JPS60173200A - Production of soft paper web - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] This invention relates to a method for preparing a soft, light-textured paper queso having a texture.

Examples of sanitary paper products that can be made from these types of webs include restroom tissues, facial tissues, paper towels,
and napkins.

The durable strength of paper webs formed from aqueous slurries of cellulose fibers results from the interfiber bonds formed by the hydrogen bonding processes associated with #paper. Papers with a substantial collection of these bonds are characterized by both strength and stiffness.

Softness is the most desirable characteristic of sanitary paper products. In order to achieve a comfortable degree of softness, the strength of the web is reduced, either mechanically or chemically, to break up and reduce the filamentous bonds in the paper web that form during drying. To achieve this, the web is creped from the dry side with a creping blade, a chemical loosening agent is applied to the fibers forming the web, and the web is A number of proposals have been made for circumferential laser processing.The combination of these methods results in relatively low strength levels for a given degree of improved softness.

Seven attempts have been made to improve the spreadability of sheets after creping. These included preferential creping techniques using notched creping blades or discontinuous creping. The sheets produced in this manner were shown to have low tensile areas. In another proposal, the interfiber bonds formed during the drying of the queso were supplemented with chemical bonds before creping, resulting in a stronger sheet with the desired softness, but with I was able to get to one song very well. In another proposal, pressing the sheet onto a drying cylinder with a fabric provided differential adhesion to the creped surface to reduce strength loss. As a result, only a portion of the sheet is affected by the creping blade. In this case, differential adhesion necessarily reduces the overall adhesion of the sheet to the creped surface, resulting in a lower overall creping response and less softness gain.

Compression promotes the formation of interfiber bonds when the web is being made, and the solution for successful soft paper production is to avoid mechanical densification of the wet web at any stage during web production. was to prevent the formation of these bonds. Drying of the web is accomplished by using through dryers that direct the air through the web,
It has been found that the internal structure of such uncompressed webs has an inherent bulk and softness that derives maximum benefit from the subsequent creping process. Consumer demand for even softer sanitary paper products has made it difficult to achieve the required softness from traditional soft paper manufacturing equipment of the type that compresses the web, removes the water, and then crepes from the surface of a Yankee dryer. It is important to make paper with paper.
Although good results have been obtained using through-dryer technology, such equipment is very expensive both to install and operate. There has been a substantial need for a soft paper manufacturing process that can utilize conventional Yankee paper machines and yet produces a softer dust product than previously achieved.

In an attempt to reach these desired quality standards, ordinary single-handedly! Suggestions have been made for adding a second creping stage to the Yankee paper machine, but generally these are lightweight sanitary paper having a base weight in the range of 8 to 20 bonds/ream with the required degree of softness. I've never had success with tissue backroads. On the contrary, papers of this weight produced on such machines generally do not exhibit the balance between softness and strength required for sanitary paper packaging.

The present invention provides a creped paper that is comparable in softness and strain to uncompressed webs, but can be produced by using conventional equipment incorporating mechanical dewatering and a Yankee dryer that dries the web and then craters. Provides a web binding method. These improved results are achieved by using a double claving process in which the first V-groove is cut into a clave with the highest claving response during the second V-groove processing step. The conditions are adjusted to distort the internal and surface structural conditions of the web in such a way that the Such an arrangement can produce soft paper at a lower cost than the use of through-dryers to enhance paper drying.

According to the present invention, a web is formed from a slurry, the web is applied to the surface of a Yankee dryer, and the web is formed from the surface of a Yankee dryer using a first creping doctor.
The web is creped to a dryness of between 96% and 97%, drawn from a raving doctor, and then processed to a mean square extension of Quegg (later determined) of 9.
The web is treated to reduce the elasticity of the web introduced by the creping step so that the elasticity of the web is less than 1%, and the entire surface of the web is applied to the creping drum with a surfactant, and the web is removed from the second clay from the raving drum. The Ha method of a soft paper web with a base lay of substantially 8 to 2 U bond/2880 square feet consisting of clay 7'' processing with a dryness of at least 96% by a ping doctor is applied.

In this way, the second creping step also yields a web with a structure that lends itself to greater gains than would be possible without modification by making modifications to the method to a conventional paper machine. In the prior art, the web is shaped and dried on a conventional paper binding machine, then stretched at a flat level to create a clay sheet with maximum bulk and flexibility. The present invention has a very low residual tension after Yankee creping and therefore has a low ability to elastically absorb energy during the second regurgitation stage (and therefore does not lead to permanent deformation of its structure). I'm sorry for the insufferable web.

The mean square stretch of the sheet is defined as: MSS
=Me; 了') - YO ■ In this case, MDS is the extension 6th rate in the machine direction, CDS is the extension in the crossing mode, and MSS
is the mean square stretch defined in this way.

Sheets made using conventional papermaking techniques have a mean square stretch (Mss) of about 11%, but the kuep in the present invention before the second crepe caroe step has a MSS of less than 7 strands and less than 6%. The lower MSS Haji has
It represents the relative difference in the energy that can be absorbed by a sheet before the interfiber bonds collapse. MS within this range
The web with S can elastically absorb low levels of potential energy from the creping grade, thus causing greater interfiber bond disruption resulting in increased bulk and softness.

Reduction of the mean square elongation of the web is conveniently achieved by drawing the web under tension from a first creping doctor, and a suitable selection of the minimum speed difference between the Yankee dryer and the creping drum will reduce the web (Be able to give a reliable tension. - For example, 281
The web would be taken from a Yankee running at 0 ft/min and then layered with a second creping cylinder running at 2650 ft/min.
゜The resulting flat elongation of the web between the Yankee and second creping steps is the machine method -] elongation.
MDS 8% and cross direction stretch CD 84.6chi (MS
yielding a structure defined by S 6.1%).

Other means of achieving web tension are also possible.

For example, five tensioning rollers or roller sets can also be inserted between the Yankee and the creping drum.

In order to optimize the operation of creping the web from the second crepe stage, i.e. the creping drum, K is
Very high creping forces can be used to strongly bond (adhere to) the web or raving drum over substantially its entire surface area. Under these conditions, the conditioned queso The best possible breaking of interfiber bonds will be achieved.In order to be able to apply the maximum possible surface area of the web to the creping drum,
The web is taken out of the dryer, the wrinkles are removed from the surface of the web, and the web is stretched and processed. This is suitably accomplished by the same process of pulling the web from the first creping doctor under tension resulting in low residual tension. As the web is pulled from the Yankee with minimal speed difference, its surface flatness is enhanced by minimizing the surface effects of the V-g action that occur at the Yankee's Lade, so that the web has less surface crepe. In this case, this provides a cleaner surface for the coating on the second creping cylinder, creating a larger area of physical contact at the fractured coating interface and thus a larger contact layer; Second - increases the total force transferred to the sheet in the claving step. Alternatively, or in addition, at 0.degree. C., the web can be calendered through a roll to give it the same greater surface roughness, allowing for more intimate contact and a higher total surface layer.

This combination of the web's lower energy absorbing capacity and smooth surface structure results in a reduced L″5 response from the second crepe as it enters the second V-Gloe stage, resulting in a finished Gives the web a gain in bulk and softness.

A direct firing parameter relevant to the present invention is the dryness of the web before the second creping cylinder.

In the present invention, reducing the water source of the sheet to less than 7 inches results in two benefits: First, the ability to bond the sheet to the creping cylinder is greatly improved at island-level dryness. Therefore, the web entering the second creping stage is placed in an optimum moisture content. Second, at this degree of dryness, there is little or no densification at the compression roll that would change the web structure and reduce the results throughout the present invention.

The above percentage characteristics (on the back, in the second crepe, the uneven achievement of +4 knotted tensile strength, which gives the desired layer of softness and bulk. The tensile strength reduction may range from 20 to 50%, but advantageously about 65%.

In the prior art using the second clay process, differential adhesion is used to limit the reduction in tensile strength. However, satisfactory creping response is only achieved for webs with lower burst eruption lengths because the contact is limited to limit tensile reduction.

The present invention uses a second crepe "C" modified weso fabrication and a very high creping response to produce a web with improved softness on both sides of the C sheet. Loeca is characterized by the smoothness of the sheet's lateral surface, the low water content of the sheet, and the corresponding flatness between the sheet and the creping drum, which is caused by the use of an adhesive that is applied all over the creping drum. All of these factors result in contact levels that are more than twice as high as those used in conventional Yankee clay F/In processes. Examples of layering agents are water bath resins such as carboxyl methylcellulose, polyvinyl alcohol, and polyacrylamide, and resins such as acrylates,
It is an emulsion thread of vinyl acetate, vinyl chloride, and methacrylate.

Drum-to-blade clay f 7J11 When the creping drum is increased in a machining operation, the resulting creped web (air turret crepe tension)
It is well known in the art that this agglomeration will show an increase in crepe web tension.
U.S. Patent No. 4,502,2 issued to
It is stated in Column 6062-67 of Specification No. 82.

Therefore, it is possible to utilize aftercrepe web tension as a method of monitoring the amount of adhesion between the web and the kumping drum. There are several ways to actually measure after crepe web tension, and Young describes one such method in column 10. lines 23-54.

Young's patterned web adhesive has a web width of 1c1n.
It shows that the per centimeter was very low, 1.09 per centimeter, and that he was able to increase the yield per centimeter to 2.71 per centimeter of web.

In normal, conventional Yankee dry crepe processing, the after crepe sheet tension is 1.6 g per 10 web width.
6, 5 or 4 at the tangent level, which is very different from the value of
It extends up to one shift as high as g/cm. The adhesion level in the method of the present invention is less than 1 mm per web width (also 1
09 (in one example, the web width is 1 cI).
rL exceeds 11.4.9, which is approximately 3 to 7 times higher than the adhesion level used in conventional Mankey dry creping.

Conventional Yankee clay 7" 7111 machining operations typically yield webs with 12 to 27 clay threads/cm. In the present invention, the finished web has a nominal surface smoothness of 18% for best surface smoothness. It would be better to have at least 55 crepes/cWL after MD stretching.The softness on both sides of the sheet will be improved, but the side that is attached to the dryer will be 60 to 40 crepes softer than the other side. %. Therefore, the softness of the final product of lightweight two-layer tissue with smooth side facing out can be significantly increased by the present invention.

In one embodiment of the present invention, using the same Crater Loe process described above, in a second step the 111II that has not been passed through the dryer and cooled is pressed into the material to be creped to form a sheet. Make a three-turn rapture. The sheet thus obtained has further increased bulk and increased surface smoothness on both sides of the sheet.

Therefore, the present invention provides a series of process changes to the conventional Yankee dryer, continuing the crepe, υΩ process from the beginning to create a web of commercial quality than previously achieved in the prior art, with the same basic properties and strength. The law can be summarized as follows. Higher quality sheets are approximately 8 to 20 bonds/2
880 feet basic rest and crush/(caliper)
) 2 Softness 1.0 to 1.5 and density [0.120 to 0.160.9/softness! !
[Takes the form of a fibrous sheet material.]

A particularly suitable embodiment of the invention will now be described with reference to Figure IfJ.

FIG. 1 compares the performance of the method of the present invention with conventional papermaking methods.

FIG. 2 shows an apparatus for carrying out the method of the invention.

FIG. 6 shows a modification of the device shown in FIG.

@4a4j Figure 4c is web sagging note/Yawara force)
A device for measuring the temperature is shown.

Table 1 below shows the benefits that can be obtained by adding the present invention to a conventional Yankee mounting machine. These profits are based on the basic 1X, the bulk iron IIa per unit r
(The thickness is standardized for Ezuke) and crepe book a/cm<In this case, if the number of clay f streaks/cm present on the sheet is large, the texture of the surface will be smooth).

Table 1 Prior art Crepe book of the present invention/cm 12-27 28+shape/Basic weight cc, Q 6 6.8+Ki Summer y/to 0.18
0.16 The sheet made according to the invention has a lower aEU
/(Caliper) 2, it has a high bulk and a high degree of flexibility and softness. FIG. 1 compares the softness of a conventional dry crepe sheet with that of the present invention over a range of breaking lengths. Original E! A is softer over a range of strengths -
It can be seen that it produces products.

FIG. 2 shows a dfitF apparatus in which a heated creping drum 2 is placed after the Yankee dryer. The web (which may be a single layer web, a multilayer web, or a layered web) is formed and partially dewatered in a Yankee dryer by section 3 (which is conventional and will not be discussed further). supplied to The queso is pressed onto the hot surface of the Yankee dryer and adheres to the hot surface due to its moisture alone or with the aid of a binder sprayed onto the surface of the Yankee dryer upstream from the point of application of the web. .

The web is dried in a Yankee dryer and creped therefrom in a creping doctor 4 at a dryness of 96-97°C. Another blade 5 is provided after the creping doctor to remove excess adhesive remaining on the surface of the Yankee dryer.

The natural shrinkage introduced by the creping action (which can be up to 50% if the web is left untreated after being creped from the Yankee dryer) is removed from the creping doctor 4 under web tension. This essentially eliminates the web as well. The web faces the guide roller 6 and runs between the compression roller γ and the heated creping drum 2. - An example is taking a web from a Yankee running at 2810 ft/min and applying it to a creping drum running at 2650 ft/min. Such a speed difference would lead to the greatest elongation of the crepe wrinkles, with a machine direction II#I straightening of 8% and a bidirectional stretching of 4.6% (half-moon square stretching of 6.1%).
give a web that yields %).

This reduction in web elongation reduces the ability of the web to absorb energy during the second creping process.
The action of pulling the web out of the Yankee 1 under this degree of tension also flattens its surface structure and increases the physical contact area on the creping drum 2, thus increasing the contact level. Make it expensive.

The adhesive can be applied by a mixture of compounds, or as one compound, in one spray, or in separate sprays, or by means of a glimmer, and by superposition of thoroughly dried fibers.
A proportion of adhesive solids of 5 to 1.1% is applied over the entire surface of the creping drum 2. Materials that can function as adhesives include water-bathable resins such as carboxymethylcellulose, polyvinyl alcohol, and polyacrylamide; resins such as acrylates, vinyl acetates, vinyl chlorides, and methacrylates;
It's a thread. In addition to the materials listed above, other mixtures including small molecules such as dextrins can also be used.

A particularly suitable method of applying the adhesive is to use a 1.01113' sougere nozzle as shown in the figure.
The adhesive is sprayed onto the drum 20 surface at a pressure in the range of 150 bonds per square inch gauge (a particularly suitable pressure is 150 bonds per square inch gauge).

At the pressure roller T on the creping drum 2,
The low water content of the web, its smooth surface and the use of all-over chlorine ensure a high level of contact between drum 2 and the web, thus allowing the use of larger blades in the second clave. Maximize your web creping response. The web was prepared using a creping doctor 10 positioned in such a way as to provide the maximum resistance (20 to 60 layer loads) against the adhesive material and at the same time produce the maximum bulk with optimum surface smoothness. From Crepe Power Loe. In keeping with these properties, a creping angle of 4 to 16 degrees radially on the machine at the point of contact is desired for sheeting. This results in a creping angle of 4 to 16 degrees on the radial machine at the point of contact, so that the shed sheet has an average square extension of 8 to 15%. Reels at speed differentials selected to produce a finished web.

A further blade 10 can be placed after the creping doctor to remove excess adhesive from the creping drum surface.

FIG. 6 shows an apparatus similar to that shown in FIG. 2, but now the web 11 passes through calender rollers 11 between the Yankee dryer and the creping drum. The effect of these rollers 11 is to further condition the surface of the creped web so that a very intimate adhesion of the web to the creping drum is achieved.

The method described with respect to the figure is particularly applicable to the production of soft paper webs with very good tactile softness on one side. This is 5 summers.

The nibs should have the softer side of each layer facing the same way out.
Suitable for use in two-layer products. Monolayer, thinner webs can also be made with good tactile softness on both sides by adding a second creping drum to allow creping on both sides of the web.

The raw material used to make the web from the process traps described, if used in conventional prior art methods, would result in nibs that were strong but insufficiently soft. As is often said in this field, such raw materials are
It can be obtained by chemical means or by 0x.

Career No. - Federal Products Corporation (Federal Products Corporation)
ral Products Corporation
), Providence, Rhode Island, USA, using a Federal Bulk Tester. This is 1. with a load of 265 grams.
24 layer sample thickness under 0 square inch circular pad
, 001 inches). The measured thickness is then divided by 24°C to obtain the average thickness of a sheet of tissue paper, or caliper.

Caliper 2 is a combination of two measured paper properties that describes the relative measure of stiffness or deflection of a tissue sample. The crush test is a method of controlling the deflection or strength of the female web. This test is a measurement of the force required to press a preformed ring into the web. The ring is formed by the following procedure shown in Figures 4a-40.

1. 4.5 inch x 4.5 inch tissue sample (
S) is sandwiched between upper disc 11 (1.090 inch diameter) and lower disc 12 (1.435 inch diameter).

2. As shown in Figure 4a, the sandwiched sample (S) is placed on the axis of the circular opening with a diameter of 1.815 inches in the adjustable table 13, so that the surface of the sandwiched part of the sample is thick. sa0
．． 125 inches with an internal diameter of 2.125 inches
It is located on the same plane as the lower surface of JR14.

The edge of the sample is the lower surface of the related ring 14 and the adjustable table 1
3 is placed in the 0.065 inch gap formed by the upper surface of the 3.

6. A fold ring 15 having an inner diameter of 1.502 inches and an outer diameter of 1.750 inches, with the top surface having a radius of 0.625 inches, is placed below the sandwiched sample. As shown in FIG. 4b, the fold [15 is directed upwardly over a distance of 0.250 inches over the tissue sample (El), and the circular hole formed by the upper circular plate 11 and the associated ring 14 is 1 through the 0.065 inch gap formed by the adjustable table 13 and the associated ring 14 to shape the tissue sample into a ring. Every surface ckX reading the sample has a 6 microinch finish and every edge has a radius of 0.0625
having inches. The force required to pull the sample through this 0.065 inch gap is called the folding force or fold, measured in grams.

4. To measure the 8E crush resistance or EE ejection of the sample, close the 0.065 inch gap between the town table 13 and the related ring 14, sandwich the edge of the sample 10, and fold the fold ring 15. Retract. Next, a 2.062 inch diameter sword 16 is applied downward to the ring over a distance of 0.200 inch. (See Figure 40) The force exerted to compress 0 words is called compression, and is expressed in grams.

Collapse/(caliber) 2 is the collapse measured in grams divided by the 2 end of the caliber measured in inches. This performance relationship is expressed in grams per square inch.

Density Density is a measure of the total volume of space occupied by a given unit of Kueb weight. The density of tissue samples is determined by the following procedure.

1) Slice 8 cross-sections from a single layer of tissue sample. 2) W4 Microscope with camera attached to the eyepiece (80x).
Place these cross sections below and take eight photographs of the sample lateral-r plane.

5) Calculate the true thickness by measuring the total area of the photographic photograph using f-rani.

The cap/shape ratio expresses the thickness of the specimen in terms of a normalized straight line of the specimen. Bulk is measured using a Federal Bulk Tester, which measures the thickness of 24 specimens to the nearest inch under a 1 square inch circular pad carrying a 265 gram load. ). The basic gravity line is the weight per unit area of the sample expressed in bonds/2880 square feet. The resulting ratios are not an attempt to combine the individual test units.

This measure is sometimes used as a rough approximation of the relative density of two samples.

The average binding strength of the sample divided by the length of the specimen is sometimes B
reaking LengthΔd Hoc, BLA
〇 () called H MT = MDT The fracture length of the overlapping sample per unit area of the sample can be expressed in meters using the following formula.Two fracture lengths = BLAHX 65 B, 57 meters

[Brief explanation of drawings]

Figure 1 shows the features of the present invention! Figure 2 shows the apparatus for carrying out the method of the present invention, Figure 6 shows the -X shape of the apparatus shown in Figure 2, and Figures 4a to 40 show the device for measuring the deflection/softness of F-nibs 1-01...Yankee dryer 2...Creping drum 3...Web Formation and partial dehydration compartment agent shallow
Hiroshi Mura - 1 Oni - Procedural amendment (spontaneous) March 2, 1985 to the Commissioner of the Japan Patent Office 1, Indication of the case Patent Application No. 7364 of 1985 2, Title of invention Method for manufacturing soft paper web 3 , Person making the amendment 7] Relationship with Tl'l Applicant Address Name Scotto Paper Company (Name) 4. Agent 5. Date of amendment order 6. Inventions increased by the amendment Engraving of the number statement (no changes to the contents)

Claims (9)

[Claims] (1) In a method of manufacturing a soft paper web having a base conductivity of substantially 8 to 20 bonds/2880 square feet, the following steps are performed sequentially: (a) forming the web from the slurry; (b) forming the web from the slurry; (c) Crepe the queso from the surface of the Yankee dryer using a first creping doctor to a degree of dryness of substantially between 96% and 97%; (e) treating the web to reduce the elasticity of the web introduced by the first creping process so that the average square elongation of the web is less than 9%; The above-mentioned method is characterized in that it is passed through the creping drum with a drying agent, and (to) is creped from the raving drum to a second creping doctor with a dryness of 96%. (2) The web is treated to reduce the elasticity of the web introduced by the initial clay processing step by pulling the web under tension from a first creping doctor. the method of. (3) 1 initial clay so that the mean square elongation of the web is substantially less than 6%! 3. A method as claimed in claim 1 or claim 2 in which the web is treated to reduce the elasticity of the web introduced by the processing step. (4) Web processing is performed between the first crepe processing step and the second crepe processing step in order to extend the surface structure of the crepe to a thousand degrees so that the maximum surface area of the web can be brought into contact with the creping drum. A method according to any one of claims 1 to 3. (5) A method according to claim 4, wherein the web is treated to flatten the surface structure of the web by passing the cube between calender rolls. 6. The method of claim 2, wherein the web is drawn under tension from the first creping doctor by maintaining a minimum speed difference between the Yankee dryer and the creping drum. (7) heating the creping drum and applying a layering agent to the creping drum at a point upstream from the point where the web is applied to the drum; The method described in. (8) The web is web 1 ic;
oII sheet tension to the creping drum, and a second claving process increases the tensile strength of the web by 20% and 50%.
8. A method according to any one of claims 1 to 7, wherein the method is reduced by between % and %. (9) The creping angle at the second creping doctor is between 4° and 16° on the line along the radius at the contact point. Method described. 4. Second creping doctor to creping drum K
10. A method according to any one of claims 1 to 9, applied with a load between 20 and 60 bonds per N inch. α1) Any one of claims 1 to 8g10 in which the quag is drawn from a second creping doctor under tension so as to reduce the mean square elongation of the finished web between 8% and 15%. The method described in. u4 The finished web is between 16% and 18% M
4131. A method according to any one of claims 1 to 11, wherein the finished web has a clay fj of less than 28 clays/Crn when measured at D iFp tension. 0.12 and 0.
A method according to any one of claims 1 to 12 having a density of 16 i/cc. u41 Finished web is small (both 6.8cc/I
The method according to any one of claims 1 to 16, wherein the bulk/basic ratio of I is determined. tt! 19. The method of any one of claims 1 to 14, wherein the finished web has a softness measured by a crush/square caliper of between 1 and 1.5. ae First web creping drum! Claims 1 to 15, in which the web side opposite to the viewed side is brought into contact with a second creping drum and creped from there using a third creping doctor. The method described in.