JPS6035480B2 - Method of manufacturing paper containing starch fibers - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for manufacturing paper using water-insensitive starch fibers in place of all or part of cellulose pulp or other pulps conventionally used, and a process for manufacturing paper. relates to a method for blending functional additives into paper.

Various natural fibers other than cellulose as well as various synthetic fibers are used for paper manufacturing.

However, all of these new papermaking materials have not become commercially acceptable substitutes for cellulose for reasons such as cost, poor binding properties, lack of chemical affinity, and difficulty in handling in papermaking systems. On the other hand, attempts have already been made to use starch fibers at various stages of the papermaking process. However, attempts to use such starch fibers on a commercial scale have been unsuccessful. And even today, the majority of paper is made of wood-based cells. Currently, wood cellulose paper is manufactured from wood cellulose from beginning to end, and the supply of wood cellulose papermaking raw materials is rapidly becoming tight. As is well known, aqueous systems are usually used in the papermaking process, and therefore pulp fibers must have sufficient water insensitivity.
The fibers must maintain their integral shape over a relatively wide pH range at all stages of the manufacturing process.

In this regard, we would like to propose starch fibers as an alternative to cellulose fibers (see, for example, US Pat. No. 168
2293), but in order to provide the degree of water insensitivity required in the papermaking process, prior to forming fibers from starch, the starch is chemically modified to completely remove its original properties. It is necessary to change to. Other documents (e.g. U.S. Pat. No. 2,570,449
In the method described in No. 1, the papermaking method itself is changed to use starch fibers. That is, there is a need to replace the previously used aqueous systems with alcoholic solvent systems in which the starch fibers are not soluble. Clearly, the use of such technology is both impractical and uneconomical on a commercial basis. As a step in the papermaking process, it is often necessary to incorporate additives into the pulp to impart targeted properties.

That is, for example, pigments, latex, synthetic microspheres (m
Additives such as icrospheres, retardants, dyes, fragrances, etc. are increasingly used in paper making.

Effectively retaining these additives in the wet end of the paper machine is a difficult task for the papermaker, but is extremely important. The portion of the additive that is not retained and escapes not only represents an economic loss, but also poses a significant environmental pollution problem if it becomes part of the plant effluent. Additionally, such additives may be added through conventional coating or impregnating processes known in the art. Such a process usually consumes a large amount of thermal energy due to the redrying of the paper after its coating. In some cases, however, the coating has to be carried out reliant on solvents, which is extremely expensive and requires recovery of volatile substances. Accordingly, one object of the present invention is to provide a commercially acceptable method of using starch fibers as a partial or complete replacement for cellulose in conventional papermaking processes.

Another object is to provide a method by which additives can be effectively added to paper and retained during paper manufacturing.

Yet another object is to provide a method by which water-insoluble additives can be introduced into paper as encapsulated additives in the fibers.

The above and other objects of the invention will become clear from the description below.

According to the present invention, the above and related objects are achieved by converting insensitive starch fibers produced by precipitating colloidal dispersions of starch in pseudo-salt solutions into cellulosic fibers in conventional paper and board manufacturing processes. It has been discovered that this can be achieved by using similar fibers as partial or complete substitutes.

The starch fibers may be used to bulk up pulp, as a means of incorporating additives into paper products, as a binder to form fibers into non-woven webs, or for any combination of these purposes. sell. In this specification, "paper and paperboard" refers to cellulosic materials as well as fiber materials obtained from synthetic products (e.g. polyamides, polyesters, rayon, polyacrylic resins), mineral fibers (e.g. asbestos and glass) and other similar materials. Includes all sheet-like objects and molded articles made from

Furthermore, when we refer to "conventional papermaking processes" herein, we refer to wood cellulose fibers (which have been beaten or compacted to hydrate the fibers to a certain level and to which various functional additives may be added). The aqueous slurry is directed over a screen or similar device where the water is removed to form a consolidated sheet of fibers, which sheet formation is processed by compression and drying into the shape of a dry roll or sheet. means a process carried out in a manner that can form a sheet.

Furthermore, the above expression also includes within the meaning of the above expression the customary processes for the production of nonwoven products by wet or dry fiber laying. Accordingly, in one aspect, the present invention provides a viable, effective, and economical method for augmenting current raw material sources.

Additionally, the present invention provides paper manufacturers with greater flexibility in their operations. That is, paper manufacturers can obtain starch fibers in dry or wet slab form and store it for later use. Alternatively, a paper manufacturer may include its starch fiber manufacturing process as part of the pulp and/or paper manufacturing process.
It can be integrated into the plant as one process. Furthermore, the present invention provides paper manufacturers with a new means of adding additives to paper products with improved retention rates and thus in a manner with less economic loss and fewer contamination problems.

As mentioned above, it is common practice in the field of paper manufacturing to mix additives in relation to the type of fiber used in the pulp. Such additives are added to obtain special properties that cannot be obtained from the fiber itself. For example, additives that function as pigments (e.g., titanium dioxide) or for purposes such as improving gloss, opacity, smoothness, ink receptivity, flame retardance, water resistance, and increasing or decreasing bulk density are used in paper. It is blended into. In one embodiment of the present invention, when starch fibers are manufactured containing various functional additives and the fibers are then used in an aqueous papermaking process, the retention of the additives is less than that of conventional methods. It was found that this was significantly improved. In addition to improved retention, a further advantage of adding additives in this manner is that there is no need to worry about the charge balance between cellulose fiber additives and flocculants (e.g. alum) or other retention aids. That's true. In practice, the use of starch fibers according to the invention eliminates the need for flocculants or retention aids. Furthermore, it has been found that in accordance with the present invention, nonwoven webs can be produced in wet or dry form, with the starch fibers within the web acting as binders between the fibers.

In this case, the incorporated starch fibers can remain in the web of the final product or, depending on the desired end use, for example, the base fibers used in the web can be non-combustible. In some cases, starch fibers can also be removed. The present invention particularly involves introducing an aqueous slurry of fibrous pulp onto a screen where the water is removed to form a sheet of integrated fibers that is compressed and dried into a final paper product. This invention relates to improvements in the manufacturing process of paper and paperboard. The improvement thus provides a filamentous flow of a colloidal dispersion of starch at 5 to 4 wt. Forms of starch fibers 10 to 500 microns in diameter prepared by extrusion into a fluidized pseudo-coagulation bath consisting of an aqueous solution containing a coagulation salt selected from at least a sufficient amount to pseudo-precipitate the starch. 1 to 10% by weight of pulp in
It's about using it. The method of the present invention is easily applicable to all conventional paper manufacturing processes and can be adapted to the operations normally used in the equipment plant.

The only difference is that some or all of the cellulose pulp is replaced by starch fibers. The starch fibers used can be produced in various ways.

The only conditions are that the water-insensitive fibers should have a diameter of 10 to 500 microns and that the starch be prepared as a colloidal dispersion stream of 5 to 40% solids in a suitable flowing pseudo-salt solution. It is extruded and precipitated. Fibers made from any naturally occurring starch or fractionated starch can be used.

Namely, corn starch, waxy maize corn starch, rice, tapioca, wheat, and
High amylose corn starch, commercially available amylose powder, etc. can be used. Among these, naturally produced corn starch, corn starch, and waxy maize are preferred in view of their economic efficiency and ease of availability. The starch solids concentration in the dispersion should be about 5 to 4% by weight; higher concentrations can be used, but the resulting dispersion will be more viscous and special equipment will be required for its handling. .

However, the concentration used in the fraction will affect the properties of the final fiber and the desired end use. For example, starch fibers made from 5% solids dispersions are particularly useful in making glassine or oilproof papers, and starch fibers made from 15% solids dispersions are particularly useful in making porous papers such as oven paper. It has been found that it is suitable for The particular starch used must be used in the form of a colloidal dispersion. As used herein, the term "colloidal dispersion" refers to a dispersion of starch that is substantially free of grains and that exhibits little gelling or precipitation when left at the temperatures used. Dispersions in this state can be obtained using a variety of techniques depending on the particular type of starch base used, the end use and the equipment available. If a natural starch with a very high amylobectin content, such as waxy maize, is used, a suitable colloidal dispersion will be able to fully absorb the starch in water without any chemical additives or modification. cooking
It is possible to obtain only by

In most cases where starch with an amylobectin content of about 95% or less is used, the starch is chemically derivatized or modified to ensure a colloidal dispersion before addition to the aqueous system. desirable. This derivatization or modification may be carried out to the extent that it ensures the formation of the desired colloidal dispersion without affecting the ability of the starch to coagulate in the next step. Alternatively, if the presence of a caustic alkali in the system does not cause disadvantage A, the starch may be dispersed in an aqueous solution of sodium hydroxide, potassium hydroxide, or other commonly used alkalis. can. Still alternatively, the starch base can be dispersed in small amounts of organic solvents such as dimethyl sulfoxide and added to water, or using a combination of chemical additives such as urea and/or paraformaldehyde. . When carrying out the process by way of causticization, the amount of alkali used must be sufficient to sufficiently disperse the starch. Typical alkali usage when using sodium hydroxide is from 15 to 4% by weight, based on the weight of starch. When preparing a starch dispersion, starch is added to the dispersion medium.

It worships intensely until it becomes a state of dispersion. A dilute dispersion of starch (e.g. about 5-1% starch solids by weight)
), this takes about 4 minutes. In the case of more concentrated starch dispersions or certain chemically modified starch bases, longer and/or milder heating may be required. Most starch dispersions, including those obtained by boiling waxy maize, and most chemically modified starch dispersions, may be cooled to room temperature before being placed in the pseudo-analyzation chamber.

For the few types of starch with a low degree of chemical modification, the dispersion is used at approximately the same elevated temperature at which it was prepared to maintain its colloidal dispersion state and ensure effective fiber formation. It is preferable to do so. The coagulation bath used in the production of starch fibers used according to the invention contains a specific ammonium salt selected from the group consisting of ammonium sulfate, ammonium sulfamate, mono- or dibasic ammonium phosphate and mixtures thereof. Consists of an aqueous solution.

It is also possible to use the abovementioned ammonium salts in combination with other affinity salts which form starch precipitates and allow satisfactory pseudoprecipitates and textile products to be obtained. Suitable salts for this purpose include, in particular, ammonium peroxosulfate, ammonium carbonate, ammonium bromide, ammonium bisulfite, ammonium nitrate, ammonium nitrite, ammonium bicarbonate, ammonium oxalate, sodium and potassium chloride, sodium and potassium sulfate. It is. Generally speaking, the use of the additional salts described above provides no particular benefit since the ammonium sulfate, sulfamate or phosphate salts must each be present in a minimum amount to achieve the above-described pseudomorphisms. do not have. The only instances in which the presence of substantial amounts of other salts is desirable are when using recirculating pseudo-valleys in which on-site generated salts are present, as described below. The minimum concentration of salt required to carry out coagulation as well as the type of salt or salt mixture preferred will be determined by the type of starch base used. In the case of waxy maize starch, at least 3% ammonium sulfate is added to the total solution weight.
5% by weight, 72% by weight in ammonium sulfamate (
saturated), 37% by weight of dibasic ammonium phosphate and 4% by weight of monobasic ammonium IJ phosphate. Corn starch or amylobectin approx. 64-8
For similar starches containing 0%, the concentration of salts may be lower, such as 20% for ammonium sulfate, 50% for ammonium sulfamate, 25% for monobasic ammonium phosphate and 25% for dibasic ammonium phosphate. It can be used in an amount of 30%. Amylobectin content is approximately 5
For hybrid corn starches below 0%, at least 15% with ammonium sulfate, -40% with ammonium sulfamate and 2% with dibasic ammonium phosphate.
Requires the presence of 5% and 20% of monobasic ammonium phosphate. If a causticized starch dispersion is used, alkaline salts are generated in the pseudobath.

Satisfactory production of the desired starch fibers is sustained up to fairly high concentration levels of the salts generated. The acceptable critical level of salt generated above which fiber production becomes less efficient at concentration levels depends on the type of salt used, the total amount of salt solids used,
It will vary depending on factors such as the concentration of starch solids in the dispersion and the amount of amylobectin in the starch base.
Once an acceptable level of concentration of this salt is determined, in continuous mode the system can be constantly maintained at its maximum acceptable level (or below) by periodic additions of ammonium sulfate. For example, sodium sulfate is produced when sodium hydroxide is used as the dispersed soot and the starch mixture is extruded into an ammonium sulfate coagulation bath. In this case, the production of corn starch fibers (13% solids dispersion) was carried out using 3 ammonium sulfate in the bath.
Up to about 7 parts of sodium sulfate are present in Ikaribe's
It has been found to last satisfactorily until a 44% concentration solution is reached. Above this level of sodium sulfate, starch fiber production becomes less efficient and the produced fibers tend to lose their individual, integral shape. However, by adding small amounts of inorganic acids to the initial coagulation bath or to the bath during fiber production, the acceptable level of generated salts can be significantly reduced before fiber production in the system becomes seriously affected. It can be raised. For example, in the above example, by adding as little as 3 parts of sulfuric acid for every 10 parts of the initial coagulation bath salt charge, the acceptable level of sodium sulfate per 1 part of ammonium sulfate can be increased up to 9 parts of sulfuric acid. can be raised, and thus the life of the crystallization case is also extended. Of course, the salt solution can be recycled to the fiber forming process in which it is used and can be reused again once the fibers have been removed.

In this regard, starch dispersions that do not contain cathode lye pose little problem for recycling other than to reduce the solids concentration of the salt. However, if a causticized starch dispersion is used, a chemical reaction takes place with the coagulation solution. For example, if ammonium sulfate is used, the reaction results in ammonium gas and sodium sulfate. Recycling of such a system can be extended by recovering the ammonium in an acid scrapper and returning it to the system as ammonium sulfate. The sodium phosphate produced can be used in coagulation as part of the salt mixture until the above-mentioned acceptable levels are reached, and also as a raw material in pulp and paper manufacturing processes, e.g. in the production of kraft pulp. The so-called “salt cake”
Starch fibers can be made at any temperature that allows processing of the starch dispersion. Generally, pseudo-altcakes are prepared at about room temperature (altcake).
2000), but any higher temperature around 7000 can be used. Such high temperatures can be desirable under certain conditions because they increase the solubility of the salt in the coagulation bath, resulting in a more concentrated solution. Thus, for example, when attempting to produce waxy maize starch fibers using monobasic ammonium phosphate as a coagulant, it is desirable to increase the ambient temperature to obtain a subsalt concentration of about 40% (monobasic ammonium phosphate). Ammonium acid 20
The saturation level in °C is 28%). During the production of the starch fibers used according to the invention, the starch dispersion is introduced continuously or dropwise in the form of a thread into the fluid coagulating salt solution. This introduction can be carried out either from above or below the salt solution using conventional techniques. That is, the dispersion can be extruded through a device having at least one opening, for example using a spinneret, syringe or buret tube. Alternatively, the dispersion can be injected under pressure from a pipe or tube with multiple openings into a closed area around it, such as a homogeneous pipe containing a flowing coagulating solution. Various other related techniques can be applied and the fibers can be produced either batchwise or continuously. Whichever method is used, the aqueous salting out solution must be fluid when the starch dispersion is introduced. These two flow directions are used to control the fiber length and diameter or width. That is, when the salt solution flows co-currently with the starch dispersion, relatively rounded fibers are formed. Also, relatively flat fibers are formed when the starch dispersion is introduced at an angle of about 90 degrees to the flow direction of the salt solution. Open diameters of 10 to 500 microns are generally preferred for producing fibers of the size required for this invention. If the fibers are to be used as a replacement for cellulose pulp in paper, the starch fibers may be between 10 and 500 microns. The diameter (width) of the tube, and its length is usually 0.1 to 3.0
Let's be Willow. Longer fibers can be used in nonwoven web production. It will be appreciated that the length, cross-sectional size and shape of the fibers formed will vary depending on a number of interrelated parameters in addition to those mentioned above.

Additional factors to control the dimensions of the fibers formed, such as the viscosity of the starch dispersion, the body content and the type of ingredients used in the pseudo-lysis solution and/or the starch dispersion and their relative flow viscosities. It can be used in conjunction with the parameters listed above.
The above and similar pseudo-analytical methods for producing the starch fibers used in the present invention are disclosed in co-filed U.S. Pat.
No. 39699, the disclosure of which is incorporated herein by reference.

It is also described in US Pat. No. 2,902,336. Modifications of the above-described method may be used as long as the final fibers have sufficient water insensitivity for use in the papermaking process. The aqueous slurry or suspension of starch fibers can be introduced directly into the pulp stream.

This allows for the integrated or "in-line" production of fibers and paper webs within the papermaking plant. When this embodiment is adopted, it is generally preferable to first wash the fibers to remove the pseudosalts before entering the slurry into the papermaking process. Alternatively, the fibers can be recovered in dry form, for example by separating the fibers from the water and collecting them in a screen or similar device.

In this case, it is preferred to re-slurry the fibers in a non-aqueous solvent in which they are infusible, such as methanol, ethanol, isopropanol, acetone, etc. Thereafter, the fibers are recovered from the solvent, for example by filtration, and dried. Alternatively, centrifugation, flash drying or spray drying, etc. can be used to remove water. After drying, the fibers can be reintroduced into an aqueous medium and will exhibit excellent redispersibility while maintaining their discrete, discrete, individual fiber structure. Fibers can also be recovered from the slurry, such as by filtration, washed and dispersed in water to a level of about 50% solids to form wet "wetslabs" for subsequent use. The starch used in this invention may be chemically treated to alter the properties of the fibers produced or to aid in the rapid formation of colloidal dispersions. Alternatively, after being formed into fibers, the starch fibers can be treated to impart certain functional properties. That is, chemical treatments such as aminoethylation can be applied to the starch in order to speed up the dispersion rate of the starch. This process also serves to produce fibers that have a cationic charge when used in aqueous media. Similarly, starches modified to contain anionic groups may also be used. Such modified starches are stable in dispersion and fibers with anionic properties are produced. Furthermore, treatments can be carried out after fiber formation to modify them in order to impart special functional properties. For example, improved anionic functionality can be obtained by bleaching the fibers after precipitation, as long as the conditions do not adversely affect the fibers. The properties of the fibers can be further controlled by blending several types of starch, modified or unmodified, or by adding other functional substances, such as polyacrylic acid, thereby making it possible to obtain specially desired characteristics can be obtained. One of the advantages of the method of the present invention is that it provides a means to improve paper products in various ways due to properties inherent in, or which can be imparted to, the starch fibers themselves.

An example of such improved properties is the production of various specialty papers such as glassine and furnace papers, which require special treatment when produced by conventional methods. Glassine paper is made from pulp of a quality that allows the fibers to be highly hydrated.

This paper owes its remarkable grease resistance to the mechanical treatment done to the pulp while suspended in water. The fibers are fibrillated and swollen to almost a gel-like state.
When paper is made from the hydrated fibers, a compact, non-porous sheet is formed over the wire. The formed sheet is impermeable to oils and fats because it is composed of nearly continuous, well-hydrated cellulose. A large amount of energy is required to obtain cellulose in such a well-hydrated form. Glassine manufacturers must subject their raw material to a lengthy refining process, which increases the number of refiners through which the raw material must pass. After the raw material is hydrated, it is introduced into a wire and dehydrated, but this dehydration proceeds very slowly. As a result, machine speeds are limited to 150-50 rpm depending on the basis weight of the paper being produced. In order to promote dehydration on the wire, the temperature of the raw material may be increased with steam. Attempts have been made by glassine manufacturers to use cationic polyelectrolytes to improve dehydration, but success remains limited. Fiber agglomeration can improve dewatering, but it can disrupt the formation, create pinholes, and reduce the oil and grease properties of the product. The inventors have now discovered that when starch fibers are combined with cellulose fibers that have been refined to a lower degree than is required for conventional glassine production,
It has been discovered that the mixture has a very high freeness and is dehydrated at low temperatures in about one third of the time required by conventional high temperature dewatering.
Furthermore, compared to glassine raw materials, the compressed wet mat is more solid and has excellent drying efficiency. Furthermore, the new paper sheet has greater internal strength (Z-direction strength), improved oil resistance, and greater resistance to air permeation than conventional glassine paper.
It is clear that the refining process of cellulose results in considerable energy savings. This is because the fiber blends of the present invention do not require high temperatures to dehydrate to acceptable levels as is done in conventional glassine production. Starch fibers may also be used to provide more porous sheets.

This property is desirable in paper applications such as oven paper and impregnated base paper. In conventional methods, it is known that lighter refining of cellulose helps to impart these properties. However, this was done at the risk of reducing the strength of the web.
According to the present invention, by blending starch fibers in combination with cellulose, while maintaining the required strength properties,
Alternatively, sheets with a more porous structure can be obtained, often improving it. As a further feature of the present invention, certain hydrocolloids may be extruded with starch into the starch dispersed soot to produce starch hydrocolloid fibers that can be used in the papermaking process of the present invention.

To obtain such a fiber composition, all that is required is to add a hydrocolloid (50% of the total solids weight) prior to contact with the coagulant.
All that is required is to place the following amounts together with starch in a colloidal dispersion state. Therefore, polyvinyl alcohol
In the case of water-dispersible hydrocolloids such as starch, carboxymethyl cellulose, and hydroxyethyl cellulose, it is sufficient to simply add the hydrocolloid to the water in which the starch is dispersed. For other hydrocolloids, such as casein, it may be necessary to caseify the dispersion to form the required colloidal dispersion. In another embodiment of the present invention, water immiserable additives can be mixed evenly throughout the starch dispersion and incorporated in the resulting starch fibers in encapsulated form.

In this way, pigments, metal powders, latex, oils, plasticizers, microspheres (glass beads, expanded silica or other low density materials in expanded or unexpanded form) etc. can be incorporated into the starch fibers according to the invention. I can do it. Similarly, water bathable synthetic polymers or latexes such as polyvinyl acetate, polyacrylonitrile, polystyrene, etc. can be incorporated into the fibers. Furthermore, the density of the starch fibers can be varied by blowing air or other gas into the starch dispersion before it passes through the coagulation grid. Additionally, certain water-soluble solid additives may be co-extruded with the starch fibers.

In such cases, the additive is dissolved in the starch dispersion and the coagulant used to form the starch fibers is adjusted by adding a sufficient amount of an affinity salt capable of precipitating the additive. . For example, a starch-aluminum rosin co-precipitated by adding a commercially available rosin size to a starch dispersion and extruding it into a coagulation bath containing a starch coagulation salt with a sufficient amount of aluminum sulfate to precipitate the rosin. - It is possible to form fibers. The water insolubility of the starch fibers in the present invention is further enhanced by the use of conventional crosslinking agents such as urea-formaldehyde, glyoxade, urea-melamine-formaldehyde, kMmene.
Hercules Corporation of Wilmington, Delaware, USA (
Herculesgnc. ) registered trademark].

These crosslinking agents may be added to the starch dispersion before extrusion or may be added to the starch fibers afterwards. The type of additives added as well as the amount thereof will be determined by the desired properties of the final fiber.

For example, pigmented fibers exhibit improved opacity and can be incorporated into fiber webs by conventional methods. In this case, the overall pigment retention is improved compared to simply adding pigment to a conventional paper stock system.
Flame retardancy can be imparted to the starch fibers by adding polyvinyl chloride powder, antimony trioxide or other flame retardants. It is also possible to incorporate microsphere-containing starch fibers into paper webs at high retention rates. By adding such microspheres, it is possible to produce a sheet that is larger in height and weighs 4.5 mm compared to the corresponding cellulose sheet. In the case of conventional sheets containing micro-4 spheres, the presence of micro-spheres between the fibers weakened the bond between the fibers, resulting in a decrease in the strength of the sheet. In comparison, the sheets of the present invention have superior strength. This is because the microspheres are encapsulated within the starch fibers and their weakening effect on fiber bonds is reduced. The density of the starch fibers, and thus of the paper produced, can also be varied by blowing air or other gases into the starch dispersion before it passes through the coagulation bed. What's more,
By using fibers encapsulating additives, it is not only possible to provide a new method of incorporating additives into paper, but also to provide new effects to the paper itself.

For example, papermaking machines exist for producing final web products made up of several individual layers compressed together. Such devices are, for example, round bar paper machines or long paper machines with a downstream second headbox or several headboxes. These types of paper machines typically use lower quality fibers for the inner layer and relatively better quality pulp for the surface layer or topliner. The use of pigmented starch fibers in this topliner allows the production of paper webs with the surface properties of coated paperboard. In practice, coated paperboards are manufactured using wet-endapplication processes due to the high concentration of starch and dyes on the surface of the substrate.
rocess). Alternatively, special decorative or imitation papers could be produced with different colors on both sides. Dyed fibers can be prepared in separate colors and fed into two different headboxes.
Such double-sided colored papers are still made today, but require the addition of color to the surface during processing. One of the advantages obtained using water-insoluble synthetic polymers encapsulated within starch fibers is that of synthetic fibers such as rayon, acrylic, polyester, nylon or polyp.

pyrene) in paper and paper-like webs. Most of these fibers have very low surface charge, and therefore, latex binder systems are commonly used and retention is achieved through precipitation and fiber deposition techniques, but their retention is poor. Because of this poor retention, the binder efficiency is low and problems such as foaming, adhesion, and deposition of the polymer may occur within the system. The resin-loaded starch fibers according to the invention ensure effective retention and impart the desired properties to the final sheet. Additionally, the starch fibers obtained in connection with the process of the invention can also be used for the production of non-woven products made by dry laying of synthetic fibers.

For such applications, a nonwoven web is formed using air as the medium for placing the fibers onto a moving wire. Because synthetic fibers are not hydrated, they are not bonded and produce relatively weak, soft structures. therefore,
It is necessary to spray a bonding agent onto the web surface to impart integrity to the web. According to this method,
It is possible to incorporate dry protein fibers into synthetic fibers. Such a method is particularly advantageous in the field of disposable nonwoven products. This is because the biodegradable properties of starch fibers are far superior to currently used synthetic fiber binders. Starch fibers used as such a binder preferably have a particularly high content of amylobectin. The starch fibers can remain in the final nonwoven web product or can be removed from it if desired. For example, when it is desired to remove starch fibers from a ceramic web, the starch fibers can be conveniently removed by subjecting the web to ashing conditions sufficient to burn out the starch fibers. Starch fibers can be used alone or in combination with cellulosic or non-cellulosic fibers of any type for the production of fully starched paper products.

Softwood or hardwood cellulose fibers that can be used include bleached and unbleached sulfate pulp (kraft pulp), bleached and unbleached sulfite pulp, bleached and unbleached soda pulp, neutral sulfite pulp, semi-chemical groundwood pulp, chemical groundwood pulp. Includes individual fibers and combinations of these fibers.

These fibers are wood pulp fibers produced by various methods conventionally used in the pulp and paper industry. Furthermore, synthetic cellulose fibers belonging to viscose rayon or regenerated cellulose as well as waste paper recycled from various sources can also be used. Similarly, ceramic fibers, glass, asbestos or other inorganic fiber materials can also be used in combination with the starch fibers of the present invention. Because of the water-insensitive nature of the starch fibers used in accordance with the present invention, the fibers readily disperse and become stable dispersions that can be used in conventional papermaking processes without the need for the addition of surfactants.

This allows the fibers to be passed through the papermaking process and papermaking machine without any changes to the normal manufacturing conditions. That is, the fibers can be added to the beater or compounding chest, enter the headbox and be guided to the screen of the liner paper machine and from there conveyed in sheets to the wet press process, passed through dryer rolls, calenders, etc. It is then rolled up into sheets. This means that there is no need to make any changes to the conventional operating characteristics of the machine for producing cellulose paper. In cases where paper is made entirely from starch fibers, it is desirable to place the web between nylon mesh screens and to wipe the web dryer better than in the conventional case to prevent fibers from sticking to the dryer. Furthermore, by using a slurry containing as-precipitated fibers, the papermaking process and the starch fiber manufacturing process can be integrated. It is also possible to produce molded articles directly from a dense fiber slurry by slush molding in a master or mold. As will be appreciated by those skilled in the art, the type of starch and amount of starch fiber used will vary depending on the desired paper quality.

It has now been found that by selecting the appropriate type of starch, preselected sheet properties can be obtained simply by hydrating and fibrillating the wood pulp to various degrees of freeness. More specifically, the use of unbleached kraft linerboard requires light refining of the pulp (650', CSF) to ensure rapid dewatering while maintaining high processing rates. Ta. The degree of refining, in turn, affects the internal fiber bond strength of the manufactured product. The introduction of starch fibers allows rapid dewatering and maintenance of high production rates, while also guaranteeing internal bond strength. Glassine paper is mostly made from highly refined (less than 50 sakaki, CSF) pulp. The inventors have found that by adding 15% starch fiber and any smaller amount, an equivalent glassine paper can be produced with half the refining process. Alternatively, in the case of papers requiring low opacity and porosity, it is preferred to use higher amounts of starch fiber, such as about 50% or more.
The starch fiber-containing papers of this invention can be prepared with any commonly used internal additives such as size, wet or dry strength additives.

Furthermore, the surface can be treated by conventional means such as coating, spraying or impregnation. The starch fiber-containing paper of the present invention can be repulped and reused.

The ability of starch fibers to retain their fiber integrity during repulping depends on the type of starch fiber (starch with a high amylose content is easier to repulp) and its It depends on the repulping conditions to which it is subjected. Generally speaking, the lower the degree of use of basic agents and the use of high temperatures, the more favorable it is for recycle use of the starch fibers. Examples of the present invention are described below.

In the examples, all "parts" are parts by weight unless otherwise specified. Note that Example 13 is shown for reference. Example
1. A naturally occurring unmodified starch consisting of 70% amylose and 30% amylobectin is mixed in water to a concentration of 5% solids by weight, and then a 25% solution of sodium hydroxide is added to the dry starch weight while stirring. A slurry was prepared by adding it to 40% causticity based on the standard.

This mixture was stirred until a starch dispersion was obtained.
The resulting dispersion was extruded through a spinneret at a pressure of 703 mm into a pseudo-analysis bath.

The coagulant used consisted of a solution of 28% solid ammonium sulfate and the paper tip had an open ION sphere of 70.2 microns in diameter. The dispersion was extruded at a 900 angle to the moving salt solution. The resulting fibers were collected on a wire mesh screen, the salt washed out and collected again. The fibers had an average diameter of 65 microns, an average fiber length of about 4 sides, and a final solids content of 23.5% by weight. Noble and Wood
A large number of handmade test sheets were made using an unbleached hardwood pulp (spotted WK) in combination with the fibers produced above using a paper machine (DWood) at various blending ratios.

These sheets can be dried in a noble and dryer for 12 minutes.
It was dried at a drum temperature of 1°C. and after that 220
Conditioning was performed by leaving the sample for 2 hours at a constant temperature of 55% and relative humidity of 55%. The sheet manufacturing conditions and test results are as shown in Table 1.

Table 1 [Note] {1) Measurement of the amount of water dewatered from the pulp through the wire screen.

Unbeaten pulp is good (beaten pulp is good) The water level will be higher compared to the previous year.

TAPPI Test Method T227-M-58.

(Test 2 measures the air permeation resistance of paper.

The volume of air passing through a fixed sample area at a given pressure and time is measured.

The higher the measured value, the more porous the sheet is (7.
62c 1. D. Ring used; measurements without units).

{3' Scot Internal Bond Tester (Scot
The strength of the paper sheet in the Z-direction is measured using an InternaBond Tester.

This test method requires The force (joules) per square meter This is to find the average.

TAPPI RC-305.

The results shown in the table show that as the amount of specific starch fibers made in a 5% solids dispersion increases, the water retention of the fiber formulation improves compared to that of a 100% cellulose sheet. It is shown that sheets with lower porosity and greater Z-unidirectional strength are produced.

Example 2 Starch fibers were produced using the materials and methods used in Example 1.

However, this time, after the final water wash, the fibers were dispersed in an ethanol solution, bottled, and left to dry.
Cell this fiber. A test sheet was prepared by blending with a base and hand-rolling the same as in Example 1. Test results of these handmade sheets showed that the dry fibers provided performance characteristics comparable to the wet fiber product of Example 1. Example
3 Starch fibers were produced using the same materials and methods as in Example 1.

However, this time, the starch solid concentration of the starch dispersion was 20
% and the final solids level of the fiber was 38%. Handmade sheets were made and tested as in Example 1. The test results are shown in Table 01. Table 0' As shown, the use of starch fibers made from dispersions with high collective concentration levels results in higher water release (i.e., freeness) of the product and compared to sheets of 100% cellulose. Also, a sheet with high porosity and high Z-direction strength can be obtained.

It is noteworthy that the dryness and porosity values of the sheet obtained at this starch concentration show a clear contrast with those of Example 1, where a dispersion at a level of 5% starch solids was used. It is that you are. A comparison of the results in Tables 1 and 2 shows that the method of the present invention can be adapted to impart various properties to the final product (for example, the porosity required for glassine paper or, conversely, the porosity required for filter paper). I understand. Furthermore, it is noted that in both Examples 1 and 3, the strength of the paper is improved by the use of starch fibers. Example 4 Starch fibers were produced in the same manner as in Example 3 using a 20% solid starch dispersion.

However, this time, after washing, the fibers were reslurried in ethanol, collected, and dried. Handmade sheets were made and tested and it was found that the dry Akonno fibers provided performance comparable to the results obtained using the wet fiber product of Example 3. Example 5 This example illustrates the use of fibers formed from various starch bases in the production of paper according to the invention.

The production of starch fibers and the blending of cellulose were carried out according to the method of *Example 1.

The cellulose part is Canadian
It was beaten before compounding by 645'. The basis weight of all handmade sheets is 97.
．． It was maintained at 5 pm/m. Table m [Note] (1) TAP
PI Test Method T404-5s - Measurement of tensile shear strength at 66 pounds/inch (converted to metric).

'2) TAPPI test method T403-ts-63 diameter 3
When pressure is applied at a controlled rate of increase to a circular castle made of 048 material through a rubber membrane, the hydrostatic pressure in Bondnoinch (converted to metric system) required for the paper to rupture is measured.

(31 As described in Example 1.

(4) TAPPI test method T423M-50 This is the number of bends that a test piece can withstand until it breaks.
ssetslnstitnte ofTechnolo
A bending tester developed by gy is used.

Example 6 This example illustrates two methods for producing sheets of 100% starch fiber.

[Method A]

Six pieces of unmodified corn starch fiber were slurried in water.

It was simulated with a webbed fly trick until a homogeneous mixture was obtained.
Handmade sheets were made using a Noble and Wood handmade machine equipped with a 100 mesh wire screen.

The formed fibrous web was removed from the screen and blotting paper and subjected to a series of presses as described below. While changing the blotting paper, press 7030/8 evening/Mede 3 presses and 281
hey. 2nd evening / 3rd press. During this time, the web was placed between blotter papers and dried in a Noble Undoo dryer at a temperature of 120.1°C. The resulting rigid, self-supporting paper product had a basis weight of 145 kg/force. 〔Method
B] The starch fibers were treated as described in Method A and the resulting web mat was pressed in the following order: changing the blotting paper for each pressing operation and so that a wet mat of 50% solids was formed; 7030.89/second press and 14061.6 ta'c second press.

After this the web is placed between two natron wire screens and 120. It was dried by passing it through a no full and wood dryer on ro. The basis weight of the resulting rigid, self-supporting paper web was 145 m/m. Example 7 A handmade sheet was made according to the method of Example.

However, this time, commercially available unmodified refined glassine raw materials with two types of low water content were combined with corn starch fiber. The cellulose pulp used was collected from two locations during the refining process. In other words, one location is the ShopperRie Glaro water level (ShopperRie
glerfreeness) is 350', the other one is fully refined above the low water level of 160'. Up to 20% of cellulose fibers are replaced with starch fibers and all have a basis weight of 48.8%/
I made a handmade sheet. Next, the sheet was subjected to surface sizing treatment using a laboratory size press equipped with rubber rolls. This includes a 1% polyvinyl acetate solution [AirProd under the trade name Vinol 165].
ucto and Chemicals, Inc.] was used, the temperature was 6000°C, and a 1% pick-up of polypynylacetate was achieved. The sheets were then conditioned for 24 hours at a constant temperature of 2000 and room temperature of 55%. Afterwards T
Terventine resistance testing was performed using APPI standard test method T454-t's-66.

The results of the terbentine test were as shown in Table W. Table W *Sold by Terting Networks, Inc.

Shopper-Riegler Freeness
Measured by Tester.

By using starch fibers in combination with a partially refined pulp, the terbentin resistance of the pulp alone was increased and was comparable to that of a fully refined glassine stock.

Furthermore, by reducing the refining process, the dewatering time can be reduced by almost one-third at much lower temperatures. In other words, as seen in the table, to achieve the dehydration time of 62 sand with conventional raw materials, it is necessary to raise the temperature to about 6,000 °C, whereas with the starch fiber blend, it is necessary to raise the temperature to about 2.
A dewatering time of approximately 2 silica sands at a temperature of 40° C. is achieved without any loss of desired properties due to the use of the method of the invention. This improved dewatering allows for higher machine speeds and higher production rates, while reducing refining operations and lowering feed temperatures, resulting in significant energy savings. Example 8 This example demonstrates the property improvements obtained by incorporating starch fibers containing polymeric microspheres into cellulose pulp.

Starch fibers were produced according to the method of Example 1, but
However, this time, prior to fiber formation, 8.
5% microspheres (DowChemic as XD6850)
(obtained from Al Co., Ltd.) was mixed.

Then, according to the method of Example 1, the fibers were blended with cellulose wood pulp to make a handmade sheet. In both cases, the value of water level (Canadian standard) is cell. The carbonaceous component was 730M. The results of the test are shown in Table V. For comparison, test results are also shown for samples made by adding microspheres directly to paper pulp using methods conventional in the art. Table V [Note] (1) Thickness of paper expressed in quarter centimeter o■
TAPPI test method T451-M-60 (3) Example 1
As shown in Table V, the thickness and stiffness of the paper product was substantially improved by the addition of microspheres by either method.

That is, by adding microspheres, only 97.6
It was possible to obtain the same thickness and stiffness as at that time with a basis weight of 130 Yu. It will be readily appreciated that this weight savings helps reduce the amount of pulp required and associated costs (eg, postage) after paper production. Comparison of other properties obtained from sheets containing micro-4 spheres reveals the following.

That is, the retention rate for externally added spheres is about 50% of the initially added amount, while for spheres added encapsulated in the fibers, the retention rate is about 100%.
Furthermore, a decrease in strength and an inhomogeneous distribution of spheres (higher density on the felt side) are evident in the case of externally added spheres, whereas in the case of spheres added encapsulated in starch, In some cases, such factors do not exist at all. Therefore, the increases in thickness and stiffness obtained by the external addition of conventional spheres are only obtained at the expense of reducing the internal bond strength of the paper. In contrast, incorporating the balls within the starch weave ensures retention of the balls in the sheet, yet adds the desired stiffness and thickness, as well as increasing internal bond strength. Example 9 This example shows the results obtained using three methods of adding clay in the papermaking process.

A handmade sheet was produced in the same manner as in Example 1.
No. 1 is added to the final sheet while the hand-made sheet is being formed. 2 coating grade clay was added.
The addition of clay to handsheets was done in three ways: 1. Adding the pigment to the pulp fibers as conventional.

2 Add starch fibers made according to Example 1 but containing 80% clay and 20% starch.

3 By a combination of m and method {2).

In either case, the basis weight of the sheet was 97.6 m/m.

The physical and optical properties of the paper sheet obtained were as shown in the table.

front [Western] '1) TAPPI test method T425 Ichihada-60.

The diffuse reflectance is measured by backing the test with a white plate with an absolute reflectance of 0.89 and a black plate with a reflectance of 0.005 or less, and the ratio of the latter to the former is multiplied by 100. The higher the number, the greater the opacity of the paper. (2) As described in Example 5.

(3) As described in Example 1.

As can be seen in the table, when pigments are incorporated into starch fibers, large pigment loads are possible and the strength is also increased compared to conventional pigment loading techniques.

That is, when 12.8% clay was added to cellulose pulp using the prior art, the tensile strength and Z unidirectional strength decreased. On the other hand, when 19.8% (total addition amount: 24.8%) of clay was added in the form of starch fibers containing clay encapsulated therein, the tensile strength and Z unidirectional strength were improved. Furthermore, it has been found that the reduction in opacity caused by using clay-containing fibers can be compensated for by externally adding small amounts of clay or titanium dioxide. Example 10 This example demonstrates the excellent retention capacity of starch fibers used by the method of the invention.

Bleached hardwood kraft pulp was beaten to a low water content of 500 bars (Canadian standard) and divided into three parts.

One of the portions contains No. Two coating grade clays were added and the formulation was stirred until the pigmented clay was evenly distributed throughout the pulp fibers. The second part contains Natron 86 as a retention aid.
86) [NationalSnerchandChemi
calCorporation trademark] was added.
In other respects, the process was the same as above. To the third portion of pulp, starch fibers (50% starch and 50% clay) containing clay encapsulated therein are added and this fiber blend is stirred until a homogeneous dispersion is obtained. I worshiped it. A handmade sheet was prepared in the same manner as in Example 1, and its clay content and retention rate (percentage) were measured. The results were as shown on the surface skin. As can be seen from Table W above, clay retention was highest when the clay was incorporated into starch fibers according to the present invention.

Example 11 This example demonstrates the bonding properties of starch fibers in the production of multilayer sheets.

Two-ply handsheets were made on Noble and Wood handsheet equipment from bleached hardwood kraft pulp beaten to a 500' water content (Canadian standard).

Two layer sheets (
They were pressed together when wet and then dried in a Noble and Wood dryer at 12100. One control handmade sheet had 100% cellulose in both layers, and the other test sheet according to the invention had 20% of the cellulose in the upper layer replaced by starch fibers. The bonding force between both layers is calculated on Scot In
The internal bond was tested using ster.
The results were as shown on the front side. Top plate (Note 1) As described in Example 1.

As shown on the front side, the presence of starch fibers clearly increased the bonding strength between both layers of the final sheet.

EXAMPLE 12 This example illustrates the production of additive-loaded paper by adding starch fibers containing encapsulated additives.

Similar to Example 8, additives are incorporated within the starch fibers and used to make handsheets containing the starch fibers at predetermined percentages as shown in the table below.

Table of Contents [Note] mNatio Side I Starch and Ch
Registered trademark of sizing agent available from chemical Corporation [2-Hercmespowde]
In all cases of the Zizing Agent® trademarks available from rCo, the additives were retained at high levels in the final paper product and imparted the respective additive properties to the product.

Example 13 This example illustrates the use of starch fibers as a means to add a latex binder to a nonwoven web of synthetic fibers.

Dispersions of fibers (0.635 1.5 denier) and polyester fibers (0.635 denier, 1.5 denier) were prepared at 0.1% concentrations in separate containers.

Starch fibers containing 100% starch fibers and 20% by weight latex, vinyl acetate/butyl acrylate copolymer were added as binders in amounts such that the final fiber formulation contained 25% starch fibers. A handmade sheet having a basis weight of 65 mm was made using a Noble & Wood handmade machine in the same manner as in Example 1. A tensile test was conducted on these handmade sheet webs to determine the degree of improvement in tensile strength. The results were as shown in Table X below. Table × *The sheet did not have sufficient integrity for tensile testing.

(Note 1) As described in Example 5.

As seen in Table X, the webs made using starch fibers and starch-latex fibers as binders had excellent tensile strength.

In contrast, the control web made from 100% synthetic fibers did not even have enough integrity to handle for testing. It is noted that the latex used increases the tensile strength of the web, but reduces the strength of the polyester web compared to 100% starch fibers. This shows that it is necessary to select an appropriate latex for the processing of synthetic fibers. Example 14 This example illustrates the use of starch fibers as a binder for ceramic fibers.

Additionally, this example shows that it is possible to remove the starch fiber binder after web formation to produce a 100% ceramic fiber sheet. 3% concentration ceramic fiber slurry in a Waring Blender
NaOHO. 2%
(based on the dry weight of the fibers) was added and allowed to simmer for 1 minute.

This fiber dispersion was then transferred to a vessel equipped with a water paddle sludge and starch fibers were added to the desired amount as a 1% strength dispersion. After mixing this formulation for 5 minutes, handsheets having a basis weight of 407 mm/m were made on a Noble and Wood handsheet machine.

As a control, a ceramic sheet was made without any starch fibers added. Strength tests were conducted using all of these sheets.

The results were as shown in the figure. Hyotegen Desobu Fiber Basis Weight (9/2) Order>So2) 0
407.5 *5 many 40
7.5 3.521○ Poor 407-5
It did not have the integrity to withstand the 20-39* test.

(Note 1) As described in Example 5. The sheet containing the starch fibers was then placed in a kiln maintained at a temperature sufficient to incinerate the starch fibers and fuse the ceramic fibers.

A well bonded ceramic web is thereby produced. Example 15 Ti0210 with final sheet basis weight of approximately 1459/m
A two-layer handmade sheet containing %.

In the control sheet, Ti02 was added in a conventional manner by dispersing the pigment with the unbleached kraft fibers that served as the top liner. To the remaining handsheet, 20% by weight Ti02 loaded starch fibers were added in an amount sufficient to give the top liner 10% Tj02 based on the final sheet weight. The final sheet consists of two layers, each layer made separately on a Noble-and-Wood hand-sheeting machine with a basis weight of approximately 72.5 mm/cm, removed from the wire and crimped together to form a sheet of 14,061.6 mm/cm. The ground was reduced to a wet mat.

Next, use Noble and Wood Dryer to 1210
Dry at a temperature of 0. TAPPI test method R-45
The whiteness was measured on the top liner side according to 2-M-58. The results are shown on the table. Table Blood sample sheet Top liner brightness control
26.2 Starch fiber
The results presented in Section 30.1 show that handmade sheets made using Ti02-encapsulated starch fibers have superior properties than those made using conventional methods.

Although the present invention has been described above in detail with reference to preferred embodiments, the present invention is not limited only to these embodiments.

Claims (1)

Claims: 1. An aqueous slurry of fibrous pulp is introduced onto a screen to remove water, thereby forming an integrated sheet of fibers, which is compressed and dried to form the final paper. In a process for manufacturing paper and paperboard, the process of manufacturing paper and paperboard comprises using starch in the form of water-insensitive starch fibers of 10 to 500 microns in diameter in an amount of 1 to 10% by weight of the pulp, the starch fibers having a solid ~40% by weight
A coagulating salt selected from the group consisting of ammonium sulfate, ammonium sulfamate, monobasic ammonium phosphate, dibasic ammonium phosphate, and mixtures thereof is applied to at least the above starch. A process as described above, characterized in that it is produced by extrusion into a fluidized coagulation bath consisting of an aqueous solution containing an amount sufficient to effect coagulation. 2. Process according to claim 1, characterized in that the starch fibers are produced from corn starch or waxy men's starch. 3. The method of claim 1, wherein the starch fibers are made from high amylose starch. 4. Process according to claim 1, characterized in that the starch fibers are produced from cationically derived starch. 5. Process according to claim 1 or 4, characterized in that the starch fibers are produced from ether or ester derivatives of starch. 6. Claims 1 to 5, characterized in that the colloidal dispersion of starch further comprises a dispersed water-insoluble additive replacing the starch in an amount of up to 80% by weight.
The method described in any one of paragraphs. 7. According to any one of claims 1 to 6, the colloidal dispersion of starch additionally comprises dispersed hydrocolloids in an amount of up to 50% by weight of the starch. the method of. 8. A method according to any one of claims 1 to 7, characterized in that the starch fibers have a length of 0.1 to 3.0 mm. 9. A method according to any one of claims 1 to 8, characterized in that the other fibrous pulp is substantially in the form of wood cellulose. 10. Claims 1 to 10, characterized in that the other fibrous pulp is substantially in the form of fibers selected from the group consisting of polyester fibers, rayon fibers, ceramic fibers, glass fibers, and asbestos fibers. The method according to any one of paragraph 8. 11. Thoroughly dispersing at least one water-insoluble additive in a colloidal dispersion of 5 to 40% solids fibers;
The filamentous flow of the dispersion is caused to coagulate at least the starch with a coagulating salt selected from the group consisting of ammonium sulfate, ammonium sulfamate, monobasic ammonium phosphate, dibasic ammonium phosphate, and mixtures thereof. The dispersion is precipitated by extrusion into a fluidized coagulation bath consisting of an aqueous solution containing a sufficient amount of 10 to 500 mm diameter particles in which the additive is enclosed and contained. Forms micron water-insensitive starch fibers,
A method for incorporating water-insoluble additives in conventional papermaking pulp systems, characterized in that the formed starch fibers are then used as a component in the papermaking pulp system in an amount of 1 to 100% by weight of the pulp.