Holm Aldridge does not contain any hardening compound

Abstract

To provide a curable aqueous formulation for a binder used in textile and nonwoven applications, where the binder is free from formaldehyde and has properties comparable to an N-methylolacrylamide (NMA)-containing binder.SOLUTION: A curable aqueous formulation comprises a) an emulsion polymer containing 0.1 to 20 wt.% of acid monomers, b) an oxazoline-containing polymer, and c) an aqueous acrylic polymer dispersion containing 40 to 100 wt.% of acid monomers and having a weight average molecular weight in the range from 2000 to 500000.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to binders for woven and nonwoven applications. [Background technology]

[0002] Traditional binders used in woven and nonwoven applications are characterized by their excellent water resistance (wetness) after curing. N is used as a functional monomer to provide wet strength and solvent resistance (isopropyl alcohol strength). -Contains methylol acrylamide (NMA). However, NMA-containing binders , which releases formaldehyde when heated. One solution that has been used in the past is itaconic acid. This technology has good water and solvent resistance after curing. It has good resistance to formaldehyde but lacks the excellent properties of NMA-containing binders. A method that is free of EDTA and has comparable properties is desired. Summary of the Invention

[0003] One aspect of the invention is a curable aqueous formulation comprising: a) 0.1 to 20 weight percent of an acid a) an emulsion polymer comprising a monomer; b) an oxazoline-containing polymer; and c) a 40- Contains 100 weight percent acid monomer and has a weight average molecular weight in the range of 2,000 to 500,000. and an aqueous acrylic polymer dispersion having a molecular weight of It consists of them. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0004] The present invention provides a method for forming an aqueous curable formulation.

[0005] "Aqueous" as used herein means that the continuous phase is water or in the alternative. Contains primarily water, but also water-miscible solvents, biocides, emollients, buffers, chelating agents, and a surfactant, and optionally other ingredients.

[0006] As used herein, a "woven fabric" is a fabric made up of long threads running in one direction and other threads at right angles to each other. A cloth-like fiber, typically in the form of a sheet or fabric, formed by combining It means a collection of fibers.

[0007] As used herein, "nonwoven" refers to a material that is not woven or knitted, typically a sheet. Nonwoven substrates refer to a collection of fibers in the form of a cloth or fabric. Nonwoven substrates include felts and mats, or other aggregates of fibers. Nonwoven substrates include cotton, rayon, and Cellulosic fibers such as wood pulp, polyester, glass, and synthetics such as nylon Fibers, composite fibers, and mixtures thereof. For example, wet laid, air laid, spunbonded, The prior art techniques include spun melt, spun melt, and hydroentangling web formation. The material may be formed by known methods in the art.

[0008] The curable aqueous formulation comprises: a) an emulsion containing 0.1 to 20 weight percent of an acid monomer; b) an oxazoline-containing polymer; and c) 40 to 100 weight percent of an acid A water-based acrylic resin containing a monomer and having a weight average molecular weight in the range of 2,000 to 500,000. and a polymer dispersion.

[0009] Component A - Emulsion Polymer The aqueous nonwoven binder comprises an emulsion polymer, which is prepared by an aqueous emulsion polymerization process. It is a polymer prepared by free radical polymerization of ethylenically unsaturated monomers in The emulsion polymer contains, as copolymerized units, Contains 0.1 to 20 weight percent acid monomer. All ranges between 1 and 20 cents are included herein and disclosed herein, for example, The weight percent of the acid monomer may be increased from lower limits of 0.1, 5, 7, or 10 to 12, 15, or 1 It can be as high as 8, or as high as 20.

[0010] The emulsion polymer also has a weight average molecular weight of 5,000 to 500,000. Any and all ranges between 5,000 and 500,000 are included herein and are not intended to be limiting unless otherwise specified. For example, the emulsion polymer is 50,000 to 400,000 or 10 The weight average molecular weight may be from 0,000 to 300,000.

[0011] The acid monomers may include mono-acid monomers and di-acid monomers. For example, acrylic acid, methacrylic acid, crotonic acid, monomethyl itaconate, monomethyl Examples of the carboxylic acid monomers include dibutyl fumarate, monobutyl fumarate, and the like. Examples of acid monomers include itaconic acid, fumaric acid, including its anhydrides, salts, and mixtures thereof. Examples of the carboxylic acid include, but are not limited to, maleic acid and maleic acid.

[0012] Emulsion polymers also include, for example, methyl (meth)acrylate, ethyl (Meth)acrylate, Butyl (Meth)acrylate, 2-Ethylhexyl (Meth)acrylate acrylate, decyl (meth)acrylate, hydroxyethyl (meth)acrylate, propyl(meth)acrylate, ureido-functional (meth)acrylate, and (meth)acrylate (Me) Acrylic acid acetoacetate, acetamide, or cyanoacetate p) Acrylic ester monomer, styrene or substituted styrene, vinyl toluene, butadiene Dienes, vinyl acetate or other vinyl esters, vinyl chloride, vinylidene chloride, etc. Such a vinyl monomer and at least one other copolymer such as (meth)acrylonitrile. (Meth)acrylic acid and ethylenically unsaturated monomers are used throughout this disclosure. The term "(meth)" followed by other terms such as (meth)acrylamide or (meth)acrylamide Use is made of acrylate and methacrylate or acrylamide and methacrylate, respectively. Mixtures of emulsion polymers having different compositions may also be used. It can be done.

[0013] Emulsion polymers are 80 to 99.8 percent by weight on a dry solids basis. In various other embodiments, the emulsion polymer is present in the formulation in the range of 8 It may be present in the range of 2 to 99.8 weight percent, and in various other embodiments, 85 to 9 It is 9.8 percent by weight.

[0014] Component B - Oxazoline-containing polymer The formulation also includes at least one oxazoline-containing polymer as a crosslinker. In certain embodiments, the oxazoline-containing polymer comprises an addition polymerizable oxazoline and at least The method comprises the steps of: mixing one or more ethylenically unsaturated monomers (as listed above) in an aqueous solvent according to the methods of the art; By carrying out a solution polymerization reaction or emulsion polymerization using any suitable polymerization process known to those skilled in the art. In various embodiments, an addition polymerization reaction occurs.

[0015] In various embodiments, the oxazoline-containing polymer has a structure according to the formula shown below: do.

[0016] [ka]

[0017] In the formula, R 1 , R 2 , R 3 , and R 4 are independently a hydrogen atom, a halogen atom, an alkyl R represents a group, an aralkyl group, a phenyl group, or a substituted phenyl group. 5 is an addition polymerizable unsaturated bond represents a non-cyclic organic group having the following formula:

[0018] In some embodiments, the oxazoline-containing polymer has 2-oxazoline groups. .

[0019] Examples of oxazoline-containing polymers include 2-vinyl-2-oxazoline, 2-vinyl -4-methyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, 2-iso 2-Isopropenyl-2-oxazoline, 2-Isopropenyl-4-methyl-2-oxazoline , 2-isopropenyl-5-ethyl-2-oxazoline, 2-isopropenyl-4-hydro 4-ethyl-2-oxazoline, 2-(I-hexadecylvinyl)-4, 4-(bis(stearoyloxymethyl)-2-oxazoline, 2-(I-eicosylvinyl) 2-isopropenyl-4,4-bis(hydroxymethyl)-2-oxazoline ,4-Bis(hydroxymethyl)-2-oxazoline, 2-isopropenyl-4,4-bi Examples of vinyloxazolines include 2-(methyl)-2-oxazoline. Not limited.

[0020] The oxazoline-containing polymer is generally in the range of 0.1 to 10 parts by weight based on dry solids. The oxazoline-containing polymer is present in the formulation in the range of 100%. In some embodiments, it may be present in the range of 1 to 8 weight percent, and in various other embodiments, 3 ~7 weight percent.

[0021] Component C - Water-Based Acrylic Polymer Dispersion The formulation also includes an aqueous acrylic polymer dispersion. , 40 to 100 weight percent acid groups. , 50 to 95 weight percent acid groups, and in various other embodiments, 65 to 80 The weight percent of acid groups in the aqueous acrylic polymer dispersion is also 2000 to 500 The dispersion has a weight average molecular weight in the range of 50,000. In various other embodiments, the polymer may have a weight average molecular weight of 10,000 to 400,000. 0000~350000.

[0022] The aqueous acrylic polymer dispersion also contains one or more of the ethylenically unsaturated monomers listed above. It may be formed from any of the following:

[0023] The aqueous acrylic polymer dispersion generally has a weight percent of 0.1 to 10% by weight on a dry solids basis. The dispersion is present in the formulation in a range of 1 to 5 percent in various other embodiments. 8 weight percent, and in various other embodiments, 3 to 7 weight percent. It is.

[0024] Optional Ingredients The aqueous nonwoven binder may also contain, for example, emulsifiers, pigments, fillers or extenders, Anti-glution agents, coalescents, surfactants, biocides, plasticizers, organosilanes, defoamers , conventional processing ingredients such as corrosion inhibitors, colorants, waxes, other polymers, and antioxidants. may be mentioned.

[0025] Emulsion polymerization techniques used to prepare emulsion polymers are described, for example, in U.S. Pat. Nos. 4,325,856, 4,654,397, and 4,814,373 As disclosed herein, the emulsion polymerization process is known in the art. In this case, the initiation process (e.g., heat or reduction-oxidation reaction) can cause the temperature to rise from room temperature to 100°C. For example, alkali metal or ammonium alkyl sulfates are used. , alkyl sulfonic acids, fatty acids, copolymer surfactants, and oxyethylated alkyl phenols. Conventional surfactants such as anionic and / or nonionic emulsifiers, such as ethanol, are used. Anionic emulsifiers are preferred. The amount of surfactant used is based on the weight of the total monomers. Based on the thermal or reduction-oxidation reaction initiation process, it is usually 0.1% to 6% by weight. Either can be used. Typically, the amount is 0.01% to 3% by weight based on the weight of the total monomer. At a concentration of .0% by weight, for example, hydrogen peroxide, t-butyl hydroperoxide, t-amyl Hydroperoxides, ammonium and / or alkali persulfates, and azobis Conventional free radical initiators such as water-soluble azo compounds such as sucrose valeric acid can be used. In one embodiment, the initiator is present in an amount of 0.5% by weight to 1. 5% by weight. For example, sodium formaldehyde sulfoxylate, hydo Rosulfite, isoascorbic acid, hydroxylamine sulfate, and sulfurous acid water A reduction-oxidation reaction method using the same initiator coupled with a suitable reducing agent such as sodium nitrate is also disclosed. , optionally in combination with metal ions, such as iron and copper, optionally further comprising a complexing agent for the metal. Chain transfer agents such as mercaptans can be used in the same concentrations as the polymers. The monomer mixture can be used to emulsion without water or in water. The monomer mixture may be added in a single addition or multiple additions, and The additive may be added continuously over the reaction period, either uniformly or using a varying composition. Before, during, or after any step, a free radical initiator, an oxidizing agent, a reducing agent, Additional ingredients such as chain transfer agents, neutralizing agents, surfactants, and dispersants may be added. In one embodiment, the emulsion polymer comprises at least two emulsions that differ in composition. It may be prepared by a multi-stage emulsion polymerization process in which the stages are polymerized in a sequential manner. The molecular weight of the polymer falls within the above molecular weight range. The oxazoline-containing polymer and The aqueous acrylic polymer dispersion may, in some embodiments, be mixed with water while stirring or agitating. It may be added to the emulsion polymer with stirring.

[0026] The average particle size of the emulsion polymer particles was measured using a Brookhaven Instrument Supplied by Brookhaven T Corp., Holtsville, NY As measured by a Model BI-90 Particle Sizer, Typically, 30 nanometers to 1000 nanometers, preferably 100 nanometers ~200 nanometers.

[0027] A woven or nonwoven substrate is contacted with the curable aqueous formulation. Typically, The ratio of the contacted substrate to the dry weight basis expressed as a percentage, also known as % The ratio of the mixture is selected according to the strength of the substrate and the desired end use, preferably 1% to 40%. The substrate is applied by air or airless spraying, padding, etc. Conventional applications such as coating, impregnation, roll coating, curtain coating, gravure printing, and the like. The substrate is contacted with the curable aqueous formulation using any suitable technique. can be contacted with a curable aqueous formulation to provide a binder on or near Alternatively, the particles may be distributed unevenly or not throughout the structure. If a uniform distribution is desired, the curable aqueous formulation may be applied non-uniformly to one or both surfaces. It is contemplated that the present invention may be applied in a variety of ways.

[0028] In a method for forming a substrate containing the curable aqueous formulation of the present invention, The substrate in contact with the curable formulation is subjected to a temperature of 120°C to 220°C for a time sufficient to effect cure. The heating is preferably performed at 140°C to 180°C.

[0029] The curable aqueous formulations of the present invention are also useful in pressure sensitive adhesives and lamination applications, in addition to textile and nonwoven applications. It may be used to make a layer adhesive. EXAMPLES

[0030] Abbreviations used: IPA: Isopropanol DI water: Deionized water CD: Width direction SC: solid content BA: Butyl acrylate Sty: styrene IA: Itaconic acid AA: Acrylic acid DS-4: Sodium dodecylbenzenesulfonate, surfactant TR-407: Current commercial products based on NMA technology using formaldehyde (HCHO) SWX1116(A): Emulsion containing 49Sty / 46BA / 3AA / 2IA in polymer containing 45% SC EPOCRS WS500(B): A polymer solution containing oxazoline groups from Nippon Shokubai, containing 40% SC and 4.5 mmol / g oxazoline solids. Leukotan 1084(C1): from The Dow Chemical Company containing 100% AA and 28% SC liquid ASE60(C2): An emulsion polymer from The Dow Chemical Company containing 40% AA and 28% SC TRITON™ X-100: A surfactant from The Dow Chemical Company WHATMAN(TM): #4 Paper from Whatman Ltd.

[0031] The invention Reference example 1 and Example 1 And Comparative Examples 1 and 2 The above raw materials were blended with proper stirring for 30 minutes to obtain a curable aqueous composition according to the formulations in Tables 1 and 2.

[0032] [Table 1]

[0033] [Table 2]

[0034] A 28cm x 46cm strip of WHATMAN™ paper was placed in a 200mL blended emulsion. The treated substrate was padded with a Mathis padder and then The paper was then dried and cured at 150°C for 3 minutes. The amount of polymer on the paper was 28% in Table 1. The cured substrate was placed on a 1" x 4" plate. The tensile strength of the specimens was measured at 40°C for 10 min. Dry (untreated), wet (after immersion in 0.1% Triton X-100 / water solution for 30 minutes) ), and IPA (after 30 minutes in isopropanol). The IPA strength reflects the resistance of the binder to water, and the IPA strength reflects the resistance of the binder in solvent. Shown in Tables 3 and 4.

[0035] [Table 3]

[0036] The results in Table 3 show: • Higher values ​​of strength result in better performance. All the examples, except for Comparative Example 1, do not contain HCHO. Comparative Example 1 is based on NMA technology containing HCHO and has the best overall performance showed. Comparative Example 3 exhibited better IPA strength than Comparative Example 2a. Comparative Example 4 contained a low molecular weight acid, and the performance was not improved from Comparative Example 3. Comparative Examples 5 and 6 have a high acid polymer (C) and do not contain a polymer-containing oxazoline. There was no improvement in overall performance from Comparative Example 2a.

[0037] [Table 4]

[0038] overview: Compared to Comparative Example 2b, Reference example 3 and Reference example 4 showed greater than 10% improvement in wet strength and at least 20% increase in IPA strength. Compared to Comparative Example 2b, Reference example 2 and 5 showed wet strength lower than 15% and increased by more than 65% with respect to IPA strength. ●Invention Reference example 3 and 5 Comparing the above, it is found that when component C increases by 0.1% to 10%, the IPA strength increases by 2.8 to 3.81.

Claims

1. 1. A curable aqueous formulation comprising: a) an emulsion polymer comprising 5 to 20 weight percent acid monomer; b) an oxazoline-containing polymer; and c) an aqueous acrylic polymer dispersion comprising 40 to 100 weight percent acid monomer and having a weight average molecular weight in the range of 2,000 to 500,000; 1. A curable aqueous formulation comprising:

2. 10. The curable aqueous formulation of claim 1, wherein the emulsion polymer is present in an amount ranging from 80 to 99.8 weight percent, the oxazoline-containing polymer is present in an amount ranging from 0.1 to 10 weight percent, and the aqueous acrylic polymer dispersion is present in an amount ranging from 0.1 to 10 weight percent on a dry solids basis.

3. 10. The curable aqueous formulation of claim 1, wherein the emulsion polymer comprises styrene, butyl acrylate, acrylic acid, and itaconic acid.

4. The curable aqueous formulation of claim 1, wherein the oxazoline-containing polymer has at least one 2-oxazoline group.

5. 2. The curable aqueous formulation of claim 1, wherein the oxazoline-containing polymer is selected from the group consisting of 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, 2-isopropenyl-2-oxazoline, 2-isopropenyl-4-methyl-2-oxazoline, 2-isopropenyl-5-ethyl-2-oxazoline, 2-isopropenyl-4-hydroxymethyl-4-ethyl-2-oxazoline, 2-(I-hexadecylvinyl)-4,4-(bisstearoyloxymethyl)-2-oxazoline, 2-(I-eicosylvinyl)-4,4-bis(hydroxymethyl)-2-oxazoline, 2-isopropenyl-4,4-bis(hydroxymethyl)-2-oxazoline, 2-isopropenyl-4,4-bis(methyl)-2-oxazoline, and mixtures thereof.

6. A method for forming the curable aqueous formulation of claim 1, comprising: a) emulsion polymerizing at least one monoethylenically unsaturated monomer and at least one acid monomer in an aqueous solution to form said emulsion polymer; b) adding said oxazoline-containing polymer and said aqueous acrylic polymer dispersion to said emulsion polymer to form said curable aqueous formulation.

7. 13. A method for forming a cured substrate comprising the curable aqueous formulation of claim 1, comprising: a) contacting a woven or nonwoven substrate with the curable aqueous formulation to form a contacted substrate; b) heating the contacted nonwoven substrate to a temperature of from 120° C. to 220° C. to form the hardened substrate.

8. a) a woven or nonwoven substrate; b) a binder comprising the curable aqueous formulation of claim 1.

9. A pressure sensitive adhesive comprising the curable aqueous formulation of claim 1.

10. A lamination adhesive comprising the curable aqueous formulation of claim 1.

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