TW200809043A - Covalent bonding of carboxylated cellulose fiber webs - Google Patents

Abstract

Methods are provided for creating covalent bonding of webs by combining cellulosic fibers having a carboxyl content approximately greater than 7 meq/100g with one or more crosslinking agents. In a first step, a carboxyl group is placed onto a fiber. In an embodiment, the fiber is then reacted with an oxazoline-functional polymer which has been combined with a polycarboxylate compound. Heat is applied to the treated web, and this enables formation of a cross-linked bridge in the form of a covalent bond. In an embodiment, the covalent bonding of the carboxylated cellulose pulp webs utilizes oxazoline-functional polymers and polyacrylic acid. The oxazoline polymer in combination with polyacrylic acid should form a network polymer with covalent bonds to the cellulose carboxyl groups. The non-woven web may be strengthhened by covalent bonding, thereby improving overal wet/dry strength of the final product.

Description

200809043 IX. DESCRIPTION OF THE INVENTION: TECHNICAL FIELD OF THE INVENTION The present invention generally relates to a method of providing a covalent bond on a cellulosic fiber web. [Prior Art] Cellulose fibers are usually solidified by hydrogen bonding to the strength of the 1-5 Kca paper product, usually in an attempt to strengthen the bonding of the fibers. In some cases, it is undesirable to increase the knot. Set together. The average energy of hydrogen bonds is often related to the strength of hydrogen bonding. Damage to other strengths such as volume, hardness, etc., increases the total cost of the product, and there is still a need to increase the bond strength between the cellulosic fibers without compromising the properties of the final product. SUMMARY OF THE INVENTION The present invention provides a covalent knot for a web by combining cellulose fibers having substantially more than 7 mils and one or more cross-linking agents.

Combined method. In the first step, the carboxyl group is placed on the fiber. In one embodiment, the fibers are then combined with the poly(tetra)-compound. Evil (four) functional polymer reaction. Heating the treated web enables the formation of a bridge in the form of a covalent bond. In the embodiment, the covalent bonding of the cellulose esterified cellulose paper web utilizes an oxazoline functional polymer and polyacrylic acid. The oxazoline poly-substance X and polypropylene k should form a network polymer covalently bonded to the cellulose suspending group. Nonwoven webs can be strengthened by covalent bonding, thereby improving the overall wet/dry strength of the final product. Figure 2 illustrates a general class of polymers functionalized with oxazoline groups. 121329.doc 200809043 Wood: IT knows that papermaking fibers, and the ingredients for which it is used may refer to papermaking fibers made from hard materials and may have been coated with pine nuts and otherwise not followed by pulping/bleaching or offline. Pulp "whitening and drying chemically treated fibers. The cut, quasi-fibril fibers may be obtained from any source including cotton, hemp, kansui husk, corn stalks, or other suitable source. In the implementation of the fiscal, cellulose fiber chemical wood pulp. The ^ 1 σ heart-possin functional polymer may be any polymer containing a oxa 2: ρ knife on the side chain. A polyfunctional compound capable of reacting with a carboxyl group (e.g., a polyol, a polyepoxide, etc.) may be used in place of the polymer containing the wood. For example, a polyphenolic acid vinegar compound can be a polymer or oligomer containing a plurality of sulfhydryl groups. The cross-linking agent may include a catalyst for accelerating the binding reaction between the cross-linking agent and the cellulose molecule. J g Most of the parent-linking agent does not require a catalyst. Suitable catalysts include acid salts which are useful when using urea-based cross-linking materials. Such salts include ammonium chloride, ammonium sulfate, aluminum chloride, magnesium chloride or mixtures of such compounds or other similar compounds. It can also be used to test the metal salt of the acid. The crosslinker is typically applied in an amount ranging from about 8 kg to about 100 kg of chemical per ton of cellulosic fiber. The polyphthalic acid brewing compound is typically applied in an amount ranging from about 8 kg to about (10) kg of chemical per gram of fiber. The cellulosic fibers can be treated with a debonding agent prior to treatment with the crosslinking agent. The debonder tends to minimize interfiber bonding and to make the fibers more easily separated from each other. The debonding agent can be cationic, nonionic or anionic. Cationic detergents appear to be superior to nonionic or anionic detergents. The debonder 121329.doc 200809043 is typically added to the cellulosic fiber feedstock. Suitable cationic debonders include quaternary ammonium salts. Such salts typically have - or two lower alkyl substituents and one or two substituents which are aliphatic, relatively long chain hydrocarbons or contain fatty, relatively long chain hydrocarbons. The nonionic type A 彳 通# contains a reaction product of a fatty aliphatic alcohol, a fatty alkyl phenol, and a fatty aromatic acid and a fatty acid reacted with ethylene oxide, propylene oxide or a mixture of these two substances. Examples of the release agent can be found in U.S. Patent Nos. 3,395,7,8 and 3,544,862 to Hervey et al., and U.S. Patent No. 4,144,122 to Emanuelsson et al. 〇1^1)1, et al., U.S. Patent No. 3,677,886, issued to U.S. Patent No. 4,351,699, to U.S. Patent No. 4, 476, 323 to Hellst, et al. The patents are hereby incorporated by reference in their entirety. Suitable for the release of J from Berol Chemicals, Incorporated of Metairie, La

Berocell 584. The debonder weight can be used in an amount of 〇 25% by weight of the fiber. Again, a debonder may not be needed. In Fig. 1, the conveyor belt 12 transports the cellulose mat 14 into the treatment zone 16 where the applicator 18 applies a crosslinker to the mat 14. Typically, chemicals are applied to both sides of the mat as appropriate. The tweezers 14 are then transferred to the dryer 20 where they are then passed through an oven 22 to cure the crosslinker. The treated liner has a low density and good hardness. The liner can be easily cut with a sharp knife. The material is absorbent and stable even when wet. [Embodiment] The present invention can be better understood by the following examples. It is to be understood that in the following examples, the method described in U.S. Patent Nos. 6,379,494, 6,352,348 and 6,919,447, the disclosure of which is incorporated herein by reference. Example 1: Ep〇cros WS5 00 to polyacrylic acid ratio A fluff pulp having a carboxyl group content of 21 meq/l 〇〇 g was modified to prepare a 125 gsm 6 吋 airlaid pad. The carboxylated pulp may be present in a neutralized form or in a fully protonated (acid) form. Use 1〇 gm*Nipp〇n

A spray spray pad of oxazoline functional polyacrylate (Ep〇cr〇s WS5〇〇) manufactured by Shokubai and polyacrylic acid (MW: about 3500) from R〇hm & Haas, which is shown in the table below. Ep〇cr〇s and polyacrylic acid are included. The Epocros content varies from 3% to 7% by weight of the fiber, and the polyacrylic acid content varies from 1% to 5% by weight of the fiber. The control liner contained only poly-tenoic acid. The liner was dried at 120 t: in a convection oven and cured to dryness. The wet tensile strength and dry tensile strength of the liner were then tested using a vertical traction (10) test apparatus/system. For wet stretching, the liner was sprayed with 10 gm of deionized water, allowed to stand for 1 minute, and then tested. It can be seen from Table 1 that the strength value is increased due to an increase in the polymer content, and the dry tensile index is greatly increased. The data also show that higher intensity values are obtained from the derogatory form of the acidified paper. Similar results for the wet tensile index are shown in Table 2. Table 1: Dry Tensile Index, Nm/g

121329.doc 200809043 7% - Tensile and the tensile index of the form 0.83 -. 1.20 2.02 _____ " χωΓ 2.29 ___4〇0 JW 4.40 3.74 5.15 Table 2 · Concentrated tensile index, Nm/g

5% 0.49 0.65 1.18 1.24 0.49 0.37 0.69 0.75 Example 2: Effect of increasing the carboxyl group content in the pulp Using a fluff pulp modified with a carboxyl group content of 3 to 35 meq/1 〇〇g, a 125 gsmi 6 吋 airlaid was prepared. pad. The carboxylated pulp may be present in a neutralized form or in a fully protonated (acid) form. Spray liner with Ep〇cr〇s WS5〇〇 and 1〇gm solution of polyacrylic acid (MW •• about 35〇〇) from Rohm & Haas, which is shown in the table below, 2Ep〇cr〇s and polyacrylic acid. (pAA) The desired amount. The EP 〇cros content varies from 3% to 7% by weight of the fiber, and the polyacrylic acid is maintained at 3% by weight of the fiber. The liner was dried and cured in a convection oven at i2 (rc) for 1 。 minutes. The wet tensile strength and dry tensile strength of the mat were then tested using a test device/system with vertical traction. For example, spray the pad with 10 gm of deionized water, let I21329.doc -10- 200809043 stand still for 10 minutes, and then test. From Table 3, the content of k#EP〇cr〇S is increased, and the dry tensile index is greatly increased. Add, and there is an optimum carboxyl content. It is also obvious that the tickified paper poly = form is more reactive 'to obtain higher tensile strength. The wet tensile index = like results are shown in Table 4. 'Table 3: Dry Tensile index, Nm/g

Table 4: Wet Tensile Index, Nm/g

Example 3: Ratio of EP 〇Cros WS5 〇〇 to polymaleic acid A 6 吋 airlaid liner modified to have a short (four) Mm (4) content of 21 meq/1()() g(d) was used. The carboxylated pulp can be used in a fully protonated (acid) form for the use of BP. (10) Cong 00 and / from Rohm & 121329.doc 200809043

Haas's polymaleic acid (MW: about 35 〇〇) of 1 〇 gm solution spray fun 彳 彳 到 到 到 到 E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E The Epocros content varies from 3% to 7% by weight of the fiber, and the polyglycolic acid is changed from 1% to 5% by weight of the fiber. The control liner contained only polymaleic acid. Place the liner at 12 inches. . It is dried in a convection oven and solidified in a knife. Next, the wet tensile strength and dry tensile strength of the liner were measured using a vertical traction 〇11 test device/system. For wet stretching, the liner was sprayed with 10 gm of deionized water, allowed to stand for 1 minute, and then tested. It can be seen from Table 5 that the strength value is increased due to an increase in the polymer content, and the dry stretching is increased by a large number. The data also showed that higher intensity values were obtained from the carboxylated paper κ & Similar results for the wet tensile index are shown in Table 6. Table 5 · Dry tensile index, Nm/g

121329.doc 200809043 Table 6 · Wet Tensile Index, Nm/g

P s is called a stagnation functional polymer. The specialty polymer backbone used in the examples herein is a polyacrylate copolymer. Except for the above methods, it is expected that other heating methods will promote the reaction. These methods are known to those skilled in the art. The heating temperature can range from approximately 6 degrees Celsius to 15 degrees Celsius. Curing for the process can occur via heating and/or pressure. While the embodiments of the present invention have been described and illustrated in the foregoing embodiments, many modifications may be made without departing from the spirit and scope of the invention. Therefore, the scope of the present invention is not limited by the disclosure of the embodiments. Instead, the invention should be determined with full reference to the scope of the following claims. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing a system for forming a covalent bond in an embodiment of the present invention; and FIG. 2 is a representation of an Epocros polymer in an embodiment of the present invention 121329.doc -13 - 200809043 [Main component symbol description] 12 Conveyor belt 14 Cellulose mat 16 Processing area 18 Dispenser 20 Dryer 22 Oven 121329.doc - 14

Claims (1)

200809043 X. Patent application scope: The method comprises the following steps: 1. A method for covalent bonding of cellulose networks: forming a net from a cellulose fiber of adenine; applying a crosslinking agent to the highly acidified Cellulose fibers to produce a treated web; and curing the treated web. 2. The method of claim 1, wherein the treated web is cured under heat, wherein the treated web is cured under pressure. The method of claim 1, wherein the fibers have a carboxyl group content of substantially greater than 7 meq/l 〇〇 g. 5. The method of claim 1, wherein the crosslinking agent is a mixture of an oxazoline functional polymer and a polyamic acid ester compound. The method of claim 1, wherein the crosslinking agent is applied in an amount ranging from about 8 kg to about 100 4 chemicals per pton of highly acidified cellulose fibers. The method of claim 5, wherein the polycarboxylate compound is applied in an amount of from about 8 kg to about 1 kg of chemical per ton of highly acidified cellulose fibers. 8. A cellulosic web comprising: a carboxylated cellulose fiber; a functional polymer; and 121329.doc 200809043 a poly-reductive acid material; wherein the functional polymer forms a crosslink with the polycarboxylate material And, in addition, one of the covalent bonds is formed between the highly carboxylated cellulose fibers and the crosslinking agent. 9. The cellulosic web of claim 8, wherein the functional polymer is a chewable polymer. I. The cellulosic web of claim 8, wherein the functional polymer is applied in an amount ranging from about 8 kg to about 100 kg of chemical per virgin cellulose. II. The cellulosic web of claim 8, wherein the polycarboxylate material is applied in an amount of from about 8 kg to about 1 〇〇 kg of chemical per ton of southern biochemical cellulose fibers. 12. The cellulosic web of claim 8, wherein the highly carboxylated cellulose fibers, the quasi-Wei basis, are substantially greater than 7 meq/i 〇〇 g. 121329.doc