Hot melt adhesive composition

Abstract

The present invention relates to a hot melt adhesive composition comprising: i) a first metallocene catalyzed propylene-based copolymer; ii) a second metallocene catalyzed propylene-based copolymer; iii) a polyolefin copolymer selected from the group consisting of iii-1) an acid grafted polyolefin copolymer; iii-2) copolymers based on olefins and unsaturated monomers containing acid or anhydride groups; and iii-3) mixtures thereof; iv) a tackifier; and v) an optional third metallocene catalyzed propylene-based copolymer; wherein each of the metallocene catalyzed propylene-based copolymers i) and ii) independently of each other comprises from 1 wt. % to 20 wt. % ethylene units.

Description

[Technical field]

[0001] The present invention relates to a hot melt adhesive composition and its use for bonding nonwoven materials. [Background technology]

[0002] Hot melt adhesives (HM adhesives) are substances that are solid at room temperature and often contain neither water nor solvents. They are applied in the molten state, generally after heating to temperatures between 100 and 250° C., most often between 130 and 180° C., and solidify during cooling, thus forming a seal (or adhesive bond), thereby ensuring the adhesion of the two substrates to be assembled. Hot melt adhesives are generally provided in the form of a composition comprising a thermoplastic polymer and, optionally, a tackifying resin and a plasticizer.

[0003] Hot melt adhesives have good stability and do not require the use of solvents, and are therefore widely used in a variety of applications, such as packaging, bookbinding, and woodworking. Such adhesives can also be used in nonwoven applications. For example, disposable nonwoven absorbent articles are widely used in baby, infant, incontinent adult, and feminine care applications.

[0004] Typical disposable nonwoven absorbent articles include disposable diapers, training pants, adult incontinence pads and briefs, feminine sanitary napkins or pads, surgical masks, etc. These items are intended to receive and contain bodily fluids and are typically worn against or in close proximity to the skin.

[0005] To manufacture disposable nonwoven absorbent articles, hot melt adhesive compositions are commonly used to bond together the various substrates of said articles because they provide rapid bonding compared to other adhesives, such as water- or solvent-based adhesive compositions, which require a water or solvent drying step.

[0006] When hot melt adhesives are used in the field of hygiene products, the nature of their application means that they often come into contact with moisture, such as body fluids. It is well known that some hot melt adhesives have poor adhesion in a wet state. If the hot melt adhesive is used in an area where it is likely to come into contact with moisture, the adhesion between the substrates involved cannot be maintained and the product itself may disintegrate. For this reason, it is desirable for the adhesive properties of the hot melt adhesive to be maintained in its wet state (wet adhesion). By "wet adhesion" is meant the ability to attach strongly to a substrate material in the presence of moist environmental conditions. To enhance the wet adhesion of the hot melt composition, acid modified waxes may be added. However, such compounds tend to produce unpleasant odors and dark colored adhesives, which can lead to product quality degradation.

[0007] There remains a need for hot melt adhesive compositions that provide good adhesion, especially high wet bond strength, especially in nonwoven material based products, and even more specifically in hydrophilic nonwoven material based products. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] A. Hot Melt Adhesive Composition The present invention relates to: i) a first metallocene-catalyzed propylene-based copolymer; ii) a second metallocene-catalyzed propylene-based copolymer; iii) iii-1) acid-grafted polyolefin copolymers; iii-2) copolymers based on olefins and unsaturated monomers containing acid or anhydride groups; and iii-3) Mixtures of these A polyolefin copolymer selected from the group consisting of: iv) tackifiers; v) an optional third metallocene-catalyzed propylene-based copolymer; 1. A hot melt adhesive composition comprising: The present invention relates to a hot melt adhesive composition, wherein each of the metallocene-catalyzed propylene-based copolymers i) and ii) independently of the other comprises from 1 wt. % to 20 wt. % of ethylene units.

[0009] As used herein, "propylene-based copolymer" means a copolymer that contains greater than 50% by weight of propylene monomer units, based on the weight of the copolymer.

[0010] As used herein, "acid-grafted polyolefin copolymer" means a polyolefin copolymer grafted with a carboxylic acid, a carboxylic acid anhydride, a carboxylic acid ester, or mixtures thereof.

[0011] As used herein, the term "copolymer" refers to a polymer formed by the polymerization of at least two different monomers. This includes both copolymers (two different monomers) and terpolymers (three or more different monomers).

[0012] As used herein, the term "metallocene-catalyzed copolymer" refers to a copolymer obtained through the polymerization of monomers in the presence of a metallocene catalyst system. Metallocene catalyst systems are well known. They typically include a transition metal center and one or two ligands coordinated to the metal center. Examples of such systems are disclosed in US 9,998,469.

[0013] The hot melt adhesive composition comprises at least four different components i), ii), iii), iv) and, when including the optional component v), at least five different components.

[0014] Copolymers i), ii) and v) are herein not acid-modified copolymers and are preferably not functionalized.

[0015] In the present invention, "acid-modified copolymer" means a copolymer that has been chemically modified with a carboxylic acid, a carboxylic anhydride, a carboxylic ester, or a mixture thereof. The acid-modified copolymer may be, for example, a copolymer grafted with a carboxylic acid, a carboxylic anhydride, a carboxylic ester, or a mixture thereof.

[0016] According to the present invention, the metallocene-catalyzed propylene-based copolymers i), ii) and v) are not waxes, in particular they are not polyolefin waxes. The same applies to the polyolefin copolymer iii).

[0017] First metallocene-catalyzed propylene-based copolymer i) The first metallocene-catalyzed propylene-based copolymer i) may comprise more than 60% by weight, preferably more than 70% by weight, even more preferably more than 80% by weight and advantageously more than 85% by weight of propylene units relative to the weight of said copolymer.

[0018] The first metallocene-catalyzed propylene-based copolymer i) comprises from 1 wt. % to 20 wt. %, preferably from 1 wt. % to 15 wt. %, even more preferably from 2 wt. % to 10 wt. % of ethylene units relative to the weight of said copolymer.

[0019] The first metallocene-catalyzed propylene-based copolymer i) may contain, in addition to propylene and ethylene, an olefin comonomer, which may be selected from 1-butene, 1-pentene, 3-methyl-1-butene, 3-methyl-1-pentene, 1-hexene, 1-dodecene, 1-octene, 1-decene, and mixtures thereof.

[0020] In a preferred embodiment, the first metallocene-catalyzed propylene-based copolymer i) contains only propylene and ethylene units.

[0021] The first metallocene-catalyzed propylene-based copolymer i) may have a melting point of from 30° C. to 120° C., preferably from 50° C. to 110° C., and even more preferably from 80° C. to 100° C. The melting point can be measured using differential scanning calorimetry (DSC).

[0022] The first metallocene-catalyzed propylene-based copolymer i) may have a glass transition temperature of −75° C. to −10° C., preferably −50° C. to −15° C., and even more preferably −35° C. to −20° C. The glass transition temperature can be measured using differential scanning calorimetry (DSC) according to standard ASTM D3418-82.

[0023] The first metallocene-catalyzed propylene-based copolymer i) has a molecular weight of 0.800 to 0.900 g / cm 3 , preferably 0.850 to 0.890 g / cm 3 , and even more preferably 0.860 to 0.880 g / cm 3 The density is measured according to standard ASTM D-792-00.

[0024] The viscosity of the first metallocene-catalyzed propylene-based copolymer i) at 190° C. may range from 700 mPas to 10000 mPas, preferably from 1000 to 10000 mPas, and even more preferably from 2000 to 9000 mPas. The viscosity may be measured according to ASTM D3236.

[0025] The first metallocene-catalyzed propylene-based interpolymer may have a weight average molecular weight (Mw) ranging from 10,000 g / mol to 80,000 g / mol, preferably from 10,000 g / mol to 50,000 g / mol, and even more preferably from 15,000 g / mol to 40,000 g / mol.

[0026] The weight average molecular weight (Mw) can be measured by gel permeation chromatography (GPC).

[0027] The first metallocene-catalyzed propylene-based interpolymer i) may have an enthalpy of fusion greater than 20 J / g, preferably greater than 30 J / g, and even more preferably greater than 35 J / g, as determined by DSC.

[0028] The terms "enthalpy of fusion", "enthalpy of fusion", "heat of fusion" and "heat of fusion" are used interchangeably.

[0029] The hot melt adhesive composition may comprise from 2% to 50% by weight, preferably from 5% to 30% by weight, even more preferably from 8% to 20% by weight of said copolymer i), relative to the total weight of the hot melt adhesive composition.

[0030] Examples of first copolymers i) useful in the present invention are available from ExxonMobil Chemical Co. under the trade name VistamaXX (eg, Vistamaxx® 8880, etc.).

[0031] Second metallocene-catalyzed propylene-based copolymer ii) The second metallocene-catalyzed propylene-based copolymer is different from copolymer i) above.

[0032] The second metallocene-catalyzed propylene-based copolymer ii) may comprise more than 60% by weight, preferably more than 70% by weight, even more preferably more than 80% by weight and advantageously more than 85% by weight of propylene units relative to the weight of said copolymer.

[0033] The second metallocene-catalyzed propylene-based copolymer ii) comprises from 1 wt.% to 20 wt.%, preferably from 5 wt.% to 15 wt.%, even more preferably from 8 wt.% to 15 wt.% of ethylene units based on the weight of said copolymer.

[0034] The second metallocene-catalyzed propylene-based copolymer ii) may contain, in addition to propylene and ethylene, an olefin comonomer, which may be selected from 1-butene, 1-pentene, 3-methyl-1-butene, 3-methyl-1-pentene, 1-hexene, 1-dodecene, 1-octene, 1-decene, and mixtures thereof.

[0035] In a preferred embodiment, the second metallocene-catalyzed propylene-based copolymer ii) contains only propylene and ethylene units.

[0036] The second metallocene-catalyzed propylene-based copolymer ii) may have a melting point of from 30° C. to 120° C., preferably from 50° C. to 110° C., and even more preferably from 80° C. to 100° C. The melting point can be measured using differential scanning calorimetry (DSC).

[0037] The second metallocene-catalyzed propylene-based copolymer ii) may have a glass transition temperature of −75° C. to −10° C., preferably −50° C. to −15° C., and even more preferably −35° C. to −20° C. The glass transition temperature can be measured using differential scanning calorimetry (DSC) according to standard ASTM D3418-82.

[0038] The second metallocene-catalyzed propylene-based copolymer ii) has a viscosity of 0.800 to 0.900 g / cm 3 , preferably 0.850 to 0.890 g / cm 3 , and even more preferably 0.860 to 0.880 g / cm 3 The density is measured according to standard ASTM D-792-00.

[0039] The viscosity of the second metallocene-catalyzed propylene-based copolymer ii) at 190° C. may range from 700 mPas to 20000 mPas, preferably from 800 to 10000 mPas, and even more preferably from 1000 to 9000 mPas. The viscosity may be measured according to ASTM D3236.

[0040] The second metallocene-catalyzed propylene-based copolymer ii) may have an enthalpy of fusion of greater than 5 J / g, preferably from 5 J / g to 20 J / g, more preferably from 5 J / g to 10 J / g, as determined by DSC.

[0041] The second metallocene-catalyzed propylene-based copolymer ii) may have a weight average molecular weight (Mw) ranging from 10000 g / mol to 80000 g / mol, preferably from 10000 g / mol to 50000 g / mol, even more preferably from 20000 g / mol to 50000 g / mol.

[0042] The hot melt adhesive composition may comprise from 1% to 50% by weight, preferably from 2% to 40% by weight, even more preferably from 2% to 35% by weight of said copolymer ii), relative to the total weight of the hot melt adhesive composition.

[0043] Examples of second copolymers ii) useful in the present invention are available from ExxonMobil Chemical Co. under the trade name VistamaXX (eg, Vistamaxx® 8380, etc.).

[0044] Polyolefin copolymers iii) The hot melt adhesive composition comprises: iii-1) acid-grafted polyolefin copolymers; iii-2) copolymers based on olefins and unsaturated monomers containing acid or anhydride groups; and iii-3) Mixtures of these The polyolefin copolymer iii) is selected from the group consisting of:

[0045] Acid-grafted polyolefin copolymer III-1) In the present invention, "acid-grafted copolymer" means a copolymer grafted with a carboxylic acid, a carboxylic anhydride, a carboxylic ester or a mixture thereof. Grafting can be carried out by methods known to those skilled in the art, for example, grafting can be carried out by reactive extrusion. Grafting can be carried out in the presence of a radical initiator such as an organic peroxide, an azo compound, etc.

[0046] The acid-grafted polyolefin copolymer iii-1) is preferably a polymer of at least two alpha-olefins.

[0047] The alpha olefin may be selected from the group consisting of ethylene, propylene, 1-butene, pentene, hexene, heptene, octene, nonene, decene, undecene, dodene, and mixtures thereof.

[0048] Preferably, the alpha olefin is selected from the group consisting of ethylene, propylene, 1-butene, and mixtures thereof.

[0049] More preferably, the polyolefin is either a copolymer of ethylene and propylene or a terpolymer of ethylene, propylene and 1-butene. Preferably, the copolymer of ethylene and propylene comprises more than 50% by weight of propylene units relative to the total weight of said copolymer. Preferably, the terpolymer of ethylene, propylene and 1-butene is 1-butene rich. By "1-butene rich terpolymer" is meant a terpolymer in which the main unit is 1-butene.

[0050] The carboxylic acid may be selected from dicarboxylic acids, such as maleic acid, fumaric acid, succinic acid, phthalic acid, glutaric acid, itaconic acid, acrylic acid, methacrylic acid, and mixtures thereof. The carboxylic acid ester may be derived from the esters of the above carboxylic acids.

[0051] The carboxylic acid anhydride may be selected from the group consisting of maleic anhydride, succinic anhydride, phthalic anhydride, glutaric anhydride, and mixtures thereof.

[0052] Preferably, the acid grafted polyolefin copolymer iii-1) is a maleic anhydride grafted polyolefin copolymer.

[0053] The acid functional group content of the acid grafted polyolefin copolymer iii-1) may range from 0.01% to 5% by weight, preferably from 0.1% to 2% by weight, even more preferably from 0.5% to 1.5% by weight, based on the total weight of the acid grafted polyolefin copolymer.

[0054] The acid grafted polyolefin copolymer iii-1) may have a softening point of 50° C. to 180° C., preferably 80° C. to 150° C., even more preferably 100° C. to 140° C. The softening point can be measured according to the ASTM E-28 standard.

[0055] The acid-grafted polyolefin copolymer III-1) has a viscosity of 0.85 to 0.90 g / cm 3 , preferably 0.86 to 0.89 g / cm 3 , and even more preferably from 0.865 to 0.88 g / cm 3 The density is measured according to standard ASTM D-792-00.

[0056] The acid grafted polyolefin copolymer iii-1) preferably has a viscosity of 0.86 to 0.89 g / cm 3 , and even more preferably from 0.865 to 0.88 g / cm 3 has a density of

[0057] The acid grafted polyolefin copolymer iii-1) may have a weight average molecular weight (Mw) ranging from 10000 g / mol to 100000 g / mol, preferably from 20000 g / mol to 80000 g / mol, even more preferably from 30000 g / mol to 70000 g / mol.

[0058] The acid grafted polyolefin copolymer iii-1) preferably has a weight average molecular weight (Mw) in the range of 20000 g / mol to 80000 g / mol, even more preferably 30000 g / mol to 70000 g / mol.

[0059] The acid-grafted polyolefin copolymer preferably has a viscosity of 2000 mPas or more, more preferably 4000 mPa.s or more, and even more preferably 6000 mPas or more at 190° C. Viscosity may be measured according to ASTM D3236.

[0060] The hot melt adhesive composition may comprise from 0.05% to 50% by weight, preferably from 1% to 40% by weight, even more preferably from 2% to 35% by weight of copolymer iii-1), relative to the total weight of the hot melt adhesive composition.

[0061] Preferably, the acid-grafted polyolefin copolymer iii-1) is a low crystallinity APAO amorphous polyalphaolefin.

[0062] Preferably, the acid-grafted polyolefin copolymer iii-1) has a needle penetration of 10 dmm or more, more preferably 13 dmm or more. The needle penetration is measured according to DIN EN 1426.

[0063] As used herein, the term "dmm" means decimeters.

[0064] Examples of acid-grafted polyolefin copolymers iii-1) useful in the present invention are available from Evonik under the trade name Vestoplast (eg, Vestoplast® 308, etc.) or from EASTMAN under the trade name Eastoflex.

[0065] Copolymers based on olefins and unsaturated monomers containing acid or anhydride groups iii-2) The copolymers iii-2) are produced from the copolymerization of at least one olefin, one unsaturated monomer containing an acid or an anhydride group, and optionally additional monomers.

[0066] The olefin may be selected from the group consisting of ethylene, propylene, 1-butene, pentene, hexene, heptene, octene, nonene, decene, undecene, dodene, and mixtures thereof; preferably ethylene or propylene, even more preferably ethylene.

[0067] The unsaturated monomers containing acid or anhydride groups may be selected from unsaturated monocarboxylic acids, unsaturated dicarboxylic acids, anhydrides of the aforementioned acids, and mixtures thereof.

[0068] The unsaturated monocarboxylic acid may be (meth)acrylic acid, crotonic acid, itaconic acid, citraconic acid, and the unsaturated dicarboxylic acid may be maleic acid, fumaric acid, or a semi-ester of maleic acid / fumaric acid with a C1-C5 alkanol.

[0069] The unsaturated monomer containing an acid or anhydride group is preferably maleic acid or maleic anhydride, even more preferably maleic anhydride.

[0070] The optional additional monomer may be selected from (meth)acrylic acid esters. The (meth)acrylic acid esters may be selected from esters with low molecular weight C1-C8 alkanols, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, or 2-ethylhexyl (meth)acrylate. Preferably, the (meth)acrylic acid ester is ethyl acrylate.

[0071] The copolymer iii-2) preferably comprises more than 50% by weight, more preferably more than 60% by weight, even more preferably more than 70% by weight of olefin units relative to the total weight of said copolymer iii-2).

[0072] Copolymer iii-2) preferably comprises less than 10% by weight, more preferably less than 5% by weight, of unsaturated monomers containing acid or anhydride groups, relative to the total weight of said copolymer iii-2).

[0073] Preferably, the copolymer iii-2) is an ethylene-ethyl acrylate-maleic anhydride copolymer.

[0074] Examples of copolymers iii-2) useful in the present invention are available from Arkema under the trade names Lotader® 8200 (ethylene-ethyl acrylate-maleic anhydride copolymer), Lotader® 5500 and Lotader® 6600.

[0075] Optional third metallocene-catalyzed propylene-based copolymer v) The hot melt adhesive composition may include a third metallocene-catalyzed propylene-based copolymer v).

[0076] The third metallocene-catalyzed propylene-based copolymer v) is different from each of the copolymers i) and ii) above.

[0077] The third metallocene-catalyzed propylene-based copolymer v) may comprise more than 60% by weight, preferably more than 70% by weight, even more preferably more than 80% by weight and advantageously more than 85% by weight of propylene units relative to the weight of the copolymer.

[0078] The third metallocene-catalyzed propylene-based copolymer v) may contain from 1 wt.% to 20 wt.%, preferably from 5 wt.% to 15 wt.%, even more preferably from 8 wt.% to 15 wt.% of ethylene units based on the weight of said copolymer.

[0079] The third metallocene-catalyzed propylene-based copolymer v) may contain, in addition to propylene and ethylene, an olefin comonomer, which may be selected from 1-butene, 1-pentene, 3-methyl-1-butene, 3-methyl-1-pentene, 1-hexene, 1-dodecene, 1-octene, 1-decene, and mixtures thereof.

[0080] In a preferred embodiment, the third metallocene-catalyzed propylene-based copolymer v) contains only propylene and ethylene units.

[0081] The third metallocene-catalyzed propylene-based copolymer v) may have a melting point of from 30° C. to 120° C., preferably from 50° C. to 110° C., and even more preferably from 80° C. to 100° C. The melting point can be measured using differential scanning calorimetry (DSC).

[0082] The third metallocene-catalyzed propylene-based copolymer v) has a viscosity of 0.800 to 0.900 g / cm 3 , preferably 0.850 to 0.890 g / cm 3 , and even more preferably 0.860 to 0.880 g / cm 3 The density is measured according to standard ASTM D-792-00.

[0083] The third metallocene-catalyzed propylene-based copolymer v) may have a melt flow rate ranging from 3 g / min to 100 g / min, preferably from 8 g / min to 80 g / min, more preferably from 10 g / min to 60 g / min, the melt flow rate being measured at 190° C. / 2.16 kg according to ASTM D1238.

[0084] The third metallocene-catalyzed propylene-based copolymer v) may have a weight average molecular weight (Mw) of more than 50000 g / mol, preferably more than 80000 g / mol, even more preferably from 100000 g / mol to 200000 g / mol.

[0085] The third metallocene-catalyzed propylene-based copolymer v) may have an enthalpy of fusion of greater than 5 J / g, preferably from 5 J / g to 20 J / g, more preferably from 5 J / g to 10 J / g, as determined by DSC.

[0086] The hot melt adhesive composition may comprise from 0 to 20% by weight, preferably from 0 to 10% by weight, even more preferably from 0 to 5% by weight of said copolymer v), relative to the total weight of the hot melt adhesive composition.

[0087] An example of a second copolymer v) useful in the present invention is available from ExxonMobil Chemical Co. under the trade name VistamaXX (eg, Vistamaxx® 6502, etc.).

[0088] composition The hot melt adhesive composition comprises a tackifying resin, which may be present in the hot melt adhesive composition in a content of from 20 to 70% by weight, preferably from 25 to 60% by weight, even more preferably from 30 to 50% by weight, relative to the total weight of the hot melt adhesive composition.

[0089] The tackifying resin or tackifier used in the hot melt adhesive of the present invention is compatible with the polymer. As used herein, the term "tackifying resin" or "tackifier" refers to: (a) aliphatic and cycloaliphatic petroleum hydrocarbon resins having a Ring and Ball softening point of 90°C to 160°C as determined by ASTM method E28-58T, the latter resins being produced by polymerization of monomers consisting mainly of aliphatic and / or cycloaliphatic olefins and diolefins; also including hydrogenated aliphatic and cycloaliphatic petroleum hydrocarbon resins, examples of such commercially available resins based on the C5 olefin fraction of this type being Piccotac 95 tackifying resin sold by Hercules Corp. and Escorez 1310LC sold by ExxonMobil Chemical Company, or even C115W manufactured by Nanjing Yangzi Eastman Chemical; (b) aromatic petroleum hydrocarbon resins and their hydrogenated derivatives; (c) aliphatic / aromatic petroleum-derived hydrocarbon resins and their hydrogenated derivatives; (d) aromatic modified cycloaliphatic resins and their hydrogenated derivatives; (e) polyterpene resins having a softening point of from 95° C. to 140° C., the latter being generally produced from the polymerization of terpene hydrocarbons, such as the monoterpene known as pinene, in the presence of a Friedel-Crafts catalyst at moderately low temperatures; hydrogenated polyterpene resins are also included; (f) Natural terpenes, such as styrene / terpene, α-methylstyrene / terpene and vinyltoluene / terpene copolymers and terpolymers; (g) natural and modified rosins such as, for example, gun rosin, wood rosin, tall oil rosin, distilled rosin, hydrogenated rosin, dimerized rosin, and polymerized rosin; (h) glycerol and pentaerythritol esters of natural and modified rosins, such as, for example, glycerol ester of pale wood rosin, glycerol ester of hydrogenated rosin, glycerol ester of polymerized rosin, pentaerythritol ester of pale wood rosin, pentaerythritol ester of hydrogenated rosin, pentaerythritol ester of tall oil rosin, and phenolic modified pentaerythritol esters of rosin; (i) phenol-modified terpene resins, such as, for example, resin products produced from the condensation of terpenes and phenols in an acidic medium; (j) Mixtures of these Examples include:

[0090] The tackifying resin may have a Ring and Ball softening point (measured by ASTM E28) of at least 90°C, preferably from 100°C to 130°C.

[0091] Preferably, the tackifier is selected from hydrogenated resins.

[0092] Preferably, the tackifier is: (a) aliphatic and cycloaliphatic petroleum hydrocarbon resins having a Ring and Ball softening point of from 90° C. to 160° C. as determined by ASTM method E28-58T, the latter resins being produced by polymerization of monomers consisting primarily of aliphatic and / or cycloaliphatic olefins and diolefins; also including hydrogenated aliphatic and cycloaliphatic petroleum hydrocarbon resins, examples of such commercially available resins based on the C5 olefin fraction of this type being Piccotac 95 tackifying resin sold by Hercules Corp. and Escorez 1310LC sold by ExxonMobil Chemical Company; (b) aromatic petroleum hydrocarbon resins and their hydrogenated derivatives; (c) Aliphatic / aromatic petroleum-derived hydrocarbon resins and their hydrogenated derivatives is selected from the group consisting of:

[0093] In a preferred embodiment, the tackifier is selected from a) aliphatic and cycloaliphatic petroleum hydrocarbon resins having a Ring and Ball softening point of from 90° C. to 160° C., and hydrogenated derivatives thereof.

[0094] In a preferred embodiment, the tackifier is not an acid-modified tackifier.

[0095] In a preferred embodiment, the hot melt adhesive composition does not include an acid-modified tackifier.

[0096] "Acid-modified tackifier" means a tackifier modified with a carboxylic acid, a carboxylic acid anhydride, a carboxylic acid ester, or a mixture thereof. An example of an acid-modified tackifier is a tackifier modified with maleic acid or maleic anhydride.

[0097] The hot melt adhesive composition may include one or more additional ingredients, which may be selected from the group consisting of plasticizers, waxes, stabilizers, inert colorants, fillers, surfactants, other types of polymers, crosslinkers, nucleating agents, reactive compounds, inorganic or organic flame retardants, ultraviolet (UV) or infrared (IR) absorbing agents, UV or IR fluorescent agents, and mixtures thereof.

[0098] Typical fillers include talc, calcium carbonate, clay, silica, mica, wollastonite, feldspar, aluminum silicate, alumina, alumina hydrate, glass microspheres, ceramic microspheres, thermoplastic microspheres, barite, and wood flour.

[0099] A plasticizer is preferably present in the hot melt adhesive composition. More specifically, a solid or liquid plasticizer can be present in the composition of the present invention.

[0100] The plasticizer may be present in the hot melt adhesive composition in a content ranging from 5% to 25% by weight, preferably from 10% to 23% by weight relative to the weight of the hot melt adhesive composition.

[0101] Suitable plasticizers may be selected from naphthenic oils, paraffinic oils, polyisobutylene, benzoic acid esters, and mixtures thereof.

[0102] Naphthenic oils and paraffinic oils are petroleum oils that are mixtures of naphthenic hydrocarbons (aliphatic, saturated or unsaturated C4-C7 membered 30 hydrocarbon rings, preferably aliphatic, saturated or unsaturated C4-C6 membered rings. Examples include cycloalkanes such as cyclopentane, cyclohexane, cycloheptane), paraffinic hydrocarbons (saturated linear or branched alkanes) and aromatic hydrocarbons (aromatic hydrocarbon rings that may be monocyclic or polycyclic, preferably aromatic C6 membered hydrocarbon rings).

[0103] The classification of naphthenic and paraffinic oils is based on the amount of each type of hydrocarbon in the oil. Typically, paraffinic oils have a paraffinic hydrocarbon content of at least 50% by weight, relative to the total weight of the plasticizer; naphthenic oils have a naphthenic hydrocarbon content of 30% to 40% by weight.

[0104] Useful plasticizers are commercially available, examples of which include naphthenic oils sold by NYNAS under the trade names NYFLEX® 223 and NYFLEX® 222B.

[0105] Other plasticizers, such as: - Polyisobutylene such as INDOPOL H300, a liquid polybutene available from INEOS, an oligomer with a molecular weight (Mn) of 1300; - A solid plasticizer such as a benzoate ester, such as 1,4-cyclohexanedimethanol dibenzoate (softening point 118°C), available from EASTMAN CHEMICAL under the name BENZOFLEX 352. etc. may be added to the hot melt adhesive composition according to the present invention.

[0106] The composition according to the invention may contain at least one stabilizer. The stabilizer may be present in the hot melt adhesive composition in a content of 0.1 to 5% by weight, preferably 0.5 to 3% by weight, based on the weight of the hot melt adhesive composition. The incorporation of a useful stabilizer in the hot melt adhesive composition of the invention helps to protect the polymer and thereby the entire adhesive system from the effects of thermal and oxidative degradation reactions that commonly occur during the manufacture and application of the adhesive, as well as during normal exposure of the final product to the ambient environment.

[0107] Among the applicable stabilizers are high molecular weight hindered phenols and polyfunctional phenols, such as sulfur and phosphorus-containing phenols. Hindered phenols are well known to those skilled in the art and can be characterized as phenolic compounds that also contain sterically bulky radicals in close proximity to their phenolic hydroxyl groups. In particular, tertiary butyl groups are generally substituted on the benzene ring in at least one of the ortho positions relative to the phenolic hydroxyl groups. The presence of these sterically bulky substituents near the hydroxyl group serves to suppress its stretching vibration and accordingly its reactivity; this steric hindrance thereby gives the phenolic compound stabilizing properties. Representative hindered phenols include: 1,3,5-trimethyl-2,4,6-tris(3-5-di-tert-butyl-4-hydroxybenzyl)benzene; pentaerythritol tetrakis-3(3,5-di-tert-butyl-4-hydroxyphenyl)propionate; n-octadecyl-3(3,5-di-tert-butyl-4-hydroxyphenyl)propionate; 4.4'-methylenebis(4-methyl-6-tert-butylphenol); 2,6-di-tert-butylphenol; 6-(4-hydroxyphenyl)propionate; 2,3,6-tris(4-hydroxy-3,5-di-tert-butyl-phenoxy)-1,3,5-triazine; di-n-octadecyl-3,5-di-tert-butyl-4-hydroxybenzyl-phosphonate; 2-(n-octyl-thio)ethyl-3,5-di-tert-butyl-4-hydroxybenzoate and sorbitol hexa-3(3,5-di-tert-butyl-4-hydroxy-phenyl)propionate.

[0108] The hot melt adhesive composition according to the invention may further comprise at least one wax, which may be present in the hot melt adhesive composition in a content ranging from 0 to 30% by weight, preferably from 0.5 to 3% by weight, relative to the weight of the composition.

[0109] The presence of waxes makes it possible to reduce the melt viscosity of the hot melt adhesive without appreciably reducing its adhesive bonding properties. These waxes are also used to reduce the open or set-up time of the composition without affecting its temperature performance.

[0110] Among the useful wax materials are: (1) Petroleum waxes such as paraffin wax having a melting point of 50°C to 80°C and microcrystalline waxes having a melting point of 55°C to 100°C (the latter melting points being as determined by ASTM method D127-60); (2) Synthetic waxes made by polymerizing carbon monoxide and hydrogen, such as Fischer-Tropsch wax There is.

[0111] Preferably, the hot melt adhesive composition is free of acid modified waxes, and even more preferably, free of waxes.

[0112] In the present invention, "acid-modified wax" means a wax modified with a carboxylic acid, a carboxylic anhydride, a carboxylic ester or a mixture thereof. It may be, for example, a wax modified with maleic acid or maleic anhydride. An example of an acid-modified wax is an acid-modified polyolefin wax.

[0113] According to a preferred embodiment, the composition of the present invention does not contain any acid-modified components (except for polyolefin copolymer iii), in particular acid-grafted polyolefin copolymer iii-1). Such components may include, for example, acid-modified waxes, acid-modified resins (e.g., petroleum or tackifying resins), acid-modified softeners, acid-modified oils, acid-modified plasticizers or acid-modified rubbers.

[0114] Preferably, the hot melt adhesive composition does not include a propylene homopolymer.

[0115] The viscosity of the hot melt adhesive composition at 160° C. may range from 500 to 10000 mPas, preferably from 1000 to 8000 mPas, even more preferably from 2000 to 6000 mPas. The viscosity may be measured with a Brookfield RVT viscometer (spindle 27) according to the ASTM D3236 standard.

[0116] The softening point of the hot melt adhesive composition may range from 70° C. to 130° C., preferably from 80° C. to 120° C. The softening point can be measured according to the ASTM E-28 standard.

[0117] The hot melt adhesive compositions of the present invention can be formulated using any of the mixing techniques known in the art.

[0118] For example, hot melt adhesives can be prepared by mixing the ingredients in an air atmosphere at a temperature ranging from 150° C. to 180° C. in a mixer consisting of a motor-driven propeller, a heating mantle, and a temperature control unit.

[0119] In one embodiment, the hot melt adhesive composition comprises: - 5% to 30% by weight of said copolymer i); - 2% to 40% by weight of said copolymer ii); - from 2% to 35% by weight of a polyolefin iii), more preferably the above copolymer iii-1); - 25% to 65% by weight of a tackifier may also include

[0120] In a second embodiment, the hot melt adhesive composition comprises: - 5% to 30% by weight of said copolymer i); - 2% to 30% by weight of said copolymer ii); - from 2% to 35% by weight of a polyolefin iii), more preferably the above copolymer iii-1); - 25% to 65% by weight of a tackifier; - 0.5% to 10% by weight of copolymer v) may also include

[0121] B. Use The present invention relates to the use of a hot melt adhesive composition as an adhesive to bond two substrates together or as a coating on the surface of a substrate.

[0122] The surface to be coated may include nonwovens, thin wovens, absorbent fluff, superabsorbent polymers (SAP), composite materials, plastics that may be elastomeric or non-elastomeric, such as styrene block copolymers (SBC), polyurethanes, and polyolefins, and any mixtures thereof.

[0123] Preferably, the surface is a non-woven surface. More preferably, the surface comprises polypropylene (PP), polyethylene (PE), polyethylene terephthalate (PET), cotton, bamboo, silk and / or polylactic acid.

[0124] The present invention also provides a method for producing an assembly (or laminate) comprising: - step (i) of heating the hot melt adhesive composition according to the invention at a temperature, for example in the range of 120°C to 180°C, for at least a time long enough to make the hot melt adhesive composition sufficiently liquid for application onto a substrate (for example at least 2 hours), then - (ii) coating said composition onto a first substrate, and then - (iii) contacting the coated surface of the first substrate with a surface of the second substrate so as to form an adhesive bond joining the two substrates. The present invention also relates to a method, comprising:

[0125] The substrates may be of different or the same nature, in various forms (layers or films, strands, fluff).

[0126] Preferably, each substrate, independently of the other, may be selected from among nonwovens, tissues, absorbent fluff, superabsorbent polymers (SAPs), composites, plastics which may be elastic or non-elastic and may be selected from, for example, styrene block copolymers (SBCs), polyurethanes, and polyolefins, and any mixtures thereof.

[0127] Compositions according to the present invention can be coated or applied by a variety of application techniques known in the art, including contact application (such as slot die coating) and non-contact application (such as spraying or fiberizing).

[0128] The present invention also relates to an article comprising at least one interior or exterior surface coated with the above-described hot melt adhesive composition.

[0129] Preferably, the interior or exterior surface of the article is a nonwoven.

[0130] The article may be selected from a disposable diaper, a disposable training pant, a feminine sanitary napkin, an absorbent pad, or a surgical mask.

[0131] The present invention also relates to the use of the hot melt adhesive composition defined herein as a construction adhesive in disposable articles.

[0132] The hot melt composition according to the invention advantageously results in good adhesion in nonwoven material-based products, and more particularly in hydrophilic nonwoven material-based products, in particular laminates with good both dry and wet adhesive strength.

[0133] According to the present invention, "occupying between x and y" or "in the range of x and y" means a range that includes the limits x and y. For example, the range "occupying between 1% and 3%" specifically includes 1% and 3%.

[0134] The following examples are set forth merely to illustrate the invention and should not be construed in any way as limiting its scope. EXAMPLES

[0135] The following ingredients were used for the preparation of the hot melt adhesive compositions: - VESTOPLAST® 308 (commercialized by EVONIK): maleic anhydride grafted 1-butene rich alpha olefin copolymer with density 0.87 g / cm3 and Mw 49000 g / mol; - VISTAMAXX® 8880 (commercialized by EXXONMOBIL): a metallocene-catalyzed copolymer composed mainly of isotactic propylene repeat units with 6% by weight of ethylene, with a density of 0.880 g / cm3 and Mw of 27000 g / mol; - VISTAMAXX® 8380 (commercialized by EXXONMOBIL): a metallocene-catalyzed copolymer composed mainly of isotactic propylene repeat units with 12% by weight of ethylene, with a density of 0.864 g / cm3 and Mw of 43000 g / mol; - C115W (commercialized by Nanjing Yangzi Eastman Chemical Ltd.: hydrogenated hydrocarbon resin; - N4010 (commercialized by Sinopec Karamay): naphthenic oil; - FB8925 (commercialized by Fine Blend Compatibilizer Jiangsu Co Ltd): maleic anhydride grafted ethylene-propylene copolymer; - IRGANOX 1010 (commercialized by BASF): Phenolic primary antioxidant: pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl))propionate

[0136] The viscosity of the compositions was measured at 160°C using a Brookfield RVT viscometer using a n°27 spindle.

[0137] The softening point of the composition was measured according to the ASTM E-28 standard.

[0138] A1-Preparation of hot melt adhesive compositions The composition of Example 1 in Table 1 according to the present invention is prepared by simple mixing of the ingredients. The ingredients were placed in a jacketed mixing kettle equipped with a heater and stirrer, and then mixed with heating at 160° C. for 120 minutes. TIFF2024543171000001.tif158170

[0139] A2-Dry and wet peel strength Laminated specimens were made using a laboratory coater at 150 meters per minute.

[0140] The hot melt adhesive composition is first heated at a temperature of 155°C and then coated at a rate of 4 to 10 g / m2 by slot coating with various open times (typically 0.05 to 0.4 seconds) and nip roll compression from 0.1 bar to 40 bar. 2 (depending on the substrate) onto a nonwoven (15 gsm hydrophilic spunbond nonwoven as the first substrate). The nonwoven coated with the hot melt adhesive composition and the air-through nonwoven, polyethylene film or pure cotton were stacked together by the hot melt adhesive to obtain a laminate (NW / air-through NW, NW / PE, or NW / cotton).

[0141] The laminate is then stored at 25° C. for 24 hours in an atmosphere of 50% relative humidity to cool and solidify the hot melt adhesive. The laminate is then cut into test specimens 25 mm wide and 100 mm long.

[0142] A T-peel test is carried out at 25° C. and 50% RH by pulling apart wet test specimens at a speed of 300 mm / min to measure the dry peel strength.

[0143] Alternatively, the test specimen is immersed in 0.9% salt-containing solution at 25°C for 1 minute, and then wiped to obtain a wet test specimen. Then, the wet test specimen is peeled at a speed of 300mm / min at 25°C and 50% RH to perform a T-peel test to measure the wet peel strength. TIFF2024543171000002.tif121170

[0144] The compositions of the present invention advantageously make it possible to achieve both good dry and wet peel strengths on a variety of substrates.

Claims

1. i) a first metallocene-catalyzed propylene-based copolymer; ii) a second metallocene-catalyzed propylene-based copolymer; iii) iii-1) Acid-grafted polyolefin copolymer; iii-2) copolymers based on olefins and unsaturated monomers containing acid or anhydride groups; and iii-3) Mixtures of these a polyolefin copolymer selected from the group consisting of: iv) tackifiers; v) an optional third metallocene-catalyzed propylene-based copolymer 1. A hot melt adhesive composition comprising: A hot melt adhesive composition wherein each of the metallocene-catalyzed propylene-based copolymers i) and ii) independently of the other comprises from 1 wt. % to 20 wt. % of ethylene units.

2. 2. The hot melt adhesive composition according to claim 1, wherein the first metallocene-catalyzed propylene-based copolymer i) comprises more than 60 wt.%, preferably more than 70 wt.%, even more preferably more than 80 wt.%, advantageously more than 85 wt.% of propylene units, based on the weight of the copolymer.

3. 2. The hot melt adhesive composition of claim 1, wherein the first metallocene-catalyzed propylene-based copolymer i) has a glass transition temperature of from −75° C. to −10° C., preferably from −50° C. to −15° C., and even more preferably from −35° C. to −20° C.

4. 2. The hot melt adhesive composition of claim 1, wherein the viscosity of the first metallocene-catalyzed propylene-based copolymer i) at 190°C ranges from 700 mPas to 10,000 mPas, preferably from 1,000 to 10,000 mPas, and even more preferably from 2,000 to 9,000 mPas.

5. 2. The hot melt adhesive composition of claim 1, wherein the first metallocene-catalyzed propylene-based copolymer i) has an enthalpy of melting, as determined by DSC, of ​​greater than 20 J / g, preferably greater than 30 J / g, and even more preferably greater than 35 J / g.

6. 2. The hot melt adhesive composition according to claim 1, wherein the second metallocene-catalyzed propylene-based copolymer ii) comprises more than 60 wt.%, preferably more than 70 wt.%, even more preferably more than 80 wt.%, advantageously more than 85 wt.% of propylene units based on the weight of said copolymer ii).

7. 2. The hot melt adhesive composition of claim 1, wherein the second metallocene-catalyzed propylene-based copolymer ii) has a glass transition temperature of from −75° C. to −10° C., preferably from −50° C. to −15° C., and even more preferably from −35° C. to −20° C.

8. 10. The hot melt adhesive composition of claim 1, wherein the second metallocene-catalyzed propylene-based copolymer ii) has an enthalpy of melting of from 5 J / g to 10 J / g.

9. The acid-grafted polyolefin copolymer iii-1) has a viscosity of 0.86 to 0.89 g / cm ３ , preferably 0.865 to 0.88 g / cm ３ 10. The hot melt adhesive composition of claim 1, having a density of

10. 2. The hot melt adhesive composition of claim 1, wherein the acid-grafted polyolefin copolymer iii-1) has a weight average molecular weight (Mw) in the range of 20,000 g / mol to 80,000 g / mol, preferably 30,000 g / mol to 70,000 g / mol.

11. 2. The hot melt adhesive composition of claim 1, wherein the acid-grafted polyolefin copolymer iii-1) has a viscosity at 190°C of 2000 mPa.s or more, more preferably 4000 mPa.s or more, and even more preferably 6000 mPa.s or more.

12. 2. The hot melt adhesive composition of claim 1, wherein the acid-grafted polyolefin copolymer iii-1) is an acid-grafted copolymer of ethylene and propylene or an acid-grafted terpolymer of ethylene, propylene and 1-butene.

13. 2. The hot melt adhesive composition of claim 1, wherein the acid-grafted polyolefin copolymer iii-1) is a maleic anhydride-grafted polyolefin copolymer.

14. copolymer iii-2) comprises more than 50% by weight, more preferably more than 60% by weight, even more preferably more than 70% by weight of olefin units relative to the total weight of said copolymer iii-2); and / or 2. The hot melt adhesive composition of claim 1, wherein copolymer iii-2) comprises less than 10 wt. %, more preferably less than 5 wt. %, based on the total weight of said copolymer iii-2), of unsaturated monomers containing acid or anhydride groups.

15. 2. The hot melt adhesive composition of claim 1, wherein the third metallocene-catalyzed propylene-based copolymer v) has a melt flow rate in the range of from 3 g / min to 100 g / min, preferably from 8 g / min to 80 g / min, more preferably from 10 g / min to 60 g / min.

16. (a) aliphatic and cycloaliphatic petroleum hydrocarbon resins having a ring and ball softening point of from 90°C to 160°C as determined by ASTM method E28-58T, the latter resins being produced by polymerization of monomers consisting primarily of aliphatic and / or cycloaliphatic olefins and diolefins; including hydrogenated aliphatic and cycloaliphatic petroleum hydrocarbon resins; (b) aromatic petroleum hydrocarbon resins and their hydrogenated derivatives; (c) aliphatic / aromatic petroleum-derived hydrocarbon resins and their hydrogenated derivatives; (d) aromatic-modified cycloaliphatic resins and hydrogenated derivatives thereof; (e) Polyterpene resins having a softening point of 95°C to 140°C, the latter polyterpene resins generally being produced from the polymerization of terpene hydrocarbons, such as the monoterpene known as pinene, in the presence of a Friedel-Crafts catalyst at moderately low temperatures; hydrogenated polyterpene resins are also included; (f) copolymers and terpolymers of natural terpenes; (g) Natural and modified rosins such as, for example, gun rosin, wood rosin, tall oil rosin, distilled rosin, hydrogenated rosin, dimerized rosin, and polymerized rosin; (h) Glycerol and pentaerythritol esters of natural and modified rosins, such as, for example, glycerol esters of pale wood rosin, glycerol esters of hydrogenated rosin, glycerol esters of polymerized rosin, pentaerythritol esters of pale wood rosin, pentaerythritol esters of hydrogenated rosin, pentaerythritol esters of tall oil rosin, and phenol-modified pentaerythritol esters of rosin; (i) phenol-modified terpene resins, such as resin products produced from the condensation of terpenes and phenols in an acidic medium; (j) Mixtures of these 10. The hot melt adhesive composition of claim 1, comprising a tackifier selected from the group consisting of:

17. 10. The hot melt adhesive composition of claim 1, wherein the hot melt adhesive composition is free of acid-modified tackifiers.

18. 2. The hot melt adhesive composition according to claim 1, characterized in that it contains a plasticizer preferably selected from naphthenic oils, paraffinicoils, polyisobutylenes, benzoic acid esters, and mixtures thereof.

19. 2. The hot melt adhesive composition of claim 1, characterized in that it is free of acid-modified waxes, more preferably free of waxes.

20. 2. The hot melt adhesive composition according to claim 1, having a viscosity at 160°C in the range of from 500 to 10000 mPas, preferably from 1000 to 8000 mPas, even more preferably from 2000 to 6000 mPas.

21. - 5% to 30% by weight of copolymer i); - 2% to 40% by weight of copolymer ii); - 2% to 35% by weight of polyolefin iii), more preferably copolymer iii-1); - 25% to 65% by weight of a tackifier 10. The hot melt adhesive composition of claim 1, comprising:

22. 2. The hot melt adhesive composition of claim 1, which is free of propylene homopolymers.

23. 10. Use of the hot melt adhesive composition of claim 1 as an adhesive to bond two substrates together or as a coating on the surface of a substrate.

24. (i) heating the hot melt adhesive composition according to claim 1 at a temperature in the range of, for example, 120°C to 180°C for a time at least long enough to make the hot melt adhesive composition sufficiently liquid for application onto a substrate, then (ii) coating said composition onto a first substrate, and then - (iii) contacting the coated surface of the first substrate with a surface of the second substrate so as to form an adhesive bond joining the two substrates; 1. A method for manufacturing an assembly (or laminate), comprising: