JPS6030800B2 - Cellulose products and their manufacturing methods - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to cellulosic products such as paper, and more particularly to electrically insulating papers that are extensible and have insulating properties that make them suitable for use as transformer turn insulators. .

Cellulose products are used in many ways.

The product is required to have flexibility, ballability and strength. For example, cellulose products in paper form can be used as insulation for magnet wires in oil-immersed transformers and motor coils. The most commonly used paper is the rope craft type.

Although this type of paper is generally acceptable, it is unsatisfactory when thin insulation is required for irregular and uneven coil and magnet wire geometries. It's easy to become. In such cases, the paper tends to form gaps and tear when the wire or surface of the paper is bent into a certain shape. Cellulosic products with their flexibility, toughness and strength have further uses, such as as durable packaging and decorative materials.

The electrically insulating paper according to the present invention is produced by treating the base stock to make it malleable and increasing the mass per unit area, and then increasing the mass per unit volume to the density of the base stock, or the density thereof. (except to the point where the material deteriorates, i.e., the material can no longer be used for its intended purpose).

The base stock is desirably rendered malleable by pre-wetting and treatment with a sticky substance.

The mass per unit area is preferably increased by plicating the treated paper stock and compressing it to increase the mass per unit volume. In the case of paper, the base sheet is pre-wetted and treated with a creping compound to crepe and calen it.
dered).

The resulting product desirably weighs from about 0.80 grams per cubic centimeter to about 1.0 grams per cubic centimeter.
Densities ranging from 2 grams, about 1000 to 10000
Gurley densometer in the second range
ensometer) readings, elongation ranging from about 10 percent to about 40 percent, average thickness ranging from about 0.0025 inches to about 0.0045 inches, and ranging from about 20 pounds per inch to about 50 pounds per inch. machine direction tensile strength ranging from about 10 pounds to about 25 pounds machine direction Finch edge tear strength ranging from about 20 foot pounds per square foot to about 5 foot pounds per square foot
Toughness values in the range of 5 foot pounds
Mullen Burst (Mu) ranging from about 25 pounds per square inch to about 50 pounds per square inch
llenBumt) strength, smooth surface properties and suitable compliance to irregular surfaces. Paper products have relatively smooth surfaces and have the ability to adequately accommodate irregular surfaces.

The paper product has special use as an insulating material. Thus, the paper product can be wrapped, for example, in butt layer turns, around magnet wires in oil-immersed transformers, or in coils of electric motors and equipment. - Shape of koji wire direction winding (lo ji jtudi ship loverla
It can also be used for PP skin bags). Generally speaking,
The method for producing electrically insulating paper according to the present invention is based on cellulose.
The base sheet is first wetted by contacting the base sheet with a liquid having a substantially neutral barrier, and then wetted and softened, and the wetted sheet material is creped (cmping).
Some liquid is removed from the sheet material, the span of the sheet is reduced for a given mass of material, and the sheet is compressed while contacting the compound and raising the temperature to a temperature sufficient to impart flexibility. to obtain a crepe product having at least substantially the same density and bulk as the base sheet prior to creping, and having compliance to relatively smooth and irregular surfaces.

More specifically, the method involves pre-greening a cellulose-based sheet and then wetting the sheet to about 500F.
A doctor blade (dMtorbla), which is used with a creping roll, softens the sheet by exposing it to a temperature up to the boiling point of the softener and brings the sheet into close contact with the creping roll.
de) contacting the wet sheet with a sufficient amount of creping compound to effect crimping, and increasing the temperature of some liquid from about 1200F to about 1900F to a temperature sufficient to impart flexibility. from the sheet, reducing the span of the sheet for a given mass of material, and compressing the sheet to obtain a crepe product having substantially the same density and bulk as a non-crepe base sheet. .

In this regard, it should be noted that the density either remains substantially the same value as the starting material or increases in value from the initial value of the starting material. However, in some cases the bulk remains substantially the same, and in some cases the density may increase even though the density remains essentially the same. That is, the formed article may have an average thickness ranging from 0.0025 inches to about 0.0045 inches. A wide variety of wetting and/or softening compounds can be used in practicing this method, so long as they have a substantially neutral pH.

Typical compounds include water, mixtures of water with solvents that are compatible with water, such as lower primary alcohols, including methyl, ethyl, propyl and butyl alcohols. A wide variety of creping compounds, as well as softeners, can be used to affect the adhesion of the base sheet to the creping roll while at the same time allowing the base sheet to be doctor-bladed in conjunction with the creping roll. The material must be crimped.

Such creping materials include natural and synthetic adhesive substances that do not adversely affect the properties of the final product. Typical creping compounds include casein, animal glue, starch, dextriso, carboxymethylcellulose, and the like. However, the only suitable creping compound is carboxymethyl cellulose, which is similar in properties to cellulose sheet materials. In practicing this method, the compaction of the treated sheet can be carried out over a relatively wide range while substantially maintaining the original average thickness of the base sheet, while at the same time increasing the density of the final product to that of the initial base sheet. It must be carried out under sufficient pressure to maintain the density of the sheet substantially the same or to increase the density above its initial value.

In this connection, pressures in the range of about 200 pounds per linear inch to about 600 pounds per linear inch may be used, but preferably about 300 pounds per linear inch.
In the range of about 500 pounds per linear inch. The electrically insulating paper according to the invention can be made from a wide variety of known starting materials.

Generally manufactured in a cylinder or Fourdrinier process, as long as it has a density of about 0.9, a thickness of about 0.0025 inches to 0.0045 inches, and has crepeable properties. Any known paper, whether coated or apricot, is included as a starting material. Additionally, although papers containing natural fibers are preferred, papers containing synthetic fibers or blends or mixtures of both natural and synthetic fibers may be used unless they adversely affect the desired physical and electrical properties. It's okay. Therefore, in this regard, "cellulose material"
It should be understood that includes materials containing natural, synthetic fibers and blends of fibers. Although the electrically insulating paper of the present invention has physical properties within a wide range as described above, approximately 0.9 per cubic centimeter
a density in the range of 0 grams to about 1.0 grams per cubic centimeter; an elongation in the range of about 15 percent to about 30 percent; a machine direction tensile strength in the range of about 25 pounds per inch to about 45 pounds per inch; 1
Machine direction finch green edge tear strength ranging from 5 lbs. to approximately 25 lbs., approximately 25 ft. per square foot.
Preferred properties include ballistic values in the range of about 55 foot-pounds per square foot and Mullen burst strengths in the range of about 30 pounds per square inch to about 45 pounds per square inch.

However, the density is about 0.8 per cubic centimeter.
0 grams or more, preferably about 0.0 grams per cubic centimeter.
95 grams, an elongation greater than about 10 percent, preferably in the range of about 1 percent to about 25 percent, an average thickness of about 0.0030 inches, and a machine direction tensile strength of about 25 percent per inch. It should be noted that suitable products are obtained when the machine direction finch edge tear strength is at least about 15 pounds to about 20 pounds and the Mullen burst strength is at least about 35 pounds per square inch. The electrically insulating paper of the present invention also exhibits a surprising dielectric constant ranging from about 2.4 to about 3.4. In the present invention, after the cellulose-based paper material is moistened as described above, it is creped to increase the mass per unit area, and then compressed in a calendar to reduce the mass per unit volume to at least the unit volume of the base material. It increases the mass of the target to or even more than that.

Here, crepe processing is not performed in terms of volume;
This process is performed in terms of area, and since the area is reduced by crepe treatment, the mass is expressed per unit area in this process. Furthermore, in calendering, the material is compressed and densified to increase the mass per unit volume, so in this process the mass is expressed in terms of per unit volume.

The electrical insulating paper of the present invention can be used in a variety of ways, including magnet wires used in oil-immersed transformers under conditions of high electrical stress, and electric motors and equipment where flexible insulation is desired. To wind the coil used,
This is particularly effective.

In this regard, the insulating product of the invention exhibits unexpected properties. For example, in the production of crepe paper, density is typically reduced by as much as 100 percent and bulk is increased substantially.

On the contrary, as mentioned above, the products of the present invention have a density that may be practically the same as the starting material, i.e., a flat cellulose base sheet, and a thickness or bulk that does not differ substantially from the starting material. shows. Gurley densometer (
Gmleydensometer) readings increase from a range of 500 to 1500 seconds to a range of 1000 to 10000 seconds. At the same time, the product has a smooth surface, considerable extensibility and elasticity, and the ability to properly conform to irregular surfaces without creating gaps or tearing. This contrasts well with currently known insulating materials. Furthermore, when tested on oil-immersed transformers and automobile electric coils, it was found that the
Density of approximately 0.95 grams per cubic centimeter, approximately 1
Fugu - elongation of cents to 25 cents, approximately 0.00
30 inch thickness, machine direction tensile strength of approximately 25 pounds per inch, machine direction finch edge tear strength of approximately 18 pounds, toughness value of 35 foot pounds per square foot, and Mullen strength of approximately 40 pounds per square inch.
Burst strength cellulose insulation products made from crepe paper having an initial density of about 0.9 grams per square centimeter and an average thickness of 0.0030 inches perform excellently under normal operating conditions. It demonstrated its performance.

Furthermore, such materials can be used as magnets with small diameters.
The elastic properties of the paper virtually eliminated any risk of gapping, breakage, etc. when wrapped around the wire in a buttolayer relationship. In addition, the product of the present invention can be
- shape overlapping configuration (overlapped configuration)
When applied to small diameter coiled wires (with arc ration), the assembly can be bent and/or twisted into various shapes without creating gaps or other damage to the turn insulation. I was able to do that. However, commonly used insulating materials, which do not exhibit the elasticity and extensibility or strength possessed by the products of the present invention, pose risks such as the creation of gaps and fractures during manufacturing and assembly operations, which can lead to short circuits during actual use. cannot be manipulated without any possibility of physical damage. As an example of the present invention, finch edge tear strength was measured for the base paper, the creped uncompacted paper, and the final densified paper. 2
3 pounds) and 12.7k9 (28 pounds).

When the base paper and the crepe paper according to the present invention were tested, the following Gurley densometer results were obtained. This result indicates the insulation properties. Gurley densometer process points (pointofp)
rMess) Average: Base paper 651 seconds Final product 231 When testing was attempted by applying 100 cubic centimeters of air through an orifice of 231 square inches, the crepe-treated, uncompacted paper showed There was so much leakage that I couldn't read the Gurley densometer readings.

However, in impact tests for voltage breakdown strength vs. thickness,
1.97 kv/mil for creped and uncompressed paper
However, the final product was 3.33kv/mil.
Met.

Although the present invention is generally disclosed as having application in the field of electrical turn insulation, the product of the present invention is a relatively strong, yet thin, flexible, extensible paper. It should be understood that it can be used anywhere desired.

In addition, when used as an electrical insulator, it may be coated with one or more nitrogen-donating compounds to retard degradation of the material when subjected to electrical, thermal and physical stress over extended periods of time. Products can be processed. The nitrogen-donor compound may be applied to the cellulosic insulation product by jetting, commonly impregnating, or passing through the product. Nitrogen that can be used - Donation -
Compounds include dicyandiamide triethanolamine, melamine, acrylonitrile, and other similar materials. Another advantage is that the cellulosic materials and methods of making them can be carried out using commercially available equipment.

For example, equipment such as pre-wetting machines, creping rolls, creping blades, dryers, calenders, slitters, etc. Generally speaking, the device includes:
Included are pre-wetting equipment, smooth supported creping rolls, creping plaids and equipment such as dryers, calenders and slitters that are arranged in a manner conventionally used in the process of creping materials. The numerical values mentioned above to describe various physical properties are AS. T. M(
AmericanSMiety War Testing
and Ma reals) and T. A. P. P. 1
(Technical Association of
ePulpandPaperIndustry) was obtained by a widely recognized and accepted method.

The details are as follows. Density AS. T. MD202
Ichi7matsu Wet basic elongation A. S. T. M. D202-7
2D828 thickness A. S. T. M. D202-72 Method DM. D. Tensile strength A. S. T. M. D202-7
2D828 Finch Yasushi End Tear A. S. T. M. D827-71 Ballability (tensile energy absorption) T. A. P. P. 1. T494-05-70 Mullen Bursting Strength AS. T. M. D774-71 The product of the present invention has many uses as mentioned above, but it is particularly useful for magnet wire and coils.

To further illustrate, magnet wire for electric motor armature and field coils, transformer coils, 500
It is also effective for transformer magnet wire, electric wire and cables rated below KVA. The numerous features of the products of the present invention, their methods of manufacture, and their uses will be readily apparent to those skilled in the art. Therefore, it should be understood that this invention is not to be limited to the specific examples set forth herein. Next, embodiments of the present invention will be listed.

'1) The method according to claim 3.

'2} The method according to item [1] above, characterized in that the spreading step wets the base material by pre-wetting it. '
3l. A method according to the above item, wherein the step of increasing the mass per unit area comprises the step of decreasing the span of the base material per unit mass.

'41 The method in the above-mentioned Rut 1 item, characterized in that the step of increasing the mass per unit volume comprises the step of compressing the intermediate material.

'5} In the above item A method characterized in that it includes a lower primary alcohol such as.

'61 The method according to item 5 above, characterized in that the softening is carried out at a temperature in the range of about 500F or the boiling point of the softener.

'7) The method according to item {11 above, wherein the base material is a cellulose sheet.

{81 The method of paragraph {71 above, characterized in that the cellulose sheet is creped using a creping roll, and the affinity of the softened sheet for the roll is increased using a creping compound.

'91 Electrical insulating paper produced by the method described in item {1}.

An electrically insulating paper comprising a crepe cellulose sheet having a density ranging from about 0.80 grams per cubic centimeter to about 1.2 grams per cubic centimeter.

(11) A degree of at least about 10 percent, about 0.0
0.025 inch to about 0.0045 inch, machine direction tensile strength of at least about 20 pounds per inch, machine direction finch green edge tear strength of at least about 10 pounds, at least about 20 feet per square foot. lb. toughness value, a Mullen burst strength of at least about 25 pounds per square inch, and a cellulosic material having smooth surface characteristics and the ability to adequately conform to irregular surfaces. Insulating paper.

(12) In the above item (2), at least one nitrogen-
An electrical insulation paper characterized in that the product is impregnated with a donor compound.

(13 In paragraph {10 above, the sheet is made of kraft paper, has a density of 0.95 grams per cubic centimeter, has an elongation of 15 to 2 g centimeters, and has a thickness of 0.00 g.
30 inches, machine direction tensile strength 35 per inch
lbs., an electrically insulating paper characterized by a machine direction finch edge tear strength of 17 lbs. and a Mullen burst strength of 40 lbs. per square inch. (1) The electrically insulating paper according to item {1), characterized in that it is wound around one selected from the class including magnet wires and coils.

(15) Magnet wires for armatures and field coils of electric motors, magnet wires used in dynamo electrical equipment, transformer coils, magnet wires and electric wires and cables for transformer alternators with ratings of 500 KVA or less. Electrical insulating paper according to item (14), characterized in that it is wrapped around a selected one of the included classes so as to provide insulation.

Claims (1)

Claims: 1. An electrically insulating paper comprising a single layer of crepe cellulose sheet having a density ranging from about 0.80 grams per cubic centimeter to about 1.2 grams per cubic centimeter. 2 (a) wetting a single layer of cellulose-based paper; (b) creping the base paper to increase mass per unit area to form an intermediate material; and (c)
) A method for producing electrically insulating paper, comprising the steps of compressing the intermediate material using a calendar to increase the mass per unit volume to at least the mass per unit volume of the base material or more.