DESC:TECHNICAL FIELD OF THE INVENTION:
The present invention relates to sealants and more particularly, to phthalate free sealant composition.
BACKGROUND OF THE INVENTION:
Sealants are the sealing compounds used for sealing assemblies and joints, prevent ingress of dust, dirt, and moisture & water. Sealants include higher-strength adhesives, low-strength putties, caulks and the like. However, putties and caulks are used only for space and void filling. Sealants, do not have great strength however possess properties such as substrate sealing at the glue line, keeping the component moisture, dirt, dust or water free, provide thermal and acoustical insulation, may serve as a fire barrier, may possess electrical properties and may be used for smoothing or filleting.
When sealants are used between substrates having different thermal coefficients of expansion or differing elongation under stress, they require adequate flexibility and elongation. The sealers are usually used in a paste form that facilitates easy filling of gaps and crevices. The sealants maintain sealing properties for the expected lifetime, service conditions and environments. The sealant material formulations generally contain resins, fillers, a plasticizer, an adhesion promoter and an elastomer. The sealant performs the functions by way of correct formulation to achieve specific application and performance properties.
The simplicity and reliability offered by organic elastomers usually make the sealants a better choice over welding or other fastening mechanisms. The current state of art includes seam sealer. The seam sealers are generally used for sealing the sheet metal overlap joints that occur in the assembly of a vehicle. This sealing helps us against air and water leaks. Such overlaps are typically decorative rather than structurally supportive. Accordingly, they are usually only spot welded and this process results in a closure that is not air or water tight. Seam sealants are sprayed or extruded over the joined edges of the overlaps, with the help of nozzles manually or by using robot thereby forming thermoset seal by passing through hot air oven.
The current sealers formulations contain resin, fillers, additive, adhesion promoter, absorbent, plasticizer, stabilizer chemicals. One of the constituent used in form of additive in majority of the application is pthalate. However phthalate poses major hazard to human health. The phthalates act as endocrine disruptors, they interfere with the chemicals that shape human development. The use of phthalates may affect the human bodies in significant ways. Studies have shown that the phthalate exposure declines male fertility thereby affecting testicular development, sperm quality etc. In women, the phthalate exposure may lead to development of breast cancer. The phthalate exposure to pregnant women may affect genital development of male children. And across genders, phthalates show a correlation with obesity and insulin resistance.
The survey states that the countries like California, Vermont, Washington, San Francisco and European Union have banned certain types of phthalates from children's products, and the FDA as well has recommended keeping them out of pharmaceuticals due to potential health risks. Phthalate free sealants have been introduced long back that includes the incorporation of bio-based plasticizer instead of conventional one. However, such bio based products are not accessible everywhere in adequate amount. Also, some of the bio based resources may not be incorporated directly due to the miscibility property of these plasticizers with PVC. They need to be chemically treated for better miscibility which further increases raw material processing cost.
Accordingly, there is a need of the seam sealer that eliminates conventional plasticizer and use phthalate free material with appropriate components to plasticize the base resin.

SUMMARY OF THE INVENTION
The present invention provides a seam sealer composition that eliminates conventional plasticizer and use phthalate free material to plasticize the base resin. The seam sealer composition comprises a predefined amount of poly vinyl chloride (PVC) resin mixture containing a predefined amount of PVC copolymer resin, a predefined amount of PVC homopolymer resin and a predefined amount of blend resin. The seam sealer composition comprises a predefined amount of filler mixture. The filler mixture includes a predefined amount of coated filler and a predefined amount of non-coated filler. The seam sealer composition comprises a predefined amount of adhesion promoter material. The seam sealer composition includes a predefined amount of absorbent material. The seam sealer composition includes a predefined amount of stabilizer material. The seam sealer composition comprises a predefined amount of plasticizer mixture having a first plasticizer mixture and a second plasticizer. The first plasticizer mixture includes a primary phthalate free plasticizer and a secondary phthalate free plasticizer mixed in a predefined proportion.
DETAILED DESCRIPTION OF THE INVENTION
Although specific terms are used in the following description for sake of clarity, these terms are intended to refer only to particular structure of the invention selected for illustration in the drawings, and are not intended to define or limit the scope of the invention.
References in the specification to “one embodiment” or “an embodiment” mean that a particular feature, structure, characteristic, or function described in connection with the embodiment is included in at least one embodiment of the invention. The appearances of the phrase “in one embodiment” in various places in the specification are not necessarily all referring to the same embodiment.
In general aspect, the present invention relates to a formulation of seam sealer that eliminates conventional plasticizer and use phthalate free material to plasticize the base resin. The formulation includes Tributyl citrate (TBC) as primary plasticizer and Chlorinated paraffin wax (CPW) as secondary plasticizer and other predefined components.
In the context of the present invention, the seam sealer composition comprising:
a predefined amount of poly vinyl chloride (PVC) resin mixture;
a predefined amount of filler mixture;
a predefined amount of adhesion promoter material;
a predefined amount of absorbent material;
a predefined amount of stabilizer material; and
a predefined amount of plasticizer mixture.
In a preferred embodiment, the PVC resin mixture includes a predefined amount of PVC copolymer resin, a predefined amount of PVC homopolymer resin and a predefined amount of blend resin. The PVC copolymer resin is in a range from about 5 Wt. % to 10 Wt. %, based on total weight of said seam sealer composition. The PVC homopolymer resin is in a range from about 5 Wt. % to 10 Wt. %, based on total weight of said seam sealer composition. The blend resin is in a range from about 3Wt. % to 5 Wt. %, based on total weight of said seam sealer composition. In the context of the present invention, the PVC resin is Chloro ethylene that acts as a resin system which imparts the physical properties to the seam sealer composition such as strength, rigidity and the like.
The filler mixture includes a predefined amount of coated filler and a predefined amount of non-coated filler. The coated filler is in a range of 10 Wt. % to 15Wt. % or optionally in range of 10 Wt. % to 25Wt. %, based on total weight of said seam sealer composition. The non-coated filler is in a range of 20 Wt. % to 30 Wt. %, based on total weight of said seam sealer composition. In the context of the present invention, the filler used is Carbonic acid calcium salt that helps to improve the workability, sagging resistance and extrusion properties required in application.
The adhesion promoter material is in a range of 3 Wt. % to 6 Wt. %, based on total weight of said seam sealer composition. In the context of the present invention, the adhesion promoter material is 2-[[4-[2-[4-(Oxiran-2-ylmethoxy) phenyl] propan-2-yl] phenoxy] methyl] oxirane that helps to improve the adhesion with CED coated surface.
The absorbent material is in a range of 1 Wt. % to 3 Wt. %, based on total weight of said seam sealer composition. In the context of the present invention, the absorbent material is Calcium Oxide that helps the seam sealer composition to absorb moisture content.
The stabilizer material is in a range of 1 Wt. % to 2 Wt. %, based on total weight of said seam sealer composition. In the context of the present invention, the stabilizer material is Oxozinc that acts as a heat stabilizer to help improve the thermal stability of the seam sealer composition.
The plasticizer mixture includes a first plasticizer mixture and a second plasticizer. The first plasticizer mixture includes a primary phthalate free plasticizer and a secondary phthalate free plasticizer that are present in a predefined proportion of 8:2. Preferably, the primary plasticizer is Tributyl 2-hydroxypropane-1,2,3-tricarboxylate and the secondary plasticizer is 8-bromo-9-chlorododec-1-ene. The first plasticizer mixture is present in a range of 20 Wt. % to 25 Wt. %, based on total weight of said seam sealer composition. The first plasticizer mixture helps to adjust the viscosity level and to improve the flexibility of the seam sealer composition. The second plasticizer is present in a range of 1 Wt. % to 3 Wt. %, based on total weight of said seam sealer composition. Preferably, the second plasticizer is Bis(7-methyloctyl) benzene-1,2-dicarboxylate. The second plasticizer acts as feed and used to balance the viscosity of said seam sealer composition.
The embodiments were chosen and described in order to best explain the principles of the present invention and its practical application, to thereby enable others, skilled in the art to best utilize the present invention and various embodiments with various modifications as are suited to the particular use contemplated. It is understood that various omission and substitutions of equivalents are contemplated as circumstance may suggest or render expedient, but such are intended to cover the application or implementation without departing from the spirit or scope of the present invention.
,CLAIMS:
1) A seam sealer composition comprising:
a predefined amount of poly vinyl chloride (PVC) resin mixture having a predefined amount of PVC copolymer resin, a predefined amount of PVC homopolymer resin and a predefined amount of blend resin;
a predefined amount of filler mixture having a predefined amount of coated filler and a predefined amount of non-coated filler;
a predefined amount of adhesion promoter material;
a predefined amount of absorbent material;
a predefined amount of stabilizer material; and
a predefined amount of plasticizer mixture having a first plasticizer mixture and a second plasticizer, the first plasticizer mixture having a primary phthalate free plasticizer and a secondary phthalate free plasticizer in a predefined proportion.

2) The seam sealer composition as claimed in claim 1, wherein the PVC copolymer resin is in a range from about 5 Wt. % to 10 Wt. %, based on total weight of said seam sealer composition.

3) The seam sealer composition as claimed in claim 1, wherein the PVC homopolymer resin is in a range from about 5 Wt. % to 10 Wt. %, based on total weight of said seam sealer composition.

4) The seam sealer composition as claimed in claim 1, wherein the blend resin is in a range from about 3Wt. % to 5 Wt. %, based on total weight of said seam sealer composition.

5) The seam sealer composition as claimed in claim 1, wherein the PVC resin is Chloro ethylene.

6) The seam sealer composition as claimed in claim 1, wherein the coated filler is in a range of 10 Wt. % to 15Wt. % or optionally in range of 10 Wt. % to 25Wt. %, based on total weight of said seam sealer composition.

7) The seam sealer composition as claimed in claim 1, wherein the non-coated filler is in a range of 20 Wt. % to 30 Wt. %, based on total weight of said seam sealer composition.

8) The seam sealer composition as claimed in claim 1, wherein the filler is Carbonic acid calcium salt.

9) The seam sealer composition as claimed in claim 1, wherein the adhesion promoter material is in a range of 3 Wt. % to 6 Wt. %, based on total weight of said seam sealer composition.

10) The seam sealer composition as claimed in claim 1, wherein the adhesion promoter material is 2-[[4-[2-[4-(Oxiran-2-ylmethoxy) phenyl] propan-2-yl] phenoxy] methyl] oxirane.

11) The seam sealer composition as claimed in claim 1, wherein the absorbent material is in a range of 1 Wt. % to 3 Wt. %, based on total weight of said seam sealer composition

12) The seam sealer composition as claimed in claim 1, wherein, the absorbent material is Calcium Oxide.

13) The seam sealer composition as claimed in claim 1, wherein the stabilizer material is in a range of 1 Wt. % to 2 Wt. %, based on total weight of said seam sealer composition.

14) The seam sealer composition as claimed in claim 1, wherein, the stabilizer material is Oxozinc.

15) The seam sealer composition as claimed in claim 1, wherein the predefined proportion of the primary phthalate free plasticizer and the secondary phthalate free plasticizer is 8:2.

16) The seam sealer composition as claimed in claim 1, wherein the primary plasticizer is Tributyl 2-hydroxypropane-1,2,3-tricarboxylate

17) The seam sealer composition as claimed in claim 1, wherein the secondary plasticizer is 8-bromo-9-chlorododec-1-ene.

18) The seam sealer composition as claimed in claim 1, wherein the first plasticizer mixture is present in a range of 20 Wt. % to 25 Wt. %, based on total weight of said seam sealer composition.

19) The seam sealer composition as claimed in claim 1, wherein the second plasticizer is present in a range of 1 Wt. % to 3 Wt. %, based on total weight of said seam sealer composition.

20) The seam sealer composition as claimed in claim 1, wherein the second plasticizer is Bis (7-methyloctyl) benzene-1,2-dicarboxylate.