Description:FIELD OF THE INVENTION
[0001] The present invention relates to a process for preparation of a new generation advanced polycarboxylate ether (APCE) superplasticizer. Specifically, the process for preparation of APCE superplasticizer comprises more than one biomaterial as a starting material. The synthesized APCE is bio-based and has high-water reduction, high early strength, longer workability and good dispersion.

BACKGROUND OF THE INVENTION
[0002] Background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
[0003] In technical fields which entail a high consumption of materials and products, there is a great and increasing demand for bio-based materials and products. Bio-based materials and products are at least partly produced from biological materials, especially from renewable raw materials. They have an advantageous carbon monoxide (CO) balance, since they are based only partly on fossil raw materials, if at all. Moreover, they can be produced in a sustainable and increasingly also inexpensive manner if the underlying biological material is of good availability, especially when by-products or waste materials from agriculture and silviculture are used.
[0004] Specifically in the construction sector, it is desirable to utilize and to use bio-based materials and products, to improve the CO balance and overall to enable more sustainable construction. There is therefore a general need to replace conventional materials and products based on fossil raw materials with bio-based materials and products.
[0005] In the construction sector, large amounts of cements, gypsum, lime and other hydraulically setting compositions are consumed. An important additive in such compositions is organic polycarboxylate ethers. These are comb polymers having a main chain having carboxyl groups, and side chains having polyether groups, especially based on polyethylene oxide and/or polypropylene oxide. They serve particularly as processing aids, namely as dispersants and Superplasticizers. Polycarboxylate ethers are prepared in the prior art by polymerization reactions or polymer-analogous reactions, using conventional mineral oil-based raw materials as starting materials.
[0006] Nowadays, a performance-based admixture is in demand due to the construction sector's rapid growth and the continuous innovation of concrete mix design. Numerous innovative technologies have emerged in the construction industry over the past few generations, including huge templates, sliding molds, pumping concrete, vacuum dehydration concrete, shotcrete, underwater concreting and others. The development of these modern building techniques and systems has led to the advancement of ever-higher standards for concrete industry’s economic growth and construction efficiency. Modern concrete, in particular, needs to perform better in terms of liquefaction, plasticity, temperature resistance, water permeability, density, retarding, rapid setting, maximum strength, and other aspects. To meet the construction industry’s advanced demand basically two types of polycarboxylate ether molecules exist, these are:
1] Water reduction polycarboxylate ether [WRPCE] and
2] Slump retention polycarboxylate ether [SRPCE].
[0007] WRPCE are generally synthesized by free radical polymerization or polymer analogous reaction, made from oil based raw materials belonging to different carboxylic groups, side chains of polyethylene oxide and ethylene oxide. They basically work as dispersants and high range water reducing superplasticizers.
[0008] Conventional dispersants for cementitious and gypsum compositions typically achieve good water reduction, however, they are limited in their ability to retain workability over a long period of time. Usual dispersants are static in their chemical structure over time in hydraulic systems. Their performance is controlled by the monomer molar ratio that is fixed within a polymer molecule. Water reducing effect or dispersing effect is observed upon dispersant adsorption onto the hydraulic particle surface. As dispersant demand increases over time due to abrasion and hydration product formation, which creates more surface area, these conventional dispersants are unable to respond and workability is lost.
[0009] Typically, the issue of extended workability is solved by either re-tempering (adding more water) to the hydraulic compositions or by adding more high range water reducer. Addition of water leads to lower strength and thus creates a need for mixes that are “over-designed in the way of hydraulic binder content. Various types of organic compounds have been used to advantageously alter certain properties of wet hydraulic binder compositions. One class of components, which can collectively be called “superplasticizers”, fluidify or plasticize wet binder compositions to obtain a more fluid mixture. A controlled fluidity is desired. Such that the aggregate used in mortars and concrete does not segregate from the binder paste. Alternatively, the superplasticizers may allow the cement composition to be prepared using a lower water:binder ratio in order to obtain a composition having a desired consistency which often leads to a hardened composition having a higher compressive strength development after setting.
[0010] A good superplasticizer should not only fluidify the wet hydraulic binder composition to which it is added, but also maintain the level of fluidity over a desired period of time. This time should be long enough to keep the wet com position fluid, e.g. in a ready-mix truck while it is on its way to a job site. Another important aspect relates to the period for discharging the truck at the job site and the period needed for the cement composition for being worked in the desired final form. On the other side, the hydraulic mixture cannot remain fluid for a too longtime, that means the set must not greatly be retarded, because this will slow down the work on the job and show negative influences on the characteristics of the final hardened products.
[0011] Conventional examples of superplasticizers are melamine Sulfonate/formaldehyde condensation products, naphthalene Sulfonate/formaldehyde condensation products and lingosulfonates, polysaccharides, hydroxycarboxylic acids and their salts and carbohydrates.
[0012] Currently WRPCE available in the market has water reduction up to 30-35 % and provides retention up to 2-3 h. The main drawbacks of current WRPCE’s are sudden drop down in workability after a certain period of time, initial bleed, delayed cohesiveness in the mix and late early strength. In present WRPCE problems exist such as less water reduction capacity, lower workability and sudden drop in concrete slump which does not meet the present construction industry’s demand.
[0013] Therefore, there is an unmet need in the art to develop WRPCE that overcomes all these shortcomings and also helps enhance the durability properties of concrete. Also, polycarboxylate ethers based on biological materials and especially renewable raw materials are required.

OBJECTIVE OF THE INVENTION
[0014] An objective of the present invention is to provide a process for development of a new generation advanced polycarboxylate ether (APCE) superplasticizer.
[0015] Another objective of the present invention is to provide APCE superplasticizer which is bio-based and having more than one biomaterial as a starting material.
[0016] Another objective of the present invention is to provide APCE which aims to provide longer workability, high water reduction, high early strength, good dispersion and also provide excellent rheology by suppressing water bleeding thereby improving strength of cement composites.

SUMMARY OF THE INVENTION
[0017] The present invention relates to a process for preparing bio-based, new generation advanced polycarboxylate ethers (APCE) superplasticizer, having more than one biomaterial as a starting material.
[0018] In an aspect, the present invention relates to a process for preparing polycarboxylate ethers wherein the process comprises the step of reacting more than one biomaterial as a starting material.
[0019] In an aspect, the present invention relates to a process for preparation of polycarboxylate ethers superplasticizer comprising the steps of:
a) adding more than one biomaterial into deionized water under nitrogen atmosphere;
b) adding hydrogen peroxide to a mixture obtained in step (a) to obtain a reaction mixture;
c) adding carboxylic acid, mercaptoacetic acid and ascorbic acid to the reaction mixture of step b); and
d) neutralizing the reaction mixture of step (c) to pH in a range of 5.8 to 6.8 to obtain the polycarboxylate ethers superplasticizer.
[0020] In an aspect of the present invention, the biomaterial is alkyl acrylamide monomer, or vinyl polyethylene glycol.
[0021] In an aspect of the present invention, the biomaterial contains chain of polyethylene oxide, terminally modified polyethylene oxide, carboxylic acid or a salt thereof.
[0022] In another aspect of the present invention, the biomaterial includes various macromonomer and monomers.
[0023] In another aspect of the present invention, the polymer mass concentration ratio in the process of preparation of APCE is ranging from 30% to 50 %.
[0024] In another aspect of the present invention, the polymerization of the polymer was done at room temperature by using a suitable redox initiator system.
[0025] In another aspect of the present invention, the APCE obtained from the present process offers 20-25% higher early strength when compared the convention polycarboxy ethers.
[0026] In another aspect of the present invention, the APCE has a high water reduction capacity around 40%.
[0027] Various objects, features, aspects and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments.

DETAILED DESCRIPTION OF THE INVENTION
[0028] The following is a full description of the disclosure's embodiments. The embodiments are described in such a way that the disclosure is clearly communicated. The level of detail provided, on the other hand, is not meant to limit the expected variations of embodiments; rather, it is designed to include all modifications, equivalents, and alternatives that come within the spirit and scope of the current disclosure as defined by the attached claims. Unless the context indicates otherwise, the term "comprise" and variants such as "comprises" and "comprising" throughout the specification are to be read in an open, inclusive meaning, that is, as "including, but not limited to."
[0029] When "one embodiment" or "an embodiment" is used in this specification, it signifies that a particular feature, structure, or characteristic described in conjunction with the embodiment is present in at least one embodiment. As a result, the expressions "in one embodiment" and "in an embodiment" that appear throughout this specification do not necessarily refer to the same embodiment. Furthermore, in one or more embodiments, the specific features, structures, or qualities may be combined in any way that is appropriate.
[0030] Unless the content clearly demands otherwise, the singular terms "a," "an," and "the" include plural referents in this specification and the appended claims. Unless the content explicitly mandates differently, the term "or" is normally used in its broad definition, which includes "and/or."
[0031] In some embodiments, the numbers expressing quantities of ingredients, properties such as concentration, reaction conditions, and so forth, used to describe and claim certain embodiments of the invention are to be understood as being modified in some instances by the term “about.” Accordingly, in some embodiments, the numerical parameters set forth in the written description are approximations that can vary depending upon the desired properties sought to be obtained by a particular embodiment. In some embodiments, the numerical parameters should be constructed in light of the number of reported significant digits and by applying ordinary rounding techniques. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of some embodiments of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as practicable.
[0032] The recitation of ranges of values herein is merely intended to serve as a shorthand method of referring individually to each separate value falling within the range. Unless otherwise indicated herein, each individual value is incorporated into the specification as if it were individually recited herein.
[0033] All processes described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g. “such as”) provided with respect to certain embodiments herein is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention otherwise claimed. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the invention.
[0034] The headings and abstract of the invention provided herein are for convenience only and do not interpret the scope or meaning of the embodiments.
[0035] The following discussion provides many example embodiments of the inventive subject matter. Although each embodiment represents a single combination of inventive elements, the inventive subject matter is considered to include all possible combinations of the disclosed elements. Thus if one embodiment comprises elements A, B, and C, and a second embodiment comprises elements B and D, then the inventive subject matter is also considered to include other remaining combinations of A, B, C, or D, even if not explicitly disclosed.
[0036] All publications herein are incorporated by reference to the same extent as if each individual publication or patent application were specifically and individually indicated to be incorporated by reference. Where a definition or use of a term in an incorporated reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply.
[0037] Groupings of alternative elements or embodiments of the invention disclosed herein are not to be construed as limitations. Each group member can be referred to and claimed individually or in any combination with other members of the group or other elements found herein. One or more members of a group can be included in, or deleted from, a group for reasons of convenience and/or patentability. When any such inclusion or deletion occurs, the specification is herein deemed to contain the group as modified thus fulfilling the written description that follows, and the embodiments described herein, is provided by way of illustration of an example, or examples, of particular embodiments of the principles and aspects of the present disclosure. These examples are provided for the purposes of explanation, and not of limitation, of those principles and of the disclosure.
[0038] It should also be appreciated that the present invention can be implemented in numerous ways, including as a system, a method or a device. In this specification, these implementations, or any other form that the invention may take, may be referred to as processes. In general, the order of the steps of the disclosed processes may be altered within the scope of the invention.
[0039] Various terms as used herein are shown below. To the extent a term used in a claim is not defined below, it should be given the broadest definition persons in the pertinent art have given that term as reflected in printed publications and issued patents at the time of filing.
[0040] “Polycarboxylate ethers” are polymers comprising a main chain having carboxylic acid and/or carboxylic acid anhydride monomers, e.g. acrylic acid, methacrylic acid, maleic acid and its anhydride, itonic acid and its anhydride and side chains having polyether groups, especially based on polyethylene oxide (polyethylene glycol; PEG) and/or polypropylene oxide.
[0041] The polycarboxylate ether may be entirely or partly biobased. This depends on the extent to which biomaterials are used in the process of preparation of polycarboxylate ethers.
[0042] The term “biomaterial” means in accordance with the invention that a compound, a material or the like, for example a starting material or a polycarboxylate ether, is a biomaterial as it has been used in biomedical application.
[0043] In a general embodiment, the present invention provides a process for development of high-water reduction, high early strength, biobased and new generation advanced polycarboxylate ether (APCE) superplasticizer for fourth generation construction industry. The APCE superplasticizer synthesized is biobased, having more than one biomaterial as a starting material.
[0044] In an embodiment, the present invention relates to a process for preparation of polycarboxylate ethers superplasticizer comprising the steps of:
a) adding more than one biomaterial into deionized water under nitrogen atmosphere;
b) adding hydrogen peroxide to a mixture obtained in step (a) to obtain a reaction mixture;
c) adding carboxylic acid, mercaptoacetic acid and ascorbic acid to the reaction mixture of step b); and
d) neutralizing the reaction mixture of step (c) to pH in a range of 5.8 to 6.8 to obtain the polycarboxylate ethers superplasticizer.
[0045] In an embodiment of the present invention, the biomaterial is alkyl acrylamide monomer, or vinyl polyethylene glycol.
[0046] In another embodiment of the present invention, the process for preparation of APCE superplasticizer comprises the step of:
a) adding alkyl acrylamide monomer and vinyl polyethylene glycol into deionized water under nitrogen atmosphere;
b) adding hydrogen peroxide to a mixture obtained in step (a) to obtain a reaction mixture;
c) adding carboxylic acid, mercaptoacetic acid and ascorbic acid to the reaction mixture of step b); and
d) neutralizing the reaction mixture of step (c) to pH in a range of 5.8 to 6.8 to obtain the polycarboxylate ethers superplasticizer.
[0047] In another embodiment of the present invention, the biomaterial is selected from the group consisting of polyethylene oxide, terminally modified polyethylene oxide, carboxylic acid or a salt thereof.
[0048] In another embodiment of the present invention, the starting biomaterial used is polyethylene oxide. The polyethylene oxide may have been terminally modified at one end of the poly ethylene oxide chain or at both ends. The term “end” means the two chain ends of the polymer. In a preferred embodiment, the polyethylene oxide has been terminally modified only at one end and has a free hydroxyl group at the other end.
[0049] In another embodiment of the present invention, the carboxylic acid can be acrylic acid, methacrylic acid, itaconic acid and the like.
[0050] In another embodiment of the present invention, the hydrogen peroxide used in the process is 30% hydrogen peroxide.
[0051] In another embodiment of the present invention, the carboxylic acid is added dropwise to the reaction mixture by dissolving the carboxylic acid in water for a period of 1 to 3 hours.
[0052] In another embodiment of the present invention, the carboxylic acid is added dropwise to the reaction mixture by dissolving the carboxylic acid in water for a period of 1 to 3 hours.
[0053] In another embodiment of the present invention, the mercaptoacetic acid and ascorbic acid aqueous solution is added dropwise after addition of carboxylic acid.
[0054] In another embodiment of the present invention, the mercaptoacetic acid and ascorbic acid aqueous solution is added dropwise for a period of 15 to 30 minutes more than the time taken for addition of carboxylic acid in water.
[0055] In another embodiment of the present invention, the aqueous carboxylic acid is added dropwise to the reaction mixture for a period of 1 to 3 hours and the mercaptoacetic acid and ascorbic acid aqueous solution is added dropwise for a period 1 hour 15 minutes to 3 hours 30 minutes.
[0056] According to the present invention, the APCE superplasticizer is synthesized by the grafting of more than one monomer like vinyl branch polyether with varying pendent chain density as macromonomer and other acrylates on unsaturated carboxylic acid or a salt thereof as monomer by free radical copolymerization.
[0057] In another embodiment of the present invention, the APCE is prepared using various macro monomer and monomers ratios with reduced time span, compared to conventional PCE. Also, it has been synthesized by regulating the polymer mass concentration ratio between 30 to 50 % by using demineralized water and polymerization was done at room temperature by using a suitable redox initiator system.
[0058] In another embodiment of the present invention, the polycarboxylate ether is at least 10% biobased, more than 25% biobased, more than 50% biobased, more than 75% biobased, more than 90% biobased, more than 95% biobased, more than 98% biobased or 100% biobased.
[0059] In another embodiment of the present invention, the APCE superplasticizer obtained by the present process workability is reduced down gradually which is a unique feature of our newly designed molecule whereas almost all high-water reduction workability of conventional polycarboxylate ethers suddenly drops down after a certain period of time.
[0060] In another embodiment of the present invention, the synthesized APCE aims to provide longer workability, 20-25% higher early strength, high water reduction capacity around 40%, good dispersion and also provide excellent rheology by suppressing water bleeding thereby improving strength of cement composites.
[0061] In an embodiment of the present invention, the comparative data showing the higher early strength of the APCE is given below.
Compressive strength
(N/mm2) M-60 grade concrete with conventional PCE
(25 % water Reduction) M-60 grade concrete with advanced PCE
(35 % water Reduction) Strength difference (%)
3 days 44.31 50.71 12.62
7 days 52.82 62.06 14.88
28 days 60.13 79.82 24.67

[0062] In an embodiment of the present invention, the advanced polycarboxylate ethers obtained from the present process useful as hydraulic binders which act as dispersants.
[0063] In another embodiment of the present invention, the advanced polycarboxylate ether obtained from the present process can also be used in the form of flakes, powders, chips, pellets, granules or slabs.
[0064] In another embodiment, the present invention relates to a use of the advanced polycarboxylate ethers obtained from the present process as a dispersants.
[0065] While the foregoing describes various embodiments of the disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof. The scope of the invention is determined by the claims that follow. The invention is not limited to the described embodiments, versions or examples, which are included to enable a person having ordinary skill in the art to make and use the invention when combined with information and knowledge available to the person having ordinary skill in the art.
EXAMPLES
[0066] The present invention is further explained in the form of the following examples. However, it is to be understood that the following examples are merely illustrative and are not to be taken as limitations upon the scope of the invention.
[0067] Example 1
Initially 160g of deionized water was added into the three-neck glass reactor, equipped with thermometer, dropping funnel, nitrogen inlet arrangement with stirrer. 169g of vinyl polyethylene glycol was added purged the glass reactor with nitrogen inlet while stirring till complete dissolution. 2.0 g alkyl acrylamide monomer was added and stirred till dissolve. Then 1.2 g of hydrogen peroxide (30% concentration) was added and stirred well. Then 20g of acrylic acid was mixed with 50g of water mix and dripped it into the glass reactor for up to 2 h. Later, 40 g water was added with 1.0g of mercaptoacetic acid and 1.0g of ascorbic acid aqueous solution in to a glass reactor for 30 min more than acrylic acid solution by dropwise manner. After complete dripping, the reaction mixture was kept at thermal insulation for 1h, cooled to room temperature and then neutralized to pH in the range of 5.8 to 6.8. A pale yellow transparent liquid with solid content 43.0 % was obtained.
[0068] Example 2
154g of deionized water was added into the three-neck reactor, equipped with thermometer, dropping funnel, nitrogen inlet arrangement with stirrer. Alkyl acrylamide monomer (2.0g) followed by 174g of vinyl polyethylene glycol were added and purged the nitrogen inlet in the reactor for constant stirring till complete dissolution. Then 1.3g of hydrogen peroxide (30% concentration) was added and stirred well. 22.33g of acrylic acid was mixed with 48g of water mix and dripped it into the glass reactor for up to 2.5 h. Added 40 g water with 1.1g of mercaptoacetic acid and 1.0 g of ascorbic acid aqueous solution in to a glass reactor for 15 min more than acrylic acid solution by dropwise manner. After complete dripping, the reaction mixture was kept for thermal insulation for 1 h, cooled to room temperature and then neutralized to pH in the range of 5.8 to 6.8. A pale yellow transparent liquid with solid content 44.7 % was obtained.
[0069] Example 3
155g of deionized water was added into the three-neck reactor, equipped with thermometer, dropping funnel, nitrogen inlet arrangement with stirrer. Then 1.5g alkyl acrylamide monomer was added and then 186g of vinyl polyethylene glycol was added purged the nitrogen inlet in the reactor for constant stirring till complete dissolution. Then added 1.1g of hydrogen peroxide (30% concentration) and stirred well. 23.20g of acrylic acid was mixed with 40g of water mix and dripped it into the glass reactor for up to 2.5 h, and then added 45g water with 1.1g of mercaptoacetic acid and 1.1 g of ascorbic acid aqueous solution in to a glass reactor for 15 min more than carboxylic acid solution by dropwise manner. After completely dripping, the reaction mixture was kept for thermal insulation for 1 h, cooled to room temperature and then neutralized to pH in the range of 5.8 to 6.8. A pale yellow transparent liquid with solid content 46.4 % was obtained.
[0070] Example 4
143g of deionized water was added into the three-neck reactor, equipped with thermometer, dropping funnel, nitrogen inlet arrangement with stirrer. Then 3.0g alkyl acrylamide monomer was added and then 187g of vinyl polyethylene glycol was added purged the nitrogen inlet in the reactor for constant stirring till complete dissolution. Then 1.1g of hydrogen peroxide (30% concentration) was added and stirred well. Then 28.0g of acrylic acid was mixed with 40g of water mix and drip it in to the glass reactor for up to 2.5 h, and then added 33g water with 1.1g of mercaptoacetic acid and 1.1g of ascorbic acid aqueous solution in to a glass reactor for 15 min more than acrylic acid solution by dropwise manner. After completely dripping, the reaction mixture was kept for thermal insulation for 1 h, cooled to room temperature and then neutralized to pH in the range of 5.8 to 6.8. A pale yellow transparent liquid with solid content 49.85 % was obtained.
[0071] A skilled artisan will appreciate that the quantity and type of each ingredient can be used in different combinations or singly. All such variations and combinations would be falling within the scope of present disclosure.
[0072] The foregoing examples are merely illustrative and are not to be taken as limitations upon the scope of the invention. Various changes and modifications to the disclosed embodiments will be apparent to those skilled in the art. Such changes and modifications may be made without departing from the scope of the invention.

ADVANTAGES OF THE PRESENT INVENTION
[0073] The present invention provides a process for developing biobased, new generation advanced polycarboxylate ether (APCE) superplasticizer for the fourth generation construction industry.
[0074] The present invention provides APCE which aims to provide longer workability, 30-35% higher early strength, high water reduction capacity around 40%, good dispersion and also provide excellent rheology by suppressing water bleeding thereby improving strength of cement composites.

, Claims:1. A process for preparing polycarboxylate ethers, wherein the process comprises the step of reacting more than one biomaterial as a starting material; wherein the polycarboxylate ethers obtained has no sudden drop down in workability.

2. A process for preparing polycarboxylate ethers, wherein the process comprises the steps of:
a) adding more than one biomaterial into deionized water under nitrogen atmosphere;
b) adding hydrogen peroxide to a mixture obtained in step (a) to obtain a reaction mixture;
c) adding carboxylic acid, mercaptoacetic acid and ascorbic acid to the reaction mixture of step b); and
d) neutralizing the reaction mixture of step (c) to pH in a range of 5.8 to 6.8 to obtain the polycarboxylate ethers superplasticizer.

3. The process as claimed in claim 1 or 2, wherein the biomaterial is alkyl acrylamide monomer, or vinyl polyethylene glycol.

4. The process as claimed in claim 1 or 2, wherein the biomaterial contains a chain of polyethylene oxide, terminal position is modified by polyethylene oxide, carboxylic acid or a salt thereof.

5. The process as claimed in claim 2, wherein the hydrogen peroxide is 30% hydrogen peroxide.

6. The process as claimed in claim 2, wherein the mercaptoacetic acid and ascorbic acid is in a ratio ranging from 1:1 to 1:3.

7. The process as claimed in claim 2, wherein the polycarboxylate ether reduces water requirement up to 40%.

8. The process as claimed in claim 2, wherein the polycarboxylate ether is at least 10% biobased.