FORM 2
THE PATENTS ACT, 1970
(39 OF 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See section 10; rule 13)
AN ADDITIVE TO IMPROVE PROCESSING CHARACTERISTICS OF POLYOLEFIN
FINE RESEARCH & DEVELOPMENT CENTRE PVT LTD
A company incorporated under the laws of India having their office at Plot A 28, Millenium Business Park, Mahape MIDC, Navi Mumbai 400 701.
The following specification particularly describes the invention and the manner in which it
is to be performed

AN ADDITIVE TO IMPROVE PROCESSING CHARACTERISTICS OF POLYOLEFIN
The present invention relates to an additive which improves the processing characteristics of polyolefin.
The additive is metal salt(s) of fatty acyl α- hydroxy carboxylic acid, compound of formula 1,

wherein RCO is the acyl radical of a saturated fatty acid comprising 16 to 22 carbon atoms, n is the average no of a-hydroxy propanoyl groups ranging from 1 to 5 and M is metal(s). The additive may be added at the end of the polymerization zone and/or downstream process for improving the processing characteristics of polyolefin.
BACKGROUND OF THE INVENTION
United States Patent Number 2789992 prepares fatty acid lactylate composition of compound of formula 1 and its alkaline earth metal or alkali metal salts; and discloses its use in bakery industry as dough conditioners.

United States Patent Number 2733252 discloses compound of formula 1 as plasticizers, emulsifiers, biologically active agents and a number of other purposes.
United States Patent Number 3144436 improves processing characteristics of polymer with organic peroxide. However, the additive of the present invention avoids use of peroxides.
United States Patent Number 4366280 discloses use of calcium stearoyl lactylate with antioxidants to stabilize polymers.
United States Patent Number 5198506 prepares homogenous free-flowing polyolefin by using liquid organic peroxide. However, the additive of the present invention avoids use of peroxides.
European Patent Number 1458768B1 discloses that the use of aliphatic acid metal salt during compounding may result in build-up of reaction products, such as aliphatic acids, e.g. fatty acids, in the recycled monomers and process diluents thereby leading to reduced polymerization rates and additional costs in cleaning up recycle lines. In addition, during processing at high temperature the corresponding aliphatic acid may migrate through the polymer and sweat out of the polymer onto processing equipment resulting in reduced processing and product performance, and requiring cleaning of equipment. Further, the aliphatic metal salts are not readily miscible with or dissolvable in polymer process streams under process conditions and as such are not very effective and need to be added in relatively large amounts, which also increases the production cost. However, the use of additive of the present invention in polyolefin will avoid the abovementioned drawbacks.
A number of publications disclose use of compound of formula 1 along with polymer additives such as phenols to stabilize polymers.
We have surprisingly found that additive, compound of formula 1, increases melt flow index and decreases torque of polyolefin without (a) adding peroxides,

(b) degrading the polyolefin and
(c) affecting mechanical properties of the polyolefin.
The polyolefin with improved processing characteristics can then be used as high flow polyolefin for the manufacture of commodities.
OBJECT OF THE INVENTION
The object of the present invention is to provide an additive to improve processing characteristics of polyolefin. A further object of the invention is to avoid the use of hazardous organic peroxides in polyolefins.
The polyolefins prepared by the use of additive of the present invention, have superior processing characteristics such as melt flow index and torque with comparable mechanical properties to the virgin polyolefin. The polyolefin with improved processing characteristics prepared by using additive of the present invention is suitable for manufacturing commodities which use high flow polyolefin.
The improved processing characteristics with comparable rheological properties of the improved polyolefin is industrially favorable as it helps in reducing the cycle time, increasing the output of commodities, and reducing power consumption,

SUMMARY OF THE INVENTION
An additive for improving the processing characteristics of polyolefin comprising metal salt(s) of fatty acyl a-hydroxy carboxylic acid, compound of formula 1,

wherein RCO is the acyl radical of a saturated fatty acid comprising 16 to 22 carbon atoms, n is the average no of a-hydroxy propanoyl groups ranging from 1 to 5 and M is metal(s).
The polyolefin obtained by the addition of additive of the present invention has improved processing characteristics.
DESCRIPTION OF THE INVENTION
It is known in the art that melt flow index of polyolefin can be controlled by the addition of hazardous organic peroxides which will reduce the molecular weight of the polymer. Usually an organic peroxide is added to the polyolefin which is then heated to the organic peroxide's decomposition temperature where the organic peroxide proceeds to break the long polyolefin polymer chains apart thus decreasing the mechanical properties. Further, during peroxide cracking, active sites are created which may result in undesirable side reactions leading to degradation of polymer causing unacceptable odour and colour to the polymer.

A wide variety of peroxides are available viz. 3,6,9-triethy!-3,6,9-trimethyl-l,4,7—
triperoxonane, di(3-methoxybutyl) peroxydicarbonate, 2,5-dimethyl-2,5-di(2-
ethylhexanoylperoxy)hexane, 2,2-di(4,4-di(tert-butylperoxy)cyclohexyl)propane, [2,5 dimethyl-2, 5-bis(t-butylperoxy) hexane] and the like. Although controlled rheology (CR) resins made with the above-mentioned peroxides exhibit good processing characteristics, these resins give off objectionable odour.
We have now surprisingly found a thermally stable, relatively non hygroscopic, non hazardous, easy to handle additive which when used in polyolefin improves its processing characteristics, provides comparable mechanical properties with no objectionable odor. The additive of the invention avoids generation of active sites in the polyolefin and also retains the chain length of the polyolefin,
According to one embodiment of the present invention the additive of the present invention comprises compound of formula 1,

wherein RCO is the acyl radical of a saturated fatty acid comprising 16 to 22 carbon atoms, n is the average no of α-hydroxy propanoyl groups ranging from 1 to 5 and M is metal(s); which improves processing characteristics of the polyolefin.
In the present invention the term polyolefin refers to polyethylene, polypropylene and ethylene vinyl acetate.
The polyolefin is mixed with about 0.1 to 3% weight of the additive at the end of the polymerization zone and/or downstream process to prepare polyolefin with improved
processing characteristics.

The additive used in the present invention may comprise metal salts selected from sodium, potassium, calcium, magnesium, aluminum, zinc and the like. More preferably the additive used in the present invention is a mixture of alkaline earth metals and alkali metal salts. The ratio of alkaline earth metals to alkali metal salts may be selected from 1:9 to 9:1 parts by weight.
Additive A as referred to herein is alkaline earth and/or alkali metal salts of compound of formula 1 wherein calcium to sodium salt is in the ratio of about 1:1 parts by weight.
The additive used in the present invention is thermally stable and can be used for compounding polyolefin in high shear lines. Additive A is stable at the processing conditions/temperature of the polyolefin.
According to another embodiment of the present invention the method for preparing polyolefin with improved processing characteristics comprises admixing the additive of the present invention comprising compound of formula 1,

wherein RCO is the acyl radical of a saturated fatty acid comprising 16 to 22 carbon atoms, n is the average no of a-hydroxy propanoyl groups ranging from 1 to 5 and M is metal(s); with polyolefin and melting the mixture under thermal mechanical action such as extrusion, injection molding, Haake conditions and the like. The polyolefin prepared using the additive of the

present invention has improved processing characteristics such as melt flow index and average torque.
The melt flow index of polyoiefin with improved processing characteristics prepared according to the present invention increases proportionately with concentration of the additive. The melt flow of the polyoiefin with improved processing characteristics is increased about 3 to 5 fold when the concentration of the additive is increased from 0.1 to 3% by weight of the polyoiefin.
The average torque of polyoiefin with improved processing characteristics decreases proportionately with concentration of the additjve. The average torque of the polyoiefin with improved processing characteristics is decreased by 40 to 60% when the concentration of the additive is increased from 0.1 to 3% by weight of the polyoiefin.
The mechanical properties such as impact strength, flexural modulus, flexural strength, elongation at length and tensile strength of the polyoiefin with improved processing characteristics obtained by using the additive of the present invention are comparable to virgin polyoiefin.
The use of additive of the present invention results in controlled rheology polyoiefin resin.
According to yet another embodiment of the present invention is the polyoiefin with improved processing characteristics of the present invention comprising additive, compound of formula 1,


wherein RCO is the acyl radical of a saturated fatty acid comprising 16 to 22 carbon atoms, n is the average no of α-hydroxy propanoyl groups ranging from 1 to 5 and M is metai(s).
The polyolefin used is of injection molding and extrusion grade polyolefin, preferably injection molding grade.
The melt flow index of polyolefin with improved processing characteristics prepared according to the present invention increases proportionately with concentration of the additive. The melt flow of the polyolefin with improved processing characteristics is increased about 3 to 5 fold when the concentration of the additive is increased from 0.1 to 3% by weight of the polyolefin.
The average torque of polyolefin with improved processing characteristics decreases proportionately with concentration of the additive. The average torque of the polyolefin with improved processing characteristics is decreased by 40 to 60% when the concentration of the additive is increased from 0.1 to 3% by weight of the polyolefin.
The mechanical properties such as impact strength, flexural modulus, flexural strength, elongation at length and tensile strength of the polyolefin with improved processing characteristics obtained by using the additive of the present invention are comparable to virgin polyolefin.
The use of additive of the present invention results in controlled rheotogy polyolefin resin.
The polyolefin with improved processing characteristics obtained by use of the additive of the present invention helps in reducing the cycle time, increases output and reduces power consumption during manufacturing of polyolefin commodities-

DESCRIPTION OF FIGURES
Figure 1 is the crossover graph of effect of Additive of the present invention on MFI and Torque
with data from Example 2
Figure 2 is the Spiral flow data at standard injection pressure
Figure 3 is the Spiral flow data at reduced injection pressure
DEFINITION OF TERMS
Homopolvmers and Copolymers
Homopolymer is a polymer with a single monomer e.g. polyethylene.
Copolymer is formed by polymerizing more than one monomer. For example ethylene and propylene can be copolymerized to produce a polymer that has two kinds of repeating units.
Random copolymers contain repeating monomers arranged in a purely random fashion.
Random copolymers are classified on the basis of the way monomers are arranged along the polymer chain, as shown in the figure beiow.
[... A—B—B—A—A—A—B—A—B—B---------]
Random copolymer
[ ... —A—B—A—B—A—B—A—B—A™B ...]
Regular copolymer
... A—A—A—A—B—B—B—B—A—A—B—B—B B—A—A ...]
Block copolymer
[ ... A—A—A—A—A—A—A—A—A—A ...]
B—B—B—B—B ...
Graft copolymer
Regular copolymers contain a sequence of regularly alternating repeating units. The repeating units in block copolymers occur in blocks of different lengths.

Graft copolymers have a chain of one repeating monomer grafted onto the backbone of another. This is also known as impact grade polymer.
Melt flow index or MFI is a measure of the ease of flow of the melt of a thermoplastic material. It is defined as the mass of polymer, in grams, flowing in ten minutes through a capillary of a specific diameter and length by a pressure applied via prescribed alternative gravimetric weights for alternative prescribed temperatures. The method is described in the similar standards ASTM D1238 and ISO 1133.
Fusion Time and Fusion Torque When Polymer compound is mixed under appropriate conditions of heat and shear, a fused mass is produced. This mass has certain melt characteristics which can be defined with a torque rheometer operated under fixed conditions of shear and temperature. Fusion time is the time required to get a molten mass at a certain temperature and shear with the fixed mass. Fusion torque is the Torque at this point i.e. at Fusion Time.
Equilibrium Torque or Average torque is the torque where the molten polymer will have a constant viscosity with time.
Haake Condition: The temperature, rotor speed and mass of the polymer are three parameters ofHaake.
Injection Conditions: The temperature, injection time and pressure, holding or cooling time are
the parameters of Injection.
Tensile Strength: Ultimate tensile strength (UTS), often shortened to tensile strength (TS) is the maximum stress that a material can withstand while being stretched or pulled before failing or breaking. Tensile strength is the longitudinal stress required to break a prescribed specimen divided by the original cross-sectional area at the point of rupture within the gauge boundaries sustained by the specimen during the test.

Elongation at break: Elongation at break is the fractional increase in length of a material stressed intension.
Flexural strength: Flexural strength is defined as a material's ability to resist deformation under load. The transverse bending test is most frequently employed, in which a specimen having either a circular or rectangular cross-section is bent until fracture or yielding using a three point flexural test technique. The flexural strength represents the highest stress experienced within the material at its moment of rupture. It is measured in terms of stress, here given the symbolcr.
Flexural Modulus: In mechanics, the flexural modulus or bending modulus is the ratio of stress to strain in flexural deformation or the tendency for a material to bend. It is determined from the slope of a stress-strain curve produced by a flexural test (such as the ASTM D 790), and uses units of force per area. It is an intensive property.
Notched Izod impact Test: Izod impact testing is an ASTM standard method of determining the impact resistance of materials. An arm held at a specific height (constant potential energy) is released. The arm hits the sample and breaks it. From the energy absorbed by the sample, its impact energy is determined. A notched sample is generally used to determine impact energy and notch sensitivity..
Spiral flow method: A method for determining the flow properties of a thermoplastic or thermosetting resin based on the distance it will flow, under controlled conditions of pressure and temperature, along a spiral runner of constant cross section.
%Crystallinitv: Crystallinity refers to the degree of structural order in a solid. In a crystal, the atoms or molecules are arranged in a regular, periodic manner. The degree of crystallinity has a big influence on hardness, density, transparency and diffusion. Crystallinity can be measured using x-ray diffraction, but calorimetric techniques are also commonly used.

Polydispersity: It is used as a measure of the broadness of a molecular weight distribution of polymer & is ratio of weight average molecular weight to the number average molecular weight. The term polydispersity, represented by the symbol € which can refer to either molecular mass or degree of polymerization. It can be calculated using the equation DM - Mw/Mn, where Mw is the weight-average molar mass and Mn is the number-average molar mass. It can also be calculated according to degree of polymerization, where Dx = Xw/Xn, where Xw is the weight-average degree of polymerization and Xn is the number-average degree of polymerization. In certain limiting cases where DM = Dx, it is simply referred to as D. The larger the poydispersity index, broader the molecular weight distribution (MWD).
Shear stress: A shear stress, (T) is defined as the component of stress coplanar with a material cross section. Shear stress arises from the force vector component parallel to the cross section. Normal stress, on the other hand, arises from the force vector component perpendicular or anti-parallel to the material cross section on which it acts. A shear stress T is applied to the top of the rectangle while the bottom is held in place. This stress results in a strain or deformation, changing the rectangle into a parallelogram: The area involved would be the top of the parallelogram.
The formula to calculate average shear stress is:

where:
T = the shear stress;
F = the force applied;
A = the cross-sectional area of material with area parallel to the applied force vector.

1. Shear rate: The shear rate for a fluid flowing between two parallel plates, one moving at a constant speed and the other one stationary is defined by

where:
• γ is the shear rate, measured in reciprocal seconds;
• v is the velocity of the moving plate, measured in meters per second;
• h is the distance between the two parallel plates, measured in meters.
Viscosity: The viscosity of a fluid is a measure of its resistance to gradual deformation by
shear or tensile stress
%wt loss in TGA: % weight loss in TGA stands for loss of weight expressed in percentage when the substance is heated isothermally/dynamically under control heating rate & controlled atmosphere by thermogravimetric analysis (TGA).
Thermogravimetric analysis or thermal gravimetric analysis (TGA) is a method of thermal analysis in which changes in physical and chemical properties of materials are measured as a function of increasing temperature (with constant heating rate), or as a function of time (with constant temperature and/or constant mass loss). TGA can provide information about physical phenomena, such as second order phase transitions, including vaporization, sublimation, absorption, adsorption, and desorption. Likewise, TGA can provide information about chemical phenomena including chemisoprtions, desolvation [especially dehydration), decomposition. and solid-gas reactions (e.g., oxidation or reduction).

EXAMPLES
Homopolypropylene was compounded with additive A and subjected to various studies as
exemplified below
Example 1: Melt Flow Index study

Form 1 Form 2 Form 3 Form 4 Form 5 Form 6
Homopolypropylene I.M. grade 100 100 100 100 100 100
Additive A %wt 0.25 0.5 0.75 1.0 1.5 2.0
Haake conditions: @ 160°C / 40 RPM / 45 gm / 15 min
Avg. Torque, Nm 3,70 3.50 2.80 2.10 1.80 1.60
MFI 11.0 12.0 35.0 65.0 72.0 80.0
Example 2: Homopolypropylene injection molding grade with 1%. Additive A

Sample Fusion Time MFI, g/10 Shear Stress Shear Rate Viscosity (Pa
(sec.) min., 230°C (Pa) (1/sec.) Sec.)
Homopolypropylene
I.M. grade
(After Injection) 8.86 1127 19510 28r16 692.8
Homopolypropylene
I.M. grade
+ Additive A,
(After Haake) 3.13 31.99 19510 79.92 244.17
Homopolypropylene
I.M. grade
+ Additive A,
(Haake followed by
Injection) 2.74 36.41 19510 90.96 214.5

Example 3 '. Homopolypropylene injection molding grade with 1%. Additive A

Sample Fusion Time MFI, g/10 Shear Stress Shear Rate Viscosity (Pa
(sec.) min., 230°G (Pa) (1/sec.) Sec.)
Homopolypropylene
I.M. grade
(After Injection) 9.0 11.0 19510 28.0 693.0
Homopolypropylene
I.M. grade
+ Additive A,
(After Kneading) 3.0 65.0 19510 151.0 146.0
Homopolypropylene
I.M. grade
+ Additive A,
(Kneading followed
by Injection) 2.8 70.0 19510 185.0 | 110.0
Additive A shows substantial flow improvement in presence of shear Example 4: Mechanical Properties

Property ASTM Method Unit Value
Homopolypropylene I.M grade Polypropylene + 1% Additive A
Tensile strength A5TM D638 Mpa 32 33
Elongation @yield ASTM D638 % 8 6
Flexural Strength ASTM D790 Mpa 28 26
Flexural Modulus ASTM D790 Mpa 1100 1120
Notched Izod impact Strength ASTM D256 J/m 27 26
Additive A provides homopolypropylene with comparable mechanical properties to virgin homopolypropylene.

Example 5 : Evaluation of homopolypropylene compounded material (with 1% Additive A) vs. Homopolypropylene using Spiral Flow
1. Polypropylene Homopolymer - Injection molding (11 MFI) = PP
2. Polypropylene Homopolymer Injection Molding {11 MFI) + 1% Additive A Machine Used: ARBURG 320C
Temperature profile:
Feed zone 200°C
Compression Zone 205, 210, 215°C
Nozzle 220°C
Mold Temperature 45°C Injection Flow 25 ccm/s Cooling Time 15 sec. Dosage volume 35 ccm

Trial No. Pressure (bar) Increase in length
of PP + Additive A
vsPP % Increase in length
Stage 1 Stage 2 PP PP +
Additive A
Length Length Length
1 1400 1300 85.6 115.0 + 35+
2 1300 1200 78.0 115.0 + 32+
3 1200 1100 71.1 110.05 55
Maximum length of the mould is 115cm
PP + Additive A shows about 35% increase in length.

Example 6:

Additive A increases %crystallinity Example 7 : Thermal Stability byTGA

SAMPLE MELTING (Tm) Cooling (Tm) crystallization
Crystallinity % Peak°C
Homopolymer PP (10MFI) 50.32 109.80
Homopolymer PP (10MFI) + 1% additive A 63.27 112.50
Homopolymer PP (10MFI) + 2% additive A 64.80 114.00

Temperature °C % Weight loss in Nitrogen Atmosphere
Homopolymer PP (10MFI) Homopolymer PP (10MFI) + 1% additive A
50 0.00 0.02
100 0.00 0.04
150 0.00 0.07
200 0.00 0.09
250 0.00 0.13
300 0.07 0.13
350 0.25 0.29
Additive A is thermally stable upto 350°C in PP

Claims
1. An additive for improving the processing characteristics of polyolefin comprising metal salt{s) of fatty acyl α-hydroxy carboxylic acid, compound of formula 1,

wherein RCO is the acyl radical of a saturated fatty acid comprising 16 to 22 carbon atoms, n is the average no of a- hydroxy propanoyl groups ranging from 1 to 5 and M is metal(s).
2. An additive for improving the processing characteristics of polyolefin as claimed in claim 1 wherein the metal salt(s) is selected from sodium, potassium, calcium, magnesium, aluminum, zinc and the like.
3. An additive for improving the processing characteristics of polyolefin as claimed in claim 1 wherein the metal salt(s) is an alkaline earth metal and/or alkali metal salt.
4. An additive as claimed in claim 3 with the proviso that when the metal salts are alkaline earth metal salts and alkali metal salts, the ratio of alkaline earth metal salts to alkali metal salts is 1:9 to 9:1 parts by weight.

5. An additive for improving the processing characteristics of polyolefin as claimed in claim 1 wherein the polyolefin additive is added at the end of the polymerization zone and/or downstream process.
6. An additive as claimed in claim 1, added in a concentration of about 0.1 to 3% by weight of the polyolefin.
7. An additive for improving the processing characteristics of polyolefin as claimed in claim 1 wherein the processing characteristics are melt flow index and torque.
8. An additive as claimed in claim 7 wherein the melt flow index of the polyolefin with improved processing characteristics increases proportionately by increasing the concentration of the additive.
9. An additive as claimed in claim 8 wherein the melt flow index increases about 3 to 5 fold when the concentration of the additive is increased from 0.1 to 3% by weight of the polyolefin.
10. An additive as claimed in claim 7 wherein the average torque of polyolefin decreases proportionately with increasing concentration of the additive.
11. An additive as claimed in claim 10 wherein the average torque of polyolefin is decreased by 40 to 60% when the concentration of the additive is increased from 0.1 to 3% by weight of the polyolefin.
12. An additive as claimed in claim 1 wherein the additive retains the mechanical properties of polyolefin selected from tensile strength, elongation at break, flexural strength, flexural modulus and impact strength.
13. An additive as claimed in claim 12 to obtain controlled rheology polyolefin resin.

14. An additive as claimed in claim 1 wherein the polyolefin is selected from polyethylene, polypropylene and ethylene vinyl acetate.
15. An additive as claimed in claim 14 wherein the polyolefin is selected from injection molding and extrusion grades.
16. An additive as claimed in claim 15 wherein the polyolefin is injection molding grade homopolyolefin.
17. An additive as claimed in claim 15 wherein the polyolefin is injection molding grade random polyolefin.
18. A polyolefin with improved processing characteristics obtained by the addition of the additive as claimed in claim 1.
19. A polyolefin with improved processing characteristics obtained by the addition of the additive as claimed in claims 1 to 17.
20. A polyolefin as claimed in claim 18 to 19 wherein the polyolefin obtained on addition of the additive is free of peroxide and chemical emissions.