS" software by using parameters namely, Gruneisen Coefficient of 0.84, C1 of 3230, C2 of 0.9 and impactor speed of 900 m/s by applying "base support" condition. The product was also tested by applying "support by the edges" condition. The results are incorporated in the table 1.

Example 2
The honeycomb closed cellular composite product with the width of 116 mm, length of 100 mm and height of 76 mm and having 10 number of honeycomb units. The total volume of the product is 8,81,600 mm3. It was made-up of the bidirectional (0/90°) oriented glass fabric, the synthetic polyester felt, and the polyester resin system.
The polyester resin system used in the current example consisted of 100 pph of polyester, 1.7 pph of curing system comprising 0.2 pph of cobalt octoate and 1.5 pph of benzoyl peroxide, 2 pph of calcium carbonate and 10 pph of methanol.
The bidirectional (0/90°) oriented glass fabric has weight of 200 to 1000 gm/m2 and tensile strength of 400 to 500 MPa.
The polyester felt in the form of needle punched mat is prepared from polyester waste. The mat has mass of 1000 GSM (ASTM D 5261); Tensile Strength of 40 KN/m (ASTM D 4595); Elongation of 55% (ASTM D 4595); Grab Tensile Strength of 1850 N (ASTM D 4632); Grab Tensile Elongation of >55 % (ASTM D 4632); CBR of 4500 N (ASTM D 6241); Opening Size (O90) of 60 Microns (ASTM D 4751); Thickness of 4 mm; and Trap Tear of 950 N (ASTM D 4533).
The sequence of the core comprises of the multiple alternate layers of the bi-directionally (0/90°) oriented synthetic glass fabric impregnated with the polyester resin system and the synthetic polyester felt impregnated with the polyester resin system.
The sequence of the encapsulated layer comprise the first and the last layer of the bi-directionally (0/90°) oriented synthetic glass fabric impregnated with the polyester resin system, and in-between, multiple layers of the synthetic polyester felt impregnated with the polyester resin system.
The product was made by following same method as described in Example 1.
The product has a peripheral thickness (D) of 8 mm; the inner vertical wall thickness (E) of 5 mm; and the inner slant wall thickness (F) of 2.5 mm.
The void volume of the product is 56.44 % by vol./vol.
The product was tested for equivalent stress and total deformation by "ANSYS" software by using parameters namely, Gruneisen Coefficient of 0.84, C1 of 3230, C2 of 0.9 and impactor speed of 900 m/s by applying base support condition. The results are incorporated in the table 1.

Example 3
The honeycomb closed cellular composite product with the width of 110 mm, length of 100 mm and height of 70 mm and having 10 number of honeycomb units. The total volume of the product is 7,70,000 mm3. It was made-up of bidirectional (0/90°) oriented glass fabric, synthetic polyester felt, and the polyester resin system.
The polyester resin system used in the current example consisted of 100 pph of polyester, 1.7 pph of curing system comprising 0.2 pph of cobalt octoate and 1.5 pph of benzoyl peroxide, 2 pph of calcium carbonate and 10 pph of methanol.
The bidirectional (0/90°) oriented glass fabric has weight of 200 to 1000 gm/m2 and tensile strength of 400 to 500 MPa.
The polyester felt in the form of needle punched mat is prepared from polyester waste. The mat has mass of 1000 GSM (ASTM D 5261); Tensile Strength of 40 KN/m (ASTM D 4595); Elongation of 55% (ASTM D 4595); Grab Tensile Strength of 1850 N (ASTM D 4632); Grab Tensile Elongation of >55 % (ASTM D 4632); CBR of 4500 N (ASTM D 6241); Opening Size (O90) of 60 Microns (ASTM D 4751); Thickness of 4 mm; and Trap Tear of 950 N (ASTM D 4533).
The sequence of the core comprises of the multiple alternate layers of the bi-directionally (0/90°) oriented synthetic glass fabric impregnated with the polyester resin system and the synthetic polyester felt impregnated with the polyester resin system.
The sequence of the encapsulated layer comprise the first and the last layer of the bi-directionally (0/90°) oriented synthetic glass fabric impregnated with the polyester resin system, and in-between, multiple layers of the synthetic polyester felt impregnated with the polyester resin system.
The product was made by following same method as described in Example 1.
The product has a peripheral thickness (D) of 5 mm; the inner vertical wall thickness (E) of 8 mm; and the inner slant wall thickness (F) of 4 mm.
The void volume of the product is 57.36 % by vol./vol.
The product was tested for equivalent stress and total deformation by "ANSYS" software by using parameters namely, Gruneisen Coefficient of 0.84, C1 of 3230, C2 of 0.9 and impactor speed of 900 m/s by applying base support condition. The results are incorporated in the table 1.

Example 4
The honeycomb closed cellular composite product with the width of 110 mm, length of 100 mm and height of 70 mm and having 27 number of honeycomb units. The total volume of the product is 7,70,000 mm3. It was made-up of bidirectional (0/90°) oriented glass fabric, synthetic polyester felt, and the polyester resin system.
The polyester resin system used in the current example consisted of 100 pph of polyester, 1.7 pph of curing system comprising 0.2 pph of cobalt octoate and 1.5 pph of benzoyl peroxide, 2 pph of calcium carbonate and 10 pph of methanol.
The bidirectional (0/90°) oriented glass fabric has weight of 200 to 1000 gm/m2 and tensile strength of 400 to 500 MPa.
The polyester felt in the form of needle punched mat is prepared from polyester waste. The mat has mass of 1000 GSM (ASTM D 5261); Tensile Strength of 40 KN/m (ASTM D 4595); Elongation of 55% (ASTM D 4595); Grab Tensile Strength of 1850 N (ASTM D 4632); Grab Tensile Elongation of >55 % (ASTM D 4632); CBR of 4500 N (ASTM D 6241); Opening Size (O90) of 60 Microns (ASTM D 4751); Thickness of 4 mm; and Trap Tear of 950 N (ASTM D 4533).
The sequence of the core comprises of the multiple alternate layers of the bi-directionally (0/90°) oriented synthetic glass fabric impregnated with the polyester resin system and the synthetic polyester felt impregnated with the polyester resin system.
The sequence of the encapsulated layer comprise the first and the last layer of the bi-directionally (0/90°) oriented synthetic glass fabric impregnated with the polyester resin system, and in-between, multiple layers of the synthetic polyester felt impregnated with the polyester resin system.
The product was made by following same method as described in Example 1.
The product has a peripheral thickness (D) of 5 mm; the inner vertical wall thickness (E) of 5 mm; and the inner slant wall thickness (F) of 2.5 mm.
The void volume of the product is 52.76 % by vol./vol.
The product was tested for equivalent stress and total deformation by "ANSYS" software by using parameters namely, Gruneisen Coefficient of 0.84, C1 of 3230, C2 of 0.9 and impactor speed of 900 m/s by applying base support condition. The results are incorporated in the table 1.

Example 5
The honeycomb closed cellular composite product with the width of 110 mm, length of 100 mm and height of 70 mm and having 7 number of honeycomb units. The total volume of the product is 7,70,000 mm3. It was made-up of bidirectional (0/90°) oriented glass fabric, synthetic polyester felt, and the polyester resin system.
The polyester resin system used in the current example consisted of 100 pph of polyester, 1.7 pph of curing system comprising 0.2 pph of cobalt octoate and 1.5 pph of benzoyl peroxide, 2 pph of calcium carbonate and 10 pph of methanol.
The bidirectional (0/90°) oriented glass fabric has weight of 200 to 1000 gm/m2 and tensile strength of 400 to 500 MPa.
The polyester felt in the form of needle punched mat is prepared from polyester waste. The mat has mass of 1000 GSM (ASTM D 5261); Tensile Strength of 40 KN/m (ASTM D 4595); Elongation of 55% (ASTM D 4595); Grab Tensile Strength of 1850 N (ASTM D 4632); Grab Tensile Elongation of >55 % (ASTM D 4632); CBR of 4500 N (ASTM D 6241); Opening Size (O90) of 60 Microns (ASTM D 4751); Thickness of 4 mm; and Trap Tear of 950 N (ASTM D 4533).
The sequence of the core comprises of the multiple alternate layers of the bi-directionally (0/90°) oriented synthetic glass fabric impregnated with the polyester resin system and the synthetic polyester felt impregnated with the polyester resin system.
The sequence of the encapsulated layer comprise the first and the last layer of the bi-directionally (0/90°) oriented synthetic glass fabric impregnated with the polyester resin system, and in-between, multiple layers of the synthetic polyester felt impregnated with the polyester resin system.
The product was made by following same method as described in Example 1.
The product has a peripheral thickness (D) of 5 mm; the inner vertical wall thickness (E) of 5 mm; and the inner slant wall thickness (F) of 2.5 mm.
The void volume of the product is 66.73 % by vol./vol.
The product was tested for equivalent stress and total deformation by "ANSYS" software by using parameters namely, Gruneisen Coefficient of 0.84, C1 of 3230, C2 of 0.9 and impactor speed of 900 m/s by applying base support condition. The results are incorporated in the table 1.

Example 6
The honeycomb closed cellular composite product with the width of 110 mm, length of 100 mm and height of 70 mm and having 10 number of honeycomb units. The total volume of the product is 7,70,000 mm3. It was made-up of bidirectional (0/90°) oriented glass fabric, synthetic polyester felt, and the polyester resin system.
The polyester resin system used in the current example consisted of 100 pph of polyester, 1.7 pph of curing system comprising 0.2 pph of cobalt octoate and 1.5 pph of benzoyl peroxide, 2 pph of calcium carbonate and 10 pph of methanol.
The bidirectional (0/90°) oriented glass fabric has weight of 200 to 1000 gm/m2 and tensile strength of 400 to 500 MPa.
The polyester felt in the form of needle punched mat is prepared from polyester waste. The mat has mass of 1000 GSM (ASTM D 5261); Tensile Strength of 40 KN/m (ASTM D 4595); Elongation of 55% (ASTM D 4595); Grab Tensile Strength of 1850 N (ASTM D 4632); Grab Tensile Elongation of >55 % (ASTM D 4632); CBR of 4500 N (ASTM D 6241); Opening Size (O90) of 60 Microns (ASTM D 4751); Thickness of 4 mm; and Trap Tear of 950 N (ASTM D 4533).
The sequence of the core comprises of the multiple alternate layers of the bi-directionally (0/90°) oriented synthetic glass fabric impregnated with the polyester resin system and the synthetic polyester felt impregnated with the polyester resin system.
The sequence of the encapsulated layer comprise the first multiple layer of the bi-directionally (0/90°) oriented synthetic glass fabric impregnated with the polyester resin system to form peripheral inner thickness of the encapsulated layer followed by last multiple layers of the synthetic polyester felt impregnated with the polyester resin system to form peripheral outer thickness of the encapsulated layer.
The product was made by following same method as described in Example 1.
The product has a peripheral outer thickness (D1) of the encapsulated layer (102) of 2.5 mm made from the polyester felt impregnated with the resin system and the peripheral inner thickness (D2) of the encapsulated layer (102) of 2.5 mm made from the unidirectional oriented synthetic glass fabric impregnated with the resin system; the inner vertical wall thickness (E) of 5 mm; and the inner slant wall thickness (F) of 2.5 mm.
The void volume of the product is 64.61 % by vol./vol.
The product was tested for equivalent stress and total deformation by "ANSYS" software by using parameters namely, Gruneisen Coefficient of 0.84, C1 of 3230, C2 of 0.9 and impactor speed of 900 m/s by applying base support condition. The results are incorporated in the table 1.

Example 7
The honeycomb closed cellular composite product with the width of 110 mm, length of 100 mm and height of 70 mm and having 10 numbers of honeycomb units. The total volume of the product is 7,70,000 mm3. It was made-up of bidirectional (0/90°) oriented glass fabric, synthetic polyester felt, and the polyester resin system.
The polyester resin system used in the current example consisted of 100 pph of polyester, 1.7 pph of curing system comprising 0.2 pph of cobalt octoate and 1.5 pph of benzoyl peroxide, 2 pph of calcium carbonate and 10 pph of methanol.
The bidirectional (0/90°) oriented glass fabric has weight of 200 to 1000 gm/m2 and tensile strength of 400 to 500 MPa.
The polyester felt in the form of needle punched mat is prepared from polyester waste. The mat has mass of 1000 GSM (ASTM D 5261); Tensile Strength of 40 KN/m (ASTM D 4595); Elongation of 55% (ASTM D 4595); Grab Tensile Strength of 1850 N (ASTM D 4632); Grab Tensile Elongation of >55 % (ASTM D 4632); CBR of 4500 N (ASTM D 6241); Opening Size (O90) of 60 Microns (ASTM D 4751); Thickness of 4 mm; and Trap Tear of 950 N (ASTM D 4533).
The sequence of the core comprises of the multiple alternate layers of the bi-directionally (0/90°) oriented synthetic glass fabric impregnated with the polyester resin system and the synthetic polyester felt impregnated with the polyester resin system.
The sequence of the encapsulated layer comprise the first multiple layer of the synthetic polyester felt impregnated with the polyester resin system to form peripheral inner thickness of the encapsulated layer followed by last multiple layers of the bi-directionally (0/90°) oriented synthetic glass fabric impregnated with the polyester resin system to form peripheral outer thickness of the encapsulated layer.
The product was made by following same method as described in Example 1.
The product has a peripheral outer thickness (D1) of the encapsulated layer of 2.5 mm made from the unidirectional oriented synthetic glass fabric impregnated with the resin system; the peripheral inner thickness (D2) of the encapsulated layer of 2.5 mm made from the polyester felt impregnated with the resin system; the inner vertical wall thickness (E) of 5 mm; and the inner slant wall thickness (F) of 2.5 mm.
The void volume of the product is 70 % by vol./vol.
The product was tested for equivalent stress and total deformation by "ANSYS" software by using parameters namely, Gruneisen Coefficient of 0.84, C1 of 3230, C2 of 0.9 and impactor speed of 900 m/s by applying base support condition. The results are incorporated in the table 1.

Example 8 (Comparative Example)
The conventional honeycomb closed cellular steel product with the width of 110 mm, length of 100 mm and height of 70 mm and having 10 number of honeycombs units. The product has a peripheral thickness (D) of 5 mm; the inner vertical wall thickness (E) of 5 mm; and the inner slant wall thickness (F) of 2.5 mm. The void volume of the product is 64.61% by vol./vol. This product is used for the comparative study.
The product was tested for equivalent stress and total deformation by "ANSYS" software by using parameters namely, Gruneisen Coefficient of 0.84, C1 of 3230, C2 of 0.9 and impactor speed of 900 m/s by applying base support condition. The results are incorporated in the table 1.

Example 9 (Comparative Example)
The honeycomb closed cellular composite product with the width of 110 mm, length of 100 mm and height of 70 mm and having 10 number of honeycomb units. The total volume of the product is 7,70,000 mm3. It was made-up of bidirectional (0/90°) oriented glass fabric, synthetic polyester felt, and the polyester resin system.
The polyester resin system used in the current example consisted of 100 pph of polyester, 1.7 pph of curing system comprising 0.2 pph of cobalt octoate and 1.5 pph of benzoyl peroxide, 2 pph of calcium carbonate and 10 pph of methanol.
The bidirectional (0/90°) oriented glass fabric has weight of 200 to 1000 gm/m2 and tensile strength of 400 to 500 MPa.
The polyester felt in the form of needle punched mat is prepared from polyester waste. The mat has mass of 1000 GSM (ASTM D 5261); Tensile Strength of 40 KN/m (ASTM D 4595); Elongation of 55% (ASTM D 4595); Grab Tensile Strength of 1850 N (ASTM D 4632); Grab Tensile Elongation of >55 % (ASTM D 4632); CBR of 4500 N (ASTM D 6241); Opening Size (O90) of 60 Microns (ASTM D 4751); Thickness of 4 mm; and Trap Tear of 950 N (ASTM D 4533). The sequence of the core comprises of the multiple alternate layers of the bi-directionally (0/90°) oriented synthetic glass fabric impregnated with the polyester resin system and the synthetic polyester felt impregnated with the polyester resin system.
The sequence of the encapsulated layer comprise the first and the last layer of the bi-directionally (0/90°) oriented synthetic glass fabric impregnated with the polyester resin system, and in-between, multiple layers of the synthetic polyester felt impregnated with the polyester resin system.
The product was made by following same method as described in Example 1. Neoprene rubber was poured in the closed cellular hexagonal columnar units of the product and allowed to cure to obtain honeycomb closed cellular composite product.
The product has a peripheral thickness (D) of 5 mm; the inner vertical wall thickness (E) of 5 mm; and the inner slant wall thickness (F) of 2.5 mm.
The void volume of the product is 0 % by vol./vol.
The product was tested for equivalent stress and total deformation by "ANSYS" software by using parameters namely, Gruneisen Coefficient of 0.84, C1 of 3230, C2 of 0.9 and impactor speed of 900 m/s by applying base support condition. The results are incorporated in the table 1.

Table 1
Example No. Equivalent Stress Deformation Set up Stress Deformation
1
Base support condition 601.68 Mpa 519.69 mm
1
support by the edges condition 656.88 MPa 519.69 mm
2
Base support condition 691.85 MPa 551.37 mm
3
Base support condition 902.65 MPa 587.24 mm
4
Base support condition 728.32 MPa 520.35 mm
5
Base support condition 688.34 MPa 522.28 mm
6
Base support condition 712.74 MPa 530.9 mm
7
Base support condition 633.34 MPa 466.52 mm
8
Base support condition 726.37 MPa 653.46 mm
9
Base support condition 706.78 MPa 566.99 mm

The composite pultruded products obtained according to examples 1 to 7 leads to significant reduction in weight as compared to that of the conventional honeycomb closed cellular steel product as well as the composite product claimed in Patent Application No. 201621020446, thereby leading to a signifi¬cant cost reduction.
The composite product of the example 1 has a most reduced stress in the range of 601 to 657 MPa and deformation of 519.69 mm.
The composite product according to example 2 is having increased peripheral thickness of the encapsulated layer (102) by keeping number of honeycombs, inner vertical wall thickness and inner slant wall thickness same as that of example 1 and has a stress of 691.85 MPa and deformation of 551.37 mm.
The composite product according to example 3 is having increased inner vertical wall thickness and increased inner slant wall thickness of the core (101) by keeping number of honeycombs and peripheral thickness same as that of example 1 and has a stress of 902.65 MPa and deformation of 587.24 mm.
The composite product according to example 4 is having increased number of honey comb i.e. 27 by keeping peripheral thickness, inner vertical wall thickness and inner slant wall thickness same as that of example 1 and has a stress of 728.32 MPa and deformation of 520.35 mm.
The composite product according to example 5 is having decreased number of honey comb i.e. 7 by keeping peripheral thickness, inner vertical wall thickness and inner slant wall thickness same as that of example 1 and has a stress of 688.34 MPa and deformation of 522.28 mm.
The composite product according to example 6 is having peripheral outer thickness (D1) of the encapsulated layer (102) of 2.5 mm made from the unidirectional oriented synthetic glass fabric impregnated with the resin system and the peripheral inner thickness (D2) of the encapsulated layer (102) of 2.5 mm made from the polyester felt impregnated with the resin system by keeping number of honeycombs, inner vertical wall thickness and inner slant wall thickness same as that of example 1 and has a stress of 712.74 MPa and deformation of 530.9 mm.
The composite product according to example 7 is having peripheral outer thickness (D1) of the encapsulated layer (102) of 2.5 mm made from the polyester felt impregnated with the resin system and the peripheral inner thickness (D2) of the encapsulated layer (102) of 2.5 mm made from the unidirectional oriented synthetic glass fabric impregnated with the resin system by keeping number of honeycombs, inner vertical wall thickness and inner slant wall thickness same as that of example 1 has a stress of 633.34 MPa and deformation of 466.52 mm.
The steel product according to example 8 is having number of honeycombs, peripheral thickness, inner vertical wall thickness and inner slant wall thickness same as that of example 1 and has a stress of 726.37 MPa and deformation of 653.46 mm.
The composite product according to example 9 is having number of honeycombs, peripheral thickness, inner vertical wall thickness and inner slant wall thickness same as that of example 1 except the cells are filled with rubber and has a stress of 706.78 MPa and deformation of 566.99 mm.
The products with examples 1, 2, 5 and 7 showed superior or robust impact resistance and shock dissipation and least stress and deformation. The composite product of the present invention where;
the encapsulated layer comprises the first and the last layer of the bi-directionally (0/90°) oriented synthetic glass fabric impregnated with the polyester resin system, and in-between, multiple layers of the synthetic polyester felt impregnated with the polyester resin system;
and
the peripheral outer thickness (D1) of the encapsulated layer of 2.5 mm made from the unidirectional oriented synthetic glass fabric impregnated with the resin system and the peripheral inner thickness (D2) of the encapsulated layer of 2.5 mm made from the polyester felt impregnated with the resin system;
demonstrated highest improvement in stress and deformation as well. These products have better improvement in shock dissipation.

The current invention has following advantages:
1. Low cost;
2. Easy processing system;
3. High toughening strength i.e. High Impact resistance;
4. Highly resilient;
5. Light weight ;
6. Utilizes 80% waste materials and hence eco-friendly;
7. Continuous production;
8. Less energy consumption and
9. High endurance when exposed to adverse environmental conditions.

The results illustrated the table 1 unequivocally establish the superior traits of composite product prepared in accordance with the present invention as compared to conventional product.
,CLAIMS:We claim:

1. A honeycomb closed cellular composite product consisting of essen¬tially multiple layers of a synthetic polyester felt impregnated with a resin system and / or multiple layers of a bi-directionally and a uni-directionally oriented synthetic glass fabric impregnated with a resin system to form a core and an encapsulated layer;
wherein the core comprising non-spaced-apart closed cellular polygonal columnar units stacked alongside one another with its operative height equal to the operative height of the core, stacked alongside one another to fill the void of the core;
the product having at least 50 % void vol. /vol. and having robust impact resistance yet being low cost and light weight product.
2. The product as claimed in claim 1, wherein the core comprising non-spaced-apart closed cellular hexagonal columnar units stacked alongside one another with its operative height equal to the operative height of the core.
3. The product as claimed in claim 2, wherein a centre of the core is made of hexagonally aligned units while edges comprise polygonal units with suitable number of sides to pack the core.
4. The product as claimed in claim 3, wherein the polygonal columnar units may not be interconnected with each other.
5. The product as claimed in claim 1, wherein the product has 50 to 70 % void vol./vol.
6. The product as claimed in claim 5, wherein the impregnated mats, felts, fibers or fabrics are at least 48 % wt./wt. impregnated with the resin system of the total weight of the product.
7. The product as claimed in claim 1, wherein the product has the characteristic features of
a. a peripheral thickness of the encapsulated layer is at least of 1 mm;
b. an inner vertical wall thickness of the hexagonal units of the core is at least of 1 mm; and
c. an inner slant wall thickness of the hexagonal units of the core is at least of 1 mm.
8. The product as claimed in claim 7, wherein the peripheral thickness of the encapsulated layer consists of outer peripheral thickness and inner peripheral thickness.
9. The product as claimed in claim 1, wherein the synthetic glass fabric is oriented either uni-directionally or bi-directionally having a moisture content of 5 % or less, weight of 200 to 1000 gm/m2, 200 to 500 gm/ m2 and tensile strength of 400 to 500 MPa.
10. The product as claimed in claim 1, wherein the synthetic polyester felt is having weight in the range of 400 to 1000 gm / m2 and it is prepared from plastic or polyester waste.
11. The product as claimed in claim 1, wherein the resin system comprises at least a resin, a curing system comprising curing agent and accelerator, filler, thinner, pigment or any other suitable additives.
12. A pultrusion apparatus for a continuous or a batch production of the honeycomb closed cellular composite product as claimed in claim 1; said apparatus comprises:
i. at least one roller stand (106) provided with at least two roller means (107 and 108) to feed at least one synthetic polyester felt and at least one bi-directionally and uni-directionally oriented synthetic glass fabric;
ii. a resin bath (109) comprising a resin system for impregnation of the fibers/ felt / fabric; the resin bath (109) placed in a close proximity to the roller stand (106) so as to pass the polyester felt and the synthetic glass fabric through it to impregnate the same with the resin system;
iii. a pultrusion die (110) comprises guides (114), plurality of floating mandrels (115) and passage (116a) available between an inner surface of the die (110) and the mandrels (115) and passages (116b) between the mandrels (115); the pultrusion die (110) provided in a close proximity to the resin bath (109) to pass the resin impregnated fibers/ felts / fabrics through the guides (116) into the passages (116a and 116b) so as to simultaneously form a core (101) and an encapsulated layer (102) while arranging the encapsulated layer (102) to enclose over the core (101);
iv. at least one heating mean (111), preferably heating plates provided to encapsulate the pultrusion die (110) to fuse closed cellular hexagonal columnar units to form the core (101) and also to fuse the encapsulated layer (102) to enclose the core (101); the pultrusion die (110) being activated by heating to transfer the honeycomb closed cellular composite product to further location;
v. at least one external pultrusion puller (112) provided in close proximity to the pultrusion die (110) to expel the honeycomb closed cellular composite product from the die (112); and
vi. a cutter (113) provided at the end of the apparatus to cut the honeycomb closed cellular composite product of a desired length.
13. The apparatus as claimed in claim 12, wherein the pultrusion die (110) having plurality of guides (114), plurality of floating mandrels (115), a passage (116a) available between an inner surface of the die (110) and the mandrels (115) and plurality of passages (116b) available between the mandrels (115) along their length.
14. The apparatus as claimed in claim 12, wherein the die (110) is maintained at a temperature in the range of 110 to 130° C by using the heating plates (111).
15. A pultrusion method for production of the honeycomb closed cellular composite prod-uct as claimed in claim 1, by using the pultrusion apparatus (200) as claimed in claim 12, wherein the said method comprises:
A. providing synthetic polyester felt and bi-directionally or uni-directionally oriented synthetic glass fabric by roller means (107, 108);
B. passing the felt / fiber /fabric through the resin bath (109) comprising the resin system at speed of 2 to 6 meter per hour to impregnate them with the resin system;
C. passing the impregnated felt / fiber /fabric through the pultrusion die (110) at speed of 2 to 6 meter per hour maintaining the temperature of 110 to 130° C by using the heating means (111) to obtain a cured pultruded honeycomb closed cellular composite product;
D. expelling the cured pultruded honeycomb closed cellular composite product by using the external pultrusion puller (112); and
E. cutting the product of the desired length with the help of cutter (113).
16. The method as claimed in claim 15; wherein the impregnated felt and oriented glass fabric with the resin system is passed in a desired sequence though the plurality of guides (114) of the pultrusion die (110) followed by passing through the passage (116a) available between an inner surface of the die (110) and the mandrels (115) and the plurality of passages (116b) between the mandrels (115) along the length of the die (110) to simultaneously form the encapsulated layer (102) and the core (101), particularly arranging the encapsulated layer (102) over the core (101) to enclose it; the core comprises non-spaced-apart closed cellular hexagonal columnar units (101A) stacked alongside one another to fill the void of the core (101) while the edges comprise polygonal units with suitable number of sided to pack the core.

Dated this 1st Day of August 2019

(Dr Shilpa H Gharve)
Agent for the Applicant