JPS59112092A - Paper and production thereof - 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]

The present invention relates to paper and a method for manufacturing the same, and more particularly to a paper with a novel structure and a method for manufacturing the same. Included within the term "paper" are hydraulically deposited webs of fibers of all kinds, including, for example, fibers made from cellulose, glass, asbestos, carbon fiber, mineral wool or other synthetic materials. According to prior knowledge in the paper art, it is possible to form suitably agglomerated papers from slurries of cellulosic fibers, such as wood, cotton or flax fibers, which have been subjected to suitable treatments (e.g. beating or defibration). Binders or other materials may also be added. The interaction between the fibers depends in part on mechanical interlocking, but primarily on friction, such as occurs due to hydrogen bonding between the fibrils formed during the process to which the fibers are applied and the hydroxyl groups present on the fibers. Binders, if present, provide for adhesion between fiber surfaces or the formation of a self-bonding matrix in and around the fiber web. There are many fibers (particularly synthetic polymeric fibers and inorganic fibers) that have weak intrinsic engagement, and there are applications for which such bonding without a binder is inappropriate. For example, if the fibers in question are glass, mineral wool fibres, quartz and alumina, or ion exchange resins,
When adding non-fibrous materials such as silica gel or activated carbon, it is impossible to have strong strength without a binder. Moreover, cellulose fibers, on the one hand, engage with adequate strength, while inorganic fibers, such as glass fibers, on the other hand, can form papers with some strength through special treatment, but with the use of large amounts of binder or pre-manufactured paper. It has not heretofore been possible to create materials in which layers made of certain fibers form strong interfaces, except by adhesive lamination of webs. Engagement between one type of fiber in one layer is achieved by one mechanism, but to the extent that the fibers of the same material are treated differently or have different lengths or thicknesses in each layer. Even in cases where the fibers are of different types, it has been found that engagement between the different types of fibers in the separation layer occurs by different mechanisms. One layer is usually stronger than the other. The problem of forming interfaces is particularly difficult when the fibers are different in each layer. It is especially difficult when the fibers in each layer have different materials. If large thicknesses are not required, the paper is generally made from a single slurry and the special surface is provided by surface treatment of the web, such as the application of a coating or size. However, for many applications, it is the surface properties of the paper that are important, and the bulk of the paper only provides mechanical strength. On the other hand, one property may be desired on one surface and a different property on the thickness of the paper or other surface. Therefore, in such cases, the paper is made in a single step by choosing the material of the surface layer of the paper itself in order to give it the desired properties and to make other surfaces of the paper body or other materials. This is economical. For example, in chemical processing/filtration applications, it is desired that the paper has inert surface properties, with the exception of reactive materials such as ion exchange compounds incorporated into the paper body between two surface layers. . On the other hand, in filter papers, a layer of glass fibers with the desired filtration properties may be supported by a layer of cellulose or another glass fiber that provides mechanical strength. What is desired is a facility for making fairly thick papers from thin layers of fibers which, due to their nature, cannot be practically applied in sufficient thickness (e.g. due to slow water movement due to the extreme fineness of the fibers). It has previously been proposed to produce relatively thick paperboard with homogeneous fibers in the transverse direction by a continuous "etch-on-wet" process. In this method, a first fiber slurry is deposited on the screen of a Fourdrinier machine, and while the first slurry is wet, the second fibers are deposited in the first fiber slurry such that interlayer mixing of the fibers takes place. Deposit on top of the slurry. In this method, it is known to introduce the second slurry into the first slurry at a slower speed than the first slurry is moving. A theoretical discussion of the “wet-on-wet” method is provided in B.
, Radvan and A. J. Willis, P.
aperIndustry ConEerence
Papers” (October 26-28, 1982
Day, Harrogate, Exhibi

[ion
CenLre. at the Royal Hall). Although not detailed, the discussion is with respect to conventional cellulose paperboard, where the paperboard fibers have the same physical and chemical characteristics throughout the thickness of the paper. Radvan and Willis addressed the problem of forming a second layer on top of the first layer without disturbing the first layer by reducing the number of interfacial fibers on the paperboard so that the paperboard is homogeneous. There is. To conclude this, they proposed a "coand
A effect has been adopted. The success of such methods relies on hydrogen bonding between cellulose fibers and the presence of binders normally present in the slurry. The possibility of fundamentally influencing the fibrous structure of the web (e.g. by repeated application of "micro-turbulence" throughout the forming process)
, Radvan and Wi as to be found in the future.
llis, this teaching is along the same lines of minimizing perturbations in each layer. U.S. Pat. No. 2,098,733 teaches the practice of thicker paperboard by depositing a second slurry over the first slurry while it is still wet to provide interlayer mixing of the fibers. A manufacturing method is described. The fibers of the first slurry are longer than the fibers of the second slurry. Again, the process is controlled to minimize the number of fibers oriented across the paper so that the paper is homogeneous. A sizing agent is included in both slurries to achieve adequate bond strength, and it is believed that a water glass adhesive may also be used. The method of depositing a second slurry on a partially dewatered first slurry is used to produce paper consisting at least primarily of asbestos fibers. Throughout the width of the paper, the fibers have the same chemical and physical properties, but the fibers in one layer are often more densely packed than in others. In this method, the degree of agglomeration of the fibers is controlled to provide fibers in the Z direction to improve bonding (U.S. Pat. No. 3,353,6
No. 82). Paper made by the above-mentioned known method is weakest at the interface between adjacent layers. Even though the fibers across the width of paper made by such known methods generally have identical chemical and often physical properties, they often require large amounts of binder to achieve adequate strength. (In particular, U.S. Patent 3
, 353, 682)). However, the existence of such a binder
In applications such as scientific research papers and battery separators,
Totally undesirable (use of a single layer containing coarse and fine glass fibers and no binder). In other applications such as clean gas filters, such as air filters, especially so-called "HEMAJ" (high efficiency granular air) filters, the presence of more than a small amount of binder is completely undesirable, but in the past sometimes paper It is known that in battery ablation plates or HEPA filters it is desirable to have one layer of relatively coarse fibers and another layer of fine fibers. , it was believed that too much binder would not form a unitary structure, so the two layers were manufactured separately and then laminated with adhesive or mechanically (e.g., U.S. Pat. No. 4,262,068). ).Battery separator or HEPA consisting of a single sheet of variable density throughout its thickness, binder-free, and made in a single process.
It is particularly advantageous to be able to provide filters. According to the present invention, the fibers of two separate slurries are typically bonded together during a papermaking operation from separate slurries having different fibers (i.e., chemically and/or physically different), and the fibers of two separate slurries are mixed. This allows for the production in a single step of a paper having at least two layers brought together at an interface comprising a region of the invention. If the first slurry has fibers A and the second slurry has fibers B, the paper structure is layer A, interface A
10B, layer B, and optionally interface B1G, layer C, etc. In the present invention, this is accomplished without the use of binders. The present invention is used in a papermaking process where multiple layers of separate slurries are deposited on top of each other in the paper machine so that the composite is wet-stacked and the physical bond between the two slurries is The second layer is applied to the first layer in a manner specific to the relationship and composition of the two slurries, such that disturbance occurs only at the surface of the two layers and the fibers of the second slurry are applied between the fibers of the first slurry. To provide a method for making paper in which fibers are penetrated and substantially undisturbed fibers remain throughout most of the thickness of each layer. Such control allows for the creation of interfaces that are at least equal to, or stronger than, the strength of one and possibly all of the layers, without the use of binder materials, even when the fibers of the two layers are completely dissimilar. It was found that it can have an adhesive strength of . This is because controlled turbulence causes the fibers to mix at the interface between adjacent layers. This causes the fibers to bond together. The fibers will then engage and resist pulling apart when attempting to pull adjacent layers apart from each other. Therefore, the paper tends to separate along planes at two adjacent layers much weaker than at the interface. When attempting to delaminate, a high proportion of the top layer fibers end up bonding to the bottom layer through the interface. In this way, the ability to bond adjacent layers together allows for changes in the chemical properties of the fibers, changes in physical characteristics (particularly fineness), and other additives that may be desirable for the paper to contain for certain applications (in research filter papers). A binder-free unitary structure is obtained with characteristics that vary in width, including variations in loading of silica gel or ion exchange resin particles, or perlite in battery separators. The physical relationships of primary importance in the method of the invention are:
Relative velocity of the two slurries when applied, the first slurry
The first layer of the flow box nozzle is. By using these variables, it is possible to control the extent of fiber mixing at the interface and the extent to which the fibers are reoriented at the plane interface where fibers are predominantly deposited in each layer. The liquid content of each layer plays a part in determining the properties of the final paper. It is particularly preferred to introduce the second slurry into the first slurry at a faster rate than the speed at which the first slurry is moving. In some areas, the use of binder materials is completely undesirable. Totally undesirable in areas such as scientific research papers such as filter paper. The purpose of using fibers such as glass fibers is to provide paper that is completely chemically inert and pure. The presence of binder in such papers is detrimental to the results obtained, as it introduces chemical impurities and reduces the filtration effectiveness. Binders are also highly undesirable in battery separators; binders are not chemically compatible with the electrolytic cell and limit absorption of electrolyte into the separator. Another aspect of the invention is to provide a paper (particularly in the case of binder-free paper) comprising fibers of both layers and made entirely of different fibers in each layer with interfaces between the layers that cause agglomeration between the layers. There is a particular thing. Fibers may be chemically and/or physically different. Additionally, to one or other or all layers, non-fibrous materials suitable for paper use may be added in one slurry step or deposited thereon, and the non-fibrous materials may be deposited in a research environment. contains ion exchange resin particles, and under normal conditions the surface layer (which may be thinner than other layers)
added to give the desired surface characteristics. By controlling the properties of the interface, it is possible to influence the properties of the entire paper. For example, the nature of gas cleaning filters such as filter paper, battery separators or air filters (in particular so-called [HEPAJ filters) is such that when applying a second or other subsequent slurry, much turbulence, non-orientation and mixing are induced. be influenced, even determined, by controlling. When applying one layer to the next, the preferred parameters for the relative concentrations and relationship of adjacent layers are determined by the respective properties of the two fibers involved. The more similar the fibers in the two layers are, the greater the height and fall angle of the next slurry should be, especially if one (and also both) layers have weak bond strength within the layer. It is. Depending on the required paper properties,
Relative velocity, angle and height may be chosen independently of each other. A suitable falling angle is 1.5 to 2o0, preferably 2o0.
．． 5 to 17. For many papers, a particularly suitable angle is about 4-6 degrees. The height is 1 to 5 vm, preferably 1 to 20 vm, and more preferably 1 to 10 vm. The difference in velocity between the two slurries is 2-15%, preferably 2-12%, more preferably about 5-7% for many papers where the second slurry moves faster than the first slurry. layers (e.g. average diameter 0.49-0.5
Johns Manville Q of 8 tt m
When applying glass fine fibers) to a cellulose layer (e.g., cotton), the glass slurry is most effective when applied to the cellulose layer from a height of 8 gates at a fall angle of 7°. Below is a layer of glass (e.g. Johns Manvi with an average diameter of 0.34~01487zm).
lle IQ4 glass fine fibers), respectively 6.
Orrvn, 4.0° is required. In all cases it is critical to control the concentration of the layer during application. The first slurry is still fairly fluid;
Depending on the nature of the paper being made, preferably 80-95% by weight, more preferably 86.5-93.5% by weight, even more particularly 87.5-92.5% by weight, especially 89-91% by weight M
% of water, and the first slurry contains 98 to 99.9% by weight, more particularly 99.0 to 99.8% by weight, especially 99.0% to 99.8% by weight.
The second layer should be introduced into the first layer when it contains 5 to 99.7% by weight of water (in all cases the remainder is solids content). If used, add a third slurry to 85 to
It may be applied at a concentration of 95% by weight, more particularly 90% by weight N of water, when both the first and second layers together have a concentration of 89-91% by weight of water. In this case, when the first two layers are compressed to some extent, the first two (
Formation of the interface is aided by mechanical disruption of the surface of the third layer by passing the third layer through a roll and reorienting the third layer immediately before depositing it on top of the (or more) layers. In each case, the interface formed from the mixed fibers is about 5-10% of the total thickness of the two layers, more usually about 1
The thickness of the interfacial layer is mainly determined by:
However, not solely (and more than the above-mentioned concentrations and variables) depends on the nature of the first layer. In this way, a structure consisting of two or more layers of cellulose, synthetic organic or inorganic fibres, In particular, by such a method, multilayer structures can be made for use as gas purification filters or battery separators with paper having a density gradient. The fibers at the interface between each adjacent layer are well mixed and bonded to provide sufficient cohesion between the layers without the need for a binder. A paper with a zero density gradient has not hitherto been described in the literature. The battery separator according to the invention is particularly suitable for use in gas recombination batteries requiring separator integrity. Yes, the monolithic separator is bulky enough to absorb and retain the electrolyte, allowing gases to pass through, but effectively blocking the passage of objects such as small crystals that are harmful to the battery. The method of the invention allows for the particularly effective use of fibers during the manufacture of battery separators. In the method according to the invention, the fibers of each slurry differ from each other in physical and/or chemical characteristics. Moreover, any slurry may contain a mixture of fibers that differ from each other in physical and/or chemical characteristics. The fibers may be natural or synthetic, inorganic or organic, for example wood pulp, (natural or regenerated) cellulose fibers like cellulose acetate for cotton, inorganic fibers like alumina for glass, asbestos, natural organic fibers like mineral wool, and polyesters (e.g. polyethylene terephthalate), polyolefins ( for example,
polyethylene, polypropylene), acrylic resins (polyacrylonitrile), carbon fibers, polyamides (e.g. nylon), especially aromatic polyamides (e.g. K
evlar 5Kevlar is commercially available from Du Pond. ), synthetic organic fibers such as Because it does not react with the hydrofluoric acid emitted by the reactor, Kevlar is a
Particularly suitable for PA filters. Preferred papers made by the method according to the invention may contain at least one non-cellulosic fiber, which may be selected from inorganic or synthetic organic fibers (e.g. glass, polyamide or polyolefin). . Another preferred paper is one j-
and one other layer of non-cellulosic fibers (eg cellulose on glass, especially fine cellulose fibers on relatively coarse glass fibers). The method of the invention is particularly suitable for making two papers having two adjacent layers of non-cellulosic fibers. For example, a filter in which the two layers are each made of polyester and glass is useful in a gas mask. The fibers in each layer are chemically the same as the other fibers and may differ in the thickness of each layer. When made entirely from glass, paper provides a particularly suitable battery separator or HEPA filter. If glass fibers are used, they may have a wider range of thickness than many other fibers. In this way, the glass in fine layers is manufactured by Johns Manvi
lle 100 fine fibers (average diameter 0.2-0.29μ
It has m. ), while the glass in the coarse layer is described by John Manville "Ch
op Pak J fiber (length approximately 12.7 or 6.3+
Typically, battery separator membranes have an average basis weight of 60 to 2
40 ri/i and two layers, i.e.
Manville l 12 and 110 fine fibers (average diameters, 2.6-3.8 and 2.17-3.10, respectively)
μm) coarse layer, and Johns Manvill
e IQ 8 or 106 fine fibers (average diameter each,
It may consist of a fine layer of 0.59-0.88 or 0.49-0.58 μm). The glass may be borosilicate glass with or without oxidized salts (e.g., Johns Manville 4, respectively).
75 or 753). A two-layer battery separator embodying the invention comprises layer (1) - nominal fiber diameter of 3.5 μm and gram age (pramma
@e) Composition of acid resistant glass microfibers from 50 to 250 F/-d, layer (2) - (and layer (3) if used) - nominal diameter 0.65 μm and gram age (9 rammag e).
) 5 to j00F/7y1''. In the case of a three-layer structure, layer (1) is combined with layers (2) and (3) forming the outer surface of the structure. The qualities achieved by such a single fiberglass separator according to the present invention are: 1. Stability in sulfuric acid; 2. (al The use of a thin continuous layer of fine fibers to provide a microporous structure and reduce the possibility of undesired migration between the electrodes, and the ability to absorb significantly more electrolyte per unit weight of the separator (BL) A binder-free backing structure that provides the ability to use various grades of glass fiber more effectively by increasing the bulk of the material by using a continuous layer of coarse fibers that are thin. Improved strength compared to a single, mixed layer of fibers.In the unitary construction that is an embodiment of the invention, a thin layer of fine fibers is applied to this layer without binder or mechanical assistance. A typical HEPA filter has an average weight/unit area of 6
0 to 110 P/d and two layers, i.e. for example J
a coarse layer of ohns Manville e 112 fine fibers (average diameter 2.6-3.8 μm), and Johns
Manville 110 fine fiber (average diameter 0.2
0.29 μm). The glass may be borosilicate glass containing a small amount of salt oxide (e.g. J o
hns Manvi ] le475). The two-layer HEPA filter that is an embodiment of the present invention includes (a)
Layer (1) - 50 to 50 glass fine fibers with a nominal diameter of 0.3 μm
100%, synthetic organic fiber 0-50%, preferably 5-5
0% and acrylic resin binder O-10% Gram Age (pramaFe) 20-200
Composition of F/I, layer (2) - composition weighing 5-100 g/I with 90-100% glass fine fibers of nominal diameter 0.65 μm or less and 0-10% additives, (b) Layer (1) - Gram Age (S') with 50-100% cellulose and 50-100% synthetic organic fibers;
rarrlrllali'e) 10-100 F/d composition, layer (2) - 90-100% glass fine fibers with a nominal diameter of 0.65 μm or less, and 0 additives
Durham age with ~10%
5 to 100v/771".
PA filters have the following advantages over conventional filters, which are homogeneous mixtures of glass fibers: 1. Replacing relatively fine fibers with coarse fibers in a portion of the thickness improves paper strength. It reduces pressure drop without loss and also means cheaper materials can be used. 2. The ice crystals pass through the rather large pores in the continuous coarse fiber layer structure, the so-called "prefilter" layer, through the intermediate sized pores in the central (mixed fiber) part. It has a pore size gradient leading to much smaller pores in the continuous tapered fiber layer structure. 3. Ice crystals evenly distribute throughout the product for more effective depth filtration. 4. By carefully designing filters/pre-filters for special applications, throughput can be greatly increased. 5. In a given process (i.e. the same weight of granules),
The pressure drop in a multi-density filter is lower than in a single layer filter. 6. The fine fiber layer is protected by the pre-filter, which extends the service life of the filter. 7. The amount and diameter of fine fibers used are determined by the required filtration performance. This leads to a more efficient use of expensive fine fibers. In the accompanying drawings, FIG. 1 is a schematic diagram of a fourdrinier machine modified to carry out the present invention, FIG. 2 is a detailed diagram of the flow box nozzle portion to which the second slurry is applied, and FIG. Figure 7 shows, at different magnifications, micrographs of partial cross-sections of various papers according to the invention showing the interface areas. Fourdrinier machine 1 has a conventional flow box nozzle 3 that deposits slurry onto a moving web (or "screen") 4 to form a wet fiber layer 5. The water is then drained conventionally into a reuse/treatment sump sump 6. At a selected location along the screen, a second flow box 7 is placed and fed with another slurry from a second header. - Depends on the composition of the slurry, the wire speed, the drainage rate and the height of the second flow box nozzle 8 from the first layer (when the second slurry is introduced ζ0 to the upper surface of layer 5 with a known concentration) Directly from the flow box nozzle 8 a stream 9 of the second slug IJ- is discharged. The nozzle 8 is set at a height h from the surface of the layer 5 and has an outlet angle α with respect to the layer 5. The velocity of the layer 5 is ■□, nozzle 8
The velocity of stream 9 emerging from is v2. The effect of this velocity and the concentration that slurry stream 9 contains about 99.5% water and layer 5 contains about 90% water is to create turbulence only at the top surface of layer 5 and at the interface between both layers. 10
is to cause mixing of the fibers of the two layers. If the fibers of the second slurry are finer than the fibers of the first slurry, they may be drawn into the first layer by gravity, drainage or suction to increase the effect of turbulence at the interface. If the fibers in the second layer are coarser than the fibers in the first layer, you can consider penetrating the first layer like a stake and connecting the layers together. The composite layer then passes through a suction belt 11 and a drying roller 12 as usual. If desired, a third layer may be applied from the third flow box 13 and compressed onto the composite layer through the auxiliary screen 14;
At this time, the composite layer has a water content of 89 to 91% as a whole,
The third slurry has a water content of about 90fo. Examples of the production of various papers using the apparatus of FIGS. 1 and 2 are presented below to further explain the invention. Example 1 Preparation of Fine Earth Wood Pulp A first slurry was made from cotton fibers and a second slurry was made from wood pulp. The first slurry was run over the screen and at the point where its moisture content was 90%, the second slurry was applied to the first slurry by a second nozzle. The height h from the surface of the layer formed by the first slurry is 3 mm, and the angle α
was approximately 3°, and the velocity V2 was 5 or 6% greater than the velocity V1 of the layer formed by the first slurry. The concentration of the second slurry at the time of contact was 99.5% water. The agglomerated two-layer paper is formed after the conventional drying and compaction steps, and it is difficult to separate the two layers of paper, and the interface, according to the microscope, reaches about 10% of the paper thickness. , where there is a great deal of intermixing and non-orientation of wood pulp and cotton fibers. Example 2 Production of brocade glass fiber The first slurry was made from cotton fibers, and the second slurry was made from JOIII.
Made from IS Manville 104 glass microfibers. The first slurry was run over the screen and at the point where its moisture content was 90%, a second slurry was applied onto the first slurry by a second nozzle. The height 11 from the surface of the layer formed by the first slurry was 10Hn, the angle α was about C, and the speed v2 was about 5% larger than the speed 1 of the first layer. The concentration of the first Niss slurry at the time of contact was 99.6% water content. The agglomerated two-layer paper is produced after conventional drying and compaction stages (
The two layers of paper were inseparable in the sense that the bond strength between the layers was greater than the interfiber bond within the glass layer. Examination of the structure of the paper showed an intermediate layer]O in which the fibers from the two layers 5 and 9 were intermixed and non-oriented. Layer]O
The thickness was approximately 10% of the paper thickness. Cross-sectional views of this paper are shown in Figures 3, 4, and 5 (magnifications are 500x, 1800x, and 5500x, respectively). Figure 5 is interesting as it shows the glass fibers penetrating the cotton fibers at 15. This product provides a particularly tough and flexible liquid filtration media. Example 3 Production of brocade glass fibers Johns Manville IQ5
Example 2 was repeated except that the fibers were fine and the nozzle was 13 steps above the surface of the first layer and at a 9° angle. A micrograph of the produced paper at a magnification of 550 times is shown in FIG. Example 4 Preparation of Glass on Glass First Slurry in Johns Manville Q
8B From the glass fine fibers, make the first slurry
Made from Manville 104 glass fiber. The first slurry was run over the screen and at a point where its moisture content was 91.5%, a second slurry was applied onto the first slurry through a second nozzle. The height h from the surface of the layer formed from the first slurry is 4 m, the angle α is approximately 3°, and the speed ■2 is the speed ■1 of the layer formed from the first slurry.
5 or 6% larger. First Niss Rally at the time of contact
The concentration was 997% water content. The agglomerated two-layer paper was formed after conventional drying and compaction steps, and separation of the two layers of paper was not possible in the sense that the bond strength between the layers was greater than the inter-fiber bond within the glass layer. . Examination of the structure of the paper showed an intermediate layer 0 in which the fibers from the two layers 5 and 9 were mixed and non-oriented. A micrograph of the produced paper at a magnification of 550 times is shown in FIG. This structure is a particularly effective pre-filter (or depth) filter, especially i(:IIEPA).
Provide a filter or battery separator. Example 5 Preparation of glass on glass/polyethylene Knee 1st slurry in Johns Manvi II e l Q 3
B glass fine fiber 90% and 5olvay Pu1p
From 10% cx polyethylene fiber, Jo
Example 4 was repeated except that it was made from hns Manvi I 1e104 glass fine fibers. The agglomerated two-layer paper is formed after conventional drying and compaction steps, and separation of the two layers of paper is not possible in the sense that the bond strength between the layers is greater than the inter-fiber bond within the glass layer. Ta. Examination of the structure of the paper showed an intermediate layer 10 in which the fibers from the two layers 5 and 9 were mixed and non-oriented. Similarly, a significant amount of particles of non-fibrous material or ion exchange material may be added to one of the slurries. A flexible liquid filter with high wet strength was obtained. Example 6 Preparation of Glass on Polyester A glass fine fiber slurry was deposited on a polyester fiber slurry in the same manner as in Examples 4 and 5 with similarly satisfactory results. It is useful as a highly effective gas mask medium. Examples 7-11 Papers particularly suitable as HEPA filters and battery separators were made as follows: Apparatus 1, Black Clawson 8 Feet) HC
VT Ti1e hydra pulper, 24 inch diameter Vokes Roter and drive - 100 horsepower, 1800 rpm Westinhouse motor. 2. 5-entile Chest in 3000 and 7000 gallon capacities with side-insertion lightning mixer. 3. BlackCl- installed on a 36-inch fourdrinier
awson secondary flow box. 4. A 36-inch fourdrinier paper machine, which will be explained in detail below. 5andy HillCorp, which has a screen width of 36 inches and is designed to operate at speeds of 5 to 300 feet per minute.
oration fourdrinier paper machine. Manifold type inlet and various specially designed homogenizers, distributor rolls and neilson
Dual action with slice (static, pressurized or depressurized)
head hox. 3 on a 15 foot long platform
Fourdrinier stand that can be tilted and adjusted by inches. The press section consists of two main presses, the first press being a straight-through plane press and the second press being a reverse plane press. The rolls are made of various special rubbers and sto
nite) made of cast iron with a cover. One smooth press has a straight through progression. The drying section consists of seven dryers: five dryers with fully cast bearing sections and two felt dryers on the lower and upper first sections. Combinations of horizontal and vertical dimensions of the press are supplied and equipped with various composition covers. This was not used in this series of runs. The calender stack consists of eight intermediate rolls hollowed out for steam. Each roll is made of cold hardened steel, precision milled and supported on friction-resistant bearings. Diameter 36 with a 36 inch face and can be rolled up to 40 inches in diameter
Also includes inch Pope type reels. The production feed of raw materials was dispersed in a hydrapulper at pH 3.0 for a predetermined period of time. The feed was pumped into a 7000 gallon varnish dock chest or two primary stock chests and adjusted to the desired concentration and pH. A papermaking main system Fourdrinier wet end was used for the first layer. Each feed was metered with a Foxboro flow controller and routed from the machine chest to a fan pump that added white water from the screen to the desired paper density. From the fan pump, the diluted feed was metered with a Foxboro flow control controller (full flow) and sent through a five pipe manifold to the headbox. A secondary system Black Clawson second flow hox was placed on top of the fourth foil box and used to form the second layer. The feed was metered with a Foxboro flow controller and pumped from a 7000 gallon stock chest to the flow box. Tape was pasted on the edge of the first press to prevent pressure from being applied to the sheet. All dryers and cans were covered with felt during the test. In all examples, the first slurry was applied to the first slurry from a height of 10° at an angle of 4°15. The first varnish slurry exited at a rate approximately 8% faster than the rate of the first layer. Example 7 (HEPA Filter) Feed Slurry Knee 90% Johns Manville e-glass 112
Fine fiber (average thickness 26-3.8 μnl) type 475
(borosilicate glass with a small amount of zinc oxide). 10%ノJohns Manville Chop P
ak A 20 B G ”'Glass fiber (average thickness 1
5μm). Moisture content Jl when in contact with the 1st layer: 93.32% 0 Basis weight of the 1st layer: 54! i! / Silence. 100% Johns Manville Glass 1
04 fine fiber (average thickness 0.34-0.48 μm)
Type 475° water content M: 99.765 width. Second layer basis weight: 26! ? / Return. Example 8 (HEPA filter) Feed Slurry Knee 90% Johns Manville Glass 1] 0 Fine Fiber (Average Thickness 2.17-3.10 μm) Type 475° 10% Johns Manville Ch
op Pak A20 BC-glass fiber. Water content i when in contact with the second slurry: 94.37%. Basis weight of first layer: 52g/I. 100% Johns Manville Glass 100%
Fine fiber (average thickness 0.2-0.29 μm) type 47
5° Water content: 99.765%. Basis weight of second layer: 26P/valve. This provides a particularly effective HEPA filter, with a substantial density gradient from the coarse first layer to the finer second layer. Example g (HEPA filter) Feed Slurry Knee 90% Johns Manvi 11 e Gas 7s 1
1.0 fine fiber (average thickness, 2.17-3.10 μm
) Type 475°10% (7) Johns Man
ville C: hop Pak A20 BC Yucaras fiber (average thickness 15 μm). Water content iii'i when in contact with the second slurry: 93.72%
. Basis weight of first layer: 559/I. 100% Johns Manville Glass 106
Fine fibers (average thickness 0.49-0.58 μm). Water content: 1 company: 99.769%. The basis weight of the second layer is 29 l/i. Example IO (Battery Separator) Feed Slurry Knee 90% Jobns Manvi Ile Glass 110
Fine fiber type 475°10% (1) Jotu, s Manvill. . hop
Pak A20 B (1: 'Crow fiber. Moisture content H when in contact with the 1st layer: c + 4.41%. Basis weight of the first layer: 5 g/I. 1st layer), OO% Johns Manville glass 1
08A fine fiber (average thickness 0.59-0.88 μm
) Type 753 (borosilicate glass without subsalt oxide). Moisture content: 99.755%. Second layer basis weight: 30P/door. Example 11 (Battery Separator) Feed Slurry Knee 90% C7) Johns Manville Crow 1
10 fine fiber type 475° 10% Johns Manville Chop P
ak A20 BC-glass fiber. Moisture content Ji when in contact with the second slurry: 91.60%. Basis weight of first layer: 155F/silence. 100% Johns Manvi II e-glass 1
08A fine fiber type 475° water content: 99.752%. Second layer basis weight: 40g/door. The paper of the present invention was tested for delamination by adhering double-sided tape to both sides of the paper and pulling the paper outward. The stretched paper was pulled apart and the paper was examined to determine where delamination occurred. For papers such as Examples 7-11, delamination occurred in the first or second layer and the interface remained intact.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a Fourdrinier machine modified to carry out the present invention, FIG. 2 is a detailed diagram of the flow box nozzle portion to which the second slurry is applied, and FIGS. 3 to 7 are: 1 shows micrographs of partial cross-sections of various papers according to the invention showing the interface area at different magnifications; FIG. 1... Fourdrinier machine, 3... Flow box nozzle, 4
... Web, 5... Wet fiber layer, 7... Second flow box, 8... Flow box nozzle, 10...
- Interface, 11... Suction belt, 12... Drying roller, 13... Third flow box. Patent Applicant Whatman Leap Angel Public Limited Company Agent Patent Attorney Aoyama Hajime (and 2 others) Procedural Amendment (
IM5a) December 1982. , Month] 9 [] Dear Commissioner of the Japan Patent Office'' Case indication Patent Application No. 217044 of 1982 2 Title of the invention Paper and its manufacturing method 3 Person making the amendment Relationship to the case Patent applicant address Ghent, United Kingdom EM 142 EL , Maidstone, Springfield Mill (no address indicated) 4 Agent 5 Date of amended order 2 Voluntary

Claims (1)

[Claims] 1. The first slurry has less fluidity than the second slurry,
When both layers have concentrations that are largely flowable, apply a second slurry to the first slurry in such a way that the application is only perturbed at the interface between the surfaces of the first and second layers, and the interlayer A first layer is applied such that a second slurry is applied to control the degree of turbulence and thus the degree of mixing and bonding at the interface and to bond the layers together regardless of the nature of the slurry material. A method of papermaking comprising applying a second slurry under angular, height and speed conditions relative to. 2. The method according to item 1, wherein the first varnish slurry is applied to the second layer from a 7D box nozzle set at an angle of 1.5 to 20 degrees with respect to the first layer surface. 3. The method according to item 1, wherein the first varnish slurry is applied to the first layer from a flow box nozzle set at a height of 1 to 50 feet from the surface of the first layer. 4. The method of item 1, wherein the first varnish slurry is applied to the first layer from a flow hox nozzle such that the varnish slurry flows out below the nozzle at a rate of 102 to 115 fo of the velocity of the first layer. 5. When applying the second slurry, the first layer has a water content of 80 to 95
fo, the first layer has a water content of 98-999%, and the second layer has a water content of 98-999%.
The method described in section. 6. When applying the second slurry, the first layer has a water content of 89 to 91
%, second layer contains water i 99. 6. The method of claim 5, having ()-99.8%. 7. One of the first and second varnish slurries contains fibers finer than the fibers of the other of the first and second varnish slurries;
This produces a first density gradient across the paper.
The method described in section. 8. The method of paragraph 1, wherein each slurry is essentially binder-free. 9. The first slurry has less fluidity than the second slurry,
When both layers have concentrations that are largely flowable, apply a second slurry to the first slurry in such a way that the application is only perturbed at the interface between the surfaces of the first and second layers, and the interlayer A first slurry is applied to control the degree of turbulence at the interface and thereby the degree of mixing and bonding at the interface and to bond the layers together regardless of the nature of the slurry material. A paper formed by applying a second slurry under angle, height and speed conditions relative to the layers. 10, a first layer of first fibers and a second layer of second fibers different from the first fibers, and sufficient first and second fibers mixed together to bond the first and second layers together; A paper with an interface between bonding layers. 11. The paper according to item 10, wherein the bonding strength of the paper at the interface is stronger than the bonding strength of at least one of the two layers. 12. The first, wherein at least one fiber is non-cellulosic.
Paper described in item 0. 13. Paper according to clause 12, wherein the non-cellulose fibers are selected from inorganic fibers and synthetic organic fibers. 14. The first non-cellulose fiber is selected from glass, polyester, polyamide and polyolefin fibers.
Paper described in Section 3. 15, a tenth layer having one layer comprising cellulosic fibers and another layer comprising non-cellulosic fibers;
The paper mentioned in section. 16. The paper according to item 15, wherein the non-cellulose fibers are glass fibers. 17. The paper of claim 10 having two adjacent layers comprising non-cellulosic fibers. 18 The two adjacent layers each include a first layer comprising fibers that are chemically the same as the other fibers but differ in thickness.
Paper described in Section 7. 19. The paper according to item 18, wherein the non-cellulose fibers are glass fibers. 20. The paper of clause 10, wherein one of the first and second layers comprises finer fibers than the fibers of the other of the first and second layers, whereby the paper has a density gradient in the transverse direction. 21. Paper according to clause 10, having only two layers and having a thickness at the interface between 5 and 15 fo of the thickness of the paper. 22 a first layer of first fibers and a second layer of second fibers different from the first fibers, and a second layer of second fibers mixed into the first layer sufficiently to bond the first and second layers together; An improved paper characterized in that essentially only said fibers are present in the paper, having an interface between bonding layers. 23, a first layer of first fibers and a second layer of second fibers different from the first fibers, and a mixture of the first and second fibers sufficient to bond the first and second layers together; paper having an interface between the bonded layers, one of the first and second layers containing finer fibers in the first layer than the fibers in the other of the second layers, and having a density gradient therefrom; A battery separator consisting of 24, a first layer of first fibers and a second layer of second fibers different from the first fibers, and a mixture of the first and second fibers sufficient to bond the first and second layers together; The paper has an interface between the bonding layers, and one of the first and second layers contains finer fibers than the other of the first and second layers, and has a density gradient therefrom. A gas cleaning filter consisting of. 25. Paper according to clause 10, which is essentially binder-free.