JPS6238480B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an improvement in a tissue sheet having dry crepe made by a wet process, which is used for facial tissue, toilet tissue, towels, etc., and a method for making the same. The sheet of the present invention is soft, has a smooth surface, is bulky, absorbent,
Furthermore, it has at least the same strength characteristics as conventional tissue sheets on the market, which are less bulky and less soft. These properties can be obtained by combining a double structure creped web as a tissue sheet. This web has a two-layer structure, each layer having a smooth surface creped reinforcing layer (first fibrous layer) and a bulky low-bond fiber absorbent layer (second fibrous layer), The latter absorbing layer has a crepe surface with a different amplitude and period from the former reinforcing layer. The web of the present invention has dry crepe.
That is, the formed web is dried to a moisture content of about 14% or less prior to crepe formation. By having a dry crepe, a softer product is formed than with a wet crepe web. Surprisingly, the sheet products according to the invention have a superior surface smoothness feel than dry crepe commercial tissues. This feel can be achieved by a combination of factors including high bulk and softness, but especially by making the crepe very fine. This is accomplished by creping a laminated web consisting of a dense, well-bonded thin layer and a lofty, absorbent, low-bond backing layer. A well-bonded thin layer has a low bending modulus that can give the layer a very fine crepe. When this same crepe process is applied to low-bond fibers, it separates from a dense thin layer, resulting in less fiber contact and a non-uniform crepe. The final sheet is created by combining these features. This sheet has an extremely smooth outer surface and a bulky, elastic middle section.
There is a debond zone between both layers, and an additional debond zone is created between the bond layer and the adjacent low bond layer. The presence of these bulky areas and the elasticity of the fibers improve both absorption capacity and absorption rate, while providing a superior soft feel to the user of the sheet. (Prior Art) Hygienic tissue paper with crepe, such as towels, facial tissue, and toilet tissue, has conventionally been made by a wet method. In this method, an aqueous slurry of wood pulp fibers is poured onto a wire mesh, such as a Four-Dornier wire mesh, in a paper machine, and water is removed from the slurry until the slurry on the wire mesh can be removed from the wire mesh in a web. The web was then sent to a heated Yankee dryer for further drying, thereby creping the dried web. The drying operation creates large hydrogen bonds in the fibers, giving the web strength and increasing density and stiffness at the expense of softness. Creping breaks some hydrogen bonds and stretches the fibers, opening the web and increasing the absorbency, softness, and bulk of the product. The main factors that determine the creping effect are the thickness and bending modulus of the web, and the adhesion of the web to the dryer during creping. Thinner webs produce finer crepes than thicker webs, and webs that stick to the dryer more easily produce finer crepes and are smoother. However, the need for sufficient strength and thickness to handle the web while wet or during the drying process has limited conventional webs to a thickness suitable for crepe-forming blades. In addition, in the conventional method, the fiber composition is uniform throughout the thickness of the web, which is too thin to provide bulk and softness, and in general, two webs are stacked to form a single tissue sheet. I was making it. such 2
For sheets, the side of the web that contacts the drum during crepe processing is often the outer side of the final product. The reason is that the crepe structure on the side surface tends to be finer. It has long been believed that creped or non-creped tissue webs can improve absorbency, bulk, and softness by reducing hydrogen bonding and fiber content that occur during manufacturing. The most common method is to remove water from a water-soluble slurry on a paper machine using a suction box, table roll, or the like. Initially 99.7% water
This dewatering action increases the consistency of the slurry, which was 0.3% fiber, to the point where it can be mechanically compressed into a web. Although this mechanical compaction helps to remove large amounts of water and increase the consistency of the web, it also clumps the fibers, increases fiber hydrogen bonding, and increases web density. In order to prevent this fiber densification and create a soft, absorbent, and strong web, US Pat. Dehydration and drying are carried out using a suction box and radiant heat without compressing the material until it is no longer present. In the crepe web manufacturing method disclosed in US Pat. No. 1,843,656, a freshly formed web is dehydrated using a suction box and an air jet, and then the web is creped on a wet felt drum in an uncompressed state. The rollers are placed in a raised position at the entrance to the creping drum. Furthermore, in U.S. Patent No. 1,868,617, which manufactures paper without applying pressure before drying, heated air is sucked through the web, so radiant heat is applied to one side of the web and suction is applied to the other side to suck the heated air. ing. Other recent methods for creating thick, virtually uncompressible webs with minimal natural bonding include adding chemical debonding agents to the feedstock slurry, stopping agitation of the feedstock, and air drying while heating. The initial fiber formation is then bonded (using pressure or adhesive) in a pattern to provide strength. To increase the effective thickness of the web thus produced, it can be further creped as shown in the following patents: US Pat. U.S. Patent No. 3,301,746 U.S. Patent No. 3,812,000 U.S. Patent No. 3,879,257 U.S. Patent No. 3,821,068 U.S. Patent No. 3,905,863 U.S. Patent No. 3,629,056 U.S. Pat. It is necessary to evaporate a large amount of water without applying pressure. In addition, pneumatic and solvent web manufacturing processes using fiber layers of different lengths have also been described. Also, UK patent no.
No. 1117731 describes a pair of two-layer paper sheets with an absorbent surface on one side and a smooth surface on the ground, with two layers, one made of softwood fibers and the other made of hardwood fibers, that adhere even when wet. has been shown to be resistant. This sheet is creped before final drying. Recent U.S. Pat. No. 3,994,771, which discloses a monolithic paper sheet consisting of laminated fiber layers, bends one layer from the other over a small area corresponding to the network of the fiber fabric. Also, 1977 by the applicant
US patent application Ser. The various methods described above require the use of extremely special equipment in order to obtain products with the correct characteristics, resulting in significantly higher costs than conventional methods. In addition, this kind of soft dry crepe web has a handsheet breaking strength of 20 to 25 per square gram.
The bulk height of the hand sheet is approximately 2.0cc per square meter.
It has the feature of being made from raw materials that are less than gm. (Structure of the Invention) In the present invention, the first fibrous layer of the creped web is a reinforcing layer made from a raw material with relatively high handsheet breaking strength, and the second fibrous layer of the web, that is, the backing layer is bulky. It is made using fibers with low binding capacity, that is, low breaking strength, thus providing bulkiness, suction ability, and elasticity. The first fibrous layer, or reinforcing layer, is thin and has a very fine crepe and a smooth surface.
The layer of the web made of low bond strength fibers on the opposite side of the creping drum surface, the second fiber layer, will also crepe, but the crepe will be coarse due to the characteristics of the fibers and the nature of the crepe. Become. Furthermore, it has been found that fibers with extremely low binding capacity can be used to form two double webs by facing each other to prevent fluffing and contact with the skin. Suitable equipment for this purpose is a conventional paper machine equipped with dual feed ports for separately feeding the fibers forming the first fiber layer and the fibers forming the second fiber layer. There is. Additionally, other benefits can be obtained by using a continuous dryer and not applying pressure. Additionally, the webs tend to delaminate during creping, and the bonding of these bulky webs causes the second fibrous layer of the crepe structure, which has weaker fiber bonds, to be in contact with each other. Yotsutte 3rd
, or a delaminated central area is formed.
This makes it possible to produce crepe tissue sheets that have a better feel than conventional tissue, and in particular have greater softness and smoothness. The first object of the present invention is to have a fiber layer with a dense and strong crepe having an unprecedented thickness and smoothness, and an inner layer of elastic bulky fibers, which is smooth and compressible. The objective is to make dry crepe tissue paper sheets from wood pulp fibers that provide a very pleasant feel to the user. Another object of the invention is to provide a new dual-ply web which can be processed on conventional paper machines and which has an extremely smooth outer surface and a finely creped reinforcing layer (first fibrous layer). This reinforcing layer is lined with a low bonding strength fiber layer (second fiber layer) that needs to be covered to prevent fuzzing during use. Another object of the present invention is to propose a new method for making tissue sheets with dried crepes. The sheets of the present invention according to preferred embodiments have a strong outer layer with very smooth fine crepes, which are simply lightly internally bonded to each other and bonded to the outer layer, and have a lofty, substantially bonded outer layer. It is constructed from a dry crepe web combined with a plurality of uncoated inner layers. Each web has a low dryer weight, i.e., from about 6 to about 15 lb/2880 ft ² (measured in non-creped conditions);
Each constitutes one layer of the final product. As used generally herein, the term "web" refers to a single layer that makes up the final sheet, and the term "sheet" refers to the final multi-web product. Each web is constructed from two layers of fibers, one on top of the other. The first fibrous layer constitutes the reinforcing layer of the web and final sheet and is composed primarily of long, thin, and well-bonded wood pulp fibers. The strength provided by the fibers of this first fibrous layer is such that the breaking strength of a handsheet made using them alone is approximately 30 m ² /gm ² , as explained in more detail below. ) and of such strength that the bulk is less than about 2.0 cubic centimeters per gram (cc/gm). The second fibrous layer is an elastic, bulky, and absorbent fibrous layer made from a raw material having a handsheet modulus of rupture of about 15 m ² /gm ² or less and a bulk value of about 2.5 cc/gm. It is composed of The modulus of rupture and bulkiness (specific volume) are known parameters and will be defined later. The modulus of rupture of the material forming the reinforcing layer (first fibrous layer) is considerably higher than that of normal facial and bathroom tissue, and the material forming the reinforcing layer (first fibrous layer) has a much higher rupture modulus than that of ordinary facial and bathroom tissue, and has a low bonding elastic bulk layer (second fibrous layer).
The rupture modulus of is considerably lower than that of ordinary facial and bathroom tissues and towels. Suitably, the ratio of the modulus of rupture of the reinforcing layer (first fibrous layer) material to the low bond fibrous layer (second fibrous layer) material is between about 2:1 and about 10:1. The fibers that make up each layer of the web are known, but if they are separated from other layers, it is not possible to create a texture with a special crepe. In particular, each layer of this new product provides in the combined state at least one of the properties necessary to obtain a useful texture that are not present in sufficient quantities in the other layer with which it is combined.
one will be granted. For example, the crepe side layer (first fibrous layer) of the web has strength but poor absorbency. On the other hand, the inner layer (second fibrous layer) is inferior in strength but provides bulk, absorbency, and elasticity. Typical values for handsheet rupture modulus at the above ratios are 30 and 15 for 2:1 and 10:
In the case of 1, it is 50 and 5. Double webs have a smooth layer (first layer) depending on the nature of the fibers that make up each layer.
(fiber layer) can be about 70-30% by fiber weight, whereas the low-bond layer (second fiber layer) can be about 30-70%. The fibers of the reinforcing or crepe layer (first fibrous layer) are bonded to each other and are hard, non-absorbent, non-bulky, and non-soft, even with fine creep. That is, when using natural fibers with good bonding properties and strong strength, conventional webs have a high bending modulus and are therefore too rigid to make thin crepes for tissue paper. A suitable fiber for the reinforcing layer of the invention is, for example, northern softwood kraft. By lightly defibrating the fibers, it is possible to achieve handsheet rupture modulus values well above those desired for facial tissue, ie values in excess of 30. This type of paper stock can also contain up to about 25% by weight of short hardwood kraft to create a good layer without substantially reducing the handsheet breaking modulus. In the case of products for facial beauty or bathroom use, they are not soft enough and are too rigid. In the present invention, by lining the crepe layer (first fiber layer) with a low-bond fiber layer (second fiber layer), this crepe layer can be made extremely thin.
It has been found that this layer crepes by unraveling the bonds between its own fibers and between its own fibers and the fibers of the crepe layer during crepe formation. The fibers used in the outer layer (second fibrous layer) include high-freeness thermomechanical pulp or hardly defibrated hardwood kraft fibers, with a Canadian standard of freeness of approximately 600. These fibers hardly bond by themselves, nor do they bond to other bulky weakly bonding fibers, such as crosslinked fibers, regenerated fibers, etc. These crosslinked fibers, recycled fibers, etc. can also be used for all or part of the outer layer side (second fiber layer). These fibers suitable for use in the outer layer side (second fiber layer) have a tendency to produce excessive fluff from the web unless they are surrounded by other similar webs, etc., as in the embodiment of the present invention. There is. The reason for this is that this outer layer (second fibrous layer) itself does not have sufficient strength to maintain its integrity when used as a facial, toilet, or towel tissue. . Creating a very thin crepe layer requires at least two requirements, one is to use a bulky backing layer, and the other is to have a thin crepe layer that is suitable for web handling. The objective is to ensure that the material has sufficient strength. The smooth surface and extremely fine crepe obtained by the thin reinforcing layer are combined with the loose bonding structure between the interface between the low-bond fibers and the reinforcing layer and between the low-bond fibers themselves. By combining this with the resulting elastic bulk layer, an unexpectedly soft product was obtained. DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, the paper making machine shown is conventional, but is equipped with multiple headboxes for forming double webs. Conventional machines of this kind are known, for example, in U.S. Pat.
Please refer to No. 3400045. This paper making machine has multiple rolls 2, 3, 4, 5,
It has a knitted body 1 made of fiber or wire for molding that goes around the surroundings 6 and 7. The knitting body 1 is made of the usual paper web dewatering wire or fibers used in Foullinier machines, the strands of which can be made of metal or synthetic fiber material. Roll 7 has a slightly larger diameter than the other rolls and serves as a slicing roll, that is, a forming roll. A roll 6 with its center aligned perpendicularly to this roll 7 serves as a breast roll into which the material for forming the sheet is fed into a forming area 8 formed by these rolls 6, 7. Ru. Rolls 2, 3, 4, and 5 are direction change rolls,
Roll 2 also serves as a lower roll. The roll is a guide roll that is fixed at one end and movable at the other end, and a suitable known device (not shown) may be coupled to the movable end of this roll to pull the knitted body 1. Roll 3 is knitted body 1 for forming
movable to maintain sufficient tension. In order to drive the knitting body 1, the slide roll 7
It is also possible to drive one or more rolls, such as the lower roll 2 or the lower roll 2. As is well known in the art, any suitable doctor and water shower may be used with the forming fabric 1 during transport to keep the fabric 1 clean. Rolls 10, 11, 12, 13, 14, 15,
The felt 9 provided around the rolls 16, 17, 18, 19, 20, 21, and 22 also passes through the roll 7. This felt 9 is a normal papermaking felt, and absorbs a larger amount of water than a normal dewatering knitted body, and also quickly releases the water. The felt 9 passes around part of the outer circumference of the roll 7 and comes into direct contact with it, and as the knitted body 1 passes around the roll 7, this knitted body 1 is placed on the outside of the felt 9. The rolls 15 have a structure (not shown) for tightening the loops of the felt 9 around each roll.
It is a conventional stretch roll having both ends attached so that they can be adjusted simultaneously by a stretch roll. The rolls 13 are conventional guide rolls used to maintain the felt 9 in a defined path around each roll supporting the felt 9. Rolls 19 and 21 are pressure rolls, each forming a pressure nip with a steam heated Yankee dryer 23 of conventional construction. The crepe doctor 24 is provided to wrinkle the web fed from the surface of the dryer 23, as shown in the figure. Suction box 2
5 and 26 serve to suck water from the felt 9 during movement. Felt 9 is driven through one or more rolls by any known mechanism (not shown). A conventional felt washer (not shown) may also be provided. The dividing headbox 27 has two material inlet areas 28, 29 so that different types of fibers can be fed into the web forming area 8. In an embodiment of the invention, zone 28 is provided with a fiber slurry that will become a reinforcing layer, and zone 29 is provided with a slurry that will be a coarse, bulky, low-bond fiber layer. By doing this, in the case of the apparatus of FIGS. 1 and 2, it is possible to bring the side of the web with the reinforcing layer into contact with the surface of the Yankee dryer 23 and to create very fine wrinkles in this reinforcing layer. A coarser crepe can usually be made on the other side of the web. For convenience, the layer of the web that comes into contact with the surface of the dryer 23 (the first fibrous layer) is referred to as the inner creep layer side, or the simple creep layer side, and the layer on the opposite side of the web (the second fibrous layer) is referred to as the outer layer, or the simple creep layer side. This will be called the outer creep side layer. Raw materials are supplied to the headbox via separate conduits 30,31. Separate systems (not shown) are used to supply feedstock to each line 30, 31, and are well known in the art. The divider 32 extends into the web forming area 8 and the degree of separation of the layers is determined by the desired properties of the final product. The formation of the layers can be carried out so that the layering ratio is 80-90%, ie, only about 20-10% of the fibers in the slurry inlet areas 28, 29 extend into the adjacent formed layer. In many cases, a stratification ratio of 60-65% is sufficient. The fiber slurry that impinges on the forming fabric 1 in the forming zone 8 is immediately dehydrated to some extent and the fluid (water) passes through the fabric 1 into the container 33 . During operation of the apparatus of FIG. 1, the web 36 formed in zone 8 is dewatered as shown and has a consistency of about 8 to 10
%. The web is pressed by rolls 21 into a Yankee dryer 23 to a consistency of approx.
It is further dehydrated to 30-35%. Roll 19 is effective to bring the consistency to about 38-40%. The temperature of the Yankee dryer is approximately 93-99℃
(200 to 210〓. When the web reaches the crepe blade 24, the consistency is about 95%. The felt 9 separated from the web 36 at the roll 19 passes through the suction boxes 25, 26. The felt 9 can be washed if necessary as is well known in the art.The web 36 is attached to the Yankee dryer 23 by
This can be done by its own tackiness.
Alternatively, this may be done by applying an adhesive onto the web 36 or onto the Yankee dryer 23 so that it adheres well to the heated surface of the Yankee dryer 23 when the web 36 approaches the Yankee dryer 23. If necessary, a mold release agent may be used to prevent excessive adhesion. On the side of the inner crepe layer facing onto the dryer 23 of the web towards the crepe blade 24, a fine crepe occurs, and on the side of the outer crepe layer facing away from the dryer 23, a coarse crepe occurs (FIG. 9). . The products produced by the machine shown in Figure 1 are shown in Figures 3 and 9. In these figures, 36 indicates the web, 37,
38 indicate the reinforcement (inner crepe) layer and the low bonding (outer crepe) layer, respectively. Further, numeral 39 indicates dividing areas that exist intermittently throughout the web 36 between both layers. 40 indicates the crepe on the side of the inner crepe layer, that is, the side of the reinforcing layer, and as can be seen from the figure, this crepe is fine and regular, and the degree of crepe is such that the surface is smooth when touched by a human finger. It's starting to give you a feel. However, this inner crepe layer 37 is quite dense, dense and loosely bonded by the crepe action. The crepes of the outer crepe layer 38, indicated at 41, are relatively coarse and have a greater amplitude but less frequency than the crepes of the first layer 37. The difference in crepe, thickness, etc. of both layers is determined by the raw materials from which both layers are made, the characteristics of the product, and the intended use. Although surface smoothness is the most important requirement in the case of facial tissue and bathroom tissue, it is not so important in the case of towels. The separated or unlaminated areas 39 are a series of small unbonded areas caused by the difference in resistance to the crepe blade 24 between the dense, hard layer 37 and the loosely bonded layer 38. Both layers 37, 38
tends to adhere, and there are areas that are adhered for a certain distance until the next crepe. However, this creping action essentially separates the dry web layers and imparts bulk to the product, which is significantly greater than the same web without creping. The intermittent small areas of separation between the layers of the web are shown at 42 in FIG. The web 43 of FIG. 3A is made from the same type of fibers as the fibers of FIG. 3, but the fibers are thoroughly mixed. The product of FIG. 3 can also be made by arranging the headbox and inlet section as shown in FIG. In this device, a forming wire mesh 44 is placed around a breast roll 45, the coarse fiber raw material is fed through an inlet 46, and the inner crepe layer side of the product, i.e. the reinforcing layer side, is fed through a lower inlet 47. The reinforcing layer is thereby provided in contact with the shaped wire mesh 44. Divider is 48
, and both feedstocks are fed via a distribution plate 49 to the areas 49a, 49b shown. In this case, the bulk of the product is a little higher because no pressure is applied by the molded wire mesh, and the product has more moisture and compressibility. FIG. 5 shows this case, in which the dividing inlet 52 is inserted through the slot formed by the dividing plate 53.
Layer both raw materials from
1 is supplied. This wire mesh 51 is supported by a plurality of rolls 54 for normal movement, and the formed web 50 is formed into a suction box 5
5 to a consistency of approximately 25% and sent to a continuous drying fabric 57. The web 50 supported on the underside of the woven fabric 57 is further dewatered by a suction box 58 and then sent to an inlet roll 59 to a continuous dryer 60. The continuous dryer 60 includes a hollow drum 61 having a porous surface through which the heated air is discharged radially to the web moving over it. 50 and is discharged through an exhaust hood 62 to a collector or to the atmosphere. This continuous dryer 60
The web 50 that comes out has a consistency of about 50 ~
At 90%, the exit roll 63 is rotated and the entrance roll or 65 is rotated.
from there to the Yankee dryer 64. This dryer 64 is equipped with a conventional hood 66. After the web 50 passes through a roll 65 that presses the web 50 against the surface of a dryer 64, the continuous drying fabric 5
Separate from 7. A suitable adhesive is applied from the spray 26 to the dryer 64 to hold the continuously dried web on the dryer 64 while the dryer 64 rotates and advances against the surface of the web 50.
applied on the surface of The consistency of web 50 when conveyed by dryer 64 to crepe-forming blade 68 is approximately 95%. The web 50 leaving the crepe-forming blade 68 is conveyed in the usual manner via guide rolls 69 to a winding drum 71. The double web of the final product is 72
It is wound up at the location. In this state, the web is combined with a covering web that is the outer side of the coarse, loosely bonded web. The crepe web 50 has a side 5 of the inner crepe layer on which thin crepes are formed.
3 and a side 74 of the outer crepe layer of coarse crepe. To make the most useful product according to the invention, the creped double web 36 of FIG. 3 (or web 50 of FIG. 5) is wrapped with the coarse fiber side to prevent the fibers from fraying during use. It is necessary to do so. One preferred embodiment is to overlay web 36 with a second web that is the same as web 36. This can be accomplished with the apparatus of FIG. As shown in this figure, the two crepe webs 36 are supported separately and driven by a belt 80 to form web guide rollers 77, 78.
firstly through a rubber-steel calender roll RS and then through a steel-steel calender roll SS. The composite web sheet then passes between a backing roll 82b and a series of laterally aligned crimp rolls 82a and slitters 82. Some of these are the 6th
- Shown in Figure A. The slitter 82 cuts the moving sheet into a desired width and transfers it to the reel drum 7.
Send to 9. The sheet cut in the width direction and wound up is shown at 81 (FIGS. 6 and 7). The crimp roll 82a has a cross-ribbed surface, thereby providing a pair of clamping areas on both sides of each slit sheet 81 to unite the two webs whose rough surfaces (surfaces on the outer claim layer side) are in contact with each other. 83
(Fig. 8). A sheet 81 shown in FIGS. 7 and 8 represents a preferred embodiment of the present invention, and is made by laminating two webs of FIG. 3. The outer layer 40 of this sheet is a smooth fine crepe surface of a dense reinforcing layer 37. Two low-bond fiber layers 38 with rough crepe surfaces 41 are laminated on the inside of sheet 81 via a break-up area 84 or low-fiber lamination area. This segmentation occurs because the fibers have poor cohesion and the rough crepe surface 41 has poor adhesion. Sheet 81 is given bulk by this low-bond fiber property and segmented areas 84. This bulkiness is due to subarea break-ups 85 caused by the non-uniform bonding of the low-bond crepe areas to each other.
It also increases due to the presence of That is, in the thickness direction of the sheet 81, there are three divided areas 42,
85,42 exist. The above-mentioned products are usually used in facial tissues, toilet tissues, towels, etc., which come into direct contact with the user's skin or are printed with patterns or the like. In these applications, the important properties desired by the user are the compressibility of the sheet, the texture and contour of the outer surface, and the loft provided by the coarse fibers without exposing the coarse fibers to the user. These properties have been proven to be satisfied in the products obtained by the following examples through precisely controlled use tests described in detail below. Example 1 A double web was made using the method described in Figure 1.
Hydropulper the two fiber raw materials (not shown)
They were made separately and sent separately to pipes 30 and 31 of the split inlet of the crepe forming machine shown in FIG. The first fibrous material sent to conduit 30 forms the strong drying side (reinforcing layer side) of the double sheet. This material consists of 75% northern softwood kraft fiber, 25% southern hardwood kraft, and 0.5% conventional polyamide epichlorohydrin wet reinforcement resin by dry weight. After this raw material was lightly defibrated using a double-disk defibrillator, the handsheet tape rupture modulus of the raw material on the dryer side was 41.25 sq·m/sq·cm, and the bulk height of the handsheet was approximately 1.9 cc/gm. The fiber feedstock in line 31 consists of 67% by dry weight alder high yield (85%) semi-chemical pulp and 33% broken fiber from the previous run. Thus, there is a mix of northern softwood craft and southern hardwoods. This raw material is not defibrated. The hand sheet tapi rupture modulus of this raw material is 11.57sq・m/
sq cm, and the bulk height was 3.0 cc/gm. Web weighing is approximately 7.8lbs/2880ft ² by dryer weighing.
It was hot. The raw material for the crepe side of the double web, that is, the dryer side (reinforced layer side) is 2880ft ² /4lb
(1.8Kg), and the outside of the double web is approximately 3.8lb (1.7kg).
Kg). The formed web is dehydrated in forming zone 8 to a consistency of approximately 8% and 2
It is pressed against a Yankee dryer 23 which is rotated at 3250 fpm by two pressing rolls 21 and 19. 1st
The pressure on roll 19 was 220 pounds per dryer inch and the second roll 21 was 258 pounds per inch. The formed and compressed sheet is then dried in a Yankee dryer 23 to about 5% moisture and stripped from the dryer to a consistency of about 95% by a crepe-forming blade 24 to a reel (first (not shown in the figure).
The adhesion of the web 50 was controlled by spraying a small amount of epichlorohydrin-modified polyamide resin, which is known as a crepe-forming adhesive, into the dryer 23. Creep pocket or creep forming blade 2
The angle formed between the surface at point 4 and this blade 24 is approximately
At 90 degrees, the ratio of dryer speed to reel speed is approximately 1.20
It was hot. This caused about 20% of the web 50 to crepe, some of which disappeared during winding. Some of the double base web rolls thus produced were laminated (FIG. 6) to make facial tissue. In this case, with the crepe side, i.e. the strong drying side (reinforced layer side) outside, the two layers are rolled at 10 pli between the rubber and steel calender rolls, and the steel -
60pli between steel calendar rolls and 300~
Calendering is performed at a speed of 400 fpm, and the laminated and calendered product is approximately 23.5 cm wide (91/
4 inch) folded as a beautiful facial dress. The 200 sheets folded alternately in this way have a 50% R.
2.2 in the press after conditioning with H.
cm (7/8 in) and housed in a plain white facial tissue box 3.8 cm (21/2 in) high. Approximately 160 boxes thus produced were given code numbers G and subjected to uncharacteristic consumer tests, and comparisons were made with commercially available facial beauty products and experimentally produced products (represented by codes D and U in Tables 1 and 2). . The physical properties of each sheet are shown in Table 1 and consumer responses are shown in Table 2. From this result, code G products have excellent strength in the processing direction and in the transverse direction, and have the same bulk and flexibility, despite containing a large amount of low-bond fibers, approximately 50% of the sheet weight. It is understandable that the absorption rate is almost the same as that of other products with similar properties. That is, Table 2
As is clear from the above, the products of the present invention were highly evaluated by testers in all characteristics. Code C is a typical sample produced commercially by North American Facial, and is usually sold in 200 pieces of 6.3 cm thick pop-up boxes folded together and compressed. During testing, it was simply refilled into a plain white box marked with code D. Code U is another typical sample sample produced commercially by North American Tissue, typically consisting of 200 sheets folded into a C shape in a 9.2 cm (35/8 inch) thick reach-in box. It is stored in a compressed state. For testing, this sheet was refilled into a plain white box with code U. Example 2 Weigh the sheet in exactly the same way as Example 1.
8.0lbs/2880ft ² , but the difference is that instead of alder semi-chemical pulp, the fiber material for the outer crepe side (low bond layer side) was made of 67% flat dry hardwood kraft. The composition of the remainder of the outer crepe side layer (low bond layer) and the crepe dryer side (reinforcing layer side) was the same as in Example 1. The actual hand sheet tapi breaking value of the raw material on the dryer side (reinforced layer side) is
44.0 m ² /sq·cm (615 freeness), and the outer (low bonding layer side) raw material was 8.8 sqr/sq cm (610 freeness). The bulk height of the web tapi hand sheet is 1.85cc/cm on the crepe side (reinforced layer side)
gm, and the outer side (low bonding layer side) is 2.5cc/gm
It was hot. The dryer side (reinforcing layer side) and the outer layer (low bonding layer side) had approximately the same weight. Other processing conditions and molding conditions were basically the same as in Example 1. This example product also underwent consumer testing. Its physical properties are shown in Table 1 and consumer test results are shown in Table 2. In these tables, the product of Example 2 is given the code M. EXAMPLE 3 A product according to this example was made on a tissue machine (FIG. 5) with through-air drying and web stacking instead of wet pressing. The web was formed into two layers using an inlet device equipped with a flexible plastic sheet divider 53 to keep the two materials well separated until they were formed. The reinforcing side (strengthening layer side) raw materials were made by lightly defibrating 75% by weight of northern softwood kraft, 25% by weight of northern hardwood kraft, and approximately 0.5% of polyamide-epichlorohydrin moisture reinforcement resin. The hand sheet tap breaking value was approximately 40. The raw material for the second web side is 100% recycled secondary fiber, to which 1.3 kg (3 lb) per ton of decomposer is added to give a hand tap break value of approximately 15. The web was passed to a continuous drying fabric 57 and vacuum dewatered to a consistency of about 25% at roll 59. The woven cloth 57 serves as a transport cloth for continuously drying the web until it is sent to the Yankee dryer 64. This woven fabric is a monofilament polyester woven fabric commonly used as a woven fabric for papermaking. The web has a consistency of approximately
Hot air at about 71° C. (160° C.) is blown onto the porous drum 61 by a continuous drying cloth until the temperature reaches 80%. The wet web is then conveyed via rolls 63 to the underside of the fabric 57 and is pressed by the transfer fabric into a steam-heated dryer 64. pressure roll 65
The pressure is about 180pli. The web is bonded after drying by sprinkling a crepe former consisting of water and a small amount of polyvinyl alcohol cleaving agent before the sheet contacts the dryer. The web is dried while being transported over a Yankee dryer 64 to a moisture content of about 5%, creped, peeled from the dryer surface, and wound onto a roll. Dryer speed is 76 fpm. The weight of the crepe web on the dryer is approximately 7.0lbs/ ^2880ft2 , of which
4lb is the raw material on the dryer side (reinforced layer side), and the remaining 3lb
This is the outer (low bond layer side) raw material. The two consecutively dried double base webs 50 are then laminated (FIG. 6) with the dryer side (strengthening layer side) outward, with 75 pli between the rubber and steel nips and 75 pli between the rubber and steel nips. The calendered two-layer product is slit and calendered at 100 pli.
They were folded into each other and placed in an unmarked box with beautiful faces, 200 of each. The base weight is reduced but still bulky, so this product is 7.6 cm
(3in) thick box for consumer testing.
Its physical properties are shown in Table 1 and consumer reactions are shown in Table 2. This product is designated by code J in Tables 1 and 2.

[Table] The following consumer test was conducted by dividing 150 to 160 test bags evenly between three test locations. This consumer test was conducted because it is believed that it is more meaningful in demonstrating the quality of the product of the present invention than physical tests conducted to quantify the properties of lightweight tissue. The questions posed to testers are shown in Table 2.

[Table] The above data clearly shows that consumers prefer the three sheets made by the double lamination example to the conventionally available facial tissues. Consumers consider the three sheets in the dual layer example to be softer, stronger and more absorbent than the two commercially available products. Note also that Code G contains 40% semi-chemical pulp and Code J contains 40% recycled fiber, making the final basis weight significantly lighter. These fibers are characterized by elastic bulk, which is highly relevant to what users consider to be an improvement in testing. Although Table 1 shows that the physical properties of each product offered to consumers are within the same general range, the dual layer product is still preferred by test consumers. Example 4 The base web of a two-layer tissue for a bathroom tissue product was made using the tissue manufacturing apparatus shown in Figure 1. The apparatus is provided with an inlet device with a flexible plastic divider 32 extending into the forming area 8 for producing a two-layer web from two raw materials. The first raw material for the side layer of the powerful dryer is supplied to pipe 30, and its composition is 60% sulfite from northern softwood.
, 40% northern softwood kraft, and a small amount of recoid gum. The hand sheet test of the mixed defibrated raw material in this layer has a Canadian standard freeness of approximately 540, and a hand sheet tapi rupture modulus of approximately 32.
m・sq/cm・sq, the hand seat height is approx.
It is 1.87cc/gm. A second raw material for the weakly bonded outer layer is sent to conduit 31 . This raw material consists of 60% flat-dried thermomechanical pulp and
Consisting of 40%. This raw material also contains a small amount of recoil gum in the Broke. This raw material is not defibrated. The freeness of this raw material is approximately
At 190 CSF, the hand sheet tapi rupture modulus is approximately 12.5
m ² /sq cm, hand seat bulk height is approximately 3.50
It is cc/gm. Double web has dryer base weight of 8.1lbs/2880
ft ² , of which 4.1 lb is the strong crepe side material and 4.0 lb is the outer weakly bonded fiber material. The formed web is fed by felt 9 to a single pressure roll of Yankee dryer 23,
It is pressed into the dryer by roll 19 at 350 pli to a concentration of about 40%. A small amount of water-soluble adhesive is sprinkled on the dryer surface to increase adhesion, and the web is dried to about 5% moisture, creped, and wound into rolls. The dryer speed is
It is 3264 fpm. The creped base web is thus stacked in two layers with the dryer side facing outward (Fig. 6), and is rolled up with a steel-rubber roll nip at 10 pli to approx.
Calendered at 300 fpm and formed into bathroom rolls. In this case, no steel-steel rolls are used. The resulting bathroom tissue has the following physical properties: Final basis weight 20.5lbs/2880ft ² 2-layer MD tension 1440gm/3″ strip (3″ strip) % MD elongation 16% 2-layer CD tension 630gm/20 3″ strips bulk height (220g/in ² bottom)
0.090in Example 5 The same web as in Example 4 was made using the machine shown in Figure 1, except that the raw materials were slightly changed and the basis weight was slightly reduced. The first fiber material of the dryer side layer fed to line 30 is comprised of 75% northern softwood kraft, 25% southern hardwood kraft, and a small amount of recoid gum. This raw material is slightly defibrated, its freeness is 575 CSF, and the hand sheet tapi breaking value is
39.0sp・m/pq・cm, and the hand seat bulk height is 2.00cc/gm. the second sent to conduit 31;
The raw material is the outer crepe side layer, which is composed of 60% thermomechanical pulp and 40% broque coming from the previous time, and this raw material is not defibrated. The Canadian standard freeness of this material is 660, the handsheet tap breaking value is 9.5, and the handsheet bulk height is
It is 3.52cc/gm. The two layers are separated by half to approximately 3.6 lbs/2880 ft ² for a total dryer basis weight of 7.2 lbs/2880 ft ² . The formed web was fed by felt to the pressure roll nip of the Yankee dryer, compressed between the felt and the dryer at approximately 360 pli, and sprayed onto the dryer surface to control wet adhesion. Adhere to the dryer with a small amount of Crepetrol 190 adhesive. The web has a moisture content of approximately 5% on the surface of the Yankee dryer.
The material was dried until it was peeled from its surface and wound into rolls. These two base webs were stacked together with the dryer side facing outward, and calendered between steel and rubber nips at 10 pli to form a bathroom tissue roll. The physical properties of the obtained bathroom tissue are shown below. Final basis weight 17.6lbs/2880ft ² Dual layer MD tension 1390gms/3″ strip %MD elongation 14% Dual layer MD tension 430gms/20 3″ strips Bulk height (220lb/in ² bottom)
0.084in The products of Examples 4 and 5 were subjected to a consumer test in which 200 housewives used the product twice in a row on a commercially available British-made bathroom tissue. The final basis weights of Examples 4 and 5 are lighter than commercial products (20.5 and 17.6 lbs/
^2880ft2 vs. 21.5lbs/ ^2880ft2 ), consumers preferred it over the commercial product as shown in Table 3.

[Table] These results compare to the commercially available British product, even though the basis weight of Example 4 is almost the same (20.5 vs. 21.5 lbs/2880 ft2 ⁾ and contains approximately 40% thermomechanical pulp. It shows that the product is definitely liked. Example 5 has a basis weight of 17.6 vs. 21.5 lbs/2880 ^ft2 compared to commercially available products, which is much lighter and approx.
It shows that even containing 40% thermomechanical pulp is slightly preferred. The properties of a paper web are highly dependent on the properties of the pulp material from which it is made. Some of the physical data cannot be determined directly from the final lightweight web, and it is common practice to make laboratory handsheets from raw materials to determine properties such as fiber bonding and bulkiness. There is. This is how the rupture test, generally called the Moulin test, and the bulk height test were conducted. The break test indicates the degree of internal fiber bonding in the web, and in this case represents a factor for each layer of the web. A fracture test allows comparison of bonded webs of the same basis weight. The bulkiness test basically describes the thickness of multiple webs. The handsheet breakage test and bulk height test data used here were all taken from handsheets made under the same conditions. Basically Alice
Using Chalmer's volley hand seat device,
The raw material was sent to a 90x90 mesh Foussfer blue steel plain weave Fourdainier wire mesh lined with a 14x14 mesh plain weave bronze wire mesh to produce a sheet with a basis weight of approximately 60 gm/ ^m2 . The handsheet was pressed and then placed on the smooth surface of an 8" x 8" Valerie steam hot plate with the wire mesh side up to dry. Drying time is 2 minutes. The hand seat height shown here was determined according to Tapi standard T411 OS-68 using a 549 type motor-driven weighted dial micrometer. Each handsheet conditioned at 50% relative humidity for 24 hours was measured at three locations and the thickness was determined in specific volume: cc/gm by the following formula: SV = T/W x 18.08 −cc/gm Where, SV = Specific volume (cc/gm) T = Thickness (microns: 0.001 m) W = Base weight of the hand sheet (gm/m ² ) The hand sheet breaking strength was determined by BF Perkins, Holyoke, Mass. Tapi standard T using a motor-driven Mullen breaking strength tester manufactured by
403 Obtained by OS-D4. This test was performed by clamping a handsheet that had been conditioned at 50% relative temperature for 24 hours in a test apparatus and applying pressure until the sample ruptured. The maximum recorded value of the pressure gauge in pounds per square inch followed by 1.17
The tapi rupture modulus per square cm was expressed as the tapi rupture modulus by multiplying by . Absorption rates were measured by stapled together the corners of 40 sample webs or sheets, placing the composite on water with the stapled side down, and measuring the time until it became completely wet. Absorption rate is the settling time or time to complete wetness in seconds. The flexibility of the tissue was determined by the operator comparing the sample with the standard and observing the hardness and surface fiber condition.
Ratings are on a scale of 1 to 7, with 7 indicating softness. The bulk height of the 20 sheets shown in the table was measured with the first 20 sheets placed on the platform in a stack. A 3 inch diameter cylindrical load of 220 gm/sq in reduces the tissue layer. The thickness under this load was measured and recorded to the nearest thousandth of an inch. It is to be understood that the invention is susceptible to various modifications without departing from its scope, and that the invention is not limited to the particular embodiments shown.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a paper making machine suitable for producing tissue with crepes according to the present invention. FIG. 2 is an enlarged schematic view showing the structure of the forming section of the paper making machine of FIG. 1; FIG. 3 is an enlarged ideal view of the cross section of the web produced by the paper making machine of FIG. 1 according to the present invention. Figure 3-A is a diagram similar to Figure 3 of the conventional web. FIG. 4 is a partial schematic diagram of another type of forming section of a paper machine suitable for the present invention. FIG. 5 is a schematic diagram of another papermaking machine suitable for the present invention, which air-dries the web during transport. FIG. 6 is a schematic diagram of a device for overlapping two webs of FIG. 3. 6th-
Figure A is an enlarged view of the crimp wheel and slitter in Figure 6. FIG. 7 is an enlarged ideal diagram showing the cross section of a sheet made by stacking the webs of FIG. 3 together. FIG. 8 is a plan view showing the final sheet and side crimp areas.
FIG. 9 is an enlarged view of a portion of FIG. 1. 1... Woven fabric, 2, 3, 4, 5, 6... Roll, 8...
Molding area, 10-22...roll, 23...dryer,
24... Crepe forming doctor, 25, 26... Suction box, 27... Head box, 28, 29... Inlet device, 30, 31... Pipe line, 32... Divider, 36...
Web, 37, 38... Crepe side, 39... Break area, 40... Crepe, 42... Break area, 44... Molded wire mesh, 45... Breast roll, 48... Divider,
49...Diffusion plate.

Claims (1)

[Claims] 1. Made of wood pulp fiber, dryer weighs 2880
It has a basis weight of about 6 pounds per square foot to about 15 pounds per square foot (measured per uncreped) and is suitable for use as one layer in a multilayer sheet and has a flexible, bulky, smooth surface. The tissue web is absorbent and has a crepe upon drying, and the tissue web is a one-piece fiber consisting of two layered parts formed of different types of fiber raw materials in the thickness direction. in layers, the first layered portion on one side of this fibrous layer having a creped smooth surface and primarily having a hand sheet tapi rupture modulus of greater than about 30 square meters per square meter. a long, thin and fine wood pulp fiber material having a bulk value of not more than about 2.0 cubic meters per handsheet; The layered portion has a creped surface composed of a fibrous raw material with low fiber interconnection strength having a coefficient of rupture of less than about 15 square meters per square gram and a bulk height of more than 2.5 square centimeters per gram. the second portion does not have sufficient interfiber integrity to prevent fiber linting; A web characterized in that broken portions formed by breaking between portions are formed intermittently. 2 The first layered portion is about 70 to 70% of the weight of the web.
30%, and the second layered portion is from about 30% to about 70% of the web weight. 3. The method of claim 1, wherein the ratio of the handsheet rupture modulus of the first layered portion to the handsheet rupture modulus of the second layered portion is between about 2:1 and 10:1. Tissue web listed. 4 The ratio of the bulkiness of the first layered portion to the bulkiness of the second layered portion is at least about 1:
1.25. The web according to claim 1. 5. The fibers of the first layered portion are comprised of at least about 75% by weight of long, thin, and fine wood pulp fibers, and the proportion of the fibers is at least about 75% by weight of long, thin, and fine wood pulp fibers. The tissue web according to claim 1, which has a value that does not substantially impair the smoothness of the surface. 6. This first layered portion can be easily formed with almost no decrease in breaking strength compared to that provided by long, thin, and fine fibers. The tissue web according to claim 1, wherein the layered portion contains a large amount of relatively short papermaking fibers. 7. The long, thin and fine wood pulp fibers are made from softwood and the short paper pulp is made from hardwood and comprises no more than about 25% of the weight of the first layered portion. The tissue web described in item 1. 8. The first layered portion is comprised of approximately 75% by weight of long, thin, and fine softwood kraft fibers and approximately 25% by weight of hardwood; The tissue web according to claim 1, which has a breaking strength (and tensile strength) of about 100%. 9. The first layered portion has fine crepes, and the second layered portion has crepes with a smaller period and amplitude than the first layered portion. Teishu Web. 10 2880 A tissue sheet laminate having a basis weight of from about 12 to about 30 pounds per square foot and having a flexible, lofty, smooth surface and absorbent material, the thickness of which is a first web and a second web stacked one on top of the other in a transverse direction, the first web having a relatively dense first layered portion having a creped smooth outer surface;
has a relatively lower density than this first layered portion,
and a second layered portion having a creped surface opposite to the first layered portion and further forming a bulky and elastic backing layer of relatively low density; The second web has a second layered portion forming a bulky, elastic backing layer and a creped smooth outer surface and is lined by a second layered portion of the second web. a dense first layered portion, and a second layered portion of the second web has a creped surface opposite a creped surface of the second layered portion of the first web. a first fracture zone is formed between the two layered portions, and each of the first and second webs includes:
There are intermittently fractured areas between the first layered portion and the second layered portion, which are formed by breaking between these two portions, and thereby, in the sheet thickness direction,
A tissue sheet laminate characterized by the presence of three layers of fracture zones. 11 Each first layered portion has approximately 30
having a handsheet tapi rupture factor of greater than or equal to about 2 square meters and a handsheet bulkiness factor of no greater than about 2 cubic centimeters per gram, each second layered portion having a handsheet tapi rupture modulus of greater than or equal to about 15 square meters per square gram; and a bulk factor of greater than or equal to about 2.5 square centimeters per gram. 12. The tissue sheet laminate of claim 11, wherein the first and second webs are bonded to each other to prevent separation and to prevent fuzzing of fibers from the sheet. . 13. The tissue sheet laminate of claim 12, wherein said first and second webs are joined together by a longitudinally extending embossed area.