Process for producing a grafted polyolefin

Abstract

A process for producing a grafted polyolefin having improved yellowness characteristics, the process comprising reacting a mixture of (i) at least one polyolefin, (ii) at least one monomer selected from one or more acid compounds having the following general chemical formula (I) or formula (II), wherein in formula (I) and formula (II), neither R1 nor R2 is H, either R1 or R2 is H, at least one of R1 and R2 is alkyl or alkenyl having 1 to 20 carbon atoms, and R1, R2, or both R1 and R2 may further contain an ester, a heteroatom, an aromatic compound, or a halogen, and (iii) at least one free radical initiator for forming the grafted polyolefin, the grafted polyolefin having a yellowness index YIE313 of less than 30. 【Chemical 1】 JPEG2025524036000010.jpg39170

Description

Technical Field

[0001] The present invention relates to a process for producing a grafted polyolefin. More specifically, the present invention relates to a grafting process for producing a grafted polyolefin by grafting a polyolefin with methyl / dimethyl maleic anhydride in order to reduce the yellowing of the grafted polyolefin after grafting the polyolefin with methyl / dimethyl maleic anhydride.

Background Art

[0002] For example, in many packaging applications such as food, pharmaceuticals, cosmetics, transportation, electronic components, and metal laminates, polyolefins need to be bonded to different substrates, and thus a bonding layer adhesive is required. Conventionally, maleic anhydride grafted polyolefin (MAH-g-polyolefin) has been widely used in bonding layer adhesives.

[0003] MAH-g-polyolefin is usually produced by grafting maleic anhydride (MAH) onto a polyolefin backbone using an organic peroxide via high-temperature biaxial screw extrusion molding. Although the reason is unclear, the addition of peroxide often causes an undesired degree of yellowness.

[0004] In some applications sensitive to color, low-color or colorless materials are required, but in MAH-g-polyolefin and its related unexpected products, undesired yellowing, or even dark yellowing, often occurs. Such materials with undesired yellowing are not desirable for use in color-sensitive applications.

[0005] In some cases, solutions to color problems have been attempted by adding specific additives to MAH-g-polyolefin. For example, U.S. Patent No. 6,380,320 (B1) discloses preparing an anhydride grafted polymer having improved color characteristics by mixing a polyolefin, an anhydride-providing monomer, and an oxo-boron compound additive in an extruder and then extruding the resulting anhydride grafted polymer into a molded article. Although some success has been achieved in reducing the yellowness of the anhydride grafted polymer, there is still a need for lower color or colorless materials for use in color-sensitive applications. Therefore, it is desirable to provide an anhydride grafted polyolefin with reduced yellowness for use in color-sensitive applications using different compositions, either in addition to MAH-g-polyolefin alone or together with other additives.

[0006] U.S. Patent No. 5,728,776 (A) discloses a process for preparing a graft polyolefin by melt-kneading (a) a polyolefin (A), (b) an unsaturated carboxylic acid anhydride which is a radical polymerizable monomer heat-treated at 50 to 250 °C before the graft reaction (B), and (c) a radical polymerization initiator (C). Component (A) is polypropylene. The unsaturated carboxylic acid anhydride has a cyclic anhydride structure and is at least one selected from maleic acid, fumaric acid, itaconic acid, and citraconic acid. The unsaturated carboxylic acid is at least one selected from MAH, itaconic anhydride, citraconic anhydride, and cyclopentanedicarboxylic anhydride. Component (C) is an organic peroxide.

[0007] Chinese Patent No. 5859970(A) discloses a method for improving the grafting efficiency of polyolefins. This method includes weighing a polyolefin, a polar monomer (a part of the polar monomer is present in a solvent), an initiator, and an antioxidant according to parts by weight. This method includes adding an initiator to anhydrous ethyl alcohol, a polyolefin, an antioxidant, and a polar monomer solution in a high-speed mixer and uniformly mixing them. After adding a volatile solvent of the polar monomer, the resulting mixture is added to an extruder hopper. The temperature of each section of the extruder is 220°C to 140°C, and the extruder maintains a main screw rotation speed of 60 rpm to 400 rpm and a feed screw speed of 10 rpm to 80 rpm. At the same time, an anhydrous ethyl alcohol solution of the initiator at different speeds is pumped into an extruder having different heating sections. Then the resulting extrudate is cooled, dried, and cut to obtain polar monomer graft-modified polyolefin particles.

[0008] The above two references disclose improvements in the grafting method of polyolefins. One of the grafting components selected in the process disclosed in the above references may be MAH. However, obtaining a low-color or colorless grafted polyolefin product is not disclosed, and the above references do not mention that products having an improved color can be produced using methyl / dimethyl maleic anhydride. The above references do not disclose using methyl / dimethyl maleic anhydride instead of MAH to reduce and / or solve the color problem. Summary of the Invention

[0009] One embodiment of the present invention relates to a process for producing a grafted polyolefin that includes grafting a polyolefin with methyl / dimethyl maleic anhydride such that the grafted polyolefin has improved yellowness characteristics. A process for producing a grafted polyolefin having improved yellowness characteristics includes (i) at least one polyolefin, and (ii) at least one monomer, wherein the at least one monomer is selected from one or more acid compounds having the following general chemical formula (I) or (II),

[0010]

Chemical formula

[0011] In some embodiments, the process of the present invention first provides the following components: (i) at least one polyolefin, (ii) at least one monomer, for example, at least one monomer having formula (I) or formula (II), and (iii) at least one free radical initiator. Second, at least one polyolefin is mixed with at least one monomer such as a monomer selected from the group consisting of 3-methylfuran-2,5-dione, 3,4-dimethylfuran-2,5-dione, or combinations thereof, and at least one free radical initiator to form a reactive mixture. Then, the mixture is reacted or allowed to react to form a grafted polyolefin. The resulting grafted polyolefin advantageously exhibits a yellowness index YIE313 of less than 30. Accordingly, the resulting grafted polyolefin can be used to produce films or other articles having low yellowness, which can in turn be used in color-sensitive applications that require low-color or colorless materials.

[0012] One object of the present invention is to reduce color formation during the grafting of anhydrides onto polyolefins. Methyl / dimethyl maleic anhydride has been found to reduce the yellowing of polyolefins after grafting compared to polyolefins grafted with MAH. Without being bound to any particular theory, 1 Based on 1H NMR (proton nuclear magnetic resonance) analysis and pyrolysis results, it is theorized that the mechanism of color formation in MAH grafting may be the result of phenolic and quinone products present in the final grafted polyolefin prepared by MAH grafting. On the other hand, methyl / dimethyl maleic anhydride grafting is thought to suppress the formation of phenolic and quinone products and thus provide an anhydride-grafted polyolefin product with better color performance.

Embodiments for Carrying Out the Invention

[0013] The temperature used in this specification is in degrees Celsius (°C).

[0014] In this specification, "room temperature (RT)" and "ambient temperature" mean a temperature in the range of 20°C to 26°C, unless otherwise specified.

[0015] As used in this specification, the term "composition" refers to a mixture of the materials that make up the composition, as well as reaction products and decomposition products formed from the materials of the composition.

[0016] The terms "comprising", "including", "having", and their derivatives are not intended to exclude the presence of any additional components, steps, or procedures, whether or not specifically disclosed. To avoid any ambiguity, all compositions claimed through the use of the term "comprising" may contain any additional additives, adjuvants, or compounds, whether polymeric or not, unless the contrary is stated. In contrast, the term "consisting essentially of" excludes any other components, steps, or procedures from the scope of any previous description, except those that are not essential to the operation. The term "consisting of" excludes any component, step, or procedure not specifically depicted or enumerated. The term "or" refers to the listed members individually and in any combination, unless otherwise specified. The use of the singular includes the use of the plural, and vice versa.

[0017] The numerical ranges disclosed in this specification include all values from the lower limit to the upper limit (including the lower and upper limits). In the case of ranges containing explicit values (e.g., a range of 1, or 2, or 3 - 5, or 6, or 7), any sub-range between any two explicit values is included (e.g., the above range 1 - 7 includes sub-ranges 1 - 2, 2 - 6, 5 - 7, 3 - 7, 5 - 6, etc.).

[0018] As used throughout this specification, the following abbreviations have the following meanings, unless otherwise clearly indicated from the context: "=" means "equal to" or "equivalent to", "<" means "less than", ">" means "greater than", "≦" means "less than or equal to", "≧" means "greater than or equal to", "@" means "at", ppm = parts per million, ppb = parts per billion, ppt = parts per trillion, "BV / hr" = bed volume / hour, "MT" = metric ton, g = gram, mg = milligram, Kg = kilogram, L = liter, g / L = grams per liter, μL = microliter, "g / cm 3 " or "g / cc" = grams per cubic centimeter, g / 10 min = grams per 10 minutes, mg / mL = milligrams per milliliter, "kg / m 3 = kilograms per cubic meter, ppm = parts per million by weight, pbw = parts by weight, rpm = revolutions per minute, m = meter, mm = millimeter, cm = centimeter, μm = micron or micrometer, nm = nanometer, min = minute, s = second, ms = millisecond, hr = hour, Pa = Pascal, MPa = megapascal, Pa·s = Pascal second, mPa·s = millipascal second, g / mol = grams per mole, g / eq = grams per equivalent, M n = number average molecular weight, M w = weight average molecular weight, pts = parts by weight, 1 / s or per second -1 = reciprocal of second [s -1 , °C = Celsius temperature, °C / min = Celsius temperature per minute, psi = pounds per square inch, kPa = kilopascal, % = percent, vol% = volume percent, mol% = mole percent, and wt% = weight percent.

[0019] Specific embodiments of the present invention are described below in this specification. These embodiments are provided so that this disclosure is detailed and complete and fully conveys the scope of the subject matter of the present invention to those skilled in the art.

[0020] Unless otherwise specified, unless otherwise implied by the context, or unless otherwise conventional in the art, all percentages, parts, ratios, and like amounts are by weight, all temperatures are in °C, and all test methods are the latest at the time of filing of the present disclosure.

[0021] Generally, the process of the present invention for producing a grafted polyolefin having improved yellowness characteristics includes reacting a reaction mixture or enabling the reaction mixture to react, the reactive mixture comprising the following components, namely, (i) at least one polyolefin, (ii) at least one monomer, wherein at least one monomer is selected from the group consisting of 3-methylfuran-2,5-dione, 3,4-dimethylfuran-2,5-dione, or combinations thereof, and (iii) at least one free radical initiator. By mixing at least one polyolefin, at least one monomer, and at least one free radical initiator under process conditions such as high temperature, a grafted polyolefin is formed, and the grafted polyolefin has a yellowness index YIE313 of less than 30. Other optional additives or agents, or compounds, optional component (iv) can be added to the above polyolefin composition as needed.

[0022] Component (i) of the formulation or composition used to produce the grafted polyolefin of the present invention having improved yellowness characteristics is at least one polyolefin. Examples of component (i), which are polyolefins useful in the present invention, include polyethylene, polypropylene, styrene-ethylene-butene-styrene, alpha olefin homo- or copolymers, ethylene octene copolymers, ethylene hexene copolymers, ethylene propylene copolymers, ethylene, propylene, norbornene diene copolymers, copolymers of ethylene with unsaturated esters such as vinyl acetate and alkyl acrylates (e.g., ethylene-vinyl acetate, ethylene-ethyl acrylate, etc.), and mixtures thereof.

[0023] Examples of some commercially available polyolefins useful for preparing the grafted polyolefins of the present invention include, for example, NORDEL™ 4725, DOW™ LDPE 310E, VERSIFY™ 2300 (all available from The Dow Chemical Company), and mixtures thereof.

[0024] In a general embodiment, the concentration of component (i), which is a polyolefin of the present invention useful for preparing the grafted polyolefin composition, can be in the range of 90.0 wt% to 99.9 wt%, in another embodiment 95.0 wt% to 99.0 wt%, and in yet another embodiment 97.0 wt% to 99.0 wt%, based on the total weight of all components in the composition.

[0025] Component (ii) of the formulation or composition used to produce the grafted polyolefins of the present invention having improved yellowness characteristics is at least one monomer. For example, as component (ii) which is a monomer, 3-methylfuran-2,5-dione, 3,4-dimethylfuran-2,5-dione, 3-ethylfuran-2,5-dione, 3,4-diethylfuran-2,5-dione, and combinations thereof may be mentioned.

[0026] The concentration of component (ii), which is a monomer useful in the preparation of the grafted polyolefins of the present invention having improved yellowness characteristics, can be in the range of 0.05 wt% to 5.0 wt%, in another embodiment 0.5 wt% to 3.0 wt%, and in yet another embodiment 1.0 wt% to 2.5 wt%, based on the total weight of all components in the composition. Using a concentration above the 5.0 wt% level can make it difficult to graft the polymer, and below the 0.05 wt% level, sufficient grafting of the polymer is not provided.

[0027] Component (iii) of the formulation or composition used to produce the grafted polyolefin of the present invention having improved yellowness characteristics is at least one free radical initiator. Any free radical initiator known to those skilled in the art of grafting can be used in the present invention. For example, as component (iii) which is a free radical initiator, dialkyl peroxides and hydroperoxides, diacyl peroxides, peresters, organic polyoxides, azo compounds, and combinations thereof can be mentioned.

[0028] Examples of some commercially available free radical initiators useful for preparing the grafted polyolefins of the present invention include dicumyl peroxide ("dicumyl peroxide, DCP"), benzoyl peroxide ("benzoyl peroxide, BPO"), azobisisobutyronitrile ("azobisisobutyronitrile, AIBN"), tert-butyl peroxybenzoate, di-tert-amyl peroxide ("di-tert-amyl peroxide, DTAP"), bis(t-butyl-peroxy isopropyl) benzene ("bis (t-butyl-peroxy isopropyl) benzene, BIPB"), isopropylcumyl t-butyl peroxide, t-butylcumyl peroxide, di-t-butyl peroxide, 2,5-bis(t-butylperoxy)-2,5-dimethylhexane, 2,5-bis(t-butylperoxy)-2,5-dimethylhexane-3, 1,1-bis(t-butylperoxy)3,3,5-trimethylcyclohexane, isopropylcumylcumyl peroxide, butyl 4,4-di(tert-butylperoxy)valerate, di(isopropylcumyl)peroxide, 1,1-di-(tert-butylperoxy)cyclohexane (e.g., Luperox® 331), 1,1-di-(tert-amylperoxy)cyclohexane (e.g., Luperox 531®), tert-butyl peroxyacetate ("tert-butyl peroxyacetate, TBPA"), tert-amyl peroxyacetate ("tert-amyl peroxyacetate, TAPA"), 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane (e.g., Luperox® 101), tert-butylperoxy-2-ethylhexyl carbonate ("tert-butylperoxy-2-ethylhexyl carbonate, TBEC"), 3,6,9-triethyl-3,6,9-trimethyl-1,4,7-triperoxonan (e.g., Trigonox® 301), and mixtures thereof.

[0029] In a preferred embodiment, the free radical initiator component (iii) of the composition of the present invention comprises, consists essentially of, or consists of DCP, BPO, and mixtures thereof.

[0030] The concentration of component (iii), which is a free radical initiator useful in the preparation of the grafted polyolefin having the improved yellowness characteristics of the present invention, can be, in a general embodiment, 0.01% to 3.00% by weight, in another embodiment 0.05% to 2.00% by weight, and in yet another embodiment 0.1% to 1.00% by weight, based on the total weight of all components in the composition. Using a concentration exceeding the 3.00% by weight level can result in gelation, and below the 0.1% by weight level, sufficient grafting to the polymer is not provided.

[0031] Optionally, the composition of the present invention may be formulated with a variety of additives to enable the performance of specific functions while maintaining the excellent advantages / characteristics of the composition of the present invention. For example, component (iv), which is an optional additive useful in the composition of the present invention, may be selected from the group consisting of colorants; mineral fillers, process oils; flame retardants, blowing agents; processing aids, antioxidants; and mixtures thereof.

[0032] The optional compound, when used in the preparation of the grafted polyolefin having the improved yellowness characteristics of the present invention, may be present in a general amount of 0% to 10% by weight in one embodiment, 0.01% to 5% by weight in another embodiment, and 0.1% to 1% by weight in yet another embodiment.

[0033] In one broad embodiment, a process for making a grafted polyolefin having improved yellowness characteristics of the present invention comprises reacting a mixture of (i) at least one polyolefin, (ii) at least one monomer, wherein the at least one monomer is selected from the group consisting of 3-methylfuran-2,5-dione, 3,4-dimethylfuran-2,5-dione, or combinations thereof, and (iii) at least one free radical initiator for forming the grafted polyolefin, wherein the grafted polyolefin has a yellowness index YIE313 of less than 30. One or more additional optional components, ingredients, agents, or compounds (iv) may be added to the composition as needed.

[0034] The composition, formulation, or mixture described above is formed by mixing, admixing, or blending (i) at least one polyolefin, (ii) at least one monomer, wherein at least one monomer is selected from the group consisting of 3-methylfuran-2,5-dione, 3,4-dimethylfuran-2,5-dione, or combinations thereof, and (iii) at least one free radical initiator under process conditions for forming a grafted polyolefin, wherein the grafted polyolefin has a yellowness index YIE313 of less than 30. For example, components (i), (ii), (iii), and optionally (iv) can be mixed together at the desired concentrations discussed above to form a reactive mixture, and then the reactive mixture can be heated at a temperature of 140°C to 220°C in one embodiment, 160°C to 220°C in another embodiment, and 180°C to 220°C in yet another embodiment to provide a reaction for forming the grafted polyolefin. Optionally, component (iv), which is an additive as desired, can be mixed with any one or more of components (i), (ii), and (iii). The order of mixing of the components is not important, and after mixing two or more components together, the remaining components can be added. The components of the formulation can be mixed together by any conventional mixing process and apparatus known to those skilled in the art of mixing.

[0035] In other embodiments, the process for making the compositions of the present invention and forming a grafted polyolefin having improved yellowness characteristics comprises: (a) providing the following components: (i) at least one polyolefin; (ii) at least one monomer, wherein at least one monomer is selected from the group consisting of 3-methylfuran-2,5-dione, 3,4-dimethylfuran-2,5-dione, or combinations thereof; (iii) at least one free radical initiator; and (iv) optionally, additives; (b) mixing at least one polyolefin, at least one monomer, at least one free radical initiator, and any optional additives as needed to form a reactive mixture, which can be done using methods and apparatus known to those skilled in the art, such as an extruder, for forming the reactive mixture; and (c) reacting the reactive mixture or allowing the reactive mixture to react by heating the mixture, for example, at a high temperature (e.g., a temperature higher than the melting temperature of the polyolefin), to form a grafted polyolefin having a yellowness index YIE313 of less than 30.

[0036] For example, in step (c) above, the reactive mixture of components (i), (ii), (iii), and optionally (iv) discussed above can be heated at a temperature sufficient to form the grafted polyolefin of the present invention, which is, in one embodiment, from 140 °C to 240 °C, in another embodiment from 160 °C to 240 °C, and in yet another embodiment from 180 °C to 240 °C.

[0037] The resulting grafted polyolefin formed as described above can be further processed by methods well known to those skilled in the art to form shaped or finished parts or articles.

[0038] The grafted polyolefin of the present invention prepared according to the method described above has several advantageous properties and / or benefits. For example, some of the properties / benefits exhibited by the grafted polyolefin of the present invention include, for example, that the grafted polyolefin has a yellowness index YIE313 of less than 30 in a general embodiment.

[0039] In some embodiments, the grafted polyolefin has a yellowness index YIE313 of less than 30 in a general embodiment, less than 15 in another embodiment, and less than 5 in yet another embodiment. In other embodiments, the grafted polyolefin has a yellowness index YIE313 of from 0 to less than 30 in one embodiment, from 10 to less than 30 in another embodiment, and from 20 to less than 30 in yet another embodiment. The yellowness index is measured by the following procedure described in the yellowing index test of the examples, which includes performing a test with a Hunterlab ColorQuest XE (available from Hunterlab) with a 10° observer and a D65 light source in reflection mode using a single-layer film of about 2 mm prepared by the process described in the examples.

[0040] The grafted polyolefin of the present invention can be used, for example, as an adhesive layer, compatibilizer, impact resistance improver, crosslinkable polyolefin, etc. in applications where such materials are useful.

Examples

[0041] The following Inventive Examples (Inv.Ex.) and Comparative Examples (Comp.Ex.) of the present invention (collectively referred to as "Examples") are presented herein to explain the features of the present invention in more detail, but are not intended to be construed as limiting the scope of the claims, either explicitly or implicitly. The Inventive Examples of the present invention are identified by Arabic numerals, and the Comparative Examples are represented by alphabetical characters. In the following experiments, the performance of the embodiments of the compositions described herein is analyzed. Unless otherwise indicated, all parts and percentages are by weight based on the total weight.

[0042] Name Some of the names and abbreviations used for some of the materials and items used in the examples are as follows. "MAH" represents maleic anhydride. "MFD" represents 3-methylfuran-2,5-dione. "DMFD" represents 3,4-dimethylfuran-2,5-dione. "DCP" represents dicumyl peroxide. "MI" represents melt index. "ENB" represents ethylidene norbornene. "FTIR" represents Fourier transform infrared. "ATR" represents attenuated total reflectance. "TD" represents thermal desorption. "Py" represents pyrolysis. "EGA" represents evolved gas analysis. "GC" represents gas chromatography. "MS" represents mass spectrometry. "EI" represents electron impact, one mode of ionization. "PFTBA" represents perfluorotributylamine, a chemical used to calibrate a mass spectrometer. "CIELAB color space" or "L * a * b *" is a well-known color space defined by the International Commission on Illumination (abbreviated as CIE). "L * a * b * " represents color as three values, where "L * " represents perceived lightness, and "a * " and "b * " represent four unique colors of human vision, namely red, green, blue, and yellow. This is useful in the industry for detecting small differences in color.

[0043] Raw materials The appropriate raw materials (components) used in the examples are listed in Table I.

[0044]

Table 1

[0045] Formulation General process for preparing grafted polyolefin The components / formulations used to produce the grafted polyolefin in the examples are listed in Table II. Components (i) - (iii), and optionally (iv), were mixed using a Brabender mixer with the following general process steps. (1) The polymer (e.g., Polymer 1, Polymer 2, or Polymer 3) was fed into a Brabender mixer set at a temperature of 120°C with a rotor speed of 10 rpm. (2) The peroxide (e.g., Peroxide 1) and the anhydride (e.g., Anhydride 1, Anhydride 2, or Anhydride 3) were fed into the polymer melt in the mixer at the set temperature to form a reactive mixture. (3) The resulting mixture of components was subjected to a final mixing for 10 minutes at a temperature of 180°C and a rotor speed of 45 rpm. (4) The compound obtained from the mixer was collected for analysis.

[0046]

Table 2

[0047] Analysis and test methods FTIR test Samples of the grafted polyolefin polymer were investigated by Fourier Transform Infrared (FTIR) spectroscopy using a single reflection attenuated total reflectance (ATR) attachment equipped with a diamond crystal. The penetration depth during ATR analysis was estimated to be 2 μm. Spectra were collected at a resolution of 4 cm-1 with 32 scans using a Thermo Electron Nicolet 5700 Optical Bench (available from Thermo Electron). The success of the grafting of the sample was demonstrated using FTIR analysis.

[0048] Yellowing index test The method used to measure the yellowing index of the film sample (referred to herein as the "yellowing index test" or "YI test") was performed as follows. A single-layer film sample was prepared by hot pressing approximately 20 g of the grafted polyolefin polymer with a hot press to obtain a single-layer film of approximately 2 mm as follows. 1. A mold having dimensions of 100 mm × 100 mm × 2 mm was used. 2. Approximately 20 g of pellets / bulk was weighed and placed in the mold. 3. The mold was sandwiched between the upper and lower plates of the hot press at 0 MPa and preheated at 120 °C for 10 minutes. 4. The mold was held at 120 °C and 5 MPa for 0.5 minutes. 5. The mold was held at 120 °C and 10 MPa for 0.5 minutes. 6. After venting 8 times (to degas the air that may be present in the resin), the mold was held at 180 °C and 10 MPa for approximately 13 minutes. 7. The mold was cooled from 180 °C to 60 °C within 10 minutes at 10 MPa. 8. The single-layer film formed in the mold was removed from the mold for testing.

[0049] The obtained single-layer film was subjected to the YI test. The yellowness index test using the YI test of the single-layer film prepared as described above was carried out with a Hunterlab ColorQuest XE (available from Hunterlab) having a light source of D65 with an observer of 10° and a reflection model. The values obtained for the measurement of the yellowness index (YIE313) using the YI test are described in Table III. It should be noted that the YIE313 number depends on the sample preparation. The procedure of ASTM D1925 is the standard for the method of testing for the YIE313 number, but the procedure of ASTM D1925 does not include the preparation of the test piece to be tested for yellowness. The YIE313 number is comparable only between samples prepared using the same sample preparation procedure.

[0050]

Table 3

[0051] Discussion of Results The results described in the table above show that the grafted polyolefins of the examples of the present invention have much better color performance than the grafted polyolefins of the comparative examples. For example, the polyolefins used in Examples 1 and 4 of the present invention are the same as the polyolefin used in Comparative Example A. When the grafted polyolefins of Examples 1 and 4 of the present invention are compared with the grafted polyolefin of Comparative Example A, the grafted polyolefins of Examples 1 and 4 of the present invention show much better color (less yellowing) than the grafted polyolefin of Comparative Example A, and the polyolefin grafted in Comparative Example A is grafted with MAH.

[0052] In another embodiment, the polyolefins used in Examples 2 and 5 of the present invention are the same as the polyolefins used in Comparative Example B. When the grafted polyolefins of Examples 2 and 5 of the present invention are compared with the grafted polyolefin of Comparative Example B, the grafted polyolefins of Examples 2 and 5 of the present invention exhibit a much better color (less yellowing) than the grafted polyolefin of Comparative Example B. The polyolefin grafted in Comparative Example B is grafted with MAH.

[0053] In yet another embodiment, the polyolefins used in Examples 3 and 6 of the present invention are the same as the polyolefins used in Comparative Example C. When the grafted polyolefins of Examples 3 and 6 of the present invention are compared with the grafted polyolefin of Comparative Example C, the grafted polyolefins of Examples 3 and 6 of the present invention exhibit a much better color (less yellowing) than the grafted polyolefin of Comparative Example C. The polyolefin grafted in Comparative Example C is grafted with MAH.

Claims

1. A process for producing a grafted polyolefin having improved yellowness characteristics, the process comprising reacting a mixture of: (i) at least one polyolefin; (ii) at least one monomer, wherein the at least one monomer is selected from one or more acid compounds having the following general chemical formula (I), or 【Chemical 1】 the at least one monomer is selected from one or more hydrolyzable acid compounds having the following general chemical formula (II), 【Chemical 2】 wherein in formula (I) and formula (II), with the condition that neither R1 nor R2 is H, either R1 or R2 is H, and at least one of R1 and R2 is an alkyl or alkenyl having 1 to 20 carbon atoms, and R1, R2, or both R1 and R2 may further contain an ester, a heteroatom, an aromatic compound, or a halogen; at least one monomer; (iii) at least one free radical initiator for forming the grafted polyolefin, wherein the grafted polyolefin has a yellowness index YIE313 of less than 30 when determined according to the YI test. A process for producing a grafted polyolefin having improved yellowness characteristics.

2. The process according to claim 1, wherein the grafted polyolefin has a yellowness index YIE313 of 0 to less than 30 when determined according to the YI test.

3. The process according to claim 1, wherein the grafted polyolefin grafted with the monomer of component (ii) has an improved yellowness index YIE313 of at least 30 percent to 70 percent compared to a grafted polyolefin grafted with maleic anhydride when determined according to the YI test.

4. The process according to claim 1, wherein the at least one monomer is selected from the group consisting of 3-methylfuran-2,5-dione, 3,4-dimethylfuran-2,5-dione, or combinations thereof.

5. The process according to claim 1, wherein the at least one polyolefin is polyethylene, an ethylene alpha-olefin copolymer, an ethylene alpha-olefin diene terpolymer, and mixtures thereof.

6. The at least one free radical initiator is selected from the group consisting of dicumyl peroxide, bis(t-butyl-peroxyisopropyl)benzene, t-butylcumyl peroxide, di-t-butyl peroxide, 2,5-bis(t-butylperoxy)-2,5-dimethylhexane, 2,5-bis(t-butylperoxy)-2,5-dimethylhex-3-yne, and 3,6,9-triethyl-3,6,9-trimethyl-1,4,7-triperoxonan; a process according to claim 1.

7. The concentration of the at least one polyolefin is from 95.0 wt% to 99.9 wt%, the concentration of the at least one monomer is from 0.1 wt% to 5.0 wt%, and the concentration of the at least one free radical initiator is from 0.01 wt% to 3.0 wt%; a process according to claim 1.

8. The process is carried out at a temperature higher than the melting point of the polyolefin; a process according to claim 1.

9. The process is carried out at a temperature of 50°C to 350°C; a process according to claim 1.

10. The process is carried out in a continuous process using an extruder or in a batch process using a mixing vessel; a process according to claim 1.

11. The process according to any one of claims 1 to 10 further comprising the step of forming the grafted polyolefin into a molded product or article.

12. A product or article formed from the process according to any one of claims 1 to 10.

13. The product or article is a film, pellet, or granule; a product or article according to claim 12.

14. A composition for producing a grafted polyolefin having improved yellowness characteristics, the composition comprising (i) at least one polyolefin, and (ii) at least one monomer, wherein the at least one monomer is selected from one or more acid compounds having the following general chemical formula (I), or 【Chemical Formula 3】 the at least one monomer is selected from one or more hydrolyzable acid compounds having the following general chemical formula (II). 【Chemical Formula 4】 In formulas (I) and (II), provided that R1 and R2 are not both H, either R1 or R2 is H, and at least one of R1 and R2 is alkyl or alkenyl having 1 to 20 carbon atoms, and R1, R2, or both R1 and R2 may further contain an ester, a heteroatom, an aromatic compound, or a halogen, and at least one monomer, (iii) at least one free radical initiator for forming a grafted polyolefin, wherein the grafted polyolefin has a yellowness index YIE313 of less than 30, a composition for producing a grafted polyolefin having improved yellowness characteristics, comprising a reaction mixture of at least one free radical initiator.

15. The composition according to claim 14, wherein the grafted polyolefin grafted with the monomer of component (ii) has an improved yellowness index YIE313 of at least 30 percent to 70 percent compared to a grafted polyolefin grafted with maleic anhydride when determined according to the YI test.

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